Area Forecast Discussion
Issued by NWS Dallas/Fort Worth, TX
Issued by NWS Dallas/Fort Worth, TX
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392 FXUS64 KFWD 272051 AFDFWD Area Forecast Discussion National Weather Service Fort Worth TX 351 PM CDT Sat Apr 27 2024 ...New Long Term... .SHORT TERM... /Issued 1226 PM CDT Sat Apr 27 2024/ Mesoscale Update: A warm and humid airmass is in place across North and Central Texas this afternoon with temperatures creeping up toward 80 degrees and dewpoints in the lower 70s. A dryline is still well west across West Texas where scattered severe thunderstorms have developed through the morning. Farther east, a few convective attempts have been noted across northwest Texas where the atmosphere has become strongly unstable and very weakly capped. Thunderstorms will likely increase in coverage in this area through the mid afternoon hours. In our area, latest RAP objective analysis indicates MLCAPE greater than 3000 J/kg at this time with some capping remaining. An aircraft sounding from 11:30 am indicated a deep moist boundary layer with around 70 J/kg of MLCIN remaining. This may be sufficient to keep convection at a minimum across North Texas through the afternoon. Mesoscale domain visible satellite imagery show a generally unimpressive CU field across the region at this time. For now, we`ll keep PoPs generally around 20% through the afternoon. Later tonight, strong forcing for ascent will overspread the region and a well developed squall line is likely to move through North Texas. Favorable low and mid level wind fields along with ample instability will support a significant severe weather threat through the overnight hours. Initial storms will pose a threat for large hail, damaging winds, and perhaps a few strong tornadoes mainly across our northwest counties, while we`ll transition into more of a damaging wind threat overnight along with some embedded QLCS tornadoes. There will also continue to be a threat for flash flooding through the overnight period and into Sunday. Further relevant details from this morning`s discussion have been retained below... Dunn Previous Discussion... /Issued 225 AM CDT Sat Apr 27 2024/ /This Weekend/ A severe weather outbreak is possible this afternoon and tonight. - Very large hail 2+" in diameter, damaging wind gusts upwards of 70+ mph, and tornadoes are most likely in the late afternoon and early evening across North Texas (mainly along and west of I-35). - A line of storms is then expected overnight, bringing the potential for damaging wind gusts and spin-up tornadoes across most of North and Central Texas. - Saturated soils and multiple rounds of heavy rain may lead to flash flooding for parts of the area through Sunday afternoon. - Outside of thunderstorms, it will be windy. Expect sustained south winds of 20-25 mph with gusts upwards of 35-40 mph. The strongest winds are expected this afternoon and evening. Forecast Discussion: There is uncertainty regarding how far east storms will be able to advance this afternoon. Some of the 00Z CAM guidance indicated supercells developing near/in the Metroplex in the open warm sector along a remnant outflow boundary, while some kept the stronger cells in Oklahoma and far Western North Texas closer to the dryline. Either way, supercells supportive of very large hail, damaging wind gusts, and tornadoes are expected to develop this afternoon and evening in or near parts of North Texas. There are only a handful of days each year that I personally ask you to be weather aware. Today is one of those days. The warm/moist airmass ahead of the dryline is very positively buoyant with MLCAPE values over 3000 J/kg and mid-level lapse rates approaching 8 C/km. This alone provides enough instability to support robust updrafts capable of producing large hail. When you factor kinematic parameters, the hail and tornado potential increases even further...particularly late in the afternoon and overnight when a robust shortwave trough and jet streak move over the Southern Plains. The net result of this will be favorable shear vectors for supercells and tornadoes. Additional storms are expected to develop this evening to our west as the more robust shortwave trough intersects the dryline. Very strong forcing for ascent and favorable shear vectors will allow for quick upscale growth, changing the convective mode to linear in short-order. The line of storms is expected to move into our western counties around midnight and move east through the early morning hours. The main threat with this activity will be damaging wind gusts and spin-up tornadoes along the leading edge of the line of storms. While some stabilization will occur overnight, strengthening low-level flow and a resurgence of moist advection will preclude too much nocturnal stabilization...meaning the line of storms will be more than sufficient to overcome any capping. Of course, this will be harder the further east the storms travel, so we do expect an eventual downward trend in storm