394 FXUS64 KSJT 221730 AFDSJT Area Forecast Discussion National Weather Service San Angelo TX 1130 AM CST Tue Jan 22 2019 .AVIATION... /18Z TAFS/ Latest satellite imagery shows the low level clouds continuing to dissipate and the mid level clouds moving off to the east with clear skies beginning to move into the western portions of the area. All terminals will transition to VFR conditions over the next few hours. Winds will shift to the west and turn breezy as a weak surface low moves across the area. A cold front will move south across the region and bring another wind shift. The front will move through the terminals from 21z through 03z. Winds will be from the northwest at 20 to 25 knots with isolated gusts up to 30 knots possible. Behind the front, dry air filters in and skies will turn clear and the winds will drop to less than 10 knots. && .PREV DISCUSSION... /issued 555 AM CST Tue Jan 22 2019/ AVIATION... /12Z TAFS/ The main aviation weather concerns are with low clouds and MVFR ceilings early this morning, and with gusty winds today and early tonight. Low cloud cover is expanding to the northwest across much of our area early this morning, and will affect most if not all of our TAF sites with MVFR ceilings. Expect a quick breakup of low clouds by mid-to-late morning. Gusty south winds early this morning will decrease to some extent in the 13Z to 16Z time frame. Winds will veer to the west toward midday and continue into this afternoon, ahead of an approaching cold front. Wind speeds will increase again toward midday, and gusty west winds are expected this afternoon. Winds will shift to the north-northwest later this afternoon and evening, with passage of a cold front. Expected timing of the cold frontal passage is: 23Z at KABI, 00Z- 01Z at KSJT and KBBD, and 02Z-03Z at KSOA and KJCT. Following the cold frontal passage, gusty north-northwest winds early tonight will decrease to 6-10 knots overnight. PREV DISCUSSION... /issued 412 AM CST Tue Jan 22 2019/ SHORT TERM... (Today and Tonight) An upper trough, currently extending from the northern Plains south- southwest into New Mexico and Arizona, will shift east today and tonight. By late tonight, the trough axis will extend from the Midwest south-southwest across West Texas. For our area, gusty south winds early this morning will veer to the west by this afternoon, ahead of a cold front. The cold front will advance south across our northern counties (Big Country area) during the afternoon. This cold front will quickly push south through our central counties this evening, and should be south of our forecast area by 9 PM. Within the overall gusty wind regime, the stronger winds (near advisory criteria at times) are occurring across the Big Country and Concho Valley areas early this morning (south winds prior to sunrise). The stronger winds will affect these same areas this afternoon around 2-4 PM (west winds), and for a 2-3 hour period immediately following the cold frontal passage (north-northwest winds). With the segmented nature of the stronger winds, not planning to issue a wind advisory at this time. This is something we will monitor, however. The high temperature forecast is a bit tricky today, with timing of the cold front across our northern counties, and extent of high cloud coverage this afternoon. Temperatures should drop off after the frontal passage in the far northern part of our area. With westerly downsloping component to the winds this afternoon ahead of the front, some of the numerical guidance hints at highs near 70 at San Angelo, and 70-73 across the southeastern part of our area. Believe that morning low cloud cover and enough afternoon high cloud cover will not allow temperatures to get quite that warm. Going with highs ranging from near 60 across our far north/northwest counties, to near 70 in our far southeastern counties. Overnight lows are expected to be in the upper 20s to lower 30s, with the colder readings across the northwestern part of our area. Gust north- northwest winds early tonight will decrease to 8-12 mph overnight. Keeping PoPs below 15 percent in our far southeastern counties. A few showers may develop this afternoon just outside of our area in parts of the Hill Country, as a surface trough enters that area. Advection of much drier air will occur after winds shift to the west. Fire weather concerns are addressed in a separate section. 19 LONG TERM... (Wednesday through next Monday) The general thinking for the next several days has not changed significantly over the past 24 hours. An active pattern will send periodic cold fronts through the area, resulting in temperatures swinging back and forth around our normal values for the next week. Wednesday will be near or below normal following Tuesday's cold frontal passage. Warmer temperatures and breezy conditions will follow on Thursday afternoon. Models have sped up the timing of the next front, actually bringing it through Thursday afternoon and evening, which will result in colder temperatures Thursday night and Friday. Moisture begins to quickly return Friday night ahead of a shortwave that models are bringing from the Arizona area southeast into northern Mexico on Saturday. This will actually bring a chance of showers, and possibly isolated thunderstorms Saturday afternoon and evening, mainly for the eastern half of the area. Following those rain chances, we have another day of breezy southwest winds, and slightly warmer temperatures on Sunday before the next cold front moves into the area to start the work week. 20 FIRE WEATHER... Elevated fire weather conditions are expected for a few hours this afternoon, mainly between 2 PM and 5 PM, across much of the Concho Valley and Northern Edwards Plateau. The primary area of concern encompasses Sterling, Coke, Tom Green, Irion, Crockett and Schleicher Counties. West winds (20 ft) at 15-20 mph will be combined with relative humidity values 25-30 percent and temperatures in the mid 60s. Winds will shift to the north- northwest with a cold frontal passage this evening. Although winds will remain gusty after the frontal passage, relative humidity values will climb quickly as temperatures drop. 19 && .PRELIMINARY POINT TEMPS/POPS... Abilene 30 49 34 54 / 0 0 0 0 San Angelo 31 53 32 58 / 0 0 0 0 Junction 32 54 31 62 / 10 0 0 0 Brownwood 32 50 30 58 / 0 0 0 0 Sweetwater 29 50 34 53 / 0 0 0 0 Ozona 32 52 31 58 / 0 0 0 0 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ 99/99/40