-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 221920
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
320 PM EDT WED MAY 22 2013

.SYNOPSIS...
HIGH PRESSURE PERSISTING OVER THE ATLANTIC WITH WARM AND HUMID
CONDITIONS UNTIL A COLD FRONT THURSDAY NIGHT. AN UPPER TROUGH
WILL LINGER OVER THE AREA FRIDAY WITH HIGH PRESSURE BUILDING
THROUGH SATURDAY. A FRONTAL BOUNDARY STALLS OUT ACROSS THE MID-
ATLANTIC SUNDAY NIGHT THROUGH EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...

-- Changed Discussion --
HIPRES REMAINS IN THE WRN ATLC WHILE LOPRES RESIDES OVER THE
GRTLKS. SLY FLOW ACRS MID ATLC STATES CREATING A WARM UNSTBL AMS.
TSRA DVLPG ALONG THE WVA APLCHNS...WHERE DEWPTS HIER AND TEMPS
ALOFT A PINCH COOLER. OROGRAPHIC UPLIFT ALSO ASSISTING IN TSTM
DVLPMNT. THIS INITIATION IN LINE W/ WHAT MESOSCALE GDNC HAS
SUGGESTED. NOW THAT THE CAP HAS BEEN BROKEN...THERE/S PLENTY OF
INSTBY TO FEED OFF OF...BUT FEATURES FOR ORGANIZATION SLIGHTLY
LACKING. STILL DO NEED TO MONITOR THE UPR OHVLY WHERE HGTS LWR AS
THIS AREA RIPE FOR DVLPMNT. THAT POSES A SITUATION WHERE THESE
STORMS MAY PROPAGATE INTO AREA. AM KEEPING A LINEUP WHERE LKLY
POPS CONFINED TO THE MTNS AND CHC/SCHC ALONG I-95. THERE IS A
THREAT FOR LOCALLY DAMAGING WIND GUSTS AND LARGE HAIL IN ANY
THUNDERSTORMS THAT DO DEVELOP DUE TO THE HIGH INSTABILITY.

CONVECTION WILL LIKELY DISSIPATE LATER THIS EVENING DUE TO THE LOSS
OF DAYTIME HEATING. HOWEVER...AN UPPER-LEVEL DISTURBANCE IS EXPECTED
TO PASS THROUGH THE REGION LATE TONIGHT AS THE UPPER-LEVEL TROUGH
CONTINUES TO SLIDE CLOSER TO OUR AREA. PLENTY OF MOISTURE AND
FORCING FROM THE UPPER-LEVEL DISTURBANCE MAY RESULT IN SCATTERED
SHOWERS/T-STORMS TOWARD MORNING. RAISED APLCHNS TO LKLY. MIN TEMPS
TONIGHT WILL RANGE FROM THE 50S IN THE MOUNTAINS TO THE LOWER AND
MIDDLE 70S IN DOWNTOWN WASHINGTON/BALTIMORE.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
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HGTS CONT TO DROP THU AS CDFNT APPROACHES. ALTHO INSTBY WL BE
LWR...SHEAR WL BE GREATER. THERE MAY BE TWO ROUNDS OF WX...FIRST
COMING MIDDAY WITH THE DISTURBANCE AND RIBBON OF INSTBY...AND THEN
SECOND NEARER THE CDFNT AND DIURNAL HEATING. HV RAISED POPS INTO
THE DEF RANGE RATHER QUICKLY...AND HOLDING IT THERE THRUT THE DAY.

CFP THU NGT. WL SCALE BACK POPS AND TRANSITION FM TSRA TO SHRA IN
THE EVNG. AFTER FROPA...ONLY LINGERING SHRA WL REMAIN.

