Jeb Posted December 17, 2009 Report Share Posted December 17, 2009 Area Forecast Discussion Issued by NWS Sterling, VA http://forecast.weather.gov/product.php?si...p;highlight=off 402AM Dec 17 2009 000 FXUS61 KLWX 170828 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 328 AM EST THU DEC 17 2009 .SYNOPSIS... -- Changed Discussion -- HIGH PRESSURE WILL AFFECT THE AREA TODAY...BEFORE MOVING OFF THE COAST TONIGHT. LOW PRESSURE WILL DEVELOP ALONG THE COASTLINE OF THE GULF OF MEXICO LATE TONIGHT...AND EMERGE OFF THE COAST OF THE CAROLINAS FRIDAY NIGHT. THIS STORM WILL THEN TRACK UP THE EASTERN SEABOARD SATURDAY AND SATURDAY NIGHT. COLD HIGH PRESSURE WILL BUILD FOR THE FIRST HALF OF NEXT WEEK. -- End Changed Discussion -- && .NEAR TERM /UNTIL 6 PM THIS EVENING/... -- Changed Discussion -- ANOTHER DAY OF QUIET WX...AHEAD OF A POSSIBLE WINTRY SCENARIO FOR THE COMING WEEKEND. NOT MUCH ACTIVITY ONGOING ACROSS THE CONUS... BUT A RELATIVELY SMALL DISTURBANCE JUST OFF THE TX GULF COAST WILL CONTINUE TO STRENGTHEN OVER THE COURSE OF THE DAY AND INTO TOMORROW. AN UPPER LOW ROTATING OVER NOVA SCOTIA WILL REMAIN SITUATED IN THAT GENERAL AREA INTO THE WEEKEND...KEEPING A STEADY STREAM OF NWLY WINDS AND COLDER-DRIER AIR SLIDING DOWN INTO THE NORTHEAST AND MID ATLC. HIGHS TODAY WILL BE COMPARABLE TO YESTERDAY...AS ANOTHER PERIOD OF 10-15MPH WINDS PICK-UP DURING THE LATE MRNG-EARLY AFTN HRS AND KEEP WIND CHILL VALUES ABOUT 10 DEGREES BELOW THE AMBIENT TEMP. SKIES WILL REMAIN MOSTLY CLEAR THROUGHOUT THE MRNG...THEN A STEADY STREAM OF UPPER CIRRUS /FOLLOWED BY MID LEVEL STRATUS/ WILL MAKE AN APPEARANCE DURING THE AFTN-EVNG HRS. -- End Changed Discussion -- && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/... -- Changed Discussion -- OTHER THAN A FAIRLY SOLID LAYER OF UPPER CIRRUS AND INCREASING AMOUNTS OF MID CLOUD DECKS...ANOTHER SIMILAR OVERNIGHT PERIOD FOR THU NIGHT/FRI MRNG. CLOUD COVER WILL KEEP THE STRATIFICATION OF TEMPS ACROSS THE AREA FAIRLY LOW /EVERYONE RANGING IN THE L-M20S FROM THE MTNS TO THE BAY/. -- End Changed Discussion -- && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... -- Changed Discussion -- MDL GDNC /OP RUNS AND ENSEMBLES/ CNVGG TWD A WKND SNW EVENT ACRS CWFA. THE MAIN PIECES SEEM TO BE FALLING INTO PLACE-- SRN STREAM LOPRES CROSSES THE GLFMEX CST PICKING UP AMPLE MSTR FRI AND THEN TRANSFERS THAT ENERGY TO THE CAROLINA COAST AS IT INTERACTS W/ H5 TROF AXIS. STORM SUBSEQUENTLY ATTAINS NEG TILTING AS IT DEEPENS AND TRACKS TWD NEW ENGLND SUNDAY. SFC LOW PROGGED TO BE CLS ENUF TO COAST TO PROVIDE DECENT PCPN FM NOT JUST THE GLFMEX CONNECTION BUT ALSO ACCESSING ATLC MSTR...BUT TRACK WL STILL BE S OF CWFA. H8 LOW ALSO PROGGED TO BE S OF CWFA. THUS...MDL SNDGS AND CRIT TKNS VALUES ALL SUGGEST IT WL BE PLENTY COLD FOR JUST SNW. THOSE SIGNS ALL SUGGEST THAT CWFA WL BE W/IN BAND OF HVYR QPF. BUT...DO XPCT A THERMAL GRADIENT WHICH LKLY WL CLIP SERN CRNR OF CWFA...MAINLY SRN MD...MEANING THERE WL BE A RA/SN LINE TO DEAL WITH. HAVING SAID THAT...THERE ARE SMALL DIFFS IN MDL GDNC WHICH WL HV BIG RAMIFICATIONS IN THE END FCST. /FOR ONE THING...ITS STILL WAY TOO ELY TO PIN DOWN QPF./ SINCE THERE IS THAT ASPECT OF UNCERTAINTY AND STORM WL BE IN FCST PDS 4-6...WON/T BE ISSUING A WATCH JUST YET. /DAYSHIFT MAY NEED TO IF 06Z-12Z GDNC PAINTS A SIMLR PICTURE./ BUT...WL BUMP UP POPS SIGNIFICANTLY /LKLY-CAT/ FRI NGT-SAT NGT W/ THIS CYCLE. WL MAKE CORRESPONDING ADJUSTMENTS TO TEMPS AS WELL... SPCLY MAXT SAT-SUN...SINCE TEMPS WL STRUGGLE TO RISE IN LIGHT OF POTL SNWFL. ONCE H5 TROF SWINGS THRU...FLOODGATES OPEN FOR MORE COLD AIR FOR THE 1ST HALF OF NXT WEEK. THAT ALSO SHUD EQUATE TO UPSLP SHSN FOR OUR WRN TIER. -- End Changed Discussion -- && .AVIATION /09Z THURSDAY THROUGH MONDAY/... -- Changed Discussion -- HIGH PRESSURE WILL KEEP CONDITIONS QUIET INTO NEXT WEEKEND. BREEZY NWLY WINDS WILL AGAIN PICK-UP THIS MRNG...LINGERING THRU THE AFTN THEN DECREASING TO NEAR CALM BY LATE TONIGHT. A LOW PRESSURE SYSTEM GATHERING OVER THE TX GULF COAST WILL BEGIN TO AFFECT THE REGION BY LATE FRI...BUT LITTLE CONCERN WX-WISE TILL THEN. CONDS DETERIORATE FRI AFTN-NGT AS LOPRES FM GLFMEX CST TRANSFERS ENERGY OFF THE CAROLINA COAST AND TRACKS NEWD. MAIN PTYPE WL BE SNW. IFR OR LWR SEEMS PLAUSIBLE LT FRI NGT/ELY SAT MRNG INTO SAT EVE. SOME DETAILS /TIMING/AMTS/ STILL NEED TO BE WORKED OUT...SO WON/T BE GETTING TOO SPECIFIC ATTM. CONDS WL BE IMPVG BY SUN. CUD BE A FEW MVFR PDS...BUT VFR SHUD PREVAIL. -- End Changed Discussion -- && .MARINE... -- Changed Discussion -- SCA THRU LATE THIS AFTN. WINDS ARE NOTICEABLY STRONGER CLOSER TO /AND OVER/ THE MD CHESAPEAKE. A TIGHTENING PRESSURE GRADIENT HELPING TO KEEP 15-20 KT GUSTS OVER THE WATERS...W/ INTERMITTENT GUSTS NEAR 25 KT. THIS WILL LINGER THRU THE LATE MRNG AND INTO THE MID AFTN...GRADUALLY TAPERING OFF BY EVNG. LOPRES ALNG GLFMEX CST FRI WL TRANSFER OFF CAROLINA CST SAT...AND TRACK TO NEW ENGLND SUN. STORM WL BE STRENGTHENING WHILE IN WRN ATLC...AND LTST GDNC PAINTS A STRONGER STORM CLSR TO THE CST. GIVEN SUCH A LRG CONTINUITY SHIFT...AM HESITANT TO OFFER UP GALES ATTM... BUT IT CERTAINLY SEEMS PLAUSIBLE BASED ON LTST PROGS. WL CAP WNDS AT 30KT IN THE GRIDS LT FRI NGT/ELY SAT MRNG THRU ELY SUN...MAINLY IMPACTING LWR PTMC AND MID BAY. SCA CONDS SHUD CONT PAST SUN. WL ALSO BE VSBY RESTRICTIONS AS PCPN /RASN XCPT SNW UPR REACHES BAY AND MOST OF PTMC/ MVS IN FRI EVE AND CONTS THRU SAT. ONCE STORM MVS N OF DELMARVA /RIGHT NOW THAT APPEARS TO BE SAT EVE/...COLD AIR WL RUSH IN CHGG ALL PCPN TO SNW. -- End Changed Discussion -- && .LWX WATCHES/WARNINGS/ADVISORIES... -- Changed Discussion -- DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ530>534-537>543. -- End Changed Discussion -- && $$ SYNOPSIS...HTS NEAR TERM...GMS SHORT TERM...GMS LONG TERM...HTS AVIATION...GMS/HTS MARINE...GMS/HTS ------------------------ Link to comment Share on other sites More sharing options...
