997
FXUS61 KPBZ 262231
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
631 PM EDT FRI JUL 26 2024
SYNOPSIS
A WARMING TREND WITH DRY CONDITIONS THIS WEEKEND WILL BE
FOLLOWED BY SEASONABLY WARM AND UNSETTLED CONDITIONS NEXT WEEK.
NEAR TERM /UNTIL 6 AM SATURDAY MORNING/
KEY MESSAGES:
- PATCHY VALLEY FOG POSSIBLE TONIGHT.
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SMOKE ALOFT WILL GRADUALLY CLEAR TO THE SOUTH TONIGHT, GIVING
WAY TO CLEAR SKIES UNDER SUBSIDENCE AND HIGH PRESSURE. THE
PRESSURE GRADIENT WILL REMAIN WEAK WITH THE SURFACE HIGH
CENTERED OVER THE FINGER LAKES OF NEW YORK. THESE CALM AND CLEAR
SKIES WILL LEND TO EFFICIENT RADIATIONAL COOLING. THIS PROMPTED
NUDGING LOW TEMPERATURES TOWARD THE NBM 10TH PERCENTILE AND
KEEPING FOG CONFINED TO VALLEY LOCATIONS WITH RIVERS AND CREEKS
SERVING AS A WARM MOISTURE SOURCE. ANY FOG IS EXPECTED TO CLEAR
RAPIDLY BEYOND DAYBREAK. PROBABILITIES OF DENSE FOG REMAIN 0%
TO 10%.
SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/
KEY MESSAGES:
- REMAINING DRY BUT BECOMING WARMER.
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HIGH CONFIDENCE RIDGING BUILDS FOR MOST OF THE SHORT TERM PERIOD AS
AN UPPER LOW CUTS OFF TO OUR EAST AND TROUGHING DIGS TO OUR WEST
MAINTAINING DRY WEATHER LOCALLY. ENSEMBLE MEAN 500 MB HEIGHTS RISE
TO 588-591 DM AND, AS THE SURFACE HIGH SLOWLY MIGRATES EAST,
SOUTHERLY RETURN FLOW WILL BEGIN AN INCREASE IN TEMPERATURES AND
MOISTURE THROUGH THE WEEKEND. PROBABILITIES FOR >90F REMAIN AT
0% TO 20% FOR MONDAY AND JUMP TO 50 TO 60% ON SUNDAY PRIMARILY
IN RIVER VALLEYS AND URBAN AREAS SOUTH OF I-80. DEW POINTS ARE
FORECAST TO TICK FROM THE UPPER 50S AND LOWER 60S ON SATURDAY TO
THE LOW-TO-MID 60S ON SUNDAY. THIS SHOULD KEEP CONDITIONS
FEELING COMFORTABLE AND HEAT RISK LOW DESPITE ABOVE AVERAGE
TEMPERATURES.
RIDGING WILL BEGIN TO SHUNT TO THE EAST ON SUNDAY AS ENSEMBLE
CLUSTERS ABSORB A CUTOFF UPPER LOW BACK INTO THE FLOW ALOFT.
GENERALLY GOOD AGREEMENT AMONGST THEM ON ITS AMPLIFICATION AND
TRACK THROUGH THE OHIO VALLEY PROVIDES OVERALL HIGH CONFIDENCE
IN THE EVOLUTION OF THE PATTERN WHICH WILL INTRODUCE SOME HIGH
CLOUDS FROM THE WEST LATE ON SUNDAY.
LONG TERM /MONDAY THROUGH FRIDAY/
KEY MESSAGES:
- A FEW ROUNDS OF DISTURBANCES PASS INTO THE MIDDLE OF NEXT
WEEK.
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SOME DISAGREEMENT IN THE ENSEMBLE CLUSTERS COMES INTO PLAY WITH HOW
THE OTHER CUTOFF LOW TO OUR EAST EVOLVES, THOUGH MOST KEEP IT
AROUND TO A VARYING DEGREE THROUGH THE DAY ON MONDAY. THIS
SCENARIO WOULD FAVOR A SLIGHTLY DRIER SOLUTION, THOUGH IF IT
DEPARTS QUICKER WHICH IS CURRENTLY A LESS LIKELY BUT STILL
POSSIBLE OUTCOME, AN APPROACHING WAVE FROM THE WEST WILL BE
ALLOWED TO MOVE IN QUICKER AND SUPPORT A WETTER SOLUTION. EITHER
WAY, RAIN CHANCES INCREASE ON MONDAY AND CONTINUE THROUGH MID-
WEEK WITH A SERIES OF DISTURBANCES AS THERE IS GOOD AGREEMENT
THAT THE NORTHEAST SITS UNDER A LOW AMPLITUDE TROUGH UNDER-CUT
BY WARM MOIST SOUTHWEST FLOW IN RESPONSE TO A STRONG DEVELOPING
RIDGE OVER THE SOUTH-CENTRAL UNITED STATES. THIS PATTERN IS
CLIMATOLOGICALLY SUPPORTIVE OF SEVERE WEATHER CHANCES, ALTHOUGH
MANY OF THE DETAILS MAY NOT BE RESOLVED UNTIL NEXT WEEK DRAWS
CLOSER. MACHINE LEARNING CONTINUES TO PAINT A BROAD-BRUSHED, LOW
PROBABILITY SEVERE THREAT BY MID-WEEK.
WITH FLOW ALOFT EXTENDING DOWNSTREAM OF THE CANADIAN ROCKIES,
PROMINENT WILDFIRE SMOKE COULD MAKE ANOTHER RETURN TO THE PITTSBURGH
REGION, THOUGH FINE DETAILS ARE USUALLY RESOLVED WITH TWO DAYS LEAD
TIME.
AS OF THE MOST RECENT UPDATE, IT APPEARS THAT CLUSTERS ARE
BACKING OFF THE IDEA OF EXTREME HEAT IN THE NORTHEAST TO START
OFF AUGUST. ALL CLUSTERS NOW RETROGRADE THE RIDGE AXIS BACK
INTO THE WEST, MAINTAINING TROUGHING IN THE EAST. THIS SETUP IS
LESS SUSCEPTIBLE TO EXTREME HEAT, BUT CPC MAINTAINS THE MODERATE
RISK OF EXCESSIVE HEAT FOR NOW. WILL CONTINUE TO MONITOR FOR
CHANGES IN THE COMING DAYS.
AVIATION /22Z FRIDAY THROUGH WEDNESDAY/
VFR IS EXPECTED THROUGH THE TAF PERIOD AS HIGH PRESSURE BUILDS
ACROSS THE REGION. EARLY MORNING RIVER VALLEY STEAM FOG IS
EXPECTED, THOUGH THERE IS A LOW PROBABILITY THAT THE TAF SITES
WILL BE AFFECTED. THE CU RULE AND MODEL SOUNDINGS INDICATE
SCATTERED DIURNAL CUMULUS CLOUDS WILL DEVELOP AGAIN SATURDAY, AS
LIGHT NE WIND VEERS TO THE E.
OUTLOOK
VFR WILL CONTINUE THROUGH THE WEEKEND UNDER HIGH PRESSURE.
PERIODIC RESTRICTION POTENTIAL IN SHOWERS/THUNDERSTORMS RETURNS
MONDAY THROUGH WEDNESDAY WITH A SLOW MOVING TROUGH OF LOW
PRESSURE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...MILCAREK
NEAR TERM...MILCAREK
SHORT TERM...MLB/MILCAREK
LONG TERM...MLB/MILCAREK
AVIATION...WM
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