914
FXUS61 KPBZ 150615
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
215 AM EDT FRI MAY 15 2026
WHAT HAS CHANGED
NO NOTABLE CHANGES WITH CONTINUED MESSAGE OF ABOVE-NORMAL
TEMPERATURES AND PERIODIC RAIN CHANCES.
KEY MESSAGES
1) TEMPERATURE RISES TOWARD WELL ABOVE-NORMAL READINGS BY EARLY
NEXT WEEK, WHICH COULD IMPACT HEAT SENSITIVE POPULATION
2) THUNDERSTORMS WITH NON-ZERO SEVERE THREAT EXISTS ON SATURDAY
AS WELL AS THE MIDDLE OF NEXT WEEK WITH UNRESOLVED DETAILS AT
THIS TIME.
DISCUSSION
KEY MESSAGE 1...
ENSEMBLE WEATHER MODELS REMAIN BULLISH ON HEIGHT RISES STARTING
TODAY CONTINUING INTO EARLY NEXT WEEK AS THE PREVIOUS GREAT
LAKES TROUGHING IS REPLACED BY EASTERN CONUS RIDGING. THE
RESULT IS TEMPERATURE APPROACHING SEASONAL AVERAGES TODAY,
ABOVE AVERAGE SATURDAY/SUNDAY, WELL ABOVE AVERAGE MONDAY/TUESDAY
WHERE AVERAGE IS APPROXIMATELY 72 DEGREES IN PITTSBURGH AT THIS
TIME OF YEAR. ONE POINT OF EVIDENCE IN THIS CONFIDENCE OF
SUMMER-LIKE HEAT IS THE MINIMAL SPREAD IN 850MB TEMPERATURES
THROUGH TUESDAY EVENING (NO MORE THAN 1 DEGREE BETWEEN 25TH-75TH
PERCENTILE OF GLOBAL ENSEMBLES). THOUGH IT IS HIGHLY UNLIKELY
HEAT ADVISORY CRITERIA (100 DEGREE OR MORE HEAT INDICES) IS
REACHED BASED ON OLD-SCHOOL RULES OF THUMB RELATED TO THOSE
850MB TEMPERATURES, LOCALIZED URBAN EFFECTS AS TEMPERATURES
REACH THE MID TO UPPER 80S THIS EARLY IN THE SEASON COULD CREATE
HEAT-RELATED IMPACTS TO SENSITIVE POPULATIONS.
KEY MESSAGE 2...
THE PREVIOUSLY MENTIONED PATTERN SHIFT WILL LIKELY ALSO CREATE
TWO MAIN PERIODS OF THUNDERSTORMS THAT OFFER NON-ZERO SEVERE
RISKS: SATURDAY AFTERNOON AND EVENING, AND SOMEWHERE IN THE
TUESDAY TO WEDNESDAY RANGE.
FOR SATURDAY, WEAK SHORTWAVE MOVEMENT WITHIN ZONAL FLOW ATOP THE
BUILDING SOUTHEAST CONUS RIDGE IS LIKELY TO GENERATE A
THUNDERSTORM COMPLEX NEAR THE IA/WI BORDER THAT TRAVELS TOWARD
THE UPPER OHIO RIVER VALLEY. LATEST GUIDANCE SUGGESTS LITTLE
WILL BE LEFT OF THIS INITIAL COMPLEX AS IT REACHES EASTERN OH
LATE SATURDAY MORNING, BUT IT COULD AIDE IN RE-DEVELOPMENT AMID
AN INCREASINGLY WARM, MOIST ENVIRONMENT WITH A NORTHWARD-LIFTING
WARM FRONT. THE MOST LIKELY SCENARIO UNDER THIS PREMISE FAVORS
SCATTERED TO LOCALLY NUMEROUS SUB-SEVERE SHOWERS/THUNDERSTORMS
FORMING NEAR THE I-77 CORRIDOR AND TRAVELING EAST THROUGH THE
EVENING AS WEAK SHEAR (20-25KTS) PLUS LOWER CAPE (LESS THAN 1000
J/KG) KEEP ACTIVITY MILD. BUT IF SURFACE HEATING IS MAXIMIZED
IN CONJUNCTION WITH LOW 60S DEWPOINTS, ENOUGH BUOYANCY COULD
LEND TO A LOWER-END HAIL AND DAMAGING WIND THREAT (WITH SLIGHT
HIGHER PROBABILITY FOR HAIL). CONFIDENCE IS LOW GIVEN
ENVIRONMENTAL STATE WILL BE HEAVILY INFLUENCED BY THAT DECAY
STORM COMPLEX, SO UNDERSTANDING OF THE THREATS (OR LACK THEREOF)
MAY NOT BE KNOWN UNTIL SATURDAY MORNING.
FOR TUESDAY/WEDNESDAY, SHORTWAVE MOVEMENT WITHIN SOUTHWEST FLOW
IS FAVORED BY ENSEMBLES THAT SHUNTS THE RIDGE SE AND CREATES
ENOUGH ASCENT WITH SURFACE LOW PASSAGE FOR WIDESPREAD SHOWERS
AND THUNDERSTORMS. TIMING AND DEPTH OF THE SHORTWAVE CREATES
VARIANCES IN WHEN THE AREA OF CONVECTION REACHES THE UPPER OHIO
RIVER VALLEY, RESULTING IN LARGE SPREADS IN ENVIRONMENTAL
PARAMETERS USED TO ASSESS SEVERE RISKS. THIS INCLUDES LARGE
RANGES FOR INSTABILITY, MID-LEVEL FORCING, AND UNCERTAINTIES IN
FEATURES LIKE MID-LEVEL WARM NOSES OR PRE-CONVECTION CLOUD
COVER LIMITING HEATING/DESTABILIZATION. THUS, IT IS BEST TO
REMAIN COGNIZANT OF THIS PERIOD LIKELY FEATURING
SHOWERS/THUNDERSTORMS AND MONITOR TRENDS INTO THE START OF NEXT
WEEK TO LEARN WHAT DEGREE SEVERE HAZARDS MAY BE IN PLAY OR NOT.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
NNW FLOW AROUND A SLOWLY DEPARTING UPPER LOW IS MAINTAINING A
STRATOCUMULUS DECK TO THE EAST OF PIT, WITH MOSTLY CLEAR SKY TO
THE WEST. MOST TERMINALS REMAIN VFR, SAVE FOR DUJ, WHICH WILL
MAINTAIN MVFR CEILINGS THROUGH MOST OF THE NIGHT.
CLOUDS WILL SLOWLY CLEAR OUT OVERNIGHT, LEAVING MOSTLY SUNNY
SKIES AT SUNRISE. THE REMAINDER OF THE TAF PERIOD WILL BE VFR,
AS THE PERIOD WILL BE DOMINATED BY MAINLY HIGH CLOUDS, WITH WARM
ADVECTION AND A WEAK SHORTWAVE THIS EVENING. LIGHT NORTHWEST
WIND THROUGH THE MORNING WILL BACK TOWARDS THE SOUTHWEST BY
TONIGHT.
OUTLOOK...
VFR CONTINUES INTO SATURDAY MORNING, BUT RESTRICTIONS AND RAIN
CHANCES RETURN SATURDAY AFTERNOON INTO SUNDAY WITH SOME SHOWER
AND THUNDERSTORM CHANCES, ESPECIALLY SATURDAY NIGHT. VFR RETURNS
EARLY NEXT WEEK.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...FRAZIER
AVIATION...CL
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