Mesoscale Discussion 620

Issued

May 1, 2017, 7:15 AM CDT (12:15 UTC)

Expired

May 1, 2017, 9:15 AM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Chance of a watch

20%

The Ft Rucker radar (KEOX), 50 km from the middle of the area, began a volume at 12:19 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

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822 
ACUS11 KWNS 011216
SWOMCD
SPC MCD 011215 
GAZ000-FLZ000-ALZ000-011415-

Mesoscale Discussion 0620
NWS Storm Prediction Center Norman OK
0715 AM CDT Mon May 01 2017

Areas affected...Southeast AL...southwest into central GA...and the
FL Panhandle

Concerning...Severe potential...Watch unlikely 

Valid 011215Z - 011415Z

Probability of Watch Issuance...20 percent

SUMMARY...An isolated strong/severe storm risk should persist
through this morning across southeast AL into portions of
west-central and southwest GA, and the FL Panhandle this morning.

DISCUSSION...Boundary layer destabilization (surface temperatures
rises of 3-6 F and dew point rises around 2 F) has been underway for
the last few hours across southeast AL into west-central and
southwest GA to parts of the FL panhandle in advance of a cold front
approaching this region.  11-12Z surface analysis showed the cold
front extended southward from the middle OH Valley through middle
TN, far northwest GA, southeast AL, and the western FL Panhandle. 
Analysis of area VADs per WSR-88Ds indicated deep-layer and
low-level shear are more than sufficient for organized storms this
morning, given sustained southerly 1-km agl winds of 45-50 kt, with
0-1 km shear of 30-35 kt and 0-1 km srh of 200-300 m2/s2.  Weak
instability across this region per objective analyses within this
strongly sheared environment has already supported episodic low and
mid-level rotational couplets with the ongoing storms along the
front in south-central to part of southeast AL.

Extensive cloudiness downstream of the cold front should limit
surface heating, though even marginal instability should prove
sufficient for additional organized storms as the cold front
advances east into the discussion area through mid-late morning. 
Given the favorable aforementioned shear with the low-level jet
sustaining speeds of 45-50 kt this morning, storm rotations will
remain possible with a low-end risk for a tornado and/or strong wind
gust.

..Peters/Guyer.. 05/01/2017

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

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

LAT...LON   30598644 31368599 31958560 32388522 32838479 32948439
            32868389 32358370 31598371 30988383 30658399 30448433
            30278507 30368550 30438606 30598644

Mesoscale Discussions in Georgia, 2017Mesoscale Discussions in Alabama, 2017Mesoscale Discussions in Florida, 2017Every mesoscale discussion in 2017

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.