DFW FORECAST DISCUSSION
000 FXUS64 KFWD 230442 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 1142 PM CDT Thu Aug 22 2019 .AVIATION... /06Z TAFs/ Most of the afternoon convection west and northwest of North Texas has dissipated with the loss of surface heating, but a few showers and storms will linger in this same region overnight due to the passage a weak shortwave trough. Any lingering storms overnight/Friday morning will have no immediate impacts at the Metroplex terminals, but may cause some deviations at the Bowie cornerpost. Slightly better thunderstorm chances are expected Friday afternoon with the arrival of a weak front. It is difficult to say exactly where this boundary will end up since convective outflows will alter its movement. For now we have decided to keep the VCTS mentioned at the Metroplex terminals from 21Z to 01Z. Storms should stay well north of Waco, so no impacts are anticipated. Outside of the thunderstorms, VFR will prevail with scattered daytime Cu and scattered to broken high clouds. A south to southeast wind will continue at speeds at or below 12 knots. 79 && .SHORT TERM... /Issued 238 PM CDT Thu Aug 22 2019/ /This evening and tonight/ The upper-level ridge that has been plaguing our region with excessive heat the past several days has retrograded towards the Desert Southwest today. To be sure, it`s still plenty hot, but temperatures are currently running in the low to mid 90s at most locations, as opposed to the upper 90s by early afternoon. Humidity levels are still elevated, resulting in heat indices in the upper 90s to near 100 F, but they should stay below our Heat Advisory criteria. For this evening, some slight chance to chance PoPs were kept in our northwestern counties and along the Red River. Visible satellite has shown a bit of agitated cumulus in these areas. A weak upper-level shortwave trough is making its way through the Texas Panhandle, and perhaps this could provide just enough ascent to get a few showers and thunderstorms going this evening. Anything that develops this evening will be very isolated in nature however, and the overwhelming majority of folks (even where PoPs exist) will not see rainfall, and certainly nothing appreciable. The main concerns if a thunderstorm gets going will be cloud-to-ground lightning strikes and gusty winds. Given that fuels are getting fairly dry out west (and we have seen some respectable wildfires in Palo Pinto and Hardeman Counties during the past week), any cloud-to-ground lightning strikes would bring the risk of lightning fire starts, even as fire weather conditions remain low (see the Fire Weather Forecast for more information). More significantly, this shortwave trough should kick off more widespread convection up in the Sooner State. Flow aloft is relatively weak, which should keep the storms north of the Red River. It is not impossible however that a few of these storms, likely in a weakening state, could creep into our northern fringes, so for that reason, low (20-30 percent) PoPs are indicated during the overnight. Again, rainfall would be light to non-existent in most locations, with a minimal severe weather threat. 37 && .LONG TERM... /Issued 238 PM CDT Thu Aug 22 2019/ /Friday through Next Week/ Ridging aloft will gradually weaken during the first part of the period as weak shortwave troughs move from west to east across the Southern Plains. The first of these features will generate scattered thunderstorms across Oklahoma during the day Friday. The disturbance and its associated convection/outflow will help nudge a front south of the Red River, which will likely be the focus of isolated thunderstorms Friday afternoon and evening across parts of North Texas. Slight chance to chance POPs will hence remain in place across the northern half of the region on Friday, with the better chances occurring along the Red River in the vicinity of the front. That being said, mesoscale processes may actually determine where the best rain chances occur, and we will need to keep a close eye on the locations of any possible outflow boundaries originating from the Oklahoma storms. For most of the region, hot, muggy and rain free conditions will occur on Friday with highs in the mid and upper 90s. A second disturbance will translate the Southern Plains on Saturday, bringing similar, if not slightly higher rain chances to areas mainly along and north of the I-20 corridor. Slight chance POPs, however, will extend southward through the entire forecast area. Severe weather will be unlikely, but a few storms will be capable of producing strong wind gusts each afternoon. The ridge will attempt to rebound on Sunday as the second disturbance exits to the east. This will be fairly short-lived, however, as a larger-scale shortwave is progged to dive southeastward out of Alberta Sunday and deepen over the Plains on Monday. This system will push another cold front southward into the area on Tuesday. Convection may accompany the front, but coverage will likely remain isolated due to the ridge still remaining somewhat present and the better forcing associated with the shortwave remaining to our north. Backing up into Monday, fire weather conditions may become a concern as pre-frontal compressional heating will coexist with a tightening pressure gradient. Hot and breezy weather will be the outcome, and when taking into account the recent dry spell, should result in an elevated fire threat generally along and west of the Interstate 35 corridor. The Monday temperature forecast will indicate triple digit highs for areas roughly along and south of I-20 and along and west of I-35. Mid range model data contains evidence of a deepening low over the Hudson Bay mid to late next week, creating broad troughing across the eastern third of the CONUS. This pattern would bring another cold front southward through the region, perhaps leading to below-normal temperatures just beyond a week from now. However, the GFS is much more aggressive with the pattern shift compared to the ECMWF, so we will keep expectations of any significant relief from the summer heat tempered for now. 30 && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 79 96 78 95 78 / 10 20 20 30 10 Waco 77 96 77 98 77 / 5 10 10 20 10 Paris 74 90 73 87 72 / 20 40 30 40 20 Denton 77 94 76 93 77 / 20 30 20 40 10 McKinney 77 94 76 92 76 / 20 20 20 30 10 Dallas 80 96 78 95 78 / 10 20 20 30 10 Terrell 77 96 77 94 77 / 10 10 20 20 10 Corsicana 76 96 75 96 75 / 5 5 10 20 10 Temple 75 97 75 97 76 / 5 10 5 20 10 Mineral Wells 76 96 74 95 74 / 10 20 20 30 10 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 79/24