Weather

292 
fxus61 kctp 111937 
afdctp 


Area forecast discussion 
National Weather Service State College PA 
337 PM EDT Sat Oct 11 2008 


Synopsis... 
a large area of high pressure will hold in place from New England 
to the middle Atlantic coast through early in the coming week... 
resulting in warm sunny days and cool nights. A cold front will 
move across the area mid-week. Near to below normal temperatures 
are forecast by the end of the week. 


&& 


Near term /through tonight/... 
clear skies will occur through much of the night before areas of 
valley fog form toward daybreak. 


Temperatures will cool through the 60s/50s this evening before settling 
in the u30s to middle 40s at daybreak Sunday. Winds will be a0b 5 kts 
and generally from the northeast to east. 


&& 


Short term /Sunday through Sunday night/... 
the dissipation of valley fog around 14z Sunday will yield 
another splendid day across the region with highs about 3-4f 
warmer than today (in the middle to upper 70s). Continued light 
easterly winds can be expected with the ridge of high pressure 
extending from Vermont to the middle Atlantic coast. 


&& 


Long term /Monday through Friday/... 
high pressure surface and aloft will continue above normal 
temperatures early next week. Models suggest a cloud front will 
progress through the extreme northeast/New England region Monday 
and possibly into the middle Atlantic as a weak backdoor fnt...before 
retreating northeastward on Tuesday. Main impact locally would be on 
temperatures...but the ec/GFS both keep the fnt well to the North/East. 
The high amplitude 500 mb ridge axis should begin to flatten into middle- 
week as short wave energy ejects from the deep trough over The 
Rockies. 


HPC had noted some major diffs regarding this system approaching the 
upper Great Lakes...as well as residual energy that may follow. 
However...at this time it appears the operational GFS/ec along 
with the gefs are beginning to converge on a consensus solution 
involving two cloud fronts. The first/trailing cloud fnt associated with 
the lead short wave would weaken and become q-stationary in vicinity of of northern PA 
Tuesday/Tuesday night. The second...stronger and more progressive cloud fnt 
associated with the remaining/shearing energy from The Rockies trough 
would cross the region on Thursday. Used a blend of gmos/HPC probability of precipitation to 
account for timing/uncertainty. 


The mean flow pattern aloft briefly transitions to zonal as the 
early week upper ridge sinks southward into the southern U.S. 


Models and ensembles are now favoring a cooler regime for late in 
the week and into the weekend. Considerable uncertainty/spread is 
noted in the gefs concerning the depth and position of trofing in 
the east...and this is evidenced by the diffs in the operational 
GFS vs. The ec. Regardless...temperatures are forecast to return to 
climatology values and possibly blw normal by next weekend especially 
if the Euro solution verifies. 


&& 


Aviation /19z Saturday through Thursday/... 
extended period of mainly VFR flying conditions and 
light/variable winds will continue into early next week courtesy 
of high pressure...just to the NE of Pennsylvania. Areas of 
radiational fog expected to form in the river/stream valleys of 
the alleghenies/Susquehanna region Sunday morning. Terminal sites 
kipt...kunv...and kaoo may be affected by a 3 to 4 hour period of 
IFR/LIFR visibilities between 10-14z Sunday. 


A cold front is forecast to push into the region late Tuesday/early 
Wednesday...potentially accompanied by reduced...mainly MVFR cigs/vsbys. 


VFR conditions return for the majority of Thursday and Friday. 


&& 


Ctp watches/warnings/advisories... 
none. 


&& 


$$ 
Synopsis...Lambert 
near term...Lambert 
short term...Lambert 
long term...steinbugl 
aviation...Fitzgerald/Lambert