Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 105
The Storm Prediction Center issued this mesoscale discussion at Feb 16, 2021, 9:41 PM CST for 11 counties in Texas. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 16, 2021, 9:41 PM CST (03:41 UTC)
- Expired
- Feb 17, 2021, 1:45 AM CST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Winter mixed precipitation
Counties Bell County, TX, Brazos County, TX, Burleson County, TX, Burnet County, TX, Falls County, TX, Lampasas County, TX, Leon County, TX, Llano County, TX, Milam County, TX, Robertson County, TX, Williamson County, TX
The nearest sounding before it
Fort Worth, TX (KFWD), launched 00:00Z, 3.7 hours before the alert went out and 233 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1371 m above ground
- 0-6 km bulk shear
- 83 kt
- 0-1 km storm-relative helicity
- 231 m²/s²
- 0-3 km storm-relative helicity
- 314 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
601
ACUS11 KWNS 170342
SWOMCD
SPC MCD 170341
TXZ000-170745-
Mesoscale Discussion 0105
NWS Storm Prediction Center Norman OK
0941 PM CST Tue Feb 16 2021
Areas affected...Parts of central Texas
Concerning...Winter mixed precipitation
Valid 170341Z - 170745Z
SUMMARY...Light to occasionally moderate precipitation will
overspread parts of central Texas, roughly between Austin, Waco and
College Station through Midnight-3 AM CST. This may initiate as
sleet in most areas, before changing over to freezing rain with
accumulating ice probable on most exposed surfaces.
DISCUSSION...A developing band of precipitation now spreading
east-northeast of the Edwards Plateau appears largely forced by
lower/mid tropospheric frontogenetic forcing, Models suggest that
this will be maintained across parts of central Texas (particularly
near/northwest of Austin into areas between Waco and College
Station) into and through the 06-09Z time frame, although there may
be some fluctuations in intensity.
Based on forecast soundings, lift appears generally maximized within
the dendritic growth zone, but temperatures above freezing within
the 850-700 mb layer are allowing for falling precipitation to melt.
East-north of the Edwards Plateau, cooling within this initially
unsaturated layer, due to melting and evaporation, may support
relatively minor accumulations of sleet. However, as elevated warm
advection continues across the region on south-southwesterly flow,
warming and deepening of the warm layer is expected to allow for a
changeover to rain.
Although rain rates may remain relatively light to occasionally
moderate in intensity, with surface temperatures mostly in the upper
teens to mid 20s F, ice may quickly accumulate on most exposed
surfaces.
..Kerr.. 02/17/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...HGX...FWD...EWX...SJT...
LAT...LON 30519882 30979895 31269862 31429699 31359599 30579601
30289782 30269870 30519882SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 16, 6:59 PM CST | Mesoscale Discussion | SPC | Armstrong, Briscoe, Carson, Castro, Childress, Collingsworth and 7 more | 4 hr |
| Feb 16, 8:14 PM CST | Mesoscale Discussion | SPC | Archer, Clay, Cooke, Grayson, Jack, Montague and 2 more | 4 hr |
| Feb 17, 1:55 AM CST | Mesoscale Discussion | SPC | Angelina, Austin, Bastrop, Brazos, Burleson, Colorado and 31 more | 6 hr |
| Feb 17, 7:38 AM CST | Mesoscale Discussion | SPC | Jasper, Newton, Sabine | 4 hr |
| Feb 17, 9:15 AM CST | Mesoscale Discussion | SPC | Bowie, Cass | 6 hr |
Nearby
Mesoscale Discussions in Texas, 2021Every mesoscale discussion in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.