855
FXUS61 KPBZ 231813
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
213 PM EDT WED APR 23 2025
SYNOPSIS
PRECIPITATION CHANCES REMAIN LOW THROUGH THURSDAY UNDER
HIGH PRESSURE. SHOWER AND THUNDERSTORM CHANCES INCREASE FRIDAY
INTO SATURDAY. ABOVE AVERAGE TEMPERATURES EXPECTED THROUGH
EARLY NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
- DRY AND QUIET WEATHER THROUGH TONIGHT
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MINOR RIDGING ALOFT COMBINED WITH HIGH PRESSURE CENTERED OVER PA
WILL KEEP THE AREA DRY AND WARM TODAY AND TONIGHT. SUN IS
READILY AVAILABLE THIS AFTERNOON WITH LIMITED CLOUD COVERAGE AND
AS SUCH, HIGH TEMPERATURES ARE EXPECTED TO BE AROUND 10 DEGREES
ABOVE NORMAL.
LIGHT WINDS, LARGELY CLEAR SKIES AND ABOVE AVERAGE TEMPERATURES
ARE EXPECTED TO CONTINUE THROUGH THE OVERNIGHT HOURS. OVERNIGHT
LOWS ARE EXPECTED TO BE AROUND 5-10 DEGREES ABOVE THOSE SEEN
LAST NIGHT.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
KEY MESSAGES:
- DRY WEATHER THROUGH THURSDAY EVENING
- HOTTEST DAY OF THE WEEK THURSDAY
- RISK FOR SHOWERS AND STORMS INCREASES FRIDAY
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500MB HEIGHTS RISE FURTHER DURING THE DAYTIME ON THURSDAY AS A
DISJOINTED UPPER RIDGE SETTLES OVER THE TRI-STATE AREA.
EFFICIENT MIXING UNDER CLEAR SKIES AND A RELATIVELY DRY BOUNDARY
LAYER IS EXPECTED TO HELP HIGH TEMPERATURES ACROSS THE REGION
SURGE PAST 80 DEGREES. NBM PROBABILITIES OF HIGH TEMPERATURES
OVER 80 DEGREES ARE >70% SOUTH OF I-80 AND ARE NEAR 100% SOUTH
OF I-70. PROBABILITIES OF HIGH TEMPERATURES OVER 85 DEGREES ARE
HIGHEST ACROSS THE RIVER VALLEYS SOUTH OF PITTSBURGH (70-90%)
BUT EVEN SHOW A SIGNAL ACROSS SOME OF THE TERRAIN SOUTH OF I-70
(20-40%). THE SAME PROBABILITIES ACROSS PITTSBURGH GIVE DOWNTOWN
AN ALMOST 80% CHANCE TO CRACK 85 DEGREES WITH PROBABILITIES AT
THE AIRPORT PEAKING NEAR 60%. WE HAVE ALREADY SEEN SEVERAL DAYS
LIKE THIS SO FAR THIS SPRING AND SEEMINGLY EACH ONE HAS LANDED
ABOVE THE NBM 95TH PERCENTILE (LAST FRIDAY BROKE NBM 99TH
PERCENTILE) AND THE NBM 95TH PERCENTILE HIGH TEMPERATURES ARE 88
DOWNTOWN AND 86 AT THE AIRPORT.
AN UPPER TROUGH IS EXPECTED TO BE MOVING EASTWARD THROUGH THE
CENTRAL CONUS ON THURSDAY. ENSEMBLES HAVE COME TOGETHER ON PRIOR
PREDICTIONS FOR A WEAKER WAVE IMPINGING UPON THE OHIO RIVER
VALLEY ON FRIDAY. THE ASSOCIATED SFC LOW IS EXPECTED TO BE
ADVANCING THROUGH THE GREAT LAKES LATE THURSDAY NIGHT. A WEAK
FRONTAL SYSTEM DRAPED ACROSS THE AREA AND INCREASING MOISTURE IN
WARM ADVECTION WILL RETURN SHOWER CHANCES TO THE REGION
BEGINNING LATE THURSDAY NIGHT-EARLY FRIDAY MORNING. SHOWER AND
THUNDERSTORM CHANCES RISE AGAIN LATE FRIDAY AND PEAK FRIDAY
NIGHT AS THE ASSOCIATED COLD FRONT CROSSES THE AREA. SHOWERS ARE
EXPECTED TO END FROM WEST TO EAST LATE FRIDAY NIGHT WITH
RAINFALL TOTALS LARGELY BETWEEN 0.25-0.75 INCHES.
LONG TERM /SATURDAY THROUGH TUESDAY/
KEY MESSAGES:
- SHOWER CHANCES CONTINUE INTO SATURDAY MORNING
- TROUGH SPEED WILL DETERMINE TIMING OF RETURN TO ABOVE AVERAGE
TEMPS
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ENSEMBLES PROG THE COLD FRONT AS BEING NEAR OUR EASTERN CWA
BORDERS COME SUNRISE ON SATURDAY. SATURDAY IS EXPECTED TO BE
COOLER BEHIND THE FRONT AND POSSIBLY WINDY WITH A TIGHTENED
PRESSURE GRADIENT BEHIND THE DEPARTING LOW PRESSURE AND
ADVANCING HIGH PRESSURE. CLUSTERED ENSEMBLES INDICATE A STRONG
SIGNAL FOR A WEAKER AND FASTER TROUGH DEPARTURE SATURDAY BEFORE
SWITCHING SIGNS SUNDAY AS THE TROUGH DEEPENS AND SLOWS NEAR THE
EASTERN SEABOARD.
THIS ONCE AGAIN LEAVES THE DEGREE TO WHICH HEIGHTS RISE ON
SUNDAY SOMEWHAT IN QUESTION BUT EVEN WITH MINOR RISES IT SEEMS
LIKELY THAT DRY WEATHER RETURNS AND TEMPERATURES WARM. HEIGHTS
AND TEMPERATURES ARE EXPECTED TO CONTINUE TO RISE EARLY NEXT
WEEK AS THE CENTRAL CONUS RIDGE TRANSLATES EASTWARD BUT
CLUSTERED ENSEMBLES DISAGREE ON JUST HOW MUCH AS THEY CONTINUE
TO SHOW A STUBBORN TROUGH JUST OFF THE EASTERN SEABOARD.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
HIGH PRESSURE WILL ENSURE VFR CONDITIONS THROUGHOUT THE TAF
PERIOD. LIGHT WIND WILL REMAIN VARIABLE THROUGH TOMORROW
MORNING. DURING THE DAY TOMORROW, WIND WILL REMAIN LIGHT (4-6
KNOTS) COMING OUT OF THE SOUTH-SOUTHEAST.
OUTLOOK...
SHOWER AND THUNDERSTORM CHANCES WITH RISING RESTRICTION
PROBABILITIES WILL ACCOMPANY THE PASSAGE OF A LOW PRESSURE
SYSTEM STARTING LATE FRIDAY NIGHT INTO SATURDAY MORNING. THERE
IS HIGH CONFIDENCE IN VFR AND DRY WEATHER DEVELOPING BY SUNDAY
UNDER DRIER NORTHWEST FLOW AND BUILDING HIGH PRESSURE.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
SYNOPSIS...AK
NEAR TERM...AK
SHORT TERM...AK
LONG TERM...AK
AVIATION...RACKLEY/LUPO
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