022
FXUS61 KPBZ 062349
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
749 PM EDT MON OCT 6 2025
SYNOPSIS
DRY CONDITIONS WIND DOWN TONIGHT AS HIGH PRESSURE MOVES OFF THE
EASTERN SEABOARD. A PASSING COLD FRONT RETURNS RAIN ON TUESDAY,
FOLLOWED BY DRY AND COOLER CONDITIONS THE REMAINDER OF THE
WEEK.
NEAR TERM /THROUGH TUESDAY/
KEY MESSAGES:
- A SOAKING RAIN ARRIVES ON TUESDAY WITH A HIGH PROBABILITY FOR
AT LEAST 0.50-1.00 INCHES AREAWIDE
---------------------------------------------------------------
WITH SOUTHERLY FLOW PROMOTING WARM ADVECTION OVERNIGHT, LOWS
WILL ONLY DIP INTO THE UPPER 50S/LOW 60S. SOME VERY LIGHT, WARM
ADVECTION DRIVEN RAIN SHOWERS MAY ENCROACH ON EASTERN OH/FAR
WESTERN PA IN THE LATTER HALF OF THE OVERNIGHT HOURS, BUT WITH
PLENTY OF NEAR-SURFACE DRY AIR TO BATTLE, ANY THAT MAKES IT TO
THE GROUND WILL BE LIGHT.
DEEP LAYER SOUTHERLY FLOW CONTINUES PUMPING IN INCREASED
MOISTURE INTO THE MORNING HOURS ON TUESDAY. EXPECT THAT EARLY
MORNING SCATTERED SHOWERS WILL PREFACE MORE WIDESPREAD, STEADY
RAIN BY THE LATE MORNING AS INCREASED WARM ADVECTION/ISENTROPIC
ASCENT AND CONVERGENCE ALONG AND AHEAD OF A COLD FRONT INCREASE
FORCING. BY THIS POINT, PWAT VALUES ARE PROGGED TO REACH
1.5-1.75" WHICH IS ABOVE THE 95TH PERCENTILE OF CLIMATOLOGY.
GIVEN THE ONGOING WARM ADVECTION, DEEP LAYER PROFILES WILL BE
WELL-SATURATED AND NEAR MOIST ADIABATIC. THUS, IT'LL BE TOUGH TO
GET MUCH INSTABILITY GOING, BUT WARM RAIN PROCESSES WITH WARM
CLOUD LAYER DEPTH TO AROUND 13KFT SHOULD STILL ALLOW FOR
EFFICIENT RAINFALL. THE BEST OVERLAP OF FORCING AND MOISTURE
WILL BE IN THE LATE MORNING THROUGH THE EVENING, SO THAT SHOULD
BE OUR WINDOW FOR THE STEADIEST, WIDESPREAD RAIN.
SUBSEQUENT NBM RUNS CONTINUE BUMPING UP STORM TOTAL RAINFALL
AMOUNTS; PROBABILITY OF >0.5" IS AT 90+% AREAWIDE AND
PROBABILITY OF >1" BETWEEN 50-70%. EVEN NON-ZERO PROBABILITY FOR
>2" NOW REACHES AS HIGH AS ABOUT 20-30% SOUTH OF I-70 AND
10-20% IN STRIPS FARTHER NORTH. THE HREF AND REFS BOTH SUGGEST
LOCALIZED TOTALS AS HIGH AS 2" POSSIBLE AS WELL IN AREAS WHERE
HEAVIER RAIN TRAINS. BUMPING UP THE NEIGHBORHOOD RADIUS IN BOTH
ENSEMBLES (ACCOUNTS FOR SPATIAL UNCERTAINTY) SEES THESE PROBS
JUMP AS HIGH AS 30-50%, SUGGESTING THE CHANCE IS THERE, BUT THE
EXACT LOCATION REMAINS MORE QUESTIONABLE AND THESE AMOUNTS WOULD
BE HIGHLY LOCALIZED. DON'T SEE A WIDESPREAD FLOODING THREAT AS
THIS SHOULD ALL FALL ON A LONGER TIMESCALE WITH THE CHANCE OF
1"/HOUR RATES VERY LOW AND DRY ANTECEDENT CONDITIONS PRECLUDING
SUCH A THREAT. SOME ISOLATED ISSUES IN POOR DRAINAGE AND LOW
LYING AREAS ARE POSSIBLE WITH FALLING LEAVES TO EXACERBATE THIS
ISSUE. WPC HAS PLACED MUCH OF THE REGION NEAR AND SOUTH OF I-70
IN A SLIGHT RISK (LEVEL 2/4) FOR EXCESSIVE RAINFALL. WOULDN'T BE
SURPRISED TO SEE A FEW RUMBLES OF THUNDER, BUT THE POOR LAPSE
RATES AND VERY LOW INSTABILITY LENDS A LOW PROBABILITY.
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/
KEY MESSAGES:
- DECREASING RAIN CHANCES TUESDAY NIGHT INTO WEDNESDAY MORNING
- COOLER, DRIER AIR MASS FOR WEDNESDAY/THURSDAY OFFERING
POTENTIAL FOR MORNING FROST
----------------------------------------------------------------
RAIN WILL END FROM WEST TO EAST WITH FRONTAL PASSAGE ON TUESDAY
NIGHT. LINGERING LOW-LEVEL MOISTURE AND COLD ADVECTION WILL
LIKELY RESULT IN A STRATOCU DECK, BUT INCREASING DRY AIR SHOULD
ERODE THE CLOUDS BY WEDNESDAY MORNING AND ELEVATED WIND/LOWERING
DEW POINTS SHOULD PRECLUDE FOG DEVELOPMENT.
