Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 102144
AFDLWX

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

.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE MID ATLANTIC THROUGH FRIDAY. A
STRONG COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT. ARCTIC HIGH
PRESSURE THEN BUILDS IN FOR THE WEEKEND. LOW PRESSURE MAY IMPACT
THE AREA MONDAY AND TUESDAY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
SHORT RANGE MDLS HV BEEN IMPLYING ALL DAY THAT AN AREA OF HIGHER
REF (SNSH?) WL DVLP LATE THIS AFTN/ERLY EVE ACROSS LWR SRN MD. THE
COMPUTERS HV BEEN ADAMANT ABT PAINTING THIS IN THE SAME LOCATION
EVERY RUN HAPPENING AT THE SAME TIME SO PRV SHIFT ADDED LO CHC
POPS TO THE FCST FOR THAT AREA. MD CHART ROAD TEMPS FOR THAT AREA
ARE IN THE M50S SO IT LOOKS DOUBTFUL THAT ANY SN THAT COULD FALL
WOULD FRZ...BUT TEMPS SHOULD DROP QUICKLY NOW THAT SUN IS SETTING.
GIVEN CONTINUED MESO MODEL SUPPORT FOR SNOW SHOWERS...HAVE
INCREASED POPS ACROSS E-C VA AND SOUTHERN MD TO CHANCE FOR EARLY
EVE AND LIKELY LATE EVE. NOT EXPECING ADVISORY LEVEL SNOW BUT
COATINGS ARE APPEARING MORE AND MORE LIKELY ESPECIALLY ALONG THE
WESTERN SHORE OF THE BAY IN SOUTHERN MD.

IN THE W THE UPSLOPE SN MACHINE RMNS ON...ALTHO AT DOLLY SODS CAM
SNFL HAS BEEN WAXING AND WANING. PRSNTLY IT IS SNOWING THERE...
AND BLV THE UPSLOPE RGN SN ACTIVITY WL CONT THRU THE NGT. WINT WX
ADVSRY RMNS IN EFFECT.

THERE IS ALSO A WIND CHILL ADVSRY IN EFFECT FOR HIGHER ELEVS.
MAJORITY OF AREA WL SEE LOWS BLO 20 TNGT...AND HIGHER ELEVS WL SEE
TEMPS FALL INTO THE SINGLE DIGITS. THIS WL TRANSLATE AT HIGHER
ELEVS TO WINDS CHILL BLO NEG 10...SINGLE DIGITS W IF I-95.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/...
CYCLONIC UPR LVL PATTERN OVR THE ERN U.S. WL WKN THU INTO FRI.
SKIES SHOULD SEE PLENTY OF SUNSHINE DURG THU BUT TEMPS WL STILL BE
COLD - HIGHS PRIMARILY A30S.

NO PROBS XPCTD THU NGT W/ HIGH PRES OVR THE AREA. ANOTHER CHILLY
NGT ALTHO WINDS WL BE LGT. LOWS IN THE TEENS XPCT SINGLE DIGITS IN
THE MTNS.

CLDS WL BE ON THE INCRS FRI AHD OF A FNT WHICH WL BE USHERING IN
VERY COLD AIR TO THE RGN. SNSH COULD BE PSBL DURG THE AFTN IN THE
W. HIGHS IN THE M30S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
TWO MAIN CONCERNS FOR FRIDAY NIGHT-SATURDAY AS AN ARCTIC COLD FRONT
SWINGS THROUGH. THE FIRST IS SNOW SHOWERS. THERE WILL BE AN ENHANCED
UPSLOPE COMPONENT AND SEVERAL INCHES OF SNOW WILL BE POSSIBLE. WITH
A DEEP MOIST LAYER...SOME SNOW SHOWERS WILL BE ABLE TO MOVE EAST OF
THE MOUNTAINS AS WELL BUT ACCUMULATIONS LOOK LIGHT/SCATTERED AT THIS
TIME. THE MAIN TIME FRAME FOR THESE WOULD BE FRIDAY NIGHT...BUT
THERE COULD BE A RENEWED CHANCE OF AT LEAST FLURRIES ACROSS THE
NORTHERN TIER SATURDAY WITH DEEP MIXING AND CONVECTIVE CLOUDS. THE
OTHER CONCERN WILL BE INCREASING WINDS AND COLD TEMPS. THE WINDS DO
NOT LOOK TO REACH ADVISORY LEVEL AT THIS TIME (PERHAPS CLOSE IN THE
HIGH TERRAIN)...ALTHOUGH SOME 30-40 MPH GUSTS CERTAINLY POSSIBLE.
HOWEVER...THEY WILL DRIVE WIND CHILL VALUES DOWN. BEHIND THE
FRONT...850 MB TEMPS WILL BE BELOW -20C. LOWS FRIDAY NIGHT WILL BE
IN THE TEENS AND HIGHS SATURDAY ONLY IN THE TEENS AND 20S. THE WIND
CHILLS WILL DROP INTO THE SINGLE DIGITS (BELOW ZERO AT HIGHER
ELEVATIONS) WEST AND TEENS EAST AND STAY THERE THROUGH THE DAY
SATURDAY.

