785
FXUS61 KCTP 100817
AFDCTP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
417 AM EDT WED JUN 10 2026
WHAT HAS CHANGED
* SEVERE WEATHER RISK LEVEL UPGRADED TO SLIGHT (2 OUT OF 5)
THURSDAY & FRIDAY
* HELD OFF ON HEAT ADVISORY ISSUANCE OWING TO LINGERING
UNCERTAINTY WITH PM STORMS THURSDAY & FRIDAY
KEY MESSAGES
1) INCREASING HEAT AND HUMIDITY WILL BRING INCREASED RISK FOR
HEAT-RELATED ILLNESSES THURSDAY, AND ESPECIALLY ON FRIDAY.
2) DAILY SHOWER AND THUNDERSTORM CHANCES CONTINUE THROUGH THE
END OF THE WORK WEEK WITH DAMAGING WINDS POSSIBLE.
3) A REFRESHING DECREASE IN HUMIDITY IS A GOOD BET THIS WEEKEND
WITH HIGH PRESSURE MOVING IN AFTER A COLD FRONT.
DISCUSSION
KEY MESSAGE 1: INCREASING HEAT AND HUMIDITY WILL BRING INCREASED
RISK FOR HEAT-RELATED ILLNESSES THURSDAY, AND ESPECIALLY ON
FRIDAY.
HEAT AND HUMIDITY STILL ON TAP FOR THE SECOND HALF OF THE WEEK.
THURSDAY SHOULD BE 4-5F HOTTER THAN WEDNESDAY, AND FRIDAY WILL
ADD ANOTHER 1-2F. WE'RE STILL KEEPING DAYTIME TEMPS A SHADE
COOLER THAN NBM MEAN GUIDANCE, LEANING HEAVILY ON THE RELIABLE
OL' MOS GUIDANCE AND MULTI-OFFICE ENSEMBLE OF FORECASTERS. THE
MAIN DRIVER OF THAT CHANGE IS THE EXPECTED HIGHLY-VARIABLE CLOUD
COVER AND OCCASIONAL SHOTS OF PRECIP. WARM FRONT DOES LOOK LIKE
IT WILL NUDGE PRECIP NORTHEASTWARD ON THURS, AND WE COULD HAVE
ENOUGH SUNSHINE TO KNOCK OUT THE FORECASTER BIAS. SO, THE
CHANGES ARE MINIMAL IN MAGNITUDE, ESPECIALLY WHEN CONSIDERING
THE DEWPOINTS, AS WELL. DEWPOINTS ARE PROGGED INT THE LOW 70S
ACROSS MUCH OF THE AREA, WHICH WILL FEEL QUITE UNCOMFORTABLE.
THE FORECAST APPARENT TS/HEAT INDICES FOR THURSDAY AND FRIDAY
STILL POKE ABOVE 100 FOR A FEW TOWNS AROUND
HARRISBURG/LANCASTER/YORK ON THURSDAY. FRI SHOULD BE 1-2F
HIGHER, AND MAY NECESSITATE A HEAT ADVISORY ISSUANCE FOR A FEW
COUNTIES. THE MAIN FORECAST UNCERTAINTY IS WHETHER OR NOT WE'LL
SEE WELL-TIMED STORMS ON THURSDAY OR FRIDAY AFTERNOON, WHICH
WOULD KEEP TEMPERATURE BELOW CRITERIA. BECAUSE OUR FORECAST JUST
BARELY TOUCHES 100F BOTH DAYS AND THERE REMAINS UNCERTAINTY
ABOUT STORM COVERAGE/TIMING, WE WILL CONTINUE TO HOLD OFF ON ANY
HEAT PRODUCTS FOR THIS PACKAGE. LREF CALIBRATED APPARENT T
GUIDANCE KEEPS THE PROBABILITY OF 100+ F HEAT INDEX VALUES
CAPPED AROUND 20% BOTH THURSDAY AND FRIDAY AFTERNOON IN THE FAR
SOUTHERN TIER (LOWER NORTHWEST), SO WE ARE COMFORTABLE TO
CONTINUE TO MESSAGE HOT/HUMID WEATHER BUT NOT YET SOUND THE
ADVISORY ALARM.
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KEY MESSAGE 2: DAILY SHOWER AND THUNDERSTORM CHANCES CONTINUE
THROUGH THE END OF THE WORK WEEK WITH DAMAGING WINDS POSSIBLE.
