Area Forecast Discussion
Issued by NWS Sterling, VA

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298
FXUS61 KLWX 280126 AAA
AFDLWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
926 PM EDT WED APR 27 2016

.SYNOPSIS...
A COLD FRONT WILL REMAIN STALLED NEAR THE VIRGINIA-NORTH CAROLINA
BORDER THROUGH FRIDAY. WAVES OF LOW PRESSURE WILL RIDE ALONG THE
BOUNDARY DURING THIS TIME. THE BOUNDARY WILL DROP FARTHER SOUTH
SATURDAY...BUT ANOTHER WAVE OF LOW PRESSURE WILL TRACK ALONG THE
FRONT SUNDAY NIGHT.

&&

.NEAR TERM /THROUGH THURSDAY/...

LIGHT SHOWERS CONTINUE ACROSS CNTRL VA ALONG 850 MB FRONT. THESE
ARE EXPECTED TO CONTINUE THROUGH THE EVENING WHILE NRN AREAS
REMAIN DRY. OVERNIGHT...850 MB FRONT IS EXPECTED TO START LIFTING
NORTH AS WEAK HEIGHT FALLS AND SFC/850MB WAVE ALONG THE IL/IN
BORDER SPREAD/MOVE EAST. RAIN APPEARS LIKELY EAST AND DEFINITE
WEST AS H85 FRONT TRIES TO LIFT NORTH ACROSS THE REST OF THE FCST
AREA. RAINFALL TOTALS APPEAR IN THE 0.25 TO 0.5 INCH RANGE EXCEPT
HIGHER IN UPSLOPE AREAS. MID-LEVEL DRY SLOT MOVES IN THU NIGHT
WITH MAINLY LOW CLOUDS...DRIZZLE AND FOG.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
PTTN REMAINS UNCHGD THRU THE END OF THE WEEK...AS STALLED FRONT
POISED S OF CWFA. ANY S/WV RIDING ALONG THIS BNDRY CUD TRIGGER A
FEW SHRA. THERE WONT BE MANY SUBSTANTIVE CHGS TO THE FCST GIVEN
THESE SUBTLETIES...AND THE CHALLENGES W/ FORECASTING THEM THIS
FAR OUT.

ONE KEY FEATURE THAT IS DISCERNABLE ATTM IS THE CLOSED LOW ACRS
THE PLAINS OPENS UP AND TRAVERSES THE CONUS DURING THE PD. THE SFC
REFLECTION WL MIGRATE EWD AS WELL...ALONG THE BNDRY... WHICH WL
PROVIDE THE IMPETUS FOR SHRA. THEREFORE WL INCR POPS TO LKLYS THU
MIDDAY THRU MIDNGT.

BYD THAT IT IS UNCLR HOW MUCH MSTR THE SUBSEQUENT VORT WL HV...
EXACTLY WHERE IT WL TRACK...AND HOW STRONG IT WL BE. WL REVERT
BACK TO CHC POPS FOR FRI.

FEW TEMP CHGS DURING THE PD AS WELL. IT WL BE TOUGH FOR MUCH OF MD
TO CRACK 60 DEGF...SPCLY ON THU.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL REMAIN WEDGED ALONG THE EASTERN SLOPES OF THE
APPALACHIAN MOUNTAINS SATURDAY THROUGH SUNDAY. SOME OVERRUNNING
WARMTH AND MOISTURE SATURDAY NIGHT AND AN APPROACHING UPPER LEVEL
DISTURBANCE WILL RIDE ALONG THE OHIO VALLEY INTO OUR REGION AND
BRING A THREAT FOR PERIODS OF RAIN.

PERIODS OF RAIN WILL BECOME MORE PRONOUNCED AND PROLONGED SUNDAY
INTO SUNDAY NIGHT AS THE MAIN UPPER LEVEL TROUGH PIVOTS INTO THE
AREA AND A SURFACE LOW PRESSURE SYSTEM DEVELOPS OVER SOUTHWEST
VIRGINIA.

ADDITIONAL UPPER LEVEL ENERGY WILL ROTATE WITHIN THE MAIN TROUGH OF
LOW PRESSURE MONDAY INTO MONDAY NIGHT...LEAVING THE CHANCE FOR
ADDITIONAL RAIN SHOWERS ACROSS THE REGION.

THE SURFACE LOW AND UPPER ENERGY SHOULD EXIT THE EAST COAST TUESDAY
TO ALLOW FOR A RIDGE OF HIGH PRESSURE TO BUILD INTO THE REGION
TUESDAY NIGHT AND WEDNESDAY. DRIER CONDITIONS ON THE WAY.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
UNSTTLD PTTN THRU THE TAF PD...AND THRU THE END OF THE WK FOR
THAT MATTER. STALLED FRNTL BNDRY S OF THE TERMINALS. ONSHORE FLOW
BRINGING MARINE STRATUS/STCU. WL STICK MAINLY W/ MVFR FLGT CONDS.
CUD BE A FEW SHRA INVOF CHO THIS EVNG...BUT LOW CONFIDENCE. BETTER
CHC AT SEEING SHRA THU PM. PDS OF IFR PSBL TNGT...AND SPCLY THU
AFTN-NGT. HV NOT PLACED AOB IFR IN ANY TAF ATTM.

SHOULD IMPROVE TO VFR ON FRI. VFR CONDITIONS EXPECTED SATURDAY AS
WELL. WINDS NORTHEAST LESS THAN 5 KNOTS. VFR CONDITIONS BECOMING
MVFR OR IFR SATURDAY NIGHT WITH APPROACHING RAIN SHOWERS FROM THE
WEST. WINDS BECOMING SOUTHEAST AROUND 5 KNOTS.

&&

.MARINE...
ONSHORE FLOW WL REMAIN IN PLACE THRU THE END OF THE WEEK INTO THE
WKND. WIND SPDS AOB 10-15 KT THRU THE PD.

&&

.TIDES/COASTAL FLOODING...WATER LEVELS REMAIN ELEVATED ACROSS THE
BAY AND POTOMAC. ONSHORE FLOW IS LIKELY TO RAISE WATER LEVELS
FURTHER WITH MINOR COASTAL FLOODING LIKELY AT ANNAPOLIS...SOLOMONS
AND STRAITS POINT THU MORNING. WILL LEFT NEXT SHIFT EVALUATE.

&&

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

&&

$$
SYNOPSIS...HTS
NEAR TERM...LFR
SHORT TERM...HTS
LONG TERM...KLW
AVIATION...HTS/KLW
MARINE...HTS/KLW
TIDES/COASTAL FLOODING...LFR



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