490
FXUS61 KPBZ 180041
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
841 PM EDT SAT APR 17 2021
SYNOPSIS
GENERALLY COOL AND DRY WEATHER IS EXPECTED THROUGH SUNDAY MORNING,
UNTIL ISOLATED SHOWERS RETURN SUNDAY AFTERNOON AND EVENING.
TEMPERATURE WILL GRADUALLY WARM THROUGHOUT THE NEXT FEW DAYS.
NEAR TERM /UNTIL 6 AM SUNDAY MORNING/
DIVERGENCE ALOFT AT 300MB COINCIDENT WITH COLD ADVECTION IN THE MID
LEVELS WILL SUPPORT LOW LEVEL FRONTOGENESIS AND SCATTERED SHOWERS
GENERALLY IN SE OH. ONCE THE JET STREAK ALOFT PROPAGATES TO THE
EAST, LARGE SCALE SUBSIDENCE SHOULD RESULT IN MOSTLY CLEAR SKIES AND
CALM WIND BY MORNING. AS SUCH, TEMPERATURE IS FORECAST IN THE MID TO
LOW 30S.
SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/
THE AFOREMENTIONED JET STREAK WILL BE MAINLY DISPLACED FROM THE OHIO
VALLEY ON SUNDAY, BUT VORTICITY ADVECTION WILL BE IN PLACE AND PROMPT
A SHORTWAVE PASSAGE SUNDAY AFTERNOON AND EVENING. AS THE SURFACE
WARMS AND MIXES, ELEVATED SHOWERS ARE POSSIBLE WITH MUCH COLDER AIR
ALOFT RESULTING IN MID-LEVEL LAPSE RATES OF 7-8C/KM.
SHORTWAVE RIDGING AND SWLY FLOW WILL ALLOW FOR A QUIET AND WARM
MONDAY.
LONG TERM /TUESDAY THROUGH SATURDAY/
LONG RANGE DETERMINISTIC MODELS INDICATE A LOW PRESSURE SYSTEM
UNDERGOING CYCLOGENESIS MAY MOVE SELY THROUGH THE GREAT LAKES MID TO
LATE WEEK, AND IF IT DOES, WILL LIKELY BRING SEVERAL PRECIPITATION FORCING
MECHANISMS INTO PLAY SUCH AS JET SUPPORTED ASCENT COINCIDENT WITH
FRONTOGENESIS AT THE SURFACE, AND VORTICITY ADVECTION. THIS SYSTEM
APPEARS AT THIS TIME TO USHER IN ANOTHER BRIEF INTERACTION WITH
TEMPERATURE BELOW THE CLIMATOLOGICAL NORM.
AVIATION /01Z SUNDAY THROUGH THURSDAY/
THE PASSAGE OF A SHORTWAVE TROUGH WL CONT TO SPAWN MVFR, TO LOW- END
VFR STRATOCU, AND SOME ISOLATED SHRA THIS EVE. THE SHRA ARE EXPECTED
TO RMN CONCENTRATED SOUTH OF I 70 WHERE UPR DIVERGENCE IS GENERATING
MID LEVEL FRONTOGENESIS. PASSAGE OF THE DISTURBANCE LATER TNGT WL
ALLEVIATE THAT CONCERN WITH THE SBSDNC ONSET DIMINISHING CLOUD COVER.
SHORTWAVE RIDGING WITH DECREASED WIND AND RESIDUAL LLVL MOISTURE MAY
SUPPORT SOME FOG, AND SOME ST AT FKL AND DUJ AS WEAK UPSLOPE IS
PROJECTED TO CONTINUE. THAT CONCERN WL BE BRIEF THOUGH AS ANOTHER
SHORTWAVE TROUGH IS PROJECTED TO INCREASE MID LVL CLD COVER AND BACK
THE WIND AS SUNDAY PROGRESSES. ISOLD, TO SCT SHRA ARE AGAIN POSSIBLE
WITH THAT DISTURBANCE.
OUTLOOK
RESTRICTIONS ARE PSBL AGAIN SUN NIGHT AND MON AS THAT TROUGH
COMPLETED PASSAGE AND A FRONTAL SYS ENCROACHES ON THE REGION.
PBZ WATCHES/WARNINGS/ADVISORIES
PA...NONE.
OH...NONE.
WV...NONE.
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