intensity after the storms move through and east of the I-35 corridor early Sunday morning. The severe threat is lower across our eastern row of counties compared to those northwest of the Metroplex today and tonight. The opposite is true Sunday. The line of storms will be able to sustain through the night, with a broken cluster of storms ongoing early Sunday morning for areas east of I-35. By this time, the line should be mostly parallel to the deep-layer flow, resulting in an increased risk of training storms and heavy rain. The Flood Watch may need to be extended and expanded southeast, but we will hold off on any configuration changes at this time. As the cold pool lingers over our area Sunday, afternoon destabilization will allow for a gradual uptick in storm intensity across the eastern third of our forecast area. While the parameter space is not as favorable as it will be today, there should be sufficient shear and instability to produce large hail, damaging wind gusts, and isolated tornadoes. Bonnette && .LONG TERM... /NEW/ /Monday Onward/ A lull in the active weather will occur on Monday as the multitude of upper level systems responsible for this weekend`s thunderstorms shift to the east, and a weak ridge develops overhead. Storm chances will return on Tuesday, however, as a shortwave rounds the northern flank of the ridge. This will help ignite thunderstorms along the dryline, which will be positioned across the Big Country by Tuesday afternoon. These storms should remain confined to the western half of the region, keeping the severe weather potential largely west of the I-35 corridor. A secondary batch of convection may also occur across the southeast zones where an active seabreeze may infiltrate Tuesday afternoon. The southeast storms will likely remain sub-severe, though a few may produce gusty winds and heavy rain. By Wednesday, a stronger shortwave will be dropping southeast through the Rockies, weakening the ridge and generating another round of dryline convection across the Big Country mid to late afternoon. A warm and unstable environment along with 35+ knots of effective shear will support more severe thunderstorm potential as convection spreads east through the region Wednesday evening. Storms will dissipate Wednesday night as instability wanes and a capping inversion strengthens at the 850-700mb level. A cold front will then approach on Thursday as the shortwave trough traverses the Plains, providing another focus for showers and storms along with the dryline Thursday afternoon and evening. Widespread convection will be the result Thursday afternoon through Thursday night, with activity pushing south of the region along with the front on Friday. A short reprieve in rain chances will occur Friday into Friday evening before a shortwave embedded in the subtropical jet generates another round of precipitation Friday night into next Saturday. All of the forecast area should be in the cool sector following the frontal passage, keeping any thunderstorms elevated in nature and resulting from isentropic ascent. This should limit the severe potential, but a strong storm or two would be capable of producing hail. After a seasonably cool and damp (next) weekend, a strengthening ridge aloft should lead to a warm-up and a rain-free start to the following week. 30 && .AVIATION... /Issued 1226 PM CDT Sat Apr 27 2024/ /18Z TAFs/ Cigs have lifted through the morning and have generally become VFR around 3500 ft early this afternoon with VFR expected to prevail through much of the afternoon and early evening. We`ll monitor for potential thunderstorm development within the D10 airspace this afternoon/evening but right now it looks like most of the activity will remain off to the northwest into the evening. MVFR cigs are expected late this evening ahead of an approaching line of severe thunderstorms which will move across North Texas overnight. Timing is fairly consistent among the guidance and will include a VCTS by 7Z with a TEMPO for +TSRA from 9-11Z. This line will likely be severe and include a threat for damaging winds, hail, and a few tornadoes. This line of storms will move east early Sunday morning and we`ll have to see what impact it has on additional storm development Sunday afternoon. Dunn && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 66 79 65 86 68 / 100 80 0 5 5 Waco 68 77 64 85 67 / 80 100 10 5 10 Paris 67 75 63 82 63 / 50 100 20 5 5 Denton 63 79 61 85 66 / 100 60 0 5 5 McKinney 66 77 63 83 66 / 90 90 5 5 5 Dallas 67 79 64 86 67 / 90 90 5 5 5 Terrell 68 77 64 83 65 / 60 100 10 5 5 Corsicana 71 79 66 85 68 / 40 80 20 10 10 Temple 68 79 65 85 68 / 70 80 10 10 10 Mineral Wells 62 83 59 86 65 / 90 30 0 5 5 && .FWD WATCHES/WARNINGS/ADVISORIES... Flood Watch through Sunday evening for TXZ091>095-100>107- 117>123-131>135-144>146-159. Wind Advisory until midnight CDT tonight for TXZ091>095-100>107- 115>123-129>135-141>148-156>162-174-175. Flood Watch from Sunday morning through Sunday evening for TXZ147-148-160>162-174-175. && $$