Area Forecast Discussion
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FXUS61 KPBZ 311323
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
923 AM EDT TUE MAR 31 2015

.SYNOPSIS...
LOW PRESSURE TRACKING ACROSS THE REGION TODAY WILL BRING ANOTHER
ROUND OF PRECIPITATION. WARMER TEMPERATURES WILL ARRIVE FOR THE END
OF THE WORK WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
920 AM...CONTINUED PREVIOUS TREND OF MOVING LIKELY/CAT POPS A BIT
FURTHER NORTH GIVEN RAP/HRRR RUNS AND RADAR TRENDS. RAIN/SNOW LINE
IS HOLDING NORTH AS EXPECTED. DID NOT SIGNFICANTLY ALTER SNOW
EXPECTATIONS.  TWEAKS ELSEWHERE.

WITH 530AM UPDATE...HAVE EDGED GRADIENT FOR PRECIPITATION CHANCES
SLIGHTLY FARTHER TO THE NORTH. ALTHOUGH INITIAL BAND OF
PRECIPITATION CURRENTLY EXTENDS FROM PITTSBURGH TO THE
NORTH...BROADER SHIELD OF PRECIPITATION STILL REMAINS MOSTLY OVER
MICHIGAN AND LAKE ERIE. 06Z NAM AND 07Z HRRR ALSO SHOW THIS
CONTINUED SHIFT TO THE NORTH. IF THESE MODEL RUNS VERIFY...THEN
FORECAST OF LIKELY/CATEGORICAL POPS MAY STILL BE TOO FAR TO THE
SOUTH. PREVIOUS DISCUSSION FOLLOWS.

LOW PRESSURE WILL MOVE THROUGH THE REGION TODAY. SO FAR OVERNIGHT
THE TRACK OF THE LOW APPEARS TO BE SLIGHTLY FARTHER NORTH THAN
SYNOPTIC MODELS HAVE IN THE FORECAST. IMPLICATION WITH THE JOG TO
THE NORTH IS THAT WARMER AIR WILL BE PULLED SLIGHTLY FARTHER
NORTH...WHICH SHOULD REDUCE THE AREAL COVERAGE OF SNOWFALL IN OUR
AREA. IN ADDITION...THIS SHOULD ALSO SHIFT THE AXIS OF HEAVIEST
PRECIPITATION SLIGHTLY FARTHER TO THE NORTH AS WELL...CLOSER TO THE
NEW YORK/PENNSYLVANIA STATE LINE. FINALLY...THINK THAT MODELS ONCE
AGAIN ARE OVERDOING OVERALL LIFT IN THE STORM...WHICH IS LIKELY
CRANKING OUT TOO MUCH PRECIPITATION. IN THE END...DID NOT MAKE ANY
MAJOR CHANGES TO TODAYS FORECAST...WITH THE EXCEPTION OF SLIGHTLY
LOWERING SNOWFALL TOTALS WHERE SNOWFALL WILL OCCUR. AS THE LOW
TRACKS FARTHER TO THE EAST...CANNOT RULE OUT THE SLIGHT CHANCE OF A
THUNDERSTORM SOUTH OF INTERSTATE 70 LATER THIS AFTERNOON AS SOME
MODEST INSTABILITY WILL BE PRESENT. THE PASSAGE OF THE COLD FRONT
WILL ALSO BRING IN GUSTY WINDS...ESPECIALLY IN THE RIDGES WHERE
40-45 MPH WIND GUSTS WILL BE POSSIBLE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
A PASSING RAIN SHOWER WILL BE POSSIBLE ACROSS THE SOUTHEAST THIS
EVENING...BUT ALL PRECIPITATION WILL COME TO AN END BY MIDNIGHT. A
NEW WRINKLE TO THE FORECAST LATER TONIGHT INTO WEDNESDAY IS A WEAK
LOW PRESSURE SYSTEM THAT SHOULD TRACK NORTHEAST OF PITTSBURGH.
MODELS WERE NOT PICKING UP ON THIS FEATURE 24 HOURS AGO...BUT THE
SYSTEM IS CURRENTLY PRODUCING PRECIPITATION ACROSS CANADA. DID NOT
HAVE ENOUGH CONFIDENCE TO ADD ANY SNOW SHOWERS TO THE FORECAST...AS
ALL LOCATIONS SHOULD DROP BELOW FREEZING OVERNIGHT...BUT HAVE BUMPED
UP CLOUD COVER LATE TONIGHT INTO WEDNESDAY MORNING. SKIES SHOULD
THEN CLEAR UP WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING. THE CLEAR
SKIES WILL BE SHORT LIVED AS CLOUDS BEGIN TO INCREASE AGAIN IN
ADVANCE OF THE NEXT COLD FRONT APPROACHING THE REGION. STRONG
SOUTHWESTERLY WIND WILL RESULT IN GUSTY WINDS OF 20-30 MPH
THURSDAY...BUT WILL ALSO RAISE TEMPERATURES INTO THE 60S AND 70S.
CHANCES FOR RAIN WILL BE ON THE INCREASE DURING THE DAY...AND HAVE
ALSO ADDED THUNDER TO THE FORECAST AS WELL.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
DECENT PRECIPITATION CHANCES WILL CONTINUE INTO THE WEEKEND AS THE
FRONT SAGS ACROSS THE REGION AND PROVIDES FOCUS FOR SUBSEQUENT LOW
PRESSURE PASSAGE LATER ON FRIDAY...WITH AN EASTWARD EXIT ON
SATURDAY. CHANGES INCLUDE A UPWARD POP ADJUSTMENT TO CATEGORICAL
NUMBERS FOR THURSDAY NIGHT...AND FOR SOUTHERN COUNTIES ON FRIDAY.

A DRYING TREND IS INDICATED FOR THE WEEKEND ALTHOUGH A TRAILING
SHORTWAVE MAY GENERATE SOME SHOWERS ON SATURDAY. THE COOL DOWN
WILL NOT BE SIGNIFICANT THOUGH AS FLAT RIDGING IS ECMWF AND GFS
PROGGED TO BUILD AND MODERATE TEMPS FOR NEXT WEEK.

&&

.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
CONDITION DETERIORATION IS EXPECTED THIS MORNING WITH IFR AT FKL AND
DUJ AS LOW PRESSURE SPREADS RAIN AND SNOW OVER THE AREA.
OTHERWISE...GENERAL MVFR WITH RAIN IS ANTICIPATED FOR PORTS
SURROUNDING THE PIT AREA.

AS THE LOW CROSSES AROUND MID DAY AND AS SURFACE WARMING AND
COOLING ALOFT INCREASE THE DEPTH OF THE MIXING LAYER...SURFACE
WIND GUSTS WILL INCREASE TO AROUND 25 KTS WITH A DIRECTION VEER TO
THE NORTH...NORTHWEST.

MVFR STRATOCU ARE EXPECTED TO PERSIST INTO TUESDAY EVE AS COLD
ADVECTION ENSUES IN THE WAKE OF THE RAPIDLY EXITING SYSTEM.

.OUTLOOK.../WEDNESDAY THROUGH SATURDAY/...
MORE RESTRICTIONS ARE LIKELY WITH THE CROSSING OF LOW PRESSURE ON
LATE THURSDAY AND FRIDAY.

&&

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

&&

$$





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