FXUS61 KCTP 220707
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
207 AM EST TUE DEC 22 2009

.SYNOPSIS...
AN UPPER LEVEL LOW WILL PASS TO THE NORTH OF THE STATE TODAY AND
WEDNESDAY. THIS LOW PRESSURE WILL KEEP THE REGION UNSEASONABLY
COLD THROUGH MID-WEEK WITH CLOUDS AND FLURRIES ACROSS THE NORTH
AND WEST. A STRONG LOW PRESSURE SYSTEM OVER THE MIDWEST WILL
LIKELY PRODUCE SOME WINTRY PRECIPITATION CHRISTMAS EVE...BUT IT
MAY TURN TO A COLD RAIN ON CHRISTMAS DAY.

&&

.NEAR TERM /THROUGH TODAY/...
CLOUDS SOLID OVER THE ENTIRE AREA EARLY THIS MORNING...BUT THE
FLOW BECOMES LESS CYCLONIC BY LATE IN THE DAY. UNTIL THEN...THE
SNOW SHOWERS AND FLURRIES DOWN WIND OF THE LAKE WILL CONTINUE.
HOWEVER...THE RELATIVELY HIGH BASES TO THE CLOUDS WILL KEEP MOST
AREAS FROM GETTING ANY ACCUMULATING SNOW. JUST A DUSTING IS
POSSIBLE THROUGH 10 AM. BREAKS WILL APPEAR IN THE CLOUDS...MAINLY
IN THE SOUTHEAST ON THE DOWNSLOPE. TEMPS MAY NOT CLIMB MORE THAN
6 OR 8F THRU THE DAY...DUE TO 8H TEMPS DROPPING SLIGHTLY AND THE
PERSISTENT CLOUD DECK.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
LOWERING INVERSION FINALLY GETS NEAR THE SFC...THERMAL TROF
PASSES TO THE EAST AND LLVL FLOW BECOMES DIFFLUENT AS HIGH
PRESSURE BEGINS TO BUILD IN THIS EVENING. THIS WILL HELP TO BREAK
UP THE LOW CLOUDS...EXCEPT IN THE FAR NORTH WHERE THE BREAKS MAY
ONLY BE BRIEF. THE FLOW IS STILL NORTHERLY AND COULD BRING
ADDITIONAL/RENEWED CLOUDS IN FM LK ONT. EXPECT SOME SINGLE DIGIT
READINGS ACROSS THE AREA WITH SNOWPACK ON GROUND. WITH SUCH A
CHILLY START...TEMPS MAY NOT GET BACK UP TO FREEZING ANYWHERE IN
THE CWFA WED. 

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
A WINTRY MIX POSSIBLE FOR CHRISTMAS EVE...

CONFIDENCE REMAINS HIGH WITH REGARDS TO A PERIOD OF WINTRY
PRECIPITATION AFFECTING CENTRAL PENN LATE CHRISTMAS EVE...WITH A
HIGH PROBABILITY OF A CHANGE TO PLAIN RAIN ON CHRISTMAS DAY. THIS
WILL UNDOUBTEDLY HAVE NEGATIVE IMPACTS ON HOLIDAY TRAVEL. TIMING
OF THE ONSET AND HEAVIEST PRECIPITATION IS COMING INTO BETTER
FOCUS BASED ON THE LATEST COMPUTER GUIDANCE. BUT...AS IS TYPICALLY
THE CASE...THE DETAILS OF FCST SUCH AS PRECIPITATION TYPE/LOCATION
REMAIN ELUSIVE AT THIS RANGE. 

ALL MDL SOLNS ARE PORTRAYING A SLOWER...WWD TREND IN SFC LOW
POSITION AS IT EJECTS NNEWD FM THE SRN PLAINS THUR NGT INTO FRI.
THE WRN TRACK SUGGESTS COLD AIR DAMMING E OF THE APPLCHNS WILL BE
MORE PREVALENT...AS STG HI PRES RETREATS INTO NRN NEW ENG/QUE.

MUCH COLDER AIR WILL MOVE INTO THE REGION LATE THIS WEEKEND AND
EARLY NEXT WEEK AS A MEAN TROUGH TAKES HOLD OVER MUCH OF THE ERN
U.S. CYC FLOW WILL KEEP SCT LES SHWRS OVER THE WESTERN AND NORTHERN
MNTS. BLEND OF EC/GFS MEAN HEIGHTS SHOWS THE LW TROUGH LIFTING OUT
AS THE FLOW BECOMES MORE ZONAL INTO EARLY NEXT WEEK.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
PERSISTENT NW FLOW WILL CONTINUE AS A CLIPPER SHORTWAVE SLIDES BY
TO THE NORTH TONIGHT. THIS WILL KEEP LIGHT LAKE EFFECT AND OROGRAPHIC
SNOWS CONTINUING THROUGH THE NIGHT IN KBFD/KJST WITH CIGS BOUNCING
ARND BTWN 700FT AND 1500FT AND VSBYS VARIABLE BTWN 1SM AND 5SM.
EAST OF MTNS...OCCASIONAL MVFR CIGS BTWN 1500FT AND 2500FT
EXPECTED AT KAOO/KUNV ALONG WITH A FEW FLURRIES. ACROSS THE SUSQ
VALLEY...A HIGH CONFIDENCE OF VFR CONDS THE ENTIRE NIGHT AT
KIPT/KMDT.

HIGH PRES RIDGE WILL BUILD INTO THE REGION ON TUESDAY...CAUSING
LGT LAKE EFFECT SNOWS TO TAPER OFF. BY AFTN...CIGS EVEN AT KBFD
WILL LIKELY IMPROVE TO VFR. HOWEVER...LATEST MODEL DATA SUGGEST
MVFR CIGS MAY PERSIST ARND KJST. 

OUTLOOK... 
WED/THU...NO SIG WX EXPECTED. 
FRI/SAT...FREEZING PRECIPITATION/IFR CONDS POSSIBLE.
SAT...IFR CONDS POSS EARLY.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL/DANGELO
AVIATION...FITZGERALD