419
FXUS61 KPBZ 161155
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
755 AM EDT THU JUL 16 2026
WHAT HAS CHANGED
UPDATED AVIATION DISCUSSION.
KEY MESSAGES
1) ABOVE AVERAGE TEMPERATURES AND SMOKE PERSIST LATE-WEEK.
2) STORM CHANCES, ALONG WITH SEVERE AND FLOODING RISKS, RETURN
INTO THE WEEKEND.
DISCUSSION
KEY MESSAGE 1...
THURSDAY, THERE IS HIGH CONFIDENCE THAT NEAR-SURFACE SMOKE
CONCENTRATIONS WILL INCREASE FROM WILDFIRES ORIGINATING IN
SOUTHERN ONTARIO AND NORTHERN MINNESOTA. EXACT CONCENTRATIONS OF
SMOKE WILL DEPEND ON THE EXACT INTENSITY OF UPSTREAM FIRES, BUT
CURRENT THOUGHTS SHOW MODERATE AIR QUALITY DEGRADATIONS, THOUGH
NOT AS SEVERE AS THE SMOKE EVENT FROM JUNE 2023. SMOKE WILL
PROGRESS IN FROM THE NORTH, WITH CONCENTRATIONS RISING FOR THE
I-80 CORRIDOR AT SUNRISE; SOUTHWEST PA, EAST OH, AND THE
NORTHERN WV PANHANDLE MID-MORNING; AND NORTHERN WEST VIRGINIA IN
THE EARLY AFTERNOON. IN COORDINATION WITH OH, PA, AND WV
DEPARTMENTS OF ENVIRONMENTAL PROTECTION, AIR QUALITY ALERTS ARE
IN PLACE FOR THURSDAY. REFER TO YOUR STATE'S DEPARTMENT FOR
MORE INFORMATION. THE SMOKE IMPACTS ARE EXPECTED TO MAKE IT DOWN
TO THE WV COUNTIES AS WELL BUT PERHAPS NOT AS DENSE AS FURTHER
NORTH.
SMOKE MAY ACTUALLY KNOCK 2-3 DEGREES OFF FORECAST HIGH
TEMPERATURES, SLIGHTLY REDUCING HEAT RISK FROM THE DAY PRIOR.
TEMPERATURES ARE EXPECTED TO FALL BACK TO NEAR-NORMAL FOR THE
WEEKEND. NEAR SURFACE SMOKE IS EXPECTED TO LINGER UNTIL MORE
FLOW OR RAIN CLEARS IT OUT. AT THIS POINT, MODELING HAS IT
THROUGH AT LEAST FRIDAY, BUT BOUTS MAY LAST THROUGH THE WEEKEND.
IN ADDITION TO THE SMOKE IMPACTS, WITH THE MORE HIGHER
CONCENTRATIONS OF SMOKE TO THE NORTH, THERE STANDS TO BE A
POTENTIAL OF DIFFERENTIAL HEATING ALONG I-70 AND SOUTH. THIS
WILL CREATE A GRADIENT, WITH THE POTENTIAL OF SHOWERS AND
THUNDERSTORMS DEVELOPING IN THE 18Z TO 00Z TIMEFRAME. THIS
ENOUGH TO PROMPT A MARGINAL RISK OF SEVERE WEATHER.
KEY MESSAGE 2...
THE RIDGE BREAKDOWN WILL OCCUR DURING THE FRIDAY AND INTO
SATURDAY PERIOD. THIS WILL TEND TOWARDS A PATTERN OF WESTERN
RIDGING AND EASTERN TROUGHING, ALONG WITH COOLING TEMPERATURES
INTO SATURDAY, SUNDAY, AND EARLY NEXT WEEK.
ENSEMBLE CLUSTERING IS IN GOOD AGREEMENT IN THE GENERAL FLOW
THROUGH THE WEEKEND. THE MAIN UNCERTAINTY WILL BE 1) THE
PRESENCE OF A SHORTWAVE TROUGH LATE FRIDAY AND 2) THE TIMING AND
POSITION OF A SHORTWAVE TROUGH SATURDAY.
THE PERIOD ON FRIDAY WILL FEATURE THE SHORTWAVE TROUGH ARRIVING
INTO THE REGION WITH NORTHWEST FLOW ALOFT. HOWEVER, THE TIMING
NOW SEEMS TO BE LATE FRIDAY INTO FRIDAY NIGHT. SB INSTABILITY
DURING FRIDAY EVENING AT AROUND 400 J/KG AND THE 90TH
PERCENTILE INCREASING THAT TO 800 J/KG MAY ALLOW A FEW STORMS
TO SPAWN WITHIN THE AFTERNOON EVENING PERIOD. THE AMOUNT OF
INSTABILITY AND THE FLOW ALOFT MIGHT ALLOW FOR A STRONG TO
SEVERE STORM ON FRIDAY EVENING DESPITE THE GENERAL THUNDER
OUTLOOK.
