Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 101447
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
947 AM EST WED FEB 10 2016

.SYNOPSIS...

LOW PRESSURE OVER NEW ENGLAND WILL PUSH OFF TO THE NORTHEAST.
HIGH PRESSURE WILL BUILD INTO THE MID ATLANTIC THROUGH FRIDAY. A
STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT. ARCTIC HIGH
PRESSURE BUILDS IN FOR THE WEEKEND. LOW PRESSURE MAY IMPACT THE
AREA MONDAY AND TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...

AN UPPER LVL TROUGH WILL SLOWLY LIFT NORTH TDA...ACTING AS THE
FORCING MECHANISM FOR ANY SNOW DEVELOPMENT TODAY INTO TONIGHT.
OUTSIDE OF THE ALLEGHENY FRONT...EXPECTING GENERALLY DRY THRU MID
DAY. FLURRIES BECOME PSBL MAINLY NORTHERN HALF OF THE CWA THIS
AFTN AS THE NEXT SHORTWAVE ENERGY TRAVERSES THE REGION. TOTALS
WILL BE LIGHT...AT MOST ANOTHER TENTH TO TWO-TENTHS OF AN INCH.

THE NEXT CONCERN WILL BE TONIGHT WITH THE COLDER TEMPS MVG IN ON
THE FIRST OF A FEW CAA SURGES. LOWS DROPPING INTO SINGLE DIGITS TO
LOW 20S. WITH THE SURGE OF COLDER AIR...EXPECTING GUSTS INTO THE
20S AND ISOLATED SPOTS ON THE RIDGES INTO THE 30S. THESE TWO
FACTORS COMBINED WILL PRODUCE BELOW ZERO WIND CHILLS PORTIONS OF
THE POTOMAC HIGHLANDS. A WIND CHILL ADVISORY IS IN EFFECT FOR THE
WESTERN TIER OF COUNTIES AND THE BLUE RIDGE ZONES TO ACCOUNT FOR
WIND CHILLS LESS THAN -10 DEGREES. EVERYWHERE ELSE WILL SEE SINGLE
DIGIT WIND CHILLS.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...

THE UPPER LVL TROUGH CONTINUES TO LIFT NORTH THURSDAY...FINALLY
WEAKENING/MOVING OUT OF THE REGION FRIDAY MORNING. UPSLOPE SNOW
SHOWERS CONTINUE DURING THE DAY...EXPECTING TO TAPER OFF THURS
NIGHT AS A DRIER AIRMASS SETTLES INTO THE REGION. WINDS ALSO BEGIN
TO SHIFT TO THE SOUTH. HAVE SLIGHT CHC POPS RIGHT ALONG THE MASON-
DIXON DURING THE DAY TO ACCOUNT FOR ANY SNOW
SHOWERS/STREAMERS...WITH THE REMAINDER OF THE CWA REMAINING DRY.
TEMPS SHOULD WARM ENOUGH SO THAT THE WIND CHILL ADVISORY WL NOT
NEED TO BE XTND THROUGH THE DAY. WHILE TEMPS THURS NIGHT WILL BE
COLDER THAN TONIGHT...AS HIGH PRESSURE BUILDS INTO THE
REGION...EXPECTING LIGHTER WINDS AND THUS NOT AS LOW WIND CHILLS.
ISOLATED SPOTS MAY REACH CRITERIA LVL...BUT ATTM NOT ANTICIPATING
NEEDING AN ADVISORY.

