Heavy Snow in Pennsylvania, February 5, 2001

AREA FORECAST DISCUSSION...CORRECTED WATCH/WARNING PORTION AT BOTTOM
NATIONAL WEATHER SERVICE STATE COLLEGE PA
836 PM EST SUN FEB 4 2001

WILL RIDE WITH THE CURRENT CONFIGURATION OF THE WINTER WEATHER
ADVISORY FOR LATE TNGT AND MONDAY MORNING FOR THE EXTREME SOUTHEAST
ZONES OF OUR CWFA AND ECENT MTNS. PERHAPS THE ONLY CHANGE WITH
RESPECT TO THIS ADVIS WILL BE TO TWEAK THE WORDING FOR THE INITIAL
SNOWFALL IN ORDER TO LEAN MORE TWD A LATER ONSET AND ENDING TIME OF
THE SIGNIF PRECIP.

WE SHOULD SEE SOME RAPID DEVELOPMENT CONCERNING SFC LOW PRESSURE
STRENGTHENING AND THE SUBSEQUENT BLOSSOMING OF RAIN ACROSS THE SE
AND CAROLINAS DURING THE NEXT SEVERAL HOURS AS A STRONG UPR JET MAX
(110 KT AT 400 MB) DIVES SE TO CENTRAL GEORGIA AT 08Z. THIS FEATURE
WAS IN NCENT MISS AT 01Z...AND MVG TO THE ESE AT AROUND 40 KTS.

I EXPECT TO SEE DEEP UVVEL DVLP AND PRECIP BEGINNING TO ADVECT IN A
MORE NWD DIRECTION THROUGH THE CAROLINAS AND INTO CENT/NRN VIRGINIA
AFTER MIDNIGHT...AS THE UPPER TROUGH BEGINS TO TAKE ON A SLIGHTLY
NEG TILT RESULTING IN STG UPPER DIVERGENCE AND STEADY SFC LOW
DEVELOPMENT JUST EAST OF KILM.

VERY SIMILAR SITUATION WITH RESPECT TO STORM TRACK (THROUGH A
SOMEWHAT WARMER BLYR) AS WE EXPERIENCED BACK ON DEC 30, 2000.
WHAT WAS LACKING BACK THEN WAS AN ALREADY AMPLIFIED TROUGH AND SW
FLOW ACROSS THE APPALACHIANS...WHICH THIS TIME WILL PROMOTE EARLIER
(MORE SOUTHWARD SFC LOW DEVELOPMENT)...PERHAPS LEADING TO A BIT MORE
WESTERLY EXTENSION OF THE SIGNIF QPF IN OUR ZONES. THE SFC LOW IN
THAT CASE DEVELOPED QUICKER/AND A FEW HUNDRED KM NORTH OF THE
MODEL'S INITIAL LOCATION OFF CAPE HATTERAS.

ALSO RECALL THAT ON DEC 30TH...THE INITIAL AREA OF STRONG UVVEL AND
THE TIGHT WESTERN QPF GRADIENT ONLY BRUSHED SCHUYLKILL COUNTY IN
ECENT PENN DURING THE MORNING HOURS. EVENTUALLY ADVISORY CRITERIA
SNOW DID ADVECT WSW INTO SULLIVAN AND COLUMBIA COUNTY LATER THAT
EVENING AS THE TROUGH DEEPENED AFTER UPR ENERGY JUMPED THE
APPALACHIANS.

ETA...MESO ETA...NGM AND LOCAL MM5 ALL SHOW A GENERAL N/S PRECIP
AXIS...WHILE THE AVN IS ORIENTED MORE SW/NE. ETA/REGIONAL SPECTRAL
MODEL (MULTI MODEL) ENSEMBLE QPF IS A COMPROMISE OF THE ABOVE...WITH
THE 0.5" 24-HOUR QPF LINE ENDING 00Z TUES EXTENDING FROM JUST WEST
OF KLNS TO KAVP. SURROUNDING THIS CONTOUR...AS EXPECTED...IS A
RATHER HIGH DEGREE (>0.25") OF VARIABILITY FROM THE INDIVIDUAL
ENSEMBLE MEMBERS...SUGGESTING THAT WE COULD STAND TO PLAY THIS STORM
THE WAY WE CURRENTLY HAVE IT (FOR NOW) WITH THE ADVISORY FOR 4-5" IN
OUR EXTREME EAST...AND A SPECIAL STATEMENT FOR LESSER AMOUNTS OF
"WET" SNOW ACROSS THE SUSQ VALLEY. 18Z MESO ETA IS THE MOST OMINOUS
IN THE QPF DEPT...PAINTING AOA ONE-INCH AMOUNTS ACROSS ERN
LANCASTER...LEBANON AND SCHUYLKILL COUNTIES.

