Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
SPC AC 071300
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0700 AM CST Tue Feb 07 2017
Valid 071300Z - 081200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF LA/MS/AL TO FL PANHANDLE...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE GULF
COAST STATES/LOWER MS RIVER VALLEY AND TN VALLEY...
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
GULF COAST TO THE OHIO VALLEY AND MIDWEST...
Severe thunderstorms are expected today especially across the lower
Mississippi Valley and central Gulf Coast states, but some strong to
severe thunderstorms may occur as far north as the Tennessee Valley
and Ohio Valley.
...Portions of LA/MS/AL to FL Panhandle...
A southern-stream shortwave trough (and related mid/high-level speed
max) will continue to amplify and spread generally
east-southeastward today toward the central Gulf Coast States.
Strengthening low/mid-level southwesterly winds will support the
continued northeastward transport of low/middle 60s F surface
dewpoints across additional portions of MS/AL.
Showers/thunderstorms are already increasing within the modestly
moist early-day warm sector across southern/eastern LA into MS. Many
of these storms should become increasingly surface based into late
morning/early afternoon as additional moistening and destabilization
occurs. 12Z observed soundings from Shreveport (SHV) and Lake
Charles (LCH) sample severe-favorable thermodynamic profiles with
very steep mid-level lapse near or excess of 8.0 C/km, aside from
35-45 kt of effective shear.
Steadily increasing deep-tropospheric winds and lengthening
hodographs, in conjunction with cool mid-level temperatures (roughly
-14C to -17C at 500 mb) and steepening lapse rates, appears likely
to support supercells capable of large hail, along with some
tornado/damaging wind risk, especially from mid/late morning into
the afternoon. Storms may merge over time and grow upscale with at
least a modestly increased damaging wind risk into AL and the FL
Panhandle this afternoon, although the eastward progression of the
presumed convective line may eventually outrun the greater low-level
For additional details on the expected early-day evolution of
storms, please reference Mesoscale Discussion 144.
...Tennessee Valley/Ohio Valley/Midwest...
Ahead of a cold front, moist advection will continue to occur in
concert with 50+ knot low-level southwesterly winds. Mostly linear
bands of strong to locally severe convection are ongoing early this
morning from east-central AR into western TN. These storms should
develop eastward across additional portions of TN and northern
portions of MS/AL. While these storms are likely to develop east of
the primary moist/instability axis, a modestly increasing potential
for damaging winds, some hail and brief tornado risk can be expected
during the day eastward into at least middle TN and northern
portions of MS/AL.
Farther north into the Ohio Valley and Midwest, current thinking is
that extensive ongoing precipitation south of the Ohio River and
related cloud cover will tend to hinder appreciable destabilization.
While weak buoyancy/strong vertical shear could support some
stronger/potentially severe low-topped storms, the overall severe
risk should remain limited.
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z