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

000
FXUS61 KLWX 142015
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
315 PM EST FRI NOV 14 2014

.SYNOPSIS...
CANADIAN HIGH PRESSURE WILL BUILD INTO THE AREA THROUGH SATURDAY.
THEN PUSHES EAST SUNDAY. A COLD FRONT IS EXPECTED TO MOVE THROUGH THE
REGION MONDAY. COLD HIGH PRESSURE WILL RETURN TO THE AREA FOR THE
MIDDLE OF THE COMING WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
WITH COLD ADVECTION...IT HAS BEEN A BLUSTERY AND CHILLY AFTERNOON.
COLD AIR STRATOCU HAVE ALSO FORMED ACROSS MUCH OF THE CWA FOR PARTLY
SUNNY SKIES AND A FEW FLURRIES WERE EVEN FALLING INTO NORTHEAST
MARYLAND. A FEW FLURRIES MAY CONTINUE INTO NORTHERN/WESTERN MARYLAND
THROUGH SUNSET BUT NO ACCUMULATION IS EXPECTED.

AS HIGH PRESSURE BUILDS IN TONIGHT...THE GRADIENT WILL RELAX AND
THUS WIND GUSTS WILL DIMINISH. COLD ADVECTION WILL WANE BUT AS SKIES
CLEAR RADIATION EFFECTS WILL PROMOTE ANOTHER COLD NIGHT WITH MINIMA
NEAR FREEZING IN DOWNTOWN WASHINGTON/BALTIMORE AND 20S OVER THE
SUBURBS AND PERHAPS SOME TEENS OVER THE HIGHLANDS.

HIGH PRESSURE WILL BE PARKED OVER THE AREA ON SATURDAY. DESPITE
SUNSHINE THE CANADIAN AIR MASS WILL DICTATE MAXIMA SIMILAR TO TODAY.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
CENTER OF BROAD HIGH PRESSURE PUSHES EAST SAT NIGHT WHILE WEAK
RIDGING BRIEFLY BUILDS IN ALOFT. THE PATTERN WILL CONTINUE THE DRY
AND QUIET CONDITIONS HEADING INTO SUN MORNING. WARM AIR ADVECTION
AHEAD OF THE NEXT APPROACHING SYSTEM COMBINING WITH INCREASING CLOUD
COVER WILL HELP IN PUSHING OVERNIGHT LOWS CLOSER TO NORMAL...THOUGH
STILL REMAINING BELOW NORMAL LEVELS.

ATTENTION THEN TURNS TO THE NEXT PCPN MAKING SYSTEM(S) EXPECTED LATE
SUNDAY INTO MONDAY. 12Z MODEL CONSENSUS TRENDING WARMER AND A BIT
SLOWER WITH THE PCPN ARRIVAL. THERE ARE ACTUALLY TWO FEATURES OF
NOTE TO WATCH...LOW PRESSURE FORMING OVER THE CAROLINAS AND PUSH TO
THE NORTH AND EAST AS IT RIDES A STALLED FRONT JUST OFFSHORE. THIS
LOW WILL BRING THE INITIAL PCPN CHC SUNDAY NIGHT. THE SECOND FEATURE
WILL BE AN APPROACHING COLD FRONT AS IT DIPS SOUTH AND SWINGS
THROUGH...HOWEVER THIS WILL BE OF AN ISSUE FOR MONDAY. SO CONCERNING
PCPN CHC...HAVE MAINLY DRY CONDITIONS ON SUNDAY EVERYWHERE EXCEPT
CHC IN THE HIGHER ELEVATIONS OF EASTERN WV FOR LATE AFTN/EVENING. A
WEAK SHORTWAVE MIDDAY COULD TRIGGER LIGHT PCPN OVER EASTERN
WV/WESTERN VA...SO HAVE LOW END SLIGHT CHC FOR SUN AFTN. THE PCPN
SHIELD PUSHES IN FROM THE SOUTH AND WEST OVERNIGHT...WITH LIKELY
POPS BY DAYBREAK MONDAY MORNING EVERYWHERE.

SO HIGH CONFIDENCE IN PCPN OCCURRING. LOWER CONFIDENCE THOUGH ON THE
EXACT P-TYPE AND THE TIMING OF TRANSITIONS...IF THEY OCCUR AT ALL.
WITH THE PAST TWO MODEL RUNS TRENDING WARMER...HAVE CONTINUED WITH
THIS THOUGHT AND HAVE MAINTAINED LIGHT TO MOD RAIN OVER MOST OF THE
AREA. SOUNDINGS HINT AT POSSIBLE SNOW MIXING IN LATE SUN NIGHT OVER
THE HIGHER ELEVATIONS AND POSSIBLY EVEN A PERIOD OF SLEET/FREEZING
RAIN. WITH THE UNCERTAINTY OF THE OVERNIGHT TEMP TREND...ESPECIALLY
WITH 850MB TEMPS ON THE LATEST RUN PUSHING 0 DEGREES EVERYWHERE BY
06Z MONDAY NIGHT...WILL REFRAIN FROM INCLUSION OF SLEET/FZRA BUT
WILL KEEP THE RAIN/SNOW MIX IN.

