Area Forecast Discussion
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FXUS61 KPBZ 260205
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1005 PM EDT MON MAY 25 2015

.SYNOPSIS...
WARMTH AND HUMIDITY HAVE RETURNED TO THE UPPER OHIO VALLEY
REGION...BUT SHOWER AND THUNDERSTORM CHANCES CAN BE EXPECTED FOR
MOST OF THE COMING WEEK.

&&

.NEAR TERM /THROUGH TUESDAY/...
THE UPDATE FOR THE EVENING FEATURES FAIRLY SMALL ADJUSTMENTS TO
POPS AS A WEAK VORT RIBBON MOVING ACROSS EASTERN OHIO WITH STRONG
SOUTHWESTERLY FLOW AND WARM ADVECTION HAS YIELDED NO THUNDERSTORM
ACTIVITY DUE TO WARM TEMPERATURES ALOFT. LIKEWISE...WHAT MEAGER
SHOWERS DID MANAGE TO BE MUSTERED DURING THE EVENING HAVE
DISSIPATED AT THIS HOUR.

THE FORECAST THINKING OF ANOTHER INCREASE IN POPS TOWARD MORNING
STILL SEEMS ON TARGET PER THE 18Z NAM GUIDANCE AS ANOTHER SHORT
WAVE RIDES NORTHEASTWARD. POPS WERE MAINTAINED FOR THIS.
HOWEVER...IN THE INTERIM BETWEEN NOW AND THEN...SKIES WERE REDUCED
FOR MOST AREAS TO BE GENERALLY PARTLY CLOUDY THROUGH THE BULK OF
THE EVENING AND EARLY OVERNIGHT PERIOD. FRIES

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
CONTINUED SOUTHWEST FLOW WILL MAINTAIN THE FUNNEL OF DEEP MOISTURE
OVER THE UPPER OHIO REGION...AT LEAST UNTIL THE ADVANCING MID LEVEL
TROUGH AXIS PROGRESSION SHUNTS THE PLUME EASTWARD BY THURSDAY AS
PER THE GFS AND NAM SOLUTIONS.

CHANCE...TO LIKELY SHOWER AND THUNDERSTORM WILL THUS BE MAINTAINED
FOR THE PERIOD. THE BEST OVERALL POPS AT MOMENT ARE STILL PROGGED
FOR WEDNESDAY...ALTHOUGH TODAYS MODEL RUNS ARE FASTER IN PUSHING
THE PARENT MID/UPR LEVEL TROUGH AXIS AND SUSTAINED MOISTURE TAP
EASTWARD...SO THOSE LIKELY NUMBERS WERE TRENDED SLIGHTLY EASTWARD
AS WELL.

THE SHORT TERM SEVERE POTENTIAL STILL LOOKS TO BE COMPROMISED BY
WARM MID LEVELS AND A MARGINAL DEEP LAYER SHEAR PROFILE...BUT WARM
RAIN PROCESSES AND TRAINING MAY SUPPORT LOCALLY HEAVY RAINFALL
UNTIL MOISTURE AND WARM CLOUD DEPTH WANES LATER ON WEDNESDAY.

NO MAJOR CHANGES WERE NEEDED FOR THE SEASONABLY WARM TEMP PROGNOSIS.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
PRECIP CHANCES WILL INCREASE AGAIN FOR THE WEEKEND...AND PERSIST
INTO NEXT WEEK AS MODELS AGREE ON A WEAK SPLIT FLOW REGIME
CONVERGING OVER THE GREAT LAKES/UPPER OHIO REGION. THE SURFACE
FRONT IS PROJECTED TO SAG SOUTHWARD UNTIL REDEVELOPING NORTHWARD
AS A WARM FRONT IN RESPONSE TO GREAT PLAINS TROUGHING EARLY NEXT
WEEK.

GIVEN MODEL MAGNITUDE...POSITIONING...AND TIMING DISPUTES...PERSISTENCE
WILL RULE THE LONG TERM FORECAST STRATEGY.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
GENLY VFR IS EXPECTED TO CONTINUE THROUGH TONIGHT AS THE ERODING
UPPER RIDGE OVER THE REGION SUPPRESSES CONVECTION.
HOWEVER...ISOLATED TO SCATTERED SHOWERS WILL INCREASE LOCAL
RESTRICTION POTENTIAL AND MOIST SOUTHERLY FLOW MAY SPAWN A
STRATUS/STRATOCU LAYER EARLY ON TUESDAY. SHOWERS COULD PRODUCE
MVFR RESTRICTIONS...AND POSSIBLY EVEN IFR CEILINGS IN HEAVIER
SHOWERS. TAFS THUS INCLUDE A VICINITY SHOWER MENTION AND A LATE
PERIOD...LOW END VFR CLOUD BASE FORECAST AS A LOW CONFIDENCE
HEDGE.

.OUTLOOK.../TUESDAY NIGHT THROUGH SATURDAY/...
ABUNDANT MOISTURE AND DISTURBANCES IN SOUTHWEST FLOW ARE LIKELY
TO SPAWN PERIODIC RESTRICTIONS THROUGH WEDNESDAY.

&&

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

&&

$$


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