Ice Storm in Pennsylvania, April 7, 2003

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
833 PM EDT SUN APR 6 2003

UPDATE THIS EVENING WL BE MAINLY TO REFINE THE SNOW AMOUNTS WHILE
KEEPING ALL WARNING AND ADVSRYS IN PLACE AS IS. NEWER MDL GUID AND
RADAR MOSAIC TRENDS SUGGS THE PLACEMENT OF HEAVIER SNOWS WL BE MORE
IN CENTRAL MTNS (MAINLY A STRIPE FM JST-UNV-IPT) AND MID SUSQ. LWRD
AMTS IN NRN MTNS...BUT STILL ABV SNOW WARNING CRIT (5-8 INCHES).

MINIMAL  FOR TOO MUCH MIXING WITH SLEET AND FZRA TO GET TO WARNING
CRIT IN LWR SUSQ. BUT...FEEL WARNING CONTS TO BE WARRANTED DUE TO
THE MAGNITUDE/TIMING OF THE SNOW AND THE POSSIBILITY OF SIGNIFICANT
ICING TO OCCUR. WL UPD THE WORDING ON THE WSW...BUT MOST OF THE
TIMING REMAIN SIMILAR. MORNING RUSH HRS UNTIL EARLY AFTN.

NEW GRIDS AVBL...RDF/ZFP BY 930 PM.

.CTP...
PA...WINTER STORM WARNING ALL COUNTIES EXCEPT ADAMS...YORK AND
LANCASTER...WHERE WINTER WEATHER ADVISORY IS POSTED FOR LATE TONIGHT
INTO MON.

DANGELO

EARLIER DISC FOLLOWS:

...MAJOR WINTER STORM HEADED FOR THE REGION...

AS OF 19Z...CLOUDS RAPIDLY THICKENING ACROSS CWA FROM WSW->ENE.
VIRGA SHOWING UP ON ILN RADAR...BUT WEAKENING AS IT HEADS INTO DRIER
AIR TO THE N/E. TEMPS RANGING FROM L/M 30S FAR NW...TO M/U 40S FAR
SE. DEWPTS RUNNING A BIT HIGHER THAN FWC/MAV NUMBERS
PROJECTED...GENERALLY NR/ABOVE 20 LOWER SUSQ...AND UPPER TEENS
ELSEWHERE.

TNT...SNOW MOVES INTO REGION AROUND MIDNIGHT LAURELS...SHORTLY AFTER
MIDNIGHT S/W OF KUNV...THEN CLOSER TO DAYBREAK KIPT N AND E. BY
12Z...EXPECT AN INCH OR LESS SUSQ VALLEY (INCLUDING LOWER
SUSQ)...1-2 INCHES CENTRAL AREAS...AND AROUND 2 INCHES IN LAURELS.

MON...PERIOD OF STEADY/HEAVY SNOW ACROSS CWA THROUGH THE AM...THEN
DECREASING IN INTENSITY DURING THE AFTN. COULD EASILY HAVE 1-2 IN/HR
IN AREAS DURING THE AM. AM COMMUTE LIKELY TO BE ADVERSELY IMPACTED.
SOME SLEET TO MIX IN ACROSS LOWER SUSQ...AND S/E OF A KJST-KAOO
LINE. AS VORT SWINGS TO OUR NE MID-LATE AM...THE SNOW/SLEET WILL
DECREASE IN INTENSITY AND BECOME MORE SPOTTY FROM SW->NE THROUGH THE
AFTN. COULD BE SOME FREEZING DRIZZLE LINGERING...BUT WITH THICKNESS
OF CLOUDS DECREASING A BIT...INSOLATION MAY BE ENOUGH TO START
MELTING PROCESS ON SOME ROADWAYS DURING THE AFTN HOURS...EVEN
W/TEMPS HOVERING NEAR FREEZING. FOR ACCUMS...EXPECT 5 TO 8 INCHES
ACROSS A LARGE PORTION OF CENTRAL PA...WITH 8 TO 12 INCHES POSSIBLE
ACROSS HIGHER ELEVS. OF NORTH CENTRAL PA. 4-6 INCHES EXPECTED NEAR
HARRISBURG...2 TO 4 INCHES ACROSS EXTREME LOWER SUSQ WHERE
SLEET/FREEZING RAIN MIXES IN. ALSO...FOR LAURELS...EXPECT 4 TO 6 IN
OF SNOW...FOLLOWED BY ICE ACCRETION OF UP TO 0.30 INCHES. WITH
WEIGHT OF WET SNOW/ICE...COMBINED WITH BUDDING FOLIAGE...COULD
EASILY BE SOME DOWNED TREES/POWERLINES ACROSS THE HIGHER ELEVS. OF
LAURELS...AND OTHER PORTIONS OF CENTRAL PA.

