Area Forecast Discussion
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FXUS61 KPBZ 042217
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
617 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/...
MADE SOME CHANGES TO POPS BASED ON RADAR AND NEAR-TERM MODEL
TRENDS. STILL EXPECT DEFORMATION ZONE TO TAKE ON MORE OF A
NORTHWEST/SOUTHEAST ORIENTATION WITH TIME THIS EVENING AND
OVERNIGHT AS THE UPPER LOW DIGS SOUTH. FOCUS WILL BE ON THE
SOUTHEAST CWA AFTER 06Z. WILL KEEP AN EYE ON RAINFALL TOTALS IN
THIS AREA AS FLASH FLOOD GUIDANCE IS RELATIVELY LOW...PARTICULARLY
IN MARION/MONONGALIA COUNTIES. STILL THINK RAINFALL RATES WILL NOT
BE SUFFICIENT TO CAUSE SIGNIFICANT PROBLEMS. WILL CONTINUE
ISOLATED THUNDER MENTION INTO THIS EVENING AS WELL. CL

PREVIOUS DISCUSSION FOR THURSDAY...

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 /THURSDAY NIGHT 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 /22Z 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.

&&

$$



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