Ice Storm in Pennsylvania, December 13 to 14, 2002

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
425 PM EST FRI DEC 13 2002

SPOTTERS REPORTING RAIN CHANGING TO HEAVY SNOW OVER MUCH OF SOUTHERN
PA. WILL ISSUE UPDATE...ADDING A COUPLE INCHES OF WET SNOW THIS
EVENING EVEN INTO THE LOWER SUSQ VALLEY.

FITZGERALD

********* PREV AFD FOLLOWS ***************

HERE WE GO AGAIN WITH ANOTHER COMPLEX WEATHER SYSTEM HEADED FOR
CENTRAL PA.  MODELS REMAIN DIVERGENT ENOUGH TO MAKE THIS A VERY
CHALLENGING FORECAST.  BEST SOLUTION INCORPORATES A BLEND OF
SHORT-TERM MODEL SOLUTIONS.

MIXED PRECIP MOVING INTO SOUTHERN PA AT THIS TIME WITH LOWER
ELEVATION SITES IN THE CENTRAL MOUNTAINS AND SE REPORTING PLAIN RAIN
AND HIGHER ELEVATIONS REPORTING SLEET AND FREEZING RAIN.  EXPECT A
MIX TO CONTINUE THROUGH THE EVENING AS PRECIP SPREADS INTO EVEN
COLDER SURFACE AIR FURTHER NORTH.

AS THE NIGHT PROGRESSES...WARMER AIR WILL FEED INTO CENTRAL PA
CHANGING MANY AREAS OVER TO PLAIN RAIN FOR SEVERAL HOURS.  PROBLEM
AREAS WILL CONTINUE TO BE THE HIGHEST ELEVATIONS AND ACROSS THE
NORTHERN MOUNTAINS WHERE COLDEST AIR IS STILL TRAPPED IN THE
VALLEYS.

BY SUNRISE SAT...CENTER OF UPPER LOW BEGINS TO MOVE ACROSS PA
COOLING THE ATMOSPHERE ENOUGH TO TURN PRECIP BACK TO THE FROZEN
VARIETY.  SCENARIO CONTINUES TO SUGGEST A SW-NE ORIENTED SNOWBAND TO
FORM IN THE NORTHWEST PORTION OF CWA.  SEVERAL INCHES OF SNOW WILL
FALL WHERE THIS BAND SETS UP.  WITH THIS IN MIND...AND COMBINED WITH
THE FREEZING RAIN TONIGHT...CONTINUED THE WARNINGS FOR THE W AND N
AND DECIDED TO CHANGE THE WATCH TO AN ADVISORY.

SYSTEM PULLS AWAY BY SAT EVE...BUT ANOTHER SHORTWAVE BRINGS A QUICK
SHOT OF LAKE-ENHANCED SNOW SHOWERS TO THE REGION SUNDAY.  AFTER
THAT...BASICALLY QUIET WEATHER UNTIL A WARMER WEATHER SYSTEM BEGINS
TO SPREAD A CHANCE OF RAIN INTO PA BY LATE WED/THU.

FCSTID =   16
MDT   34  41  31  44 / 100  70  10   0
IPT   34  38  30  41 / 100  90  20  10
BFD   28  31  25  33 / 100  90  30  30
JST   30  34  28  35 / 100  80  20  20
AOO   30  35  29  39 / 100  80  10  10
UNV   30  34  27  38 / 100  90  10  10
SEG   34  38  30  41 / 100  80  10  10
LNS   35  41  31  43 / 100  60  10   0
THV   34  41  31  43 / 100  60  10   0

.CTP...
PA...WINTER STORM WARNING FOR TONIGHT THROUGH SATURDAY AFTERNOON FOR
ZONES PAZ017...PAZ024...PAZ033.

WINTER STORM WARNING FOR TONIGHT THROUGH SATURDAY AFTERNOON FOR
ZONES PAZ004>006...PAZ010>011...PAZ037.

WINTER WEATHER ADVISORY FOR TONIGHT THROUGH SATURDAY AFTERNOON FOR
ZONES PAZ012...PAZ018>019...PAZ025>027...PAZ034...PAZ041>042...
PAZ045>046...PAZ049.

RXR

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-131330-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
601 AM EST FRI DEC 13 2002

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...TODAY

LOW PRESSURE OVER MISSISSIPPI EARLY THIS MORNING...WILL INTENSIFY AS
IT MOVES NORTHEAST ALONG THE APPALACHIAN MOUNTAINS TODAY AND
TONIGHT. A MIXTURE OF FREEZING RAIN AND SLEET WILL OVERSPREAD MOST
MOUNTAINOUS LOCATIONS OF STATE BY MID AFTERNOON.

SIGNIFICANT ICING MAY BEGIN ACROSS THE WESTERN AND NORTHERN
MOUNTAINS LATE TODAY.

THE PRECIPITATION WILL BE MAINLY RAIN ACROSS THE LOWER SUSQUEHANNA
VALLEY AND SOUTHEAST.

HEAVY ACCUMULATIONS OF ICE...GREATER THAN ONE QUARTER OF AN
INCH...MAY BRING DOWN TREE LIMBS AND POWER LINES ACROSS PORTIONS OF
THE WESTERN AND NORTHWEST MOUNTAINS TONIGHT BEFORE A CHANGEOVER TO
HEAVY WET SNOW OCCURS AFTER 3 OR 4 AM SATURDAY.

THE STORM WILL REFORM NEAR THE NEW JERSEY COAST ON SATURDAY. THIS
WILL ALLOW COLDER AIR TO MOVE INTO THE REGION VERY LATE
TONIGHT...LEADING TO A CHANGEOVER TO HEAVY WET SNOW ACROSS THE ALL
OF THE WESTERN AND CENTRAL MOUNTAINS.

TOTAL STORM SNOWFALL WILL LIKELY RANGE FROM AS MUCH AS 10 INCHES
ACROSS PARTS OF THE WESTERN AND NORTHERN MOUNTAINS. SNOW
ACCUMULATIONS BETWEEN 4 AND 7 INCHES ARE POSSIBLE FROM NEAR
ALTOONA...TO STATE COLLEGE AND WILLIAMSPORT BEGINNING DURING THE PRE
DAWN HOURS OF SATURDAY.

2 TO 3 INCHES OF SNOW IS POSSIBLE BY LATE SATURDAY ACROSS THE EAST
CENTRAL MOUNTAINS OF THE STATE...NEAR TAMAQUA AND POTTSVILLE.

.DAYS TWO THROUGH SEVEN...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE LIKELY BEGINNING LATE THIS AFTERNOON.
PLEASE REPORT ANY SIGNIFICANT ACCUMULATION OF ICE...OR DOWNED TREES
RESULTING IN POWER OUTAGES.

LATER IN THE UPCOMING STORM...PLEASE REPORT SNOWFALL RATES OF 1 INCH
OR MORE PER HOUR...EVERY 3 INCHES OF SNOWFALL...AND TOTAL STORM SNOW
ACCUMULATION.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

LAMBERT