Severe Thunderstorm Watch will be issued Soon
- Published on Monday, 11 June 2012 15:41
- David Reimer
NWS STORM PREDICTION CENTER NORMAN OK
0332 PM CDT MON JUN 11 2012
AREAS AFFECTED...W-CNTRL AND NW TX
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 112032Z - 112130Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...THE THREAT FOR LARGE HAIL AND DMGG WIND GUSTS IS
INCREASING OVER PARTS OF W-CNTRL AND NW TX. A WW WILL LIKELY BE
NEEDED WITHIN THE NEXT HR.
DISCUSSION...SFC ANALYSIS FROM 20Z PLACES A DEEPENING SFC LOW NEAR
SPS...WITH A SLOW-MOVING COLD FRONT ORIENTED SW-NE ACROSS N TX.
RECENT VISIBLE SATELLITE IMAGES SHOW INDICATIONS OF A DEVELOPING
SFC-BASED CU FIELD 40 NW MWL OCCURRING ALONG WIND SHIFT...AND
ADDITIONAL TOWERING CU DEVELOPING APPROXIMATELY 30 N SJT. VERY
STRONG BOUNDARY LAYER HEATING...WITH TEMPERATURES REACHING NEAR 100
F...HAS BEEN SUFFICIENT TO OVERCOME A WARM LAYER NEAR 850 MB
OBSERVED IN 12Z SOUNDINGS. FORCING FOR ASCENT IS EXPECTED TO BE
WEAK...BUT GIVEN THE STRONG HEATING AND CONTINUED WEAK CONVERGENCE
ALONG/NEAR WIND SHIFT AND ATTENDANT DRYLINE...INITIATION OF AT LEAST
ISOLATED STORMS APPEARS INCREASINGLY LIKELY. WITH MLCAPE VALUES NOW
EXCEEDING 4000 J/KG IN SOME AREAS...STORMS WILL LIKELY BE CAPABLE OF
PRODUCING VERY LARGE HAIL AND ISOLATED DMGG WIND GUSTS...BUT STORM
ORGANIZATION SHOULD BE SOMEWHAT LIMITED BY WEAK EFFECTIVE SHEAR
/NEAR 20 KTS/.
3 PM Severe Weather Update
- Published on Monday, 11 June 2012 15:28
- David Reimer
6/11/2012 20Z: Severe Weather Outlook
Here is the latest severe weather outlook from the Storm Prediction Center. This outlook remains nearly unchanged compared to the one we posted in our morning discussion. The orange shaded regions are in the standard risk of severe weather with a 15 percent chance of severe weather occurring within 25 miles of any given point, such as your house. Locations outside the orange zone but in the brown zone have a low risk of severe weather, or a 5 percent chance of severe weather within 25 miles of any given location, such as your house. The Dallas/Fort-Worth Metroplex is included in the standard risk of severe weather.
Visible Satellite Imagery at 3:16 PM CDT
This satellite image shows that we have the beginning development of a cumulus field from Abilene northeast to Jacksboro. This cumulus field will continue to expand over the next few hours as the cap begins to weaken. Latest short term model guidance suggests thunderstorms will be ongoing south of Abilene to around Brownwood by 6 PM. It looks like thunderstorms make take a little longer to develop northwest of Fort Worth, but all model guidance is consistent in showing thunderstorms in progress by 8 PM from Bowie to Decatur. As storms northwest of Fort Worth begin to congeal into a squall line or Mesoscale Convective System (MCS, a fancy word for a complex of storms), the risk for damaging winds would increase.
Severe Weather Risks with Strongest Storms:
Baseball or larger size hail
Damaging winds to 70 MPH (If storms congeal into line/complex, wind threat will increase and some gusts could exceed 75 MPH)
Isolated, Brief Tornadoes
Later in the evening when thunderstorms congeal into a line/complex of storms, the risk for damaging winds would increase along with a continued risk of large hail. Obviously, these storms would be prolific lightning producers.
I’m in Little Elm having lunch right now and plan to stay put for a few more hours until storms begin developing a county or two to my northwest. When that happens, I’ll move to intercept them and bring the live stream online.
12 PM Severe Weather Update
- Published on Monday, 11 June 2012 12:09
- David Reimer
[caption id="attachment_8412" align="aligncenter" width="580" caption="6/11/2012 1630Z Severe Weather Outlook"][/caption]
This graphic shows the probability of experiencing severe weather within 25 miles of any given point later this afternoon and evening. The orange color is where the Storm Prediction Center has placed a standard risk of severe weather, meaning a 15 percent chance of experiencing severe weather within 25 miles of any given point. High resolution model guidance is developing isolated thunderstorms roughly from Eastland northward to Wichita Falls by 6 PM. There is some question about how widespread storms will become due to a strong capping inversion in place, however many weather models do develop isolated thunderstorms. These thunderstorms will be isolated, but could be quite severe. In fact, it looks like instability values will support the possibility of very large hail, possibly larger then baseballs in the strongest storms.
Storms will be slowly move east (with deviant storm motions possible with left/right turning supercells). The strongest storms will likely produce hail larger then baseballs along with a secondary threat of damaging microbursts and a brief tornado possible. After a few hours, the storms may congeal into a larger complex of thunderstorms. If that occurs, the threat for a more damaging widespread wind event would increase. This is when the storms may try to move into the D/FW Metroplex. The threat of large hail would also exist with those storms. In addition, prolific amounts of cloud to ground lightning would also be likely. They would be thunderstorms after all!
I’ll be heading northwest of Fort Worth in a few hours in anticipation of intercepting storms once they develop west of D/FW. I’ll post a link to my live video stream when I activate it later this afternoon.
Severe Weather Possible in West Texas & Northeast Texas Today
- Published on Monday, 11 June 2012 01:50
- David Reimer
[caption id="attachment_8407" align="aligncenter" width="580" caption="6/11/2012 06Z Severe Weather Outlook: West Texas Severe Weather Risk"][/caption]
[caption id="attachment_8405" align="aligncenter" width="580" caption="6/11/2012 06Z Severe Weather Outlook: Northeast Texas Severe Weather Risk"][/caption]
The Storm Prediction Center has placed two separate areas in Texas under the standard risk of severe weather for Monday, June 11. Areas within the yellow shading zone have a 15 percent chance of severe weather occurring within 25 miles of any given location, like your house.
The first area is shown in graphic #1 with the southwestern panhandle and a portion of West Texas included in the standard risk. Thunderstorms will likely develop in eastern New Mexico this afternoon and push into West Texas during the early evening. That activity will be capable of producing hail up to the size of golfballs and damaging microburst winds around 60 MPH.
The second severe weather risk generally runs along and east from Gainesville to Denton, then along and north of a line from McKinney, Sulphur Springs, Mount Pleasant, to just south of Texarkana. In addition, much of Southeast Oklahoma and Arkansas is included in the standard severe weather risk. Thunderstorms will likely develop along a frontal boundary in Oklahoma and push southward. These storms or new storms that develop from their outflow could affect the Red River (generally from I-35 and points east) from 5 PM to 1 AM. While weak wind shear will limit a tornado threat, very high instability values will allow for these storms to become quite severe with hail up to the size of baseballs possible in the strongest storms. In addition, if thunderstorms are able to organized into a complex of thunderstorms the damaging wind threat would increase substantially. As I said, weak wind shear will limit the tornado threat. However, a brief tornado cannot be ruled out.
The severe weather risk will continue into Tuesday, but include much more of Northwest/North Texas. Stay tuned to our facebook/twitter pages along with our automated warning feed at www.facebook.com/TexasStormAlerts and on twitter @TexasStormAlert