084
FXUS61 KPBZ 141720
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
120 PM EDT TUE JUL 14 2026
WHAT HAS CHANGED
WILDFIRE SMOKE ALOFT HAS BEEN OBSERVED ON SATELLITE, WITH
POTENTIAL TO DRIFT OVERHEAD IN THE BEGINNING OF THE PERIOD. A
HEAT ADVISORY HAS BEEN ISSUED FOR MOST OF THE AREA FROM NOON TO
8PM WEDNESDAY.
KEY MESSAGES
1) TEMPERATURES AND HEAT INDICES MAXIMIZE FOR MOST WEDNESDAY
WITH MAJOR HEAT RISK LIKELY.
2) WILDFIRE SMOKE ALOFT RETURNS TO THE AREA FOR THE BEGINNING OF
THE FORECAST PERIOD.
3) STORM CHANCES, ALONG WITH SEVERE AND FLOODING RISKS, RETURN
INTO THE WEEKEND.
DISCUSSION
KEY MESSAGE 1...
WILDFIRE SMOKE ALOFT MAY HAVE SLIGHTLY DECEASED TEMPERATURES
THIS AFTERNOON FROM THE PRIOR FORECAST, OTHERWISE, HEAT INDICES
INTO THE UPPER 90S CONTINUE TO BE LIKELY, WITH MOST OF THE
REGION IN MODERATE TO MAJOR HEAT RISK.
CURRENT GUIDANCE USING HRRR VERTICALLY INTEGRATED SMOKE HAS
TUESDAYS SMOKE DRIFTING SOUTH, LANDING IN MORE OF A MINIMA FOR
THE DAY ON WEDNESDAY, WHICH WILL BE MORE FAVORABLE FOR
TEMPERATURE CLIMBING CLOSE TO THE FORECAST. HREF PROBABILITIES
OF 90F OR GREATER ARE 90% TO 100% IN THE LOWLANDS SOUTH OF
US-422. UNCERTAINTY EXISTS NORTH OF THERE DEPENDING ON JUST HOW
FAST REINFORCING SMOKE MOVES IN. GIVEN THE TEMPERATURE AND DEW
POINT FORECAST, HEAT INDICES IN THE LOW 100S TO UPPER 90S ARE
FORECAST, WITH THE HOTTEST SPOTS IN URBANIZED AREAS AND/OR
VALLEYS. A HEAT ADVISORY WAS ISSUED FOR WEDNESDAY TO COVER THE
THREAT. MAJOR HEAT RISK IS FORECAST, PARTICULARLY WITH
CUMULATIVE EFFECTS FROM TUESDAY AND LOW TEMPERATURES IN THE
UPPER 60S TO LOW 70S FORECAST FOR MOST TUESDAY NIGHT AND
WEDNESDAY NIGHT.
THURSDAY, SMOKE CONCENTRATIONS MAY BE HIGHER, CHALLENGING
CONTINUED TEMPERATURES ABOVE 90F, SAVE REGIONS SOUTH OF US-22
WHERE MAJOR HEAT RISK MAY LINGER. THIS WILL ALSO CORRELATE TO
THE BEGINNING OF THE RIDGE BREAKDOWN.
KEY MESSAGE 2...
THE AFOREMENTIONED SMOKE THAT HRRR IS PICKING UP ON IS MOSTLY
FROM WILDFIRES ORIGINATING IN SOUTHERN ONTARIO AND NORTHERN
MINNESOTA. EXACT CONCENTRATIONS OF SMOKE WILL DEPEND ON THE
EXACT INTENSITY OF UPSTREAM FIRES. MODELS SHOW PROLIFIC SMOKE
RELEASE GIVEN THE CONTINUED HOT/DRY CONDITIONS.
AN INITIAL PUSH OF SMOKE TODAY IS EXPECTED TO REMAIN MOSTLY
ALOFT AND RESULT IN A MILKY/HAZY APPEARANCE OVERHEAD. THE MAIN
WAVE OF SMOKE TODAY IS FORECAST TO PASS TO THE SOUTH TOMORROW,
BEFORE WRAPPING BACK INTO THE MORE DENSE SMOKE ADVECTING DOWN
FROM ONTARIO WEDNESDAY NIGHT. THIS ROUND OF SMOKE MAY BRING
SOME MORE NEAR SURFACE SMOKE THAT COULD POSE IMPACTS TO NEAR
SURFACE AIR- QUALITY INTO LATE WEDNESDAY AND EARLY THURSDAY.
CONTINUED INSTANCES OF SMOKE APPEAR LIKELY INTO THE WEEKEND WITH
LITTLE CHANGE IN MID- LEVEL WIND DIRECTION.
KEY MESSAGE 3...
