Alert archive

Mesoscale Discussion 798

May 12, 2012

The Storm Prediction Center issued this mesoscale discussion at May 12, 2012, 5:22 PM CDT. It was in force for 23 min.

The area

The outline as issued.

The facts

Issued
May 12, 2012, 5:22 PM CDT (22:22 UTC)
Expired
May 12, 2012, 5:45 PM CDT
In force
23 min
Issued by
the Storm Prediction Center
Chance of a watch
5%

The radar

The Brownsville radar (KBRO), 47 km from the middle of the area, began a volume at 22:21 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

Brownsville Intl, TX (KBRO), launched 12:00Z, 10.4 hours before the alert went out and 49 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.

Skew-T log-pSkew-T log-p diagram, Brownsville Intl, TX at 12:00Z on 2012-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3455 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brownsville Intl, TX at 12:00Z on 2012-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
3455 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
477 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
9 m²/s²
Significant tornado parameter
0.3
Supercell composite
1.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

797 
ACUS11 KWNS 122222
SWOMCD
SPC MCD 122222 
TXZ000-122245-

MESOSCALE DISCUSSION 0798
NWS STORM PREDICTION CENTER NORMAN OK
0522 PM CDT SAT MAY 12 2012

AREAS AFFECTED...A SMALL PART OF DEEP SOUTH TX

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 122222Z - 122245Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...SVR THREAT WILL REACH THE RIO GRANDE RIVER DURING THE NEXT
HALF HOUR...AFFECTING CAMERON/HIDALGO COUNTIES. SVR THREAT WILL BE
TOO ISOLATED FOR A WW.

DISCUSSION...SUPERCELL STRUCTURES WILL PROPAGATE SWD TO THE RIO
GRANDE RIVER AMIDST STRONG BUOYANCY/STEEP LOW-LEVEL LAPSE RATES.
RADAR CROSS SECTIONS SUGGEST A STRONG SIGNAL THAT SVR HAIL/WIND MAY
EVOLVE FROM THESE STORMS AS THEY APPROACH THE INTERNATIONAL BORDER
/REF. BWER STRUCTURE AND ECHO OVERHANG OVER CAMERON COUNTY/.

..COHEN/WEISS.. 05/12/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...BRO...

LAT...LON   26019783 26049817 26229814 26249775 26139754 26039761
            26019783

Nearby

Every 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.