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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 271545 AAA AFDLWX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1045 AM EST SAT DEC 27 2014 .SYNOPSIS... HIGH PRESSURE WILL REMAIN ACROSS THE MID-ATLANTIC TODAY...BEFORE MOVING EAST OF CAPE HATTERAS TONIGHT. A COLD FRONT WILL STALL ACROSS THE REGION EARLY SUNDAY...THEN LOW PRESSURE WILL MOVE ALONG THE STALLED FRONT SUNDAY AFTERNOON AND EVENING. ANOTHER LOW PRESSURE SYSTEM WILL MOVE ACROSS THE CAROLINAS MONDAY AND MONDAY NIGHT...FOLLOWED BY HIGH PRESSURE BUILDING INTO THE REGION ON TUESDAY...AND REMAINING THROUGH THE REMAINDER OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
SKIES CLEARING OUT AGAIN BEHIND THE WEAK UPPER SHORTWAVE PASSAGE. THIS FEATURE BROUGHT SOME MID CLOUD DECKS EARLIER THIS MORNING THAT ARE NOW DISSIPATING OVER SRN MD/VA PIEDMONT. A FEW MORE HRS OF SUN INTO THE AFTN...THEN THE BEGINNINGS OF YET ANOTHER MULTI- DAY RAIN EVENT FOR THE MID-ATLC. CIRRUS AND MID CLOUD DEBRIS FROM THE INCOMING LOW PRESSURE SYSTEM WON`T ARRIVE UNTIL LATER THIS AFTN/EVE. TEMPS ATTM STILL FAIRLY MODERATED BUT EXPECTING HIGHS TODAY TO STILL APPROACH 60F IN THE LOWER SHEN VLY/NRN VA PIEDMONT W/ M-U50S ELSEWHERE BUT STILL A FEW DEG BELOW GUIDANCE.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
-- Changed Discussion --
AN AREA OF LOW PRESSURE WILL BE TRACKING FROM THE GREAT LAKES INTO QUEBEC TONIGHT. THE TRAILING COLD FRONT WILL BE APPROACHING THE APPALACHIANS BUT BEGIN TO LOSE STEAM AS IT RUNS INTO THE UPPER LEVEL RIDGE AND BECOMES PARALLEL TO THE UPPER FLOW. FORCING AND MOISTURE WILL BE LIMITED...WITH A CHANCE OF SHOWERS REACHING THE WRN RIDGES AFTER MIDNIGHT. WITH CLOUD COVER...WAA AND INCREASING LOW LEVEL MOISTURE...TEMPERATURES SHOULD HOLD ABOVE FREEZING AND THUS ELIMINATE ANY PTYPE ISSUES. A WAVE OF LOW PRESSURE ORIGINATING FROM THE GULF COAST WILL TRACK ALONG THE FRONT AND BRING THE HIGHEST PROBABILITY OF RAIN TO THE ENTIRE AREA ON SUNDAY. TIMING MAY BE A HAIR QUICKER THAN THE PREVIOUS FORECAST...BUT THE HIGHEST POPS STILL RESIDE IN THE AFTERNOON. DESPITE PWATS INCREASING TO AROUND AN INCH...FORCING IS RATHER SCANT...AND IT APPEARS MOST AREAS WILL RECEIVE LESS THAN A QUARTER INCH OF RAINFALL. TEMPERATURES DURING THIS STAGE OF THE FRONT WILL UNDERGO MORE INFLUENCE ALOFT THAN AT THE SFC...WITH HIGHS SUNDAY EXPECTED IN THE UPPER 40S TO LOWER 50S...POSSIBLY A LITTLE COOLER IN THE NW DEPENDING ON TIMING OF FROPA.
-- End Changed Discussion --
&& .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... MODELS LOOK VERY COINCIDENT ON SUNDAY NIGHT HAVING HIGH POPS...HOWEVER THE GFS HAS SUBSTANTIALLY MORE QPF. BOTH MODELS DROP THE QPF SOUTH THROUGH THE CWA ON MONDAY...WITH DECREASING POPS DURING THE DAYLIGHT HOURS MONDAY. HOWEVER...MONDAY NIGHT THE 00Z ECMWF AND THE 00Z GFS DIVERGE ON THEIR QPF...WITH THE GFS HAVING MORE QPF. BOTH MODELS HAVE LOW PRESSURE MOVING FROM THE SE U.S ACROSS THE CAROLINAS...BUT THE GFS THROWS THE PCPN SHIELD ALL THE WAY BACK WEST OF THE BLUE RIDGE INTO THE COLD AIR. I AM DISCOUNTING THIS SOLN AND WILL GO WITH THE ECMWF QPF WHICH PAINTS THE HEAVIEST QPF ACROSS SOUTHERN VIRGINIA. POPS BELOW CLIMO WILL COMMENCE TUE NIGHT AND CONTINUE THROUGH THE END OF THE WORK WEEK...WITH THE PERIOD TUESDAY NIGHT THROUGH WEDNESDAY NIGHT BEING BELOW CLIMO FOR MIN TEMPS AND MAX TEMPS ON WED. OTHERWISE LOOKS LIKE A FAIRLY SEASONABLE LATE DECEMBER WEEK FOR BOTH TEMPS AND PCPN...WITH NEW YEARS EVE A FEW DEGREES COLDER THAN NORMAL BUT DRY...AND NEW YEARS DAY REMAINING DRY WITH NEAR NORMAL DAYTIME MAX TEMPS. && .AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
HIGH PRESSURE WILL SLIDE OFFSHORE TODAY. VFR EXPECTED THROUGH TONIGHT...WITH MID/HIGH LEVEL CIGS LOWERING LATE TONIGHT. WINDS LIGHT/VRB...BECOMING MORE PRONOUNCED OUT OF THE SOUTH BY THIS AFTERNOON/EVENING BUT REMAINING LESS THAN 10 KT. SUNDAY...MVFR/IFR AT TIMES WITH LOW CLOUDS AND RAIN. COLD FRONT PASSES...VEERING WINDS TO THE NORTH. SUNDAY NIGHT AND MONDAY THE TERMINALS WILL SEE CONTINUED MVFR CONDITIONS DUE TO LOW CIGS AND VSBYS...IMPROVING ON TUE.
-- End Changed Discussion --
&& .MARINE... HIGH PRESSURE WILL BRING CONTINUED LIGHT WINDS ACROSS THE WATERS TODAY. AS THE HIGH MOVES OFFSHORE TONIGHT...WINDS WILL BECOME SOUTHERLY BUT SHOULD REMAIN LESS THAN SCA LEVELS. LOW PRESSURE AND A COLD FRONT WILL BRING RAIN ON SUNDAY...BUT STABLE CONDITIONS WILL KEEP WINDS LIGHT. WINDS MAY APPROACH SCA CONDITIONS DURING DAYLIGHT HOURS WED AND THU. && .EQUIPMENT...
-- Changed Discussion --
KLWX WSR-88D WILL REMAIN OUT OF SERVICE UNTIL AT LEAST LATER TODAY AS REPAIR PARTS AND TECHNICIANS ARE EXPECTED TO ARRIVE LATER THIS MORNING.
-- End Changed Discussion --
&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ UPDATE...GMS PREV DISCUSSION...ADS/LEE

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