Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 292057 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 357 PM EST THU JAN 29 2015 .SYNOPSIS... A COLD FRONT WILL SWING THROUGH THE REGION TONIGHT. HIGH PRESSURE BUILDING INTO THE REGION WILL BRING WINDY AND COLD CONDITIONS FRIDAY AND FRIDAY NIGHT. THE HIGH WILL BUILD OVER THE AREA SATURDAY...BUT LOW PRESSURE MAY IMPACT THE AREA LATER SUNDAY INTO MONDAY. COLD HIGH PRESSURE WILL RETURN FOR THE MIDDLE PORTION OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
-- Changed Discussion --
STILL HAVE SEVERAL MESONET OBS SHOWING 31/32 DEG F IN ANNE ARUNDEL...PRINCE GEORGES COUNTIES. WITH PRECIP COMING IN FROM THE WEST AND TEMPS NOT LIKELY TO MOVE ANY HIGHER /IN FACT GIVEN DEWPOINTS THEY COULD DROP A DEGREE OR TWO/...HAVE OPTED TO EXPAND EXISTING WINTER WEATHER ADVISORY EAST TO THE BAY TO INCLUDE MUCH OF THE WASHINGTON METRO AREA FOR A BRIEF PERIOD OF SLEET MIXED WITH POCKETS OF FREEZING RAIN OCCURRING DURING THE EVENING RUSH HOUR. PREV... A WINTRY MIX OF FREEZING RAIN...SLEET AND SNOW IS EXPECTED FOR MUCH OF THE OUTLOOK AREA THIS AFTERNOON AND EARLY EVENING AND THEREFORE A A WINTER WEATHER ADVISORY IS IN EFFECT. HIGH PRESSURE CONTINUES TO MOVE OFF THE CAROLINA COAST THIS AFTERNOON AND SOUTHERLY FLOW HAS INCREASED ACROSS THE REGION. A COLD FRONT IS DRAPED FROM LAKE ERIE TO OH/IN TO KY. AHEAD OF THE COLD FRONT AND IN RESPONSE TO A SHORTWAVE TROUGH AND WAA...PRECIPITATION WILL CONTINUE TO MOVE ACROSS THE APPALACHIAN MTNS AND HIGHLANDS THIS AFTERNOON. A NOSE OF +3 WARM AIR WILL CONTINUE TO MOVE INTO THE REGION AT 850MB. SOUTHERLY FLOW AT THE SFC HAS ALLOWED TEMPS TO CLIMB BUT COLD SURFACES FROM RECENT COLD TEMPS AND SNOWPACK HAS SLOWED THEM FROM CLIMBING MUCH. MANY OBS ARE AOB FREEZING AROUND WASHINGTON DC AND BALTIMORE AND NORTH AND WEST ARE SUCH THAT. SOUTHERLY FLOW AT THE SFC HAS MAINLY ALLOWED TEMPS IN VALLEYS IN CENTRAL FOOTHILLS...PIEDMONT AND SOUTHERN MD TO RISE TO THE MID TO UPPER 30S. THIS TREND WILL CONTINUE AS BOUNDARY LAYER WINDS ARE EXPECTED TO INCREASE TO 10-15KTS. THIS IS A BORDERLINE EVENT SINCE MANY ROAD TEMPS ARE ABOVE FREEZING BUT MESONET OBS ARE NOT. EVEN THOUGH ASOS AND AWOS SITES ARE WELL ABOVE FREEZING...MANY OBS BETWEEN THOSE SITES ARE NOT. THEREFORE...PRECIPITATION MOVING EASTWARD MAY MELT AND FREEZE ON CONTACT ESPECIALLY ON UNTREATED SURFACES. FURTHER NORTH NEAR THE MD/PA BORDER...COLDER TEMPS ALOFT MAY LEAD TO MORE SLEET AND SNOW THAN FZRA BUT ALL FROZEN PTYPES ARE POSSIBLE TODAY. THEREFORE A WINTER WEATHER ADVISORY WAS ISSUED