UNDERNEATH A BROAD RIDGE OF HIGH PRESSURE, A COUPLE SHORTWAVES
WILL DRIFT ACROSS PENNSYLVANIA OVER THE NEXT FEW DAYS.
SUFFICIENT INSTABILITY IN THE PRESENCE OF WARM & MOIST AIR ALONG
WITH VARIABLE AMOUNTS OF SHEAR WILL LEAD TO MULTIPLE ROUNDS OF
SHOWERS AND THUNDERSTORMS. THIS WILL BE A TYPICAL SUMMER-LIKE
PATTERN WITH MANY STORMS ON RADAR AND LINGERING QUESTIONS ABOUT
HOW STRONG THEY'LL GET. IF MULTICELL CLUSTERS CAN DEVELOP LARGE
ENOUGH COLD POOLS, AN ELEVATED THREAT OF DAMAGING WIND GUSTS MAY
MATERIALIZE IN THE FORM OF AN MCS. SUCH A SCENARIO CLOUD PRODUCE
A SWATH OF MORE SIGNIFICANT WIND DAMAGE (MOST LIKELY ON
THURSDAY).
A COLD FRONTAL PASSAGE (CFROPA) WILL OCCUR ON FRIDAY. DYNAMICS
IN THE FORM OF A DIGGING UPPER TROUGH, HIGH AVAILABLE MOISTURE
SUGGEST SEVERE THUNDERSTORMS ARE POSSIBLE. BUT, THE SMALL
RIDGE THAT PUMPS UP OVERHEAD LATE THU COULD BE A SETBACK FOR HOW
WIDESPREAD THE THREAT WILL BE. SPC HAS MAINTAINED THE SLIGHT
RISK FOR DAY 3 ACROSS ALL OF THE CWA. BIGGEST QUESTION IS
TIMING/SPEED OF THE COLD FRONT. A FASTER PROGRESSION COULD MEAN
THE COLD FRONT CLEARS OUR AREA BEFORE PEAK HEATING (LOWER THREAT
OF DAMAGING WINDS), WHILE A LATER ARRIVAL COULD SPELL MORE
CONCERN FOR SEVERE WEATHER. THE BEST MID- AND UPPER-LEVEL WINDS
WILL BE WELL TO THE NORTH OF PA PRECLUDING ANY HIGHER SEVERE
RISKS.
THE REPEATED SHOTS OF SCATTERED TO NUMEROUS SHRA/TSRA OVER THE
NEXT 3 DAYS IS LIKELY TO YIELD LOWER FFG THRESHOLDS AND SOME
FLASH FLOODING WOULD BECOME POSSIBLE, TOO. BUT, IT HAS BEEN VERY
DRY RECENTLY, AND EVERYTHING IS GROWING AND THIRSTY, READY TO
SOAK UP AS MUCH AS IT CAN. AS ALWAYS, TOO MUCH OF A GOOD THING
CAN BE BAD. WE'LL KEEP AN EYE ON THE SOIL SATURATION AND OTHER
FACTORS THAT COULD LEAD TO FLOODING. BACK-TO-BACK-TO-BACK
MARGINAL RISKS OF EXCESSIVE RAINFALL ARE IN PLACE THROUGH
FRIDAY.
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KEY MESSAGE 3: TEMPERATURE RELIEF NOT LARGE IN MAGNITUDE, BUT A
DECREASE IN HUMIDITY IS A GOOD BET WITH HIGH PRESSURE AFTER THE
COLD FRONT SAT/SUN.
THE COLD FRONT THAT PASSES THROUGH FRI/FRI NIGHT WILL SWEEP OUT
THE HUMID AIR, BUT REALLY FOR ONLY ONE OR TWO DAYS. RHS DIP INTO
THE 30S EACH AFTERNOON IN THE MOUNTAINS, AND LOWER 40S
ELSEWHERE OVER THE WEEKEND. HOWEVER, THE MAX TEMPS DON'T GET
BELOW NORMAL OVER THE WEEKEND. REGARDLESS, MORE SUNSHINE AND
LESS HUMIDITY WILL FEEL A BIT REFRESHING. PERHAPS ON DAYS 7 & 8
WE'LL BE A LITTLE COOLER, BACK TO NORMAL MAXES (75-83F) THANKS
TO A ZONAL FLOW ALOFT AND CLOUDS/PRECIP ARRIVING/PASSING
THROUGH. CFROPA ALSO AN INCREASING POSSIBILITY SOMETIME MON OR
TUES OF NEXT WEEK, AND COULD BRING ANOTHER BOUT OF SEVERE
WEATHER AND/OR HEAVY RAIN.
