FXUS61 KLWX 310759
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
359 AM EDT SAT JUL 31 2010

.SYNOPSIS...
WEAK HIGH PRESSURE WILL BE STATIONARY ACROSS THE REGION TODAY AND 
TONIGHT.  AN UPPER DISTURBANCE WILL CROSS THE MID ATLANTIC SUNDAY 
THROUGH SUNDAY NIGHT.  THIS UPPER DISTURBANCE WILL BE FOLLOWED BY 
WEAK HIGH PRESSURE MONDAY THROUGH WEDNESDAY...WHEN A COLD FRONT WILL 
CROSS THE AREA.
&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 0730Z...WEAK LOW LEVEL AREA OF HIGH PRESSURE EXTENDS FROM 
UPSTATE NY TO THE CENTRAL APPALACHIANS. ZONAL FLOW FROM H7 AND 
ABOVE IS RIDING OVER THE RIDGE...PROVIDING MID AND HIGH CLOUDS...AND 
A FEW BANDS OF VERY ELEVATED LIGHT SHOWERS/SPRINKLES ACROSS WV. 
ADDED CHC POPS FOR LIGHT SHOWERS ACROSS PENDLETON CO AHEAD OF BAND 
ACROSS N-CNTRL WV WITH SPRINKLES ACROSS THE ALLEGHENY FRONT THROUGH 
10Z. WILL HAVE TO MONITOR RADAR TRENDS FOR MORE EWARD 
PROGRESSION/POTENTIAL OF SPRINKLES FOR AREAS SUCH AS THE SHENANDOAH 
VALLEY.

HIGH PRESSURE PUSHES OFF THE COAST THIS AFTERNOON...ALLOWING SLY
RETURN FLOW UP THE VALLEYS OF THE WEST LATE THIS MORNING...THEN
ACROSS THE REST OF THE CWA BY THE LATE EVENING. CLOUDS CONTINUE TO
BUILD IN FROM THE WEST AND THICKEN THROUGH THE DAY...WENT MOSTLY
CLOUDY. MAX TEMPS MITIGATED BY CLOUDS...MID TO UPPER 80S.

SCALED BACK POPS AND REMOVED THUNDER DUE TO LACK OF FCST INSTABILITY 
AND SFC MOISTURE /DEWPOINTS TO REMAIN IN THE LOW 60S THROUGH THE 
DAY/.

MOISTURE INFLUX IMPROVES AS HIGH PRESSURE ANCHORS OFF THE
COAST...POP ACTUALLY INCREASES AND SPREADS EAST THROUGH THE NIGHT.
WENT WITH SHOWERS FOR WX-TYPE...SOME THUNDER MAY SNEAK UP ALONG
THE ALLEGHENY FRONT LATE TONIGHT. QPF IS DIFFICULT WITH PRECIP
MODE A BLEND OF AREAS OF RAIN AND SHOWERS...WENT WITH ONE TENTH OF
A QUARTER OF AN INCH TONIGHT FOR THE BLUE RIDGE AND WEST...UP TO A
TENTH EAST OF THE BLUE RIDGE. MIN TEMPS LOW TO MID 60S
INLAND...UPPER 60S TO NEAR 70F NEAR SHORE.
&&

.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
SHORTWAVE TROUGH PASSES THROUGH NE US STATES ON SUNDAY.  GFS SHOWING 
FCST SFC CAPES IN OUR CWA FROM 500 J/KG IN THE PIEDMONT TO 1000 J/KG 
ACROSS THE HIGHER TERRAIN. SKY COVER FCST IS FOR CONSIDERABLE 
CLOUDINESS WHICH WILL LIMIT DESTABILIZATION...THUS DO NOT CONSIDER 
IT MUCH OF A SEVERE THREAT XCPT IN THE HIER TERRAIN.  HOWEVER I AM 
EXPECTING SCT-NUM SHRA AND TSTMS...WHICH WILL CONTINUE INTO THE LATE 
EVENING E OF INTERSTATE 95.
&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
VERY UNSETTLED WEATHER THROUGH WEDNESDAY AS RETURN FLOW AROUND HIGH 
PRESSURE PROVIDES PRECPITABLE WATERS IN THE 1.5-1.8 RANGE...ALONG 
WITH SEVERAL BOUTS OF ENERGY RIDING ALONG THE H5 JET. MOST LIKELY 
TIME FOR SHRA/TSTMS WILL BE DURING AFTERNOON PEAK HEATING IN THIS 
UNSETTLED PERIOD.

WEDNESDAY A MODERATE-STRONG COLD FRONT WILL APPROACH FROM THE WEST. 
WHAT IS NOTABLE ABOUT THIS FEATURE IS THAT THE PRECIPITABLE WATER 
WILL POOL AHEAD OF THE FRONT TO A MAGNITUDE APPROACHING 2.5 INCHES 
PER THE 00Z GFS...WHICH WOULD LIKELY KICK OFF HEAVY SHOWERS AND 
TSTMS WEDNESDAY INTO WEDNESDAY NIGHT BEFORE AND DURING FROPA. 
THURSDAY AND FRIDAY WILL BE DRYING OUT AS FRONT MOVES OFF COAST.
&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
VFR PREVAILS AS MID LEVEL CLOUDS THICKEN TODAY. WLY/SWLY FLOW AOB 10 
KT BECOMES SLY THROUGH THE AFTERNOON ACROSS THE TERMINALS AS HIGH 
PRESSURE PUSHES TO THE COAST. SHOWERS MOVE IN/DEVELOP ACROSS THE 
TERMINALS TONIGHT.

SUNDAY AND SUNDAY NIGHT WILL HAVE OCNL MVFR TO ISOLTD IFR CONDITIONS 
DUE TO CIGS AND VSBY RESTRICTIONS IN SHRA/TSTMS/BR.
&&

.MARINE...
LIGHT WLY FLOW AS WEAK HIGH PRESSURE BUILDS THROUGH MIDDAY...THEN 
FLOW BACKS TO SLY THROUGH THE AFTERNOON AS THE HIGH CROSSES. SOME 
SHOWERS LATE TONIGHT OVER THE WATERS.

LIGHT WINDS AND WAVES EARLY IN THE PERIOD XCPT NEAR TSTMS. NEXT 
POSSIBLE TIME FOR SCA WILL BE WED/WED NIGHT WITH THE FROPA.
&&

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

&&

$$
SYNOPSIS...LEE
NEAR TERM...BAJ
SHORT TERM...LEE
LONG TERM...LEE
AVIATION...BAJ/LEE
MARINE...BAJ/LEE