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NWS Area Weather Forecast Discussion
County Warning Area [CWA]: PBZ
Regional NWS Weather Office: Pittsburgh, PA

000
FXUS61 KPBZ 011912
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
312 PM EDT SAT AUG 1 2015

.SYNOPSIS...
DRY WEATHER AND SEASONAL TEMPERATURES WILL CONTINUE THROUGH
SUNDAY BEFORE A COLD FRONT BRINGS A CHANCE OF SHOWERS ON MONDAY.

&&

.NEAR TERM /THROUGH SUNDAY/...
CUMULUS FIELD HAS SPREAD ACROSS THE ENTIRE REGION. ALTHOUGH THERE
IS LITTLE VERTICAL EXTENT WITH MOST OF THE CLOUDS...THERE ARE SOME
HIGHER CLOUD TOPS ALONG A CORRIDOR FROM MERCER TO INDIANA WITH
SOME RADAR RETURNS. DO NOT THINK THAT THERE WILL BE ANY RAINFALL
ACCUMULATION ALONG THIS CORRIDOR CONSIDERING THE TRANSIENT NATURE
OF THE SHOWERS AS WELL AS TWENTY DEGREE SURFACE DEWPOINT
DEPRESSIONS...BUT WILL MENTION SOME ISOLATED/SCATTERED SPRINKLES
INTO THE EVENING HOURS ACROSS THAT AREA. ALL LOCATIONS FROM
PITTSBURGH TO THE SOUTH ARE EXPECTED TO REMAIN FULLY DRY.

OVERNIGHT HIGH PRESSURE WILL SHIFT EAST INTO WEST
VIRGINIA...ALLOWING FOR ANOTHER CLEAR NIGHT WITH CALM/LIGHT WINDS.
HAVE GONE A FEW DEGREES COLDER THAN LAST NIGHT BECAUSE OF THE
BETTER CHANCE OF WINDS GOING CALM ALLOWING FOR FULL RADIATIONAL
COOLING. CLOUDS WILL BE ON THE INCREASE SUNDAY IN ADVANCE OF THE
NEXT COLD FRONT. CURRENTLY APPEARS THAT THE FRONT SHOULD STAY JUST
FAR ENOUGH TO THE WEST TO KEEP CONDITIONS DRY EVERYWHERE SUNDAY
AFTERNOON. THANKS TO SOUTHWESTERLY WINDS DEVELOPING...HIGHS SHOULD
INCREASE BY A COUPLE OF DEGREES INTO THE MID 80S.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
ALTHOUGH THE CHANCE FOR SHOWERS WILL INCREASE SUNDAY NIGHT...COLD
FRONT SHOULD MAKE ITS PASSAGE ACROSS THE REGION SOMETIME MONDAY
MORNING. DID NOT FEEL COMFORTABLE ENOUGH TO BUMP UP POPS TO LIKELY
OVER A WIDESPREAD AREA WITH MOISTURE AS A POSSIBLE LIMITING
FACTOR...ALTHOUGH DYNAMICS ALONG THE FRONT ARE FAVORABLE. FOR NOW
HAVE SIMPLY ADDED LIKELY POPS NORTH OF THE INTERSTATE 80 CORRIDOR.
SPC HAS A MARGINAL RISK FOR SEVERE WEATHER ON MONDAY. TWO CRITICAL
FACTORS WILL BE TIMING OF PRECIPITATION ALONG THE FRONT ALONG WITH
INSTABILITY VALUES (NAM HAS ABOUT 3 TIMES AS MUCH INSTABILITY AS
GFS...LIKELY DUE TO WET BIAS OF SURFACE DEWPOINTS).

ACCOMPANYING THE SURFACE COLD FRONT WILL BE AN UPPER LEVEL LOW
OVER SOUTHERN ONTARIO. WITH THE PROXIMITY OF THE LOW...SHORTWAVES
WILL BEGIN TO CRANK AROUND THE LOW. NAM/SREF BRING A SHORTWAVE ON
TUESDAY ACROSS THE REGION FROM THE NORTH...WHILE THE GFS/ECMWF
KEEP THE SHORTWAVE TO THE NORTH. BETWEEN THE SHORTWAVES AND THE
COLD FRONT EVENTUALLY STALLING OUT SOUTH OF THE AREA...HAVE GONE
WITH A BLANKET LOW CHANCE OF SHOWERS IN THE FORECAST. DIURNAL
SPREAD IN TEMPERATURES WILL SHRINK BY A FEW DEGREES DUE TO CLOUD
COVER THROUGH THE PERIOD.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
UPPER TROUGH WILL REMAIN SITUATED OVER THE EASTERN US THROUGH THE
LONG TERM WITH SEVERAL SHORTWAVES PROGGED TO HELP DEEPEN IT THROUGH
THE PERIOD. THIS WILL LIKELY KEEP TEMPERATURES JUST SLIGHTLY COOLER
THAN SEASONAL AVERAGES. BY LATE IN THE WEEK...MODEL GUIDANCE
SUGGESTS A SURFACE WAVE COULD DEVELOP AND LIFT ACROSS THE OHIO
VALLEY LATE. BUT...WITH RUN TO RUN INCONSISTENCY OPTED TO STAY
CLOSER TO WPC GUIDANCE VALUES...WHICH KEEP CHANCE POPS THROUGH THE
BEGINNING OF NEXT WEEKEND.

&&

.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
GENERAL VFR WILL CONTINUE INTO SUNDAY WITH DRY SURFACE HIGH
PRESSURE SUPPRESSING PRECIP UNDER NW FLOW ALOFT.

OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
RESTRICTION POTENTIAL WILL INCREASE WITH THE APPROACH AND PASSAGE
OF A MONDAY COLD FRONT.

&&

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

&&

$$

Forecast Discussion from: NOAA-NWS Script developed by: El Dorado Weather