605 
fxus61 Kiln 211138 
afdiln 


Area forecast discussion 
National Weather Service Wilmington Ohio 
638 am EST Friday Nov 21 2008 


Synopsis... 
cold air flowing across the Great Lakes will bring scattered snow 
showers to the area this morning. High pressure will build into 
the Ohio Valley this afternoon and remain in control through the 
weekend... offering dry conditions and below normal temperatures. 
A cold front will push across the region on Monday bringing the 
next round of precipitation. 


&& 


Near term /until 6 PM this evening/... 
highly amplified upper level pattern with northwest flow continuing 
to dominate our weather. Surface high pressure to nose into the Ohio 
Valley this afternoon. Favorable fetch off Lake Michigan will continue 
this morning before backing with snow showers coming to an end. Have 
continued mention of scattered snow showers this morning in west central and 
isolated elsewhere. Have trended todays high temperatures a little below mav 
guidance with 800 mb thermal trough over the region today. 


&& 


Short term /6 PM this evening through Sunday/... 
with high pressure building in tonight expect skies to clear 
out. Clear skies and light winds and dry airmass will bring 
the coldest temperatures of the season tonight. Have trended 
tonights lows a little below mav guidance values. 


Surface high pressure will continue to dominate on Saturday. 
Middle level short wave embedded in the flow to drop through the Ohio Valley 
Sat aftn/night. This system will be weakening and with lack of 
deep moisture or significant forcing only expect an increase in 
middle/hi level clouds. Favorable isentropic lift develops Sat 
during the day and have increased sky cover. Temperature wise...have 
continued trend going a little cooler than guidance for highs Sat. With the 
passage of the middle level system...expect middle level ceilings to thin 
our Saturday night leaving only some high level clouds. With low 
level flow going southerly on back side of retreating high 
pressure have stayed close to guidance temperatures. 


Middle level flow backs more westerly on Sunday with height/thickness 
rises allowing for some moderation of temperatures. Have trended 
sundays highs a little warmer based on trends. 


&& 


Long term /Sunday night through Thursday/... 
am going along with HPC solution whereby a preferred blend of the 
00z European model (ecmwf) and 00z/12z GFS was used for this extended. Weighed more 
toward the European model (ecmwf) early in this period...and with more of a blend 
during the later part of this extended. Since the ensembles pointed 
toward favoring this solution...utilized the GFS ensemble mean to 
guide temperatures during this period. 


The general solution shows surface high pressure on the East Coast 
coupled with an approaching front from the northwest keeping southerly 
flow across the area on Sunday night into early Monday. The 
chance for precipitation will increase Monday night in advance of this 
front...while frontal passage will occur during the day Monday. 
Given the somewhat milder boundary layer...expect a mix of rain and/or 
snow to develop Monday night. Monday however will see a change 
over to mainly rain showers as the boundary layer shows primary 
support for liquid precipitation. On the back side of this 
system...expect a mix with and change to snow showers Monday 
night. Precipitation should diminish on Tuesday as the low pressure 
system exits and high pressure begins to build in from the west. 
This high pressure system should control the weather through the 
end of this extended period. 


&& 


Aviation /12z Friday through Tuesday/... 
conditions have improved to VFR and are expected to remain so 
through the forecast. Sky cover will consist of cumulus and 
altocumulus which will dissipate by 23z...with high clouds moving 
in after 23z. Northwest winds gusting over 20 knots will shift to 
west at around 23z and subside to under 10 knots. 


Outlook...MVFR ceilings/visibilities possible due to rain and snow showers 
on Monday and Tuesday. 


&& 


Iln watches/warnings/advisories... 
Ohio...none. 
Kentucky...none. 
In...none. 


&& 


$$ 
Synopsis...Arkansas 
near term...Arkansas 
short term...Arkansas 
long term...jtd 
aviation...coniglio