571 FXUS64 KFWD 100541 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 1141 PM CST Sat Feb 9 2019 .AVIATION... /06Z TAFs/ Challenge continues to be timing/trends of lowering CIGs/VSBYs at all TAF sites through Sunday night. Regardless, expect most locations to remain at IFR/LIFR CIGs through most, if not all, of their respective TAF periods. Surface winds have begun to veer more notably to the southeast, in response to one shortwave impulse lifting away from North Texas. VSBYs have risen slightly / held above IFR levels at all sites recently, perhaps due to a slight weakening of low-level ascent in the wake of this impulse. Therefore, prevailed 6SM at all sites for a few more hours, with TEMPO 3SM. As a broader trough to the west (and another embedded impulse in leading southwesterly flow) approach towards 10-12Z, rain/drizzle should be reinvigorated over the region. Expect this to slowly reduce VSBYs from this time period onward, although small fluctuations between MVFR and IFR are possible through mid-day. CIGs will likely remain IFR or lower overnight into the day tomorrow. KACT may have a greater likelihood of LIFR CIGs by 08-09Z this morning, but confidence was too low to include in the TAF at this time. With that said, expect another round of low-level moistening through the afternoon and evening tomorrow, given gradual height falls to the west and a strengthening, poleward mass response over our region. Therefore, continue to show all sites with CIGs lowering below 005 Sunday afternoon. Additionally, VSBYs should gradually lower into the evening and overnight. Prevail 1SM by 21Z at KACT and 01Z at Metroplex sites, and some potential exists for LIFR/VLIFR during the overnight hours. However, confidence remains too low to introduce at this time range. Picca && .UPDATE... /Issued 927 PM CST Sat Feb 9 2019/ /Tonight/ Only notable change with this update is increasing PoPs in the near-term from the I-35 corridor northeastward towards Paris. Light echoes have blossomed from Central Texas to DFW and then northeast to the ArkLaTex this evening, and KFWS data illustrated some enhancement of winds veering with height over the last several hours (correlating with increasing warm-air advection). This round of precipitation should gradually lift north/northeast through the early morning hours, followed by another round (or simply another expansion of ongoing echoes) of light rain developing towards daybreak. Surface temperatures are above freezing across the vast majority of North and Central Texas this evening. The only exception is near the Red River, where some modest wet-bulb cooling and neutral surface temp advection has kept a few sites near 32 F. Still, further veering of winds to a slightly more southeasterly direction should gradually push temps to around 33-34 through the night. Additionally, temps are not expected to fall any lower than 32, such that impacts on road surfaces are not anticipated. Picca && .SHORT TERM... /Issued 231 PM CST Sat Feb 9 2019/ /Tonight/ Cold and very dreary conditions are anticipated through the overnight hours across North and Central Texas. Temperatures at this time appear that they will be high enough to mitigate the potential for any freezing rain/drizzle. Light rain continues this afternoon across North and East Texas in response to isentropic ascent along the 295-310K theta surfaces. While the depth of the lower tropospheric moisture isn't overly impressive, it appears sufficient for measurable rainfall across the area and this is likely to continue periodically through the overnight hours. Some model guidance indicates some gradual drying aloft and so we may see some periods of drizzle as well waves of very light rain. I'll keep PoPs in the 40-70 percent range across the area, but the threat for thunder looks low with generally poor lapse rates. Initially, it was thought that surface temperatures would be low enough to support a round or two of light freezing rain/drizzle across the Big Country and along the Red river. Northeast surface winds could certainly support this potential as wet-bulb cooling would help temperatures fall below 32. However, latest guidance and observations indicate more of an easterly wind field across the area which hampers the magnitude of dry air advection. While temperatures may cool initially due to evaporative effects, the lack of a continual feed of dry air should mitigate the potential for sustained sub-freezing temperatures and thus a threat for icing. Moreover, the latent heat release associated with freezing coupled with veering low level flow (thus WAA) should allow temperatures to remain just above freezing. As such, I've removed any frozen/freezing precipitation from the worded forecast, but an occasional report of a very thin glaze of ice is not entirely out of the realm of possibility on elevated surfaces such as powerlines, road signs and tree branches. Road surfaces should remain just fine. Bain && .LONG TERM... /Issued 231 PM CST Sat Feb 9 2019/ /Sunday through Saturday/ Sunday morning should start off cloudy and cool with areas of drizzle and fog and perhaps some areas of light rain as persistent warm advection continues atop a slowly modifying cold airmass. The warm advection will be maximized along the I-35 corridor into our northeast counties through the day which is where we'll have the highest PoPs. As we get into the late evening and nighttime hours, large scale forcing for ascent will increase as a fast-moving lead disturbance swings across northern Mexico into North Texas. The main upper shortwave will spread through the four-corners region by early Monday morning. With the cold airmass currently in place being eroded by Sunday night, temperatures are likely to remain steady or increase through the overnight hours into Monday morning. On Monday, with the main shortwave ejecting from the southwest U.S. and into the Plains, a surface low will develop and race northeast into Kansas. Low level southerly flow will increase and we may have some instability by afternoon for a few thunderstorms mainly east of I-35. Rain chances will continue into Monday evening when a cold front swings through the region. Tuesday and Wednesday should be precipitation free with temperatures warming back above normal by Wednesday afternoon. On Thursday, another disturbance will swing through the Central Plains with winds becoming more westerly across North Texas. This should allow temperatures to climb into the mid 70s especially west of I-35. Some low chances for rain will occur across our far eastern counties with this system on Thursday, but the bulk of any precipitation should be well to our east. Another front will slide through the region Thursday night. Dunn && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 36 47 47 67 41 / 70 80 90 60 20 Waco 35 48 48 69 42 / 50 60 50 50 20 Paris 33 43 43 62 40 / 70 90 100 80 30 Denton 35 45 45 67 38 / 70 80 90 50 10 McKinney 34 46 46 65 40 / 70 80 90 70 20 Dallas 37 47 47 67 42 / 70 80 90 60 20 Terrell 36 47 46 67 41 / 70 70 80 70 20 Corsicana 36 49 48 66 42 / 60 60 70 70 30 Temple 35 49 49 69 43 / 40 50 40 40 20 Mineral Wells 33 46 46 68 37 / 40 50 60 40 10 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 11/30