SPC 2000Z Day 1 Outlook

Day 1 Outlook Image

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0138 PM CST Wed Nov 11 2020

Valid 112000Z - 121200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER WESTERN
PORTIONS OF THE FLORIDA PENINSULA...

...SUMMARY...
A few tornadoes are possible across parts of Florida mainly
northeast through southeast of the center of Hurricane Eta.

...20Z Update...

...FL...
As discussed in recently issued MCD 1971, convection within one of
the outer bands of Hurricane Eta has undergone some strengthening,
primarily from the western FL Keys northeastward into the
southwestern portion of the FL Peninsula. Lightning data confirms
this strengthening, with the cells about 20-30 miles north-northwest
of MTH show appreciable lightning density. Temperatures have warmed
into the low/mid 80s and mesoanalysis indicates about 1000-1500 J/kg
of MLCAPE. However, contrasting these thermodynamic improvements are
the weakening kinematic fields. The 18Z sounding from MFL indicates
0-1 km storm-relative helicity around 170 m2/s2, down from 220+
m2/s2 on the 12Z sounding. Even so, this parameter space remains
adequate for a few stronger storms capable of producing locally
strong wind gusts and perhaps a brief tornado or two. The 2% tornado
risk was expanded eastward to account for this band of storms. A 5%
wind area was also added to portions of central/south FL.

...NC/VA...
No changes needed to this portion of the outlook. Damaging wind
gusts still appear possible within any of the stronger cells.

..Mosier.. 11/11/2020

.PREV DISCUSSION... /ISSUED 1022 AM CST Wed Nov 11 2020/

...FL...
Hurricane Eta is moving slowly northward across the eastern Gulf of
Mexico, with outer bands affecting the western coast of the FL
Peninsula.  A few of the convective elements in these bands have
shown indications of weak low-level rotation.  Local VAD profiles
and forecast soundings show ample low-level shear for a risk of a
few spin-ups this afternoon.  However, CAM solutions suggest that
coverage of more discrete cells will be sparse.  Nevertheless, will
maintain the ongoing forecast with no changes.

...NC/VA...
Water vapor imagery shows a subtle shortwave trough over middle
TN/northern AL moving across the southern Appalachians.  This
feature will begin to affect parts of VA/NC later this afternoon
with slightly strengthening low/mid level winds and vertical shear. 
Scattered thunderstorms are expected to affect this region through
the day, with the increasing shear likely resulting in a few weakly
rotating storms.  Forecast hodographs are not particularly favorable
for tornadoes, but one or two of the storms could become
sufficiently organized to produce locally gusty/damaging winds.

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