Day 1 Severe Weather Outlook

Valid 111200Z – 121200Z

…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE LOWER MS VALLEY INTO THE CENTRAL GULF COAST STATES…

…SUMMARY…
Strong to severe thunderstorms may impact parts of the Ozarks into
the Mid-South, lower Mississippi Valley, and central Gulf Coast
states today. Isolated damaging winds and large hail may occur,
along with a couple tornadoes.

…Ozarks into the Mid-South and Lower Mississippi Valley…
A small cluster of thunderstorms will likely be ongoing at the start
of the period later this morning across northwestern AR and adjacent
southern MO. This convection is expected to continue southeastward
across AR and into parts of the Mid-South through the early
afternoon in tandem with a 30-40 kt southwesterly low-level jet.
These storms will eventually encounter greater low-level moisture
across central/southern AR and northern MS as they cross a surface
warm front. The potential for strong/gusty winds to reach the
surface and produce isolated damage should also gradually increase
as diurnal heating occurs ahead of the storms.

The southwesterly low-level jet is forecast to gradually weaken
through the afternoon as stronger forcing for ascent associated with
a large-scale upper trough shifts eastward across the OH/TN Valleys
and away from the lower MS Valley. Still, strong northwesterly
mid-level flow (50 kt at 500 mb) will remain over this region,
which should support similar values of effective bulk shear. There
may be some chance for the bowing cluster to evolve into a broken
line of supercells by late morning/early afternoon before the
low-level jet weakens substantially. If this occurs, then isolated
large hail and perhaps a couple tornadoes would be possible, mainly
across parts of eastern AR into northern MS where somewhat greater
low-level moisture should be present. Otherwise, mainly an isolated
severe hail/wind threat may continue into parts of northern/central
AL through the early evening before instability wanes with eastward
extent.

…Central/East Texas…
A weak surface boundary is forecast to remain nearly stationary
across parts of central/east TX through much of the day. Although
large-scale ascent should remain nebulous/weak across this region,
there is a conditional threat that storms could form along this
boundary by late afternoon. If storm initiation can occur, then
isolated large hail and strong/gusty winds would be possible given
around 35-40 kt of effective bulk shear and 500-1500 J/kg of MLCAPE.
Most 00Z guidance suggests that storm coverage across this region
will be sparse at best, and a reduction in severe hail/wind
probabilities may be warranted if current model trends continue.

..Gleason.. 03/11/2020

$$

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