National Weather Service Issues Wide-Ranging Winter Alerts as Arctic Air Surges
A fresh blast of Arctic air is driving a busy day of warnings, watches, and advisories from the National Weather Service, with hazardous conditions unfolding from the Great Lakes to the Northern Rockies and pockets of severe-weather risk along the Gulf Coast. The agency cautions that impacts will vary widely by region: blizzard-like snow bands in the snowbelts, dangerous wind chills in parts of the Midwest, and travel-disrupting mountain snow in the Intermountain West.
National Weather Service highlights for December 4
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Great Lakes snow machine: Persistent northwest flow is fueling lake-effect snow across Michigan’s Upper Peninsula and into parts of northern Lower Michigan and western New York. Localized squalls can drop visibility to near zero and create rapid ice on untreated roads.
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Subzero wind chills in the Midwest: Behind the front, temperatures and dew points are plunging. The National Weather Service is flagging single-digit temperatures and subzero wind chills at times for portions of Indiana and neighboring states, especially overnight and early Friday.
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Heavy mountain snow in the West: Successive waves are targeting Wyoming’s Teton, Gros Ventre, Salt River and Wyoming Ranges, and adjacent high terrain. Totals of 1–2 feet are possible in favored elevations by the weekend, with gusty winds worsening visibility on passes.
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Gulf Coast thunderstorms: Along the northern Gulf, a surface low and warm frontal boundary are supporting clusters of thunderstorms from southeast Texas through coastal Louisiana into the Florida Panhandle. A few storms could pulse strong where instability overlaps the boundary.
Who is under the most significant alerts?
The National Weather Service has issued or maintained a mix of products today, including:
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Winter Storm Warnings and Advisories: Northern Rockies and high terrain of Wyoming and adjacent Montana; lake-effect corridors downwind of Lakes Superior and Ontario.
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Wind Chill Advisories/Precautions: Interior portions of the Midwest where brisk northwest winds accompany the coldest air of the season so far.
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Short-Fused Snow Squall Warnings (possible): In active snowbelt bands where whiteout conditions develop quickly.
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Flooding/Coastal Hazards (localized): Along parts of the Gulf Coast where heavier downpours and strong onshore flow coincide with higher tides.
Always check your specific zone forecast and alert map; county lines can split markedly different outcomes over short distances.
Timing and impacts to expect
| Region | Main Hazard | Peak Window (Local) | Travel Risk |
|---|---|---|---|
| Upper Great Lakes (U.P. of MI, N. Lower MI) | Lake-effect snow, squalls | Through tonight into Friday morning | High in bands: whiteouts, slick roads |
| W. NY & Tug Hill | Snow bands, brief squalls | This afternoon–late tonight | High along I-81 and secondary roads |
| WY/MT High Terrain | Heavy mountain snow, blowing snow | This afternoon–Saturday | Difficult passes; intermittent closures |
| IN/Lower Midwest | Bitter wind chills, refreeze | Tonight–Friday dawn | Black ice on bridges/overpasses |
| TX–FL Panhandle (coastal) | Thunderstorms, heavy rain | Today–tonight | Ponding; brief gusty winds |
Schedules subject to change with new observations and model trends.
Why this setup is potent
The pattern features a deep trough over the central U.S. with strong northwest flow aloft. Cold air pouring over the comparatively warm Great Lakes maximizes instability and moisture flux, a textbook recipe for narrow but intense snow bands. Farther west, embedded shortwaves wring out Pacific moisture over high terrain, enhancing snowfall rates. Along the Gulf Coast, the juxtaposition of a surface low, a lifting warm front, and a ribbon of upper-level divergence provides enough lift for repeated thunderstorm clusters.
Safety guidance from National Weather Service best practices
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If you must drive in snow belts: Slow down immediately when entering a squall; visibility can collapse from miles to near zero in seconds. Avoid sudden braking, increase following distance, and use low beams.
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Prepare for wind chills: Dress in layers, cover exposed skin, and limit time outdoors. Keep a winter kit in the car (blanket, charger, scraper, snacks).
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Mountain travel: Check pass status and chain requirements before departure; carry traction devices and be prepared for rapid closures.
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Gulf Coast storms: Never drive through flooded roadways. If thunder roars, go indoors—lightning can strike miles from the core of a storm.
What to watch next
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Band placement shifts: Subtle wind direction changes can relocate lake-effect bands by county; communities outside today’s heaviest snow could be targeted tonight.
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Secondary shot of cold: A reinforcing front late Friday into Saturday may extend wind chill issues deeper into the Ohio Valley.
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Weekend mountain totals: Orographic enhancement could push some high-elevation storm totals past 2 feet, with blowing snow lingering even after rates ease.
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Coastal lows: Any surface wave tracking along the Gulf boundary tonight could focus heavier rain and a brief strong-storm corridor before moving east.
The National Weather Service continues to update warnings, advisories, and hour-by-hour forecasts as new data arrive. Conditions can deteriorate quickly in the highlighted zones today; plan conservatively and check your local forecast office before heading out.
