Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Text Only | 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

000
FXUS61 KLWX 290047
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
847 PM EDT THU APR 28 2016

.SYNOPSIS...
A COLD FRONT WILL REMAIN STALLED TO THE SOUTH THROUGH FRIDAY.
WAVES OF LOW PRESSURE WILL RIDE ALONG THE BOUNDARY DURING THIS
TIME. THE BOUNDARY WILL DROP  AS FRONTS AND LOW PRESS SYSTEM
MOVES THROUGH THE MID- ATLANTIC BRINGING SHOWERS INTO THE
REGION... MAINLY SUN INTO MON NIGHT.FARTHER SOUTH SATURDAY...BUT IT WILL
THEN LIFT NORTHWARD CLOSER TO THE REGION AGAIN SUNDAY AND MONDAY
AS ANOTHER WAVE OF LOW PRESSURE MOVES ALONG IT.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A NEARLY STATIONARY BOUNDARY REMAINS DRAPED OVER THE ALLEGHENY
HIGHLANDS INTO SOUTHERN VIRGINIA AND NORTHEASTERN NORTH CAROLINA.
THE BOUNDARY WILL REMAIN NEARLY STATIONARY THROUGH TONIGHT...WHICH
MEANS THAT COOL NORTHEAST WINDS WILL PERSIST OVER THE AREA. MIN
TEMPS WILL RANGE FROM THE LOWER TO MIDDLE 40S ALONG THE MASON-
DIXON LINE TO LOWER AND MIDDLE 50S IN THE CENTRAL SHENANDOAH
VALLEY.

AN ONSHORE FLOW WILL CONTINUE TO CAUSE LOW-LEVEL MOISTURE TO BE
TRAPPED UNDERNEATH THE SUBSIDENCE INVERSION...RESULTING IN LOW
CLOUDS ALONG WITH AREAS OF FOG. WARM AND MOIST AIR WILL CONTINUE
TO OVERRUN THE COOL AIR IN PLACE...RESULTING IN DRIZZLE AND
PERHAPS EVEN LIGHT RAIN. A PERIOD OF STEADIER RAIN IS LIKELY THIS
EVENING FOR MOST AREAS THIS EVENING. THIS IS BECAUSE OF SHOWERS
AND THUNDERSTORMS THAT POPPED UP TO OUR WEST IN THE WARM AIR THIS
AFTERNOON. THE ACTIVITY IS PASSING THROUGH THIS EVENING...AND IT
IS WEAKENING DUE TO THE COOLER AIR BUT STILL PRODUCING PERIODS OF
STEADIER RAIN.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
ZONAL H5 FLOW/ELY SFC FLOW WL CONT INTO FRI...AS S/WV ENERGY
TRACKS EWD N OF CWFA. CHC TO LIKELY POPS PREVAIL...HIEST ACROSS
THE NORTHERN HALF OF THE CWA. DONT BELIEVE PCPN WL BE ALL THAT
MEANINGFUL.

WL HV WEAK RDGG IN THE WAKE OF THE S/WV FRI NGT. THIS IS THE BEST
CHC AT A DRY PD FOR THIS FCST CYCLE. AFTER LINGERING EVNG POPS...
PRESERVED 10 POPS/PATCHY DZ WORDING FOR THE OVNGT HRS.

WAA/ISENT LIFT IMPRV SAT-SAT NGT AS AN AMPLIFIED TROF AXIS IN THE
SRN PLAINS EJECTS TWD CWFA. POPS WL BE STAIR-STEPPED UPWD AS THIS
FORCING APPROACHES. LKLY SHRA BY SAT NGT. IT CUD BE ERLR PENDING ANY
TIMING ADJUSTMENTS IN LATER GDNC RUNS.

