Alert archive / Arkansas / Mesoscale Discussions in 2012
Mesoscale Discussion 1748
The Storm Prediction Center issued this mesoscale discussion at Aug 12, 2012, 10:26 PM CDT for 11 counties in Arkansas; 6 counties in Oklahoma; 7 counties in Texas. It was in force for 94 min.
The area
The outline as issued.
The facts
- Issued
- Aug 12, 2012, 10:26 PM CDT (03:26 UTC)
- Expired
- Aug 13, 2012, 12:00 AM CDT
- In force
- 94 min
- Issued by
- the Storm Prediction Center
All 24 counties
Crawford County, AR, Franklin County, AR, Howard County, AR, Little River County, AR, Logan County, AR, Montgomery County, AR, Polk County, AR, Scott County, AR, Sebastian County, AR, Sevier County, AR, Yell County, AR, Adair County, OK, Haskell County, OK, LeFlore County, OK, McCurtain County, OK, Muskogee County, OK, Sequoyah County, OK, Bowie County, TX, Camp County, TX, Cass County, TX, Franklin County, TX, Hopkins County, TX, Morris County, TX, Titus County, TX
The radar
The Western Arkansas radar (KSRX), 129 km from the middle of the area, began a volume at 03:26 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Shreveport, LA (KBAD), launched 00:00Z, 3.4 hours before the alert went out and 220 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
- 2046 J/kg
- Mixed-layer CIN
- -3 J/kg
- Mixed-layer LCL
- 1830 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 50 m²/s²
- 0-3 km storm-relative helicity
- 93 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.6
The text
As transmitted, in the capitals the NWS used until 2016.
157
ACUS11 KWNS 130327
SWOMCD
SPC MCD 130326
ARZ000-TXZ000-OKZ000-130500-
MESOSCALE DISCUSSION 1748
NWS STORM PREDICTION CENTER NORMAN OK
1026 PM CDT SUN AUG 12 2012
AREAS AFFECTED...ERN OK THROUGH NERN TX AND WRN THROUGH CNTRL AR
CONCERNING...SEVERE THUNDERSTORM WATCH 574...
VALID 130326Z - 130500Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 574
CONTINUES.
SUMMARY...A THREAT FOR ISOLATED DAMAGING WIND AND LARGE HAIL WILL
PERSIST MAINLY OVER NERN TX AND ECNTRL AND NERN OK NEXT COUPLE
HOURS. OTHER STORMS ARE INCREASING OVER WCNTRL AND NWRN ARKANSAS.
SOME OF THESE STORMS COULD ALSO BECOME CAPABLE OF PRODUCING ISOLATED
STRONG WIND GUSTS AND HAIL...BUT ANY WW ISSUANCE IN ARKANSAS WILL
ULTIMATELY DEPEND ON CONVECTIVE TRENDS.
DISCUSSION...CONVECTION THAT DEVELOPED EARLIER THIS EVENING IN SERN
OK PRODUCED AN EXPANSIVE OUTFLOW BOUNDARY. STORMS ARE FORWARD
PROPAGATING SEWD THROUGH NERN TX ALONG THIS BOUNDARY AND MAY
CONTINUE TO POSE A THREAT FOR ISOLATED DAMAGING WIND NEXT COUPLE
HOURS. FARTHER NORTH ACROSS ECNTRL OK...OTHER STORMS HAVE DEVELOPED
ALONG NRN EXTENSION OF THE OUTFLOW BOUNDARY. ACTIVITY REMAINS
EMBEDDED WITHIN 30-35 KT EFFECTIVE SHEAR THAT WILL SUPPORT UPDRAFT
ROTATION AND A THREAT FOR ISOLATED LARGE HAIL AND DAMAGING WIND
GUSTS.
OTHER STORMS ARE INCREASING OVER WRN ARKANSAS IN ASSOCIATION WITH
ISENTROPIC ASCENT AUGMENTED BY DEVELOPING SWLY LLJ. MODIFIED POINT
FORECAST SOUNDINGS SUGGEST THESE STORMS ARE LIKELY ELEVATED AND
ROOTED BETWEEN 800 AND 750 MB. ACTIVITY IS DEVELOPING WITHIN
MODERATE MUCAPE...BUT WITH EFFECTIVE SHEAR AOB 30 KT. A FEW OF THESE
STORMS MIGHT ALSO BECOME CAPABLE OF PRODUCING ISOLATED HAIL AND
LOCALLY STRONG WIND GUSTS NEXT COUPLE HOURS.
..DIAL.. 08/13/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LZK...SHV...TSA...FWD...
LAT...LON 34819496 35069575 35699544 36069445 34759288 34149393
32809444 32759522 33009595 33329595 33419480 34819496SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 12, 10:49 PM CDT | Severe Thunderstorm Watch | SPC | Benton, Boone, Carroll, Conway, Crawford, Franklin and 16 more | 5 hr |
| Aug 13, 1:45 AM CDT | Mesoscale Discussion | SPC | Arkansas, Baxter, Benton, Boone, Carroll, Cleburne and 36 more | 2 hr |
| Aug 13, 7:48 AM CDT | Mesoscale Discussion | SPC | Ashley, Bradley, Chicot, Cleveland, Desha, Drew | 87 min |
| Aug 13, 3:15 PM CDT | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Chicot, Crittenden, Cross and 9 more | 30 min |
| Aug 13, 3:32 PM CDT | Severe Thunderstorm Watch | SPC | Arkansas, Chicot, Crittenden, Cross, Desha, Drew and 7 more | 7 hr |
| Aug 12, 7:16 PM CDT | Severe Thunderstorm Watch | SPC | Adair, Cherokee, Choctaw, Haskell, Latimer, LeFlore and 6 more | 4 hr |
| Aug 12, 8:41 PM CDT | Mesoscale Discussion | SPC | Bryan, Choctaw, Pushmataha | 64 min |
Nearby
Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Oklahoma, 2012Every mesoscale discussion in 2012
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.