Jeb Posted December 18, 2009 Author Report Share Posted December 18, 2009 Area Forecast Discussion Issued by NWS Sterling, VA http://forecast.weather.gov/product.php?si...p;highlight=off 000 FXUS61 KLWX 180849 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 349 AM EST FRI DEC 18 2009 .SYNOPSIS... -- Changed Discussion -- HIGH PRESSURE WILL MOVE EAST OF THE AREA TODAY. LOW PRESSURE ALONG THE GULF COAST WILL EMERGE OFF THE COAST OF THE CAROLINAS TONIGHT. THIS STORM WILL THEN TRACK ALONG THE EAST COAST SATURDAY THROUGH SUNDAY MORNING. A WEAK DISTURBANCE TO CROSS THE MID- ATLANTIC REGION EARLY NEXT WEEK BEFORE HIGH PRESSURE BUILDS IN FOR THE MIDDLE PART OF THE WEEK. -- End Changed Discussion -- && .NEAR TERM /UNTIL 6 PM THIS EVENING/... -- Changed Discussion -- LITTLE TO SPEAK OF WX-WISE THRU MIDDAY FRI. THE APPROACHING STORM SYSTEM THAT IS EXPECTED TO BE A SNOW-MAKER FROM SOUTHERN APPALACHIANS TO THE NEW ENGLAND IS CURRENTLY STRENGTHENING OVER THE GULF COAST STATES. A REGIONAL-SCALE FETCH OF LOW LEVEL MOISTURE STREAMING UP THE SOUTHEAST...FROM LA TO SC. THE LEADING EDGE OF THE PRECIP WILL BE EXPANDING UP THE ERN SEABOARD THRU THE DAYTIME HRS. TEMPS WILL GRADUALLY RISE CLOSE TO FREEZING BY LATE MRNG AS THE STORM SYSTEM IS STILL WELL TO THE SOUTH...AND ONLY BANDS OF MID- HIGH CLOUDS WILL BE STREAMING INTO THE MID ATLC. HIGHS NOT EXPECTED TO RISE MUCH MORE THAN THAT...LIKELY STILL IN THE L-M30S BY MID AFTN...MODERATING FROM THERE AS MORE SOLID CLOUD COVER PUSHES IN FROM THE SW AND FROM A WEAK ELY ONSHORE FLOW AS A WEAK SFC HIGH OVER SRN QUEBEC HELPS TO REINFORCE THE RELATIVELY COLDER AIR IN THE LOW LEVELS. -- End Changed Discussion -- && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... -- Changed Discussion -- AS THE LEADING EDGE OF PRECIP BEGINS TO WORK THRU THE DRIER REGIME BY LATE FRI AFTN-EARLY EVENING...A FEW SNOW FLAKES WILL BEGIN TO FALL ACROSS THE SOUTHERNMOST PORTIONS OF THE CWA JUST AFTER SUNSET. PCPN WILL LIKELY BE VERY LIGHT FOR THE FIRST FEW HRS W/ LITTLE-NO ACCUMULATION EXPECTED UNTIL LATER IN THE EVENING. THIS COMPLEX STORM SYSTEM HAS TWO MAIN PHASES. THE FIRST PHASE AFFECTS THE MID ATLC MAINLY FOR THE LATE NIGHT-OVERNIGHT HRS ON FRI...INTO EARLY SAT. A DYNAMIC MESOSCALE REGION OF MODERATE SNOW...W/ EMBEDDED AREAS OF HEAVY SNOW...WILL BE SETTING UP ACROSS THE LEE OF THE SRN-CNTRL APPALACHIANS...AN EFFECT OF THE PROXIMITY OF THE SHORTWAVE ACROSS THE MID MISSISSIPPI VLY AND THE COASTAL LOW OFF THE CAROLINAS. AS THE COASTAL LOW STRENGTHENS OFF THE SC/NC COAST /MYRTLE BEACH-WILMINGTON/ LATE FRI NIGHT...THIS MESOSCALE AREA OF HEAVIER PRECIP WILL BE MAXIMIZED IN BETWEEN I-81 AND I-95 OF SRN VA TOWARD THE LATE NIGHT HRS. AN EVEN STRONGER COASTAL LOW DEPICTED FROM THE LATEST NAM SUGGESTS THAT THIS CORRIDOR OF PRECIP /WHICH WOULD BE ALL SNOW ONCE IT ENTERS OUR CWA/ WILL BE FAIRLY WELL MAINTAINED AS IT PUSHES NORTH- NORTHEASTWARD INTO THE OVERNIGHT HRS. THE AREA HIGHLIGHTED FOR ACCUMULATING SNOWS WILL BE TO THE SOUTH OF THE I-66 CORRIDOR W/ THE HIGHEST AMOUNTS OVER EXTREME W CNTRL VA...INTO THE NEARBY BLUE RIDGE AND FOOTHILLS. WHILE THE HEAVIEST CORRIDOR OF SNOW BANDING WILL BE PROPAGATING UP THE VA/MD PIEDMONT INTO THE PRE-DAWN HRS SAT...SNOW WILL CONTINUE TO FALL OVER THE CNTRL-SRN SHENANDOAH VLY...ADDING TO THEIR OVERNIGHT ACCUMULATIONS. THE FOCUS WILL THEN SHIFT TOWARD THE METRO AREAS. -- End Changed Discussion -- && .LONG TERM /SATURDAY THROUGH THURSDAY/... -- Changed Discussion -- MDL GDNC REMAINS QUITE CONSISTENT ON A BIG EAST COAST NOREASTER SAT- SAT NGT. THE QSTNS RIGHT NOW HOVER ARND HOW MUCH AND WHEN...NOT IF. GFS SEEMS A BIT FLAT CONSIDERING THE POTL. ON THE OTR HAND... NAM QPF GROSSLY OVERDONE. THEREIN LIES THE UNCERTAINTY. ON SAT...CSTL LOW PASSES JUST E OF CWFA...AND INTERACTS W/ H5 TROF. STORM THEN LIFTS NE OF CWFA SAT NGT. EVEN IF FULL PHASING DOES NOT OCCUR...THE DEFORMATION AXIS WL BE ACRS CWFA...SUPPORTING A SWATH OF MDT-HVY SNW-- NOT EVEN SPEAKING OF LCL BANDING. WHILE SNW WL START ERLR...ACCUM PCPN WL SPREAD IN EARNEST INTO METROS ON SAT...W/ MAX IMPACT LKLY SAT AFTN-EVE INVOF DEF AXIS. CYCLONE PLENTY JUICED FM GLFMEX...AND WL IMPORT ADDTL MSTR FM ATLC. THERMALLY... COLUMN COLD ENUF FOR ALL SNW ACRS ENTIRE CWFA. ENUF INGREDIENTS TO RAISE WRNG. PLEASE NOTE...TTL ACCUMS WL NEED TO BE FINE TUNED IN THE CYCLES TO COME. SUFFICE IT TO SAY...THE WRNG THRESHOLD WL BE SURPASSED. THERE/S ALWAYS A BIT OF UNCERTAINTY IN FCSTG EXTREME EVENTS...AND HV ATTEMPTED TO STRIKE A BALANCE CONVEYING THE THREAT IN A RESERVED MANNER. IN ADDITION...LOOKING FOR WNDS TO PICK UP TOO AS THE P-GRAD INCR... ADDING BLOWING/DRIFTING CONCERNS. PCPN LKLY TO WIND DOWN SUN MRNG AS LOW DEPARTS. THE UPSLP EVENT THEN WL UNFOLD. LATER FCSTRS WL NEED TO ADDRESS THAT CONCERN. IT/LL BE PLENTY COLD FOR THE WK AHD. -- End Changed Discussion -- && .AVIATION /09Z FRIDAY THROUGH TUESDAY/... -- Changed Discussion -- VFR CONDITIONS THRU MUCH OF THE CURRENT TAF PERIOD...BUT A LOW PRESSURE SYSTEM WILL BE FAST APPROACHING THE MID ATLC BY LATE IN THE DAY ON FRIDAY. SNOW WILL BEGIN TO FALL AT LOCALES SUCH AS KCHO BY FRI EVENING...AND MOVE INTO THE DC/BALT METRO AREAS INTO THE LATE NIGHT HRS /AND INCREASING IN INTENSITY OVERNIGHT/. BY THE PRE-DAWN HRS...MOST OF THE AREA TAF SITES WILL BE IN STEADILY FALLING SNOW...W/ THE HEAVIEST ACTIVITY ALONG THE I-95 CORRIDOR GOING INTO THE MORNING HRS ON SAT. LESSER INTENSITIES AND DURATIONS ACROSS THE NRN SHENANDOAH VLY...LIKE KMRB/KHGR. POOR FLYING CONDS SAT-SAT NGT /AOB IFR VSBYS/CIGS/ IN SNW. IMPVMNT COMES SUN. -- End Changed Discussion -- && .MARINE... -- Changed Discussion -- WINDS NEAR CALM AROUND THE REGION...W/ WEAK NLY SURGES CLOSER TO 10 KT INTO THE EARLY MRNG HRS. FOR MUCH OF TODAY...WINDS WILL REMAIN RELATIVELY LIGHT...CHANGING TO MORE ELY BY THIS AFTN...THEN NELY INTO THE LATE EVENING. A LOW PRESSURE SYSTEM JUST OFF THE CAROLINA COAST WILL BEGIN TO AFFECT THE REGION BY SPREADING SNOW ACROSS THE MID ATLC AND A MIX OF RAIN-SNOW CLOSER TO THE BAY...CHANGING MAINLY TO ALL SNOW INTO THE OVERNIGHT HRS FRI. AS THE COASTAL LOW STRENGTHENS INTO EARLY SAT AND GETS CLOSER TO THE TIDEWATER REGION...SO WILL WINDS ACROSS THE BAY. SCA CONDITIONS WILL BE APPARENT BY EARLY SAT. CYCLONE DEEPENS OFF DELMARVA SAT-SAT NGT...MAKING GLW A VERY REAL PSBLTY. HV UPGRADED TO GLW FOR MOST OF BAY/LWR PTMC...STRONG SCA ELSW. WL LET LATER FCSTRS HANDLE THE ENDING OF THE EVENT. -- End Changed Discussion -- && .TIDES/COASTAL FLOODING... -- Changed Discussion -- LOW PRESSURE WILL INTENSIFY OFF THE CAROLINA COAST TONIGHT...MOVING NEAR THE MOUTH OF THE BAY LATE TONIGHT AND INTO SATURDAY. PROLONGED NORTHEASTERLY FLOW WILL BUILD EXCESS WATER INTO THE BAY...BRINGING POSITIVE TIDAL DEPARTURES TONIGHT AND SATURDAY. THERE WILL BE POTENTIAL FOR MINOR COASTAL FLOODING WITH THIS SYSTEM. STRONG NORTHERLY FLOW SATURDAY WILL REMOVE EXCESS WATER FROM THE BAY THROUGH SUNDAY NIGHT. -- End Changed Discussion -- && .LWX WATCHES/WARNINGS/ADVISORIES... -- Changed Discussion -- DC...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR DCZ001. MD...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR MDZ003>007-009>011-013-014-016>018-501-502. VA...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR VAZ028-031-042-052>054. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR VAZ021-025>027-029-030-036>041-050-051-055>057. WV...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR WVZ050>053-503-504. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR WVZ054-055-501-502. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST SATURDAY FOR ANZ531-532-539-540. GALE WARNING FROM 6 AM TO 10 PM EST SATURDAY FOR ANZ531>534- 537-539>543. SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST SATURDAY FOR ANZ533-534-537-541>543. SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM EST SATURDAY FOR ANZ530-535-536-538. -- End Changed Discussion -- && $$ SYNOPSIS...HTS NEAR TERM...GMS SHORT TERM...GMS LONG TERM...HTS AVIATION...GMS/HTS MARINE...GMS/HTS TIDES/COASTAL FLOODING...HTS ------------------------- Link to comment Share on other sites More sharing options...
