716
FXUS61 KPBZ 182017
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
417 PM EDT TUE JUN 18 2013
SYNOPSIS
A COLD FRONT WILL SLOWLY MOVE SOUTHWARD THROUGH THE REGION
TONIGHT...BRINGING DRIER CONDITIONS FOR THE REST OF THE WEEK.
NEAR TERM /THROUGH WEDNESDAY/
THE COLD FRONT CONTINUES ITS SOUTHEASTWARD TROD EARLY THIS
AFTERNOON AND CURRENTLY EXTENDS FROM ROUGHLY ZANESVILLE TO
WHEELING TO PITTSBURGH. SHOWERS AND THUNDERSTORMS ARE FINALLY
DEVELOPING ALONG THE FRONT...AND WILL LIKELY CONTINUE TO INCREASE
IN COVERAGE/INTENSITY FOR THE NEXT COUPLE OF HOURS AS DIURNAL
INSTABILITY MAXIMIZES AND THE SHEAR PROFILE BECOMES MOVE
FAVORABLE.
THE FRONT WILL SLOWLY EXIT THE SOUTHERN PORTIONS OF THE AREA
TONIGHT...HOWEVER SOME DEGREE OF LOW LEVEL MOISTURE IS LIKELY TO
REMAIN IN ITS WAKE DUE TO A POOR MIXING PROFILE IN THE LOW LEVELS
BEHIND THE FRONT. AS SUCH...SOME FOG/STRATUS WILL BE POSSIBLE
ACROSS THE SOUTHERN PORTIONS OF THE AREA WEDNESDAY MORNING. ONCE
THE SUN RISES WEDNESDAY...THIS SHOULD QUICKLY MIX OUT. AFTER THAT
POINT...DRIER LAYER RH PROFILES MEAN A RETURN TO MOSTLY SUNNY
CONDITIONS BY AFTERNOON ACROSS THE AREA.
BEHIND THE FRONT...COLD ADVECTION AT 850 MB BRINGS 850 MB
TEMPERATURES DOWN TOWARD +10C WEDNESDAY AFTERNOON. WHILE THIS DOES
REPRESENT ROUGHLY 2C OF COOLING FROM TODAY...A BETTER MIXED
BOUNDARY LAYER AND LOW LEVEL LAPSE RATES CLOSER TO DRY ADIABATIC
WILL LIKELY ACTUALLY MEAN A WARMER DAY BEHIND THE COLD FRONT ON
WEDNESDAY. THE AREA AS A WHOLE LOOKS RATHER COMFORTABLE WITH LOWER
DEWPOINTS THAN TODAY...HIGHS SHOULD GENERALLY RUN INTO THE 70S.
THESE READINGS ARE AROUND HALF A DOZEN DEGREES BELOW NORMAL FOR
THIS TIME OF THE YEAR. FRIES
SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/
THERE IS GFS/ECMWF/NAM AGREEMENT THAT THE UPPER OHIO VALLEY WILL
BE IN A RELATIVELY DRY WEST-NORTHWESTERLY MID-LEVEL FLOW WITH HIGH
PRESSURE CENTERED NORTH OF THE AREA ON WEDNESDAY NIGHT. THE AREA
WILL REMAIN IN THIS PATTERN AS HIGH PRESSURE EXTENDING FROM THE
GREAT LAKES INTO THE MID-ATLANTIC CONTINUES TO DOMINATE THE
WEATHER PATTERN. THIS WILL ALLOW FOR ABUNDANT SUNSHINE FOR THE
MAJORITY OF THURSDAY AND FRIDAY. A SCHC OF THUNDERSTORMS ACROSS
THE RIDGES ON FRIDAY IS THE EXCEPTION...AS SOME ISOLATED DIURNAL
TERRAIN-DRIVEN THUNDERSTORMS WILL BE POSSIBLE THERE.
FOR TEMPS...FORECAST IS A FEW DEGREES HIGHER THAN A MAV/MET
BLEND ON THURSDAY...CONSIDERING ABUNDANT SUNSHINE WITH SUBSIDENCE
ALOFT. TEMPS ON FRIDAY WILL AGAIN BE A FEW DEGREES ABOVE NORMAL
AGAIN ON FRIDAY. OVERNIGHT LOWS WILL BE AROUND 5 DEGREES BELOW
NORMAL WEDNESDAY AND THURSDAY NIGHT WITH CLEAR SKIES AND NEAR CALM
WINDS SUPPORTIVE OF RADIATIONAL COOLING. FRIDAY NIGHT LOWS WILL BE
CLOSER TO SEASONAL NORMS AS WEAK LOW-LEVEL FLOW BECOMES MORE
SOUTHERLY.
LONG TERM /SATURDAY THROUGH TUESDAY/
WARM AND HUMID CONDITIONS ARE FORECAST INTO EARLY NXT WEEK AS BROAD
RIDGE IS STILL PROJECTED TO BLD OVR THE SRN AND ERN CONUS. HAVE
USED THE WARMER MOS GUIDANCE ONCE AGAIN FOR THE PD GIVEN CONSISTENT
HT PROGS AS DEPICTED BY GFS AND ECMWF MDLS OVR THE PAST CPL OF DAYS.
CHC/NR CLIMO POPS WERE ALSO INCLUDED THROUGH THE WEEKEND GIVEN THE
INSTABILITY THAT WL ACCOMPANY THE WARMTH AND MSTR...WITH LIMITATIONS
IMPOSED BY MID LVL CAPPING AND DEPENDENCY ON SHRTWV SPPRT ACRS THE
NRN PERIPHERY OF THE RIDGE.
AVIATION /20Z TUESDAY THROUGH SUNDAY/
SHOWERS AND THUNDERSTORMS HAVE BEGUN TO DEVELOP ALONG THE COLD
FRONT THAT IS SLICING THROUGH THE AREA THIS AFTERNOON CURRENTLY
FROM NEAR KZZV TO KHLG TO KAGC. AHEAD OF THIS BOUNDARY...COVERAGE
OF TS SHOULD INCREASE FOR THE NEXT FEW HOURS. IN
THUNDERSTORMS...CIGS/VIS WILL LIKELY DROP TO MVFR FOR A PERIOD.
OTHERWISE...VFR CONDITIONS SHOULD RETURN BEHIND THE FRONT. SOME
AREAS OF FOG WILL BE POSSIBLE IN THE OVERNIGHT/MORNING NEAR
KZZV...KHLWG...AND ESPECIALLY KMGW DUE TO RECENT RAINFALL. SKIES
SEEMS LIKELY TO CLEAR BY AFTERNOON WEDNESDAY. FRIES
OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
HIGH PRESSURE WILL BUILD INTO THE REGION. GENERAL VFR CONDITIONS
ARE EXPECTED.
PBZ WATCHES/WARNINGS/ADVISORIES
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page