411
FXUS61 KPBZ 080521
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1221 AM EST SAT NOV 8 2025
SYNOPSIS
GENERALLY DRY WEATHER IS EXPECTED THROUGH THE DAYLIGHT HOURS
SATURDAY BEFORE RAIN RETURNS SUNDAY WITH LOW PRESSURE. RAIN
WILL MIX WITH AND CHANGE TO SNOW SUNDAY NIGHT, WITH SNOW
SHOWERS AND MUCH COLDER TEMPERATURES MONDAY INTO TUESDAY.
NEAR TERM /THROUGH TODAY/
KEY MESSAGES:
- RAIN WILL TAPER OFF THROUGH MIDNIGHT.
- PATCHY FOG POSSIBLE MAINLY WEST OF I-79.
---------------------------------------------------------------
RAIN AHEAD OF A 700MB SHORTWAVE TROUGH WILL CONTINUE TO SHIFT
SOUTH AND EAST OF THE REGION TONIGHT AS BRIEF SUBSIDENCE PLUS
DRY ADVECTION WORKS IN FROM THE WEST. AT THE SURFACE, RESIDUAL
BOUNDARY LAYER MIXING AND WARM ADVECTION IN SW FLOW IS EXPECTED
TO LIMIT DIURNAL COOLING THROUGH THE EARLY PORTION OF THE
OVERNIGHT PERIOD. PASSAGE OF THE UPPER TROUGH AXIS EARLY
SATURDAY MORNING SHOULD PUSH THE WEAK COLD FRONT THROUGH THE
REGION, CREATING OVERNIGHT LOWS (THAT ARE STILL A FEW DEGREES
ABOVE AVERAGE) JUST PRIOR TO SUNRISE.
HEIGHTS ALOFT ARE EXPECTED TO QUICKLY RISE SATURDAY IN RESPONSE
TO DEVELOPING LOW PRESSURE OVER THE NORTHERN MISSISSIPPI RIVER
VALLEY. THIS SHIFT WILL STALL THE EARLY MORNING COLD FRONT
BEFORE LIFTING IT N/E DURING THE AFTERNOON AS A WARM FRONT AND
STALLING ITSELF AROUND NW PA. LOW PROBABILITIES EXIST FOR A
LIGHT RAIN SHOWER AHEAD OF THAT WARM FRONT (FAVORING LAKE ERIE-
ADJACENT LOCATIONS), BUT DRY WEATHER IS LIKELY FOR THE REST OF
THE REGION. WARM ADVECTION BEHIND THE FRONT SHOULD EQUATE TO
ABOVE NORMAL HIGH TEMPERATURE, BUT THERE MAY BE A SHARP
GRADIENT NEAR TO JUST NORTH OF PITTSBURGH WHERE THIS WARMING
STOPS (DUE TO COMBINATION OF LIMITED WARM ADVECTION DURATION
PLUS CLOUD COVERAGE) AND TEMPERATURE IS CLOSER TO THE SEASONAL
AVERAGE.
SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/
KEY MESSAGES:
- RAIN CHANCES INCREASE SATURDAY NIGHT INTO SUNDAY
- COLDER WITH RAIN MIXING WITH/CHANGING TO SNOW SUNDAY NIGHT
----------------------------------------------------------------
A DEEPENING UPPER TROUGH IS PROGGED TO DIG ACROSS THE UPPER
MIDWEST AND WESTERN GREAT LAKES SATURDAY NIGHT AND SUNDAY. AT
THE SFC, A DEEPENING LOW PRESSURE SYSTEM WILL TRACK FROM IL/IN
EASTWARD ACROSS THE OH VALLEY BY MID SUNDAY MORNING. RAIN
CHANCES BEGIN TO INCREASE CLOSEST TO THE LAKES FIRST, NEAR THE
ADVANCING WARM FRONT SATURDAY NIGHT. RAIN CHANCES THEN RAMP UP
ACROSS MUCH OF THE AREA SUNDAY MORNING AS THE LOW TRAVERSES THE
EASTERN GREAT LAKES AND DRAGS ITS TRAILING COLD FRONT THROUGH
OUR REGION.
AS THE FRONT CLEARS THE REGION SUNDAY AFTERNOON, WE WILL SEE
TEMPERATURES BEGIN TO FALL FROM HIGHS NEAR THE MIDDLE 50S IN
COLD ADVECTION.
SOME DECREASE IN THE RAIN CHANCES IS POSSIBLE SUNDAY AFTERNOON
AFTER FROPA. TEMPERATURES DROP QUICKLY AFTER MIDNIGHT SUNDAY
NIGHT AS RAIN MIXES WITH AND THEN TRANSITIONS TO SNOW. WITH WARM
GROUND TEMPERATURES AND PRIOR RAINFALL SUNDAY, ONLY MINOR
ACCUMULATIONS (A FEW TENTHS OF AN INCH) ARE EXPECTED BY SUNRISE
ON MONDAY, MAINLY ON GRASS AND ELEVATED SURFACES.