Jeb Posted December 19, 2009 Author Report Share Posted December 19, 2009 Area Forecast Discussion Issued by NWS Sterling, VA http://forecast.weather.gov/product.php?si...p;highlight=off 000 FXUS61 KLWX 191532 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1032 AM EST SAT DEC 19 2009 .SYNOPSIS... LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL INTENSIFY AND MOVE ALONG THE COAST AND OFF THE DELMARVA TONIGHT AND EAST OF LONG ISLAND SUNDAY MORNING. A WEAK DISTURBANCE WILL CROSS THE MID-ATLANTIC REGION LATE MONDAY BEFORE HIGH PRESSURE BUILDS IN FOR THE MIDDLE PART OF THE WEEK. A STRONG UPPER DISTURBANCE IS EXPECTED TO IMPACT THE MID-ATLANTIC FOR CHRISTMAS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... -- Changed Discussion -- LOW PRES INVOF KHSE...989MB...AND WL CONT INTENSIFY AS IT APRCHS THE DELMARVA LATE THIS AFTN/ERLY EVE. BANDS OF HVIEST RDR RETURN ACROSS CENTRAL VIRGINIA HAS NE- SW ALIGNMENT. HVIEST SNOWFALL AREA WL MOVE FM THE CENTRAL SHEN VALLEY UP TOWARDS DC/BALT/NHK...WHERE IT WL CONT TO SNOW HEAVILY THRUT THE DAY. STORM TOTALS 2 TO 2.5 FT INVOF CHO WHERE 16.5 WAS REPORTED AT 9 AM...ALONG THE ALLEGHENY FRONT...AND 1.5 TO 2 FT ALONG THE THE I-95 CORRIDOR. BLIZZARD WARNING EXPANDED TO GREATER I-95 CORRIDOR AND SOUTHERN MARYLAND. PERIODS AND HEAVY SNOW AND GUSTY WINDS ARE EXPECTED THROUGH THE AFTERNOON HOURS OF THE BLIZZARD AREA. SNOW IS STARTING TO TAPER OFF FOR SW ZONES...A FEW BANDS TO CROSS OUT THERE BRINGING A FEW MORE INCHES. MIXED PRECIP FOR LOWER ST MARYS/SOUTHERN CALVERT COUNTY TO TURN TO ALL SNOW THROUGH MIDDAY. PLEASE CHECK CLIMATE SXN FOR TWO DAY DEC SNOW TOTALS. -- End Changed Discussion -- && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... BLV SNOW WL BECOME LGT TNGT IN THE SW...BUT XPCTD TO CONT AT A MDT PACE IN I-95 CORRIDOR DURG THE EVE HRS. TEMPS OVRNGT IN 20S ACROSS THE CWA - WIND CHILLS IN THE TEENS. && .LONG TERM /SUNDAY THROUGH FRIDAY/... SNOW XPCD TO TAPER OFF SUN AS LOPRES MOVES QUICKLY AWAY FROM RGN. WNWLY LOW-LVL FLOW AND APRCH OF A LOW-AMPLITUDE SHRTWV TROF WILL PROMOTE UPSLP SNOW SHOWERS ALONG WRN SLOPES OF ALLEGHENY FRONT THRU MON NGT. COLD AIR RMNS PRESENT THRU MUCH OF NEXT WEEK OWING TO PERSISTENT SNOW PACK. A STRONG CLOSED UPR LOW XPCD TO FORM OVER SRN PLNS MID WEEK AND COULD RESULT IN PCPN THU-FRI. ATTM...MODELS SUGGEST A TRANSITION FROM SNOW INITIALLY TO RAIN AS WARM AIR IS DRAWN INTO THE SYSTEM. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... -- Changed Discussion -- TAFS CONTINUE TO BE BURIED IN VLIFR CIGS/VSBYS THRUT THE DAYLGT HRS. SNOW THROUGH THE AFTERNOON PERIODS OF HEAVY SNOW WITH BANDED PRECIPITATION. ALTHO THERE MAY BE SOME MINOR IMRVMNTS GETTING IN/OUT OF THE THREE MAJOR AIRPORTS WL BE XTRMLY DIFFICULT THIS EVENG. MAIN PSBLTY FOR TERMINAL IMPACTS IN EXTENDED PDS IS THU-FRI NEXT WEEK...WHEN A DEEP CLOSED UPR LOW WILL APRCH APLCNS AND COULD GENERATE RAIN/SNOW OVER MUCH OF MID-ATLC RGN. -- End Changed Discussion -- && .MARINE... -- Changed Discussion -- LOW PRESSURE NEAR HATTERAS MOVING NE. GRADIENT HAS INCREASED...GALES FOR THE WATERS THROUGH TONIGHT. ANY MIXED PRECIP OVER THE WATER TO CHANGE OVER TO ALL SNOW THIS AFTERNOON. SMALL CRAFT ADVISORY WILL BE WARRANTED FOR THE WATERS SUNDAY THROUGH SUNDAY NIGHT. STRONGER NW WINDS CONTINUE THROUGH MONDAY/MONDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE WATERS. -- End Changed Discussion -- && .TIDES/COASTAL FLOODING... -- Changed Discussion -- PROLONGED NORTHEASTERLY FLOW HAS BUILT POSITIVE ANOMALIES INTO THE BAY. ATTM TIDAL LVLS ARE APPROACHING TWO FEET ABOVE PREDICTED FOR LOWER TIDAL POTOMAC AND LOWER PORTIONS OF THE MD CHES BAY. A COASTAL FLOOD ADVISORY WILL GO UP FOR CALVERT..ST MARYS...CHARLES...KING GEORGE COUNTIES SOON. POSITIVE TIDAL DEPARTURES OF UP TO ONE FOOT ABOVE NORMAL ARE POSSIBLE REST OF THE WATERS TODAY. -- End Changed Discussion -- && .CLIMATE... -- Changed Discussion -- MID ATLC LOOKS ON ITS WAY TO RECORD DEC SNOWFALL - TWO DAY DEC RECORDS FOR MAJOR AIRPORTS: DCA 12.0" 1932 BWI 14.1" 1960 IAD 12.1" 1969 -- End Changed Discussion -- && .LWX WATCHES/WARNINGS/ADVISORIES... -- Changed Discussion -- DC...WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR DCZ001. BLIZZARD WARNING UNTIL 6 PM EST THIS EVENING FOR DCZ001. MD...WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR MDZ006-007-009>011-013-014-016>018. BLIZZARD WARNING UNTIL 6 PM EST THIS EVENING FOR MDZ006-007- 009>011-013-014-016>018. WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR MDZ003>005-501- 502. VA...WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR VAZ052>057. BLIZZARD WARNING UNTIL 6 PM EST THIS EVENING FOR VAZ052>057. WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR VAZ021-025>031- 036>042-050-051. WV...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ050>055- 501>504. MARINE...GALE WARNING UNTIL 6 AM EST SUNDAY FOR ANZ530>543. -- End Changed Discussion -- && $$ UPDATE...BAJ PREVIOUS DISCUSSION...ABW/BPP/JRK ----------- Link to comment Share on other sites More sharing options...