IF THE INITIAL SWATH OF PRECIP WELL AFTER MIDNIGHT TAKES AIM MORE
TWD THE HARRISBURG/YORK VICINITY...THE MID SHIFT CREW MAY HAVE TO
ADJUST AMOUNTS UPWARD FOR A LAYER OR TWO OF COUNTIES FURTHER NORTH
AND WEST OF THE CURRENT ADVIS AREA...AND PERHAPS UPGRADE TO A WINT
STM WARNING ACROSS THE ADVIS AREA.

FCST MINS OVERNIGHT LOOK ON TRACK. WILL MODIFY WINDS A BIT AND WORD
SNOW MORE ON THE INTERMITTENT AND LIGHT SIDE ACROSS THE CENTRAL AND
NE COUNTIES.

.CTP...WINTER WEATHER ADVISORY FROM LATE TONIGHT INTO MONDAY AFTERNOON
       FOR PAZ058-059-065-066 OF TmHE LWR SUSQ VALLEY AND ECENT MTNS.

       SPS FOR POTENTIAL SIGNIF (>3 INCHES) SNOW ACCUMULATIONS
       FOR THE CENTRAL SUSQ VALLEY...AND PARTS OF NCENT PENN.

LAMBERT

PAZ028-036-037-041-042-046-049>053-056-057-063-064-051100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1050 PM EST SUN FEB 4 2001

...SEVERAL INCHES OF WET SNOW POSSIBLE ON MONDAY...

LOW PRESSURE DEVELOPING OFF THE SOUTH CAROLINA COAST WILL MOVE
GRADUALLY NORTH TO A POSITION SOUTHEAST OF NEW YORK CITY MONDAY
AFTERNOON. THIS STORM WILL BRING HEAVY...WET SNOW WITH ACCUMULATIONS
IN EXCESS OF 6 INCHES BY LATE MONDAY ACROSS MUCH OF THE LEHIGH VALLEY
AND POCONO MOUNTAINS OF EASTERN PENNSYLVANIA.

SNOW SHOWERS...AND PERHAPS PERIODS OF STEADIER WET SNOW WILL OCCUR
ACROSS OUR REGION FROM THE PREDAWN HOURS MONDAY...INTO MONDAY
AFTERNOON.

SINCE THE TEMPERATURE NEAR THE GROUND IS EXPECTED TO BE WITHIN A
FEW DEGREES OF FREEZING...THE SNOW WILL BE SLOWER TO ACCUMULATE IN
COMPARISON TO A MORE TYPICAL WINTER STORM.

TOTAL SNOWFALL AMOUNTS OF 1 TO 3 INCHES ARE LIKELY BY LATE MONDAY
THROUGHOUT THE CENTRAL SUSQUEHANNA VALLEY AND ADJACENT CENTRAL
MOUNTAIN REGION. LOCALLY HIGHER AMOUNTS ARE POSSIBLE AT ELEVATIONS
ABOVE 1000 FEET.

THE BULK OF THE SNOW ACCUMULATION WILL OCCUR ON COLDER SURFACES SUCH
AS GRASS...AND POSSIBLY BRIDGES AND OVERPASSES. MOST HIGHWAYS AND
TREATED SECONDARY ROADS WILL REMAIN WET...SO SIGNIFICANT TRAVEL
PROBLEMS ARE NOT EXPECTED ACROSS MUCH OF THE SUSQUEHANNA AND
REMAINDER OF CENTRAL PENNSYLVANIA.

THE EXCEPTION TO THIS WOULD BE IF A VSLIGHTLY MORE WESTWARD STORM
TRACK BROUGHT HEAVIER SNOWFALL RATES AND ACCUMULATIONS TO THE AREA
ON MONDAY.

LAMBERT