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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KPBZ 161834
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
234 PM EDT SUN JUN 16 2013

.SYNOPSIS...
-- Changed Discussion --
A WEAK DISTURBANCE WILL PUSH EAST OF THE AREA TODAY...BRINGING SHOWERS
AND POSSIBLY AN ISOLATED THUNDERSTORM. A FRONTAL BOUNDARY WILL SAG
SOUTHEASTWARD INTO THE AREA TONIGHT INTO MONDAY...WITH A LOW
CHANCE FOR SHOWERS THROUGH THIS PERIOD. THE FRONT WILL PUSH
SOUTHEAST OF THE AREA LATE ON TUESDAY AND HIGH PRESSURE WILL THEN
BUILD IN FROM THE NORTHWEST AND ALLOW FOR A DRY MID-WEEK.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
18Z ENHANCED SHORT TERM FORECAST HAS BEEN ISSUED TO REDUCE POPS AS
INITIAL WAVE OF SHOWERS PUSHES EAST OF THE AREA.

THE LATEST RAP UPPER LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY
IN A ZONAL FLOW WITH A 300MB 100KT JET AXIS CENTERED OVER LAKE
HURON. AT THE MID-LEVELS...A 500MB SHORT WAVE IS WEAKENING AS IT
MOVES EASTWARD INTO WESTERN PA. AT THE SURFACE...A 1005MB SURFACE
LOW IS LOCATED NORTH OF LAKE SUPERIOR WITH A ILL-DEFINED FRONTAL
BOUNDARY EXTENDING SOUTH OF THIS FEATURE ACROSS SOUTHERN MICHIGAN.
WELL AHEAD OF THE FRONT...WEAK 700-500MB VORT ENERGY ALONG WITH A
MOIST 800-650MB LAYER ARE SUPPORTING SCATTERED SHOWERS MOVING
EAST OF THE AREA.

THIS AFTERNOON AND EVENING...THE SHORT WAVE WILL CONTINUE TO
WEAKEN AS IT MOVES INTO CENTRAL PENNSYLVANIA. MEANWHILE...THE
FRONTAL BOUNDARY WILL SAG FURTHER SOUTHEASTWARD INTO THE AREA. AS
FORCING FROM THE WAVE MOVES EASTWARD...SHOWERS WILL DIMINISH IN
COVERAGE. EXTENSIVE UPSTREAM CLOUD COVERAGE WILL CONTINUE TO
INHIBIT CONVECTIVE TEMPS FROM BEING REACHED. THUS...HAVE GONE WITH
CHC SHOWERS AND SCHC THUNDERSTORM WORDING TO NOT COMPLETELY DISCOUNT
THE HRRR/WRF-NMM SOLUTIONS. WITH ALL OF THIS IN MIND...THE STORM
PREDICTION CENTER STILL HAS THE AREA MENTIONED IN ITS SEE TEXT.
TEMPS HAVE BEEN LOWERED A FEW DEGREES CLOSER TO LAMP
GUIDANCE...WITH HIGHS RANGING FROM THE LOWER TO MID TO UPPER 70S
ACROSS THE AREA.

TONIGHT...THE FRONTAL BOUNDARY WILL CONTINUE TO SAG SOUTHEASTWARD
ACROSS THE AREA...WITH ANY LINGERING COVERAGE OF SHOWERS MOSTLY
DIMINISHING BY 06Z. MOSTLY CLOUDY SKIES WILL BEGIN TO GIVE WAY TO
MORE BREAKS IN CLOUD COVERAGE WITH SHOWERS COMING TO AN END AS A
POCKET OF DRIER AIR ADVECTS IN FROM THE NORTHWEST. CLOUD COVERAGE
FOR MUCH OF THE NIGHT WILL SERVE TO MODERATE LOW TEMPS. FORECAST IS
CLOSEST TO THE WARMER MAV...WITH LOWS RANGING FROM THE LOWER TO MID
60S ACROSS THE AREA.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
HAVE BACKED OFF POPS ON MONDAY DOWN TO SLIGHT CHANCE. FORECAST AREA
SHOULD BE IN THE DRY REGION BETWEEN FRONTS TO THE NORTH AND
SOUTH...AND DO NOT SEE MUCH OF A TRIGGER TO GET PRECIP GOING. MONDAY
NIGHT AND TUESDAY THE NAM/SREF ARE AGGRESSIVE SWEEPING THE NORTHERN
FRONT ACROSS THE REGION AND BRINGING WIDESPREAD PRECIPITATION. WITH
THE ECMWF SHOWING MORE CONSISTENCY...KEEPING THE NORTHERN FRONT DRY
AND FOCUSING PRECIPITATION ALONG THE SOUTHERN FRONT...AND THE GFS
AND GEFS COMING INTO LINE WITH THE ECMWF SOLUTION...HAVE BACKED OFF
POPS ACROSS THE NORTHERN HALF OF THE REGION FOR MON NIGHT/TUES.
ONCE THE FRONT MOVES OFF TO THE EAST...THE ENTIRE AREA SHOULD BE
DRY TUESDAY NIGHT AND WEDNESDAY WITH HIGH PRESSURE MOVING IN FROM
MICHIGAN. LIGHT NORTHERLY FLOW THROUGH THIS TIME PERIOD SHOULD
KEEP TEMPERATURES A FEW DEGREES BELOW NORMAL.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
LATEST GFS AND ECMWF DETERMINISTIC SOLNS AGREED GENLY IN
DEPICTIONS OF THE PROGGED FLOW PTN OVR THE ERN CONUS FOR THE
LATTER HALF OF THE WEEK...WITH ECMWF AMPLIFYING THE PTN CLOSER TO
GFS WITH A RIDGE AXIS EXTENDING FM THE SRN PLNS ACRS THE GREAT
LAKES.

THE LONG TERM FORECAST THUS CONSERVATIVELY FEATURES TEMPS
GRADUALLY WARMING TO SLIGHTLY ABOVE THE SEASONAL AVERAGES BY THE
WEEKEND. PCPN CHCS WERE FORECAST AOB CLIMO NMBRS...BUT WERE GENLY
INCRSD USING A GFS/ECMWF BLEND FOR SHRTWV TIMING INTO THE WEEKEND.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
CURRENTLY GENERAL MVFR CONDITIONS AT MOST SITES WITH RAIN
SHOWERS. GRADUALLY IMPROVING CONDITIONS CAN BE EXPECTED AS A WEAK
COLD FRONT CONTINUES MOVING SOUTHEAST THROUGH REGION. CIGS SHOULD
GRADUALLY IMPROVE TO VFR EVERYWHERE THIS EVENING WITH PARTIAL
CLEARING TONIGHT. SLIGHTLY DRIER AIR GRADUALLY MOVING IN BUT WITH
WET CONDITIONS OVER THE AREA AND DEWPOINTS ONLY DROPPING SLIGHTLY WILL
LIKELY SEE SOME FG/BR TO DEAL WITH MONDAY MORNING AT SOME TAF SITES.

.OUTLOOK.../MONDAY THROUGH THURSDAY/...
PERIODIC RESTRICTIONS ARE ANTICIPATED THROUGH TUESDAY AS ANOTHER
LOW APPRCHS AND CROSSES THE REGION. BLDG HIGH PRES SHOULD RTN VFR
CONDITIONS FOR WEDNESDAY AND THURSDAY.

&&

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

&&

$$

SYNOPSIS...WOODRUM
NEAR TERM...WOODRUM