Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 190140
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
940 PM EDT SAT APR 18 2015

.SYNOPSIS...
HIGH PRESSURE CENTERED OVER THE UPPER GRATE LAKES WILL TRACK
TOWARDS THE EAST COAST TONIGHT THROUGH SUNDAY. LOW PRESSURE
DEVELOPING IN THE GULF OF MEXICO WILL TRACK NORTHEAST INTO THE MID
ATLANTIC SUNDAY NIGHT. A COLD FRONT MOVE THROUGH THE AREA LATE
MONDAY. AN UPPER LOW BRINGS COOLER THAN NORMAL TEMPERATURES TO
THE NORTHEASTERN STATES FOR THE MIDDLE AND LATE PORTION OF THE WEEK.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
SFC HIGH IS CENTERED NE OF LAKE SUPERIOR. HIGH CLOUDS OVERRIDING
THE RIDGE AND OVERSPREADING THE REGION. LOW TO MID 50S FOR THE
SRN PART OF THE FCST AREA....UPR 40S FOR NRN HALF.

DRY WEDGE IN PLACE SUNDAY MORNING. AN INTENSIFYING LOW LIFTING
NORTH FROM LA WL BRING A DEEP PLUME OF GULF MOISTURE INTO THE SERN
STATES SUNDAY. PRECIP WILL BE SLOW TO SCOUR OUT THE DRY WEDGE
SUNDAY. EXPECTATION IS FOR RAIN ONSET FOR LATE MORNING IN SWRN
ZONES...AFTERNOON FOR THE PIEDMONT...AND EVENING FOR BALTIMORE.

SUNDAY NIGHT...SWATH OF MODERATE WITH LOCALLY HEAVY RAIN LIFTS NORTH
AND EAST ACROSS THE CWA. 100 POPS FOR THE CWA. UP TO TWO INCHES
FOR CENTRAL VA FOOTHILLS GIVEN STRONG ELY COMPONENT THAT WILL
ENHANCE ON THE UPSLOPE OF THE ERN SIDE OF THE BLUE RIDGE/TO THE
PIEDMONT. GENERALLY 1.0 TO 1.5 INCHES ELSEWHERE. SIX HOUR FLASH
FLOOD GUIDANCE IS AROUND 1.5 INCHES FOR BALT/WASH URBAN AND THE
CENTRAL VA BLUE RIDGE. FLOOD WORDING IS IN THE HWO.

SLY LLJ OF 50KT AROUND 2 KFT WILL SHIFT NORTH ACROSS OVERSPREAD
GENERALLY EAST OF I-95 LATE IN THE NIGHT. LOW THUNDER THREAT IN THIS
AREA...BUT WITH AMPLE RAIN TO MIX THIS WIND DOWN...THERE IS A LOW
WIND THREAT FOR SRN MD. MIN TEMPS GENERALLY LOW TO MID 50S...UPR
50 FOR SERN PORTIONS OF THE CWA WHERE SLY FLOW PERSISTS ALL NIGHT.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
THE WRM FRNTL SHIELD OF RA WL BE EXITING THE CWFA AT THE START OF
THE PD MON. WL BE CARRYING ELY POPS FOR ANY LINGERING SHRA.
AFTER THAT...THINK THERE WL BE A DRY/RELATIVELY QUIET PD. WHAT
HAPPENS DURING THIS TIME WL DICATE THE WX FOR THE REST OF THE DAY.
THERE SHUD BE A FAIR AMT OF CLD CVR...LIMITING INSOLATION. THE
AMT WL BE OTRW BE WARM...HUMID /DEWPTS MID-UPR 50S/ AND RELATIVELY
UNSTBL. AM NOTING CAPES ARND 1000 J/KG. SEE ENUF FOR A LINE OF
DIURNALLY DRIVEN SHRA/TSRA AHD OF CFP. QSTN WL BE HOW STRONG WL
THEY BE. EXTENT OF DAYTIME HEATING HOLDS THE KEY. SPC HAS PAINTED
AREA IN MRGL RISK... W/ SLGT RISK IN THE SERN QUAD OF THE CWFA.

FROPA NEAR SUNSET. HV SCALED BACK THUNDER SOON THEREAFTR...AND POPS
DWINDLE THRU THE EVNG. DECENT CAA COMING IN OVNGT...SO HV SCOURED
OUT CLDS AFTR MIDNGT...XCPT FOR THE MTNS.