Jeb Posted December 20, 2009 Author Report Share Posted December 20, 2009 000 WWUS41 KLWX 191939 WSWLWX URGENT - WINTER WEATHER MESSAGE NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 239 PM EST SAT DEC 19 2009 DCZ001-MDZ006-007-009>011-VAZ052>057-200345- /O.CAN.KLWX.BZ.W.0001.000000T0000Z-091219T2300Z/ /O.CON.KLWX.WS.W.0008.000000T0000Z-091220T1100Z/ DISTRICT OF COLUMBIA-NORTHERN BALTIMORE-HARFORD-MONTGOMERY-HOWARD- SOUTHERN BALTIMORE-PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX- ARLINGTON/FALLS CHURCH/ALEXANDRIA-STAFFORD-SPOTSYLVANIA- KING GEORGE- INCLUDING THE CITIES OF...WASHINGTON...GAITHERSBURG...COLUMBIA... BALTIMORE...MANASSAS...MANASSAS PARK...FAIRFAX...ALEXANDRIA... FALLS CHURCH...FREDERICKSBURG 239 PM EST SAT DEC 19 2009 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY... ...BLIZZARD WARNING IS CANCELLED... THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS CANCELLED THE BLIZZARD WARNING. A WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY. * PRECIPITATION TYPE...SNOW. * ACCUMULATIONS...STORM TOTAL ACCUMULATIONS OF 14 TO 22 INCHES. * TIMING...SNOW WILL BE HEAVIEST THROUGH 9 PM TONIGHT. SNOW WILL CONTINUE THROUGH EARLY SUNDAY MORNING. * TEMPERATURES...MID TO UPPER 20S. * WINDS...15 TO 20 MPH...WITH GUSTS UP TO 25 MPH. PRECAUTIONARY/PREPAREDNESS ACTIONS... A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW... SLEET...AND ICE ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO POSSIBLE. THIS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE. && $$ MDZ013-014-016>018-200345- /O.CAN.KLWX.BZ.W.0001.000000T0000Z-091219T2300Z/ /O.EXT.KLWX.WS.W.0009.091219T1939Z-091220T1100Z/ PRINCE GEORGES-ANNE ARUNDEL-CHARLES-ST. MARYS-CALVERT- INCLUDING THE CITIES OF...ANNAPOLIS...WALDORF...ST MARYS CITY 239 PM EST SAT DEC 19 2009 ...WINTER STORM WARNING NOW IN EFFECT UNTIL 6 AM EST SUNDAY... ...BLIZZARD WARNING IS CANCELLED... THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS CANCELLED THE BLIZZARD WARNING. THE WINTER STORM WARNING IS NOW IN EFFECT UNTIL 6 AM EST SUNDAY. * PRECIPITATION TYPE...SNOW. * ACCUMULATIONS...STORM TOTAL ACCUMULATIONS OF 12 TO 18 INCHES. * TIMING...SNOW WILL BE HEAVIEST THROUGH 7 PM TONIGHT. SNOW WILL CONTINUE THROUGH EARLY SUNDAY MORNING. * TEMPERATURES...MID TO UPPER 20S. * WINDS...15 TO 25 MPH...WITH GUSTS UP TO 30 MPH AT COASTAL LOCATIONS. PRECAUTIONARY/PREPAREDNESS ACTIONS... A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW... SLEET...AND ICE ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO POSSIBLE. THIS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE. && $$ VAZ021-025-026-036>039-050-WVZ054-200345- /O.CON.KLWX.WS.W.0008.000000T0000Z-091220T1100Z/ HIGHLAND-AUGUSTA-ROCKINGHAM-NELSON-ALBEMARLE-GREENE-MADISON- ORANGE-PENDLETON- INCLUDING THE CITIES OF...STAUNTON...WAYNESBORO...HARRISONBURG... CHARLOTTESVILLE 239 PM EST SAT DEC 19 2009 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY... A WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY. * PRECIPITATION TYPE...SNOW. * ACCUMULATIONS...STORM TOTAL ACCUMULATIONS OF 14 TO 24 INCHES. * TIMING...SNOW WILL CONTINUE THROUGH TONIGHT. * TEMPERATURES...MID TO UPPER 20S. * WINDS...10 TO 15 MPH WITH GUSTS TO 25 MPH. PRECAUTIONARY/PREPAREDNESS ACTIONS... A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO POSSIBLE. CONDITIONS WILL DETERIORATE VERY RAPIDLY LATE TONIGHT AND WILL MAKE TRAVEL EXTREMELY TREACHEROUS. && $$ MDZ501-502-VAZ027>031-WVZ050-055-501>504-200345- /O.CON.KLWX.WS.W.0008.000000T0000Z-091220T1100Z/ EXTREME WESTERN ALLEGANY-CENTRAL AND EASTERN ALLEGANY-SHENANDOAH- FREDERICK VA-PAGE-WARREN-CLARKE-HAMPSHIRE-HARDY-WESTERN GRANT- EASTERN GRANT-WESTERN MINERAL-EASTERN MINERAL- INCLUDING THE CITIES OF...FROSTBURG...CUMBERLAND...WINCHESTER... FRONT ROYAL...BAYARD...PETERSBURG...EMORYVILLE...HARTMANSVILLE... KEYSER...FORT ASHBY 239 PM EST SAT DEC 19 2009 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY... A WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY. * PRECIPITATION TYPE...SNOW. * ACCUMULATIONS...STORM TOTAL ACCUMULATIONS OF 12 TO 24 INCHES. * TIMING...SNOW WILL CONTINUE THROUGH TONIGHT. * TEMPERATURES...LOW TO MID 20S. * WINDS...10 TO 15 MPH...WITH GUSTS TO 25 MPH. PRECAUTIONARY/PREPAREDNESS ACTIONS... A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO POSSIBLE. CONDITIONS WILL DETERIORATE VERY RAPIDLY EARLY TODAY MORNING AND WILL MAKE TRAVEL EXTREMELY TREACHEROUS. && $$ MDZ003-WVZ051>053-200345- /O.CON.KLWX.WS.W.0008.000000T0000Z-091220T1100Z/ WASHINGTON-MORGAN-BERKELEY-JEFFERSON- INCLUDING THE CITIES OF...HAGERSTOWN...MARTINSBURG...CHARLES TOWN 239 PM EST SAT DEC 19 2009 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY... A WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY. * PRECIPITATION TYPE...SNOW. * ACCUMULATIONS...STORM TOTAL ACCUMULATIONS OF 12 TO 24 INCHES. * TIMING...SNOW WILL CONTINUE THROUGH EARLY SUNDAY MORNING. * TEMPERATURES...MID 20S. * WINDS...10 TO 20 MPH. PRECAUTIONARY/PREPAREDNESS ACTIONS... A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO POSSIBLE. CONDITIONS WILL DETERIORATE VERY RAPIDLY TODAY MORNING AND WILL MAKE TRAVEL EXTREMELY TREACHEROUS. && $$ VAZ040-041-051-200345- /O.CON.KLWX.WS.W.0008.000000T0000Z-091220T1100Z/ RAPPAHANNOCK-FAUQUIER-CULPEPER- INCLUDING THE CITIES OF...WASHINGTON...CULPEPER 239 PM EST SAT DEC 19 2009 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY... A WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY. * PRECIPITATION TYPE...SNOW. * ACCUMULATIONS...STORM TOTAL ACCUMULATIONS OF 14 TO 24 INCHES. * TIMING...SNOW WILL CONTINUE THROUGH LATE TONIGHT. * TEMPERATURES...MID 20S. * WINDS...10 TO 15 MPH...WITH GUSTS TO 25 MPH. PRECAUTIONARY/PREPAREDNESS ACTIONS... A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO POSSIBLE. CONDITIONS WILL DETERIORATE VERY RAPIDLY TODAY MORNING AND WILL MAKE TRAVEL EXTREMELY TREACHEROUS. && $$ MDZ004-005-VAZ042-200345- /O.CON.KLWX.WS.W.0008.000000T0000Z-091220T1100Z/ FREDERICK MD-CARROLL-LOUDOUN- INCLUDING THE CITIES OF...FREDERICK...WESTMINSTER...LEESBURG 239 PM EST SAT DEC 19 2009 ...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY... A WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 AM EST SUNDAY. * PRECIPITATION TYPE...SNOW. * ACCUMULATIONS...STORM TOTAL ACCUMULATIONS OF 12 TO 24 INCHES. * TIMING...SNOW WILL CONTINUE THROUGH EARLY SUNDAY MORNING. * TEMPERATURES...MID 20S. * WINDS...10 TO 20 MPH WITH GUSTS OF 25 MPH. PRECAUTIONARY/PREPAREDNESS ACTIONS... A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO POSSIBLE. CONDITIONS WILL DETERIORATE VERY RAPIDLY TODAY MORNING AND WILL MAKE TRAVEL EXTREMELY TREACHEROUS. && $$ BAJ ------- Link to comment Share on other sites More sharing options...
