Mesoscale Discussion 2286
NWS Storm Prediction Center Norman OK
0332 AM CST Mon Dec 29 2025

Areas affected...Parts of Upper Michigan and far northern Lower
Michigan

Concerning...Heavy snow 

Valid 290932Z - 291530Z

SUMMARY...Banded heavy snow with rates of 1-2 inches per hour and
periods of blizzard conditions are expected through the morning
hours.

DISCUSSION...To the west/northwest of a very deep low pressure
system (983 mb surface low over Lake Huron), substantial deep-layer
lift is overspreading a cold, deeply saturated profile over Upper MI
and vicinity. The combination of this lift through a deep/saturated
DGZ and isothermal layer below will promote efficient crystal growth
and aggregation. As as result, widespread and prolonged heavy
snowfall rates of 1-1.5 inches per hour are expected, with even
higher rates to around 2 inches per hour over the higher terrain and
beneath the core of more organized banding. In addition to these
substantial and prolonged rates, a very tight pressure gradient
peripheral to the deep surface low and strong low-level jet
(50-60-kt flow in the lowest 1 km AGL per MQT VWP) will promote
40-50 mph gusts and intermittent blizzard conditions in conjunction
with the heavy snowfall rates.

..Weinman.. 12/29/2025

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

ATTN...WFO...APX...MQT...

LAT...LON   45458526 45558610 45788701 46168815 46508849 46718842
            46828799 46578760 46408716 46428653 46618622 46738507
            46538424 46158371 45818366 45538398 45398451 45458526 

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0645 AM CST Mon Dec 29 2025

Valid 291300Z - 301200Z

...NO THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms will not occur across the contiguous United
States through tonight.

...Synopsis...
Water-vapor imagery this morning shows a trough over the Great Lakes
and much of the eastern U.S. whereas a split-flow pattern prevails
over the West.  A cold front will continue south through much of the
Gulf of America and move east of the Eastern Seaboard during the
period.  High pressure centered over the south-central states will
lead to cool/stable conditions over much of the Lower 48.

..Smith/Weinman.. 12/29/2025

Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0311 AM CST Mon Dec 29 2025

Valid 011200Z - 061200Z

...DISCUSSION...
Guidance consensus indicates a lower-amplitude shortwave trough will
approach the southern CA coast at 12Z Thursday. This feature appears
increasingly likely to progress east across the southern states
through late week, initially inducing cyclogenesis over the southern
High Plains. This will aid in strengthening low-level moisture
return over the western Gulf, after a pervasive continental air mass
intrusion today.

Increasing convective potential is anticipated around late D5/Friday
to D6/Saturday across the Gulf Coast States from LA to north FL, and
into parts of the Deep South. Run-to-run-predictability and spread
across guidance remains less-than-ideal for timing/location of
amplification/dampening details for this shortwave trough. Bulk of
signals are still for a modest surface cyclone and seemingly
lower-end severe risk. But there's enough minority signal to warrant
concern for a potential 15 percent area in later outlook cycles.

Day 2 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0159 AM CST Mon Dec 29 2025

Valid 301200Z - 311200Z

...Synopsis...
A broad northwesterly mid-level flow regime will prevail across the
eastern half of the CONUS tomorrow (Tuesday), with multiple embedded
impulses poised to traverse this flow and encourage the continued
southward shunting of surface high pressure. Offshore flow within a
post-cold-frontal regime will encourage 10-15 mph sustained
northwesterly surface winds amid 25-35 percent RH along portions of
the Carolinas, southward to the Florida Peninsula, where Elevated
highlights have been introduced. Meanwhile, southwesterly surface
flow pivoting around a surface high will support 15 mph sustained
winds coinciding with 15-25 percent RH atop dry fuels over parts of
the southern Plains, warranting Elevated highlights.

..Squitieri.. 12/29/2025

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