Alert archive / Florida / Mesoscale Discussions in 2024

Mesoscale Discussion 2139

October 9, 2024Broward County, Hendry County, Palm Beach County, Florida

The Storm Prediction Center issued this mesoscale discussion at Oct 9, 2024, 12:35 PM EDT for Broward County, Hendry County, Palm Beach County, Florida. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
Oct 9, 2024, 12:35 PM EDT (16:35 UTC)
Expired
Oct 9, 2024, 2:00 PM EDT
In force
85 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 690

Counties Broward County, FL, Hendry County, FL, Palm Beach County, FL

The radar

The Miami radar (KAMX), 84 km from the middle of the area, began a volume at 16:34 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

Miami, FL (KMFL), launched 12:00Z, 4.6 hours before the alert went out and 67 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, Miami, FL at 12:00Z on 2024-10-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1797 joules per kilogram.LCLEL10008507005003002001001 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, Miami, FL at 12:00Z on 2024-10-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 192 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
1797 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
686 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
192 m²/s²
0-3 km storm-relative helicity
255 m²/s²
Significant tornado parameter
1.1
Supercell composite
9.2

Open this sounding in Storm Lab

The text

As transmitted.

993 
ACUS11 KWNS 091635
SWOMCD
SPC MCD 091635 
FLZ000-091800-

Mesoscale Discussion 2139
NWS Storm Prediction Center Norman OK
1135 AM CDT Wed Oct 09 2024

Areas affected...Portions of South Florida

Concerning...Tornado Watch 690...

Valid 091635Z - 091800Z

The severe weather threat for Tornado Watch 690 continues.

SUMMARY...Tornadoes remain possible south of Lake Okeechobee with
developing/deepening updrafts.

DISCUSSION...Temperatures in South Florida have risen into the upper
80s to near 90 F. Several updrafts have began to develop and deepen
south of Lake Okeechobee per local radar ZDR data. Should these
updrafts sufficiently deepen, they will be capable of producing
tornadoes as the low-level flow is only expected to intensify
through the day as Hurricane Milton continues east and its wind
field expands. The greatest potential will be with storms closer to
the eastern coast as cloud cover has been less abundant. Further,
low-level winds are more backed with northward extent which will
increase tornado potential there as well.

..Wendt.. 10/09/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MFL...

LAT...LON   26538027 26248035 26008042 25588068 25618087 26398132
            26788102 26938057 26878033 26538027

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 9, 12:31 AM EDTMesoscale DiscussionSPCMonroe89 min
Oct 9, 5:45 AM EDTMesoscale DiscussionSPCBroward, Charlotte, Collier, Glades, Hendry, Lee and 4 more4 hr
Oct 9, 8:20 AM EDTTornado WatchSPCBrevard, Broward, Charlotte, Collier, DeSoto, Glades and 24 more13 hr
Oct 9, 10:19 AM EDTMesoscale DiscussionSPCBroward, Collier, Hendry, Palm Beach86 min
Oct 9, 11:12 AM EDTMesoscale DiscussionSPCCharlotte, Lee93 min
Oct 9, 11:50 AM EDTMesoscale DiscussionSPCGlades, Hendry, Highlands, Indian River, Martin, Okeechobee and 3 more115 min
Oct 9, 1:13 PM EDTMesoscale DiscussionSPCCharlotte, Collier, DeSoto, Lee, Manatee, Sarasota92 min
Oct 9, 1:51 PM EDTMesoscale DiscussionSPCBrevard, Indian River, Martin, Okeechobee, Orange, Osceola and 2 more84 min
Oct 9, 2:49 PM EDTMesoscale DiscussionSPCBrevard, Broward, Indian River, Martin, Okeechobee, Osceola and 3 more86 min
Oct 9, 4:15 PM EDTMesoscale DiscussionSPCBrevard, Broward, Indian River, Martin, Okeechobee, Osceola and 2 more90 min
Oct 9, 6:22 PM EDTMesoscale DiscussionSPCBrevard, Glades, Hardee, Hendry, Hernando, Highlands and 14 more113 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.