Jeb Posted December 25, 2009 Author Report Share Posted December 25, 2009 000 FXUS61 KLWX 182025 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 325 PM EST FRI DEC 18 2009 .SYNOPSIS... -- Changed Discussion -- LOW PRESSURE OVER THE SOUTHEASTERN STATES WILL INTENSIFY ALONG THE CAROLINA COAST THIS EVENING. THE STORM WILL INTENSIFY AND MOVE ALONG THE EAST COAST SATURDAY INTO SUNDAY MORNING. A WEAK DISTURBANCE WILL CROSS THE MID-ATLANTIC REGION LATE MONDAY BEFORE HIGH PRESSURE BUILDS IN FOR THE MIDDLE PART OF THE WEEK. A STRONG UPPER DISTURBANCE IS EXPECTED TO IMPACT THE MID-ATLANTIC FOR CHRISTMAS. -- End Changed Discussion -- && .NEAR TERM /THROUGH TONIGHT/... -- Changed Discussion -- ACCUMULATING SNOWFALL BEGINS THIS AFTERNOON. REGIONAL RADAR MOSAIC DEPICTS THE LEADING BANDS OF SNOW CURRENTLY STRETCHED FROM SOUTHERN WV TO CAPE HATTERAS...INCLUDING HIGHLAND...AUGUSTA AND NELSON COUNTIES. A FEW FLAKES MAY REACH DC AND BALTIMORE THIS EVENING...BUT ACCUMULATING SNOW WILL BE A FEW HOURS LATER GIVEN SURFACE AND AIR TEMPERATURES IN THE LOW 30S. GENERAL OVERNIGHT ACCUMULATIONS OF 2-4 INCHES WILL BE POSSIBLE IN THE METRO AREAS...5-10 INCHES IN THE CENTRAL SHENANDOAH VALLEY AND CENTRAL FOOTHILLS. -- End Changed Discussion -- && .SHORT TERM /SATURDAY/... -- Changed Discussion -- INTENSE SNOWFALL BEGINS THIS EVENING FOR SW ZONES THEN SPREADS NORTHEAST THROUGH THE NIGHT AS THE CENTER OF THE LOW REACHES THE GA COAST AND INTENSIFIES AS IT HEADS NE UP THE CAROLINA COAST TONIGHT. EXPECTING THE STORM TO BE HALF OVER FOR THE SW ZONES BY TOMORROW MORNING...WHILE JUST GETTING UNDERWAY FOR THE BALTIMORE- DC METRO AREA. AS THE SYSTEM CROSSES CAPE HATTERAS EARLY SATURDAY... WRAPAROUND SNOW BANDS SPREAD ACROSS THE CWA...PRIMARILY ALONG AND EAST OF THE SHENANDOAH VALLEY. A TROWAL WITH EMBEDDED INSTABILITY EXPECTED TO BE ALONG THE I-95 CORRIDOR THROUGH THE DAY SATURDAY... PRODUCING INTENSE SNOWFALL. THE TROWAL AXIS PULLS EAST SATURDAY NIGHT...THOUGH THE RATE AT WHICH IT MOVES EAST REMAINS TO BE SEEN. HOWEVER...EXPECT SNOWFALL TO TAPER OFF FROM WEST TO EAST SATURDAY NIGHT...ENDING ALONG THE WESTERN SHORE OF THE BAY SUNDAY MORNING. WINDS OF 15 TO 20 MPH WITH GUSTS TO 25 MPH WILL BLOW THE HEAVY SNOW AS IT FALLS...FURTHER DECREASING VISIBILITY. TRAVEL WILL BE VERY TREACHEROUS AND IS GREATLY DISCOURAGED LATE TONIGHT THROUGH SATURDAY. -- End Changed Discussion -- && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... -- Changed Discussion -- SNOW XPCD TO TAPER OFF SUN AS LOPRES MOVES QUICKLY AWAY FROM RGN. WNWLY LOW-LVL FLOW AND APRCH OF A LOW-AMPLITUDE SHRTWV TROF WILL PROMOTE UPSLP SNOW SHOWERS ALONG WRN SLOPES OF ALLEGHENY FRONT THRU MON NGT. COLD AIR RMNS PRESENT THRU MUCH OF NEXT WEEK OWING TO PERSISTENT SNOW PACK. A STRONG CLOSED UPR LOW XPCD TO FORM OVER SRN PLNS MID WEEK AND COULD RESULT IN PCPN THU-FRI. ATTM...MODELS SUGGEST A TRANSITION FROM SNOW INITIALLY TO RAIN AS WARM AIR IS DRAWN INTO THE SYSTEM. -- End Changed Discussion -- && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... -- Changed Discussion -- VFR CONDITIONS END THIS EVENING AS SNOW SPREADS NORTHEASTWARD. SNOW INTENSIFIES FROM SW TO NE TONIGHT WITH HEAVY SNOW ALL DAY SATURDAY BEFORE TAPERING OFF FROM SW TO NE SATURDAY NIGHT. NLY WINDS 15 KT WITH GUSTS UP TO 25 KT DURING SNOWFALL SATURDAY. MAIN PSBLTY FOR TERMINAL IMPACTS IN EXTENDED PDS IS THU-FRI NEXT WEEK...WHEN A DEEP CLOSED UPR LOW WILL APRCH APLCNS AND COULD GENERATE RAIN/SNOW OVER MUCH OF MID-ATLC RGN. -- End Changed Discussion -- && .MARINE... -- Changed Discussion -- EASTERLY FLOW INCREASES THIS AFTERNOON WITH SCA STARTING SOUTH THIS EVENING AND EXPANDING TO ALL WATERS BY MIDNIGHT. INTENSIFICATION CONTINUES THROUGH THE NIGHT WITH GALES EXPECTED ACROSS THE WATERS EXCEPT THE TIDAL POTOMAC ABOVE COBB ISLAND...THE PATAPSCO...AND NORTH OF POOLES ISLAND. GALE FORCE GUSTS AND HEAVY SNOW ARE EXPECTED SATURDAY AND SATURDAY NIGHT BEFORE THE STORM PULLS AWAY FROM THE BAY SUNDAY MORNING. -- End Changed Discussion -- && .TIDES/COASTAL FLOODING... -- Changed Discussion -- LOW PRESSURE WILL INTENSIFY OFF THE CAROLINA COAST TONIGHT...MOVING NEAR THE MOUTH OF THE BAY LATE TONIGHT AND SATURDAY. PROLONGED NORTHEASTERLY FLOW WILL BUILD EXCESS WATER INTO THE BAY...BRINGING POSITIVE TIDAL DEPARTURES OF AROUND ONE FOOT TONIGHT AND SATURDAY. NO COASTAL FLOODING IS EXPECTED. -- End Changed Discussion -- && .LWX WATCHES/WARNINGS/ADVISORIES... DC...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR DCZ001. MD...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR MDZ003>007-009>011-013-014-018. WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 AM EST SUNDAY FOR MDZ016-017-501-502. VA...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR VAZ042-053-054. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR VAZ021-025-026-036>039-050-056. WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 AM EST SUNDAY FOR VAZ027>031-040-041-051-052-055-057. WV...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR WVZ051>053. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR WVZ054. WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 AM EST SUNDAY FOR WVZ050-055-501>504. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST SATURDAY FOR ANZ531-532-539-540. GALE WARNING FROM 6 AM TO 10 PM EST SATURDAY FOR ANZ531>534- 537-539>543. SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST SATURDAY FOR ANZ533-534-537-541>543. SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM EST SATURDAY FOR ANZ530-535-536-538. && $$ BAJ/KRAMAR ----------- Link to comment Share on other sites More sharing options...
Jeb Posted December 25, 2009 Author Report Share Posted December 25, 2009 000 FXUS61 KLWX 190139 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 839 PM EST FRI DEC 18 2009 .SYNOPSIS... -- Changed Discussion -- LOW PRESSURE OVER THE SOUTHEASTERN STATES WILL INTENSIFY ALONG THE CAROLINA COAST OVERNIGHT. THE STORM WILL INTENSIFY AND MOVE ALONG THE EAST COAST SATURDAY INTO SUNDAY MORNING. A WEAK DISTURBANCE WILL CROSS THE MID-ATLANTIC REGION LATE MONDAY BEFORE HIGH PRESSURE BUILDS IN FOR THE MIDDLE PART OF THE WEEK. A STRONG UPPER DISTURBANCE IS EXPECTED TO IMPACT THE MID-ATLANTIC FOR CHRISTMAS. -- End Changed Discussion -- && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... -- Changed Discussion -- CURRENT ANALYSIS SHOWS LOW PRESSURE DEVELOPING ALONG THE SOUTH CAROLINA COAST EARLY THIS EVENING. THIS LOW WILL CONTINUE TO INTENSIFY AS IT SLOWLY MOVES UP THE MID-ATLANTIC COAST OVERNIGHT. AN UPPER-LEVEL LOW IS CURRENTLY MOVING THROUGH THE MIDWEST WHILE HIGH PRESSURE REMAINS OVER NEW ENGLAND PUMPING IN PLENTY OF COLD AIR. SNOW HAS ALREADY BROKE OUT ACROSS THE CENTRAL AND SOUTHERN CWA THIS EVENING WELL AHEAD OF THE SURFACE LOW. PRECIPITATION WILL CONTINUE TO SPREAD NORTH THIS EVENING AND SNOW...HEAVY AT TIMES IS EXPECTED OVERNIGHT ACROSS THE ENTIRE CWA. HAVE BUMPED UP ACCUMULATIONS OVERNIGHT DUE TO BANDING THAT IS ANTICIPATED WITH THE PRECIPITATION. ACCUMULATIONS BY MORNING WILL BE AROUND 4 TO 8 INCHES ACROSS THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS...AND 6 TO 12 INCHES ACROSS THE SHENANDOAH VALLEY INTO CENTRAL VIRGINA INTO THE VIRGINIA PIEDMONT AND LOWER SOUTHERN MARYLAND. -- End Changed Discussion -- && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... -- Changed Discussion -- LOW PRESSURE WILL CONTINUE TO INTENSIFY AS IT MOVES UP THE MID- ATLANTIC COAST SATURDAY. SNOW WILL CONTINUE ACROSS THE ENTIRE CWA...HEAVY AT TIMES. THE HEAVIEST SNOW WILL FALL DURING THE MORNING HOURS WEST OF THE BLUE RIDGE MOUNTAINS AND THROUGH THE AFTERNOON HOURS EAST OF THE BLUE RIDGE MOUNTAINS. WINDS OF 15 TO 20 MPH WITH GUSTS TO 25 MPH WILL BLOW THE HEAVY SNOW AS IT FALLS...FURTHER DECREASING VISIBILITY. TRAVEL WILL BE VERY TREACHEROUS AND IS GREATLY DISCOURAGED THROUGH SATURDAY. -- End Changed Discussion -- && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... SNOW XPCD TO TAPER OFF SUN AS LOPRES MOVES QUICKLY AWAY FROM RGN. WNWLY LOW-LVL FLOW AND APRCH OF A LOW-AMPLITUDE SHRTWV TROF WILL PROMOTE UPSLP SNOW SHOWERS ALONG WRN SLOPES OF ALLEGHENY FRONT THRU MON NGT. COLD AIR RMNS PRESENT THRU MUCH OF NEXT WEEK OWING TO PERSISTENT SNOW PACK. A STRONG CLOSED UPR LOW XPCD TO FORM OVER SRN PLNS MID WEEK AND COULD RESULT IN PCPN THU-FRI. ATTM...MODELS SUGGEST A TRANSITION FROM SNOW INITIALLY TO RAIN AS WARM AIR IS DRAWN INTO THE SYSTEM. