Flood in Pennsylvania, March 7, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
344 AM EST SUN MAR 7 2004

.DISCUSSION...
TRANSITION TO COOLER NORTHWEST FLOW REGIME THIS WEEK CONTS TO TAKE
PLACE TODAY WITH FIRST IN SERIES OF CLIPPER SYSTEMS USHERING IN
COLDER AIR ALOFT...AND REINTRODUCING SNOW TO THE FORECAST.  ETA/GFS
SIMILAR IN BRINGING PRECIPITATION SHIELD INTO THIS FORECAST AREA
MAINLY AFTER 18 UTC...SO WENT WITH CAT POPS NORTHERN/WESTERN
SECTIONS TODAY WITH LIKELIES TO THE EAST. WITH RELATIVELY WARM
BOUNDARY LAYER CONDITIONS TO START...SHOULD SEE A MIXTURE OF RAIN
AND SNOW ACROSS THE MOUNTAINS AND PLAIN RAIN OVER THE MID TO LOWER
SUSQ.  SOME SLUSHY ACCUMS UP TO AN INCH ARE POSSIBLE MAINLY ON THE
RIDGES OVER WESTERN AND NORTHERN PA BY LATE AFTERNOON.

QPF IN THE .25 TO .4 INCH RANGE SUPPORTS A LIGHT SNOWFALL OVER THE
WESTERN AND NORTHERN MOUNTAINS THIS AFTERNOON THROUGH LATE TONIGHT.
GENERALLY GOING WITH TOTAL ACCUMS IN THE 1 TO 3 INCH RANGE...WITH
LESSER AMOUNTS TOWARDS THE CENTRAL AND SOUTH CENTRAL MOUNTAINS.  AIR
MASS DESTABLIZES THIS AFTERNOON WITH SFC BASED CAPES INCREASING TO
200 TO 400 J/KG2 AND LIS BELOW ZERO TOWARDS LATE AFTERNOON - MIGHT
SUPPORT A FEW HEAVIER SNOW BURSTS OR GRAUPEL SHOWERS.

MAIN PRECIP SHIELF ADVANCES OFF TO THE EAST TONIGHT WITH COLD AND
UNSTABLE BOUNDARY LAYER CONDS IN LARGE SCALE NORTHWEST FLOW KEEPING
SNOW SHOWER AND FLURRY CHANCES GOING OVERNIGHT AND MONDAY.

NEXT CLIPPER SYSTEM DIGS MUCH FURTHER SOUTH THAN THE CURRENT ONE ON
TUESDAY...AS UPPER TROF CARVES OUT WELL SOUTH TO THE CAROLINAS.
STILL MAY SEE SOME FLURRIES OR LIGHT SNOW SHOWERS AFFECT PORTIONS OF
OUR AREA...BUT MAIN DYNAMICS LOOK TO DROP WELL SOUTH AS 850 TEMPS
DIP TO -10 OVR N CENTRAL PA.  SOME MODERATION STILL SEEN IN THE LATE
WED TO EARLY THU TIMEFRAME AHEAD OF A SHEARING COLD FRONT DUE TO
ARRIVE THU AFTERNOON WITH ANOTHER BRIEF PUNCH OF COLD AIR AT THAT
TIME.  MODERATION STILL SEEN BEYOND IN DAYS 7 AND 8 WITH BROAD
SOUTHWEST FLOW ALOFT RETURNING...AND POTENTIAL STORMINESS RETURNING
NEXT MONDAY.

&&

.HYDROLOGY...
MINOR FLOODING IS OCCURRING FOR THE WEST BRANCH SUSQUEHANNA AT
MONTGOMERY AND IS FORECAST TO CONTINUE THROUGH THIS AFTERNOON.
THE LATEST STAGE REPORTED BY THE EMERGENCY MANAGEMENT COORDINATOR
WAS ESTIMATED AT 16.7 FEET AROUND MIDNIGHT. THE MAXIMUM STAGE
FORECASTED IS AROUND 17.5 FEET SUNDAY AFTERNOON. ALL OTHER POINTS
WILL CREST AT OR BELOW CAUTION STAGE.

&&

.PRELIMINARY POINT TEMPS/POPS...
HARRISBURG     50  34  45  27 /  40  60  20  10
WILLIAMSPORT   43  32  41  25 /  70  70  40  10
BRADFORD       36  23  31  17 /  90  70  30  20
JOHNSTOWN      38  25  33  22 /  60  60  30  20
ALTOONA        43  30  38  25 /  60  60  20  10
STATE COLLEGE  41  30  38  25 /  70  70  20  10
SELINSGROVE    46  32  41  25 /  50  70  30  10
LANCASTER      50  33  45  28 /  40  60  20  10
YORK           50  33  45  28 /  40  60  20  10
&&

.CTP WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
&&

DEVOIR

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE STATE COLLEGE PA
455 AM EST SUN MAR 7 2004

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-071155-
ADAMS PA-BEDFORD PA-BLAIR PA-CAMBRIA PA-CAMERON PA-CLEARFIELD PA-
COLUMBIA PA-CUMBERLAND PA-DAUPHIN PA-ELK PA-FRANKLIN PA-FULTON PA-
HUNTINGDON PA-JUNIATA PA-LANCASTER PA-LEBANON PA-MCKEAN PA-
MIFFLIN PA-MONTOUR PA-NORTHERN CENTRE PA-NORTHERN CLINTON PA-
NORTHERN LYCOMING PA-NORTHUMBERLAND PA-PERRY PA-POTTER PA-
SCHUYLKILL PA-SNYDER PA-SOMERSET PA-SOUTHERN CENTRE PA-
SOUTHERN CLINTON PA-SOUTHERN LYCOMING PA-SULLIVAN PA-TIOGA PA-
UNION PA-WARREN PA-YORK PA-
455 AM EST SUN MAR 7 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL PENNSYLVANIA.

.DAY ONE...TODAY:

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY:

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER CALL TO ACTION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.