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155
FXUS61 KLWX 230128
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
928 PM EDT FRI AUG 22 2014

.SYNOPSIS...
DEEP HIGH PRESSURE WILL REMAIN CENTERED OVER THE DEEP SOUTH
THROUGH THE WEEKEND. MEANWHILE...SURFACE HIGH PRESSURE WILL BUILD
SOUTHWEST FROM NEW ENGLAND...WITH AN ONSHORE FLOW ACROSS THE
AREA. HIGH PRESSURE WILL CENTER OVER THE MID- ATLANTIC THROUGH THE
MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 01Z...LONGWAVE RIDGE IS ACROSS THE CNTRL CONUS WITH THE AXIS
JUST WEST OF THE MS RIVER. 1023MB SFC HIGH PRESSURE IS OVER
LABRADOR WITH A SFC RIDGE EXTENDING SOUTHWEST TO THE MID-ATLANTIC.
THIS IS RESULTING IN A BACKDOOR COLD FRONT AND ONSHORE FLOW EAST
OF THE BLUE RIDGE. THIS SFC HIGH WILL CONTINUE TO BUILD SOUTHWEST
THROUGH THE WEEKEND (AND THE ONSHORE FLOW WILL CONTINUE THROUGH AT
LEAST MONDAY). LOW CLOUDS SPREAD WEST ACROSS THE AREA OVERNIGHT.

WITH STABLE ONSHORE FLOW...THE ONLY CAPE REMAINING IS WEST OF THE
BLUE RIDGE AND DIMINISHING. SHOWERS AND ISOLATED THUNDERSTORMS
WILL PERSIST OVER THE CENTRAL SHENANDOAH VALLEY AND VICINITY
THROUGH THE LATE EVENING.

MIN TEMPS MID 60S INLAND (THE ONSHORE FLOW IS ACTUALLY DRIER THAN
THE CURRENT AIR)...AROUND 70F FOR NEARSHORE URBAN AREAS.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
THE AIR MASS OVER THE MID ATLC WL RMN MOIST SAT...HENCE SKIES WL
AGN HV PLENTY OF CLDS W/ CHCS FOR RW IN THE MRNG THRU MIDDAY. HIGH
PRES OFF THE NEW ENGLAND CST WL BEGIN BLDG INTO THE MID ATLC DURG
THE AFTN. THIS COULD TRIGGER SOME LTNG BUT NOT XPCTG A SVR THREAT.
SKIES COULD BEGIN CLRG IN NERN MD BY LATE AFTN.

LATE AUG HIGH TEMPS SHOULD BE IN THE M80S. XPCT TEMPS TO BE A FEW
DEGS BLO THAT.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
SOUTHWARD MOVING UPPER SHORTWAVE TROUGH WILL PUSH REINFORCING
BACKDOOR COLD FRONT ACROSS THE MID-ATLANTIC SATURDAY NIGHT INTO
SUNDAY. RESIDUAL MOISTURE BEFORE THE FROPA ALONG WITH UPSLOPE FLOW
AND UPPER TROUGH ENERGY SHOULD CONTINUE TO PRODUCE SHOWERS ACROSS
MAINLY THE BLUE RIDGE AND POTOMAC HIGHLAND SUNDAY NIGHT.
DRIER/COOLER AIR PUSHES IN BEHIND THE FRONT WITH HIGH PRESSURE FOR
SUNDAY.

POSITIVELY TILTED UPPER RIDGE AND SURFACE HIGH PRESSURE WILL
THEN DOMINATE THROUGH MID NEXT WEEK WITH SLOWLY MODERATING
TEMPERATURES AND HUMIDITY. POSITION OF UPPER FLOW LOOKS TO KEEP ANY
TROPICAL SYSTEM ACTIVITY OFFSHORE THE MID-ATLANTIC NEXT WEEK AS
WELL.

RETURN FLOW SETS IN WITH TEMPS BACK TO NORMAL FOR THURSDAY
AHEAD OF A PROGRESSIVE UPPER TROUGH MOVING ACROSS THE NORTHERN
CONUS. THIS DEEPENING TROUGH DRAGS A SEASONABLY STRONG COLD FRONT
THROUGH THE REGION FOR THE END OF THE WORK WEEK...WITH FRIDAY
LOOKING TO BE BACK IN THE UPPER 70S/LOW 80S ATTM. DEEP-LAYER WIND
SHEAR AND INSTABILITY MAY BE FAVORABLE FOR SOME ORGANIZED CONVECTION
WITH THIS COLD FROPA.

&&

.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
OVC AND MVFR/IFR CIGS XPCTD TO SPREAD WEST ACROSS THE TERMINALS
OVERNIGHT. MVFR CIGS HOLD ON MUCH OF SATURDAY WITH SOME RAIN
CHANCES THROUGH THE AFTERNOON. SKIES CLEAR FROM INCREASING HIGH
PRESSURE SUNDAY.

HIGH PRESSURE/VFR WILL PREVAIL THROUGH MIDWEEK BEFORE A COLD
FRONT PUSHES THROUGH FRIDAY.

&&

.MARINE...
BACKDOOR COLD FRONT HAS BROUGHT ONSHORE FLOW...CHANCE OF SCA
LOW...BUT WINDS WILL BE AROUND 15 KT THROUGH THE WEEKEND. WOULD
NOT BE A SURPRISE TO SEE STRONGER GUSTS AT TIMES...REQUIRED
STATEMENTS AND ADVISORIES.

COLD FRONT MAY BRING SOME SHOWERS TO THE BAY SATURDAY NIGHT.
WINDS LOOK TO STAY BELOW SCA LEVELS. HIGH PRESSURE WILL THEN BUILD
ACROSS THE AREA SUNDAY THROUGH MID WEEK BEFORE ANOTHER COLD FRONT
PUSHES THROUGH FRIDAY.

&&

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

&&

$$
UPDATE...JACKSON
PREVIOUS...WOODY!/AEB






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