Severe Storm Outlook Narrative (AC)
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000
ACUS02 KWNS 171705
SWODY2
SPC AC 171704

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1204 PM CDT Sun Mar 17 2024

Valid 181200Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE FLORIDA PENINSULA...

...SUMMARY...
Strong thunderstorms may move inland off the Gulf of Mexico into
portions of the northern and central Florida peninsula early Monday.
Additional thunderstorms may develop during the afternoon along the
east-central and southeast Florida coast. Strong gusts and hail may
accompany this activity.

...FL Peninsula...

An upper trough over the Great Lakes and MS Valley will pivot
east/southeast across the eastern U.S. on Monday. Forecast guidance
depicts a shortwave perturbation in the base of the trough over the
northern Gulf of Mexico shifting east across northern/north-central
FL Monday morning. Deep-layer westerly flow will increase with
southward extent across the FL Panhandle through the afternoon, with
30-40 kt 850-700 mb flow common ahead of southward-sagging surface
boundary.

Showers and thunderstorms may be ongoing across parts of
north-central FL Monday morning. Gusty winds may accompany this
activity as it spreads east the first few hours of the forecast
period. A more conditional severe thunderstorm risk may develop
during the afternoon further south across parts of the
east-central/southeast coast.

The NAM appears to be an outlier with the strength of an EML,
maintaining capping through the period. The RAP/HRRR/GFS show weaker
capping around 700 mb with full erosion of the cap by afternoon.
Given favorable vertical shear (0-6 effective shear around 40 kt),
steep midlevel lapse rates (around 7-7.5 C/km) and MLCAPE around
1500-2000 J/kg, at least a conditional risk for a couple of severe
storms appears plausible. Large-scale ascent will remain weak over
the area, and veered low-level flow will limit low-level convergence
along the southward-developing surface front. If a well-defined sea
breeze develops along the southeast Peninsula, this could allow for
a few storms to develop during the afternoon/early evening, posing a
conditional risk for large hail and strong gusts. For this reason,
have expanded the Marginal risk (level 1 of 5) to encompass the
southeast Peninsula.

..Leitman.. 03/17/2024

$$


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