Area Forecast Discussion
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000
FXUS61 KPBZ 300601
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
201 AM EDT WED JUL 30 2014

.SYNOPSIS...
SHOWER CHANCES TODAY AS ANOTHER WEAK DISTURBANCE MOVES THROUGH THE
BROAD LOW PRESSURE SYSTEM. TEMPERATURES WILL BEGIN TO MODERATE
TOWARD NORMAL BY LATE WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
A FEW THUNDERSTORMS LINGER NORTH OF THE AREA AS OF ABOUT 06Z.
THESE DEVELOPED EARLIER ALONG THE NOSE OF A RELATIVELY WEAK H5
JET MAX. AS WE PROGRESS FURTHER INTO THE EARLY MORNING HOURS...THESE
THUNDERSTORMS SHOULD CONTINUE TO WANE WITH LACK OF SUFFICIENT
INSTABILITY AND WITH THE UPPER LEVEL JET DIMINISHING. THUS...HAVE
DECREASED POPS NORTH OF I80 OVER THE NEXT SEVERAL HOURS.

MOSTLY CLEAR SKIES PERSISTING AS MID-LEVEL CLOUDS MOVING IN FROM
THE NW ARE DISSIPATING AS THEY ENCROACH. LLVL DEWPOINT DEPRESSIONS
REMAIN SUFFICIENT ENOUGH TO CURTAIL ANY WIDESPREAD FOG
DEVELOPMENT...HOWEVER A FEW SHELTERED AREAS COULD SEE SOME PATCHY
FOG THIS MORNING.

CURRENT WATER VAPORY LOOP SHOWS AN UPPER LEVEL VORT DROPPING SOUTH
THROUGH THE WRN GREAT LAKES. THIS QUICK MOVING DISTURBANCE WILL
GENERATE SCATTERED SHOWERS TODAY AS IT PIVOTS AROUND THE EXPANSIVE
LOW PRESSURE SYSTEM STILL RESIDING NEAR JAMES BAY. STEEPENING
LLVL LAPSE RATES AND DEEPER MOISTURE AVAILABILITY WILL HELP FUEL
CONVECTIVE SHOWER DEVELOPMENT. HOWEVER...INSTABILITY OVERALL IS
STILL LACKING WITH VERY LITTLE CAPE IN THE CHARGE SEPARATION
LAYER. WILL KEEP THE MENTION OF THUNDER OUT OF THE FORECAST FOR
THIS AFTERNOON.

SHOWER CHANCES DISSIPATE QUICKLY THIS EVENING AS THE WAVE PULLS
AWAY TOWARDS SUNDOWN. SEVERAL HI-RES MODELS INDICATING A SECONDARY
WAVE OF PRECIPITATION OVERNIGHT INTO THURS MORNING ASSOCIATED WITH
ANOTHER UPPER LEVEL TROF AXIS SWINGING THROUGH. THIS FEATURE IS
CORROBORATED AMONG THE MORE BROAD SOLNS OF THE 00Z NAM AND GFS.
THE DEEPER MOISTURE WILL REMAIN CLOSE TO THE UPPER LOW ACROSS OUR
NORTH...THIS WILL BE THE AREA THAT IS THE FOCUS OF SLGT AND CHC
POPS THROUGH ABOUT 12Z.
TAX

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...
SHORTWAVE EXITS WEDNESDAY NIGHT WITH SHOWERS ENDING. UPPER LEVEL
TROUGH THEN BEGIN TO LIFT OUT AS CLOSED LOW BEGINS TO SHIFT WEST
WITH HEIGHTS RISING OFF THE EAST COAST. TEMPERATURES WILL
GRADUALLY WARM THROUGH THE PERIOD AND APPROACH SEASONAL AVERAGES
FRIDAY. SHOWERS CHANCES WILL LINGER MAINLY TOWARD I-80 THURSDAY
AFTERNOON CLOSER TO LAKE MOISTURE AND COLDER TEMPERATURES ALOFT.
ON FRIDAY FLOW ALOFT WILL BEGIN TO SHIFT TO THE SOUTHWEST ALLOWING
DEEPER MOISTURE TO ADVECT NORTH. MODELS DIFFER ON HOW FAST AND
WHERE THIS WILL OCCUR...BUT WOULD EXPECT BETTER MOISTURE TO BEGIN
TO MOVE UP ALONG THE RIDGES BEFORE INCREASING FARTHER WEST TOWARD
OHIO. FOR NOW CHANCE POPS MOST LOCATIONS FRIDAY.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ALTHOUGH THE MEAN TROUGH MAINTAINS THROUGH THE WEEKEND...H500
HEIGHTS WILL HAVE RECOVERED TO THE POINT THAT ALLOWS SEASONABLE
TEMPERATURES. DEW POINT WILL REMAIN COMFORTABLE WITHOUT ANY
SIGNIFICANT MOISTURE INFLUX FROM THE SOUTH. A SHORTWAVE MAY PROVIDE
DECENT SHRA/TSRA COVERAGE SATURDAY AFTERNOON/EVENING...WHILE
SUNDAY WILL SEE A RETURN OF MORE SPARSE PRECIPITATION BEHIND THIS
DISTURBANCE. THERE ARE HINTS THAT THE TROUGH MAY TRY TO LIFT OUT
EARLY NEXT WEEK...AT LEAST TEMPORARILY. THIS MAY LEAD TO LITTLE OR
NO AFTERNOON PRECIP BY TUESDAY...AS WELL AS CONTINUED SEASONABLE
WARMTH.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS PREVAIL UNDER MAINLY CLEAR SKIES. HOWEVER...ANOTHER
AREA OF CLOUDS WILL SWING THROUGH FROM THE NORTHWEST WITH THE NEXT
UPPER LEVEL WAVE. WILL KEEP IN A VFR FORECAST FOR MOST PORTS ON
WEDNESDAY. THE EXCEPTION WILL BE AT FKL AND DUJ WHERE MVFR CIGS
WITH SHOWERS ARE POSSIBLE WITH THE PASSAGE OF A WEAK SURFACE
BOUNDARY WEDNESDAY AFTERNOON.

OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
NO WDSPRD RSTRNS EXPD.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$






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