Alert archive / Florida / Mesoscale Discussions in 2003

Mesoscale Discussion 449

April 8, 200315 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Apr 8, 2003, 4:51 PM EDT for 15 counties in Florida. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Apr 8, 2003, 4:51 PM EDT (20:51 UTC)
Expired: Apr 8, 2003, 6:45 PM EDT
In force: 114 min
Issued by: the Storm Prediction Center

Counties Alachua County, FL, Bradford County, FL, Clay County, FL, Dixie County, FL, Flagler County, FL, Franklin County, FL, Gilchrist County, FL, Gulf County, FL, Lafayette County, FL, Levy County, FL, Marion County, FL, Putnam County, FL, Saint Johns County, FL, Taylor County, FL, Union County, FL

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 8.9 hours before the alert went out and 103 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: 38 J/kg
Mixed-layer CIN: -151 J/kg
Mixed-layer LCL: 688 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 87 m²/s²
0-3 km storm-relative helicity: 244 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.8

Open this sounding in Storm Lab

The text

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

296 
ACUS11 KWNS 082052
SWOMCD
SPC MCD 082051 
FLZ000-082245-

MESOSCALE DISCUSSION 0449
NWS STORM PREDICTION CENTER NORMAN OK
0351 PM CDT TUE APR 08 2003

AREAS AFFECTED...PORTIONS NRN FL...SRN GA

CONCERNING...SEVERE THUNDERSTORM WATCH 117...

VALID 082051Z - 082245Z

WIDELY SCATTERED TSTMS IN CLUSTERS CONTINUE MOVING NNEWD ACROSS
WW AREA...WITH SEPARATE CONVECTIVE LINE APPROACHING FROM W. 
REDUCED CONVERGENCE INDICATED OVER REGION ALONG AND S OF FRONT
BECAUSE OF VEERED BOUNDARY LAYER FLOW -- ESPECIALLY W OF I-75 --
WHICH APPEARS TO BE LIMITING CONVECTIVE INTENSITY FOR NOW. 
HOWEVER...TWO PRIMARY FACTORS INDICATE WW SHOULD BE CONTINUED FOR
TIME BEING... 
1. INFLOW LAYER AIR MASS WILL REMAIN FAVORABLY UNSTABLE ANOTHER
COUPLE HOURS WITH MID 60S/LOW 70S F SFC DEW POINTS CONTRIBUTING
TO MLCAPE NEAR 2000 J/KG
2. WEAK MESOLOW EVIDENT OFFSHORE AQQ...NEAR LINE OF NONSEVERE
CONVECTION NOW MOVING EWD TOWARD NRN FL...MAY CONTRIBUTE ENOUGH
ISALLOBARIC FORCING TO BACK FLOW AND ENHANCE WHAT IS NOW MARGINAL
VERTICAL SHEAR.


..EDWARDS.. 04/08/2003

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

ATTN...WFO...MLB...TBW...JAX...TAE...

30088565 30088365 30188246 30338137 29238106 28828273
29628530

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 7, 9:13 PM EDT	Mesoscale Discussion	SPC	Calhoun, Escambia, Gadsden, Jackson, Okaloosa, Santa Rosa and 2 more	62 min
Apr 8, 11:32 AM EDT	Mesoscale Discussion	SPC	Alachua, Bradford, Clay, Dixie, Flagler, Franklin and 9 more	3 hr
Apr 8, 1:00 PM EDT	Severe Thunderstorm Watch	SPC	Alachua, Baker, Bradford, Clay, Columbia, Dixie and 15 more	5 hr
Apr 8, 2:32 PM EDT	Mesoscale Discussion	SPC	Alachua, Bradford, Clay, Dixie, Flagler, Franklin and 9 more	118 min

Nearby

Mesoscale Discussions in Florida, 2003 Every mesoscale discussion in 2003

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.