ZONAL FLOW AND HIGH PRESSURE WILL ALLOW TEMPS TO BE SLIGHTLY WARMER
FRIDAY. DRY WX INITIALLY FRI MORNING...HOWEVER THIS WILL BE SHORT
LIVED AS A SFC TROUGH SETS UP OVER THE WESTERN HALF OF THE
CWA...TRIGGERING SNOW SHOWERS. THIS WILL MOVE EAST DURING THE
DAY...FOLLOWED BY A POTENT COLD FRONT WHICH WILL BRING THE CHC
FOR SNOW SHOWERS FRI INTO FRI NIGHT. WITH SUCH A DRY AIRMASS
HAVING BEEN IN PLACE...THE QUICK PROGRESSION OF THE FRONT LEAVES
LITTLE TIME FOR INCRSG MOISTURE AND THUS SNOW AMTS OUTSIDE OF THE
UPSLOPE REGION LOOK TO BE LITTLE. A COUPLE OF INCHES WILL BE PSBL
WITH UPSLOPE SNOW.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...

STRONG CAA WILL AFFECT CWFA SAT-SAT NGT AS THE TROF AXIS AND
DEEPENING SFC LOW PULLS AWAY FROM AREA. H8 TEMPS PLUNGING BELOW -20C
SUGGEST THAT SFC TEMPS WL BE STRUGGLING TO RISE ABOVE THE LWR-MID
20S...AND LKLY WL BE STAYING IN THE TEENS W OF THE BLURDG. IN
ADDITION...MDL SNDGS LOOK TO BE WELL MIXED...W/ AT LEAST 25-30 KT
AVBL TO TRANSPORT DOWN. FCSTS WL BE CONSERVATIVE...BUT THIS
TEMP/WIND COMBO WL KEEP WIND CHILLS IN THE SINGLE DIGITS MOST OF THE
DAY. NIGHTFALL WL ONLY EXASCERBATE THE SITUATION. MIN-T SINGLE
DIGITS /BLO ZERO MTNS/ AND WINDCHILLS BLO ZERO AREAWIDE. WIND CHILL
ADVYS LKLY FOR THIS TIME PERIOD...AS ALREADY IN HWO.

HIPRES WL BUILD ACROSS THE AREA SUNDAY...WHICH WL AT LEAST REDUCE
THE WINDS. TEMPS STILL QUITE COLD THO...BOTH MAXT AND MIN-T SUN NGT.
WL BE THE RECIPIENT OF RETURN FLOW BY SUN NGT...WHICH WL SPREAD CLDS
BACK ACRS THE AREA. IT ALSO MEANS THAT PCPN WL BE APPROACHING.

MON-TUE LOOKS TO BE A MESSY TIME FRAME...AS SRN STREAM LOPRES TRACKS
ACRS THE CONUS...TRANSFERRING ITS ENERGY TO INDUCE CYCLOGENESIS.
GDNC SOLNS AT ODDS AS TO WHERE THE LOW WL TRACK...WHICH MAKES THE
DIFFERENCE BETWEEN A QUICK DOSE OF PCPN AND A MORE PROLONGED
EVENT...AS WELL AS PTYPE. AT THIS POINT...NEED TO CONSIDER PSBLTY
OF AN INLAND SOLN...WHICH MEANS NO PTYPE CAN BE RULED OUT.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...

VFR CONDITIONS FOR THE TAF PERIOD. INCRSG W WINDS TODAY...SUSTAINED
10-15 KTS WITH GUSTS 20-25 KTS. A BRIEF LULL IN THE GUSTS WILL BE
PSBL 22-03Z WITH INCRSG WINDS AGAIN OVERNIGHT.

VFR CONDITIONS THURS THRU FRI NIGHT. LIGHT SNOW PSBL ON THURS...WITH
MINIMAL RESTRICTIONS. GUSTY NW WINDS...WITH SUSTAINED 15-20 KTS AND
GUSTS 25-30 KTS.

VFR CONDS XPCTD THIS WKND. NW WINDS WL BE PRIMARY OPERATIONAL
CONCERN /ON SAT/ WITH GUSTS WELL INTO THE 20S IF NOT LWR 30S /KTS/.

&&

.MARINE...

