380
FXUS61 KPBZ 200646
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
246 AM EDT MON JUL 20 2026
WHAT HAS CHANGED
NO MAJOR CHANGES HAVE BEEN MADE TO THE SEVERE WEATHER OUTLOOK
FOR TOMORROW, ENHANCED RISK REMAINS IN EFFECT ACROSS THE REGION.
KEY MESSAGES
1) CODE ORANGE AIR QUALITY ALERTS ISSUED FOR PARTS OF WESTERN PA
AND NORTHERN WV TODAY DUE TO LINGERING CANADIAN WILDFIRE SMOKE
2) ENHANCED RISK FOR SEVERE WEATHER ON TUESDAY; SLIGHT RISK FOR
EXCESSIVE RAINFALL
DISCUSSION
KEY MESSAGE 1...
LINGERING WILDFIRE SMOKE PARTICLES HAS PROMPTED A CODE ORANGE
AIR QUALITY ALERT (ISSUED BY THE PENNSYLVANIA DEPT. OF
ENVIRONMENTAL PROTECTION) ACROSS PORTIONS OF WESTERN
PENNSYLVANIA TODAY. SMOKE WILL LIKELY EXIT THE REGION, FROM
SOUTH TO NORTH, AS A NEW DISTURBANCE TRACKS INTO THE GREAT
LAKES AND SHIFTS THE UPPER-LEVEL WIND PROFILE.
KEY MESSAGE 2...
A STRONG LOW-PRESSURE SYSTEM WILL CONTINUE TO TRACK THROUGH THE
GREAT LAKES OVER THE NEXT 24 TO 48 HOURS, BRINGING AN INCREASED
RISK OF SEVERE WEATHER TO THE REGION ON TUESDAY. THE COMBINATION
OF ABUNDANT INSTABILITY (1500J/KG TO 2500J/KG OF CAPE) FUELED BY
WARM, HUMID AIR AND STRONG WIND SHEAR (35KT TO 45KTS OF
EFFECTIVE SHEAR) WILL CREATE A FAVORABLE ENVIRONMENT FOR
ORGANIZED SEVERE THUNDERSTORMS. AS A RESULT, THE STORM
PREDICTION CENTER CONTINUES TO HOLD THE ENHANCED RISK (LEVEL 3
OUT OF 5) FOR SEVERE WEATHER ACROSS OUR ENTIRE REGION. THE
LIKELIHOOD OF A SEVERE T-STORM OR A TORNADO WATCH DURING THE
AFTERNOON HOURS OF TUESDAY ARE CONSIDERED VERY HIGH.
RESIDENTS SHOULD PREPARE FOR DAMAGING WIND GUSTS, THOUGH
TORNADOES AND LARGE HAIL ARE ALSO POSSIBLE WITH ANY DISCRETE
SUPERCELL STORMS THAT ARE ABLE TO DEVELOP. SEVERE WEATHER
ANALOGS ASSOCIATED WITH SIMILAR SYNOPTIC PATTERNS IN THE SUMMER
SEASON STRONGLY SUPPORT DAMAGING WINDS OVER OUR REGION TO BE
THE PRIMARY THREAT.
SHOWERS AND ISOLATED NON-SEVERE STORMS MAY TRACK THROUGH THE
REGION EARLY TUESDAY MORNING IN THE WAKE OF THE OUTFLOW FROM A
PASSING MESOSCALE CONVECTIVE SYSTEM (MCS) TO OUR WEST. HOWEVER,
THE MAIN EVENT FOR STRONG TO SEVERE STORMS APPEARS FAVORABLE
BETWEEN 12PM AND 8PM TUESDAY.
ANOMALOUSLY HIGH MOISTURE LEVELS WITH PWATS REACHING THE 80TH
TO 90TH PERCENTILE RAISE THE RISK OF FLASH FLOODING TUESDAY
EVENING. TRAINING STORMS COULD POTENTIALLY CREATE LOCALIZED
SWATHS OF 3-4 INCHES OF RAINFALL IN A SHORT PERIOD OF TIME.
LOCATIONS THAT SAW SIGNIFICANT RAINFALL FROM THIS PAST WEEKEND'S
THUNDERSTORM ACTIVITY MAY BE ESPECIALLY VULNERABLE TO FLASH
FLOODING DUE TO ALREADY SATURATED SOILS AND INCREASED RUNOFF.
THE WEATHER PREDICTION CENTER (WPC) HAS ISSUED A SLIGHT RISK FOR
PORTIONS OF REGION. HIGH-RESOLUTION MODEL GUIDANCE CONTINUES TO
INCREASE THE PROBABILITY OF RAINFALL EXCEEDING FLASH FLOOD
GUIDANCE, WITH 30-50% PROBABILITIES WITHIN A 25 MILE RADIUS. AS
CONFIDENCE GROWS, A FLOOD WATCH WILL LIKELY BE ISSUED IN THE
NEXT 24 TO 36 HOURS. CURRENT MODEL GUIDANCE HIGHLIGHTS THE
GREATEST POTENTIAL FOR EXCESSIVE RAINFALL SOUTH OF PITTSBURGH,
WHERE ENHANCED LOW-LEVEL CONVERGENCE ACROSS EASTERN OHIO MAY
PROMOTE BACK-BUILDING THUNDERSTORMS.
EXPECT LINGERING SHOWERS AND NON-SEVERE THUNDERSTORMS INTO EARLY
WEDNESDAY BEFORE A COLD FRONT TRACKS THROUGH THE REGION AFTER
SUNRISE.
THE POTENTIAL FOR PRECIPITATION REMAIN LOWS THROUGH AT LEAST
SUNDAY UNDER HIGH PRESSURE.
AVIATION /06Z MONDAY THROUGH FRIDAY/
RIVER VALLEY FOG IS CURRENTLY DEVELOP ACROSS THE REGION, NOTED
ON NIGHTTIME MICROPHYSICS SATELLITE. AMENDMENTS MAY BE NEEDED
OVER THE NEXT 3 TO 6 HOURS FOR BRIEF PERIODS OF MVFR TO IFR FOG.
OTHERWISE, VFR CONDITIONS WILL PREVAIL WITH VARIABLE WINDS INTO
THE OVERNIGHT TIME PERIOD.
RESTRICTIONS WILL LIKELY RETURN TOMORROW WITH A PASSING LOW
PRESSURE SYSTEM. SHOWERS AND THUNDERSTORMS ARE EXPECTED PASS
OVER OR IN THE VICINITY OF ALL TERMINALS. CIG AND VIS
RESTRICTIONS WILL LIKELY OCCUR WITH THE CONDITIONS OF
-TSRA. DAMAGING WIND GUSTS, BETWEEN 40KT TO 60KTS COULD OCCUR
WITHIN A 25 MILES RADIUS OF ALL TERMINALS TUESDAY AFTERNOON
(BETWEEN 18Z TO 23Z).
OUTLOOK... REMNANT SHOWERS AND NON-SEVERE STORMS MAY TRACK
THROUGH THE REGION EARLY WEDNESDAY MORNING BEFORE A COLD TRACK
ADVANCES.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...AIR QUALITY ALERT UNTIL MIDNIGHT EDT TONIGHT FOR PAZ013-014-
020>022-029-031-073>078.
OH...NONE.
WV...NONE.
DISCUSSION...HEFFERAN
AVIATION...HEFFERAN
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