Alert archive / Mississippi / Mesoscale Discussions in 2004

Mesoscale Discussion 285

April 7, 20044 states

The Storm Prediction Center issued this mesoscale discussion at Apr 7, 2004, 5:06 PM CDT for 4 states. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Apr 7, 2004, 5:06 PM CDT (22:06 UTC)
Expired: Apr 7, 2004, 7:00 PM CDT
In force: 114 min
Issued by: the Storm Prediction Center

Counties Baldwin County, AL, Mobile County, AL, Escambia County, FL, Plaquemines Parish, LA, Saint Bernard Parish, LA, George County, MS, Harrison County, MS, Jackson County, MS

The radar

The Mobile radar (KMOB), 77 km from the middle of the area, began a volume at 22:09 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

Slidell Radar S, LA (KSIL), launched 12:00Z, 10.1 hours before the alert went out and 99 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: 39 J/kg
Mixed-layer CIN: -161 J/kg
Mixed-layer LCL: 652 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 89 m²/s²
0-3 km storm-relative helicity: 105 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.

518 
ACUS11 KWNS 072207
SWOMCD
SPC MCD 072206 
ALZ000-FLZ000-MSZ000-LAZ000-080000-

MESOSCALE DISCUSSION 0285
NWS STORM PREDICTION CENTER NORMAN OK
0506 PM CDT WED APR 07 2004

AREAS AFFECTED...COASTAL SE LA / EXTREME SERN MS / SRN AL / WRN FL
PANHANDLE

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 072206Z - 080000Z

ISOLATED SEVERE STORMS WITH THE POTENTIAL FOR A BRIEF TORNADO...WILL
REMAIN POSSIBLE THROUGH EARLY EVENING. A WW IS NOT ANTICIPATED AS
MOST OF THE ACTIVITY IS EXPECTED TO REMAIN OFFSHORE.

LATEST SURFACE ANALYSIS SHOWS E-W WARM FRONTAL ZONE ALONG THE
COASTAL AREAS OF MS AND AL WITH DEWPOINTS IN THE UPPER 60S ALONG AND
S OF THIS BOUNDARY.  WARM FRONT HAS MOVED ASHORE WITH NARROW SECTOR
OF MID/UPPER 60S F DEWPOINTS NOW OVER SRN MS.  WINDS OVER MOST OF LA
AND SW MS HAVE VEERED TO WLY WITHIN HIGH SURFACE THETA PLUME WHERE
TEMPERATURES ARE IN THE 80S F. STORMS WILL CONTINUE TO DEVELOP IN
THIS AREA AS LARGE SCALE HEIGHT FALLS CONTINUE ALONG WITH LOW LEVEL
CONVERGENCE NEAR WARM FRONT.

MODIFIED FORECAST SOUNDINGS YIELD 1500-2000 MLCAPE WHILE VWPS SHOW
SUFFICIENT DEEP LAYER SHEAR FOR A FEW SEVERE STORMS. BACKED SURFACE
WINDS ALONG WARM FRONT AND LOW LCL HEIGHTS COULD FAVOR THE
DEVELOPMENT OF ISOLATED WATERSPOUTS AND/OR TORNADOES.  MODIFIED
2136Z MOB VWP YIELDS 80-100 M2/S2 OF 0-1 KM SRH...AND SRM DATA HAS
SHOWN SIGNS OF ROTATION.

STORMS N OF WARM FRONT IN MORE STABLE AIR MASS WITH LOWER 60S
DEWPOINTS WILL HAVE LESS OF A CHANCE OF ROTATION BUT COULD PRODUCE
AN ISOLATED HAIL REPORT.

..JEWELL.. 04/07/2004

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

ATTN...WFO...MOB...LIX...

29258962 29608967 29848958 30138950 30408915 30768884
31318830 31368809 31288776 31008748 30278700 30118755
30038839 29818869 29378886 29058900 29128928

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 7, 4:47 PM CDT	Mesoscale Discussion	SPC	Greene, Pickens, Sumter	28 min
Apr 7, 6:50 PM CDT	Severe Thunderstorm Watch	SPC	Autauga, Butler, Chilton, Choctaw, Clarke, Conecuh and 11 more	5 hr
Apr 7, 2:24 PM CDT	Mesoscale Discussion	SPC	Bay, Calhoun, Gulf	96 min
Apr 7, 12:58 PM CDT	Mesoscale Discussion	SPC	Bienville, Bossier, Caddo, Claiborne, De Soto, Lincoln and 4 more	2 hr
Apr 7, 2:45 PM CDT	Severe Thunderstorm Watch	SPC	Bossier, Caddo, Claiborne, De Soto, Red River, Webster	5 hr
Apr 7, 6:08 PM CDT	Mesoscale Discussion	SPC	Allen, Avoyelles, Beauregard, Bienville, Bossier, Caddo and 27 more	67 min
Apr 7, 5:10 PM CDT	Severe Thunderstorm Watch	SPC	Attala, Bolivar, Carroll, Choctaw, Clay, Grenada and 20 more	6 hr

Nearby

Mesoscale Discussions in Mississippi, 2004 Mesoscale Discussions in Alabama, 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.