SCA IN EFFECT WITH WINDS GUSTING BETWEEN 20-25 KTS ON ALL
WATERS. THE SCA WILL REMAIN IN EFFECT FOR ALL WATERS THRU
THURSDAY...AND THEN ON THE CHESAPEAKE BAY WATERS THURS NIGHT. OCNL
LULLS IN THE WINDS WILL BE PSBL THIS AFTN. WHILE GUSTS GET CLOSER TO
30 KTS THURS MORNING...ATTM THE STRONGEST WINDS IN THE ML ARE 32
KTS. WILL CONTINUE WITH SCA FOR NOW AND LET SUBSEQUENT SHIFTS
DETERMINE IF A GALE WARNING IS NECESSARY.

DEEP MIXING IN NW FLOW SAT-SAT NGT...W/ MEAN LYR WINDS SUGGESTING
THAT GALES WL BE PSBL. HV GRIDS W/IN GLW CRITERIA...SPCLY ON THE
OPEN WATERS. MENTION IN HWO AND MARINE SYNOP.

HIPRES BLDS SUN. DECREASING SPDS WL RESULT...BUT MAY STILL HV SCA
CONDS ON A PORTION OF THE WATERS.

&&

.TIDES/COASTAL FLOODING...

WNWLY FLOW HAS OVERSPREAD THE AREA AND WILL CONTINUE FOR THE NEXT
COUPLE OF DAYS. WHILE THIS WILL AIDE IN PUSHING SOME OF THE EXCESS
WATER OUT OF THE ESTUARY...WE NEED TRUE NW TO CREATE A BLOWOUT.
DON`T THINK THAT IS GOING TO HAPPEN.

WATER LEVELS REMAIN JUST OVER 2 FEET ABOVE ASTRO NORMS ON THE
BAY/LWR TIDAL POTOMAC...AND BELIEVE THIS WILL SLOWLY RECEDE THROUGH
THE DAY AHEAD. AS A RESULT...THE UPCOMING TIDE WILL BE HIGHER THAN
ASTRO PREDICTIONS...AND WILL BE TRIGGERING CAUTION STAGES. ANNE
ARUNDEL/CALVERT/ST MARYS CNTYS CURRENTLY UNDER ADVYS. DO NOT BELIEVE
ADVYS WL BE NECESSARY ELSEWHERE ALONG THE WESTERN SHORE OF THE BAY
THIS CYCLE.

HAVE UPDATED FORECASTS ON THE UPPER TIDAL POTOMAC TO FIT GOING
TRENDS...WHERE TIDAL ANOMALIES ARE RUNNING AROUND 2 1/3 FT ABV
ASTRO PREDICTIONS. THAT SUGGESTS THAT A SOLID MINOR INUNDATION
WILL OCCUR AT HIGH TIDE THIS MORNING. ADVISORIES HAVE BEEN ISSUED
FOR ALEXANDRIA AND DC.

LATEST INDICATIONS SUGGEST THAT THERE MAY ALSO BE MINOR INUNDATION
ISSUES AT ST GEORGES ISLAND ALONG WITH THE UPPER TIDAL POTOMAC ON
THE PM TIDE CYCLE. SINCE OVERALL TRENDS WILL BE FOR DECREASING
LEVELS...WILL BE TAKING IT ONE TIDE CYCLE AT A TIME TO BE ABLE TO
INCORPORATE ONGOING CONDITIONS.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY UNTIL NOON EST TODAY FOR DCZ001.
MD...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST
     THURSDAY FOR MDZ501.
     WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR MDZ501.
VA...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST
     THURSDAY FOR VAZ503-504-507-508.
     WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR VAZ503.
     COASTAL FLOOD ADVISORY UNTIL NOON EST TODAY FOR VAZ054.
WV...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST
     THURSDAY FOR WVZ501-503-505-506.
     WINTER WEATHER ADVISORY UNTIL 6 PM EST THURSDAY FOR WVZ501-503-
     505.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ530>534-
     537>543.
     SMALL CRAFT ADVISORY UNTIL 8 PM EST THURSDAY FOR ANZ535-536.

&&

$$
UPDATE...WOODY!
PRVS...APS/HTS


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