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fxus64 khun 131135 aaa 
afdhun 


Area forecast discussion...updated 
National Weather Service Huntsville Alabama 
640 am CDT Monday Oct 13 2008 


Update...for 12z aviation discussion 
&& 


Aviation... 
a broken deck around 4-5k feet will linger through the day...before 
gradually lifting this evening. Brief reduction to MVFR ceilings is 
possible through about 15z. Gusty east/southeast winds are expected again 
today...with gusts to 20kt at times. As winds decouple 
tonight...patchy reduction to MVFR visible is possible toward daybreak 
at kmsl. 


&& 


Discussion.../issued 335 am CDT Monday Oct 13 2008/ 
a rather amplified middle/upper level pattern existed across the 
greater North American domain this Columbus day morning. Analysis of 
earlier 500mb plots yield an unseasonably cold upper low from 
eastern Montana to the NE Great Basin...with some early snows noted 
over this region. 


Upper level high pressure was in place over the Ohio Valley...with 
ridging extending northward across Ontario. Surface high pressure 
over the middle Atlantic along with the upper ridging was helping to 
provide an easterly flow across the Tennessee Valley. This flow was 
producing at times near breezy conditions...especially in our 
mountains with wind gusting 25-30 miles per hour. Lighter winds in the 5-10 miles per hour 
range were common at most other reporting locations. 3 am temperatures were 
on the warm side for this time of year...ranging from the middle 60s to 
lower 70s. 


Isentropic upglide from this easterly flow in the 295-305k range... 
along with daytime heating may be sufficient with afternoon heating 
to produce a stray shower or two. Rain chances if any will remain 
slim as noted in previous discussions. Have reduced rain chances to 
10 percent from the later morning into the afternoon. The influx of 
moisture should slacken tonight. Dry weather otherwise with a couple 
of more days of warm days is in the forecast Tuesday and Wednesday. 
High temperatures for today should warm to around 80 once again... 
despite more clouds than sun. Expect highs to warm a tad more for 
Tuesday and Wednesday. Have held highs on Wednesday into the middle 80s... 
with GFS guidance suggesting upper 80s from the previous 12z run and 
the current run. Will be interesting to see what the ensemble run 
yields...it should be coming later this morning. 


The upper ridge through middle week will move across this region and be 
centered over the northern Gulf Coast by Friday. This will return a 
more zonal westerly flow across the Continental U.S.. this will allow a cold 
front to near the region from the northwest during the Thursday/Friday timeframe. 
The GFS this go around appeared to trim rain chances with the front 
too quickly...while the European model (ecmwf) and dgex painted showers across the 
area. Have decided to keep a slight chance of showers/thunderstorms 
in for this time frame. 


After the front clears the area...dry weather and cooler 
temperatures will be noted across the area for the next weekend. The 
brunt of the cold air...albeit modified Pacific will be felt mainly 
NE of this region. 


&& 


Hun watches/warnings/advisories... 
Alabama...none. 
Tennessee...none. 
&& 


$$ 


Discussion...rsb 
aviation...jll