FOR THIS AFTERNOON AND EVENING. THE HRRR HAS BEEN FOLLOWING THE PRECIPITATION RATHER WELL THIS MORNING. ANTICIPATE PRECIPITATION TO BE EAST OF THE WESTERN SHORE OF THE CHESAPEAKE BAY BY 8PM. TEMPS SOUTH OF WASHINGTON DC ARE EXPECTED TO BE ABOVE FREEZING AND THEREFORE RAIN AND SLEET ARE THE MAIN PRECIP TYPES IN THIS REGION. THE FRONT WILL FOLLOW BEHIND AND MOVE ACROSS THE MID-ATLANTIC TONIGHT REACHING THE CHESAPEAKE BAY BY LATE TONIGHT. NW WINDS WILL MOVE IN BEHIND THE FRONT AND UPSLOPE SNOW SHOWERS ARE EXPECTED ACROSS THE WESTERN SLOPES OF THE ALLEGHENY FRONT. SNOW ACCUMULATION IS EXPECTED AS LAPSE RATES STEEPEN IN THE SNOW GROWTH ZONE. A WINTER WEATHER ADVISORY CONTINUES FOR THE WESTERN SLOPES FOR ACCUMULATING SNOW INTO FRIDAY. ACCUMULATION OF 4-8 INCHES ARE POSSIBLE IN THESE LOCATIONS. VORTICITY ADVECTION WILL BE ROTATING AROUND THE MAIN TROUGH TONIGHT AND TOMORROW. DRY WESTERLY WIND EAST OF THE ALLGHENY FRONT SHOULD LIMIT PRECIP FROM REACHING THE GROUND. FCST MIN TEMPS WILL REACH THE 20S IN THE MTNS AND LOW TO MID 30S FROM WASHINGTON DC AND SOUTH AND EAST ALONG I-95.
-- End Changed Discussion --
&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/... HIGH PRES BLDG INTO THE MID ATLC WL LEAD TO A STRNG PRES GRAD ACROSS THE AREA. THIS IN TURN WL LEAD TO A WINDY DAY. BUFKIT X-SXNS ARE SHOWING INXS OF 40 KT A FEW THOUSAND FT OFF THE GRND. THIS WL HV THE PTNL TO BE BROUGHT TO THE SFC. WE ARE ADVSRTSG THE PSBLTY OF A WIND ADVSRY - MOST LKLY AREAS WL BE ABV 1500 FT AND ACROSS THE NRN 1/2 OF THE FCST AREA. HIGHS IN THE LM30S. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... HIGH PRES BLDG OVR THE RNG FRI NGT WL LEAD TO CHILLY TEMPS. LOWS IN THE TEENS ACROSS MUCH OF THE AREA. WINDS WL BE DIMINISHING OVRNGT...BUT W/ COLD TEMPS WINDS CHILLS XPCTD TO BE IN THE SINGLE DIGITS E OF THE MTNS. PRSNTLY SEEING VALUES AS LOW AS -14 IN THE HIGHLANDS. IF THIS TREND CONTS A WIND CHILL ADVSRY WL BE NEEDED FOR OUR FAR WRN AREA. SAT LOOKS TO BE M SUNNY BUT COLD W/ HIGHS RANGING FM THE U20S TO THE MU30S OVR MOST OF THE AREA. SAT NGT WL BE COLD...BUT A LTL WARMER THAN FRI NGT. NO WINDS SO WIND CHILL WL NOT BE A CONCERN. WHAT HAD BEEN A SPLIT IN THE MODELS BETWEEN A LOW TRACK TO OUR NORTH AND ANOTHER TRACK TO OUR SOUTH SEEMS TO BE CONSOLIDATING AROUND THE SOUTHERN TRACK NOW...TAKING IT EAST THRU S VA OR NC. THAT SUPPORTS SNOW FOR MUCH IF NOT ALL OF OUR REGION. WOULD BE PASSING THRU AT A GOOD CLIP BUT ACCUMULATING SNOW CERTAINLY A POSSIBILITY FOR SUN AFTERNOON INTO MONDAY MORNING. HIGH PRESSURE WILL FOLLOW FOR