Alert archive / Texas / Mesoscale Discussions in 2011
Mesoscale Discussion 689
The Storm Prediction Center issued this mesoscale discussion at May 2, 2011, 1:28 AM CDT for 4 counties in Arkansas; McCurtain County, Oklahoma; 33 counties in Texas. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- May 2, 2011, 1:28 AM CDT (06:28 UTC)
- Expired
- May 2, 2011, 4:30 AM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
All 38 counties
Howard County, AR, Little River County, AR, Miller County, AR, Sevier County, AR, McCurtain County, OK, Bosque County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Collin County, TX, Comanche County, TX, Dallas County, TX, Delta County, TX, Denton County, TX, Eastland County, TX, Ellis County, TX, Erath County, TX, Fannin County, TX, Franklin County, TX, Hamilton County, TX, Hill County, TX, Hood County, TX, Hopkins County, TX, Hunt County, TX, Johnson County, TX, Kaufman County, TX, Lamar County, TX, Morris County, TX, Parker County, TX, Rains County, TX, Red River County, TX, Rockwall County, TX, Somervell County, TX, Tarrant County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX
The radar
The Dallas/Ft Worth radar (KFWS), 151 km from the middle of the area, began a volume at 06:29 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
Fort Worth, TX (KFWD), launched 00:00Z, 6.5 hours before the alert went out and 142 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
- 538 m above ground
- 0-6 km bulk shear
- 62 kt
- 0-1 km storm-relative helicity
- 123 m²/s²
- 0-3 km storm-relative helicity
- 620 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 15.3
The text
As transmitted, in the capitals the NWS used until 2016.
094
ACUS11 KWNS 020628
SWOMCD
SPC MCD 020628
ARZ000-TXZ000-OKZ000-020930-
MESOSCALE DISCUSSION 0689
NWS STORM PREDICTION CENTER NORMAN OK
0128 AM CDT MON MAY 02 2011
AREAS AFFECTED...PORTIONS N-CENTRAL/NE TX...EXTREME SERN OK...SWRN
AR.
CONCERNING...HEAVY RAINFALL
VALID 020628Z - 020930Z
HEAVY RAINFALL THREAT...NOW GROWING FROM INCREASING COVERAGE OF
TSTMS OVER PORTIONS N TX...WILL SHIFT ENEWD ACROSS PORTIONS ARKLATEX
REGION THROUGH REMAINDER PRE-DAWN HOURS. TSTM CORES WILL BECOME
MORE NUMEROUS AND TRAIN REPEATEDLY OVER SOME LOCALES...WHILE
OFFERING PRECIP RATES 1-2 INCHES/HOUR.
EXPECT ADVECTION OF MOISTURE-RICH AIR MASS -- I.E. PW GENERALLY IN
1-1.5 INCH RANGE -- TO SUPPORT CONTINUED INCREASE IN TSTM COVERAGE
FOR ANOTHER COUPE OF HOURS OVER CENTRAL/N-CENTRAL TX...SHIFTING
ENEWD TOWARD ARKLATEX REGION BEFORE 12Z. PLUME OF MOISTURE
TRANSPORT WILL BE ASSOCIATED WITH 35-45 KT LLJ INTERACTING WITH COLD
FRONTAL ZONE AT AND ABOVE 850-MB LEVEL...WITH COMBINATION OF
FRONTAL/ISENTROPIC ASCENT TO LFC. ACTIVITY WILL BE SUPPORTED
INITIALLY BY NRN FRINGE OF FIELD OF 1000-2000 J/KG MUCAPE...ALTHOUGH
INCREASING CONVECTIVE DENSITY AND WEAKENING OF
ELEVATED/STORM-RELATIVE LOW-LEVEL FLOW VECTORS WILL REDUCE
REPLENISHMENT OF BUOYANCY BY WAA WITH TIME. AFTER ABOUT 09Z...WRN
BRANCH OF LLJ IS EXPECTED TO VEER AND WEAKEN SOMEWHAT...BUT WILL
SUPPORT CONTINUE PLUME OF MOISTURE TRANSPORT AND ELEVATED/ISENTROPIC
ASCENT FOR CONVECTION SHIFTING DOWNSHEAR ACROSS THIS CORRIDOR.
REF SPC MESOSCALE DISCUSSION 688 FOR COVERAGE OF SHORTER-TERM SVR
HAIL THREAT OVER WRN PORTIONS OF THIS AREA.
..EDWARDS.. 05/02/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LZK...SHV...TSA...FWD...OUN...SJT...
LAT...LON 33409352 32649488 31409828 32119919 33069784 34189514
34379403 33409352SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 1, 7:31 PM CDT | Mesoscale Discussion | SPC | Clay, Cleburne, Conway, Craighead, Faulkner, Garland and 20 more | 59 min |
| May 1, 8:10 PM CDT | Mesoscale Discussion | SPC | Arkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 24 more | 35 min |
| May 2, 1:51 PM CDT | Mesoscale Discussion | SPC | Ashley, Chicot, Desha, Drew | 2 hr |
| May 2, 12:55 AM CDT | Mesoscale Discussion | SPC | Bryan, Choctaw | 3 hr |
Nearby
Mesoscale Discussions in Texas, 2011Mesoscale Discussions in Arkansas, 2011Mesoscale Discussions in Oklahoma, 2011Every mesoscale discussion in 2011
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.