962 FXUS64 KFWD 110930 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 430 AM CDT Thu Oct 11 2018 .SHORT TERM... /Today through Friday/ Quiescent and rather stellar weather will continue today as high pressure remains in control. High temperatures today will be similar to readings achieved on Wednesday, and will be some 6 to 9 degrees below climatological normals. Things will begin to change pretty quickly this evening and overnight, however, as the surface high begins to build into Missouri. As this occurs, a low-level jet will develop which will allow moisture to spread back across North and Central Texas by Friday morning. A fairly pervasive deck of mid-level cloud cover should spread eastward across the entire forecast area during this timeframe. Robust warm advection/isentropic upglide will accompany this burgeoning low-level jet. As this ascent begins to cool and moisten the 750 to 500 mb layer, a small sliver of instability may materialize across our far western counties late Friday night which should facilitate the development of elevated showers at the leading edge of the low-level jet. The sub-700 mb layer initially looks pretty dry, but there's enough of a signal for convective elements to introduce some low (20-30%) PoPs north and west of a Comanche to Bonham line very late Thursday night and into Friday morning. Warm advection will overspread most of the region through Friday morning and into the early-afternoon hours. I've increased PoPs area-wide, with the best chances (40-50%) mainly across the northwestern half of the forecast area. Overall, instability appears relatively meager, although there may be just enough to support some embedded storms mainly west of I-35 on Friday. Precipitation amounts overall will be pretty light, generally under a quarter of an inch. Finally, high temperatures on Friday will be tricky due to the anticipated pervasive cloud cover and isolated to scattered showers, and a large north-south temperature gradient is possible. I've undercut the blended guidance by a few degrees north of I-20, while nudging them upwards just a hair across Central Texas. Carlaw && .LONG TERM... /Saturday through Wednesday/ Wow - quite the challenging forecast in the Saturday-Monday timeframe, with significant changes depicted in the model guidance vs yesterday's runs. Confidence is quite high that it will rain much of the time over the weekend and early part of next week; what's unclear is the exact timing of precipitation episodes and lulls, and - the potential and exact location of heavy rainfall. The other facet that we're quite confident about is the marked drop off in temperatures Monday-Tuesday, with both days sporting daytime readings unseen in these parts since early April. We may actually approach record low maximum values at DFW both days, if the high temp forecasts verify for those days. First up during this active period: the arrival of Tropical Storm Sergio's remnant lower and mid-level circulation, and attendant moisture field. Despite some placement and intensity differences, the Euro and GFS but both generally move this low center - and its ample moisture field and forcing for ascent - across West and North Texas during the day Saturday. Went along with the model consensus and included very high PoPs across the NW half of our forecast area by afternoon, tapering to chance values in our SE zones. Given precipitable water values above the 90th climatological percentile, good lift and moisture inflow, believe we have a decent potential for localized flash flooding in our Red River and adjacent counties, especially west of I-35. If the remnant tropical low manages to survive its trek over the mountains, and undergoes renewed deepening in the broadly favorable background environment over Texas, then we could see a fairly robust temperature gradient develop across the area by afternoon. With veering winds south of this boundary, we could see daytime temps jump higher than forecast, especially south of I-20. This would also increase our low-level instability, which, coupled with favorable shear, could lead to at least a low-end mini-supercell and tornado threat mainly along and south of I-20. Not a lot of confidence in this scenario, but this will be something to monitor over the next 24-36 hours. The Sergio-related features will move briskly out of our region by Saturday night, followed by the arrival of a strong cold front dropping southward through the western High Plains. Winds will initially swing around to the north after midnight, on the backside of the Sergio low. However, the true front, and its associated much stronger and colder northerly flow, will penetrate North Texas Sunday afternoon. Readings will drop through the 60s by later afternoon, into the 50s by evening. In addition to the strong frontal passage Sunday, our region will find itself sandwiched between the dampening wave that was formally Sergio, and a larger full-latitude positively-tilted trough that will be rapidly evolving over the Rockies. While lift won't be as focused as it was with Sergio, enough mid-level forcing for ascent ahead of the trough, coupled with isentropic lift surmounting the shallow dome of cool, post-frontal air will be sufficient to kick off scattered showers across North Texas on Sunday. Not confident at all about coverage with this activity, but went with 40% PoPs just about everywhere on Sunday for the aforementioned reasons. The Rockies trough will continue move eastward Sunday night into Monday, as cold air advection continues in earnest at the surface. The combination of a low-level overrunning pattern, plus the mid- level trough to our west, will continue to provide favorable forcing for ascent, with mid-level moisture feeding in from the eastern Pacific. Monday promises to be a downright chilly, wet, blustery day, with intermittent rain, gusty northerly winds, and temperatures remaining locked in the 50s. If these temps hold, we could smash the record low maximum for DFW for this day, which is 60 degrees. We'll remain cool Tuesday, but recover a bit by Wednesday, as the mid-level trough passes east of us, and weak ridging commences. The widespread rainfall mass should slide east of our area during the day Tuesday, leaving much smaller precipitation chances for the rest of the week. Morning lows will dip well down into the 40s Monday through Wednesday, especially north of I-20, before recovering a bit during the latter half of the week. Bradshaw && .AVIATION... /Issued 1141 PM CDT Wed Oct 10 2018/ 06 UTC TAF Cycle Concerns---None major. VFR with north flow. South flow possible early Friday. VFR will continue with CAVU anticipated. Northeasterly breezes will increase after sunrise Thursday as mixing of stronger flow down to the surface occurs. Winds may occasionally gust to near 15 knots. A few high clouds are expected to stream in overhead. Winds will become more easterly through the day with southeasterly winds unlikely to occur until closer to the 0900/1200 UTC time frame on Friday. Bain && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 71 58 71 59 72 / 0 10 40 50 70 Waco 73 58 77 62 76 / 0 5 30 50 60 Paris 68 54 66 54 67 / 0 5 40 30 70 Denton 69 56 69 57 69 / 0 20 40 50 80 McKinney 69 54 69 57 69 / 0 10 40 40 70 Dallas 71 59 71 61 72 / 0 10 40 50 70 Terrell 71 56 72 60 72 / 0 5 40 40 60 Corsicana 74 56 75 61 74 / 0 0 30 40 60 Temple 74 60 79 64 78 / 0 5 20 40 60 Mineral Wells 69 57 71 58 70 / 0 20 40 60 80 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 90/66