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... -- Changed Discussion -- CIGS AND VSBYS WILL RAPIDLY DETERIORATE ONCE SNOW BEGINS THIS EVENING. IFR/SUBIFR CIGS AND VSBYS ARE EXPECTED IN SNOW OVERNIGHT THROUGH SATURDAY. NLY WINDS 15 KT WITH GUSTS UP TO 25 KT DURING SNOWFALL SATURDAY...ESPECIALLY ACROSS THE EASTERN TERMINALS. MAIN PSBLTY FOR TERMINAL IMPACTS IN EXTENDED PDS IS THU-FRI NEXT WEEK...WHEN A DEEP CLOSED UPR LOW WILL APRCH APLCNS AND COULD GENERATE RAIN/SNOW OVER MUCH OF MID-ATLC RGN. -- End Changed Discussion -- && .MARINE... -- Changed Discussion -- LOW PRESSURE DEVELOPING OFF THE SOUTH CAROLINA COAST THIS EVENING WILL SLOWLY MOVE NORTHWARD UP THE MID-ATLANTIC COAST AS IT INTENSIFIES OVERNIGHT AND SATURDAY. THE INCREASING PRESSURE GRADIENT WILL BRING SCA WINDS OVERNIGHT...WITH THE STRONGEST WINDS ACROSS THE CHESAPEAKE BAY AND LOWER TIDAL POTOMAC WHERE GUSTS AROUND 30 KNOTS ARE EXPECTED. AS THE GRADIENT INCREASES...WINDS WILL INCREASE SATURDAY INTO SATURDAY NIGHT ACROSS THE LOWER TIDAL POTOMAC AND CHESAPEAKE BAY FROM POOLES ISLAND TO SMITH POINT. WILL CONTINUE WITH A GALE WARNING ACROSS THESE AREAS...AND SCA CONDITIONS ELSEWHERE. A SMALL CRAFT ADVISORY WILL LIKELY BE WARRANTED FOR THE WATERS OVERNIGHT SATURDAY AND SUNDAY. -- End Changed Discussion -- && .TIDES/COASTAL FLOODING... -- Changed Discussion -- LOW PRESSURE WILL INTENSIFY OFF THE CAROLINA COAST TONIGHT...MOVING NEAR THE MOUTH OF THE BAY SATURDAY. PROLONGED NORTHEASTERLY FLOW WILL BUILD EXCESS WATER INTO THE BAY...BRINGING POSITIVE TIDAL DEPARTURES OF UP TO ONE FOOT ABOVE NORMAL BY SATURDAY. MINOR COASTAL FLOODING IS POSSIBLE NEAR TIMES OF HIGH TIDE SATURDAY. -- End Changed Discussion -- && .LWX WATCHES/WARNINGS/ADVISORIES... -- Changed Discussion -- DC...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR DCZ001. MD...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR MDZ003>007-009>011-013-014-018. WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR MDZ016-017-501- 502. VA...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR VAZ042-053-054. WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR VAZ021-025-026- 036>039-050-056. WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR VAZ027>031-040- 041-051-052-055-057. WV...WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 6 AM EST SUNDAY FOR WVZ051>053. WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ054. WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ050-055- 501>504. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST SATURDAY FOR ANZ531-532-539-540. GALE WARNING FROM 6 AM TO 10 PM EST SATURDAY FOR ANZ531>534- 537-539>543. SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR ANZ533-534- 537-541>543. SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM EST SATURDAY FOR ANZ530-535-536-538. -- End Changed Discussion -- && $$ LASORSA/KRAMAR/BAJ --------------- Link to comment Share on other sites More sharing options...
Jeb Posted December 25, 2009 Author Report Share Posted December 25, 2009 000 FXUS61 KLWX 190858 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 358 AM EST SAT DEC 19 2009 .SYNOPSIS... -- Changed Discussion -- LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL INTENSIFY AND MOVE ALONG THE COAST AND OFF THE DELMARVA TONIGHT AND EAST OF LONG ISLAND SUNDAY MORNING. A WEAK DISTURBANCE WILL CROSS THE MID-ATLANTIC REGION LATE MONDAY BEFORE HIGH PRESSURE BUILDS IN FOR THE MIDDLE PART OF THE WEEK. A STRONG UPPER DISTURBANCE IS EXPECTED TO IMPACT THE MID-ATLANTIC FOR CHRISTMAS. -- End Changed Discussion -- && .NEAR TERM /TODAY/... -- Changed Discussion -- MID ATLC LOOKS ON ITS WAY TO RECORD DEC SNOWFALL - TWO DAY DEC RECORDS FOR MAJOR AIRPORTS: DCA 12.0" 1932 BWI 14.1" 1960 IAD 12.1" 1969 LOW PRES HAS DEEPENED DRAMATICALLY AT HAT BTWN 04 AND 08Z - FM 1004 TO 990 MB...AND WL CONT INTENSIFY AS IT APRCHS THE DELMARVA LATE THIS AFTN/ERLY EVE. BAND OF HVIEST RDR RETURN ALREADY SEEN TO BE PIVOTING TO A MORE NE-SW ALIGNMENT. HVIEST SNOWFALL AREA WL MOVE FM THE CENTRAL SHEN VALLEY UP TOWARDS DC/BALT/NHK...WHERE IT WL CONT TO SNOW HEAVILY THRUT THE DAY. TOTALS NEAR 2` PSBL W OF CHO WHERE 15" WAS REPORTED AT 1 AM...AND BY END OF TNGT NEAR 20" IN THE I-95 CORRIDOR. BLZRD WRNG SE OF DC WL RMN AS IS. THIS IS A REFLECTION OF STRONGER WINDS CLOSE TO THE BAY...NOT HEAVIER SNOWFALL. -- End Changed Discussion -- && .SHORT TERM /TONIGHT/... -- Changed Discussion -- BLV SNOW WL BECOME LGT TNGT IN THE SW...BUT XPCTD TO CONT AT A MDT PACE IN I-95 CORRIDOR DURG THE EVE HRS. TEMPS OVRNGT IN 20S ACROSS THE CWA - WIND CHILLS IN THE TEENS. -- End Changed Discussion -- && .LONG TERM /SUNDAY THROUGH FRIDAY/... SNOW XPCD TO TAPER OFF SUN AS LOPRES MOVES QUICKLY AWAY FROM RGN. WNWLY LOW-LVL FLOW AND APRCH OF A LOW-AMPLITUDE SHRTWV TROF WILL PROMOTE UPSLP SNOW SHOWERS ALONG WRN SLOPES OF ALLEGHENY FRONT THRU MON NGT. COLD AIR RMNS PRESENT THRU MUCH OF NEXT WEEK OWING TO PERSISTENT SNOW PACK. A STRONG CLOSED UPR LOW XPCD TO FORM OVER SRN PLNS MID WEEK AND COULD RESULT IN PCPN THU-FRI. ATTM...MODELS SUGGEST A TRANSITION FROM SNOW INITIALLY TO RAIN AS WARM AIR IS DRAWN INTO THE SYSTEM. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... -- Changed Discussion -- TAFS HV ESSENTIALLY BEEN BURIED IN VLIFR CIGS/VSBYS THRUT THE DAYLGT HRS. ALTHO THERE MAY BE SOME MINOR IMRVMNTS GETTING IN/OUT OF THE THREE MAJOR AIRPORTS WL BE XTRMLY DIFFICULT TDA THRU THIS EVENG. MAIN PSBLTY FOR TERMINAL IMPACTS IN EXTENDED PDS IS THU-FRI NEXT WEEK...WHEN A DEEP CLOSED UPR LOW WILL APRCH APLCNS AND COULD GENERATE RAIN/SNOW OVER MUCH OF MID-ATLC RGN. -- End Changed Discussion -- && .MARINE... LOW PRESSURE NEAR ILM WILL SLOWLY MOVE NORTHWARD UP THE MID- ATLANTIC COAST AS IT INTENSIFIES OVERNIGHT AND SATURDAY. THE INCREASING PRESSURE GRADIENT WILL BRING SCA WINDS OVERNIGHT...WITH THE STRONGEST WINDS ACROSS THE CHESAPEAKE BAY AND LOWER TIDAL POTOMAC WHERE GUSTS AROUND 30 KNOTS ARE EXPECTED. AS THE GRADIENT INCREASES...WINDS WILL INCREASE SATURDAY INTO SATURDAY NIGHT ACROSS THE LOWER TIDAL POTOMAC AND CHESAPEAKE BAY FROM POOLES ISLAND TO SMITH POINT. WILL CONTINUE WITH A GALE WARNING ACROSS THESE AREAS...AND SCA CONDITIONS ELSEWHERE. A SMALL CRAFT ADVISORY WILL LIKELY BE WARRANTED FOR THE WATERS OVERNIGHT SATURDAY AND SUNDAY. && .TIDES/COASTAL FLOODING... -- Changed Discussion -- PROLONGED NORTHEASTERLY FLOW WILL BUILD EXCESS WATER INTO THE BAY. ATTM TIDAL LVLS AT DC/BALT/ANNA HAVEN`T BUDGED FM NRML...BUT POSITIVE TIDAL DEPARTURES OF UP TO ONE FOOT ABOVE NORMAL ARE POSSIBLE TODAY. -- End Changed Discussion -- && .LWX WATCHES/WARNINGS/ADVISORIES... -- Changed Discussion -- DC...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR DCZ001. MD...WINTER STORM WARNING UNTIL 6 AM EST EARLY THIS MORNING FOR MDZ013-014-016>018. WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR MDZ013-014-016>018. BLIZZARD WARNING UNTIL 6 PM EST THIS EVENING FOR MDZ013-014- 016>018. WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR MDZ003>007- 009>011-501-502. VA...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR VAZ021-025>031- 036>042-050>057. WV...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ050>055- 501>504. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR ANZ531>534-537-539>543. GALE WARNING UNTIL 10 PM EST THIS EVENING FOR ANZ531>534-537- 539>543. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ530- 535-536-538. -- End Changed Discussion -- && $$ PRODUCTS...WOODY!/JRK/BP ----------- Link to comment Share on other sites More sharing options...
