Area Forecast Discussion
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FXUS61 KPBZ 230503 AAC
AFDPBZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
103 AM EDT WED JUL 23 2014

.SYNOPSIS...
A COLD FRONT WILL BRING SHOWERS AND STORMS TO THE AREA TODAY AND
THROUGH THE EVENING HOURS. COOLER AND DRIER AIR FOR THE REST OF
THE WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
MINOR CHANGES TO OVERNIGHT PERIOD. TWEAKED CLOUD COVER A BIT AND
UPDATED TEMPS TO LATEST GUIDANCE.

A COLD FRONT WILL RUSH THROUGH THE REGION TODAY. FRONT WILL
RECEIVE AND NICE PUSH FROM A STRENGTHENING SHORTWAVE TROUGH WHICH
WILL FOLLOW DIRECTLY BEHIND THE SURFACE BOUNDARY. MOST OF THE
SHOWER AND STORM ACTIVITY WILL BE RIGHT ALONG THE FRONT AND BEHIND
IN THE VICINITY OF THE TROUGH. ATMOSPHERE WILL QUICKLY DESTABILIZE
AS THE FRONT MOVES THROUGH. BECAUSE OF THE TIMING OF FRONTAL PASSAGE...
THE SOUTHERN HALF OF THE AREA WILL EXPERIENCE HIGHER INSTABILITY
LEVELS WITH SURFACE BASED CAPE OF 1500 TO 2000 J/KG AND A LIFTED
INDEX CLOSE TO -4. WOULD THINK THAT IF ANY STRONGER ACTIVITY
DEVELOPS...IT WOULD BE OVER THE SOUTH. SHEAR VALUES ARE NOT
IMPRESSIVE ONLY AROUND 20 TO 25KTS...AND WITH FRONT CLEARING THE
ENTIRE AREA BY 20Z...IT WILL NOT CROSS AT THE MOST OPTIMAL TIME.

EVEN THOUGH THE FRONT WILL PASS IN THE EARLY PART OF THE
AFTERNOON...WILL NEED TO KEEP IN POPS BEHIND THE FRONT WITH THE
PASSAGE OF THE STRONG SHORTWAVE.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...
IT WILL TAKE MOST OF THE EVENING FOR THE SHORTWAVE TO EXIT THE FAR
SOUTH. THIS WILL NECESSITATE LEAVING IN POPS ACROSS THE SOUTHERN
HALF THROUGH THE EVENING. ATMOSPHERE WILL BE STABILIZING SO EXPECT
THE THUNDERSTORM THREAT TO DIMINISH IN THE EVENING.

ANOTHER UPPER LEVEL DISTURBANCE WILL CROSS ON THURSDAY...BY THIS
TIME MOST OF THE MOISTURE WILL CONFINED TO LOCATIONS NEAR THE
MASON-DIXON LINE. WILL LEAVE IN THE MENTION OF SHOWERS THERE UNTIL
THE TROUGH PASSES LATE THURSDAY AFTERNOON.

COOLER AND DRIER AIR FOR THE ENTIRE REGION FRIDAY WITH SURFACE
HIGH MOVING IN AND THE UPPER LEVEL FLOW BECOMING MORE ZONAL.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LOW CONFIDENCE FORECAST FOR THE BEGINNING OF THE LONG TERM PERIOD.
MODELS EXPLORING SOME DIFFERENT OPTIONS WITH A SHORTWAVE TROUGH
THAT WILL CROSS THE AREA SOMETIME ON SATURDAY. THIS PART OF THE
FORECAST WILL NEED TO BE REFINED ONCE MODEL RUN TO RUN BECOMES
MORE CONSISTENT.

THE NEXT SYSTEM WILL BRING SHOWERS AND STORMS TO THE AREA SUNDAY
AND MONDAY AND MUCH COOLER AIR FOR THE END OF THE LONG TERM.

&&

.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
CLEARING TREND CONTINUES INTO THE OVERNIGHT HOURS WITH A COLD
FRONT STILL WELL TO THE WEST. TEMPERATURES AND DEWPOINTS ARE A FEW
DEGREES HIGHER THAN 24 HOURS AGO...BUT THE SPREAD BETWEEN REMAINS
ABOUT THE SAME. NOT EXPECTING CLOUDS ASSOCIATED WITH THE COLD
FRONT TO MAKE IT INTO THE AREA UNTIL AROUND SUNRISE WEDS...SO A REPEAT
OF MON NIGHT/TUES MORNING COULD BE IN STORE. IN SHORT...SHOULD
SEE DEVELOPMENT OF MVFR FOG FOR MOST TERMINALS...THE MORE FOG PRONE
TERMINALS COULD DROP TO IFR OR WORSE.

ANY OVERNIGHT FOG SHOULD QUICKLY DISSIPATE AFTER DAYBREAK WEDS AS
INCREASED SW SFC FLOW KICKS IN AHEAD OF THE COLD FRONT. RAIN
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE FRONT COULD CAUSE
SOME TEMPORARY RESTRICTIONS BEGINNING AROUND MIDDAY WEST THROUGH
THE LATE EVENING EAST. A WIND SHIFT WILL ALSO OCCUR WITH THE
FRONT...WITH 5-10KT WINDS FROM THE NORTHWEST WEDS EVENING.
TAX

OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
GENERAL VFR THURSDAY INTO SATURDAY AS HIGH PRESSURE RETURNS TO THE AREA.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$





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