MON NT...LINGERING LOW LEVEL MOISTURE WITH LT SNOW/FREEZING DRIZZLE.
LITTLE IN THE WAY OF ADDITIONAL QPF...BUT STILL SOME MINOR ICE
ACCRETIONS POSSIBLE ON TREES...ESP HIGHER ELEVS.

TUE/TUE NT...ETA PROGS ANOTHER IMPULSE TO MOVE NE AHEAD OF
SHARPENING MID LEVEL TROUGH TO OUR W. GFS WEAKER...AND FURTHER S/E
WITH FEATURE. FOR NOW...BELIEVE THAT ABUNDANT LOW LEVEL
MOISTURE...COMBINED WITH WEAK DYNAMICS SHOULD BE SUFFICIENT TO
CONTINUE POPS FOR RAIN/SNOW SHOWERS INTO TUE NT. IF ETA VERIFIES...A
PORTION OF CWA (MAINLY CENTRAL AND N) COULD HAVE ADDITIONAL SNOW/ICE
ACCUMS TUE NT.

WED AND BEYOND...LINGERING RW/SW EARLY WED...OTRW CLEARING AND
MILDER TEMPS. SE COASTAL SYSTEM STILL QUESTIONABLE...BUT AT THIS
PT...FEEL THAT AT LEAST SE PORTION OF CWA COULD GET SOME LT RAIN
SOMETIME FRI. IMPROVING CONDITIONS...ALBEIT A BIT COOLER THAN
NORMAL...FOR NEXT WEEKEND.

KL

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-070700-

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE STATE COLLEGE PA
700 PM EDT SUN APR 6 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...TODAY

SNOW WILL OVERSPREAD THE REGION FROM SOUTHWEST TO NORTHEAST LATE
THIS EVENING THROUGH SUNRISE MONDAY MORNING. SNOW WILL FALL HEAVILY
AT TIMES MONDAY MORNING...INTO EARLY AFTERNOON. THE SNOW WILL MIX
WITH OR CHANGE TO SLEET AND FREEZING RAIN OVER THE LAUREL HIGHLANDS
AND EXTREME LOWER SUSQUEHANNA VALLEY (SOUTH OF HARRISBURG).
ACCUMULATIONS WILL BE 5 TO 6 INCHES OR MORE FOR MOST OF THE
REGION...WITH UP TO A FOOT POSSIBLE ACROSS THE NORTHERN MOUNTAINS.

WINTER STORM WARNINGS AND ADVISORIES HAVE BEEN POSTED FOR ALL OF
CENTRAL PENNSYLVANIA. REFER TO THE WARNINGS (WWUS41 KCTP WSWCTP) AND
LOCAL FORECASTS (FPUS51 KCTP ZFPCTP) FOR MORE SPECIFIC INFORMATION.

.DAYS TWO THROUGH SEVEN...

THE SNOW AND ICE WILL TAPER TO FREEZING DRIZZLE AND LIGHT SNOW
MONDAY EVENING AND LINGER THROUGH TUESDAY MORNING. ADDITIONAL LIGHT
ACCUMULATIONS ARE POSSIBLE BUT NOT LIKELY MONDAY NIGHT AND TUESDAY.

NO FURTHER HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE LIKELY.
SPOTTERS...PLEASE REPORT SNOWFALL GREATER THAN AN INCH PER HOUR...OR
WHEN YOU REACH THESE LEVELS:
3 INCHES...
6 INCHES...
12 INCHES.
ALSO REPORT ANY ICE ACCRETION OF GREATER THAN A TENTH OF AN INCH.

DANGELO