CWFA WL REMAIN ON THE COOL SIDE OF THE STALLED BNDRY THRUT THIS PD.
TEMPS REFLECT A MDL BLEND/PERSISTENCE TYPE FCST...WHICH CAPTURE THE
LACK OF DIURNAL RANGE.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
LOW PRESS OVER THE OHIO VALLEY AND ITS ASSOCIATED WARM FRONT WILL
BE LIFTING NORTH ON SUN... MOVING ACROSS THE REGION AND BRINGING
SHOWERS TO OUR CWA. THE LOW PRESS WILL TRACK EAST AND MOVE OFF OF
THE MID-ATLANTIC COAST SUN NIGHT INTO EARLY MON... WITH ITS
ASSOCIATED COLD FRONT. GUIDANCE DIFFERS ON TUE TO WED NIGHT
CONDITIONS... WITH GFS BEING DRIER... BUT BRINGING SHOWERS DUE TO
A SHORTWAVE TROUGH ON TUE... WHILE EURO KEEPS A BOUNDARY STALLING
TO OUR SE AND WAVES OF LOW PRESS MOVING THROUGH IT... THEREFORE
KEEPING MAINLY THE SOUTHERN PART OF OUR CWA WITH HIGHER CHANCES OF
PRECIP. COLD FRONT APPROACHES ON THU. TEMPS WILL BE NEAR OR
SLIGHTLY BELOW NORMAL.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
IFR CONDITIONS ALONG WITH PERIODS OF DRIZZLE AND EVEN SOME RAIN AT
TIMES WILL CONTINUE TONIGHT. MVFR CONDITIONS STILL PERSIST
ACROSS KBWI AND KMTN THIS EVENING DUE TO SOME DRIER AIR.
HOWEVER...IFR CONDITIONS ARE EXPECTED TO DEVELOP ACROSS THESE
AREAS OVERNIGHT. THE IFR CONDITIONS WILL PERSIST THROUGH MOST OF
FRIDAY...BUT MAY LIFT TO MVFR LEVELS SOMETIME FRIDAY AFTERNOON
INTO EARLY FRIDAY EVENING. MORE IFR CONDITIONS ARE EXPECTED
FRIDAY NIGHT. PERIODS OF DRIZZLE AND POSSIBLE LIGHT RAIN ARE
POSSIBLE DURING THIS TIME. FRI NGT MAY END UP BEING THE DRIEST
PART OF THIS FCST...BUT THAT MAY ALSO MEAN THE FOG CUD BE THE
DENSEST. BETTER OPPORTUNITY FOR WIDESPREAD RAIN WL OVERSPREAD THE
TERMINALS DURING THE AFTN- EVE SAT.

SUB-VFR CONDITIONS POSSIBLE SATURDAY NIGHT INTO MONDAY MORNING AS
A BOUNDARY REMAINS STALLED NEAR THE AREA AND LOW PRESSURE TRACKS
ALONG IT. THE BOUNDARY WILL PUSH WELL TO OUR SOUTH EARLY NEXT WEEK
AND VFR CONDITIONS MAY RETURN..

&&

.MARINE...
ELY FLOW 10-15 KT ATTM...WHICH WL BE THE MAIN STORY FOR THE NEXT CPL
OF DAYS. DO NOT ANTICIPATE ANY SCA CONDS THRU SAT.

SUB-SCA CONDITIONS EXPECTED DURING THIS
PERIOD AS WINDS WILL BE BELOW CRITERIA. SHOWERS EXPECTED MAINLY SUN
INTO MON NIGHT.

&&

.TIDES/COASTAL FLOODING...
WATER ANOMALIES HAVE BEEN SLOWLY FALLING AND AS HIDE TIDE AS
PASSED...WATER LEVELS HAVE FALLEN BELOW FLOOD STAGE. THE HIDE TIDE
CYCLE THIS EVENING IS NOT EXPECTED TO CAUSE ANY FLOODING
CONCERNS...BUT FRIDAY MORNINGS CYCLE MAY ONCE AGAIN CAUSE MINOR
FLOODING AT ANNAPOLIS .

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...HTS
NEAR TERM...BJL/HTS
SHORT TERM...HTS
LONG TERM...IMR
AVIATION...BJL/IMR/HTS
MARINE...BJL/IMR/HTS
TIDES/COASTAL FLOODING...MJM/BJL



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