Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 281930 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 230 PM EST WED JAN 28 2015 .SYNOPSIS... DRY AND COLD HIGH PRESSURE WILL LINGER INTO EARLY THURSDAY. A COLD FRONT WILL SWING THROUGH THE REGION LATE IN THE DAY ON THURSDAY. A WINDY AND DRY FRIDAY BEHIND THE COLD FRONT WITH HIGH PRESSURE BUILDING IN FOR SATURDAY. LOW PRESSURE APPROACHES THE REGION SUNDAY AND WILL IMPACT THE REGION SUNDAY AFTERNOON AND OVERNIGHT INTO MONDAY. THE LOW WILL MOVE AWAY FROM THE REGION ON MONDAY...FOLLOWED BY HIGH PRESSURE BUILDING INTO THE REGION TUESDAY AND WEDNESDAY. && .NEAR TERM /THROUGH TONIGHT/... ALTHOUGH THE DAY STARTED OFF W/ A QUICK INCREASE OF TEMPS...IT LEVELED-OFF LATE MRNG W/ ONLY A SLOW CLIMB TO OUR MAX WHICH IS LIKELY OCCURRING HERE IN THE MIDDLE AFTN. DEWPOINTS ACROSS THE AREA ARE STILL IN THE SINGLE DIGITS...NOT IDEAL FOR ANYTHING OTHER THAN A BITING COLD FEEL TO THE AIR. GUSTY WINDS IN THE 20-25MPH RANGE ARE ADDING TO THE DISCOMFORT...THOUGH THEY ARE EXPECTED TO GRADUALLY SUBSIDE FROM THE LATE AFTN HRS THRU THE EVE. PAST SUNSET...WINDS SHOULD BE ONLY A LIGHT NW BREEZE. BY THEN...THE VERY LOW DEWPOINTS WILL AIDE IN ANOTHER SHARP TEMP DROP LATE TONIGHT BACK INTO THE TEENS AND 20S ACROSS THE AREA. LOW LEVEL DECOUPLING OF WINDS AND CLEAR SKIES WILL MAKE CERTAIN THAT THIS OCCURS. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... DENSE HIGH CIRRUS WILL START THE DAY ON THU...W/ A CONTINUED INCREASE IN CLOUD COVER FROM THE WEST OVER THE COURSE OF THE DAY. TEMPS WILL AGAIN GRADUALLY CLIMB BACK INTO THE 20S AND L30S THRU THE MRNG. A COLD FRONT TAILING DOWN FROM A CLIPPER SYSTEM WELL TO OUR NORTH WILL QUICKLY TRUDGE ACROSS THE UPPER MIDWEST OVERNIGHT AND INTO EARLY THU. BY MIDDAY...THIS FEATURE WILL BE ON THE DOORSTEP OF THE CNTRL APLCNS - SLIDING OVER THE HIGHER TERRAIN THRU THE EARLY AFTN HRS. A STRENGTHENING SLY SFC WIND WILL HELP BUMP TEMPS BACK UP INTO THE M-U30S FOR THE SRN HALF OF THE CWA AHEAD OF THE FROPA. NRN MD AND JUST INTO NRN VA WILL STILL BE HANGING ONTO THE NEAR OR SUB- FREEZING SFC TEMPS AS PRECIP APPROACHES FROM THE WEST. PLENTY OF DRY AIR WILL GREET THE INCOMING PRECIP...LIKELY PREVENTING MUCH OF IT FROM REACHING THE SFC UNTIL FROPA TOWARD THE LATE AFTN PERIOD. THE LOWER ATMOS OVER THE NRN HALF OF THE CWA WILL ALLOW FOR A MIX OF RAIN/SNOW - POSSIBLY SLEET - AS THE INITIAL WAVE OF PRECIP ARRIVES. THE NRN TIER OF THE CWA /NRN MD/ WILL LIKELY BE COLD ENOUGH FOR MAINLY SNOW W/ SOME LIQUID MIXED-IN AND THIS IS ALSO WHERE THE BEST POTENTIAL FOR SNOW ACCUMULATION WILL BE...ALBEIT VERY LIGHT. A RAIN SNOW MIX POSSIBLE ACROSS THE TIER OF COUNTIES ON EITHER SIDE OF THE I-66 CORRIDOR AND MUCH