296 
fxus64 kfwd 242329 aab 
afdfwd 


Area forecast discussion...updated 
National Weather Service Fort Worth Texas 
629 PM CDT Thursday Jul 24 2008 


Update... 
best forcing and any hit n' miss surface moisture convergence appears 
to be limited to areas SW of the d/fw metropolitan and Waco areas...though 
better instability/and strong large-scale subsidence/ rules over areas 
further east...though a few low- topped showers may occur through sunset 
or 9 PM. 


Have limited slight chance probability of precipitation through middle-evening over the SW portions 
of North Texas...then removed any overnight activity as heating is lost and 
weak focus from the remnants of Dolly continue to drift westward just south 
of the West Texas Big Bend country. 


This weekend looks very hot...as center of strong subtropical upper 
high Parks right over the Red River valley with heights approaching 
595 dm...so temperatures over the century mark this weekend into early next 
week looks likely. Keep The Swimming Pool gear and sunscreen handy. 


05 


&& 
aviation... 
618 PM CDT 


Metropolitan... 
showers are struggling the further they move away from the remnants 
of Dolly. Showers to the south of metropolitan taf sites are encountering a 
somewhat less favorable environment as they move north. A few towering cumulus 
and cumulonimbus will affect tracon through sunset...but probability for 
precipitation at any metropolitan taf site is low. Nonetheless...some 
erratic winds and convective wind shear will be an issue near 
downpours with high bases (6-7kft). Lightning threat is minimal. 


Waco... 
Waco is currently in lull between two batches of convection. Still 
potential for activity in vicinity of lhb/cll to affect kact terminal before 
nightfall. Central Texas activity may linger after dark where deeper 
moisture/instability remains and large-scale subsidence is minimal. 
Regardless...convection is largely diurnally driven and will 
dissipate during the evening hours. 


Tonight... 
Dolly has ushered in considerable low-level moisture for July. 
Despite mixing heights as high as 8kft...surface dew points remain 
in the upper 60s and lower 70s. MVFR ceilings will likely return to 
Waco...with tempo MVFR ceilings at metropolitan sites. Will introduce tempo 
groups for dfw/Dal/ftw/afw with 00z package for planning purposes. 


Friday... 
Ridge will begin asserting itself again...as Dolly becomes less of a 
player for north and central Texas weather. Do not expect any issues 
with afternoon convection for metropolitan sites...though deep moisture and 
minimal inhibition may allow some convection in central Texas. Cap 
may need until Saturday to fully develop and effective suppress any 
and all convection. Probability of rain showers/thunderstorms and rain affecting Waco terminal 
Friday afternoon is too low to include even low-end cumulonimbus coding. 


25 


&& 






Previous discussion... 
245 PM CDT 


Streamer showers associated with Tropical Storm Dolly continue to 
move into southern portions of the forecast area. Coverage is less 
than anticipated and it appears convection is losing a battle with 
middle-level subsidence. Have confined rain chances this afternoon/ 
evening to south of I-20 as development farther north looks 
unlikely. Dolly will weaken to a depression shortly as it moves 
west-northwest. 


The remainder of the forecast looks hot and dry as subtropical 
ridging remains centered over central Texas. Cloud cover and 
additional moisture from Dolly have kept temperatures in check today... 
but an overall increase in thickness values and a decrease in 
moisture throughout the column will encourage triple digit 
temperatures for many locations Saturday through Tuesday. Maximum 
sunshine and light south to southwest winds will make for some of 
the more unpleasant days so far this Summer. Dew points in the 
upper 60s to lower 70s in the east and south will help heat 
indices reach 100-105 degrees. Thankfully overnight lows in the 
east will dip below 78 degrees and preclude any heat advisories. 


Models are hinting at a system by Wednesday or Thursday that would 
bring some relief to the area. The GFS has backed off on a frontal passage 
but the European model (ecmwf) shows a front stalling middle-County Warning Area as a shortwave rounds 
the NE corner of the ridge. This system would represent the next 
good chance of rain for North Texas. Have opted to leave precipitation 
out of the worded forecast at this time until more consistency is 
reached between the models. Sh/13 






&& 






Preliminary point temps/pops... 
Dallas-ft. Worth, Texas 80 98 80 101 80 / 10 10 5 0 0 
Waco, Texas 75 97 75 101 76 / 20 10 5 0 0 
Paris, Texas 73 94 75 99 75 / 10 10 5 0 0 
Denton, Texas 76 97 76 100 75 / 10 10 0 0 0 
McKinney, Texas 75 96 76 101 74 / 10 10 5 0 0 
Dallas, Texas 78 97 81 100 81 / 10 10 5 0 0 
Terrell, Texas 76 97 75 101 76 / 10 10 5 0 0 
Corsicana, Texas 75 95 75 99 75 / 10 10 5 0 0 
Temple, Texas 74 95 73 100 73 / 20 20 5 0 0 


&& 


Forward watches/warnings/advisories... 
none. 
&& 


$$ 


/05