Alert archive / Florida / Mesoscale Discussions in 2012

Mesoscale Discussion 1365

July 2, 201221 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Jul 2, 2012, 6:42 PM EDT for 21 counties in Florida. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 2, 2012, 6:42 PM EDT (22:42 UTC)
Expired
Jul 2, 2012, 8:45 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%
All 21 counties

Alachua County, FL, Bay County, FL, Bradford County, FL, Calhoun County, FL, Clay County, FL, Dixie County, FL, Flagler County, FL, Franklin County, FL, Gilchrist County, FL, Gulf County, FL, Lafayette County, FL, Lake County, FL, Levy County, FL, Liberty County, FL, Marion County, FL, Putnam County, FL, Sumter County, FL, Taylor County, FL, Union County, FL, Volusia County, FL, Wakulla County, FL

The radar

The Tallahassee radar (KTLH), 120 km from the middle of the area, began a volume at 22:44 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

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 10.7 hours before the alert went out and 118 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, Tallahassee Rgnl, FL at 12:00Z on 2012-07-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 879 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, Tallahassee Rgnl, FL at 12:00Z on 2012-07-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -47 square meters per square second.1939Sfc1 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
879 J/kg
Mixed-layer CIN
-184 J/kg
Mixed-layer LCL
1104 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
-47 m²/s²
0-3 km storm-relative helicity
-44 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.

000 
ACUS11 KWNS 022242
SWOMCD
SPC MCD 022242 
FLZ000-030045-

MESOSCALE DISCUSSION 1365
NWS STORM PREDICTION CENTER NORMAN OK
0542 PM CDT MON JUL 02 2012

AREAS AFFECTED...NRN FL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 022242Z - 030045Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...AN ISOLATED THREAT FOR SVR STORMS WILL CONTINUE THROUGH
EARLY EVENING. A WW IS NOT NEEDED.

DISCUSSION...VISIBLE SATELLITE/RADAR IMAGERY SUGGEST CONVECTION
COLOCATED WITH A SFC CONFLUENCE AXIS LYING FROM NEAR TALLAHASSEE
FL...TO NEAR GAINESVILLE FL...TO 40 WNW DAYTONA BEACH FL WHERE IT
INTERSECTS A WWD-MOVING SEA BREEZE CONVERGENCE ZONE. THE COVERAGE OF
CONVECTION/GREATEST THREAT FOR STRONG-SVR STORMS WILL BE HIGHEST
OVER THE NRN FL PENINSULA IN THE BROAD VICINITY OF THE INTERSECTION
POINT...WHERE LOW-LEVEL ASCENT WILL BE MAXIMIZED. MORE ISOLATED
ACTIVITY IS ANTICIPATED FARTHER WEST INTO THE FL PANHANDLE NEAR THE
CONFLUENCE AXIS AND ALONG RELATIVELY A MORE ILL-DEFINED SEA BREEZE
CONVERGENCE AXIS PER VISIBLE SATELLITE IMAGERY. MLCAPE VALUES OF
1500-2500 J/KG WILL SUPPORT VIGOROUS CONVECTIVE UPDRAFTS...WITH
MARGINALLY SVR HAIL POSSIBLE...ALONG WITH SPORADIC MICROBURSTS
POTENTIALLY CONTAINING MARGINALLY SVR WIND GUSTS AIDED BY
PRECIPITATION LOADING PROCESSES GIVEN PW OF 1.75-2.00 INCHES PER GPS
DATA. WEAK TROPOSPHERIC FLOW AND THE ABSENCE OF STRONGER FORCING FOR
ASCENT WILL KEEP CONVECTION LARGELY DISORGANIZED. STORM
COVERAGE/INTENSITY SHOULD WANE AFTER 00Z AS THE NOCTURNAL BOUNDARY
LAYER GROWS.

..COHEN/HART.. 07/02/2012

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

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

LAT...LON   30118181 29958150 29408110 29098101 28758116 28608188
            28808254 29338312 29868371 30008396 29978426 29688477
            29618525 29998558 30088561 30368536 30458510 30488444
            30328356 30038293 30058242 30118181

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 1, 11:33 PM EDTMesoscale DiscussionSPCAlachua, Baker, Bay, Bradford, Calhoun, Clay and 20 more117 min

Nearby

Mesoscale Discussions in Florida, 2012Every 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.