Alert archive / Texas / Mesoscale Discussions in 2018
Mesoscale Discussion 1012
The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2018, 3:18 PM CDT for 19 counties in Texas. It was in force for 57 min.
The area
The outline as issued.
The facts
- Issued
- Jul 4, 2018, 3:18 PM CDT (20:18 UTC)
- Expired
- Jul 4, 2018, 4:15 PM CDT
- In force
- 57 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
Counties Bandera County, TX, Bastrop County, TX, Bexar County, TX, Blanco County, TX, Burnet County, TX, Caldwell County, TX, Comal County, TX, Gillespie County, TX, Gonzales County, TX, Guadalupe County, TX, Hays County, TX, Kendall County, TX, Kerr County, TX, Llano County, TX, Mason County, TX, Medina County, TX, Travis County, TX, Williamson County, TX, Wilson County, TX
The radar
The Austin/San Antonio radar (KEWX), 48 km from the middle of the area, began a volume at 20:18 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Del Rio, TX (KDLF), launched 12:00Z, 8.3 hours before the alert went out and 267 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
- 1850 J/kg
- Mixed-layer CIN
- -64 J/kg
- Mixed-layer LCL
- 904 m above ground
- 0-6 km bulk shear
- 8 kt
- 0-1 km storm-relative helicity
- -76 m²/s²
- 0-3 km storm-relative helicity
- 10 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
862
ACUS11 KWNS 042018
SWOMCD
SPC MCD 042018
TXZ000-042115-
Mesoscale Discussion 1012
NWS Storm Prediction Center Norman OK
0318 PM CDT Wed Jul 04 2018
Areas affected...portions of central Texas
Concerning...Severe potential...Watch unlikely
Valid 042018Z - 042115Z
Probability of Watch Issuance...20 percent
SUMMARY...Isolated damaging wind gusts are possible with
intensifying storms across the region. A WW issuance is not
anticipated at this time.
DISCUSSION...Scattered thunderstorms continue to increase across the
region just downstream of a tropical mid/upper low centered near
CLL. Stout surface heating has resulted in areas of weak to
moderate instability (500-2000 J/kg MUCAPE) and steep low-level
lapse rates just ahead of these storms. Meanwhile, maturing cold
pools beneath ongoing convection were resulting in a few strong wind
gusts (47 kts recently reported at Austin within the past 45
minutes). These trends should continue through the early evening -
especially if storms can congeal into linear segments that could
propagate west-southwestward amidst 30-kt northeasterly 700mb flow.
Isolated damaging wind gusts are possible with this activity, and a
brief spinup or two may also occur if updrafts can interact
favorably with low-level boundaries across the region. These
threats should remain too isolated to necessitate a WW issuance.
..Cook.. 07/04/2018
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FWD...EWX...SJT...
LAT...LON 30619709 30939766 31039847 30849910 30409964 29919980
29189943 28909857 29119761 29649708 30119698 30619709Nearby
Mesoscale Discussions in Texas, 2018Every mesoscale discussion in 2018
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; radar from the NEXRAD Level II archive.