972
FXUS61 KPBZ 190616
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
216 AM EDT TUE MAY 19 2026
WHAT HAS CHANGED
THE FORECAST REMAINS LARGELY UNCHANGED, WITH CONTINUED
CONFIDENCE IN STORM ARRIVAL IN EASTERN OHIO AND NORTHWEST
PENNSYLVANIA AFTER 8 PM TONIGHT.
KEY MESSAGES
1) HIGHEST RISK FOR SEVERE STORMS/DAMAGING WIND GUSTS WILL BE IN
AREAS OF NORTHWEST PA/EASTERN OH, WITH DIMINISHING RISK NEAR
PITTSBURGH. CONDITIONAL SEVERE THREATS REMAIN ON WEDNESDAY
SOUTHEAST OF PITTSBURGH WITH A DEPARTING FRONT.
2) HEAT IMPACTS FOR SENSITIVE POPULATIONS CONTINUE EARLY THIS
WEEK, WITH TEMPERATURES UP TO THE UPPER-80S TO LOW-90S.
DISCUSSION
KEY MESSAGE 1...
AN OUTFLOW BOUNDARY FROM EARLIER CONVECTION TO OUR WEST IS
MOVING WEST-TO-EAST SOUTH OF PITTSBURGH THIS MORNING. IT WOULD
NOT BE A SURPRISE TO SEE AN ISOLATED SHOWER POP ALONG IT, BUT
WITH BUOYANCY LARGELY TAPPED OUT AND HRRR/RAP/HRW SOUNDINGS
SHOWING CAPPING AT AROUND 500MB, ANYTHING MORE THAN THAT IS NOT
EXPECTED.
THAT CAPPING IS MAINTAINED THROUGH THE MORNING AND INTO THE
AFTERNOON, EVEN AS THE HEAT-PROVIDING UPPER RIDGE BEGINS TO
BREAK DOWN IN RESPONSE TO AN UPPER MIDWEST/GREAT LAKES
SHORTWAVE, AND AS 1500-2000 J/KG OF MUCAPE DEVELOPS. THUS, ONLY
ISOLATED/WIDELY SCATTERED ACTIVITY IS FORECAST AT MOST THROUGH
SUNSET, WITH AREAS NORTH OF I-80 PERHAPS A BIT MORE LIKELY TO
SEE A SHOWER/STORM THROUGH THEN GIVEN THAT AREA'S PROXIMITY TO
THE SHORTWAVE AND PERHAPS THE DEVELOPMENT OF A LAKE BREEZE
BOUNDARY.
AS FAR AS THE MORE ORGANIZED CONVECTIVE THREAT TONIGHT, THE
MOST LIKELY SCENARIO PRESENTED BY CAMS REMAINS THE DEVELOPMENT
OF STRONG TO SEVERE THUNDERSTORMS IN WESTERN OHIO IN THE
22Z-00Z WINDOW AHEAD OF A COLD FRONT, PERHAPS ASSOCIATED WITH A
PREFRONTAL TROUGH. THESE STORMS SHOULD BE WEAKENING AS THEY
APPROACH NORTHWEST PA/EASTERN OH AFTER 01Z OR SO DUE TO DIURNAL
BUOYANCY LOSS AS WELL AS 20-25 KNOTS OF 0-6KM SHEAR FOSTERING
ONLY LOOSE ORGANIZATION/LIMITED COLD POOL CONSOLIDATION. STILL,
WITH UP TO 900 J/KG OF DCAPE AVAILABLE NORTH AND WEST OF
PITTSBURGH, STRONG TO SEVERE DOWNDRAFT WINDS REMAIN A DECENT
POSSIBILITY IN THE TALLER STORMS; THIS IS THE AREA HIGHLIGHTED
IN SPC'S DAY 1 SLIGHT (LEVEL 2 OF 5) RISK. HAIL IS A LESSER
CONCERN DUE TO THE LOWER SHEAR AND POOR MID-LEVEL LAPSE RATES
LESS THAN 6C/KM. ALSO, WITH AROUND 100 M2/S2 OF 0-1KM STORM-
RELATIVE HELICITY AVAILABLE NORTH OF I-80, A TORNADO CANNOT BE
TOTALLY RULED OUT IN THIS AREA AS LCLS LOWER, ALTHOUGH 0-3KM
CAPE MAY BE A BIT LOW. CONVECTIVE INTENSITY IS EXPECTED TO WANE
OVERNIGHT AS THE PARENT COLD FRONT MOVES IN, BUT SOME SHOWERS
AND STORMS WILL CONTINUE.
WEDNESDAY STILL PRESENTS A MORE LIMITED AND CONDITIONAL SEVERE
THREAT IN THE LAURELS AND IN THE WV RIDGES. THIS WILL DEPEND ON
FRONTAL TIMING AND THE AMOUNT OF RAIN/CLOUD COVER IN THE REGION
DURING THE MORNING INTO THE AFTERNOON. A SLOWER FRONT, WITH LESS
PRECIPITATION AND SOME CLOUD BREAKS OUT AHEAD, COULD ALLOW
SUFFICIENT DESTABILIZATION FOR AN ISOLATED DAMAGING WIND THREAT.
