399
FXUS61 KPBZ 052346
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
746 PM EDT FRI JUN 5 2026
WHAT HAS CHANGED
UNCERTAINTY WITH SATURDAY MORNING PRECIP AND CLOUD COVER WHICH WILL
IMPACT THE SEVERE THREAT LATER IN THE DAY.
KEY MESSAGES
1) SHOWERS AND STORMS RETURN ON SATURDAY WITH A SEVERE THREAT
2) DRY AND WARM AGAIN EARLY NEXT WEEK WITH DAILY SHOWER/STORM
CHANCE FOR THE LATTER HALF
DISCUSSION
KEY MESSAGE 1...
THE PATTERN TURNS MORE ACTIVE ON SATURDAY AS A SHORTWAVE MOVES
THROUGH THE GREAT LAKES AND SHUNTS THE ECONUS RIDGE IN RESPONSE.
SOUTHWESTERLY FLOW WILL STRENGTHEN A BIT SATURDAY MORNING AND
PROMOTE SOME MOISTURE RETURN BUT WITH ENSEMBLE MEANS STILL ONLY
TOPPING DEW POINTS OUT IN THE UPPER 50S. THE SHORTWAVE PASSAGE IS
EXPECTED TO SPARK OFF SHOWERS AND STORMS IN THE AFTERNOON WITH STILL
LOW CONFIDENCE IN THEIR POTENTIAL SEVERITY. PRIMARY UNCERTAINTY
STEMS FROM THE EVOLUTION OF DECAYING OVERNIGHT CONVECTION THAT'LL BE
ONGOING OFF TO OUR WEST THIS EVENING. THESE SITUATIONS ARE
FREQUENTLY POORLY MODELED WITH THIS ONE HOLDING TRUE TO THAT,
AND THUS THE FORECAST, EVEN 24 HOURS OUT, REMAINS TOO LOW
CONFIDENCE TO DISCUSS SPECIFICS FROM HAZARDS TO TIMING. ANY
CERTAINTY WITH THE FORECAST WON'T ARISE UNTIL WE SEE HOW
CONVECTION TO OUR WEST EVOLVES TODAY AND TONIGHT. REMNANT
OUTFLOW, POTENTIAL MCV DEVELOPMENT, OVERALL COVERAGE, AND DEGREE
OF LOCALIZED MOISTURE INCREASE WILL ALL DICTATE HOW THE
AFTERNOON PLAYS OUT WITH THE GOAL POSTS RANGING FROM A LOWER END
HEAVY RAIN AND WIND THREAT TO AN ALL HAZARDS SEVERE THREAT.
REGARDLESS OF MORNING EVOLUTION, MOST CAMS DO FAVOR ATMOSPHERE
RECOVERY BY AFTERNOON WITH THE HREF PROB FOR >1000 J/KG SBCAPE
AND 30 KNOTS OF DEEP LAYER SHEAR AT 70+% SUPPORTING A FAVORABLE
ENVIRONMENT FOR SEVERE WEATHER. OF NOTE: AS IT'S EARLY JUNE, IT
DOES NOT TAKE MUCH SUN TO RAPIDLY INCREASE TEMPERATURES AND
DESTABILIZE THE ATMOSPHERE. SO EVEN IF MORNING SHOWERS/CLOUDS
LINGER, JUST A COUPLE HOURS OF CLEARING WOULD BE ENOUGH, THOUGH
A BALANCE WOULD BE NEEDED SO AS THERE'S ENOUGH TIME TO
DESTABILIZE BUT NOT TOO MUCH TO MIX OUT DEW POINTS. IN SHORT,
WE'RE STILL UNCERTAIN WITH NUMEROUS FACTORS AT PLAY. IN THE
MAJORITY OF OUTCOMES, INITIATION IS LIKELY FIRST TO THE NORTH
AND SINKING SOUTH THROUGH THE EVENING.
THE SLIGHT RISK FROM SPC REMAINS UNCHANGED, AND ML & AI GUIDANCE
HONES IN ON OUR AREA AS WELL FOR A HEIGHTENED SEVERE RISK. WPC HAS
ALSO PLACED US IN A MARGINAL RISK FOR EXCESSIVE RAINFALL PRIMARILY
IN THE CASE THAT URBAN AREAS SEE REPEATED ROUNDS OF HEAVY RAIN FROM
STORMS.
