Mesoscale Discussion 89

Issued

Feb 15, 2021, 11:24 AM CST (17:24 UTC)

Expired

Feb 15, 2021, 12:30 PM CST

In force

66 min

Issued by

the Storm Prediction Center

Concerning

Severe potential...tornado watch likely

Chance of a watch

95%

The Eglin Afb radar (KEVX), 21 km from the middle of the area, began a volume at 17:26 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.

• Tornado Watch 7Feb 15, 11:55 AM CST
• Tornado Watch 8Feb 15, 2:00 PM CST

597 
ACUS11 KWNS 151724
SWOMCD
SPC MCD 151724 
GAZ000-FLZ000-ALZ000-151830-

Mesoscale Discussion 0089
NWS Storm Prediction Center Norman OK
1124 AM CST Mon Feb 15 2021

Areas affected...the Florida Panhandle...southeastern Alabama...and
southwestern Georgia

Concerning...Severe potential...Tornado Watch likely 

Valid 151724Z - 151830Z

Probability of Watch Issuance...95 percent

SUMMARY...Risk for severe storms -- including potential for damaging
winds and a few tornadoes -- will increase into this afternoon, as
warm/moist air moves gradually inland.  A tornado watch will be
needed, most likely between 1830Z and 19Z.

DISCUSSION...Latest surface analysis shows the warm front -- at the
leading edge of a fairly well-modified Gulf boundary layer -- still
offshore over the northeastern Gulf of Mexico, but shifting
slowly/steadily northward.  A small band of thunderstorms --
exhibiting well-defined updraft rotation -- are ongoing south of
Mobile Bay, in very close proximity to the surface low.

As the low deepens and shifts northeastward in response to the
mid-level trough that will continue to pivot quickly northeastward
across the central Gulf Coast region and Mid South today, expect
resulting low-level theta-e advection to yield continued/gradual
destabilization inland.  While it remains difficult to discern how
far northward true surface-based CAPE will develop due to the
persistent/cool boundary layer in place, at least near-surface-based
storms are expected to spread as far north as far southeastern
Alabama and into southwestern Georgia later this afternoon.  

Meanwhile, the background shear profiles remain quite favorable for
rotating storms, with low-level east-southeasterly flow near the
warm front veering/increasing rapidly with height to
south-southwesterly at 50 kt at 1km, per the latest KEVX WSR-88D
VWP.  This flow field is suggestive of low-level vortex generation
and at least some risk for a strong tornado, though near-surface
thermodynamics remain a question mark as to degree of tornado risk. 
Still, risk appears great enough -- especially with southward extent
toward the coast -- that a tornado watch will be required.

..Goss/Grams.. 02/15/2021

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

ATTN...WFO...JAX...FFC...TAE...BMX...MOB...

LAT...LON   29158775 29728777 30038808 30558753 31168648 31798521
            31908367 31498310 30238337 28948443 29158775

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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.