Area Forecast Discussion
Issued by NWS

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FXUS61 KPBZ 260203 AAB
AFDPBZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
903 PM EST WED FEB 25 2015

.SYNOPSIS...
LIGHT SNOW SHOWERS THURSDAY WILL GIVE WAY TO DRY AND FRIGID
CONDITIONS FRIDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
9 PM UPDATE...NO REAL CHANGES FROM PREVIOUS UPDATE. JUST MADE SOME
MINOR CHANGES TO POPS LATE TONIGHT AND UPDATED TEMPS TO LATEST
GUIDANCE. REST IN GOOD SHAPE.

PREVIOUS DISCUSSION...

COLD ADVECTION AT 850MB TONIGHT WHILE WINDS ALOFT BECOME
SOUTHWESTERLY AND MID LEVEL MOISTURE INCREASES. NORTHERN STREAM
SYSTEM APPROACHES FROM THE WEST...WHILE A UPPER LEVEL DISTURBANCE
MOVES NORTHEAST TO THE MID ATLANTIC STATES. THIS PUTS THE BULK OF
THE REGION IN BETWEEN SYSTEMS WITH LIMITED DEEP MOISTURE. LIGHT
SNOW SHOWERS WILL SPREAD TOWARD THE RIDGES BEFORE DAYBREAK FROM
THE SOUTHERN SYSTEM...WHILE SNOW SHOWERS WITH NORTHERN STREAM WAVE
WILL MOVE IN FROM THE WEST. AN INCH OR SO FOR THE HIGHER RIDGES AND
LESS THAN AN INCH NEAR THE I-80 CORRIDOR. TEMPERATURES WILL BE A
BIT TRICKY WITH CLOUD COVER FIGHTING THE COLD ADVECTION
OVERNIGHT...SINGLE DIGITS FAR NORTH TO UPPER TEENS FAR SOUTH.
TEMPERATURES WILL STRUGGLE INTO THE TEENS AND 20S THURSDAY.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
SNOW SHOWERS WILL BE DIMINISHING WEST TO EAST THURSDAY EVENING
WITH 850MB TEMPS RANGING FROM -18 TO -20C BY 12Z FRIDAY BASED ON
THE NAM. THIS WILL PUSH TEMPERATURES INTO THE SINGLE DIGITS WITH
BELOW ZERO READING ACROSS THE NORTH. ARCTIC HIGH WILL BUILD OVER
REGION FOR FRIDAY THROUGH SATURDAY KEEPING TEMPERATURE 25 TO 30
DEGREES BELOW AVERAGE. CLEAR SKIES FRIDAY NIGHT WITH CALM WINDS
OVER SNOW WILL ALLOW FOR TEMPERATURES WELL BELOW ZERO FRIDAY NIGHT.
SURFACE RIDGE AXIS BEGINS TO PUSH EAST SATURDAY AFTERNOON
ALLOWING TEMPERATURES TO RECOVER INTO THE 20S WITH NEAR 30 FOR
THE MASON DIXON LINE.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MINIMAL CHANGES TO THE EXTENDED WERE MADE MAINLY FOR COORDINATION
WITH SURROUNDING OFFICES.

MARCH BEGINS WITH SFC HIGH PRESSURE BEING SHUNTED TO OUR EAST AS A
LONGWAVE TROF DIGS IN ALONG THE PACIFIC COAST. THIS WILL AT LEAST
TEMPORARILY BRING A CHANGE TO THE UPPER LEVEL FLOW TO A MORE ZONAL
REGIME. A WEST TO EAST BOUNDARY WILL SERVE AS A LOOSE FOCUS FOR
PRECIPITATION OVERSPREADING THE REGION BY LATE WEEKEND.
TEMPERATURES SUNDAY SHOULD MOVE TOWARD THE SEASONAL AVERAGE...WHICH
WILL PROVIDE A MIX OF PRECIPITATION TYPES. GIVEN THE RECENT COLD
TEMPERATURES...SFC TEMPERATURES MAY RESULT IN FREEZING RAIN BEING
INCLUDED IN FUTURE UPDATES. AT THE MOMENT...INCLUSION OF A FEW
HOURS OF FREEZING RAIN IS A BIT TOO FINE SCALE AND THUS CONFIDENCE
IS NOT HIGH ENOUGH.

LONG RANGE GUIDANCE VARIES A BIT HEADING INTO NEXT WEEK...BUT SIGNS
POINT TO ANOTHER STORM SYSTEM FROM THE SOUTHERN STREAM MOVING EAST
MID WEEK WITH ANOTHER ROUND OF MIXED PRECIPITATION.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WITH GENERALLY LIGHT NE WINDS WILL CONTINUE AS HIGH
CLOUDS ROLL INTO THE AREA AND SLOWLY LOWER THROUGH THE EVENING AND
EARLY OVERNIGHT. A LOW PRESSURE SYSTEM MOVING ACROSS THE SOUTHERN
STATES OVERNIGHT INTO TUESDAY WILL GENERALLY MOVE TO THE SOUTHEAST
OF THE AREA...HOWEVER ADDITIONAL LOWERING OF THE CLOUDS IS LIKELY
WITH THIS SYSTEM BY EARLY THURSDAY. WHILE THE HEAVIEST
PRECIPITATION WITH THIS SYSTEM WILL STAY SOUTH...A DIGGING UPPER
TROUGH OVER THE GREAT LAKES WILL PULL SOME MOISTURE IN FROM THIS
SYSTEM. THIS SHOULD BRING A PERIOD OF MVFR CIGS AND VSBYS IN SNOW
ACROSS MOST OF THE TAF SITES BY TOMORROW MORNING...WITH PERIODIC IFR
VISIBILITY POSSIBLE. FOR NOW...OPTED TO TREND TO MVFR CONDITIONS
BY TOMORROW MORNING...LEAVING PREVAILING IFR OUT.

OUTLOOK.../THURSDAY NIGHT THROUGH MONDAY/...
RESTRICTIONS MAY LINGER INTO FRIDAY BEFORE HIGH PRESSURE BRINGS
VFR CONDITIONS FOR MUCH OF THE WEEKEND. RESTRICTION POSSIBILITIES
WILL RETURN LATE SUNDAY/MONDAY WITH AN APPROACHING COLD FRONT.

&&

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

&&

$$





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