AS WITH MOST RIDGE BREAKDOWNS, THERE WILL ALSO COME A THREAT FOR
ORGANIZED STORM FORMATION. UNCERTAINTY WITH TIMING AND INTENSITY
IS STILL NOW TIED MOSTLY TO AN INFRINGING PACIFIC LOW REJOINING
THE FLOW AS A SHORTWAVE. ONCE THIS DOES SO (OVER THE NEXT 24
HOURS), IT'LL BECOME EASIER TO RESOLVE THE TIMING AND LOCATION
OF STORMS INTO FRIDAY AND SATURDAY. A FASTER REJOINING OF THIS
WOULD LEAD TO A FRIDAY ARRIVAL (LOWER PROBABILITY), AND A SLOWER
REJOINING WOULD LEAD TO A SATURDAY ARRIVAL (HIGHER
PROBABILITY). IF THE EASTERN TROUGH AMPLITUDE IS TOWARDS THE
HIGHER END, QPF TOTALS MAY BE TOWARDS THE HIGHER END OF THE
DISTRIBUTION AND DISPLACED INTO THE NORTHERN OHIO VALLEY,
WHEREBY, A LOWER TROUGH AMPLITUDE WOULD MEAN PERHAPS SLIGHTLY
LOWER QPF POTENTIAL AND DISPLACED INTO NORTHERN PENNSYLVANIA.
MACHINE LEARNING CARRIES GENERALLY A 5% TO 15% CHANCE OF SEVERE
WEATHER WITHIN 25 MILES OF A POINT WHEN AND WHERE THE THREAT
MAXIMIZES FOR NOW. WITH LREF 50TH PERCENTILE DCAPE NEAR 600 TO
900, A MARGINAL DOWNBURST THREAT IS POSSIBLE, BUT WITH MEAN
500MB FLOW OF 30KTS TO 50KTS, ORGANIZED CONVECTION IS CERTAINLY
POSSIBLE. CURVED LOW HODOGRAPHS WILL ALSO ALLUDE TO THE
POTENTIAL FOR DISCRETE OR EMBEDDED TORNADO THREATS.
ANOTHER THING THAT WILL NEED TO BE MONITORED, MAYBE EVEN MORE
SO, IS HYDROLOGICAL CONCERNS. LREF 50TH PERCENTILE PWATS WILL BE
>90TH PERCENTILE, AND CONVECTION MAY BE BOUNDARY PARALLEL AS IT
MOVES FROM THE NORTHWEST TO SOUTHEAST. MODEL SOUNDINGS SHOW
LONG, SKINNY CAPE. THERE ARE SOME PARTICULARLY HIGH-QPF ANALOGS
IN SIMILAR PATTERNS, AND NBM 90TH PERCENTILE TO MAX QPF SHOWS
2-5" IS CERTAINLY POSSIBLE SOMEWHERE.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
HIGH PRESSURE IN PLACE WILL MAKE FOR DRY CONDITIONS AND LIGHT
WINDS. WHILE A VFR FORECAST IS EXPECTED, IT IS POSSIBLE A FEW
AREAS OF FOG MAY DEVELOP TOMORROW MORNING. THERE IS LOW
CONFIDENCE OF IT OCCURING, SO IT WAS LEFT OUT OF THE TAFS.
DUE TO THE ELEVATED NORTHWEST FLOW ASSOCIATED WITH THE HIGH
PRESSURE SYSTEM, SMOKE FROM WILDFIRES IN NORTHERN MINNESOTA AND
WESTERN ONTARIO IS IN THE AREA. THIS IS ONLY CREATING A LIGHT
HAZE AND NOT REDUCING VISIBILITY. A DENSE AREA OF SMOKE IS
FORECAST TO MOVE SOUTH WEDNESDAY NIGHT INTO THURSDAY.
OUTLOOK...
HIGH PRESSURE FAVORS VFR THROUGH AT LEAST THURSDAY, WITH ONLY
LOW PROBABILITIES FOR RIVER VALLEY FOG NEAR DAWN. DUE TO A DENSE
AREA OF SMOKE FROM WILDFIRES IN NORTHERN MINNESOTA AND WESTERN
ONTARIO, IT IS POSSIBLE FOR MVFR VISIBILITY RESTRICTIONS ON
THURSDAY, HOWEVER, THERE IS LOW PROBABILITY AT THIS TIME.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...HEAT ADVISORY FROM NOON TO 8 PM EDT WEDNESDAY FOR PAZ007-008-
013>015-020>022-029-031-073-075-077.
OH...HEAT ADVISORY FROM NOON TO 8 PM EDT WEDNESDAY FOR OHZ039>041-
048>050-057>059-068-069.
WV...HEAT ADVISORY FROM NOON TO 8 PM EDT WEDNESDAY FOR WVZ001>004-
012-021-509.
DISCUSSION...MILCAREK
AVIATION...LUPO
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