SCENARIOS WITH A FASTER FRONT AND MORE SOLID CLOUD COVER COULD
LARGELY CHOKE OFF THE THREAT FOR STRONG CONVECTION. THIS WILL
NEED TO BE MONITORED, AND THE SPC MARGINAL (LEVEL 1 OF 5) RISK
SOUTHEAST OF PITTSBURGH SHOWS THE POTENTIAL THREAT AREA WELL.
AFTER WEDNESDAY, SEVERE CHANCES TAPER OFF.
KEY MESSAGE 2...
WITH TEMPERATURES HOVERING MOSTLY IN THE UPPER 60S AND LOWER 70S
THIS MORNING, A FEW MAXIMUM LOW TEMPERATURE RECORDS MAY BE
CHALLENGED TODAY.
AS THE RIDGE BREAKDOWN ALLUDED TO ABOVE TAKES PLACE TODAY, 500MB
HEIGHTS SHOULD EXPERIENCE A SLIGHT DECREASE AS COMPARED TO
YESTERDAY. COUPLED WITH THE LIKELIHOOD OF A BIT MORE DAYTIME
CLOUD COVER WITH LINGERING MOISTURE, HIGH TEMPERATURES ARE
LIKELY TO REACH LEVELS A DEGREE OR TWO COOLER THAN YESTERDAY.
THIS WILL KEEP MOST LOCATIONS IN THE UPPER 80S, WITH LOWER-MID
80S NORTH OF I-80 AND IN THE TERRAIN. THE NBM CONTINUES TO SHOW
A WARM BIAS WITH ITS MEAN VALUES, AND KEPT THE FORECAST NUMBERS
LOWER AS A RESULT. THE NWS HEAT RISK REMAINS IN THE "MODERATE"
RANGE GIVEN THE CUMULATIVE EFFECT OF THE WARMTH SINCE YESTERDAY.
ANOTHER WARM AND MUGGY NIGHT IS POSSIBLE AHEAD OF THE COLD FRONT
AND THUNDERSTORMS TONIGHT, BUT THE PASSAGE OF THE COLD FRONT ON
WEDNESDAY WILL DEFINITIVELY END THE RISK OF EXCESSIVE HEAT FOR
THE FORESEEABLE FUTURE.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
VFR IS EXPECTED THROUGH MUCH OF THE DAY AS MID AND HIGH CLOUDS
CONTINUE TO INCREASE AHEAD OF AN APPROACHING COLD FRONT.
MODEL SOUNDINGS AND THE CU RULE INDICATE SCATTERED CUMULUS
CLOUDS SHOULD DEVELOP BY MID MORNING WITH SURFACE HEATING. THERE
IS A POTENTIAL FOR A SHOWER OR THUNDERSTORM TO AFFECT A FEW
AIRPORTS FROM LATE MORNING INTO EARLY AFTERNOON WITH LEFTOVER
BOUNDARIES FROM EARLIER CONVECTION TO OUR WEST, THOUGH THIS
POTENTIAL IS LIMITED, AND TOO LOW FOR TAF INCLUSION AT THIS
TIME. IN ADDITION, SW WIND IS EXPECTED TO GUST TO AROUND 20KT
DURING THE DAY WITH MIXING.
MORE SHOWERS AND THUNDERSTORMS ARE EXPECTED TO TRACK ACROSS OHIO
LATE THIS AFTERNOON AND EVENING IN ADVANCE OF AN APPROACHING
COLD FRONT. IT APPEARS THAT THE INSTABILITY SHOULD BE
DIMINISHING AS THESE STORMS ADVANCE EASTWARD, WITH AN OVERALL
WEAKENING TREND BY LATE EVENING. INCLUDED PROB30 MENTIONS FOR
MOST SITES ACROSS OHIO AND WESTERN PA, FROM MID TO LATE EVENING
AS THESE STORMS APPROACH.
OUTLOOK...
RESTRICTIONS AND SHOWERS ARE LIKELY BY LATE TUESDAY NIGHT INTO
WEDNESDAY AS THE COLD FRONT SLOWLY CROSSES THE UPPER OHIO VALLEY
REGION. A FEW THUNDERSTORMS ARE ALSO POSSIBLE. RESTRICTIONS ARE
POSSIBLE MAINLY SOUTH OF PIT WEDNESDAY NIGHT AND THURSDAY AS A
WAVE OF LOW PRESSURE TRACKS ALONG THE FRONT. RESTRICTIONS AND
SHOWERS RETURN FROM S-N FRIDAY INTO SATURDAY AS A WARM FRONT
LIFTS NORTH ACROSS THE AREA.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...CL
AVIATION...WM
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