Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX
Issued by NWS Austin/San Antonio, TX
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
057 FXUS64 KEWX 080827 AFDEWX Area Forecast Discussion National Weather Service Austin/San Antonio TX 327 AM CDT Wed May 8 2024 ...New SHORT TERM, LONG TERM... .SHORT TERM... (Today through Thursday) Issued at 236 AM CDT Wed May 8 2024 Temperatures will warm to well above normal today across all of south central Texas with highs ranging from 100 to 105 degrees along the Rio Grande with 90s elsewhere. Our current forecast calls for 103 degrees at Del Rio, which would tie the existing high temperature record. Heat Index values across our coastal plains counties may briefly approach 108 degrees in a few spots this afternoon. We will opt to issue a Special Weather Statement for our coastal plains counties from Atascosa eastward to Lavaca county to cover the elevated heat index values today. With this heat coming a little early in the season, it will be important to practice heat safety precautions today. The other item of concern for today is the potential for isolated storms to develop across portions of the Hill Country into the nearby I-35 corridor, mainly from Burnet county eastward into Williamson county. Forecast soundings generally show the mid-level capping inversion will remain strong today thus limiting the potential for storms to develop. In addition, models keep a fair amount of high clouds today and this may limit heating as the dryline mixes eastward. If storms manage to break the cap, they would likely be severe given adequate shear and impressive instability. We will keep some low pops in the forecast, but below mentionable values. If 12Z guidance trends weaker with the cap, the forecast will need to be updated to mention thunderstorm chances over portions of the Hill Country and adjacent I-35 corridor. The dryline retreats westward tonight keeping most of the region in a warm and humid air mass. Expect warm overnight lows in the upper 60s to upper 70s. On Thursday, the pattern is expected to become active as the dryline mixes eastward during the afternoon and interacts with a cold front moving southward across north Texas. Daytime heating along with some weak upper disturbances embedded in the southwest flow aloft should be enough to initiate convection in the vicinity of the dryline and front intersection, with hi-res guidance favoring initial development across San Saba/Mason/Llano counties during the late afternoon. Convection will then likely continue to develop along the southward moving cold front across the remainder of the Hill Country and I-35 counties, mainly near/north of San Antonio through the early evening hours. Large to very large hail and damaging winds are the main severe weather concerns. SPC has upgraded the severe threat to Enhanced (level 3 of 5) for areas along and north of a Llano to Austin line. The Slight to Marginal risk areas extends farther south to near a Rocksprings to San Antonio to Hallettsville line. It will be very warm again on Thursday, especially out west along the Rio Grande behind the dryline where highs of 103 to 106 degrees are forecast. The record high for Del Rio will likely be met or exceeded. We will need to keep an eye on San Antonio as well, but will likely end up a couple degrees shy of the record. Austin looks safe as record highs were set back in the heat wave of 2011. && .LONG TERM... (Thursday night through Tuesday) Issued at 236 AM CDT Wed May 8 2024 Synopsis: On Thursday night, storms should have come to an end, but it`s possible some lingering strong to severe storms may still be around after sunset Thursday. An upper level low situated over the Four Corners will remain in place through the first half of the weekend, eventually ejecting out over the southern Plains on Sunday. Once this storm system moves out over the Plains, we should see some drier and warmer weather return by the beginning to middle of next week. Thursday Night-Friday: A strong cold front by early May standards will move through South Central Texas Thursday night, bringing cooler and drier air into the region after several abnormally hot and humid days. Winds may be quite gusty at times, but a wind advisory is not expected. Winds will remain northeasterly through the day Friday, keeping temperatures some 5-10 degrees below normal for early May, and falling some 10-20 degrees from highs on Wednesday and Thursday. Saturday-Sunday: The upper-level trough ejects out over the southern CONUS late Saturday, and with easterly surface flow resulting in rapid moistening of the overall atmospheric profile, showers and thunderstorms are expected to develop late Saturday and persist through Sunday afternoon before moving eastward by Monday afternoon. Sunday will likely be the coolest day of the week, with highs in the lower 70s over the Hill Country and portions of the I-35 corridor. As far as the severe threat goes, severe storms are not anticipated, however, continue to monitor the forecast over the next several days for any possible changes. Monday-Wednesday: A steady warming trend is expected as we edge closer to normal highs for early to mid May. Uncertainty in the overall upper-level pattern will lead to low end PoPs through the remainder of the long term period. && .AVIATION... (00Z TAFS) Issued at 627 PM CDT Tue May 7 2024 VFR conditions continue until around 04-05Z at I-35 sites and around 08Z at DRT. Low stratus will develop again tonight into Wednesday morning with MVFR to IFR ceilings expected. Some models develop LIFR conditions near SAT/SSF, but using persistence opted to keep this potential out of the forecast. Areas of fog will also be possible, particularly over portions of the southern Edwards Plateau and western Hill Country. Ceilings will first lift at DRT as a dryline moves over the western half of the area in the morning, eventually lifting in the east during the early afternoon. South to southeasterly wind continues through morning at all sites before winds shift from the northwest at DRT around 13Z. After 18Z the eastern half of the area will see modest west to southwesterly flow. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 93 74 90 68 / 0 0 30 10 Austin Bergstrom Intl Airport 91 73 90 68 / 0 0 30 10 New Braunfels Muni Airport 95 73 93 69 / 10 0 20 10 Burnet Muni Airport 91 70 87 65 / 10 0 30 10 Del Rio Intl Airport 104 72 106 72 / 0 0 0 10 Georgetown Muni Airport 90 72 88 66 / 10 0 30 10 Hondo Muni Airport 98 70 98 69 / 0 0 10 0 San Marcos Muni Airport 92 72 91 68 / 0 0 20 10 La Grange - Fayette Regional 91 74 90 70 / 0 10 20 10 San Antonio Intl Airport 95 74 94 70 / 0 0 10 10 Stinson Muni Airport 97 74 95 71 / 0 0 10 10 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...Platt Long-Term...MMM Aviation...Platt