142 
fxus64 ksjt 212318 
afdsjt 


Area forecast discussion 
National Weather Service San Angelo Texas 
518 PM CST Sat Nov 21 2009 




Discussion... 
/see below for o0z taf discussion/ 


&& 


Aviation... 
while skies were clear in wc Texas this afternoon...the NAM and 
RUC models indicate light easterly low level winds returning. With 
good radiational cooling...expect IFR stratus across the eastern 
half of Texas to advect back west across taf sites 6-9z tonight. 


&& 


Previous discussion... /issued 247 PM CST Sat Nov 21 2009/ 


Short term... 
there are no major weather concerns expected over the next 24 hours. 
Lingering low level moisture...which is expected to hang around 
until the front arrives early Tuesday...and radiational cooling will 
lead to the redevelopment of low ceilings mainly after midnight tonight. 
With higher dewpoints and widespread low cloudiness...overnight lows 
are expected to stay near or above 40 in most areas. Using the ups 
fog tool in BUFKIT...it does indicate that stratus is favored over 
dense fog development as surface temperatures are expected to remain above the 
crossover temperatures. However...I will insert some areas of light fog 
given the fairly high surface relative humidity forecast from the NAM. 


After the low ceilings scatter out on Sunday...a nice mild day is in 
store with highs in the upper 60s to near 70. 


Lacy 


Long term... 
the medium range models agree that an upper level low/trough will 
move into the Central Plains on Monday and an upper level low 
moving into the Great Lakes region midweek. The main impact on 
west central Texas will be a weak cold front pushing across the 
area late Monday night into Tuesday morning. The NAM is a little 
slower with frontal passage than the GFS but both models have the front at 
the Interstate 10 corridor Tuesday morning. With the upper level 
low located in the Central Plains the best lift will be north and 
east of west central Texas but have added a slight chance for 
light rain/drizzle early Tuesday morning across the Northwest Hill 
country...where some shallow moisture is located. 


For midweek into next weekend...expect a dry forecast and pleasant 
conditions. Clear skies...dry air and light winds will result in 
good radiational cooling across west central Texas for both Tuesday 
and Wednesday overnight...so have gone a few degrees below guidance 
with near freezing temperatures expected Wednesday morning and below 
freezing temperatures expected Thursday morning. With upper level 
trough remaining in place across the Great Lakes through the end 
of the work week...this will keep west central Texas under dry and 
cool northwest flow aloft...resulting in temperatures being on 
the cool side into the weekend...with afternoon highs in the 60s. 


For next weekend the models diverge greatly with the European model (ecmwf) has an 
upper level ow moving into northern Mexico with GFS has weak ridging 
in place over Texas...so have not strayed far from previous 
forecast. 


&& 


Preliminary point temps/pops... 
Abilene 65 44 67 47 74 / 0 0 0 0 0 
San Angelo 67 40 70 46 75 / 0 0 0 0 0 
Junction 66 39 69 44 74 / 0 0 0 0 0 


&& 


Sjt watches/warnings/advisories... 
none. 
&& 


$$ 


99/99/04