Alert archive / Florida / Mesoscale Discussions in 2017

Mesoscale Discussion 95

January 21, 201710 counties in Florida

The Storm Prediction Center issued this mesoscale discussion at Jan 21, 2017, 5:05 PM CST for 10 counties in Florida. It was in force for 55 min.

The area

The outline as issued.

The facts

Issued
Jan 21, 2017, 5:05 PM CST (23:05 UTC)
Expired
Jan 21, 2017, 6:00 PM CST
In force
55 min
Issued by
the Storm Prediction Center

Counties Bay County, FL, Calhoun County, FL, Franklin County, FL, Gulf County, FL, Jefferson County, FL, Leon County, FL, Liberty County, FL, Wakulla County, FL, Walton County, FL, Washington County, FL

The radar

The Tallahassee radar (KTLH), 72 km from the middle of the area, began a volume at 23:07 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

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 11.1 hours before the alert went out and 75 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 2017-01-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 352 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 2017-01-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 139 square meters per square second.1939587897117Sfc1 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
352 J/kg
Mixed-layer CIN
-14 J/kg
Mixed-layer LCL
613 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
139 m²/s²
0-3 km storm-relative helicity
217 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.0

Open this sounding in Storm Lab

The text

As transmitted.

412 
ACUS11 KWNS 212305
SWOMCD
SPC MCD 212305 
FLZ000-GAZ000-220000-

Mesoscale Discussion 0095
NWS Storm Prediction Center Norman OK
0505 PM CST Sat Jan 21 2017

Areas affected...Portions of the Florida Panhandle

Concerning...Tornado Watch 14...

Valid 212305Z - 220000Z

The severe weather threat for Tornado Watch 14 continues.

SUMMARY...Limited severe/tornado risk lingers across remaining
portions of Tornado Watch 14 across parts of the Florida Panhandle.

DISCUSSION...As the more vigorous portion of the broken band of
convection stretching from the South Carolina/Georgia coastal waters
westward across the Florida Panhandle continues to shift farther off
the Georgia coast, less-organized storms persist westward to the
Calhoun/Bay/Gulf county area of Florida.  Storms are ongoing near
and just to the cool side of convective outflow, where sufficient
CAPE and ample shear persist.  While short-term convective trends
have remained generally unchanged -- i.e. storms sub-severe,
increasing large-scale ascent is noted farther west into southeast
portions of Louisiana/Mississippi per WV and radar loops.  

At this time, it appears that a relative minimum in severe risk may
persist through the scheduled 22/00Z expiration of Tornado Watch 14.
However, an anticipated increase in risk later this evening may
require additional WW issuance near or to the northwest of the
current watch.

..Goss.. 01/21/2017

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

ATTN...WFO...TAE...MOB...

LAT...LON   30668350 29818438 29528517 30138598 30148666 30498651
            30688574 30468417 30668350

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 21, 3:00 AM CSTMesoscale DiscussionSPCEscambia, Okaloosa, Santa Rosa, Walton90 min
Jan 21, 3:56 AM CSTTornado WatchSPCEscambia, Holmes, Okaloosa, Santa Rosa, Walton8 hr
Jan 21, 7:41 AM CSTMesoscale DiscussionSPCEscambia, Holmes, Jackson, Okaloosa, Santa Rosa, Walton and 1 more94 min
Jan 21, 8:04 AM CSTTornado WatchSPCBay, Calhoun, Gadsden, Gulf, Jackson, Liberty and 1 more6 hr
Jan 21, 9:19 AM CSTMesoscale DiscussionSPCBay, Calhoun, Gadsden, Holmes, Jackson, Liberty and 3 more86 min
Jan 21, 12:06 PM CSTMesoscale DiscussionSPCBay, Calhoun, Gadsden, Gulf, Hamilton, Jackson and 6 more114 min
Jan 21, 1:12 PM CSTTornado WatchSPCBay, Calhoun, Franklin, Gadsden, Gulf, Jefferson and 3 more5 hr
Jan 21, 3:03 PM CSTMesoscale DiscussionSPCBaker, Columbia, Franklin, Gilchrist, Gulf, Hamilton and 9 more57 min

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.