SURGE OF WAA WILL PUSH TEMPS ON SUNDAY TO THE WARMEST HIGHS EXPECTED
IN THE COMING WEEK...GENERALLY IN THE 40S. SOME ISOLATED AREAS RIGHT
ON THE WATER MAY EVEN REACH 50. PCPN/CLOUD COVER AND WAA WILL KEEP
MOST AREAS ABOVE FREEZING SUNDAY NIGHT...WITH ONLY THE HIGHEST
ELEVATIONS DIPPING INTO THE UPPER 20S/LOWER 30S.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
DEEP SHORTWAVE TROUGH AXIS PIVOTS ACROSS THE OHIO VALLEY MONDAY. AT
THE SURFACE...LOW PRESSURE WILL DEVELOP OVER THE NORTHEASTERN GULF
OF MEXICO AND MOVE NORTHEAST ALONG A FRONTAL ZONE DRAPED ALONG THE
EAST COAST. RIDGE AXIS ALONG THE WESTERN SHORE OF THE CONUS /AS
OPPOSED TO OVER THE INTER MOUNTAIN REGION/ WOULD FAVOR A LOW TRACK
FURTHER WEST WHICH MEANS WARMER AIR WILL BE INVOLVED. AS A RESULT IT
IS APPEARING INCREASINGLY LIKELY THAT THIS WILL BE A PREDOMINATELY
RAIN EVENT FOR THE METRO AREAS. HIGHER ELEVATIONS FURTHER WEST INTO
THE EASTERN WEST VIRGINIA PANHANDLE MAY BE ABLE TO HANG ON TO COLDER
TEMPERATURES...BUT HOW COLD AND FOR HOW LONG REMAINS IN QUESTION. IT
IS THESE AREAS WEST OF THE BLUE RIDGE MOUNTAINS THAT WILL HAVE THE
GREATEST PROBABILITY OF ACCUMULATING SNOW WITH THIS SYSTEM.

A VERY COLD AIRMASS WILL FOLLOW AS THE WAVE OF LOW PRESSURE DEPARTS
TO THE NORTHEAST AND AN ARCTIC FRONT SLIDES OFF THE COAST. MEDIUM
RANGE GUIDANCE IS IN GOOD AGREEMENT WITH THE MAGNITUDE OF THE COLD
AIR...SO PRETTY CONFIDENT TEMPERATURES WILL BE 10 TO 20 DEGREES
BELOW NORMAL DURING THE MIDDLE PART OF NEXT WEEK.

AIRMASS WILL GRADUALLY MODERATE THROUGH THE END OF THE WEEK BUT ARE
EXPECTED TO REMAIN BELOW NORMAL.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
MAIN IMPACT THROUGH THE REST OF THE AFTERNOON IS WIND...GUSTS AOA 20
KT THROUGH SUNSET THEN DIMINISHING GUSTS AND DISSIPATING STRATOCU
THEREAFTER. HIGH PRESSURE BUILDS IN LATE TONIGHT INTO SATURDAY.

VFR CONDITIONS SAT NIGHT-SUNDAY WITH LIGHT SOUTHERLY FLOW. MVFR OR
LOWER CONDITIONS EXPECTED SUNDAY NIGHT AS PCPN MOVES IN.

S FLOW LESS THAN 10 KTS BECOMES W MON EVE. GUSTY W TO NW FLOW 10-20
KTS TUE...SUBSIDING TUE NIGHT-WED. SUB-VFR EXPECTED IN -RA W/ BRIEF
TRANSITION TO OR MIX WITH -SN PSBL MAINLY NEAR MRB. VFR EXPECTED TUE
INTO WED.

&&

.MARINE...
SCA CONTINUES FOR ALL WATERS UNTIL 6 PM WITH 20 TO 25 KT GUSTS.
UPPER BAY/POTOMAC DROP OFF AFTER THEN...BUT CONTINUE SCA FROM SANDY
POINT SOUTH AND ALONG THE LOWER POTOMAC THROUGH THE REST OF THE
NIGHT. WITH HIGH PRESSURE BUILDING IN...WINDS DECREASE FOR
SATURDAY.

SUB-SCA CONDITIONS EXPECTED SAT NIGHT-SUN NIGHT. LIGHT SOUTHERLY FLOW
MONDAY BECOMES WEST TO NORTHWEST AND GUSTY MONDAY NIGHT INTO
TUESDAY WITH SMALL CRAFT ADVISORY GUSTS LIKELY. WINDS/SEAS
DIMINISH TUESDAY NIGHT INTO WEDNESDAY BUT GUSTS OF AROUND SMALL
CRAFT ADVISORY LEVELS WILL REMAIN POSSIBLE THROUGH THE MIDDLE OF
NEXT WEEK.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ530-
     531-535-536-538-539.
     SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR ANZ532>534-
     537-540>543.

&&

$$
SYNOPSIS...BPP
NEAR TERM...BPP
SHORT TERM...SEARS
LONG TERM...DFH
AVIATION...SEARS/BPP/DFH
MARINE...SEARS/BPP/DFH







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