SPC May 2, 2017 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0242 PM CDT Tue May 02 2017

Valid 022000Z - 031200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS...

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN AND CENTRAL PLAINS...

...SUMMARY...
A cluster of severe storms may develop this evening into the early
overnight over the Texas Panhandle and northern Oklahoma with hail
as the primary hazard.

...DISCUSSION...
The only change to the outlook is to move the thunder line across
the Florida peninsula, southward to near a cold front positioned
just south of the Tampa and Orlando vicinities.

..Broyles.. 05/02/2017

.PREV DISCUSSION... /ISSUED 1131 AM CDT Tue May 02 2017/

...TX/OK Panhandles and Northern OK...
As s shortwave trough over the eastern Great Basin amplifies towards
the southern High Plains, a west/east-oriented frontal zone will
sharpen. Moisture characterized by middle 50s surface dew points
should become established along the boundary, well-separated from
returning western Gulf moisture. Storms will likely develop on the
cool side of the front this evening and increase in coverage along
it into the overnight. Very steep mid-level lapse rates and
strengthening mid/upper-level wind profiles should foster updraft
rotation and a primary severe risk of hail, with a secondary risk
for wind. Probable cluster mode and relatively modest buoyancy
should preclude more substantial hail size/coverage, but overall
threat appears sufficient for a slight risk.

...Upper TX coast...
Rich, gulf boundary-layer moisture should return by late in the
period beneath a mid-level cap. As MLCIN weakens, a conditional risk
for a tornado would exist. However, the paucity of convective
development in morning guidance and likelihood for a more robust cap
than typically indicated in forecast soundings suggest this risk is
too low to warrant a continued severe risk delineation.

...Central/South FL...
Convection is ongoing along a cold front and additional development
is expected this afternoon along sea-breeze circulations. 12Z
observed soundings sampled weak tropospheric flow and 500-300 mb
lapse rates. This suggests storms should be of pulse type with
modest updraft speed. Given the presence of the front and the
likelihood for numerous storms, locally strong wind gusts and small
hail appear possible. Organized severe storms are not expected.

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