Alert archive / Florida / Mesoscale Discussions in 2003

Mesoscale Discussion 577

April 25, 200321 counties in Florida; 12 counties in Georgia; Beaufort County, South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 25, 2003, 1:01 PM EDT for 21 counties in Florida; 12 counties in Georgia; Beaufort County, South Carolina. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued
Apr 25, 2003, 1:01 PM EDT (17:01 UTC)
Expired
Apr 25, 2003, 3:00 PM EDT
In force
119 min
Issued by
the Storm Prediction Center
All 34 counties

Alachua County, FL, Baker County, FL, Bradford County, FL, Citrus County, FL, Clay County, FL, Columbia County, FL, Dixie County, FL, Duval County, FL, Flagler County, FL, Gilchrist County, FL, Hernando County, FL, Lake County, FL, Levy County, FL, Marion County, FL, Nassau County, FL, Pasco County, FL, Putnam County, FL, Saint Johns County, FL, Sumter County, FL, Union County, FL, Volusia County, FL, Brantley County, GA, Bryan County, GA, Camden County, GA, Charlton County, GA, Chatham County, GA, Glynn County, GA, Liberty County, GA, Long County, GA, McIntosh County, GA, Pierce County, GA, Ware County, GA, Wayne County, GA, Beaufort County, SC

The radar

The Jacksonville radar (KJAX), 49 km from the middle of the area, began a volume at 17:00 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Jacksonville, FL (KJAX), launched 12:00Z, 5.0 hours before the alert went out and 51 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, Jacksonville, FL at 12:00Z on 2003-04-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 109 joules per kilogram.LCLLFCEL10008507005003002001001 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, Jacksonville, FL at 12:00Z on 2003-04-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 174 square meters per square second.193958Sfc1 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
109 J/kg
Mixed-layer CIN
-260 J/kg
Mixed-layer LCL
1059 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
174 m²/s²
0-3 km storm-relative helicity
283 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

878 
ACUS11 KWNS 251702
SWOMCD
SPC MCD 251701 
FLZ000-SCZ000-GAZ000-251900-

MESOSCALE DISCUSSION 0577
NWS STORM PREDICTION CENTER NORMAN OK
1201 PM CDT FRI APR 25 2003

AREAS AFFECTED...SE GA...NRN FL...PARTS OF CNTRL FL PEN

CONCERNING...SEVERE THUNDERSTORM WATCH 164...

VALID 251701Z - 251900Z

NEW WW MAY BE NEEDED SOUTH OF WW 164 WITHIN NEXT COUPLE OF HOURS.

MORNING SOUNDINGS AND LATEST MODEL PROGS HAVE SUGGESTED SUFFICIENTLY
LOW RELATIVE HUMIDITIES IN LOWER/MID-LEVELS TO ENHANCE EVAPORATIVE
COOLING IN DOWNDRAFTS ACROSS SOUTHERN GEORGIA/NORTHERN FLORIDA. 
EVOLVING SURFACE COLD POOL APPEARS TO BE STRENGTHENING...
PARTICULARLY WITH SURFACE TEMPERATURES HEATING INTO THE 80S AHEAD OF
SQUALL LINE ACROSS NORTHERN FLORIDA AND NORTHERN PORTIONS OF THE
PENINSULA.  MODELS SUGGEST 30 KT SOUTHERLY LOW-LEVEL JET EXTENDS AS
FAR SOUTH AS THE TAMPA/MELBOURNE AREAS BY LATE AFTERNOON...WITH
DOWNWARD TRANSFER OF THIS MOMENTUM ENHANCING POTENTIAL FOR DAMAGING
WIND GUSTS.

..KERR.. 04/25/2003

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

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

29028099 28388173 28268250 28538268 

29538341 30048300 30568284 31268251 31998162 32388101
32388053

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 25, 4:05 AM EDTMesoscale DiscussionSPCEscambia85 min
Apr 25, 6:40 AM EDTMesoscale DiscussionSPCBay, Calhoun, Escambia, Holmes, Jackson, Okaloosa and 3 more65 min
Apr 25, 7:05 AM EDTTornado WatchSPCBay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 7 more6 hr
Apr 25, 8:41 AM EDTMesoscale DiscussionSPCBay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 6 more94 min
Apr 25, 10:22 AM EDTMesoscale DiscussionSPCGadsden, Hamilton, Jefferson, Leon, Liberty, Madison and 1 more113 min
Apr 25, 11:45 AM EDTSevere Thunderstorm WatchSPCBaker, Columbia, Hamilton, Jefferson, Lafayette, Madison and 3 more5 hr
Apr 25, 2:15 PM EDTSevere Thunderstorm WatchSPCAlachua, Bradford, Citrus, Clay, Duval, Flagler and 10 more5 hr
Apr 25, 3:17 PM EDTMesoscale DiscussionSPCAlachua, Bradford, Citrus, Clay, Duval, Flagler and 10 more118 min
Apr 25, 6:35 PM EDTMesoscale DiscussionSPCCitrus, Hernando, Lake, Orange, Pasco, Seminole and 2 more55 min
Apr 25, 1:45 PM EDTTornado WatchSPCCatoosa, Chattooga, Dade, Floyd, Walker5 hr
Apr 25, 4:08 PM EDTMesoscale DiscussionSPCCarroll, Chattahoochee, Clayton, Cobb, Coweta, Douglas and 17 more2 hr
Apr 25, 6:00 PM EDTTornado WatchSPCBarrow, Bartow, Bibb, Butts, Carroll, Catoosa and 51 more5 hr

Nearby

Mesoscale Discussions in Florida, 2003Mesoscale Discussions in Georgia, 2003Mesoscale Discussions in South Carolina, 2003Every 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; radar from the NEXRAD Level II archive.