Scientific Forecaster Discussion

NWS Discussion
			
				

Area forecast discussion...updated 
National Weather Service Austin/San Antonio Texas 
1132 PM CDT sun may 19 2013 


Aviation... 
low level jet of 30 to 40 knots will continue to bring rich Gulf 
moisture to south central Texas overnight with ceilings lowering to 
MVFR conditions from 06z to about 17z Monday. Clouds will break 
Monday afternoon for mostly sunny skies with VFR category 
dominating all area terminals through late Monday evening. 
Southerly flow will persist for the forecast period with speeds of 10 
to 17 knots and occasionally gusting up to 25 knots...especially 
over the i35 corridor. Kdrt will see VFR conditions through the 
entire cycle. 


&& 


Previous discussion... /issued 815 PM CDT sun may 19 2013/ 


Update... 
dryline along a Langtry to just east of Sonora line moving back 
west. The few moderate cumulus that developed along it have since 
dissipated. Airmass is too capped with weak moisture convergence 
and have removed isolated probability of precipitation for this evening. Re-established 
sensible weather trends for tonight into Monday morning. Remainder 
of south central Texas forecast is on track. 18z models still show 
isolated to scattered showers and thunderstorms Tuesday afternoon 
into Wednesday. A weakening surface boundary moves into south 
central Texas while an upper level trough moves across Texas. High 
convective available potential energy...ample shear...and strong instability suggest a possibility 
of a few strong to severe thunderstorms late Tuesday afternoon 
into evening. 


Previous discussion... /issued 613 PM CDT sun may 19 2013/ 


Aviation... 
scattered/broken clouds about 5kft are depicted by visible satellite photos 
along i35 corridor late this afternoon. These clouds will 
dissipate overnight. However...lower ceilings will develop after 05z 
to 17z Monday with MVFR conditions prevailing for this period 
across the i35 terminals. After 17z Monday...ceilings will lift to VFR 
category for the remainder of the forecast cycle. Southerly flow 
will be dominating through the period with wind speeds of 10 to 
17 knots with occasionally gusts up to 25 knots. Across kdrt...VFR 
conditions to prevail for the entire forecast period. 


Previous discussion... /issued 308 PM CDT sun may 19 2013/ 


Short term (tonight through Monday night)... 
widespread cumulus field across S central Texas/Hill country region 
this afternoon. The cumulus were becoming more agitated across the 
western/northwestern Hill Country along the dry line and will continue 
isolated evening storms across this area. Storm Prediction Center has also brought the 
slight risk area down into the area...so have updated the severe weather potential statement. This 
convection will end with the loss of heating not long after 
sunset. Otherwise little change through Monday night with the dry 
line setting off isolated convection across the western County Warning Area Monday 
afternoon and evening. Continued unseasonably warm and breezy. 


Long term (tuesday through sunday)... 
best chances for any rain this package continue to be late Tuesday 
into early Wednesday as an upper air trough and a surface cold 
front arrive in central Texas during maximum heating late Tuesday afternoon. 
Isolated-scattered thunderstorms developing over north/central Texas 
Tuesday afternoon and dropping southward across the County Warning Area Tuesday 
evening. Storm Prediction Center continues to have much of the County Warning Area in a slight risk 
area. With upper air support and surface convergence along the 
front/outflow boundaries...this convection should continue well past 
sunset into the overnight hours. Decreasing probability of precipitation on Wednesday...as 
lingering surface boundaries and cool northwesterly flow aloft could result 
in isolated storms during the day. The remainder of the forecast 
for Thursday through Sunday looks unseasonably warm and humid...with 
little chance for any significant convection...so have gone with 
silent 5-10 percent probability of precipitation and warmer than guidance temperatures. 


&& 


Preliminary point temps/pops... 
Austin Camp Mabry 73 94 73 94 72 / - - 10 30 40 
Austin Bergstrom international Airport 72 93 72 94 71 / - - 10 30 40 
New Braunfels Muni Airport 71 94 71 94 70 / - - 10 20 40 
Burnet Muni Airport 71 93 71 92 70 / - 10 20 30 40 
del Rio International Airport 76 100 75 99 75 / - 10 20 10 20 
Georgetown Muni Airport 72 93 71 93 71 / - - 10 30 40 
Hondo Muni Airport 73 95 72 96 72 / - - 10 20 30 
San Marcos Muni Airport 73 93 72 93 71 / - - 10 30 40 
La Grange - Fayette regional 75 93 75 93 74 / - - 10 20 30 
San Antonio International Airport 73 95 73 94 72 / - - 10 20 30 
Stinson Muni Airport 73 95 73 95 73 / - - 10 20 30 


&& 


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


$$ 


Mesoscale/aviation...17 
synoptic/grids...04