FXUS61 KCTP 132013
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
410 PM EDT THU SEP 13 2001

COLD FRONT IS CURRENTLY STARTING TO MOVE SOUTH ACROSS FAR NORTHERN 
PA. THE LEADING EDGE OF THE CLOUD BAND MARKS THE FRONT. RADAR SHOWS 
SHOWERS ALONG THE FRONT IN N PA. SFC DEW PTS REMAIN IN THE 50S 
ACROSS PA...BUT GOOD HEATING IS OCCURING SE OF THE FRONT WITH LOTS 
OF SUNSHINE ACROSS CENTRAL AND SE PA.

EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS CENTRAL PA AFTER 
ABOUT 4 PM AS HEATING CONTINUES AHEAD OF THE FRONT...AND A STRONG 
SHORT WAVE DIGS SOUTHEAST FROM THE GREAT LAKES AREA. THE 12Z 
MESO-ETA SHOWS A BIG INCREASE IN UPWARD VERTICAL MOTION ACROSS 
CENTRAL PA BETWEEN 18Z AND 00Z AS THE FRONT INTERACTS WITH THE 
UPPER-LEVEL SHORT WAVE. LI'S ARE PROGGED TO -6 ACROSS SOUTHERN PA 
THIS AFTERNOON SO THUNDERSTORMS WILL REMAIN A POSSIBILITY... 
ESPECIALLY SOUTH OF I-80. FEW STORMS POSSIBLE N PA TOO...GIVEN 
STRONG DYNAMICS. EXPECT A FEW HOURS OF SHOWERS BEHIND THE FRONT THIS 
EVENING AS VERTICAL MOTION WILL BE FORCED BEHIND THE FRONT BY THE 
STRONG SHORT WAVE.

PARTIAL CLEARING LATER TONIGHT...BUT SC/CU LIKELY ON FRIDAY...AS 
UPPER LEVELS REMAIN ON THE COLD SIDE. SHEAR WILL TEND TO LIMIT 
SHOWER ACTIVITY OFF LAKES HOWEVER. MAYBE A FEW ACROSS N PA.

.CTP...NONE.

MSE/MARTIN



FXUS61 KCTP 131451
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
1045 AM EDT THU SEP 13 2001

COLD FRONT IS CURRENTLY STARTING TO MOVE SOUTH ACROSS FAR NORTHERN 
PA. THE LEADING EDGE OF THE CLOUD BAND MARKS THE FRONT. RADAR SHOWS 
NO SHOWERS ALONG THE FRONT IN NW PA OR SW NY ATTM. SFC DEW PTS 
REMAIN IN THE 50S ACROSS PA...BUT GOOD HEATING IS OCCURING SE OF THE 
FRONT WITH LOTS OF SUNSHINE ACROSS CENTRAL AND SE PA.

EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS CENTRAL PA AFTER 
ABOUT 2 PM AS HEATING CONTINUES AHEAD OF THE FRONT...AND A STRONG 
SHORT WAVE DIGS SOUTHEAST FROM THE GREAT LAKES AREA. THE 12Z 
MESO-ETA SHOWS A BIG INCREASE IN UPWARD VERTICAL MOTION ACROSS 
CENTRAL PA BETWEEN 18Z AND 00Z AS THE FRONT INTERACTS WITH THE 
UPPER-LEVEL SHORT WAVE. LI'S ARE PROGGED TO -6 ACROSS SOUTHERN PA 
THIS AFTERNOON SO THUNDERSTORMS WILL REMAIN A POSSIBILITY... 
ESPECIALLY SOUTH OF I-80. EXPECT A FEW HOURS OF RAIN BEHIND THE 
FRONT THIS EVENING AS VERTICAL MOTION WILL BE FORCED BEHIND THE 
FRONT BY THE STRONG SHORT WAVE.

BASED ON ALL OF THIS...THE CURRENT FORECAST IS PRETTY MUCH ON TRACK. 
WILL UPDATE TO TWEAK THE DETAILS. WORKZONES WILL BE OUT JUST AFTER 
11 AM. ZONES BY 1130 AM.

.CTP...NONE.