LONG TERM /MONDAY THROUGH FRIDAY/
KEY MESSAGES:
- MUCH COLDER WITH SNOW SHOWERS MONDAY INTO TUESDAY
- ACCUMULATION POSSIBLE MAINLY NORTH OF I-80 AND IN THE RIDGES
- UNSETTLED WEDNESDAY AND THURSDAY WITH OCCASIONAL RAIN/SNOW
CHANCES MAINLY NORTH OF PITTSBURGH
-------------------------------------------------------------------
ENSEMBLES CONTINUE TO POINT TOWARDS THE LONGWAVE TROUGH DIGGING
ACROSS THE EASTERN CONUS ON MONDAY. THERE REMAIN SOME
DIFFERENCES IN THE UPPER PATTERNS BETWEEN THE GEFS AND THE EURO
THAT WOULD MEAN DIFFERENT DURATIONS OF NW FLOW AND THUS
DIFFERING SNOW ACCUMULATIONS THROUGH TUESDAY. DESPITE THESE
DIFFERENCES, THE PICTURE REMAINS THE SAME THAT NW FLOW WILL
BRING SCATTERED TO NUMEROUS SNOW SHOWERS ACROSS PORTIONS OF THE
OH VALLEY.
850MB TEMPERATURES ARE EXPECTED TO DROP TO BETWEEN -8 TO -10
DEG C BY MONDAY, WHILE LAKE ERIE TEMPERATURES HOVER AROUND +12
TO +14 DEG C. LAKE AND TERRAIN ENHANCEMENT WILL BE LIKELY MONDAY
INTO PORTIONS OF MONDAY NIGHT AND POSSIBLY EARLY TUESDAY BEFORE
FLOW BACKS TO THE W AND THE MOST EFFICIENT LAKE AND TERRAIN
ENHANCEMENT IS TURNED NORTH OF THE REGION. MESOSCALE FEATURES
(SUCH AS A REINFORCING SURFACE TROUGH) WILL GREATLY AFFECT SFC
TO 850MB FLOW AND THUS THE POSITIONING, DURATION AND INTENSITY
OF ANY HEAVIER FOCUSED LAKE BANDS REMAINS LOW CONFIDENCE AT THIS
TIME. DESPITE THIS, MODELS CONTINUE TO HINT AT THE LIKELIHOOD
OF ONE OR SEVERAL LAKE BANDS YIELDING ENHANCED SNOWFALL NEAR AND
SOUTH OF LAKE ERIE. NBM PROBABILITIES CONTINUE TO EBB AND FLOW
BUT CURRENTLY SIT BETWEEN 40- 50% FOR ADVISORY LEVEL SNOW NORTH
OF I-80. THESE PROBABILITIES HAVE REMAINED RATHER STEADY FOR THE
PA AND WV RIDGES HOWEVER WHERE PROBABILITIES REMAIN BETWEEN
50-60%. WE WILL CONTINUE TO MONITOR THE EVOLUTION OF THIS SYSTEM
AND PATTERN OVER THE COMING FORECAST PERIODS.
THE TROUGH IS EXPECTED TO BEGIN TO SHIFT EAST OF THE AREA ON
TUESDAY, AS BOUNDARY LAYER FLOW BACKS TO THE SW AND SNOW CHANCES
DECREASE THROUGH THE DAY.
BROAD UPPER TROUGHING IS THEN EXPECTED TO PERSIST ACROSS AREAS
FROM THE UPPER MIDWEST INTO NEW ENGLAND. OCCASIONAL RAIN/SNOW
CHANCES WILL BE POSSIBLE, MAINLY NORTH OF PIT, AS INDIVIDUAL
SHORTWAVES ROTATE THROUGH THE TROUGH.
TEMPERATURES ARE EXPECTED TO BE 15 TO 20 DEGREES BELOW AVERAGE
MONDAY AND TUESDAY, BEFORE MODERATING SOME BY MID WEEK.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
SKIES WERE CLEARING FROM W-E AS A SHORTWAVE TROUGH EXITS THE
REGION. WITH LOW LEVEL MOISTURE IN PLACE, FOG AND STRATUS WAS
DEVELOPING AFTER THE CLEARING OCCURS. EXPECT LIFR TO DEVELOP
INITIALLY ACROSS OHIO AIRPORTS, WITH MVFR FURTHER EAST TO
PIT/AGC. ADDITIONAL MVFR STRATOCU WAS MOVING ESE TOWARD THE
REGION ALONG A SECONDARY SURFACE TROUGH/COLD FRONT. THESE SHOULD
MOVE OVER FKL AND DUJ OVERNIGHT, WHICH SHOULD PRECLUDE FOG
FORMATION.
MVFR IS EXPECTED FOR MOST AIRPORTS NORTH OF I-70 TODAY, OR NORTH
OF A ZZV-AFJ-VVS LINE AS THIS FRONT APPROACHES AND STALLS
ACROSS THE AREA. VFR IS EXPECTED TO THE SOUTH, WITH SCATTERED
CUMULUS AND CIRRUS ABOVE. CIGS SHOULD IMPROVE TO VFR THIS
EVENING AHEAD OF AN APPROACHING SHORTWAVE AND SURFACE LOW
PRESSURE.
OUTLOOK...
RESTRICTIONS ARE LIKELY SUNDAY IN RAIN AS LOW PRESSURE CROSSES
THE UPPER OHIO VALLEY REGION. PERIODIC RESTRICTIONS AND SNOW
SHOWERS ARE THEN EXPECTED SUNDAY NIGHT THROUGH TUESDAY AS A DEEP
UPPER TROUGH CROSSES THE REGION, AND LAKE/TERRAIN ENHANCEMENT
OCCURS. ANOTHER CROSSING TROUGH WILL MAINTAIN RESTRICTION
POTENTIAL WEDNESDAY, WITH RAIN AND SNOW POSSIBLE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...WM/FRAZIER
NEAR TERM...FRAZIER
SHORT TERM...AK
LONG TERM...WM/AK
AVIATION...WM
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page