Jeb Posted December 25, 2009 Author Report Share Posted December 25, 2009 000 FXUS61 KLWX 191532 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1032 AM EST SAT DEC 19 2009 .SYNOPSIS... LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL INTENSIFY AND MOVE ALONG THE COAST AND OFF THE DELMARVA TONIGHT AND EAST OF LONG ISLAND SUNDAY MORNING. A WEAK DISTURBANCE WILL CROSS THE MID-ATLANTIC REGION LATE MONDAY BEFORE HIGH PRESSURE BUILDS IN FOR THE MIDDLE PART OF THE WEEK. A STRONG UPPER DISTURBANCE IS EXPECTED TO IMPACT THE MID-ATLANTIC FOR CHRISTMAS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... -- Changed Discussion -- LOW PRES INVOF KHSE...989MB...AND WL CONT INTENSIFY AS IT APRCHS THE DELMARVA LATE THIS AFTN/ERLY EVE. BANDS OF HVIEST RDR RETURN ACROSS CENTRAL VIRGINIA HAS NE- SW ALIGNMENT. HVIEST SNOWFALL AREA WL MOVE FM THE CENTRAL SHEN VALLEY UP TOWARDS DC/BALT/NHK...WHERE IT WL CONT TO SNOW HEAVILY THRUT THE DAY. STORM TOTALS 2 TO 2.5 FT INVOF CHO WHERE 16.5 WAS REPORTED AT 9 AM...ALONG THE ALLEGHENY FRONT...AND 1.5 TO 2 FT ALONG THE THE I-95 CORRIDOR. BLIZZARD WARNING EXPANDED TO GREATER I-95 CORRIDOR AND SOUTHERN MARYLAND. PERIODS AND HEAVY SNOW AND GUSTY WINDS ARE EXPECTED THROUGH THE AFTERNOON HOURS OF THE BLIZZARD AREA. SNOW IS STARTING TO TAPER OFF FOR SW ZONES...A FEW BANDS TO CROSS OUT THERE BRINGING A FEW MORE INCHES. MIXED PRECIP FOR LOWER ST MARYS/SOUTHERN CALVERT COUNTY TO TURN TO ALL SNOW THROUGH MIDDAY. PLEASE CHECK CLIMATE SXN FOR TWO DAY DEC SNOW TOTALS. -- End Changed Discussion -- && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/... BLV SNOW WL BECOME LGT TNGT IN THE SW...BUT XPCTD TO CONT AT A MDT PACE IN I-95 CORRIDOR DURG THE EVE HRS. TEMPS OVRNGT IN 20S ACROSS THE CWA - WIND CHILLS IN THE TEENS. && .LONG TERM /SUNDAY THROUGH FRIDAY/... SNOW XPCD TO TAPER OFF SUN AS LOPRES MOVES QUICKLY AWAY FROM RGN. WNWLY LOW-LVL FLOW AND APRCH OF A LOW-AMPLITUDE SHRTWV TROF WILL PROMOTE UPSLP SNOW SHOWERS ALONG WRN SLOPES OF ALLEGHENY FRONT THRU MON NGT. COLD AIR RMNS PRESENT THRU MUCH OF NEXT WEEK OWING TO PERSISTENT SNOW PACK. A STRONG CLOSED UPR LOW XPCD TO FORM OVER SRN PLNS MID WEEK AND COULD RESULT IN PCPN THU-FRI. ATTM...MODELS SUGGEST A TRANSITION FROM SNOW INITIALLY TO RAIN AS WARM AIR IS DRAWN INTO THE SYSTEM. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... -- Changed Discussion -- TAFS CONTINUE TO BE BURIED IN VLIFR CIGS/VSBYS THRUT THE DAYLGT HRS. SNOW THROUGH THE AFTERNOON PERIODS OF HEAVY SNOW WITH BANDED PRECIPITATION. ALTHO THERE MAY BE SOME MINOR IMRVMNTS GETTING IN/OUT OF THE THREE MAJOR AIRPORTS WL BE XTRMLY DIFFICULT THIS EVENG. MAIN PSBLTY FOR TERMINAL IMPACTS IN EXTENDED PDS IS THU-FRI NEXT WEEK...WHEN A DEEP CLOSED UPR LOW WILL APRCH APLCNS AND COULD GENERATE RAIN/SNOW OVER MUCH OF MID-ATLC RGN. -- End Changed Discussion -- && .MARINE... -- Changed Discussion -- LOW PRESSURE NEAR HATTERAS MOVING NE. GRADIENT HAS INCREASED...GALES FOR THE WATERS THROUGH TONIGHT. ANY MIXED PRECIP OVER THE WATER TO CHANGE OVER TO ALL SNOW THIS AFTERNOON. SMALL CRAFT ADVISORY WILL BE WARRANTED FOR THE WATERS SUNDAY THROUGH SUNDAY NIGHT. STRONGER NW WINDS CONTINUE THROUGH MONDAY/MONDAY NIGHT AS HIGH PRESSURE BUILDS ACROSS THE WATERS. -- End Changed Discussion -- && .TIDES/COASTAL FLOODING... -- Changed Discussion -- PROLONGED NORTHEASTERLY FLOW HAS BUILT POSITIVE ANOMALIES INTO THE BAY. ATTM TIDAL LVLS ARE APPROACHING TWO FEET ABOVE PREDICTED FOR LOWER TIDAL POTOMAC AND LOWER PORTIONS OF THE MD CHES BAY. A COASTAL FLOOD ADVISORY WILL GO UP FOR CALVERT..ST MARYS...CHARLES...KING GEORGE COUNTIES SOON. POSITIVE TIDAL DEPARTURES OF UP TO ONE FOOT ABOVE NORMAL ARE POSSIBLE REST OF THE WATERS TODAY. -- End Changed Discussion -- && .CLIMATE... -- Changed Discussion -- MID ATLC LOOKS ON ITS WAY TO RECORD DEC SNOWFALL - TWO DAY DEC RECORDS FOR MAJOR AIRPORTS: DCA 12.0" 1932 BWI 14.1" 1960 IAD 12.1" 1969 -- End Changed Discussion -- && .LWX WATCHES/WARNINGS/ADVISORIES... -- Changed Discussion -- DC...WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR DCZ001. BLIZZARD WARNING UNTIL 6 PM EST THIS EVENING FOR DCZ001. MD...WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR MDZ006-007-009>011-013-014-016>018. BLIZZARD WARNING UNTIL 6 PM EST THIS EVENING FOR MDZ006-007- 009>011-013-014-016>018. WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR MDZ003>005-501- 502. VA...WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 AM EST SUNDAY FOR VAZ052>057. BLIZZARD WARNING UNTIL 6 PM EST THIS EVENING FOR VAZ052>057. WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR VAZ021-025>031- 036>042-050-051. WV...WINTER STORM WARNING UNTIL 6 AM EST SUNDAY FOR WVZ050>055- 501>504. MARINE...GALE WARNING UNTIL 6 AM EST SUNDAY FOR ANZ530>543. -- End Changed Discussion -- && $$ UPDATE...BAJ PREVIOUS DISCUSSION...ABW/BPP/JRK --------------- Link to comment Share on other sites More sharing options...
