619 
fxus61 Kiln 210608 
afdiln 


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


Synopsis... 
an Alberta clipper will push through the region overnight and 
early Friday...but with limited moisture and strength. The result 
will be scattered snow showers diminishing to flurries late 
Friday. High pressure and colder temperatures will build in for 
most of the weekend. 


&& 


Near term /until 6 am this morning/... 
instability a little weaker than what was apparent in previous 
runs...but still increases near 06z as shortwave sharpens up. Better 
chance of -shsn will be in northern forecast area...as shortwave along 
with intensifying vorticity maximum swings through area. Some areas may see 
a half inch or so of accumulate in the northern Miami Valley and upper 
Whitewater valley. Have cut back precipitation chances in very far 
south and west slightly...as best moisture and lift will be from 
west central Ohio through the Miami and Whitewater valley areas. 


Continued with slight undercut of mav MOS...though not by much. 
Even with 800 mb temperatures into the negative teens...enough clouds to not 
drop temperatures too much. 


&& 


Short term /6 am this morning through Saturday night/... 
with secondary shortwave moving east through forecast area beginning Friday 
morning...overall decrease of coverage. But will linger -shsn 
after 18z in the north with some more fetch off of Lake Michigan. Just 
flurries through early afternoon in the SW forecast area as through pulls to 
east of area and winds shift more westerly. 


Skies gradually clear out...brining coldest temperatures of the 
season for Friday night. Some middle/upper moisture pushes through 
during the day on Saturday to bring some clouds. Then mostly clear 
for Saturday night. 


Have continued to go a little lower than guidance with 850 temperatures 
from -10 to -13. Question will be whether or not some very light 
accumulations will occur...so upper Miami Valley may need to be 
undercut even more. 


&& 


Long term /Sunday 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 into early Monday. The chance for 
prcip 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 /06z Friday through Tuesday/... 
MVFR ceilings will persist until 13-14z when drier air will allow 
cloud bases to increase to VFR category. Isolated snow showers 
will probably not reduce visibilities at taf sites. 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...jdr 
near term...jdr 
short term...jdr 
long term...jtd 
aviation...coniglio