Area Forecast Discussion
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Issued by NWS
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726 FXUS64 KLUB 010818 AFDLUB Area Forecast Discussion National Weather Service Lubbock TX 318 AM CDT Wed May 1 2024 ...New SHORT TERM, LONG TERM, FIRE WEATHER... .SHORT TERM... (Today and tonight) Issued at 311 AM CDT Wed May 1 2024 In classic West Texas fashion, the first day of May should hit the ground running with dryline storms later today and especially by this evening. Early morning water vapor imagery showed gravity waves rolling west over the region courtesy of two MCSs in OK, but otherwise our W-SW flow aloft was devoid of any meaningful features. This will change later this morning as SW winds aloft pick up some steam ahead of an elongated trough overspreading the Intermountain West. At the surface meanwhile, a dryline roughly from Dora-Dimmitt- Amarillo at 2 AM is expected to retreat another 60 miles or so ahead of increasingly moist southerlies and eventually some low clouds by daybreak. Eastward mixing of the dryline this afternoon doesn`t appear particularly aggressive thanks to the deepening moisture and more importantly a diffuse surface low drifting from eastern NM into southeast CO by this evening. By peak heating, most high res guidance paints the dryline along a line from Silverton southwest to Lubbock and Brownfield which seems reasonable. East of the dryline, MLCAPEs should soar to 2500-3500 J/kg with modest CIN overall and 30-35 knots of deep layer shear. Marginal CIN and poor anvil-level SR flow would tend to favor a shorter window for supercells early on, before ample DCAPE near the dryline raises the chances of storm modes becoming increasingly messy and linear. On that note, several models (CAMs and globals) depict a H7 trough currently along the Sierra Madres that lifts northeast through the day before triggering dryline storms over the western Permian Basin around 21Z and growing quickly upscale thereafter. Given large DCAPE along the dryline and straight hodographs, there is a growing signal from CAMs that this initially supercellular convection could be quite efficient with downbursts and more importantly left movers that race north and into our southern South Plains this evening complete with damaging winds and blowing dust. Past events such as this often accelerate the dryline`s evening retreat and expand chances for additional storms. NBM`s westward extent of PoPs on the Caprock look good for this setup, but its values were raised considerably off the Caprock by this evening as a linear MCS is likely to evolve with wind and heavy rain the greatest threats. A second and more conditional area for storm initiation later today could involve an outflow boundary currently loitering over our northeastern counties from nocturnal storms in southwest OK. This boundary appears rather diffuse overall and will more than likely wash out through the day given how much modification will ensue in the next 12+ hours. Convection should depart our eastern zones toward midnight all the while the dryline returns to NM and a cold front works its way south across the western TX Panhandle. NBM temps today and tonight needed no change. && .LONG TERM... (Thursday through Tuesday) Issued at 311 AM CDT Wed May 1 2024 A generally quieter weather day is expected on Thursday as an early- day cold front passes southward through the region. The front itself will not be particularly strong or quick-moving as upstream pressure rises remain modest and deepening surface troughing over eastern NM and the Permian Basin slow its southward progression. Even behind the front temperatures will still warm well into the 80s with the more notable post-frontal change being a reduction in near-surface moisture and relative lack of cloud cover given the drier upstream airmass. Some models still depict isolated convection on Thursday in the vicinity of a remnant dryline, but this should be well to our east and will therefore carry a dry forecast over the entire forecast area Thursday through early Friday. Guidance is in good agreement that low level moisture will increase once again beginning on Friday as surface flow obtains a stronger easterly component, which will also result in high temperatures falling back near seasonal averages. Thunderstorm potential on Friday is a bit more unclear as some models hint at scattered storms firing within the moist upslope regime, but large-scale forcing will still be quite weak with only a very modest midlevel wave progged to approach the region during the evening with inhibition also appearing fairly significant due to a strong capping inversion. Still, the uncertainty and increased moisture does support maintaining low PoPs off the Caprock Friday afternoon and evening. An additional cold front will pass through the region on Saturday, with flow aloft also progged to strengthen through the day as well. A majority of model guidance still points to the late Saturday through early Sunday period as most favorable for potential widespread rainfall as a more significant upper level disturbance transits overhead within the stronger southwest flow aloft. Specifics are uncertain at this range, but ensemble consensus suggests that most of the region has a good chance (50-80%) of receiving one tenth of an inch of rain or more over the weekend. Early next week, a much deeper upper trough is progged to develop over the western CONUS, but at this point its projected evolution would bring a return of dry and breezy conditions to our area Monday through Tuesday. && .AVIATION... (06Z TAFS) Issued at 1233 AM CDT Wed May 1 2024 Following some LLWS at PVW and CDS overnight, moistening southerly winds may fuel some IFR-MVFR stratus development near LBB and CDS around sunrise. Confidence remains iffy in the coverage and duration of these ceilings. Similar confidence exists regarding impacts from TS late in the afternoon as a dryline stalls near PVW and LBB. Later TAFs will better address this potential as newer data arrive. && .FIRE WEATHER... Issued at 311 AM CDT Wed May 1 2024 Dry and breezy conditions are likely this afternoon across the far southwest Texas Panhandle and northwest South Plains behind a dryline. Fuels in these areas are more receptive to fire spread and when combined with southwest winds of 15 to 20 mph and RHs falling to around 10 percent, a Rangeland Fire Danger statement is justified for Parmer and Bailey Counties from 1 PM until 8 PM. Farther east, thunderstorms (some severe) will increase in coverage by this evening with heavy rainfall possible off the Caprock. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...93 LONG TERM....30 AVIATION...93