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fxus64 kbmx 051144 
afdbmx 


Area forecast discussion 
National Weather Service Birmingham Alabama 
642 am CDT Sat Jul 5 2008 


Update...for 12z aviation. 


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Short term...today through Sunday. 


Ongoing nocturnal convection is indicative of an atypical early July 
weather pattern. A broad upper-level trough will influence the 
weather east of the Mississippi River this weekend. 500 mb 
heights...associated with this trough...are about 1 Standard 
deviation below normal over Alabama for early July. Early 
morning convection...out ahead of trough axis...extended from 
eastern Tennessee to northern Mississippi. Precipitable water 
values are projected to remain near 1.80 inches...over forecast area 
today...and drop below 1.5 inches over the northern counties on 
Sunday. 


Similar to yesterday...expect showers and thunderstorms this morning 
to become more numerous this afternoon. With lift ahead of 
upper-level trough...daytime heating is not the only factor helping 
to trigger convection. Therefore...expect scattered convection to 
linger well into the evening hours tonight...with at least isolated 
showers and thunderstorms after midnight. Sunday's precipitation 
may be a little more concentrated to the southeast...as upper-trough 
moves over central Alabama. 


Used ensemble MOS averages for maximum temperatures today and 
Sunday. The operational GFS MOS was on the low end of the 
ensemble spread for today and Sunday. By the way...even the high 
end of the ensemble MOS did not capture bhm's maximum temperature of 95 
yesterday. Regarding chances of precipitation...went with the 
ensemble MOS average probability of precipitation for today and Sunday...and the high end 
for tonight. 


03 


&& 




Long term... 
the unusually amplified pattern will give way to surface high 
pressure early next week. Showers and thunderstorms will remain in 
the forecast but become more isolated to scattered in nature and 
driven by afternoon heating. A juicy airmass will remain in place 
across central Alabama...with precipitable water in excess of 1.75 
inches. Little to no steering winds aloft will result in very slow 
moving storms. These two factors will result in locally heavy 
rainfall. Another upper level trough will swing across the 
Mississippi River valley late Thursday...but be in a weakening 
phase as it approaches Alabama. Showers and thunderstorms will 
become a bit more numerous and slightly better organized Thursday 
afternoon into Friday. 


Temperatures next week look very seasonable with highs in the 
lower 90s and lows in the lower 70s. 


12/sirmon 


&& 


Aviation...12z aviation. 


Active convective day expected today...as isolated showers and 
thunderstorms persisted through the night... ahead of an upper-level 
trough. Tcl is the first taf site under the gun for thunderstorms 
early this morning. Otherwise...have thunderstorms in the vicinity at all taf sites from 17z 
to 00z...with cumulonimbi in tafs from 00z to 06z. Expect several taf sites 
will experience a thunderstorm this afternoon...with brief IFR 
conditions. However...VFR conditions will prevail. Light west 
winds expected through 00z...but strong and gusty winds in and near 
thunderstorms. Wet microburst potential is moderate this 
afternoon. 


03 




&& 


Preliminary point temps/pops... 
Gadsden 85 66 87 66 90 / 60 30 40 20 20 
Anniston 86 69 87 67 89 / 60 30 50 20 20 
Birmingham 88 70 89 69 90 / 60 40 40 10 20 
Tuscaloosa 92 70 91 68 92 / 60 50 50 10 20 
Calera 88 69 88 68 91 / 60 40 50 20 20 
Auburn 85 68 85 68 88 / 70 30 60 30 30 
Montgomery 91 70 90 70 91 / 70 40 60 20 30 
Troy 89 69 87 69 89 / 70 40 60 30 40 


&& 


Bmx watches/warnings/advisories...none. 
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$$