072 
fxus64 kewx 150215 
afdewx 


Area forecast discussion 
National Weather Service Austin/San Antonio Texas 
915 PM CDT sun Mar 14 2010 


Discussion... 
surface dew points on the rise with widespread cirrus spreading 
eastward across the central and southern County Warning Area ahead of the upper low 
over nm. Meanwhile a cold front was drifting southward across west 
and central Texas and will nudge into the northern County Warning Area in the early 
morning hours. Despite the abundant cirrus...could see patches of 
fog across coastal plains as advection fog pushes inland late 
tonight. Only minor changes to forecast needed. 


&& 


Previous discussion... /issued 651 PM CDT sun Mar 14 2010/ 


Discussion... 
see aviation section. 


Aviation... 
VFR conditions will deteriorate late tonight...down to IFR at 
ksat/kssf/kdrt and MVFR at kaus. Gradual improvement is forecast 
Monday morning to MVFR at kdrt and to VFR elsewhere. However...an 
advection-type fog event is possible early Monday morning and may 
result in LIFR visibilities. Forecast confidence in that event is 
low...so LIFR visibilities have not been included in the tafs this cycle. 
Thunderstorms are forecast to advance east across the area Monday 
evening through late Monday night and may impact area terminals. A 
moderate southeast low level flow will become east-northeast on Monday. 


Previous discussion... /issued 336 PM CDT sun Mar 14 2010/ 


Discussion... 
two weather systems to impact south central Texas during this 
forecast cycle with the models in reasonable agreement. A strong 
compact upper low currently near The Four Corners region will drop 
southeast along the Rio Grande on Monday to near Edwards Plateau. 
Moisture levels and lift steadily increases leading to probability of precipitation over 
the Edwards Plateau and Rio Grande area on Monday. Isolated storms 
will develop over the burro mountains of Mexico and may propagate 
east into the western counties. These storms may approach severe 
levels due to marginal instability, cape, and shear late Monday 
afternoon into the evening. Hail up to one inch is possible. The 
upper low moves east across central Texas Monday night into 
Tuesday while weakening as it encounters a confluent flow aloft. A 
cold front also moves south across south central Texas. Probability of precipitation 
increase Monday night and then decrease on Tuesday. After a warm 
day on Monday, temperatures will be much cooler on Tuesday due to 
clouds and rain. A dry northwest to north flow aloft will create 
fair nearly seasonable weather Wednesday into Thursday. Flow aloft 
becomes more zonal by Friday as another trough and cold front 
approach. The trough and front move through south central Texas 
Friday night into Saturday morning with slight chance to low 
chance probability of precipitation. Fair weather returns late Saturday into next Sunday. 


For Monday, have gone with higher probability of precipitation than mav probability of precipitation out west due 
higher precipitable waters /stronger lift and lower than mav probability of precipitation in the east due 
lack of pws/lift. Otherwise, have gone near mav/mex temperatures 
and probability of precipitation as well as near HPC quantitative precipitation forecast. 


&& 


Preliminary point temps/pops... 
Austin Camp Mabry 51 73 52 64 47 / 0 - 40 40 - 
Austin Bergstrom international Airport 45 73 49 62 45 / 0 - 40 40 - 
New Braunfels Muni Airport 49 75 52 63 47 / 0 - 40 40 - 
Burnet Muni Airport 49 70 48 59 44 / - - 50 40 - 
del Rio International Airport 55 71 52 62 49 / 0 40 80 40 - 
Georgetown Muni Airport 49 70 50 63 43 / - - 40 40 - 
Hondo Muni Airport 49 74 52 64 47 / 0 20 60 40 - 
San Marcos Muni Airport 50 74 52 63 47 / 0 - 40 40 - 
La Grange - Fayette regional 52 72 51 66 47 / 0 - 30 30 10 
San Antonio International Airport 52 75 53 65 49 / 0 10 50 40 - 
Stinson Muni Airport 52 76 54 67 50 / 0 10 50 40 - 


&& 


Ewx watches/warnings/advisories... 
none. 
&& 


$$ 


01/11