Mesoscale Discussion 2273
NWS Storm Prediction Center Norman OK
0440 AM CST Fri Dec 26 2025

Areas affected...Parts of central and southern Lower Michigan

Concerning...Freezing rain 

Valid 261040Z - 261645Z

SUMMARY...Freezing rain will increase in intensity and coverage
while spreading eastward across parts of central and southern Lower
Michigan during the 12-16Z time frame.

DISCUSSION...The latest mosaic radar data shows a swath of mixed
precipitation spreading eastward into Lower MI -- where surface
pressure is falling rapidly (-4 to -5 mb in the last two hours over
west-central Lower MI). This activity is focused ahead of an
eastward-advancing shortwave trough and within a broad zone of
low-level warm advection. As the trough continues eastward this
morning and gains some amplitude, deep-layer forcing for ascent will
strengthen while focusing over Lower MI. As a result, precipitation
will increase in both intensity and coverage as the low/mid-levels
saturate amid the strengthening ascent. Additionally, steepening
midlevel lapse rates should yield weak elevated buoyancy and a
potential convective enhancement to precipitation rates. 

As low-level warm advection strengthens, a substantial warm nose
centered around 850 mb will favor complete melting of descending
hydrometeors before re-freezing at the surface. The strong lift
(with potential convective enhancement) and aforementioned thermal
profile will contribute to freezing rain rates upwards of 0.05
inches per hour (locally higher under the more robust convectively
enhanced cores). The onset of the heavier rates is expected between
12-16Z, but should persist beyond that period while spreading
eastward across southeastern Lower MI.

..Weinman.. 12/26/2025

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...DTX...APX...GRR...

LAT...LON   42448488 42888549 43378619 43738637 43958622 44168555
            44138477 43868383 43478256 43038230 42188279 41918342
            42018398 42448488 

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0211 AM CST Fri Dec 26 2025

Valid 281200Z - 291200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN MO/AR TO
TN/KY/OH...

...SUMMARY...
Isolated severe thunderstorms are possible on Sunday into Sunday
night from Arkansas and Missouri into parts of the Ohio and
Tennessee Valleys.

...MO/AR to TN/KY/OH...
Phasing of multiple shortwave impulses will support amplification of
an upper trough, as it progresses from the High Plains to the
North-Central States. This will induce deepening of a surface
cyclone from near the Ozarks to the eastern Great Lakes. Attendant
cold front will accelerate on Sunday night as it quickly moves east
across the OH Valley and south into the Northwest Gulf.

Isolated to scattered elevated convection within the strengthening
low-level warm conveyor should persist, yielding a northern limiter
to potential severe thunderstorms later in the day through Sunday
night. Outside of the likely too cool/stable 00Z NAM, bulk of
preferred guidance suggest weak surface-based destabilization may
occur as a broad plume of upper 50s to low 60s surface dewpoints
becomes established ahead of the front and deepening cyclone. Richer
boundary-layer moisture with at least mid 60s surface dewpoints
should largely hold over the Lower MS Valley and Deep South. 

Late afternoon surface-based storms may develop over the Mid-MS
Valley/Ozarks vicinity. Amid broadening large-scale ascent, upscale
growth into a thin but long QLCS seems plausible along the front
given the orientation of the deep-layer winds. Despite only minimal
to meager surface-based instability on Sunday night, intensifying
wind fields throughout the troposphere could support a convective
line with/without lightning. This may yield a threat of sporadic
strong to severe gusts producing at least isolated damaging winds.

..Grams.. 12/26/2025

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0253 AM CST Fri Dec 26 2025

Valid 291200Z - 031200Z

...DISCUSSION...
D4/Monday will feature conditionally favorable strong low to
mid-level flow along/ahead of a cold front moving east across the
Southeast. The intense eastern Great Lakes/southeast ON cyclone
should occlude as a secondary cyclone forms along coastal ME into
the Canadian Maritimes. Guidance is fairly consistent for this time
frame with indications of minimal instability along the trailing
portion of the cold front, as well as diminishing large-scale
ascent/convective signal through the day. Severe thunderstorm wind
probabilities appear at or below 5 percent. 

The continental airmass spreading across the Gulf in the wake of the
frontal passage should yield minimal severe potential mid-week.
Towards late week, return flow will support airmass modification
along the western Gulf Coast. The EC-AIFS hints at a low-amplitude
shortwave impulse in the D8/Friday time frame, which could support a
return to non-negligible severe potential.