Area Forecast Discussion
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FXUS61 KPBZ 030016 AAA
AFDPBZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
816 PM EDT TUE JUN 2 2015

.SYNOPSIS...
AN UPPER-LEVEL LOW WILL NEARLY STALL OVER THE OHIO AND TENNESSEE
VALLEYS THROUGH THURSDAY...WITH RAINFALL CHANCES MAINLY SOUTH AND
EAST OF PITTSBURGH. TEMPERATURES WILL RISE TO MORE SEASONABLE
LEVELS AS THE WEEK PROGRESSES.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
LOW CLOUDS HAVE BEGUN TO ERODE SOUTHWARD...BUT ARE EXPECTED TO
FILL BACK IN OVERNIGHT FOR AT LEAST THE SOUTHERN HALF OF THE
FORECAST AREA. CLOUD COVERAGE CONSEQUENTLY WAS DIMINISHED IN THE
NEAR TERM...BUT TRENDED BACK UPWARD DURING THE NIGHT.

WITH MOISTURE LINGERING TOMORROW...STRATOCU IS EXPECTED TO DEVELOP
ONCE DAYTIME HEATING ENSUES. LIMITED INSOLATION IS LIKELY TO
RESTRICT HEATING GIVEN CONTINUED EASTERLY WIND THROUGH MUCH OF
THE FIRST HALF OF THE DAY...SO MAXIMA WERE LOWERED A COUPLE OF
DEGREES.

POPS WERE ADJUSTED OVERNIGHT AND TOMORROW. UPPER LOW WILL REMAIN
PARKED FAR SOUTH OF THE FORECAST AREA...WITH LIGHT UPSLOPE FLOW
OFFERING THE BEST CHANCE OF GENERATING ANY PRECIPITATION. AS
SUCH...ANY LIGHT RAIN WILL BE TIED TO THE RIDGES AND POINTS JUST
DOWNSTREAM...SO POP GRADIENT WAS SHARPENED TO REFLECT THIS
EXPECTATION. PREV DISCUSSION FOLLOWS...

CLOUD SHIELD IS SLOWLY STARTING TO BREAK UP ACROSS FAR NORTHERN PA
AS NE WIND FUNNELS IN DRIER AIR. ITS STILL A TOUGH CALL HOW FAR
PARTIAL CLEARING GETS THIS AFTERNOON. LATEST HRRR HAS IT REACHING
THE I-80 VICINITY. THIS AGREES WELL WITH THE ONGOING FORECAST.
FARTHER SOUTH...SOUNDINGS ILLUSTRATE DEEPER MOISTURE AND DEWPOINTS
STAYING WITHIN A FEW DEGREES OF THEIR CURRENT READINGS...SO MOSTLY
CLOUDY/CLOUDY WORKS. WITH THE OVERCAST SKY...TEMPS WILL BE 15 TO
20 DEGREES BELOW NORMAL...HOWEVER MOST LOCATIONS SHOULD SEE AT
LEAST 60F. THE RECORD LOW HIGH FOR PITTSBURGH IS 51 AND WE ARE
ALREADY AT 57 WHICH MEANS ITS SAFE FOR ANOTHER YEAR.

AS FOR MEASURABLE PRECIPITATION...BAROCLINIC ZONE REMAINS DRAPED
ALONG THE SPINE OF APPALACHIANS...AND WEAK POCKETS OF DCVA RIDING
NORTHEAST COUPLED WITH A SATURATED COLUMN YIELD ISOLATED SHOWERS
FOR THE AFTERNOON OVER THE MOUNTAINS OF NRN WV AND WRN MD.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
NOT MUCH CHANGE TO THE FORECAST WEATHER PATTERN. CLOSED UPPER LOW
IS STILL EXPECTED TO CROSS THE TENNESSEE VALLEY AND SLOWLY TRUDGE
EASTWARD...BEFORE WEAKENING AND CROSSING THE CAROLINA COAST ON
FRIDAY. NAM/GFS TRY TO MOVE THE LOW CENTER A LITTLE QUICKER THAN
PREVIOUS RUNS...BUT THE ECMWF AND ENSEMBLES CONTINUE TO BE A
LITTLE SLOWER...WHICH IS PREFERABLE IN THIS STAGNANT PATTERN.

