SPC Jun 9, 2025 1630 UTC Day 1 Convective Outlook

SPC 1630Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1127 AM CDT Mon Jun 09 2025

Valid 091630Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
OVER PORTIONS OF THE GULF COAST STATES INTO SOUTHEAST...OVER
PORTIONS OF THE TN/OH VALLEYS AND SOUTHERN LOWER MI...AND OVER THE
SOUTHERN HIGH PLAINS...

...SUMMARY...
Scattered strong to severe thunderstorm development appears probable
today across parts of the Tennessee and Ohio Valleys, over Lower MI,
from lower Mississippi Valley into Southeast, and over the southern
High Plains.

...Southeast TX into the Southeast...
Morning observations and satellite/radar imagery reveals a complex
pattern across TX and Southeast as a result of extensive overnight
convection. Satellite imagery shows the vorticity maximum from the
overnight storms in TX is over the AR/LA vicinity, with the
associated outflow extending from southeast TX through south TX.
Overnight storms also developed over central MS and southern AL,
with the resulting MCV now in the central MS/AL border vicinity. All
of these features will likely provide the impetus for thunderstorm
development today, but the unfocused nature of the overall pattern
leads to larger-than-usual uncertain for Day 1. 

Current expectation is for redevelopment over MS behind the MCV over
southern LA/MS/AL as the MCV over AR/LA moves into the region later
this afternoon. Given the combination of buoyancy and shear, this
area appears to have the greater chance for severe than areas
farther west across TX, where capping could limit coverage, or
downstream across the GA/Carolinas where destabilization will likely
be more limited. Damaging gusts are the primary risk across the
entire region via both water-loaded downbursts and bowing line
segments. Some isolated hail and a brief tornado or two are also
possible.

...TN/OH Valleys...
Recent surface analysis places a surface low over the AR/TN/MO
border intersection, with a weak cold front extending northeastward
from this low to another low over western Lake Ontario. Moderate
low-level moisture (i.e. dewpoints around 62-64 deg F) exists ahead
of this front. General expectation is for thunderstorm development
along and ahead of this front as it moves eastward and downstream
airmass diurnally destabilizes. Two areas within this broader zone
that appear to have a relatively greater severe potential are across
middle TN, where the ongoing storms could become loosely organized
into a forward-propagating line, and across eastern OH/western PA,
where stronger shear and greater forcing for ascent could result in
bowing line segments.

...Lower MI...
Strong heating is anticipated across Lower MI today, resulting in a
deeply mixed boundary layer. Shortwave trough rotating through the
base of the larger upper low centered over WI is expected to move
into the region this afternoon, interacting with this deeply mixed
and destabilized boundary layer to support thunderstorm development.
Some stronger low/mid-level flow will accompany this shortwave as
well, and the overall setup appears favorable for line segments
capable of damaging gusts. Severe coverage is expected to be high
enough to merit upgrading to 15% wind probabilities across southern
Lower MI.

...Southern High Plains...
Low-level moisture will continue to advect northwestward into west
TX and eastern NM today, with mid to upper 60s dewpoints across west
TX and low to mid 60s dewpoints in eastern NM by this evening. This
moisture advection and resulting buoyancy will provide a favorable
environment for storms to persist as the move off the higher terrain
this evening. Upscale growth into a southeastward-progressing
convective line appears probable, with this line moving across
east-central/southeast NM and into west TX. Strong to severe gusts
are possible within this line.

Additionally, a few storms are possible along and north of the
modified outflow boundary this evening. Steep lapse rates, ample
low-level moisture, and a unidirectional mid to upper-level westerly
wind profile with increasing speed with height will support the
potential for large to very large hail with these storms.

..Mosier/Thornton.. 06/09/2025

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