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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 240120
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
920 PM EDT THU MAY 23 2013

.SYNOPSIS...
-- Changed Discussion --
SHOWERS WILL BECOME LESS NUMEROUS OVERNIGHT INTO EARLY FRIDAY
AS A COLD FRONT MOVES EAST OF THE REGION. MUCH COOLER AND DRY
CONDITIONS CAN BE EXPECTED FOR THE WEEKEND.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH FRIDAY/...
-- Changed Discussion --
COLD FRONT NOW THROUGH KPIT AND BEGINNING TO ACCELERATE TOWARD
THE RIDGES. UPDATE TO ADJUST POPS DOWN WEST OF PITTSBURGH AS ONLY
SCATTERED SHOWERS BEHIND FRONT IN COLD ADVECTION. REMOVED ANY
MENTION OF THUNDER AS INSTABILITY IS NOW TOO LOW. WINDS WILL BE
GUSTY FROM THE NORTHWEST THROUGH THE NIGHT BEHIND THE FRONT. MUCH
COLDER AIR WILL FLOOD INTO THE REGION WITH SHOWER CHANCES
DECREASING AS THE NIGHT PROGRESSES.

ON FRIDAY RATHER COLD NORTHWEST FLOW WILL KEEP A FEW SHOWERS IN
THE RIDGES OTHERWISE MUCH DRIER AIR AND COLD ADVECTION AT 850 MB
WILL KEEP TEMPERATURES MUCH BELOW NORMAL. SKIES WILL CLEAR ACROSS
THE ENTIRE REGION BY LATE DAY.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
COLDER AND MUCH DRIER AIR WILL CONTINUE TO RAPIDLY INVADE THE AREA
FRIDAY NIGHT WITH DEW POINTS RAPIDLY DECREASING THROUGH THE 40S
AND INTO THE LOWER 30S AND UPPER 20S BY SATURDAY MORNING. AS WIND
BACKS OFF FRIDAY NIGHT AND THE BOUNDARY LAYER DECOUPLES...CLEAR
SKIES WILL RESULT IN SUPERIOR RADIATIONAL COOLING. AS
SUCH...WIDESPREAD FROST IS LIKELY AND LOCAL FREEZING CONDITIONS
ARE POSSIBLE IN THE COLDER SPOTS.

WITH LITTLE OVERALL PATTERN EVOLUTION FROM FRIDAY NIGHT INTO
SATURDAY NIGHT AND SIMILAR RH PROFILES AND WIND PROFILES...YET
ANOTHER FROSTY NIGHT IS POSSIBLE SATURDAY NIGHT. BY
SUNDAY...SLIGHTLY WARMER 850 MB TEMPERATURES AND A TINY BIT OF
MIXING MAY ALLOW HIGHS TO START TO STRUGGLE UP MORE INTO THE 60S
RATHER THAN STRADDLING 60F ITSELF. FRIES

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
DRY WEA IS EXPD THRU THE PERIOD WITH HIGH PRESSURE IN CONTROL. A
WARM FRONT WILL APPROACH THE DISTRICT FOR WEDNESDAY INTO THURSDAY
BRINGING AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. TEMPS
WL START OUT BLO AVG OVR THE WEEKEND...THEN MODERATE TO SEASONAL
LVLS AS HIGH PRESSURE SHIFTS E OF THE AREA AND FLOW TURNS SRLY.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
SCATTERED SHOWERS CONTINUE TO MOVE EASTWARD WITH GENERAL VFR
CONDITIONS THIS EVENING. CEILINGS WILL LOWER TO MVFR AND EVENTUALLY IFR
AS STRATUS DEVELOPS OVERNIGHT. AS COLD FRONT CONTINUES TO CROSS
THE FORECAST AREA...WIND GUSTS ARE EXPECTED TO INCREASE WITH
NORTHWEST FLOW.


.OUTLOOK.../FRIDAY THROUGH TUESDAY/...
RESTRICTIONS ARE LIKELY WITH REMAINING STRATUS THROUGH EARLY
FRIDAY...BUT BUILDING HIGH PRESSURE WILL QUICKLY RETURN PORTS TO
VFR CONDITIONS BY FRIDAY AFTERNOON. GENERAL VFR WILL PERSIST INTO TUESDAY.

&&

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

&&

$$