Alert archive / Texas / Mesoscale Discussions in 2004

Mesoscale Discussion 2521

December 8, 20045 parishes in Louisiana; 9 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at Dec 8, 2004, 5:47 PM CST for 5 parishes in Louisiana; 9 counties in Texas. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Dec 8, 2004, 5:47 PM CST (23:47 UTC)
Expired: Dec 8, 2004, 7:15 PM CST
In force: 88 min
Issued by: the Storm Prediction Center

Counties Acadia Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Jefferson Davis Parish, LA, Vermilion Parish, LA, Brazoria County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Hardin County, TX, Harris County, TX, Jefferson County, TX, Liberty County, TX, Orange County, TX

The radar

The Houston radar (KHGX), 94 km from the middle of the area, began a volume at 23:50 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 11.8 hours before the alert went out and 102 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 2129 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 170 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

706 
ACUS11 KWNS 082348
SWOMCD
SPC MCD 082347 
LAZ000-TXZ000-090115-

MESOSCALE DISCUSSION 2521
NWS STORM PREDICTION CENTER NORMAN OK
0547 PM CST WED DEC 08 2004

AREAS AFFECTED...UPPER TX COAST INTO SWRN LA

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 082347Z - 090115Z

ISOLATED SEVERE WEATHER THREAT IS EXPECTED TO INCREASE ACROSS
DISCUSSION AREA THIS EVENING. CONVECTIVE TRENDS WILL BE MONITORED
FOR POSSIBLE OUTLOOK UPGRADE AND WW ISSUANCE.

23Z MESOANALYSIS INDICATES PRIMARY WARM FRONT ACROSS THE NWRN GULF
FROM NEAR BRO NEWD TO APPROXIMATELY 30-40 NM OFF GALVESTON BAY TO
JUST OFF THE SERN LA COAST. DEWPOINTS IN THE UPPER 60S TO LOWER 70S
COUPLED WITH MID-LEVEL LAPSE RATES OF AROUND 7 C/KM ARE CONTRIBUTING
TO MLCAPES OF 1000-2000 J/KG S OF THIS BOUNDARY OVER THE NWRN GULF
OF MEXICO. WITH APPROACH OF SHORTWAVE TROUGH CURRENTLY MOVING ACROSS
WRN TX...EXPECT THIS BOUNDARY TO LIFT NWD...ALLOWING FOR THIS
SURFACE-BASED INSTABILITY TO DEVELOP ALONG THE UPPER TX COAST INTO
SWRN LA. FORECAST HODOGRAPHS SUGGEST THAT WIND FIELDS ALONG COAST
WILL REMAIN SUPPORTIVE OF ORGANIZED TSTMS...INCLUDING THE
POSSIBILITY SUPERCELLS. DAMAGING WINDS AND A BRIEF TORNADO OR TWO
WILL BE POSSIBLE WITH ANY SURFACE-BASED STORMS...WHILE ELEVATED
DEVELOPMENT N OF BOUNDARY WILL BE CAPABLE OF MAINLY MARGINAL HAIL.

..MEAD.. 12/08/2004

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

ATTN...WFO...LCH...HGX...

28969622 29869560 30519432 30639311 30599228 30039198
29569225 29459386 28689569

Nearby

Mesoscale Discussions in Texas, 2004 Mesoscale Discussions in Louisiana, 2004 Every mesoscale discussion in 2004

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.