THE SECOND ROUND COMES ON SATURDAY AS THE UPPER LEVEL TROUGH
DIGS SOUTHWEST INTO THE UPPER OH VALLEY WITH CONTINUED NORTHWEST
FLOW. HERE, ADDITIONAL MOISTURE INJECT INTO THE REGION WITH
SURFACE FLOW OUT OF THE SOUTHWEST. THE ENSEMBLES ARE GIVING SB
CAPE VALUES SATURDAY AFTERNOON AT AROUND 1800 TO 2000 J/KG. THE
90TH PERCENTILE IS NOT OUT OF THE QUESTION WITH NEAR 3000 J/KG
POSSIBLE. THE CWASP VALUES LOOK TO BE AROUND 60% WITH THE 90TH
PERCENTILE AT 70%, SATURDAY CERTAINLY LOOKS LIKE THERE WILL BE A
POTENTIAL FOR SEVERE WEATHER. A SLIGHT RISK OF SEVERE WEATHER
HAS BEEN ADDED.
THE OTHER CONCERN DURING THIS PERIOD WILL BE THE RAINFALL
POTENTIAL. BOTH FRIDAY NIGHT AND SATURDAY THROUGH SUNDAY MORNING
HAVE MARGINAL RISKS FOR EXCESSIVE RAINFALL. THE NBM MEAN FOR
THE WEEKEND HINTS AT TOTAL PRECIP AT AROUND 1.60 INCHES BUT THE
90TH PERCENTILE SHOWS THE POTENTIAL OF 3 INCHES. WITH THE PWATS
LOOKING TO APPROACH 1.8 AGAIN, THE 3 INCH 36 HOUR TOTALS FOR
FRIDAY AND SATURDAY CERTAINLY SEEM POSSIBLE.
AVIATION /12Z THURSDAY THROUGH MONDAY/
SOME FOG HAS DEVELOPED AT A FEW SITES THIS MORNING
(FKL/DUJ/ZZV) AND SHOULD BURN OFF BY 14Z. THE MAIN CONCERN FOR
TODAY WILL BE THE INCREASING IMPACT OF CANADIAN WILDFIRE SMOKE.
CURRENTLY ALOFT ACROSS MUCH OF THE AREA, THE SMOKE IS EXPECTED
TO INCREASE IN CONCENTRATION NEAR THE SURFACE THROUGH THE DAY.
AT THIS TIME, MVFR/IFR VISIBILITIES ARE FORECAST TO DEVELOP AS A
RESULT, ESPECIALLY NORTH OF THE PA/WV BORDER. A DIFFERENTIAL
HEATING GRADIENT IS EXPECTED TO SET UP AT THE THRESHOLD OF THE
DENSER SMOKE, WHICH COULD LEAD TO THE DEVELOPMENT OF ISOLATED
SHOWERS AND THUNDERSTORMS DURING THE LATE AFTERNOON/EARLY
EVENING. ZZV AND MGW ARE MOST LIKELY TO SEE THESE, AND HAVE
INCLUDED PROB30 GROUPS AS A RESULT. LIGHT WIND OF LESS THAN 10
KNOTS WILL DO LITTLE TO IMPROVE THE SMOKE.
OUTLOOK...
HIGH PRESSURE MAINTAINS LIGHT WINDS AND FEW CLOUDS THROUGH
FRIDAY. RESTRICTIONS WILL LIKELY COME IN THE WAY OF SMOKE
REDUCTIONS TO VISIBILITY WHICH WILL CONTINUE THROUGH FRIDAY
BEFORE LESSENING THIS WEEKEND. THUNDERSTORM CHANCES RETURN LATE
FRIDAY INTO THE WEEKEND AS UPPER LEVEL SHORTWAVES TRAVERSE THE
REGION.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...AIR QUALITY ALERT UNTIL MIDNIGHT EDT TONIGHT FOR PAZ008-009-
013-015-016-031.
OH...AIR QUALITY ALERT UNTIL MIDNIGHT EDT TONIGHT FOR OHZ039>041-
048>050-057>059-068-069.
WV...AIR QUALITY ALERT UNTIL MIDNIGHT EDT TONIGHT FOR WVZ001>004.
DISCUSSION...MILCAREK/SHALLENBERGER
AVIATION...CL
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page