Note: This article was written in advance of last week’s severe storm threat in central Texas. Some communities ended up seeing 60-80 mph wind gusts leading to wind damage, and also quarter to nearly ping pong ball size hail (1.5″ in diameter). For storm/damage photos, click here.
AUSTIN (KXAN) — The 7 a.m. Friday update from the NOAA Storm Prediction Center continues the “enhanced risk” for severe storms (a 3 out of 5 on the threat scale) for much of central Texas including Austin, and now also includes more of the Hill Country. This diagnosis means that numerous severe thunderstorms are possible.
As the storm approaches, we are pouring over new forecast data and honing in on which specific threats are most likely for our area.
The storm threats depend a bit on how much the clouds break — and thus how much temperatures heat up — this afternoon before the front arrives. Assuming we get some breaks of sun in the Hill Country warming temperatures into the upper 70s, we will be able to tap into atmospheric instability and fire a few discrete supercell thunderstorms. If these form, very large hail and a tornado would be the main threats.
Since the supercell development is still conditional on afternoon temperatures, the tornado threat is a bit more uncertain today and thus lower on your threat scale.
As the storms form into a more certain squall line and approach the Austin metro by 6-7 p.m. then race eastward; strong, damaging wind gusts of 75+ mph and large hail are the more sizable threats. The threat of tornadoes drops a bit once the storms form into a line, but small tornadoes can still form embedded within the line.
The NOAA Storm Prediction Center issues daily severe weather threat maps, with the different colors of shading relate to how widespread their forecasters expect severe weather to be. Today’s “enhanced risk” means that numerous severe storms are possible.
Separately, the NOAA SPC issues a black, hatched area on some severe weather risk days, indicating the threat of “significant severe” storms.
The “significant severe” forecast by the NOAA SPC relates not only to storm coverage, but also to their potential intensity.
Today, parts of our area including Austin are included in both the “significant hail” threat and the “significant wind” threat, meaning storms may produce hail 2″ in diameter (egg-sized) and damaging wind gusts of 75+ mph.
It should be noted that central Texas is not included in the threat of “significant tornadoes” (EF-2+ intensity), but some areas in northeast Texas are.
Tornadoes are not common in the winter but have occurred in the Austin metro area in every month of the year. Here are the entries from our weather diary on March 8, 2016:
“EF-0 TORNADO AT 9:17 AM NEAR CR248/RR2338 IN NW WILLIAMSON CO. 80 MPH WINDS, 50 YDS. WIDE, ON THE GROUND FOR 1.5 MILES NEAR ANDICE AREA, WITH MINOR DAMAGE TO TREES, OUTBUILDINGS, AND A FEW HOMES. EF-1 TORNADO TOUCHES DOWN AT 7:10 PM, 3E OF KATEMCY, TRAVELS 2 MI. IN N. MASON CO., LIFTING 4W FREDONIA. 185 YDS WIDE, 95-100 MPH WINDS. MAINLY TREE DAMAGE. TORNADO ALSO REPORTED 5NE FREDONIA IN SW SAN SABA CO. Tornado Warnings in the morning for Lampasas and Williamson County. Damage to private marina and trees on Lake Buchanan near Tow. Waterspout (likley gustnado) seen over Lake Buchanan. Otherwise scattered showers and thunderstorms in the morning, then more storms develop during the late afternoon. Golf ball hail N. Lampasas Co. Tornado Warnings in the evening for San Saba, Mason counties as large supercell moves across the area. Grapefruit size hail between Katemcy and Fredonia. 2″ hail 7 WSW Katemcy. Golf ball hail 10 N of Mason. Funnel cloud 16 W of Cherokee. Spotters also see wall cloud, possible rain-wrapped tornado near Fredonia. Quarter size hail and 2″ of rain in 2 hours in San Saba. Rain, thunderstorms weaken late, but continue slowly spreading, developing eastward, into metro area before midnight.”– KXAN Weather Diary
The last time Austin was included in this threat of significant thunderstorm winds was June 16, 2019, a day that brought 57 mph wind gusts to Georgetown.
Austin was last in the threat of significant hail on June 17, 2019, but no severe hail was observed from that day’s storms. Prior to that, a significant hail threat on April 17, 2019 did yield 1-inch diameter hail (quarter-sized) in Richland Springs, San Saba County.