Jeb Posted December 25, 2009 Author Report Share Posted December 25, 2009 000 FXUS61 KLWX 210840 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 340 AM EST MON DEC 21 2009 .SYNOPSIS... -- Changed Discussion -- HIGH PRESSURE WILL BUILD ACROSS THE AREA THROUGH WEDNESDAY. LOW PRESSURE OVER THE LOWER MISSISSIPPI VALLEY WILL MOVE NORTH TOWARDS THE GREAT LAKES ON THURSDAY. A SECONDARY LOW PRESSURE SYSTEM WILL DEVELOP OVER THE SOUTHEAST U.S. EARLY CHRISTMAS DAY...BEFORE MOVING NORTH OF THE REGION ON SATURDAY. THIS SYSTEM WILL BRING A WINTRY MIX OF PRECIPITATION TO THE REGION ON CHRISTMAS EVE...THEN LIKELY CHANGE TO ALL RAIN ON CHRISTMAS DAY. HIGH PRESSURE WILL RETURN NEXT WEEKEND. -- End Changed Discussion -- && .NEAR TERM /UNTIL 6 PM THIS EVENING/... -- Changed Discussion -- MOST TEMPERATURES HAVE DROPPED INTO THE 20S EARLY THIS MORNING ACROSS THE CWA...WITH A FEW LOCATIONS WHERE THE WIND HAS GONE LIGHT/CALM REPORTING TEENS AT 07Z. NO MATTER HOW ONE SLICES IT...TEMPERATURES WERE SUB-FREEZING AND THIS WILL ALLOW ANY SNOW MELT/SLUSH TO RE-FREEZE AND RESULT IN DANGEROUS ICY CONDITIONS THIS MORNING. SPS AND HWO ADDRESS THE HAZARD. NEARLY ZONAL /WEST/NORTHWEST/ FLOW ALOFT WILL CONTINUE TODAY. THIS WILL LEAD TO LOTS OF CLOUDS AND SOME SNOW SHOWERS ACROSS FAVORED WESTERN FACING SLOPES OF THE HIGHLANDS TODAY. AM FORECASTING AROUND AN INCH OF SNOW ACCUMULATION. WOULDNT BE SHOCKED FOR A TWO INCH TOTAL TO BE REPORTED BUT HAVE KEPT AMOUNTS BELOW WINTER WEATHER ADVISORY CRITERIA. UPSLOPE AMOUNTS WILL BE PALTRY ADDITIONS TO EXISTING SNOW PACK FROM SATURDAYS SNOW STORM. MAY HAVE CLOUDS AND EVEN SOME FLURRIES PENETRATE EAST OF THE FAVORED UPSLOPE AREAS INTO WESTERN MARYLAND/EASTERN WEST VIRGINIA TODAY...ESPECIALLY IN LIGHT OF A WEAK WAVE PROPAGATING IN ZONAL FLOW. HOWEVER...NO ACCUMULATION IS EXPECTED. CLOUDS AND SOME SUNSHINE IS EXPECTED EAST OF THE BLUE RIDGE. PREFER THE LOWER SET OF MOS GIVEN SNOW PACK AND SOME CLOUD COVER TODAY. -- End Changed Discussion -- && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/... -- Changed Discussion -- UPPER FLOW REMAINS NEARLY CONSTANT TONIGHT...AS WEAK HIGH PRESSURE AT THE SURFACE STARTS TO BUILD ACROSS THE AREA. SNOW SHOWERS WILL BEGIN TO WANE OVER FAVORED UPSLOPE LOCATIONS. GRADIENT WILL ALSO BE WEAKER SO WINDS WILL BE LIGHTER AND THIS WILL PAVE THE WAY FOR A DECENT RADIATION COOLING NIGHT. IN ADDITION...GIVEN THE SNOW PACK AND ITS ENHANCING EFFECT AT RADIATING LONGWAVE RADIATION...HAVE UNDERCUT MOS BY A FEW DEGREES. WATCH FOR RE-FREEZING OF SLUSH AGAIN. -- End Changed Discussion -- && .LONG TERM /TUESDAY THROUGH SUNDAY/... -- Changed Discussion -- HIPRES RIDGING SWD FROM ONTARIO WILL CONTINUE TO PROVIDE COOL AND QUIET CONDITIONS FOR THE AREA TUE-WED. LEANED TOWARDS COOLER SIDE OF GUIDANCE WITH SNOWPACK IN PLACE...WITH DAILY HIGHS IN THE 30S/LOWS IN THE TEENS TO L20S. PROGRESSIVE FLOW PATTERN MIDWEEK WITH UPPER LOW E OF NEWFOUNDLAND SLOWLY EXITING AND C CONUS RIDGE BUILDING TOWARDS THE ERN SEABOARD. LOPRES OVR THE PAC NW IS EXPECTED TO DIVE SWD TOWARDS THE ROCKIES AND SRN PLAINS BY WED. MODEL GUIDANCE GENERALLY IN AGREEMENT OF THIS SYSTEM PHASING WITH UPSTREAM ENERGY...WHICH WOULD LIFT CYCLONE NWD TOWARDS THE MIDWEST AND WELL W OF THE REGION LATE THIS WEEK. 00Z GFS STILL INDICATES SECONDARY CYCLOGENESIS ALONG THE SE COAST. HIPRES RIDGING FROM SRN CANADA WOULD CREATE A CAD SETUP AS MOISTURE STREAMS NWD AHEAD OF THE LOW...WITH THE POTENTIAL FOR WINTRY PRECIP /PRIMARILY FREEZING RAIN/ AT THE ONSET THU NGT AND FRI MRNG. WITH THE EXPECTED TRACK OF THE MAIN LOW...PRECIP SHOULD TRANSITION TO RAIN AS WARM AIR EVENTUALLY INTRUDES THE AREA. STILL TOO FAR OUT TO PINPOINT QPF AMOUNTS BUT WITH 1-2 INCHES LIQUID EQUIV OF SNOWPACK ON GROUND AND FROZEN SOIL...WOULD HAVE TO MONITOR ANY FLOODING POTENTIAL. COLDER TEMPS EXPECTED FOR THE WEEKEND IN WAKE OF FROPA ON SAT. -- End Changed Discussion -- && .AVIATION /08Z MONDAY THROUGH FRIDAY/... -- Changed Discussion -- WEST/NORTHWEST WIND AT 8-12 KNOTS IS EXPECTED TO PERSIST INTO THE EVENING HOURS...BEFORE LESSENING TO 4-8 KNOTS OVERNIGHT. EXPECT SCT-BKN VFR STRATOCU BY AFTERNOON...DISSIPATING AFTER SUNSET. VFR CONDITIONS AND LGT NWLY WINDS THRU THU. A STORM SYSTEM WILL APPROACH LATE THIS WEEK. WITH A SHALLOW LAYER OF COLD AIR IN PLACE...WINTRY PRECIP...SPECIFICALLY FZRA...IS POSSIBLE AT THE ONSET THU NGT AND ERY FRI BEFORE CHANGING TO ALL RA FRI. -- End Changed Discussion -- && .MARINE... -- Changed Discussion -- WEST/NORTHWEST FLOW EXPECTED TO REACH SCA GUST CRITERIA ACROSS THE LOWER TIDAL POTOMAC RIVER/CHESAPEAKE BAY TODAY...THEN LIKELY PERSISTING ACROSS THE MID CHESAPEAKE BAY INTO EARLY TONIGHT. WINDS SHOULD STAY JUST BELOW SCA LVLS FOR MIDWEEK. HOWEVER GUSTS TO 15 KT POSSIBLE DURING THE DAY TUE AND WED. A STORM SYSTEM APPROACHES LATE IN THE WEEK WITH SCA CONDITIONS POSSIBLE BEGINNING THU NGT. -- End Changed Discussion -- && .CLIMATE... MULTIPLE SNOWFALL RECORDS WERE BROKEN FROM THIS SNOWSTORM AT DCA...BWI...IAD. DAILY SNOWFALL RECORDS FOR DEC 19 WERE SMASHED AT ALL THREE AIRPORTS. THESE DAILY SNOWFALL REPORTS ON DEC 19 ALSO BROKE RECORDS FOR THE MOST SNOWFALL FOR ANY CALENDAR DAY DURING THE MONTH OF DEC. DAILY DECEMBER SNOWFALL (IN INCHES) NEW RECORD OLD RECORD DCA 15.0 11.5 (1932) BWI 20.5 11.5 (1932) IAD 16.0 10.6 (1982) ADDITIONAL CLIMATE TIDBITS FROM THE PAST STORM... DCA... THE 15.0 INCHES OF SNOW MEASURED YESTERDAY WAS THE THIRD HIGHEST DAILY SNOWFALL ON ANY CALENDAR DAY AT WASHINGTON DC SINCE SNOWFALL RECORDS BEGAN IN 1884. THE STORM TOTAL SNOWFALL OF 16.4 INCHES OF SNOWFALL ON DEC 18-19 2009 MARKS THE 6TH HIGHEST TWO-DAY SNOWFALL RECORD FOR WASHINGTON DC...PUTTING IT JUST BELOW THE PRESIDENT/S DAY STORM IN 2003 AND AHEAD OF THE JAN 1996 STORM. FOR THE MONTH SO FAR...A TOTAL OF 16.6 INCHES OF SNOW HAS BEEN RECORDED AT DCA. THIS MAKES IT THE SNOWIEST DECEMBER ON RECORD FOR WASHINGTON DC (PREVIOUS RECORD WAS 16.2 IN 1962). BWI... THE 20.5 INCHES OF SNOW MEASURED YESTERDAY WILL GO DOWN AS THE FIFTH HIGHEST DAILY SNOWFALL ON ANY CALENDAR DAY AT BALTIMORE SINCE SNOWFALL RECORDS BEGAN IN 1893. THE STORM TOTAL SNOWFALL OF 21.0 INCHES OF SNOWFALL ON DEC 18-19 2009 MARKS THE 6TH HIGHEST TWO-DAY SNOWFALL RECORD FOR BALTIMORE. FOR THE MONTH SO FAR...A TOTAL OF 22.2 INCHES OF SNOW HAS BEEN RECORDED AT BWI. THIS MAKES IT THE SNOWIEST DECEMBER ON RECORD FOR BALTIMORE (PREVIOUS RECORD WAS 20.4 INCHES IN 1966). && .LWX WATCHES/WARNINGS/ADVISORIES... -- Changed Discussion -- DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR ANZ531>534- 538>543. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ530- 537. -- End Changed Discussion -- && $$ SYNOPSIS...PELOQUIN/KLEIN NEAR TERM...PELOQUIN SHORT TERM...PELOQUIN LONG TERM...KLEIN AVIATION...PELOQUIN/KLEIN MARINE...PELOQUIN/KLEIN CLIMATE...KLEIN ------ Link to comment Share on other sites More sharing options...
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