644
FXUS61 KPBZ 151104
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
704 AM EDT WED JUL 15 2026
WHAT HAS CHANGED
ADDED SMOKE TO THE GRIDS FOR LATE THIS AFTERNOON AND INTO
TONIGHT TO INCLUDE THURSDAY.
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...
THE RIDGE WILL BE IN PLACE OVER THE EASTERN CONUS TODAY, BUT
WILL BEGIN TO SHIFT BACK WEST. THIS WILL KEEP DRY CONDITIONS IN
PLACE. WITH NORTHWEST FLOW ALOFT BEGINNING TO TAKE SHAPE, THIS
WILL KEEP THE HIGHER DEW POINTS OUT OF THE REGION. THUS THE HEAT
RISK FOR TODAY WILL BE MARGINAL HEAT ADVISORY VALUES. VALUES OF
100 TO 102 ARE STILL EXPECTED BUT JUST CONFINED TO THE URBAN
AREAS OF THE FORECAST AREA. THE NORTHWEST FLOW WILL BEGIN TO
USHER IN SMOKE TO THE REGION BY THE AFTERNOON AND INTO THE
EVENING.
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...
THE RIDGE BREAKDOWN WILL OCCUR DURING THE FRIDAY AND INTO
SATURDAY PERIOD. WITH THE UPPER RIDGE SHIFTING WEST, THIS WILL
PUT THE NORTHEAST IN A TROUGHING PATTERN. WITH NORTHWEST FLOW
ALOFT AND SOME SURFACE MOISTURE ADVECTED INTO THE REGION, A
SEVERE AND FLOOD THREAT WILL BE IN PLACE. WPC AT THIS TIME HAS
PUT THE FRIDAY AND SATURDAY PERIOD
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. ENSEMBLES
CONTINUE TO HINT ON THIS POTENTIAL.
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 /12Z WEDNESDAY THROUGH SUNDAY/
VFR PERSISTS UNDER THE INFLUENCE OF UPPER LEVEL RIDGING WITH
SUBTLE REORIENTATION OF THE SURFACE PRESSURE FIELD TO YIELD A
WIND FIELD THAT VEERS FROM SW TO NW BY THE AFTERNOON WITH
OCCASIONAL GUSTS 15-20KTS.
WILDFIRE SMOKE LIKELY REMAINS LOFTED AT CIRRUS LEVELS THROUGH
THE MAJORITY OF THE TAF PERIOD BEFORE REACHING NEAR THE SURFACE
AT OR JUST AFTER THE TAF PERIOD, SPREADING SOUTH. ENOUGH
PARTICULATES MAY BE PRESENT TO AID LOCALIZED FOG FORMATION PRIOR
TO DAWN FOR LOCATIONS WITH BETTER NEAR-SURFACE MOISTURE OR
NEARBY RIVERS (ZZV/HLG/MGW).
OUTLOOK...
HIGH PRESSURE MAINTAINS VFR THROUGH THE MAJORITY OF THE MAJORITY
OF FRIDAY WITH LITTLE IN THE WAY OF CU DEVELOPMENT. HOWEVER,
WILDFIRE SMOKE FROM FAR NORTHERN MINNESOTA AND WESTERN ONTARIO
MAY FILTER TOWARDS THE SURFACE STARTING THURSDAY AND CAUSE
HAZE/SMOKE-RELATED VISIBILITY REDUCTIONS (PROBABLY NO LOWER THAN
MVFR) THAT COULD EXTEND INTO FRIDAY AND BEYOND, PENDING SMOKE
DENSITY.
THUNDERSTORM CHANCES RETURN LATE FRIDAY INTO THE WEEKEND AS
UPPER LEVEL SHORTWAVES TRAVERSE THE REGION.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
PAZ007-008-013>015-020>022-029-031-073-075-077.
OH...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
OHZ039>041-048>050-057>059-068-069.
WV...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
WVZ001>004-012-021-509.
DISCUSSION...MILCAREK/SHALLENBERGER
AVIATION...FRAZIER
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page