OF THE POTOMAC HIGHLANDS/BLUE RIDGE. THE FRONT LOOKS TO BE PROGRESSIVE...SO PRECIP CHANCES MAY BE LIMITED TO THIS BAND AND CONDITIONS WILL LIKELY DRY OUT BEHIND THE BOUNDARY - MINUS THE APLCNS. THE HIGHER TERRAIN WILL THEN BECOME THE FOCUS OF MULTI-PERIOD UPSLOPE SNOW SHOWERS W/ POTENTIAL ADVISORY SNOWS FOR THESE HIGHER ELEVATION AREAS ALONG THE SPINE OF THE CNTRL APLCNS. AN AMPLIFIED TROUGH WILL BE ACROSS THE MID-ATLANTIC FRIDAY WHILE THE COLD FRONT WILL BE WELL OFF THE EAST COAST. PVA AND A COLD POOL ALOFT MAY LEAD TO LIGHT SNOW SHOWERS AND FLURRIES ACROSS THE NORTHERN MID-ATLANTIC THROUGH FRIDAY AFTERNOON. NW WINDS WILL BE BLUSTERY WITH GUSTS UP TO 40 MPH FRIDAY. HIGHER WIND GUSTS WILL BE POSSIBLE ACROSS HIGHER ELEVATIONS ALONG AND WEST OF THE BLUE RIDGE AND ACROSS NORTHERN MARYLAND. A WIND ADVISORY MAY BE WARRANTED FOR THESE AREAS DURING THIS TIME. COLD CONDITIONS ARE EXPECTED FRIDAY WITH MAX TEMPS REACHING THE LOW 20S ACROSS HIGHER ELEVATIONS TO THE LOW 30S ALONG I-95. DUE TO GUSTY WINDS...WIND CHILL VALUES WILL BE IN THE TEENS TO 20S. GUSTY NW WINDS WILL CONTINUE FRIDAY NIGHT BUT SUBSIDE SOME WITH GUSTS AROUND 30MPH INTO SATURDAY MORNING. FCST MIN TEMPS SATURDAY MORNING WILL BE IN THE SINGLE DIGITS WEST OF THE BLUE RIDGE TO THE TEENS ELSEWHERE. WIND CHILL VALUES WILL DROP FRIDAY NIGHT AND INTO SATURDAY MORNING. WC ADVISORIES MAY BE WARRANTED NORTH AND WEST OF THE BALT/DC METROS INCLUDING WEST OF THE BLUE RIDGE MTNS. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... SAT...COLD HIGH PRESSURE WILL BE OVER THE MID ATLANTIC REGION TO START THE DAY ON SATURDAY. TEMPS WILL BE SLOWLY REBOUND FROM READING IN THE TEENS EAST OF THE BLUE RIDGE...WHILE WEST OF THE BLUE RIDGE TEMPS WILL RANGE FROM LOWER TEENS AND EVEN SINGLE DIGITS WEST OF I-81. FAIR SKIES ON SATURDAY AHEAD OF THE NEXT STORM SYSTEM. SUN...HIGH PRESSURE WILL SLIDE OFF THE COAST EARLY IN THE DAY. MEANWHILE LOW PRESSURE OVER THE MISSOURI VALLEY WILL HEAD EAST. MOISTURE WILL OVERSPREAD THE REGION AND PRECIPITATION CHANCES INCREASE FROM WEST TO EAST. THE MODELS SHOW SW WINDS ALOFT INCREASING THROUGHOUT THE DAY. HOWEVER TEMPERATURES AT THE SURFACE WILL BE TOUGHER TO ERODE UNDER CLOUDY SKIES. EXPECTING A WINTRY MIX ON SUNDAY. CURRENT TIMING OF PRECIP SUGGESTS THE LATE MORNING TO EARLY AFTERNOON WEST OF THE BLUE RIDGE...AND EARLY TO MID AFTERNOON EAST OF THE BLUE RIDGE. OF COURSE CONFIDENCE OF TIMING PRECIP THIS FAR OUT IS PROBLEMATIC...AND MODEL CHANGE OF ONLY 6 HRS WILL HAVE BIG IMPLICATIONS ON JUST WHAT TYPE OF PRECIP WILL FALL. HOWEVER AM CONCERNED ABOUT COMING OUT OF A 36 HOUR OF SUBFREEZING TEMPS AND MODELS TRYING TO SCOUR OUT THE COLD AIR TOO FAST. THUS ADDED A CHANCE OF FREEZING RAIN FOR