HIGH PRESSURE WILL QUICKLY FILTER IN BEHIND THE EXITING FRONT
AND OFFER A NOTABLE AIRMASS CHANGE FOR WEDNESDAY AND THURSDAY.
THE RESIDUAL PRESSURE GRADIENT AND DIURNAL MIXING WEDNESDAY MAY
GENERATE 20 TO 30MPH GUSTS DURING THE AFTERNOON BEFORE TAPERING
OFF WEDNESDAY NIGHT.
THE COOLER, DRIER AIR MASS WILL RESULT IN AFTERNOON HEIGHTS
NEAR (WEDNESDAY) TO BELOW AVERAGE (THURSDAY) DESPITE MOSTLY
SUNNY SKIES. THIS CHANGE ALSO CREATES POTENTIAL FROST AND
LOCALIZED FREEZE CONCERNS FOR LOW TEMPERATURE THURSDAY/FRIDAY AS
COOLER AIR PLUS RADIATIONAL COOLING LIKELY CREATES LOWS IN THE
30S AND 40S. THE KEY LIMITING FACTOR TO ANY FREEZING TEMPERATURE
OR FROST WILL BE POTENTIAL FOR ELEVATED NORTHERLY WINDS FROM
THE RESIDUAL PRESSURE GRADIENT THURSDAY MORNING (AND WARMER
DOWNSLOPE EAST WIND FRIDAY MORNING).
LONG TERM /FRIDAY THROUGH MONDAY/
KEY MESSAGES:
- DRY WEATHER FAVORED THROUGH THE WEEKEND, THOUGH PATTERN
VARIABILITY EXISTS
-------------------------------------------------------------------
THERE IS HIGH CONFIDENCE IN STRONG SURFACE HIGH PRESSURE
POSITIONING OVER THE NEW ENGLAND FRIDAY INTO THE WEEKEND AS THE
UPPER OHIO RIVER VALLEY SITS UNDERNEATH A WEAK, SAGGY TROUGH.
THIS WILL PROMOTE DRY WEATHER AND GRADUAL WARMING TO ABOUT 5
DEGREES ABOVE THE DAILY AVERAGE THROUGH THE PERIOD.
THERE REMAINS SOME UNCERTAINTY IN THIS AS A POTENTIAL
DEVELOPING/DEEPENING COASTAL LOW FORMS NEAR THE MID ATLANTIC AND
HAS POTENTIAL FOR INLAND MOVEMENT. IF CONFIDENCE IN THIS
SCENARIO EXISTS, AN UPWARD TREND IN PRECIPITATION CHANCES ALONG
WITH A DOWNWARD TREND TO TEMPERATURE (DUE TO INCREASED CLOUD
COVER) FOR EASTERN ZONES COULD OCCUR.
AVIATION /00Z TUESDAY THROUGH SATURDAY/
MID-LEVEL CLOUDS WILL CONTINUE TO INCREASE THIS EVENING AHEAD OF
AN APPROACHING COLD FRONT. RADAR SHOWS RETURNS ACROSS SOUTH
CENTRAL/WESTERN OHIO, BUT MOST OF THIS IS FALLING THROUGH DRY
AIR AT THE SURFACE AND NOT YET MAKING IT TO THE GROUND.
RESTRICTIONS WILL BEGIN TO CREEP INTO THE AREA FROM THE WEST TUESDAY
MORNING AS RAIN ARRIVES. LIGHT PASSING SHOWERS ARE INITIALLY
POSSIBLE AFTER 06Z AT ZZV, HLG, BVI, FKL, AND POSSIBLY PIT, BUT
CONTINUED TO CARRY PROB30S FOR THESE EARLY SHOWERS GIVEN DRY AIR
AND POOR MODEL CONSISTENCY. MOST LIKELY ARRIVAL TIME FOR THE
MORE STEADY RAIN IS AROUND 11Z FOR ZZV, 14Z FOR PIT AND RIGHT AT
THE END OF THE CURRENT TAF PERIOD FOR LBE.
GUIDANCE HAS BEEN A BIT MORE AGGRESSIVE WITH LOWERING CEILINGS
AT RAIN ONSET, BUT GIVEN LIMITED MOISTURE IN THE COLUMN, HAVE
SLOWED THIS A BIT. IT'S LIKELY WE MAY SEE HIGH END MVFR VIS
RESTRICTIONS IN RAIN WITH STILL LOW END VFR CIGS INITIALLY. MVFR
PROBABILITY IS 90+% IN THE RAIN WITH IFR CIG POTENTIAL ARISING
BETWEEN 20-00Z WHEN THE COLUMN FULLY SATURATES, SO CONFIDENCE IN
EVENTUAL RESTRICTIONS IS HIGH.
SOME STRATOCU LIKELY LINGER IN THE WAKE OF THE PASSING COLD FRONT
WITH LOW LEVEL COLD ADVECTION AND WIND WILL SHIFT TO THE NORTH-
NORTHWEST. DRY AIR SHOULD WORK IN BEHIND THE FRONT TUESDAY NIGHT AND
GRADUALLY ERODE THE CLOUDS BY WEDNESDAY MORNING.
OUTLOOK
VFR IS EXPECTED TO GRADUALLY RETURN WEDNESDAY AFTER FROPA, AND
CONTINUE THROUGH FRIDAY, AS HIGH PRESSURE BUILDS IN.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...MLB/AK
NEAR TERM...MLB/AK
SHORT TERM...FRAZIER
LONG TERM...FRAZIER
AVIATION...RACKLEY
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