Area Forecast Discussion
Issued by NWS San Angelo, TX

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172 FXUS64 KSJT 221759 AFDSJT Area Forecast Discussion National Weather Service San Angelo TX 1259 PM CDT Sun Sep 22 2024 ...New AVIATION... .SHORT TERM... (Today and tonight) Issued at 342 AM CDT Sun Sep 22 2024 ...Thunderstorms expected this afternoon through tonight... Currently, an upper level low is located over CO, with southwest flow over west central Texas. This low is expected to open into a wave while slowly moving east into the central and southern plains by Monday morning. This will maintain southwesterly flow over our area. At the surface, a cold front is expected to move south into our CWA by this afternoon, making its way through the rest of the area by late tonight. Scattered to widespread thunderstorms are expected to develop along and ahead of the cold front this afternoon, and continue through most of the overnight hours. With temperatures warming well into the 80s to lower 90s this afternoon, combined with plentiful low level moisture (precipitable water values near 2 inches), low levels will destabilize ahead of the front. Mixed layer CAPE values are forecast to be in the 500 to 1500 J/kg range during peak heating hours. Deep layer shear values of 40 to 50 knots over the area, combined with the instability will allow some of the storms to become strong, with a few storms possibly severe. The main concern with the storms will be wind gusts over 60 mph, but hail up to the size of quarters will also be possible. After sunset, instability will wane, and although storms may continue, the concern for severe weather will diminish. The other concern will be heavy rain and localized flooding with precipitable water values near 2 inches. Storms are expected to develop first over the Big Country along the front, then spread southward over the rest of the area during the afternoon and overnight hours as the front moves south. Overall coverage should diminish late tonight, but isolated to scattered activity will still be possible after midnight, mainly south of Interstate 20. && .LONG TERM... (Monday through Saturday) Issued at 449 AM CDT Sun Sep 22 2024 An upper level low pressure system will move north of our area and then proceed east across the Plains on Monday. Then, another strong low pressure system will move across the eastern portions of the Great Plains on Wednesday. This will swing another cold front into the area, which will keep temperatures a bit cooler for the remainder of the work week. High temperatures look to be in the upper 70s to middle 80s. This same system and the attendant frontal boundary will also be supportive of another round of rainfall across the area on Tuesday and Wednesday ahead of the front. The Weather Prediction Center has placed west Central Texas into another Marginal Risk (5% chance) of excessive rainfall leading to flash flooding on Tuesday and Tuesday night. Rainfall totals may be near 0.5" to 1" during this time frame with locally higher amounts remaining possible. We will have to keep an eye on this scenario for changes in the next day or two. && .AVIATION...
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(18Z TAFS) Issued at 1256 PM CDT Sun Sep 22 2024 Ceilings have lifted to VFR across the terminals early this afternoon. Still expecting a cold front to move south across the terminals late this afternoon and evening, with FROPA at KABI around 22Z, KSJT around 00Z and the far southern terminals by mid to late evening. Showers and thunderstorms are expected to develop along and behind the front, and will include TEMPO groups for TS this forecast cycle. Precipitation is expected to end across the far southern terminals by mid to late morning tomorrow. Also, ceilings are expected to lower to IFR overnight, and persist through at least the mid morning hours.
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&& .PRELIMINARY POINT TEMPS/POPS...
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Abilene 59 75 62 85 / 80 30 40 40 San Angelo 62 76 64 86 / 80 40 30 30 Junction 66 82 66 88 / 40 40 10 30 Brownwood 64 78 64 85 / 60 40 30 40 Sweetwater 59 75 63 85 / 70 20 30 40 Ozona 63 77 65 86 / 70 40 20 20 Brady 64 78 65 85 / 50 40 30 30
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&& .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...20 LONG TERM....41 AVIATION...24