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000
FXUS61 KPBZ 161149
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
749 AM EDT SUN JUN 16 2013

.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY...WITH THE POSSIBILITY
FOR PERIODIC RAIN CONTINUING MONDAY AND TUESDAY. CONDITIONS
SHOULD THEN DRY OUT FOR THE REST OF THE WORK WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
UPDATED PROBALIBILITES OF PRECIPITATION SLIGHTLY DUE TO RADAR
SHOWING MEASURABLE PRECIP FARTHER SOUTH

PREVIOUS DISCUSSION...
LINE OF SHOWERS AND THUNDERSTORMS ACROSS LOWER MICHIGAN AND
NORTHERN INDIANA HAS MANAGED TO HOLD UP FAIRLY WELL CONSIDERING
THE TIME OF DAY. HOWEVER...DO NOT THINK THIS LINE WILL BE ABLE TO
MAINTAIN ITSELF ALL THE WAY INTO NORTHEASTERN OHIO AND
NORTHWESTERN PENNSYLVANIA. 04Z HRRR INDICATES THE LINE MAY PASS TO
THE NORTH AROUND SUNRISE. NEVERTHELESS...SOME LIGHT SPRINKLES ARE
EXPECTED OVERNIGHT...AND COVERAGE OF SHOWERS WILL INCREASE AS THE
MORNING PROGRESSES. CONTINUED PREVIOUS FORECAST WITH LIKELY POPS
MOVING FROM NORTH TO SOUTH DURING THE DAY. CANNOT RULE OUT A
STRONG/SEVERE THUNDERSTORM...BUT AM NOT OVERLY IMPRESSED WITH THE
SETUP. MODEL SOUNDINGS SHOW MODERATE LEVELS OF INSTABILITY AND
SHEAR ALONG THE FRONT ITSELF...BUT LOOKING AT HIGH-RESOLUTION
MODEL REFLECTIVITIES...MOST OF THE PRECIPITATION WILL OCCUR WELL
AHEAD OF THE FRONT ITSELF. MODEL SOUNDINGS IN THE REGIONS WITH
PRECIPITATION SHOW A BIT LESS INSTABILITY DUE TO WEAK LOW-LEVEL
LAPSE RATES. WHILE SHOWERS WILL CONTINUE INTO THE EVENING...THINK
THAT MOST RAINFALL ACTIVITY WILL BE CONFINED TO LOCATIONS SOUTH OF
THE MASON-DIXON LINE AFTER MIDNIGHT. WITH THE WIDESPREAD CLOUD
COVER...DAYTIME TEMPS WILL BE A FEW DEGREES COOLER THAN
YESTERDAY...AND OVERNIGHT LOWS SHOULD BE SIMILAR TO CURRENT
READINGS.

&&

.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 SATURDAY/...
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 /12Z SUNDAY THROUGH THURSDAY/...
AN APPROACHING SHORTWAVE AND ASSOCIATED COLD FRONT WILL BRING
SHWRS AND INCRSD EMBEDDED TSTM CHCS TDA. FOR NOW...GIVEN A LACK OF
CONFIDENCE IN INSTABILITY PROGS...WL KP MENTION OF THUNDER OUT OF
ANY SPECIFIC TAF SITE. A GRADUAL DETERIORATION TO MVFR CAN BE
EXPECTED...WITH ISOLD IFR IN HEAVIER SHWRS.

.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.

&&

$$