MSE



FXUS61 KCTP 130736
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
335 AM EDT THU SEP 13 2001

IR IMAGERY SHOWING BAND OF CLOUDS ASSOCIATED WITH APPROACHING 
CDFRONT...OVER LOWER MICHIGAN AND SOUTHERN ONTARIO. PROGRESS OF 
CLOUDS/FRONT SUGGEST THAT THERE WILL BE A GOOD DEAL OF SUNSHINE 
TODAY...ESPECIALLY CENTRAL AND SOUTHERN SECTIONS. STRONG WINDS 
ALOFT POINT TOWARD THE POTENTIAL OF SVR WX TODAY...MAINLY SOUTHERN 
HALF OF CWA...WHERE SUNSHINE SHOULD PUSH TEMPS TO BTWN 80-85 DEG AS 
FRONT ARRIVES LATE IN THE DAY. FORCING ASSOCIATED WITH DIGGING GRT 
LKS TROUGH WILL LIKELY PRODUCE SEVERAL HOURS OF POST FRONTAL RAIN 
SHOWERS TONIGHT OVER MUCH OF CENTRAL PA. MODELS NEARLY IDENTICAL IN 
TIMING...ENDING THE RAIN OVER THE WEST AROUND 06Z...THEN SE ZONES 
AROUND 12Z. 

FRIDAY...HI PRES BUILDS INTO PA...USHERING IN THE COOLEST AIR OF 
THE SEASON. COLD AIR ALOFT SHOULD RESULT IN CONSIDERABLE AFTN 
CU...ESPECIALLY N MTNS. 850 TEMPS ONLY ARND 2-4C SUGGEST HIGHS FROM 
THE U50S N MTNS...TO U60S LOWER SUSQ VALL. CLEARING SKIES AND LIGHT 
WINDS WILL THEN RESULT IN A VERY CHILLY FRI NITE. A FREEZE SEEMS 
POSSIBLE IN THE COLDER VALLEYS NORTH OF I-80.  

EXTENDED...HI PRES REMAINS IN CONTROL...PROVIDING FAIR WEATHER 
THROUGH EARLY NEXT WEEK WITH MODERATING TEMPERATURES. IN THE DAY 6-7 
RANGE...MEDIUM RANGE MODELS CURRENTLY SHOWING S/WV ARRIVING BY EARLY 
TO MID WEEK. LOOKS LIKE THIS SYSTEM WILL PUSH TROPICAL SYSTEM OUT TO 
OUR SOUTH...BUT WILL GO WITH THE CHC OF SHOWERS ASSOCIATED WITH THE 
UPPER TROUGH ITSELF. 

.CTP...NONE.

FITZGERALD



FXUS61 KCTP 121829
AFDCTP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE STATE COLLEGE PA
230 PM EDT THU SEP 12 2001

ANOTHER SUNNY MILD DAY ACROSS CENTRAL PA THIS AFTERNOON AS HIGH 
PRESSURE MOVES SLOWLY OFF THE EAST COAST. TONIGHT WILL BE MOSTLY 
CLEAR...WITH SOME CLOUDS MOVING INTO THE NW LATE AS THE NEXT COLD 
FRONT MOVES IN FROM THE NW.

COLD FRONT MOVES ACROSS CENTRAL PA THURSDAY AFTERNOON. THE ETA SHOWS 
SOME INSTABILITY WITH COMPUTED SFC BASED LI'S FALLING TO -6 AND 
BUFKIT CAPES BETWEEN 500 AND 1000 J/KG. 850 MB WINDS ARE LIGHT... 
BUT 500 MB ARE PROGGED AS HIGH AS 50 KTS ACROSS THE NORTH DURING THE 
AFTERNOON. BASED ON THIS EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP 
ACROSS THE NRN COUNTIES THURSDAY AFTERNOON...POSSIBLY GETTING AS FAR 
SE AS MDT BY EVENING. WILL GO WITH LIKELY POPS NORTH TO LOW CHC POPS 
LATE IN THE DAY SE. STRONG MID-LVL WINDS AND SOME INSTABILITY MEAN A 
FEW STORMS COULD APPROACH SEVERE LIMITS THURSDAY AFTERNOON...BUT 
WIDESPREAD SVR WX LOOKS UNLIKELY.

THE FRONT MOVES SE OF THE AREA THURSDAY NIGHT. THE MODELS ARE 
INDICATING A FEW HOURS OF RAIN ON THE COLD SIDE OF THE 
FRONT...POSSIBLY EXTENDING INTO SATURDAY MORNING ACROSS THE 
SOUTHEAST. FRIDAY WILL BE THE COOLEST DAY OF THE SEASON WITH HIGHS 
IN THE NORTH NOT GETTING OUT OF THE 50S. A FEW SHOWERS WILL LINGER 
ACROSS THE NRN AND MAYBE EVEN THE CENTRAL MTS FRIDAY AFTERNOON AS A 
STRONG MID-LVL SHORT WAVE MOVES ACROSS THE AREA...ALONG WITH SOME 
LAKE ENHANCEMENT AS 850 TEMPS FALL TO NEAR ZERO.

THE EXTENDED PERIOD LOOKS TO BE DRY WITH A GRADUAL WARMING TREND AS 
LARGE AREA OF HIGH PRESSURE MOVES ACROSS THE AREA.

.CTP...NONE.

MSE