FRIDAY...UPR TROUGH DRIFTS EAST OVER THE AREA WITH BACK EDGE OF
CLOUDS SLOW TO COME IN THE AFTERNOON. GUSTY NWLY FLOW FRIDAY
CONTINUES AS HIGH PRESSURE BUILDS THROUGH SATURDAY.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
SHORTWAVE FROM TN VLY ON SUNDAY NOW LOOKS TO EXPAND EAST ACROSS THE
SOUTHERN-CENTRAL MID-ATLANTIC. CONVERGENCE ALONG THIS BOUNDARY WOULD
SET OFF SHOWERS. PATTERN IS STALLED INTO MID NEXT WEEK...SO A
PROLONGED CLOUDY/RAINY PERIOD IS POSSIBLE. THIS WOULD RESULT IN
BELOW NORMAL TEMPS.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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SHOWERS AND THUNDERSTORMS DVLPG...BUT STAYING W OF THE TERMINALS
ATTM. CONCERNED THAT THESE STORMS MAY DRIFT CLOSER...SPCLY FOR
CHO/MRB. HV VCTS IN ALL TAFS FOR THE EVNG DUE TO INSTBY PRESENT...
WHICH MAY LEAD TO ADDTL STORMS DVLPG. SOME OF THE THUNDERSTORMS
WILL BE CAPABLE OF PRODUCING GUSTY WINDS AND LARGE HAIL.

WL HV A RESPITE LT EVNG AS DIURNAL COMPONENT LOST. HWVR...ANOTHER
DISTURBANCE WL BE MOVING IN TWD MRNG...LEADING TO POTENTIALLY
ANTHR ROUND OF TSTMS. IFR CONDS POSSIBLE IN THE HEAVIEST ACTIVITY.
THREAT FOR STORMS CONT TIL CFP THURSDAY NIGHT. NWLY FLOW WITH
GUSTS 25 TO POSSIBLY 30 KT WITH MID LEVEL CIGS FRIDAY. NWLY FLOW
CONTINUES THROUGH SATURDAY AS HIGH PRESSURE BUILDS.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
HIGH PRESSURE WILL REMAIN OVER THE ATLANTIC OCEAN THROUGH TONIGHT. A
SOUTHERLY FLOW WILL CONTINUE OVER THE WATERS DURING THIS TIME. A
SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR PORTIONS OF THE WATERS
THROUGH TONIGHT. SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE
LATER THIS AFTERNOON AND EVENING. ANY THUNDERSTORMS THAT DO
DEVELOP WILL BE CAPABLE OF PRODUCING GUSTY WINDS AND HAIL.

SLY FLOW AHEAD OF A LATE THURSDAY NIGHT COLD FRONT. SCA EXPANDED
THROUGH THURSDAY. EXPECT AN EXTENSION THURSDAY NIGHT FOR PREFRONTAL
SLY FLOW...THEN NWLY FLOW AROUND 25 KT FRIDAY THROUGH SATURDAY AS
HIGH PRESSURE BUILDS.
-- End Changed Discussion --

&&

.TIDES/COASTAL FLOODING...
A SOUTHERLY FLOW WILL CONTINUE OVER THE WATERS THROUGH THURSDAY
NIGHT...BUT THE FLOW MAY REMAIN JUST WEST OF SOUTH. TIDAL ANOMALIES
WILL LIKELY INCREASE A LITTLE...BUT WITH THE FLOW REMAINING WEST OF
SOUTH THE WATER LEVELS SHOULD REMAIN BELOW THRESHOLDS FOR MINOR
COASTAL FLOODING. THE CLOSEST WATER LEVELS WILL COME TO MINOR
FLOODING THRESHOLDS WILL BE DURING THE HIGH TIDE CYCLE LATE WEDNESDAY
NIGHT AND LATE THURSDAY NIGHT...THE HIGHER OF THE TWO HIGH TIDES.
TIDAL ANOMALIES WILL DECREASE FRIDAY BEHIND A COLD FRONT.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 PM EDT
     THURSDAY FOR ANZ530-531-539.
     SMALL CRAFT ADVISORY FROM 9 AM TO 6 PM EDT THURSDAY FOR ANZ535-
     538.
     SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR ANZ532-536-
     540-542.
     SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR ANZ533-534-
     537-541-543.
-- End Changed Discussion --

&&

$$