Area Forecast Discussion
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084
FXUS61 KPBZ 070305
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1005 PM EST SAT FEB 6 2016

.SYNOPSIS...
WARM TEMPERATURES ARE EXPECTED SUNDAY. HOWEVER...LOW PRESSURE
WILL SPREAD RAIN AND SNOW OVER THE REGION ON MONDAY AND TUESDAY.

&&

.NEAR TERM /THROUGH SUNDAY/...
WHAT HIGH DECK THERE WAS HAS DEPARTED TO THE SOUTHEAST AHEAD OF
THE PASSING UPPER SHORTWAVE TROUGH. WEAK WARM ADVECTION WILL
CONTINUE IN THE TROUGHS WAKE...WITH SURFACE RIDGING REMAINING
DOMINANT OVERNIGHT THROUGH SUNDAY. THUS...ONLY MINOR ADJUSTMENTS
WERE MADE TO THE FORECAST TONIGHT...WITH THE MOST NOTABLE CHANGE
MADE TO DEWPOINTS AS MID TEEN VALUES CONTINUE TO REMAIN PRESENT.
MODEL GUIDANCE SUPPORTS INCREASING VALUES...BUT NOT TO THE DEGREE
AT WHICH THEY WERE FORECAST. SINCE WE WILL LIKELY
DECOUPLE...TEMPERATURES SIMILAR TO LAST NIGHTS VALUES ARE
FORECAST.

WE WILL REMAIN IN THE RIDGING BETWEEN TWO LOW PRESSURE
SYSTEMS...OVER THE UPPER MISSISSIPPI VALLEY AND SOUTHEASTERN
U.S...ON SUNDAY. TEMPERATURES WILL REMAIN SLIGHTLY ABOVE SEASONAL
AVERAGES.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
THE UPR MS LOW IS CURRENTLY FORECAST TO DEEPEN OVR THE GREAT LAKES
AND MIDWEST...HENCE AMPLIFYING THE SOUTHWEST...TO SOUTHERLY FLOW
OVR THE UPR OH FOR SUNDAY NIGHT AND MONDAY. IMPROVED MOISTURE AND
ASCENT FIELDS WILL THUS SUPPORT INCREASED PRECIP PROBS OVER
WESTERN ZONES ON SUNDAY NIGHT WITH EASTWARD ENHANCEMENT ON
MONDAY.

THE MARGINAL TEMP PROFILE AND WARM BOUNDARY LAYER IN THE WARM
ADVECTION REGIME ON THE EASTERN FLANK OF THAT SYSTEM ARE LIKELY TO
COMPROMISE SNOW POTENTIAL AND PRECLUDE SERIOUS ACCUMULATION
THROUGH MONDAY...HOWEVER...THE SYSTEMS FRONTAL PASSAGE WILL
DECISIVELY CHANGE THE TEMP PROFILE AS NIGHT FALLS ACCORDING TO
CURRENT TIMING.

FORTUNATELY...THE ENCROACHMENT OF THE MID/UPR LOW CENTER SHOULD
SUFFICIENTLY WEAKEN THE WIND/FRONTOGENESIS POTENTIAL AND OVERALL
ASCENT FIELDS AND THUS OFFSET THE IMPROVED TEMP PROFILE FOR SNOW.
THE FORECAST IS THUS OF PROLONGED SNOW SHOWER POTENTIAL THROUGH
TUESDAY WITH RELATIVELY MINOR ACCUMULATION GIVEN THE TIME FRAME.
THE EXCEPTION LOOKS TO BE THE RIDGES AS USUAL WHERE OROGRAPHIC
SUPPORT SHOULD SUPPORT MORE SIGNIFICANT ACCUMULATION. A MENTION IN
THE HAZARDOUS WEATHER OUTLOOK WAS INCLUDED FOR THAT POTENTIAL.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE AFOREMENTIONED LOW IS GFS/ECMWF FORECAST TO CUTOFF AND
DEVELOP EASTWARD BEFORE FILLING/PHASING INTO THE LONGWAVE PATTERN
BY MIDWEEK. NEVERTHELESS...OVERALL UPPER TROUGHING IS PROGGED OVR
THE GREAT LAKES/UPR OHIO REGION FOR THE LONG-TERM PERIOD...WITH
AMPLIFICATION INDICATED TOWARD THE WEEKEND. SUB-AVG TEMPS AND
PERSISTENT SNOW SHOWER CHANCES WERE MAINTAINED FOR THE PERIOD...WITH
FOCUS TOWARD THE I-80 CORRIDOR AND RIDGES DURING THE LATTER HALF
OF THE WEEK.

THE LONG TERM WAS CONSTRUCTED USING THE SUPERBLEND GUIDANCE.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WILL CONTINUE THROUGH THE NIGHT AND INTO SATURDAY.
LIGHT SOUTHWESTERLY FLOW WILL TURN MORE SOUTHERLY ON
SATURDAY...WITH A FEW GUSTS POSSIBLE BY AFTERNOON. FRIES

.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
RESTRICTIONS ARE LIKELY SUNDAY NIGHT INTO MONDAY WITH A PASSING
SYSTEM. NORTHWESTERLY FLOW WILL CONTINUE THROUGH MOST OF NEXT
WEEK...MEANING STRATUS AND SNOW SHOWERS WILL CONTINUE SOME
RESTRICTIONS THROUGH MUCH OF THE WEEK.

&&

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

&&

$$



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