Area Forecast Discussion


268 
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