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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.


Tuesday, May 14, 2024

SPC May 14, 2024 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1248 AM CDT Tue May 14 2024

Valid 141200Z - 151200Z


Severe thunderstorms will be possible today over parts of central
and northern Florida into extreme southern Georgia, with damaging
gusts and a tornado or two the main threats. Isolated severe storms
will also be possible across portions of the Ohio and Tennessee
Valleys into the Carolina Piedmont, as well as the central
Rockies/High Plains and parts of western Texas.

A mid-level trough will slowly progress across the Southeast as a
second, low amplitude trough traverses the central Rockies today.
Multiple embedded impulses should pivot around the Southeast
mid-level trough and eject into the Atlantic, providing multiple
rounds of deep-layer ascent to support a few rounds of thunderstorms
over northern into central FL. Accompanying the southeast mid-level
trough is a weak surface low over the OH/TN Valleys, which will aid
in the northward transport of low-level moisture and associated
buoyancy. Given modest vertical wind shear in place, adequate
buoyancy will support the organization of at least isolated strong
to severe thunderstorms over the OH/TN Valleys, with a more
concentrated severe risk possible in northern FL along a residual
baroclinic boundary. Elsewhere across the central Rockies/High
Plains, enough deep-layer ascent will support scattered
thunderstorms atop a well-mixed, heated boundary layer to support an
isolated severe threat.

...Central and northern FL into extreme southern GA...
A baroclinic boundary will become reinforced somewhere over northern
FL with the passage of an MCS at the start of the period. Along this
boundary, the MCS should intensify as a 500 mb jet streak
overspreads the moist, destabilizing boundary layer. 7+ C/km
mid-level lapse rates overspreading 70+ F surface dewpoints will
boost MLCAPE to the 2000-3000 J/kg range. Modest low-level hodograph
curvature and some elongation suggests that embedded bowing
structures and mesovortices could develop, accompanied by a damaging
gust and tornado risk. After the first round of storms diminish by
the afternoon, a second round of strong to potentially severe
thunderstorms could develop over northern FL as a second mid-level
impulse embedded in the upper trough overspreads the region. Severe
coverage with this second round of storms will be more conditional
on how much airmass recovery can occur between both rounds of

...OH and TN Valleys into the Carolina Piedmont...
Deep-layer moisture will advect northward ahead of the meandering
surface low, beneath a nearly uncapped troposphere. As such, diurnal
heating needs only to boost surface temperatures into the lower 70s
F to initiate convection. These temperatures, along with low to mid
60s F dewpoints, will support around 1000 J/kg SBCAPE by afternoon.
Flow aloft is not expected to be overly strong, with slightly curved
and short hodographs likely resulting in mainly pulse cellular and
multicellular storms. Damaging gusts and hail will be the main
threats, though a brief tornado or two cannot be ruled out.

...Central Rockies into the Central High Plains...
The approach of a low-amplitude mid-level trough, and diurnal
heating of an uncapped boundary layer, will support scattered to
numerous thunderstorms during the afternoon and evening hours. A
deep and dry boundary layer should become established by afternoon
peak heating, resulting in high-based pulse- and multicell storms
capable of producing isolated severe gusts (given 7-9 C/km low and
mid-level lapse rates). A couple instances of severe hail may also
accompany storms over the central High Plains, where low-level
moisture is slightly more favorable.

...Portions of western Texas...
A narrow corridor of thunderstorm potential exists ahead of a
diffuse dryline over western TX by afternoon peak heating, where the
dryline circulation may be strong enough to assist in the initiation
of isolated thunderstorms amid minimal CINH. Low-level moisture will
be meager, with mid 80s F surface temperatures and low 50s F
dewpoints contributing to over 30 F spreads, so any storms that
develop will be high based. Somewhat elongated hodographs suggest
that supercells would be the dominant mode of convection,
accompanied by an isolated severe wind/hail risk.

..Squitieri.. 05/14/2024

SUNRISE AND SUNSET TIMES IN UTC (if you're not logged in to Google)
CHICAGO UTC-6 during CST (Central Standard Time, e.g., winter)
CHICAGO UTC-5 during CDT (Daylight Savings Time, e.g., summer)