Alert archive / Florida / Mesoscale Discussions in 2024
Mesoscale Discussion 1821
The Storm Prediction Center issued this mesoscale discussion at Aug 5, 2024, 5:09 AM EDT for 14 counties in Florida. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- Aug 5, 2024, 5:09 AM EDT (09:09 UTC)
- Expired
- Aug 5, 2024, 6:45 AM EDT
- In force
- 96 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 595
Counties Alachua County, FL, Citrus County, FL, Gilchrist County, FL, Hardee County, FL, Hernando County, FL, Hillsborough County, FL, Lake County, FL, Levy County, FL, Manatee County, FL, Marion County, FL, Pasco County, FL, Polk County, FL, Sarasota County, FL, Sumter County, FL
The radar
The Tampa radar (KTBW), 103 km from the middle of the area, began a volume at 09:13 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
Tampa Bay, FL (KTBW), launched 00:00Z, 9.2 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.
- Mixed-layer CAPE
- 881 J/kg
- Mixed-layer CIN
- -1 J/kg
- Mixed-layer LCL
- 467 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 500 m²/s²
- 0-3 km storm-relative helicity
- 550 m²/s²
- Significant tornado parameter
- 1.8
- Supercell composite
- 12.4
The text
As transmitted.
467
ACUS11 KWNS 050909
SWOMCD
SPC MCD 050909
FLZ000-051045-
Mesoscale Discussion 1821
NWS Storm Prediction Center Norman OK
0409 AM CDT Mon Aug 05 2024
Areas affected...west-central to north FL
Concerning...Tornado Watch 595...
Valid 050909Z - 051045Z
The severe weather threat for Tornado Watch 595 continues.
SUMMARY...Threat for a couple tornadoes should primarily be confined
to the west-central Florida Peninsula through sunrise, but should
increase later this morning across parts of central and north
Florida. Replacement of WW 595 is expected before its 10Z
expiration.
DISCUSSION...Transient rotation within outer-band thunderstorms has
largely been confined to the west-central FL Peninsula over the past
several hours. This near-term threat is roughly centered from
Sarasota to western Lake counties, largely south through northeast
of Tampa Bay. The 06Z TBW sounding sampled a favorable environment
for a couple tornadoes, characterized by MLCAPE near 1000 J/kg amid
0-1 km SRH of 150-200 m2/s2.
As limited diabatic surface heating occurs after sunrise beneath the
extensive cloud canopy surrounding slow-moving Debby, a gradual
boost to MLCAPE should occur farther north and inland. Recent CAM
guidance suggests potential for intermediate banded structures to
reform north of the Tampa Bay area as this occurs, which would yield
a larger spatial extent of the tornado threat. The east-central/
northeast coast of the peninsula will likely have a near-term nil
threat owing to meager MLCAPE of about 250 J/kg per the 06Z JAX/XMR
soundings, and may struggle to appreciably increase until late
morning if an outer band can separately form off the east coast and
spread inland. CAM guidance suggests this may tend to focus from the
FL/GA border northward later this morning.
..Grams/Edwards.. 08/05/2024
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MLB...TBW...JAX...TAE...
LAT...LON 29268304 29848299 30038265 30048230 29688178 29188156
28458142 27888150 27398168 26948211 27088242 27348258
28388281 29268304SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 4, 10:11 PM EDT | Mesoscale Discussion | SPC | Alachua, Baker, Bradford, Citrus, Clay, Columbia and 22 more | 2 hr |
| Aug 5, 12:31 AM EDT | Mesoscale Discussion | SPC | Alachua, Baker, Bradford, Citrus, Clay, Columbia and 17 more | 119 min |
| Aug 5, 5:57 AM EDT | Tornado Watch | SPC | Alachua, Baker, Bradford, Citrus, Clay, Columbia and 23 more | 12 hr |
| Aug 5, 12:08 PM EDT | Mesoscale Discussion | SPC | Alachua, Baker, Bradford, Charlotte, Citrus, Clay and 23 more | 52 min |
Nearby
Mesoscale Discussions in Florida, 2024Every mesoscale discussion in 2024
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.