Area Forecast Discussion
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000
FXUS61 KPBZ 041951
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
351 PM EDT WED MAY 4 2016

.SYNOPSIS...
PERSISTENT LOW PRESSURE WILL MAINTAIN SHOWERS IN THE FORECAST
THROUGH FRIDAY. RAIN CHANCES RETURN SATURDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
LATEST RADAR IMAGERY SHOWS SCATTERED ACTIVITY ACROSS THE FORECAST
AREA...WHICH IS EXPECTED TO CONTINUE THROUGH THE AFTERNOON AS THE
UPPER LOW CONTINUES TO DEEPEN TO THE WEST. ALTHOUGH THERE IS VERY
LIMITED CAPE...STEEP LOW-LEVEL LAPSE RATES COMBINED WITH A LOW
FREEZING LEVEL WILL RESULT IN ISOLATED LIGHTNING AND PEA-SIZED
HAIL OUT OF SOME OF THE LOW-TOPPED CELLS. THERE IS NO RISK OF
SEVERE WEATHER. SHOWERS WILL CONTINUE THROUGH THE NIGHT AND BECOME
MORE WIDESPREAD AS THE UPPER LOW CONTINUES TO SHIFT SOUTH AND THE
FORECAST AREA SITS UNDER THE DEFORMATION ZONE. THURSDAY WILL SEE
CONTINUED SCATTERED SHOWERS AS THE UPPER LOW CENTER SLOWLY MOVES
EAST ACROSS NORTH CAROLINA. TEMPERATURES ARE FORECAST TO BE 10
DEGREES BELOW NORMAL ON AVERAGE ACROSS THE REGION.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
THE H5 CLOSED LOW MENTIONED ABOVE WILL MEANDER AROUND THE MID-
ATLANTIC REGION THROUGH AT LEAST FRI NIGHT...WITH VORTICITY LOBES
CIRCUMNAVIGATING THE SYSTEM. THESE WAVES WILL SUPPORT SHOWERS IN
THE SERN ZONES AND ESPECIALLY IN THE RIDGES ON THU NIGHT...WHERE
MODEST UPSLOPE FLOW WILL ENHANCE PRECIPITATION POTENTIAL.

BRIEF SHORTWAVE RIDGING ON SATURDAY WILL HELP DIVERT THE UPPER
LOW AND BRING AN END TO THE PRECIPITATION FOR SAT AFTERNOON. A
STRONG SHORTWAVE TROUGH DIGGING INTO THE WRN GREAT LAKES REGION
WILL SHUNT THE UPPER RIDGE SEWD...WITH PRECIPITATION CHANCES
CONSEQUENTLY INCREASING SAT NIGHT AS THE ASSOCIATED COLD FRONT
APPROACHES AND CROSSES THE REGION.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
PRECIPITATION SAT NIGHT WILL EXIT QUICKLY BY SUN MORNING IN THE
WAKE OF THE GREAT LAKES SHORTWAVE TROUGH. ALTHOUGH LITTLE
PRECIPITATION IS EXPECTED ON SUN...THE REGION WILL REMAIN ON THE
NRN SIDE OF A STALLED FRONTAL BOUNDARY. THUS...MAXIMA WILL REMAIN
SLIGHTLY-BELOW NORMAL IN THE LOW-MID 60S.

A STRONG LOW PRESSURE SYSTEM THAT HAD BEEN LOCATED IN THE SWRN
CONUS THROUGH THE WEEKEND WILL EJECT SLOWLY INTO THE MISSISSIPPI
RIVER VALLEY BY EARLY NEXT WEEK...LEADING TO AN AMPLIFYING RIDGE
OVER THE ERN CONUS AND ATTENDANT INCREASE IN WARM AIR BEGINNING ON
MON. NEAR-CLIMATOLOGICAL POPS WERE INCLUDED IN THE FORECAST DURING
THIS TIME AS THE FCST AREA WILL RESIDE IN THE MOIST WARM SECTOR.

ALTHOUGH THERE IS TIMING DISAGREEMENT AMONG THE MEDIUM-RANGE
MODELS...A COLD FRONT IS EXPECTED TO APPROACH THE REGION LATE
WED/THU AS THE AFOREMENTIONED UPPER-LEVEL LOW APPROACHES THE
REGION. GIVEN THE TIMING DIFFERENCES...THIS COMBINATION OF
FEATURES WARRANTS GENERAL HEIGHTENED POPS AND INCREASED CLOUD
COVER DURING ITS TENURE IN THE REGION.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR THE REMAINDER OF THE DAY UNTIL CONDITIONS DETERIORATE THROUGH
THE EVENING AS AN AREA OF LOW PRESSURE MOVES OVER THE REGION.
MVFR AND OCCASIONAL IFR WILL THEN BE LIKELY THROUGH THURSDAY
NIGHT.

.OUTLOOK /THURSDAY THROUGH SUNDAY/...
PERIODIC RESTRICTIONS ARE LIKELY THU/FRI WITH PERSISTENT LOW
PRESSURE...AND AGAIN WITH A COLD FRONT ON SAT NIGHT.

&&

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

&&

$$

MK/KRAMAR


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