ABOUT THE NORTHERN THIRD OF THE CWA. PRECIPITATION WILL CONTINUE INTO THE OVERNIGHT HOURS...ALTHO THE 12Z GFS IS AGGRESSIVE MOVING THE PRECIP OUT QUICKLY SUN NIGHT. MON...LOW PRESSURE WILL MOVING ACROSS THE MASON-DIXON LINE EARLY IN THE DAY BRINGING END TO PRECIP. DAYTIME HIGHS WILL BE BELOW NORMAL BY 4-8 DEGREES-F. THERE COULD BE A SLIGHT CHANCE OF LINGERING SNOW SHOWER ACTIVITY ACROSS THE REGION. TUE-WED...HIGH PRESSURE BUILDS ACROSS THE REGION TUE AND CONTINUES THROUGH WED. TUE WILL BE COLD...ABOUT 10-14 DEGF BELOW NORMAL. TEMPS ON WED MODERATE SOME. SOME GUIDANCE SUGGESTS ANOTHER LOW PRESSURE SYSTEM MOVING OFF THE SE COAST. BUT LOW CONFIDENCE ON THIS FEATURE. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... GUSTY WINDS AND COLD TEMPS THE MAIN WX CONCERN FOR AREA AIRPORTS INTO EARLY THU. CLR SKIES BUT GUSTY WINDS MARK THIS AFTN`S PERIOD...THO GUSTS WILL DROP OFF TOWARD SUNSET. SLY WINDS WILL PICK UP MID-MRNG THU AS A COLD FRONT APPROACHES FROM THE WEST. THE FRONT WILL CARRY A MIX OF RAIN/SNOW FOR A RELATIVELY BRIEF WINDOW OF THE LATE AFTN/EVE AS THE BOUNDARY CROSSES THE REGION. TIMING AND PRECIP- TYPES MAY BECOME MORE CLEAR CLOSER TO THE PASSAGE...WHICH IS TOWARD LATER PART OF THE CURRENT TAF CYCLE. VFR CONDITIONS EXPECTED FRIDAY INTO SATURDAY. GUSTY NORTHWEST WINDS 20-25KTS G 35 KTS ARE EXPECTED FRIDAY. NW WINDS WILL SUBSIDE SOME FRIDAY NIGHT BUT CONTINUE OUT OF THE NW 10-15KTS G20KTS. NW WINDS AROUND 5-10KTS EXPECTED SATURDAY. LOW PRESSURE CROSSES THE REGION SUNDAY AND SUB-VFR CONDITIONS ARE POSSIBLE SUNDAY INTO MONDAY AS A WINTRY MIX IS EXPECTED AT THE TERMINALS. && .MARINE... WIDESPREAD LOW-END SCA CONDS THIS AFTN WILL GRADUALLY SUBSIDE FROM NORTH TO SOUTH INTO THE LATE NIGHT HRS. A BRIEF LULL OVERNIGHT BUT THEN SLY CHANNELING WILL BEGIN LATE THE AFTN THU AHEAD OF A COLD FRONT. THIS BOUNDARY WILL SWING THRU THE AREA LATE THU AFTN/EVE...SWITCHING WINDS BACK TO NWLY WHERE THEY STILL STAY THRU THE END OF THE WEEK. POST-FRONTAL CONDITIONS WILL LEAD TO NW WINDS 20-25KTS WITH GUSTS AROUND 40 KTS FRIDAY AFTERNOON. GALE WARNINGS ARE LIKELY DURING THIS TIME. NW WINDS WILL SUBSIDE SOME FRIDAY NIGHT BUT WINDS SHOULD STAY GUSTY AND GALES OR SCA CONDITIONS ARE LIKELY. NW WINDS WILL SUBSIDE BY SATURDAY. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ530>534- 537>543. SMALL CRAFT ADVISORY FROM 1 PM THURSDAY TO 6 AM EST FRIDAY FOR ANZ530>534-537>543. SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ535- 536. SMALL CRAFT ADVISORY FROM 1 PM TO 6 PM EST THURSDAY FOR ANZ535- 536. && $$ SYNOPSIS...GMS/SMZ NEAR TERM...GMS SHORT TERM...GMS LONG TERM...HAS/SMZ AVIATION...GMS/HAS/SMZ MARINE...GMS/HAS/SMZ

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