GDNC CONSISTENT IN GOING WARMER FOR MAXT MON. HV FOLLOWED SUIT...BUT
NOT AS MUCH AS MAV. THAT CUD BE AN ISSUE IF SUNSHINE REALIZED.
SUSPECT THERE MAY BE A QUITE A TEMP GRADIENT ACRS THE AREA. AM NOT
COMFY TRYING TO NAIL EXTREMES AT THIS POINT.  REMOVED NAM FROM MDL
BLEND FOR MIN-T AS IT SEEMS TOO WARM FOR THE EXTENT OF CAA
PROGGED.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
A SLOW-MOVING UPPER LOW OVER THE GREAT LAKES WILL DOMINATE THE WX
PATTERN THROUGH THE LONG TERM...AS SEVERAL PIECES OF ENERGY ROTATE
AROUND IT AND CROSS NEAR OUR AREA. THIS WILL BRING UNSETTLED AND
COOLER WX THROUGH THE WEEK. MOST GUIDANCE SUGGESTS BEST CHANCE FOR
PRECIP ASSOCIATED WITH A FRONTAL PASSAGE LATE WED. SYSTEM WILL BE
MOISTURE STARVED WITH LITTLE CONNECTION TO GOM/ATL MOISTURE...SO
EXPECTING ONLY LIGHT PRECIP. AT THIS TIME...HIGHEST CHANCES ARE IN
NORTHERN HALF OF THE CWA.

CAA CONTINUES THROUGH MOST OF THE WEEK...WITH WESTERLY WINDS
PREVALENT. DESPITE THE DOWNSLOPE COMPONENT...TEMPS WILL BE
NOTICEABLY COOLER BY WEEKS END WITH MAX TEMPS LOW 60S/UPPER 50S AND
MIN TEMPS LOW 40S/UPPER 30S. COULD EVEN BE SOME FROST BY FRI MORNING
ALONG/NEAR MASON DIXON LINE WHERE GROWING SEASON HAS ALREADY BEGUN.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
VFR INTO SUNDAY AFTERNOON CWA WIDE. FLOW BECOMES ELY SUNDAY AS
THE HIGH CENTER DRIFTS OFF NEW ENGLAND.

STRONG LOW LIFTS INTO THE MIDWEST LATE SUNDAY THROUGH MONDAY. WARM
FRONT AND DEEP MOISTURE PLUME LIFTS OVER THE AREA LATE SUNDAY
AFTERNOON THROUGH SUNDAY NIGHT. HEAVY RAIN/IFR CONDS ACROSS THE DC
METROS EVENING INTO LATE SUNDAY NIGHT.

MON... MRNG FLGT RESTRICTIONS SHUD PART DURING THE MIDDAY. LT DAY
SHRA LKLY...W/ A FEW EMBEDDED TSRA. BRIEF FLGT RESTRICTIONS
PROBABLE W/IN STORMS.

VFR CONDITIONS EXPECTED THROUGH MOST OF PERIOD...EXCEPT IN RAIN
SHOWERS WHERE LOCALLY SUB-VFR CONDITIONS ARE POSSIBLE.

&&

.MARINE...
SCA FROM MIDNIGHT FOR NRN MD WATERS...THEN ALL BUT THE UPPER
TIDAL POTOMAC FM 3 AM TO THE MID MORNING. ALL WATERS THEN THROUGH
SUNDAY NIGHT AS STRONG WIND FIELD WITH 20 TO 25 KT AS HIGH
PRESSURE SHIFTS OFF THE NEW ENGLAND COAST.

WARM FRONT WITH HEAVY RAIN AND GUSTY SHOWERS CROSSES THE WATERS
SUNDAY NIGHT. SMW OR GALE LIKELY.

RAIN TO START THE DAY MON. THEN ONCE IT DEPARTS...SLY FLOW WL
RESUME...INCRSG BY MID-LT AFTN. SHUD BE ENUF INFLOW FOR MARGINAL SCA
CALIBER GUSTS. IN ADDITION XPCT TSRA ALONG/AHD OF CDFNT. SOME OF
THESE MAY CONTAIN STRONG GUSTY WINDS AND LARGE HAIL. SMW/S LKLY.

SCA POSSIBLE TUES MORNING IN CAA REGIME ONCE BL MIXING COMMENCES.
WINDS SHOULD DIMINISH TUES AFTN AS PRESSURE GRADIENT RELAXES FROM
DEPARTING SFC LOW.

&&

.TIDES/COASTAL FLOODING...
NELY FLOW INCREASES TONIGHT...ELY THROUGH SUNDAY...THEN SELY SUNDAY
NIGHT. WATER LEVELS WILL INCREASE ACROSS THE BAY...PARTICULARLY
SUNDAY NIGHT. MINOR COASTAL FLOODING IS POSSIBLE BY THE HIGH TIDES
EARLY MONDAY.

&&

.EQUIPMENT...
AUDIO DEGRADATION AT THE NOAA WEATHER RADIO CHARLOTTESVILLE
TRANSMITTER IS EXPECTED TO CONTINUE THROUGH THIS WEEKEND.
TECHNICIANS ARE SCHEDULED TO PERFORM MAINTENANCE AT THE
TRANSMITTER SITE MONDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT MONDAY FOR ANZ530>532-
     538>540.
     SMALL CRAFT ADVISORY FROM 3 AM SUNDAY TO 6 AM EDT MONDAY FOR
     ANZ533-534-536-537-541>543.
     SMALL CRAFT ADVISORY FROM 8 AM SUNDAY TO 6 AM EDT MONDAY FOR
     ANZ535.

&&

$$
UPDATE...WOODY!
PRVS...BAJ/HTS/MSE


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