747  
FXUS61 KPBZ 290046  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
846 PM EDT THU MAR 28 2024  
   
SYNOPSIS
 
 
HIGH PRESSURE BUILDING OVER THE UPPER OHIO RIVER VALLEY WILL  
BRING SEASONABLE TEMPERATURES AND MAINLY DRY WEATHER THROUGH  
FRIDAY. A SERIES OF LOW PRESSURE SYSTEMS ARE EXPECTED TO BRING  
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS SATURDAY THROUGH  
WEDNESDAY; HAZARDOUS WEATHER MAY DEVELOP.  
 

 
   
NEAR TERM /UNTIL 6 AM FRIDAY MORNING/
 
 
KEY MESSAGES:  
 
- A WEAK DISTURBANCE MAY PRODUCE LIGHT PRECIPITATION TO THE  
SOUTH OF PITTSBURGH OVERNIGHT.  
- SEASONABLE TEMPERATURES ARE FORECAST.  
 
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PREVIOUS DISCUSSION...  
 
A SHORTWAVE TRAVELING THROUGH A CROSSING UPPER TROUGH AXIS  
TONIGHT WILL LIKELY GENERATE SCATTERED LIGHT PRECIPITATION TO  
THE SOUTH OF PITTSBURGH OVERNIGHT, WITH BETTER CHANCES ALONG  
WEST-FACING SLOPES DUE TO UPSLOPE FLOW. GIVEN THERMAL PROFILES  
AND LIMITED MOISTURE MOSTLY BELOW THE DGZ, PRECIPITATION SHOULD  
MAINLY FALL AS LIGHT RAIN. IN THE HIGHER ELEVATIONS, THERMAL  
PROFILES SUGGEST A DUSTING OF LIGHT SNOW MAY BE POSSIBLE.  
TOWARDS MORNING, INVERSION HEIGHTS/MOISTURE MAY DROP ENOUGH TO  
SUPPORT SPOTTY FREEZING RAIN IN EASTERN TUCKER COUNTY, WITH  
MINIMAL IMPACT FORESEEN. ANY WINTRY ACCUMULATION (RAIN OR SNOW)  
WILL END FRIDAY MORNING.  
 

 
   
SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/
 
 
KEY MESSAGES:  
 
- DRY FRIDAY SAVE FOR THE WV RIDGES WITH EARLY WINTRY MIX POSSIBLE.  
- WIND ADVISORY IN EFFECT FOR EASTERN TUCKER COUNTY FRIDAY.  
- WIDESPREAD RAIN SHOWERS RETURN SATURDAY.  
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SHORTWAVE TROUGHING EXITS FRIDAY MORNING AS HEIGHTS RISE, ALBEIT  
BRIEFLY, AND DRY WEATHER RETURNS TO CLOSE THE WEEK SAVE FOR THE WEST  
VIRGINIA RIDGES WHERE UPSLOPE FLOW ACTING ON A MOIST, CONDITIONALLY  
UNSTABLE BOUNDARY LAYER WILL LIKELY SUPPORT LOW CLOUDS AND SOME  
LIGHT PRECIPITATION INTO THE LATE MORNING. ENSEMBLE PROBABILITIES  
LEAN TOWARD SNOW AS THE PRIMARILY PRECIP TYPE FOR THE MORNING  
HOURS, THOUGH WOULDN'T ENTIRELY RULE OUT A BRIEF MIX WITH SOME  
RAIN OR FREEZING RAIN DEPENDING ON SURFACE TEMPERATURES AS  
FORECAST SOUNDINGS SHOW THE DEPTH OF THE MOISTURE CUTTING OFF  
BELOW -10C. SPREAD IN ENSEMBLE TEMPERATURE IS SMALL, BUT  
HOVERING RIGHT AROUND THE FREEZING MARK. ANY IMPACTS WOULD MOST  
LIKELY BE CONFINED TO ELEVATED SURFACES, BRIDGES/OVERPASSES  
GIVEN WARM ANTECEDENT CONDITIONS. MOST LIKELY END TIME OF PRECIP  
IS AROUND 10-11AM AS DRY AIR FINALLY WINS OUT.  
 
