Area Forecast Discussion
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Issued by NWS
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973 FXUS64 KLUB 291727 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 1227 PM CDT Mon Apr 29 2024 ...New AVIATION... .SHORT TERM... (Today and tonight) Issued at 330 AM CDT Mon Apr 29 2024 As of 1 AM CDT, midlevel satellite water vapor analysis shows the shortwave trough along the New Mexico/Texas state line. Scattered high clouds from virga showers earlier are moving across West Texas with subtle lift ahead of the trough. The trough axis will pass over the forecast area with subsidence and northwesterly flow aloft. Weak lee troughing will develop this afternoon with mostly light south southwesterly downsloping winds across the South Plains and Rolling Plains. Pleasant weather today with sunny skies and warm temperatures in the 80s. Despite the light winds of less than 15 mph this afternoon, dry conditions (min RH values of 10 to 15 percent) will give way to elevated fire weather concerns across the far southwest Texas Panhandle and western South Plains. Areas off the Caprock will remain mild tonight with lows in the upper 50s to lower 60s as low level moisture begins to creep back into the Rolling Plains overnight. On the Caprock temperatures tonight will remain cooler in the upper 40s to lower 50s. && .LONG TERM... (Tuesday through Sunday) Issued at 330 AM CDT Mon Apr 29 2024 Flow aloft will remain zonal and fairly weak through Tuesday given a stagnant broad upper low expanding across most of ID/MT/ND. Weak return flow at the surface will gradually boost dewpoints into the upper 50s to low 60s off the Caprock during the day Tuesday with a diffuse dryline taking shape during the afternoon hours. West of the dryline, near record high temperatures are expected within downslope surface flow. While ample instability will be present for a severe storm or two over the Rolling Plains Tuesday afternoon and evening with MUCAPEs above 2000 J/kg, there appears to be very little in the way of coherent forcing for ascent with only weak convergence along the dryline and only a very minor impulse aloft. Storm coverage Tuesday is therefore currently expected to be isolated at best, with highest chances over the eastern Rolling Plains. Wednesday looks like a more favorable day for potential increased storm coverage as flow aloft begins backing and the nose of a modest southern stream jet streak lifts towards the region. There are still notable concerns regarding overall storm coverage given a continuing lack of strong forcing aloft, but increased convergence along a sharper dryline should be sufficient for isolated to scattered storms to develop during the afternoon and evening mainly along and east of I-27. Compared to Tuesday, these Wednesday storms also have a better potential of becoming severe as MUCAPEs rise above 3000 J/kg and effective shear magnitudes remain near or above 30 kt. With shear vectors roughly perpendicular to the dryline, storms Wednesday would likely remain discrete with very large hail the primary hazard. The highest threat for severe weather on Wednesday currently looks to remain over the SE TX Panhandle and Rolling Plains, although some severe threat does extend as far west as I-27 and will ultimately depend on the dryline positioning. Still a bit of uncertainty for Thursday with models still not in agreement regarding the timing of a cold front arriving from the north, as well as if any remnant dryline remains in place. Things have generally trended drier on Thursday as prefrontal surface troughing likely pushes the dryline to our east, but enough uncertainty in this still exists to maintain PoPs on Thursday afternoon mainly east of I-27 for the potential of a few additional storms. Cooler (but still near normal) temperatures then arrive Friday and persist through the weekend. The synoptic patten will generally support more widespread rain and storm chances through most of the weekend as unsettled southwest flow aloft spreads over a moist surface airmass, with some severe potential still present this weekend especially off the Caprock. && .AVIATION... (18Z TAFS) Issued at 1225 PM CDT Mon Apr 29 2024 VFR conditions will persist through this TAF period along with generally light southwest winds. Winds about 800 ft AGL will increase around sunrise tomorrow morning leading to a few hours of LLWS at all three sites before southerly surface winds increase around 14z. && .FIRE WEATHER... Issued at 330 AM CDT Mon Apr 29 2024 Warm and dry conditions this afternoon will give way to low end elevated fire weather concerns (RFTIs around 1) across the far southwest Texas Panhandle and western South Plains. Minimum relative humidity values will be around 10 to 15 percent across the aforementioned area, along with west southwest winds of 10 to 15 mph. Elevated fire weather conditions will continue mainly across the far southwest Texas Panhandle on Tuesday where minimum RH values in the high single digits and wind speeds of 15 to 20 mph will support RFTI values of 2 to 3. Elevated to potentially near-critical conditions will then return to most areas along the TX/NM state line on Wednesday as stronger southwest winds near or just above 20 mph result in RFTI values of 2 to 4. Currently, little or no fire weather concerns exist along and east of I-27/US-87 given higher humidity, better fuel moisture, and more advanced green-up. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...11 LONG TERM....30 AVIATION...58