510
FXUS61 KPBZ 141855
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
255 PM EDT WED APR 14 2021
SYNOPSIS
RAIN CHANCES WILL REMAIN SOUTH OF PITTSBURGH TODAY, WITH WIDESPREAD
RAIN POSSIBLE ON THURSDAY WITH CROSSING LOW PRESSURE.
NEAR TERM /THROUGH TONIGHT/
300MB JET DIVERGENCE EVIDENT ON SPC MESOANALYSIS AND ASSOCIATED LOW
LEVEL FRONTOGENESIS IS DRIVING RAIN SHOWERS SOUTH OF THE PA BORDER
THIS AFTERNOON. LIGHT, WIDESPREAD RAIN IS EXPECTED TO CONTINUE IN
THAT REGION THROUGH TONIGHT AS A COLD FRONT IS STALLED DUE TO ITS
RELATIVE POSITION IN AN OCCLUDING LOW PRESSURE SYSTEM.
GENERALLY, FOR THE REST OF THE OH VALLEY, SHORTWAVE RIDGING AND MUCH
DRIER AIR WILL ERODE CLOUD COVER RESULTING IN LOWER (THAN RECENT)
TEMPERATURE OVERNIGHT, BUT NEAR CLIMATOLOGICAL VALUE.
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
VORTICITY ADVECTION ASSOCIATED WITH THE AFOREMENTIONED LOW PRESSURE
WILL ARRIVE ALOFT IN THE REGION THURSDAY MORNING, AIDING ISO/SCT
SHOWER DEVELOPMENT, WITH THE HIGHEST CHANCE BEING NEAR I80 AND IN
HIGHER TERRAIN WITH AN UPSLOPE COMPONENT. THIS PRECIPITATION CHANCE
WILL LAST THROUGH FRIDAY, TAPERING GRADUALLY.
NOTABLY, A NWLY COMPONENT OF FLOW WILL USHER IN MUCH COLDER AIR, AS
850MB TEMPS PLUNGE TO -4 TO -6 DEG C. CONTINUED TREND TO SIDE WITH
LOWER TEMPERATURE GUIDANCE AS A RESULT, WITH MANY LOCATIONS
STRUGGLING TO REACH 50 DEGREES. THERMAL PROFILES SUGGEST PORTIONS OF
THE I-80 CORRIDOR AND HIGHER TERRAIN COULD SEE SNOW MIXED IN AMID
CONTINUED COLD ADVECTION FRIDAY MORNING, BUT ACCUMULATION WILL BE
LIGHT AND LIMITED TO THE RIDGES OF WV.
DRY CONDITIONS AND A CLEARING SKY IS GENERALLY EXPECTED FRIDAY NIGHT
WITH INCREASING SUBSIDENCE AND HEIGHT RISES AS THE UPPER LOW SHIFTS
TOWARD THE ATLANTIC.
LONG TERM /SATURDAY THROUGH TUESDAY/
PERIODIC RAIN CHANCE WITH NEAR TO SLIGHTLY BELOW SEASONAL AVERAGE
TEMPERATURE IS LIKELY INTO EARLY NEXT WEEK AS A PROGRESSIVE FLOW
ALLOWS FOR A SERIES OF SHORTWAVES TO IMPACT THE REGION.
AVIATION /19Z WEDNESDAY THROUGH MONDAY/
VFR SHOULD PREVAIL AT MOST PORTS GIVEN DRY LOWER LEVELS AS NOTED IN
RECENT SFC DEWPOINT OBS, INFLUENCED BY WEAK LLVL SHORTWAVE RIDGING.
THE EXCEPTION WOULD BE NEAR MGW, WHERE SFC CONVERGENCE AND ASSOCIATED
RIGHT ENTRANCE JET STREAK ASCENT SHOULD MAINTAIN SHOWERS AND
POTENTIAL MVFR THROUGH TONIGHT. INTENSIFYING PRESSURE GRADIENT WILL
SUPPORT INCREASING WIND TOWARDS THE END OF THE TAF PERIOD.
OUTLOOK
PERIODIC RESTRICTIONS AND RAIN CHANCES ARE LIKELY THROUGH FRIDAY AS
AN UPPER TROUGH DEEPENS OVER THE REGION.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
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