552 
fxus61 kctp 061933 
afdctp 


Area forecast discussion 
National Weather Service State College PA 
333 PM EDT Monday Oct 6 2008 


Synopsis... 
strong Canadian surface high will build into northern Pennsylvania 
tonight bringing widespread cold overnight. Many areas will 
experience their first frost or freeze of the season. The high 
pressure will hold fair weather into Wednesday. Unsettled 
conditions will return for the second half of the week as the high 
drifts offshore and Gulf moisture is pulled northward. 


&& 


Near term /until 11 PM this evening/... 
surface high building southward with northerly flow in the low levels 
delivering very dry air with few-scattered cumulus across the north (and 
northeast especially) where lapse rates are steepest. These clouds 
will disappear rapidly late this afternoon with ideal radiational 
cooling conditions developing by late evening. 


&& 


Short term /11 PM this evening through 6 PM Tuesday/... 
previously collaborated freeze warnings and frost advisories 
continue unchanged...with low precipitable waters  resulting in Crystal clear skies 
and surface high allowing winds to drop to near calm for most. 
Much of northern PA will go below freezing and most of the rest of the 
area should sink into the middle 30s. Some low spots and typical cold 
sinks like kthv and kseg *may* even drop to/below freezing...but not 
confident enough in that possibility to Post a freeze warning for 
those locations quite yet. Some upper 30s may be found on the 
hilltops...especially in The Laurels...as indicated in published grids... 
and the urban areas in the southeast may also stay warm enough to 
preclude frost. However the suburbs and rural areas of their 
respective counties should get into the m30s. 


Four counties in the northern mts had a hard freeze 2 nights ago...and 
no further frost/freeze products will be issued for them this 
season. 


Tuesday looks like a very sunny day that will allow greater than 
30f rebound from morning lows to the afternoon maxes. Maxes will be 
close to today/S nums...and maybe even a bit milder. 


&& 


Long term /Tuesday night through Monday/... 
high pressure will start the period...but some showers may 
encroach upon the western zones by late Wednesday or Wednesday night as the 
high drifts offshore and Gulf moisture is pulled northward. Both 
GFS and ecmfw push weak trough through Wednesday night into Thursday with 
chance for showers. 


Then surface high builds in for late week. Upper level features 
differ quite a bit between GFS and European model (ecmwf) in later periods. GFS 
develops upper low over the southeast states and slides it up the coast 
along with increasing moisture through the weekend. Ecmfw also 
shows upper low over the southeast...but it gets thwarted by high 
pressure ridge building over the region this weekend. Tough 
forecast for the weekend...but leaned more toward the drier European model (ecmwf) 
solution and mentioned only low chances for precipitation mainly in the 
southeast this weekend. 


&& 


Aviation /19z Monday through Saturday/... 
high pressure slides southeast through midweek providing decent 
radiational cooling at night and River Valley fog development 
west/reduced visibilities to MVFR/IFR conds after 06z Tuesday and again after 06z 
Wednesday. 


Early Thursday/Friday a frontal boundary approaches from the southwest and 
could bring low level moisture and a chance for rain showers and reduced 
cigs/vsbys. 


&& 


Ctp watches/warnings/advisories... 
freeze warning from 2 am to 8 am EDT Tuesday for paz004-012- 
017-018-037-041-042. 
Frost advisory from 2 am to 8 am EDT Tuesday for paz019- 
024>028-033>036-045-046-049>053-056>059-063>066. 


&& 


$$ 
Synopsis...dangelo 
near term...devoir 
short term...devoir 
long term...rxr 
aviation...devoir/beachler