890 FXUS64 KFWD 200726 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 226 AM CDT Sat Jul 20 2019 .LONG TERM... /Sunday onward/ Little has changed with the synoptic pattern across North America during the past 24 hours, with a classic, mid-summer "Ring of Fire" pattern remaining in place. Strong zonal flow continues across the north-central United States, with an 80 knot jet streak centered over eastern Montana and western North Dakota. Multiple mesoscale convective complexes are riding through this flow from the Dakotas to Lake Erie. To the south of the jet stream, a stout subtropical ridge remains anchored across the southern two-thirds of the United States, which will bring record heat to the East Coast this weekend. For the rest of the weekend, the ridge will be the dominant factor, with seasonably hot weather (i.e. hot, but not unusually so for North Texas in late July) will continue. Highs should reach the upper 90s for most locations, with a few spots potentially exceeding 100 F. The one piece of good news is that humidity shouldn't be too out of control, which will keep heat index values below advisory criteria. Saturday and Sunday do appear to be DFW and Waco's last shot at getting their first 100-degree day for at least the next seven days, because a pattern change is coming. Heading into the work week, a deep mid-tropospheric trough will amplify over the eastern two-thirds of the United States, which will drive a cold front south across the Great Plains. This cold front looks to arrive in our northern counties along the Red River some time after daybreak on Monday, reach the Dallas/Fort Worth Metroplex around noon, and clear our southern counties during the evening hours. Rain chances will increase along and immediately behind the cold front, with the strongest lift looking to coincide with the 850 mb cold front (which will lag behind the surface cold front by about 50 miles or so). While we will have the surface cold front, a lack of strong cyclonic vorticity advection aloft should limit larger scale synoptic ascent. Because of this, PoPs are not tremendously high, and were mainly kept in the chance category for now. These PoPs may be bumped up in coming days though as the frontal passage gets within the range of the CAMs, and we get a better idea of what shower/thunderstorm coverage might look like. The bottom line is that many of us will likely see rain showers, and probably a few rumbles of thunder as well, Monday afternoon and Monday night, but rainfall amounts and coverage remain uncertain. With regards to severe weather potential, deep layer wind shear will be limited which should prevent much in the way of organized thunderstorms, but the presence of inverted-V thermal profiles and moderate instability along and ahead of the cold front could result in some strong to marginally severe thunderstorms capable of producing gusty winds and frequent lightning. Rain chances will likely linger through at least part of the day Tuesday, especially across Central Texas, where the surface front will be close enough for some isentropic upglide to keep scattered showers and storms going. Rain chances should be generally on the decrease however, as drier air slowly moves in. It should be noted here that this will not be like a cold season cold front where we see a sharp drop in temperatures and dewpoints with the frontal passage. Given the time of year, the front will be somewhat diffuse, with the trailing air mass being heavily modified. Nevertheless, the persistent northerly winds behind the front should eventually get our dewpoints down into the lower 60s and possibly even upper 50s by Wednesday. Temperatures on Wednesday will also likely struggle to hit 90 for many locations. Given the low dewpoints, and temperatures some 5-10 degrees below normal that are expected, Wednesday is shaping up to be a very nice day by late July standards, so make sure to take advantage of it before the summer heat comes roaring back (and it most certainly will eventually, since we still have to get through August). Finally, as we head towards the end of the week, we should see a warming trend as south flow becomes reestablished, but it looks like it'll be beyond the end of this forecast before truly intense summer heat returns. 37 && .SHORT TERM... /Issued 1123 PM CDT Fri Jul 19 2019/ /Overnight through Saturday night/ Subsidence under a ridge of high pressure will keep seasonably hot and rain-free weather in place across North and Central Texas overnight through Saturday. A weak easterly wave over the Gulf will drift westward through the day Saturday, bringing scattered high clouds to the region. These clouds will have little to no influence on temperatures with overnight lows cooling into the middle and upper 70s. Highs Saturday will be similar to the past several days with middle and upper 90s region wide. The breezy southerly winds will continue through Saturday which will keep the boundary layer well mixed and afternoon heat index values below 105. No major changes are expected Saturday night, but wind speeds may be a bit lighter ahead of a cold front that will be moving through the Central Plains. The lighter wind should result in slightly cooler overnight lows (1 or 2 degrees), but it will hardly be noticeable. 79 && .AVIATION... /Issued 1123 PM CDT Fri Jul 19 2019/ /06Z TAFs/ No changes from the 00Z TAF package with only scattered high clouds overnight and a breezy south/southeast wind. Stratus is still expected to develop across Central Texas overnight, with temporary MVFR ceilings at Waco for a few hours around sunrise Saturday. Otherwise, VFR is expected across the entire region from mid morning Saturday through the evening. A south wind will prevail between 12 and 18 knots along with a few higher gusts. 79 && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 97 78 98 78 93 / 0 0 0 5 30 Waco 97 76 98 75 99 / 0 0 0 0 20 Paris 93 75 93 75 87 / 0 0 5 10 40 Denton 97 77 98 77 92 / 0 0 0 5 30 McKinney 96 76 97 77 92 / 0 0 0 5 30 Dallas 98 79 98 79 94 / 0 0 0 5 30 Terrell 95 76 98 77 95 / 0 0 5 5 40 Corsicana 94 75 94 75 93 / 0 0 5 5 30 Temple 96 74 96 75 98 / 0 0 0 0 20 Mineral Wells 97 74 97 74 91 / 0 0 0 5 20 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 37/91