STILL EXPECT MOST RAIN SHOWER ACTIVITY WEDNESDAY/WEDNESDAY NIGHT
TO LIE SOUTH AND EAST OF PIT...ESPECIALLY CLOSE TO THE RIDGES...AS
EASTERLY FLOW KEEPS MOST MOISTURE LOCKED UP THERE. THIS IS ALSO
THE AREA THAT WILL BE MORE SUBJECT TO MIDLEVEL RIPPLES ROTATING
AROUND THE UPPER LOW. DID REDUCE POPS ON WEDNESDAY AND CONTINUED
TO KEEP THUNDER OUT OF THE FORECAST...AS THE TRANSITION TO A MORE
SOUTHERLY FLOW COMPONENT LOOKS DELAYED AS COMPARED TO YESTERDAY.

ON THURSDAY AND FRIDAY...BUFKIT PROFILES SHOW A MORE FAVORABLE
ENVIRONMENT FOR DIURNAL CONVECTION AREAWIDE AS RETURN FLOW SETS UP
ON BACK OF DEPARTING SURFACE HIGH TO OUR NORTH. GIVEN THE LACK OF
A COHERENT TRIGGER...WILL KEEP POPS IN THE SCATTERED/CHANCE
CATEGORY WEST OF THE RIDGES. WEAK UPSLOPING WILL CONTINUE IN THE
HIGHER ELEVATIONS...WITH A DAMMING LOOK TO THE LOW LEVEL WIND/TEMP
PROFILES.

FEWER CLOUDS AND THE RETURN OF SOUTHERLY FLOW WILL POINT TO A
WARMING TREND...WITH ABOVE NORMAL TEMPERATURES EXPECTED BY THE END
OF THE WEEK.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MODEL AND ENSEMBLE GUIDANCE CONTINUE TO FAVOR THE PASSAGE OF A
NORTHWESTERLY COLD FRONT ON SATURDAY...WHICH SHOULD FINALLY BRING
A DRIER PERIOD WITH AMPLE SUNSHINE BEHIND IT. HOWEVER...THE
IMPROVED CONDITIONS WILL LIKELY BE SHORT-LIVED AS THE CONSENSUS
FAVORS CYCLONIC FLOW RE-ESTABLISHING ITSELF OVER THE CWA BY EARLY
NEXT WEEK...MEANING A SOUTHERLY DROP OF THE JET AXIS AND A BETTER
CHANCE THE STORM TRACK WOULD FAVOR WET CONDITIONS AGAIN BY EARLY
NEXT WEEK.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
LOW CONFIDENCE FORECAST.

STRATUS HAS REMAINED ACROSS A MAJORITY OF THE FORECAST AREA
TODAY...WITH VFR CONDITIONS HAVING MOVED AS FAR SOUTH AS
BVI/BTP/DUJ. ALTHOUGH SYNOPTIC MODELS QUICKLY CLEAR OUT CLOUDS
TONIGHT AND BRING A RETURN TO VFR CONDITIONS...THINK THAT GFSLAMP
HAS A BETTER HANDLE ON STRATUS REMAINING ACROSS THE REGION DUE TO
THE STAGNANT AIRMASS AND EASTERLY WINDS THAT WILL PREVENT DRIER
AIR THAT WAS ADVANCING FROM THE NORTH. EXCEPT FOR FKL/DUJ...HAVE
GENERALLY GONE WITH MVFR/IFR CIGS OVERNIGHT. LOWER CEILINGS AND
VISIBILITIES ARE EXPECTED FARTHER TO THE SOUTH AND EAST. THAT
BEING SAID...WOULD NOT BE SURPRISED IF NAM/GFS WERE CORRECT AND
CLOUDS MANAGED TO CLEAR...OR IF GFSLAMP FORECAST TURNS OUT TO NOT
BE TOO PESSIMISTIC AND LIFR CIGS DEVELOP AFTER ALL.

AS WINDS PICK UP WEDNESDAY MORNING...CEILINGS SHOULD INCREASE FROM
THEIR OVERNIGHT HEIGHTS TO MVFR IN THE AFTERNOON AND VFR BY LATE
AFTERNOON. ANY CEILINGS IN THE AFTERNOON WOULD LIKELY BE FROM
DIURNAL CUMULUS...INSTEAD OF THE STRATUS DECK THAT HAS LINGERED
THE LAST TWO DAYS.

.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
CONDITIONAL RESTRICTIONS ARE EXPECTED INTO FRIDAY NIGHT AS UPPER
TROUGH REMAINS ENTRENCHED OVER THE EASTERN UNITED
STATES...BRINGING SCATTERED SHOWERS/THUNDERSTORMS.

&&

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

&&

$$

KRAMAR/TGREEN


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