352 FXUS64 KFWD 121233 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 733 AM CDT Tue Jun 12 2018 .UPDATE... Quick update this morning to address upstream convective complex. The storm complex across parts of Central and Eastern Oklahoma continues to plow southward. With the complex maintaining its linear structure a bit longer than suggested by CAMs through sunrise, there's an increased potential that it'll survive southward as surface based convective inhibition erodes with the onset of diabatic heating. While I'm a little hesitant to blindly follow suite with the 10 UTC HRRR, building instability and convergence along a probable outflow boundary should equate to a realistic chance for this thunderstorm complex to continue southward. Strict extrapolation yield a time of arrival of around 15 to 18 UTC around the Red River. For this time frame, I've raised PoPs considerably. Farther south, there is still a large degree of uncertainty as to what happens this afternoon. Again, the 10 UTC HRRR offers a plausible scenario in which the convective cells develop along the leading edge gust front/outflow. Forecast soundings also suggest that the boundary layer will become hot and well mixed with inverted-v profiles. This will support large DCAPE values and the potential for thunderstorm clusters along southward propagating outflows. I've nudged PoPs upward across parts of North and East Texas where this seems more likely. In terms of severe weather, the potential is certainly non-zero. While deep layer shear will be lacking, thunderstorms that do re- develop will do so in an environment characterized by steep 0-3 km lapse rates and DCAPE values near 1500 J/kg. This will necessitate a downburst risk with severe-caliber wind speeds. 24 && .AVIATION... /Issued 657 AM CDT Tue Jun 12 2018/ 12 UTC TAF Cycle Concerns---MVFR stratus cessation & afternoon convective chances. Patchy MVFR stratus continues its trek northward this morning aided by a 20 to 30 knot low level jet. This stratus will gradually lift and erode through the 15-16 UTC time frame with VFR likely through the rest of the morning. The attention will then turn upstream across Oklahoma where a line of TS continues to plunge southward. At this time, it appears more likely that a bulk of this activity will make it to the Red River such that disruptions to the Bowie cornerpost and northbound departures appear more probable. The convection may become less linear and more cellular as it nears the I-20 corridor from the north and thru midday. Additional SHRA and TS clusters are expected to develop along an outflow boundary and as a result, I've elected to add in a mention of VCTS between 19-22 UTC for this afternoon at the Metroplex. While not reflected in the current set of TAFs, an outflow boundary may result in a brief wind shift to the north. This and the potential for TEMPO TS will be monitored through the morning hours. For Waco, I've kept the TAF precipitation-free, but if the TS complex across Oklahoma is able to maintain more of a linear structure, an inclusion of VCSH or VCTS may be needed. MVFR stratus may attempt to make another run at the Waco TAF site on Wednesday morning and for now, will have cigs around FL030. The potential at the Metroplex TAFs is non-zero, but too low to include in the TAF at this time. 24 && .SHORT TERM... /Issued 321 AM CDT Tue Jun 12 2018/ /Today and Tonight/ The main challenge during the short term will be the potential for showers and a few thunderstorms this morning, this afternoon and early Wednesday morning. Otherwise, it'll be hot with daytime temperatures in the upper 90s to near 100 degrees with overnight lows in the mid to upper 70s. Regional radar imagery this hour indicated a stout cluster of storms was diving southward out of the Flint Hills of SE Kansas. WSR-88D VWPs in advance of this complex sampled an unseasonably strong LLJ of around 25 to 35 knots this morning and this will likely fuel the storms over the next 2-4 hours. A strong consensus of NWP, indicates that the magnitude of the low level wind field will gradually veer and diminish towards daybreak with 850mb winds falling to or below 20 knots. This would result in the swift demise of this complex and at this time, this appears like the most probable solution. As such, I'll maintain just a low chance for showers and storms along the Red River from mid- morning into the early afternoon hours. While the veering and weakening LLJ this would certainly limit the influx of higher theta-e air into the MCS and thus support the conservative PoP forecast, there is a big caveat that could result in its sustenance farther south than advertise. If convection is able to continue through sunrise, it's possible that surface based inhibition could diminish enough such that new updrafts develop and continue to trudge southward along the advancing cold pool and beneath the northerly steering flow along the eastern periphery of the H5 ridge. If this scenario is to unfold, some noteworthy changes to forecast PoP, Wind, QPF and T grids will be required. Again, it's probable that this activity will diminish with just some remnant outflow slipping south of the Red River. This potential seems high enough and I'll keep a 20 PoP between HWY 380 and the Red River even in the afternoon hours. Additional afternoon convection is anticipated as the sea breeze front across the upper Texas Coast develops. Similar to the past several days, showers/storms will likely reinforce this boundary northward via stochastic outflow collisions. The most probable locations for this afternoon convection will be across the Brazos Valley and East Texas. We will have to monitor the potential for storms capable of strong winds this morning and especially this afternoon when the potential for downburst winds will be greatest. Otherwise, it'll be hot today with widespread mid to upper 90s for temperatures. A few temperature readings near or just above 100 degrees will be possible west of the HWY 281 corridor where the influence of the H5 ridge will be the greatest. Heat index values will climb into the 103-105 degree range today. With heat index values expected to be a tad lower on Wednesday (upper 90s), we'll forgo the issuance of a Heat Advisory. Overnight into Wednesday morning will remain mild and sultry as low level winds remain elevated and minimize boundary layer decoupling. 24 && .LONG TERM... /Issued 321 AM CDT Tue Jun 12 2018/ /Wednesday through Monday/ Upper level high pressure will remain centered near the Texas/New Mexico border on Wednesday while a weak cold front stalls out across the Central Plains. Thunderstorms will likely accompany the cold front but these should weaken as they move into more stable air near the Red River. Morning clouds associated with the dying storm complex as well as some northward moving stratus will all scatter or clear by Wednesday afternoon allowing temperatures to warm into the mid 90s. The ridge of high pressure will build eastward Wednesday night through Thursday which will keep hot and subsident air in place. However, a few afternoon showers and thunderstorms may still develop across the extreme southeast zones as the sea breeze front moves northward from the upper Texas coast. The ridge axis is progged to move east of the region on Friday while an upper trough moves northward across the Gulf of Mexico. As this upper trough approaches the Texas Coast it will bring a significant increase in deep layer moisture through the weekend with increasing precipitation chances from south to north. Precipitable water values are forecast to reach or exceed 2 inches across the forecast area Sunday and Monday. The combination of moisture, surface heating and weak perturbations on the western periphery of the upper ridge will result in scattered to numerous showers and thunderstorms, especially as we move into early next week. These storms will be efficient rain produces and should bring some much needed moisture to the parched ground currently in place across much of North and Central Texas. High temperatures this weekend through early next week will gradually cool due to the increase in moisture/cloud cover with near normal values in the upper 80s and lower 90s expected by Monday. Lows will remain in the 70s through early next week. 79 && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 96 78 96 77 96 / 30 10 10 5 5 Waco 98 74 96 74 96 / 10 10 10 5 10 Paris 93 75 93 73 93 / 40 20 10 5 10 Denton 96 76 95 75 96 / 30 10 10 5 5 McKinney 95 76 95 72 94 / 30 10 10 5 5 Dallas 97 78 97 78 97 / 30 10 10 5 5 Terrell 95 75 95 74 95 / 30 20 10 5 5 Corsicana 96 75 95 74 95 / 20 20 10 5 10 Temple 97 73 95 73 94 / 10 10 10 5 10 Mineral Wells 98 75 96 73 96 / 10 10 5 0 5 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 24/79