TUE. NEXT COLD FRONT POISED FOR WEDNESDAY. && .AVIATION /21Z THURSDAY THROUGH TUESDAY/... A WINTRY MIX IS EXPECTED THIS AFTERNOON AND EVENING FOR THE TERMINALS. PRECIP WILL MOVE QUICK AND FROM WEST TO EAST THROUGH THE REGION TODAY ENDING ACROSS BWI-MTN-DCA BY 8PM. MVFR CONDITIONS POSSIBLE AT MRB-IAD-DCA-MTN-BWI AS COLDER AIR FURTHER NORTH GIVES A GREATER POTENTIAL FOR SNPL. FURTHER SOUTH..CHO SHOULD STAY RAPL. S WINDS 10-15KTS WILL CONTINUE TODAY AND TONIGHT AHEAD OF A COLD FRONT. A STRONG FROPA IS EXPECTED TONIGHT WITH NW WINDS 20-25KTS G 35-40 EXPECTED LATE TONIGHT AND FRIDAY ACROSS THE TERMINALS. WINDY CONDS FRI AND FRI NGT AS HIGH PRES BLDS INTO THE AREA. NO PROBS XPCTD AVIATION-WISE SAT OR SAT NGT. SNOW AND IFR CONDITIONS ARE POSSIBLE SUNDAY AFTERNOON INTO MONDAY MORNING AS LOW PRESSURE SLIDES BY TO OUR SOUTH. VFR FOR TUESDAY. && .MARINE... A WINTRY MIX WILL MOVE ACROSS THE WATERS THIS EVENING. A MIX OF SNOW SLEET AND RAIN ARE POSSIBLE BUT SHOULD END BY LATE TONIGHT. SOUTHERLY WINDS WILL CONTINUE ON THE WATERS THROUGH TONIGHT BEFORE A STRONG FROPA MOVES ACROSS THE WATERS BY FRIDAY MORNING. NW WINDS 20-25KT GUST AROUND 45KTS POSSIBLE. SCA ARE IN EFFECT AND WILL TRANSITION TO A GALE WARNING FRIDAY. A GALE WRNG IS IN EFFECT FM FRI MRNG THRU THE ERLY HRS OF SAT MRNG..AND THEN AN SCA WL LKLY GO INTO EFFECT AFTRWARDS FOR THE RMNDR OF THE NGT. WINDS WL BE DIMINISHING FOR SAT AND SAT NGT. GUSTY WINDS AND A SMALL CRAFT ADVISORY ARE POSSIBLE ON MONDAY INTO MONDAY NIGHT AS LOW PRESSURE INTENSIFIES OFFSHORE. && .LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...WINTER WEATHER ADVISORY UNTIL 9 PM EST THIS EVENING FOR DCZ001. MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ003- 502. WINTER WEATHER ADVISORY UNTIL 9 PM EST THIS EVENING FOR MDZ004>006-011-013-014-503>508. WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR MDZ501. VA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR VAZ027- 028-030-031-504. WINTER WEATHER ADVISORY UNTIL 9 PM EST THIS EVENING FOR VAZ052>054-501-505-506. WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR VAZ503. WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ050>053-055-502-504-506. WINTER WEATHER ADVISORY UNTIL NOON EST FRIDAY FOR WVZ501-503- 505. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ530>534- 537>543. GALE WARNING FROM 6 AM FRIDAY TO 1 AM EST SATURDAY FOR ANZ530>543. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ535- 536.
-- End Changed Discussion --
&& $$ BPP/HAS/WOODY!/CAS

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.