KEY MESSAGE 2...
RIDGING IS THEN PROGGED TO BUILD BACK IN EARLY NEXT WEEK AMONG ALL
ENSEMBLE GUIDANCE WITH SOME UNCERTAINTY IN TEMPERATURES FOR MONDAY
AND TUESDAY AS THE DEPARTING TROUGH TO THE EAST EXHIBITS SOME TIMING
DIFFERENCES AS DOES THE ORIENTATION AND STRENGTH OF THE BUILDING
RIDGE. LINGERING TROUGHING COULD HOLD TEMPERATURES IN THE UPPER 70S
WHILE QUICKER RIDGING COULD POINT TO 80S FOR THE MAJORITY OF THE
WEEK. EITHER WAY, A RETURN OF DRIER AND WARMER WEATHER IS
ANTICIPATED FOR AT LEAST THE FIRST HALF OF NEXT WEEK. RIDGING THEN
MAY BREAK DOWN SOME AND ALLOW FOR SOME SUMMERTIME-LIKE AFTERNOON
SHOWERS AND STORMS, THOUGH WITH SURFACE HIGH PRESSURE IN THE
VICINITY, COVERAGE SHOULDN'T BE WIDESPREAD OR BRING A NOTABLE SEVERE
WEATHER RISK. HIGH TEMPERATURES WILL BE HIGHLY DEPENDENT ON COVERAGE
OF CONVECTION.
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
MID-LEVEL CLOUDS ARE EXPECTED TO ADVANCE INTO THE REGION TONIGHT
FROM THE WEST DUE TO CONVECTION SOUTH AND WEST OF THE GREAT
LAKES.
AS EARLY AS TOMORROW MORNING, A DISTURBANCE TO OUR WEST COULD
POTENTIALLY IMPACT OUR REGION WITH SHOWERS AND ISOLATED STORMS.
THESE MAY FORM ON THE EDGE OF AN OUTFLOW BOUNDARY BETWEEN 11Z
TO 15Z SATURDAY, HOWEVER, GIVEN THAT CONVECTION WILL BE
DISORGANIZED, ONLY MENTIONED IN PROB30S FOR A FEW TERMINALS.
LIGHTNING AND VISIBILITY RESTRICTIONS WOULD MOST LIKELY BE THE
MAIN CONCERN.
A TROUGH IS EXPECTED TO CROSS THE REGION SATURDAY AFTERNOON AND
EVENING, SCATTERED THUNDERSTORM ARE EXPECTED TO REDEVELOP FROM
REMNANT OUTFLOW AROUND 18Z. EXACT TIMING OF IMPACTS TO AIRPORTS
IS UNCERTAIN, HOWEVER, THERE IS A SIGNAL FROM THE MODELS THAT
SHOW THIS COULD OCCUR IN TWO ROUNDS (ONE IN THE AFTERNOON AND
AGAIN IN THE EVENING). THE FIRST ROUND LOOKS TO BE MORE OF
LINEAR FORM WITH MODERATE CONFIDENCE IN TIMING AND LOCATION. SINCE
THE EVENING ROUND MAY BE MORE SCATTERED, TEMPOS HAVE BEEN ADDED
DUE TO LOWER CONFIDENCE IN TIMING AND LOCATION. A FEW STORMS
COULD BE STRONG TO SEVERE AND PRODUCE HAIL, WIND, AND ISOLATED
TORNADOES. THUNDERSTORM CHANCES WILL LIKELY DIMINISH WITH AN
ADVANCING COLD FRONT FROM THE NORTH BETWEEN 02Z TO 06Z SUNDAY.
OUTLOOK...
CIG RESTRICTIONS ARE POSSIBLE SUNDAY MORNING WITH LOW LEVEL
MOISTURE IN PLACE, BEFORE VFR RETURNS LATE IN THE DAY UNDER
BUILDING HIGH PRESSURE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
DISCUSSION...MLB
AVIATION...HEFFERAN/LUPO
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