A MAJOR ARCTIC OUTBREAK LOOKS IMMINENT DURING THE SECOND HALF OF THE
WEEKEND. A LARGE AREA OF HIGH PRESSURE ORIGINATING FROM DIRECTLY
OVER THE NORTH POLE WILL BARREL OVER THE EASTERN HALF OF THE NATION
IN THE WAKE OF A COLD FRONT ON SATURDAY. 850 MB TEMPERATURES DROP TO
AROUND -25 C OVERNIGHT SATURDAY NIGHT LIKELY PUSHING LOW TEMPS DOWN
INTO THE SINGLE DIGITS POSSIBLY EVEN INTO THE CITIES...WITH LOWS
BELOW ZERO LIKELY IN THE HIGHER ELEVATIONS. WINDS WILL BE BLOWING AS
WELL AS THE COLD AIR RUSHES INTO THE REGION WITH WIND CHILLS WELL
BELOW ZERO A GOOD BET AREA WIDE.

THE AIRMASS BEGINS TO MODERATE SUNDAY INTO EARLY NEXT WEEK...BUT
ARCTIC AIRMASSES OF THIS CALIBER RARELY GO QUIETLY.
SUBSEQUENTLY...GUIDANCE UNANIMOUSLY HINTS AT A STORM SYSTEM
APPROACHING AS THE COLD AIR RETREATS...BUT DIFFERENCES IN TIMING AND
TRACK/STRENGTH MAKE THE ULTIMATE OUTCOME OF POTENTIAL WINTRY WEATHER
UNCERTAIN ESPECIALLY EAST OF THE BLUE RIDGE MOUNTAINS. WESTERN PARTS
OF THE AREA HAVE THE BEST CHANCE OF AN IMPACTFUL WINTER STORM MONDAY
INTO TUESDAY...WITH MORE UNCERTAINTY TOWARDS THE METRO AREAS WHERE
THE TIMING OF WARMER AIR MOVING IN WILL BE CRUCIAL TO PTYPE. OF
NOTE...THE LARGE ARCTIC HIGH RETREATS TO THE EAST AND SETS UP OVER
THE NORTH ATLANTIC...AS OPPOSED TO THE NORTHEAST OVER SOUTHEASTERN
NEWFOUNDLAND WHICH WOULD BE THE MOST FAVORABLE FOR LOCKING IN COLDER
AIR. THERE IS STILL PLENTY OF TIME FOR CHANGE THOUGH SO THIS SYSTEM
BEARS CLOSE MONITORING ESPECIALLY CONSIDERING POTENTIAL PHASING AND
PLENTY OF MOISTURE AVAILABLE.

&&

.AVIATION /22Z WEDNESDAY THROUGH MONDAY/...
CLDS HV INCRSD IN CVRG THIS AFTN BUT STILL ABV VFR AT ALL SITES.
THERE IS A CHC THAT SNSH COULD DVLP NEAR DCA IN LATE AFTN/ERLY
EVE. NO PROBS XPCTD OVRNGT THRU FRI.

VFR WILL PREVAIL FRIDAY NIGHT-SATURDAY...ALTHOUGH THERE COULD BE A
BRIEF SNOW SHOWER OR PERIOD OF FLURRIES. WINDS WILL INCREASE
MARKEDLY WITH GUSTS TO AROUND 30 KT POSSIBLE LATE FRIDAY NIGHT INTO
SATURDAY.

GUSTY NWLY/NLY FLOW SAT NGT-SUN 10-20 G 30 KT. VFR LKLY.
SUB-VFR PSBL EARLY NEXT WEEK AS LOW PRES APPROACHES. WINDS UNCERTAIN
DEPENDING ON TRACK...BUT PREDOMINATELY ELY.

&&

.MARINE...
LONG TERM SCA IN EFFECT FOR ALL OF THE WATERS.

COLD FRONT PASSES FRIDAY NIGHT WITH INCREASING NW WINDS. WILL
CONTINUE TO FORECAST POTENTIAL GALES FOR SATURDAY...ESPECIALLY ON
THE OPEN BAY.

GALES ARE LIKELY SATURDAY NIGHT INTO SUNDAY MORNING AS
STRONG HIGH PRESSURE SURGES INTO THE AREA. FREEZING SPRAY IS LIKELY
AS WELL GIVEN THE ROBUSTLY COLD AIRMASS THE WINDS WILL BE USHERING
IN. WINDS WILL GRADUALLY DIMINISH BY SUNDAY NIGHT...BEFORE LOW
PRESSURE APPROACHES THE WATERS FROM THE SOUTHWEST EARLY NEXT WEEK.

&&

.TIDES/COASTAL FLOODING...
WATER LVLS HV DROPPED IN WNW FLOW.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
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.
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.

&&

$$
PRODUCTS...WOODY!/ADS/DFH


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