AVIATION /07Z WEDNESDAY THROUGH SUNDAY/
SCATTERED SHRA ACROSS PORTIONS OF SOUTHWESTERN PENNSYLVANIA
WILL TRACK CLOSE TO JST/AOO/UNV IN THE NEAR-TERM WITH MVFR
CEILINGS THE MOST LIKELY SCENARIO. IT IS OF NOTE THAT SOME MORE
RECENT OBSERVATIONS FILL IN QUITE QUICKLY WITH IFR CONDITIONS,
POTENTIALLY A LITTLE QUICKER THAN GUIDANCE MIGHT INITIALLY
INDICATE BASED ON MOST RECENT GLAMP/HREF/NBM MODEL GUIDANCE,
THUS HAVE DECIDED TO SPEED UP RESTRICTIONS SLIGHTLY BUT THESE
COULD STILL BE SLIGHTLY TOO SLOW, THUS LOW-TO-MODERATE (30-40%)
CONFIDENCE ON IFR TIMING AT THIS TIME. BIGGEST CHANGES TO THE
NEAR-TERM WERE TO QUELL TSRA MENTIONS OVERNIGHT GIVEN SLIGHTLY
LESS ELEVATED INSTABILITY AT PLAY ACROSS THE REGION BASED ON
MORE RECENT MESOANALYSIS AND FORECAST MODEL SOUNDINGS COMPARED
TO CURRENT OBSERVATIONS. THE 06Z TAF CYCLE ALSO RESOLVES SOME
DRYING DURING THE MORNING HOURS (BETWEEN 10-15Z WEDNESDAY)
BEFORE BRINING IN MORE WIDESPREAD CHANCES FOR SHRA/TSRA NEAR AND
AFTER 15Z WEDNESDAY.
RECENT HREF PROBABILITIES FOR PRECIPITATION MARKEDLY INCREASE
ACROSS W PA CLOSER TO 15Z, WITH RECENT GUIDANCE ALSO OUTLINING A
FAIR AMOUNT OF INSTABILITY. THIS TREND OUTLINES A PRETTY GOOD
SHOT OF SOME THUNDERSTORMS, ESPECIALLY IN THE 16Z-22Z TIMEFRAME
MOVING WEST-TO-EAST ACROSS THE FORECAST AREA. GREATEST CONCERN
WITH RESPECT TO TSRA WILL BE COVERAGE, THUS HAVE CONTINUED TO
OUTLINE THESE CHANCES IN PROB30S TO SEE HOW OBSERVATIONAL TRENDS
TREND CLOSER TO 12Z. IT DOES APPEAR AT THIS TIME THAT HIGHEST
POTENTIAL IS GENERALLY UNV/IPT/MST/LNS, THUS HIGHER POTENTIAL
FOR TEMPOS/FM GROUPS BEING ADDED IN FUTURE TAF PACKAGES. AS
PRECIPITATION TAPERS OFF, WILL NEED TO WATCH FOR PATCHES OF
CLEARING FOR SOME IFR/LIFR POTENTIAL OVERNIGHT, AS WINDS DO
TREND DOWNWARD; HOWEVER, TOO LOW OF CONFIDENCE TO TANK AIRFIELDS
MORE THAN MVFR AT THIS JUNCTURE.
OUTLOOK...
THU...RESTRICTIONS POSSIBLE IN SCATTERED -SHRA/-TSRA.
FRI...RESTRICTIONS EXPECTED AS FROPA BRINGS LINE OF -TSRA.
SAT...MAINLY VFR.
SUN...VFR FAVORED EARLY, WITH RESTRICTIONS POSSIBLE AS FROPA
BRINGS CHANCE OF -SHRA/-TSRA LATER IN THE DAY.
CTP WATCHES/WARNINGS/ADVISORIES
NONE.
WHAT HAS CHANGED...BANGHOFF
KEY MESSAGES...DANGELO/BANGHOFF
DISCUSSION...DANGELO/BANGHOFF
AVIATION...BEATY
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