677
FXUS61 KPBZ 030000
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
800 PM EDT THU OCT 2 2025
SYNOPSIS
DRY CONDITIONS AND ABOVE-NORMAL TEMPERATURE WILL PERSIST
THROUGH MONDAY. RAIN CHANCES WILL INCREASE ON TUESDAY.
NEAR TERM /THROUGH FRIDAY/
KEY MESSAGES:
- DRY AND SEASONABLE TONIGHT.
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THIS EVENING, CIRRUS CLOUDS ARE FORECAST TO MOVE INTO THE AREA.
COMBINED WITH A PERSISTENT LIGHT BREEZE OVERNIGHT, THERE IS A
LOW PROBABILITY FOR RIVER-VALLEY FOG DEVELOPMENT, SAVE A >10%
CHANCE FOR DUBOIS.
TOMORROW, THE LIGHT WIND WILL BECOME MORE SOUTHERLY, WHICH WILL
SLIGHTLY INCREASE RELATIVE HUMIDITY SINCE THE WIND WILL NO
LONGER BE COMING OFF THE APPALACHIANS. TOMORROW NIGHT, THE
WEAKENING HIGH WILL BE OFF THE MID-ATLANTIC COASTLINE, WITH A
BROAD RIDGE EXTENDING NORTHWARD INTO EASTERN CANADA AND WESTWARD
INTO SOUTHERN ILLINOIS. WINDS ARE EXPECTED TO EASE AS THEY
BECOME SOUTHEASTERLY. WITH THESE CALMER CONDITIONS AND THE
EXPECTED CLEAR SKIES, THERE IS A CHANCE FOR SOME PATCHY FOG
SATURDAY MORNING.
SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/
KEY MESSAGES:
- DRY CONDITIONS PREVAIL WITH A WARMING TREND.
- HIGH TEMPERATURES EXPECTED AROUND 5-10 DEGREES ABOVE NORMAL.
- CHANCE FOR FOG SATURDAY MORNING.
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WITH THE CHANCE FOR SOME FOG DEVELOPMENT, THERE WILL LIKELY BE
LINGERING MOISTURE AS IT LIFTS LATER IN THE MORNING. EVEN THOUGH THE
ATMOSPHERE WILL DRY DUE TO DOWNSLOPE WIND, THERE IS A LOWER
CHANCE FOR RELATIVE HUMIDITY TO GET AS LOW AS YESTERDAY/TODAY.
THERE IS HIGH CONFIDENCE IN THE RIDGE STRENGTH AND LOCATION,
WHICH WILL HELP TO MAINTAIN MOSTLY CLEAR SKIES AND START A
WARMING TREND. BY SATURDAY, THE DAYTIME HIGHS ARE FORECAST TO BE
10+ DEGREES ABOVE NORMAL WHILE OVERNIGHT LOWS WILL BE CLOSER TO
NORMAL WITH EFFECTIVE RADIATIONAL COOLING DUE TO CLEAR SKIES
AND LIGHT WINDS DURING THE NIGHT.
LONG TERM /SUNDAY THROUGH THURSDAY/
KEY MESSAGES:
- HIGH CONFIDENCE IN DRY AND WARM CONDITIONS THROUGH MONDAY.
- LOWER CONFIDENCE IN TEMPERATURES AND RAIN STARTING TUESDAY.
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LATEST LREF CLUSTER ANALYSIS POINTS TOWARD UNCERTAINTY IN THE
PATTERN STARTING ON TUESDAY WHEN AN UPPER-LEVEL TROUGH
TRANSITIONS INTO THE AREA FROM CANADA. THE ENSEMBLES ARE UNABLE
TO AGREE ON THE DEPTH/STRENGTH AND SPEED OF THE TROUGH,
RESULTING IN A RELATIVELY LARGE SPREAD IN ENSEMBLE TEMPERATURES
NEXT WEEK. THE CURRENT FORECAST SITS CLOSE TO ENSEMBLE MEANS,
WHICH ARE NEAR NORMAL THIS TIME OF YEAR.
TUESDAY INTO WEDNESDAY REMAINS THE MOST LIKELY TIME FOR THE
MENTIONED TROUGH TO IMPACT THE REGION WITH INCREASED PRECIPITATION
CHANCES. THE STRONGER THE TROUGH, THE HIGHER THE PROBABILITY FOR AT
LEAST 0.5 INCHES OF RAIN (40%-60%) WHILE THE FASTER TROUGH IS LIKELY
TO PRODUCE LESS RAIN.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
THE UPPER OHIO VALLEY WILL REMAIN, WITH HIGH PREDICTABILITY, ON
THE SWRN PERIPHERY OF SFC HIGH PRESSURE CENTERED IN NEW
ENGLAND. LIGHT ESELY WIND WILL RELAX OVERNIGHT IN TYPICAL
DIURNAL FASHION, AS A CIRRUS STREAM PROGRESSES EWD ACROSS THE
REGION. AFTER DEEP MIXING THIS AFTERNOON, AND WITH CIRRUS
LIMITING RADIATIONAL COOLING ENOUGH TO PREVENT WIDESPREAD
BOUNDARY-LAYER SATURATION, THERE APPEARS LITTLE LIKELIHOOD (10%
CHANCE NEAR KDUJ, LESS THAN 5% CHANCE AT ALL OTHER TERMINALS)
OF SUFFICIENTLY DEEP MOISTURE RECOVERY TO SUPPORT FOG FORMATION
OVERNIGHT.
THE CIRRUS SHIELD WILL EXIT ON FRI AND GIVE WAY TO A FEW
AFTERNOON DIURNAL CU DOTTING THE SKY, THOUGH BOUNDARY-LAYER
MOISTURE WILL BE SCARCE AMID ANOTHER DAY OF DEEP MIXING.
MOVEMENT OF THE SFC HIGH PRESSURE CENTER TOWARD THE SOUTHEAST
WILL REORIENT THE SFC PRESSURE GRADIENT, LEADING TO LIGHT SFC
WIND VEERING TOWARD THE SOUTH/SOUTHWEST.
OUTLOOK.
VFR CONDITIONS ARE EXPECTED ON THE WHOLE THROUGH MON AS HIGH
PRESSURE CENTERED IN THE NERN CONUS REMAINS ASSERTIVE. THE
EXCEPTION WILL BE DURING LATE NIGHT/EARLY MORNING SUN AND MON
WHEN RIVER-VALLEY FOG COULD ENSUE COINCIDENT WITH INCREASING
BOUNDARY-LAYER MOISTURE AND DIURNAL SLACKENING OF THE WIND.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...LUPO
NEAR TERM...MLB/MILCAREK/LUPO
SHORT TERM...LUPO
LONG TERM...LUPO
AVIATION...KRAMAR/MLB
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