Alert archive / Florida / Mesoscale Discussions in 2017

Mesoscale Discussion 962

June 7, 201712 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Jun 7, 2017, 12:48 PM EDT for 12 counties in Florida. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jun 7, 2017, 12:48 PM EDT (16:48 UTC)
Expired
Jun 7, 2017, 3:15 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Charlotte County, FL, Collier County, FL, DeSoto County, FL, Glades County, FL, Hendry County, FL, Highlands County, FL, Indian River County, FL, Lee County, FL, Martin County, FL, Okeechobee County, FL, Palm Beach County, FL, Saint Lucie County, FL

The radar

The Melbourne radar (KMLB), 129 km from the middle of the area, began a volume at 16:49 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

Cape Canaveral, FL (KXMR), launched 12:00Z, 4.8 hours before the alert went out and 170 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, Cape Canaveral, FL at 12:00Z on 2017-06-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 358 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, Cape Canaveral, FL at 12:00Z on 2017-06-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 124 square meters per square second.19395878Sfc1 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
358 J/kg
Mixed-layer CIN
-97 J/kg
Mixed-layer LCL
697 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
124 m²/s²
0-3 km storm-relative helicity
155 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.6

Open this sounding in Storm Lab

The text

As transmitted.

509 
ACUS11 KWNS 071648
SWOMCD
SPC MCD 071648 
FLZ000-071915-

Mesoscale Discussion 0962
NWS Storm Prediction Center Norman OK
1148 AM CDT Wed Jun 07 2017

Areas affected...South-central Florida Peninsula

Concerning...Severe potential...Watch unlikely 

Valid 071648Z - 071915Z

Probability of Watch Issuance...20 percent

SUMMARY...A marginal wind damage threat should continue this
afternoon across the south-central Florida Peninsula. A brief
tornado can not be ruled out as well. Weather watch issuance is not
expected but the situation will continue to be monitored.

DISCUSSION...The latest surface analysis shows a 1005 mb low over
the northeastward Gulf of Mexico. A moist airmass is in place from
the low southeastward across the Florida Peninsula where surface
dewpoints are mostly in the lower 70s F. A band of strong
thunderstorms is ongoing across the central Florida Peninsula. Ahead
of this band, a narrow corridor of warmer surface temperatures is
present and the RAP is estimating MLCAPE values in the 1000 to 1500
J/kg range. In addition, WSR-88D VWPs at Tampa Bay and Melbourne
show 0-6 km shear in the 35 to 40 kt range with mostly
unidirectional wind profiles. This should continue to support a line
segment as it moves across the south-central Florida Peninsula. A
marginal wind damage threat should exist with bowing structures
embedded in the line. Although low-level shear is not that strong, a
brief tornado may also occur if a cell within the line can develop
rotation.

..Broyles/Guyer.. 06/07/2017

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

ATTN...WFO...MFL...MLB...TBW...

LAT...LON   26608011 26937993 27568018 28058040 28138081 27308171
            26778226 26138198 25638106 26608011

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 6, 10:13 PM EDTMesoscale DiscussionSPCMiami-Dade3 hr

Nearby

Mesoscale Discussions in Florida, 2017Every mesoscale discussion in 2017

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.