THE OTHER NOTE FOR THE WEST VIRGINIA RIDGES WILL BE THE  
POTENTIAL FOR HIGH WIND GUSTS IN EASTERN TUCKER COUNTY ON FRIDAY.  
AS FLOW TURNS MORE WESTERLY, MODELS CONTINUE TO SHOW A 55-60 KT  
MOUNTAIN WAVE AT 850 MB JUST EAST OF TUCKER COUNTY FRIDAY  
MORNING INTO THE EVENING. NBM PROBABILITIES FOR ADVISORY  
CRITERIA (>46 MPH GUSTS) CONTINUE TO SIT AROUND 75-95% IN  
EASTERN TUCKER. STRONGEST GUSTS SHOULD REMAIN DOWNSTREAM GIVEN  
THAT THIS IS A NORTHWESTERLY FLOW EVENT, BUT EXPECT THE RIDGES  
TO GET QUITE WINDY WITH 45 TO 55 MPH GUSTS LIKELY AT THE DOLLY  
SODS MESONET SITE. FOR THESE REASONS, HAVE ISSUED A WIND  
ADVISORY FOR EASTERN TUCKER COUNTY FROM 4AM-8PM FRIDAY.  
 
OTHERWISE, IT WILL BE A SEASONABLE DAY WITH PLENTY OF SUN UNDER  
TRANSIENT HIGH PRESSURE AND WARM ADVECTION DRIVING HIGH TEMPERATURES  
INTO THE MID 50S (60-70% CHANCE SOUTHEAST OHIO TOPS 60 DEGREES).  
 
THE UPPER RIDGE QUICKLY FLATTENS ON SATURDAY AS THE FIRST IN A  
SERIES OF SHORTWAVES SLIDE IN FROM THE WEST. A WARM FRONT LIFTS  
THROUGH ON SATURDAY AND RESULTANT WARM ADVECTION DRIVE RAIN SHOWERS  
WILL ARRIVE EARLY IN THE MORNING CONTINUING THROUGH THE DAY AS THE  
COLD FRONT FOLLOWS QUICKLY BEHIND IT AND SINKS THROUGH SATURDAY  
NIGHT. RAINFALL AMOUNTS FOR THIS BATCH LOOK TO BE CONTAINED TO HALF  
AN INCH OR LESS, THOUGH A DEEPER TROUGH COULD PUSH THEM CLOSER TO  
0.6-0.7".  
 

 
   
LONG TERM /SUNDAY THROUGH THURSDAY/
 
 
KEY MESSAGES:  
 
- A SERIES OF WEAK LOW PRESSURE SYSTEMS WILL KEEP SHOWERS AND  
THUNDERSTORMS IN THE FORECAST FOR MUCH OF THE PERIOD.  
- PROBABILITIES INCREASING FOR RAINFALL TOTALS SATURDAY TO WEDNESDAY  
GREATER THAN 2", HIGHEST FROM MORGANTOWN TO TUCKER COUNTY WV.  
- ABOVE-AVERAGE TEMPERATURES ARE EXPECTED.  
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THE AFOREMENTIONED COLD FRONT THEN STALLS JUST TO OUR SOUTH AND  
KEEPS LOW CHANCE PRECIPITATION PRIMARILY SOUTH OF I-70 INTO EARLY  
SUNDAY MORNING. UNCERTAINTY REMAINS ON HOW FAR SOUTH IT STALLS WITH  
SOME ENSEMBLE SOLUTIONS STILL HOLDING RAIN CHANCES UP TO PITTSBURGH,  
SO WILL MAINTAIN SLIGHT CHANCE MENTION FURTHER NORTH UNTIL BETTER  
AGREEMENT COMES IN.  
 
THE FRONT THEN LIFTS BACK NORTH AGAIN SUNDAY NIGHT AS WARM ADVECTION  
IN SOUTHERLY FLOW RENEWS. WIDESPREAD RAIN AGAIN RETURNS AS LOW AND  
MID LEVEL FLOW WILL PARALLEL THE EAST-WEST ORIENTED BOUNDARY AS IT  
SITS ACROSS OUR AREA INTO MONDAY. RICH MOISTURE ARRIVES WITH PWAT  
VALUES NEARING 1.1" PUSHING THE DAILY MAX CLIMATOLOGICAL VALUE.  
ANOTHER DEEPER UPPER WAVE EJECTS OUT OF THE PLAINS LATE MONDAY AS  
LOW PRESSURE FORMS AND PLAGUES THE AREA THROUGH MID-WEEK.  
UNCERTAINTY COMES INTO PLAY WITH THE TIMING AND STRENGTH OF THE  
TROUGH AND THE TRACK OF THE SURFACE LOW WITH MOST ENSEMBLES  
HOLDING DOWNSTREAM RIDGING STRONG, BUT A LOWER PROBABILITY  
CHANCE EXISTS THAT A MORE ZONAL AND PROGRESSIVE PATTERN UNFOLDS.  
 
