056 
fxus64 kbmx 211133 
afdbmx 


Area forecast discussion 
National Weather Service Birmingham Alabama 
530 am CST Sat Nov 21 2009 


Updated...for aviation discussion. 


&& 


Short term...today through Monday. 


High clouds remain the only thing we're seeing this morning across 
all of central Alabama...ahead of our approaching system. The 
surface low currently sits out over the western Gulf of Mexico and 
that is where most of the activity is located. Radar is showing 
some very light rain across south Mississippi and southwest Alabama 
that looks like it wants to come into our southwestern counties... 
but as dry as it is...especially aloft...most of these returns will 
dry up before they reach the ground. This will change as we move 
along this afternoon...but there has been a slight change in 
timing. Mex guidance came in much slower tonight and I am inclined 
to follow suit as dry as it is...so I will back off rain for today 
and push most of it off until later this afternoon and tonight. As 
far as tonight is concerned...and really for the entirety of this 
system...we should only see light to moderate rainfall as we will 
remain in an easterly to northeasterly flow...which means we stay 
out of any warm sector and remain fairly stable. 


Sunday will likely be one of those cloudy...drizzly days as this 
system will be in no hurry to push out of the southeast. Wrap around 
moisture is expected to affect most everyone during the day on 
Sunday...and probably into the overnight hours Sunday into the day 
on Monday. Will keep a slight chance in for the extreme northeast 
counties until midday Monday...and this is just to coincide with the 
overall slow down of the system. 


Rainfall totals will likely be heaviest across the south and east as 
the surface low is expected to pass south of the County Warning Area. Storm totals 
should not exceed 1.5 - 2 inches anywhere in our area...with most 
everyone seeing about one inch. 


Temperatures Saturday and Sunday should fall a couple of degrees 
below normals for this time of year as cloud cover should inhibit 
any significant warm up. Temperatures should rebound on Monday as 
high pressure builds in from the west. 


Long term...Tuesday through Saturday. 


Mondays surface high should be fairly short lived as another Rocky 
Mountain shortwave pushes across the center of the country. A cold 
front is expected to accompany this low...but all indications are 
that it will dry up before it even gets here...leaving rain chances 
on Tuesday fairly low. The one thing it will bring with it is some 
drier air and cooler temperatures...but not the coolest of the 
week. The longwave pattern that produces tuesdays shortwave is 
prognosticated to rotate another vorticity maximum north of the state...which 
should give central Alabama a secondary shot of dry and cooler 
temperatures. Friday and Saturday mornings are setting up to be 
the coolest of the week...but still not expecting things to get 
cold enough for a freeze. 


The good news in all of this is that once we get through this 
weekend's weather maker...the remainder of Thanksgiving week looks 
to be dry. 


27 


&& 


Aviation...12z taf discussion. 


Surface low will deepen to our southwest and approach the coastal 
sections by later tonight. Isolated showers will spread into the 
southwest sections and become numerous after 18z at mgm and 
toi. Showers will become numerous to widespread all sections after 
00z. Ceilings above 10000 feet will lower to 5000 feet at all sites 
by 18z. As showers increase MVFR ceilings and visibilities develop...mainly 
after 00z at all sites. 


Ksl 


&& 


Preliminary point temps/pops... 
Gadsden 58 46 56 45 64 / 20 80 60 40 20 
Anniston 61 47 56 44 64 / 20 90 60 40 20 
Birmingham 61 48 56 45 65 / 30 80 50 30 10 
Tuscaloosa 60 50 60 46 68 / 40 80 40 20 10 
Calera 59 50 57 45 65 / 40 90 40 20 10 
Auburn 60 49 57 46 65 / 60 100 50 30 10 
Montgomery 61 51 62 47 69 / 70 90 40 20 10 
Troy 61 51 62 47 69 / 80 90 30 20 10 


&& 


Bmx watches/warnings/advisories...none. 


&& 


$$ 


27/50