033 FXUS64 KFWD 100851 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 351 AM CDT Wed Oct 10 2018 .SHORT TERM... /Today through Thursday Night/ Our long-awaited cold front is making swift southeastward progress through the region early this morning. While our northwestern counties are drying out (with dewpoints falling into the upper 40s/lower 50s), ahead of this feature, dewpoint depressions are near 0, and point soundings reveal the presence of a very shallow saturated layer in the lowest 2-300 feet or so. Surface observations show fog is reducing visibilities to under 3 miles ahead of the front, and this shows up well on recent GOES-16 nighttime microphysics RGB imagery. Given the rather localized nature of the very low visibility reductions (under 1/2 mile) and the front's rapid forward progression, we'll hold off on issuing a Dense Fog Advisory for our southern counties. Conditions will improve quickly once winds swing around out of the northwest, heralding the arrival of the drier and cooler cP airmass. We'll hold onto a low (20%) mention of a few showers through daybreak across our far eastern and southern counties where PWATs are still over 1.5". Instability appears much too meager to support a lightning/thunder potential. The rest of the day is shaping up to be pretty stellar, with highs in the upper 60s (north) and upper 70s (south) and dewpoints dropping into the 50s across much of North and Central Texas along with a bit of a northwesterly breeze. Decent radiational cooling tonight with clear skies and decreasing winds as the boundary layer decouples will support low temperatures in the mid and upper 40s across our outlying locales, while 50s will prevail elsewhere. Thursday will be another tranquil and pleasant day. Mid and high- cloud cover will be on the increase Thursday night and into Friday as high pressure begins to shift east of the region and the low-level jet begins to pump moisture northward. Isentropic ascent increases pretty markedly late Thursday night, but a fairly deep layer of dry air (under 700 mb) will exist under the developing mid-level cloud deck. As a result, we'll continue to advertise a silent 10% PoP across our northern and western counties through daybreak Friday. Carlaw && .LONG TERM... /Friday through Wednesday/ The overall upper level pattern trends between the models for the weekend and beyond are fairly similar, but the lower level features show considerable differences this weekend that do not lend much confidence of the forecast Friday through Sunday. Most of these differences affect when the best chances for rain and timing the arrival of front(s) will be. For these purposes, I stuck closer to a blend of the models for now and anticipate changes can almost be guaranteed as we approach the weekend. For the weekend, our attention will be focused on the remnants of Sergio and their track in Texas. Sergio will make landfall on Baja California and Sonora, Mexico on Friday. At the same time, a shortwave disturbance will be detaching along the West Coast from the main longwave trough across the country. Increasing mid-level moisture will spill across the state resulting in higher cloud cover and low rain chances on Friday. The rain chances are generally across the northwestern half of the CWA, and the thunder potential looks limited so only mentioned showers at this time. Friday night is where discrepancies begin between the models. Some of the mid level remnant energy from Sergio is forecast to begin translating into the region Friday night. A weak front may slide into the region during the night and potentially stall. The EC is most aggressive with the southward push of this front, but the NAM may be close in-line. Both the EC and the NAM generate relatively light precipitation along the front, but the GFS keeps a somewhat quiet night with the front stalled to our north. The NAM and GFS generate a surface low pressure system north of the Big Bend area of Texas on Friday night, but the EC is considerably farther southwest into Mexico with the location of the surface low. At this point we reach the end of the NAM run, but the GFS and EC and their respective ensembles track this surface low northeast towards North Texas. However, their arrival is about 12 hours apart. The GFS brings the surface low along the Red River Saturday evening and night with increasing rain chances from west to east Saturday afternoon through the night. The EC's arrival of the surface low and rain is Saturday night into Sunday. In keeping with the NHC track of Sergio, which places the storm as a depression in West Texas Saturday afternoon, I have leaned towards the GFS, with support from the North American Ensemble Forecast System. This results in the best PoPs Saturday-Saturday night. At this point it looks like the heaviest rains will be to our north in Oklahoma, but areas north of I-20 could also have a heavy rain threat with 1-2 inches of accumulated rainfall. We will also be monitoring for a severe weather threat during this time period as shear values will be favorable, but limited surface moisture return may keep instability values too low. A nice front will sweep in behind the low pressure system as an embedded shortwave trough moves across the Plains within the longwave trough. The GFS brings the front through mostly dry while the EC is aggressive with more precipitation along the front. For now will maintain chance PoPs until better consistency appears. The front should leave us mostly dry for Monday (and maybe Sunday depending on its time of arrival), but low rain chances creep back into the forecast by the middle of the week as the upper low that's been hanging out to our west potentially starts to move east. Temperatures in the wake of the weekend front will be the coolest we have seen so far this season and highs on Monday are projected to only be in the 50s and lower 60s, with a brisk north wind that will make it feel cooler. JLDunn && .AVIATION... /Issued 1218 AM CDT Wed Oct 10 2018/ 06 UTC TAF Cycle Concerns---LIFR/VLIFR cigs/vsby and timing of FROPA at all TAF sites. VLIFR/LIFR cigs continue to creep eastward towards Metroplex terminals early this morning with AFW...FTW and DFW likely to be impacted over the next 1-3 hours. IFR to near LIFR vsby will be possible at these sites. The potential for VLIFR/LIFR cigs is lower at GKY and DAL, but non-zero. Post frontal IFR/MVFR appear probable at all Metroplex TAF sites at least through 1200 UTC before drier air invades from the northwest. Gusty northwest winds will be possible in the wake of the front with FROPA between 0700-0800 UTC. By mid to late morning VFR should prevail at all Metroplex TAFs. For Waco...there will be a continued potential for intermittent IFR to LIFR cigs with vsby dipping down to near 2SM at times. FROPA will be a few hours later at Waco with VFR returning during the morning hours. Bain && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 72 53 71 55 74 / 0 0 0 5 20 Waco 75 53 75 57 80 / 0 0 0 5 10 Paris 72 49 69 51 69 / 0 0 0 5 10 Denton 71 49 70 54 71 / 0 0 0 10 20 McKinney 71 49 69 53 73 / 0 0 0 5 20 Dallas 73 54 72 56 75 / 0 0 0 5 20 Terrell 74 51 74 55 76 / 0 0 0 5 10 Corsicana 75 53 72 55 78 / 0 0 0 0 5 Temple 75 53 75 58 81 / 0 0 0 5 5 Mineral Wells 71 50 71 54 77 / 0 0 0 10 30 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 82/90