IN TERMS OF RAINFALL TOTALS, WPC HAS PLACED OUR CWA IN A MARGINAL  
(1/5) RISK FOR EXCESSIVE RAINFALL ON MONDAY. ENSEMBLE PROBABILITIES  
FOR >2" ARE INCREASING (40-70%), ESPECIALLY ACROSS WEST VIRGINIA,  
WITH HIGH END AMOUNTS OF 3-4" NOT OUT OF THE QUESTION. IN ADDITION,  
MACHINE LEARNING SHOWS INCREASING SEVERE WEATHER RISK MONDAY AND  
TUESDAY ACROSS THE OHIO VALLEY. THIS WILL LARGELY BE A QUESTION OF  
HOW MUCH INSTABILITY CAN MATERIALIZE AS OVERALL DYNAMIC PARAMETERS  
ARE SUFFICIENT TO SUPPORT THE POTENTIAL FOR SEVERE WEATHER. AT THIS  
TIME, ANALOGS HOLD THE THREAT JUST TO OUR SOUTHWEST, BUT UNCERTAINTY  
AS MENTIONED ABOVE COULD SHIFT THE THREAT FURTHER INTO OUR AREA.  
 

 
   
AVIATION /01Z FRIDAY THROUGH TUESDAY/
 
 
GUSTS ARE EXPECTED TO SUBSIDE AND REMAIN OUT OF THE WEST OVERNIGHT  
WITH THE ESTABLISHMENT OF A WEAK NOCTURNAL INVERSION. A WEAK  
WAVE WILL PASS SOUTH OF PIT, INCREASING CLOUD COVER OVERNIGHT,  
WITH SOME BROKEN VFR DECKS NOTED AT ZZV AND MGW. PROBABILITIES  
OF MVFR HAVE DECREASED TO JUST 10% AND ZZV AND 25% AT MGW. SOME  
ISOLATED SHOWERS ARE POSSIBLE EMBEDDED IN THE WAVE, THOUGH  
COVERAGE IS NOT ANTICIPATED TO BE LARGE ENOUGH TO JUSTIFY A  
PREVAILING OR TEMPO GROUP. PROBABILITY OF PRECIPITATION IS 15%  
AT BEST AND MOST LIKELY BETWEEN 06Z AND 12Z.  
 
CLEAR SKIES WILL PREVAIL TOMORROW BEHIND THE WAVE WITH MIXING  
ENCOURAGING GUSTS UP TO 20KTS, PEAKING DURING THE AFTERNOON.  
   
OUTLOOK
 
 
VFR IS EXPECTED THROUGH FRIDAY NIGHT UNDER HIGH PRESSURE.  
WIDESPREAD RESTRICTIONS AND SHOWERS RETURN SATURDAY WITH  
CROSSING LOW PRESSURE. VFR BRIEFLY RETURNS SUNDAY UNDER HIGH  
PRESSURE, BEFORE RESTRICTIONS IN SHOWERS/POSSIBLE TSTMS RETURN  
SUNDAY NIGHT AND MONDAY WITH A WARM FRONT.  
 

 
   
HYDROLOGY
 
 
WIDESPREAD ROUND OF RAINFALL ARE EXPECTED BEGINNING SATURDAY AND  
CONTINUING INTO THE MIDDLE PART OF NEXT WEEK. ENSEMBLE  
PROBABILITIES FOR >2" OF TOTAL RAINFALL ARE INCREASING  
(40-70%) AREAWIDE, BUT ESPECIALLY ACROSS WEST VIRGINIA, WITH  
HIGH END AMOUNTS OF 3-4" NOT OUT OF THE QUESTION THERE. THIS MAY  
RESULT IN AREAS OF FLOODING OR FLASH FLOODING, ESPECIALLY ON  
MONDAY, WHEN OUR AREA HAS BEEN PLACED IN A MARGINAL RISK (1/5)  
FOR EXCESSIVE RAINFALL.  
 
RISES ON AREA RIVERS FROM PROLONGED EXCESSIVE RAINFALL ARE ALSO  
LOOKING INCREASINGLY POSSIBLE AS ENSEMBLE PROBABILITIES  
CONTINUE TO TREND HIGHER BY THE BEGINNING OF NEXT WEEK.  
 

 
   
PBZ WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
OH...NONE.  
WV...WIND ADVISORY FROM 4 AM TO 8 PM EDT FRIDAY FOR WVZ514.  
 

 
 

 
 
SYNOPSIS...HEFFERAN/RACKLEY  
NEAR TERM...HEFFERAN/CL  
SHORT TERM...RACKLEY/MLB  
LONG TERM...MLB  
AVIATION...MILCAREK  
HYDROLOGY...MLB  
 
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