Next 15-days Temperature Anomaly | Ensemble Mean

The coldest air in the 15-day mean is centered over Iowa and Chicago — likely due to the snow cover/depth remaining for the next 1-2 weeks without a sustained warmup in the cards. Also, depending upon the track of a potential Nor’easter in the middle of next week, we may have long-lasting snow depth into December across New England.

We really went from those quite warm days of autumn to full-tilt winter in like 2-weeks.

Snow Depth Forecast in 10-days | into December 9, 2025

Lower 48 precipitation type + MSLP for the next 6-days | ECMWF 18z

Headlines Saturday Morning

1. Powerful Midwest —> Great Lakes storm system moves quickly into Quebec dragging another strong Arctic cold front across the eastern U.S.

2. Nor’easter watch! The ECMWF flagship model keeps flipping between a major 12-18” jackpot over New England to a more management 3-6” event with the difference due to phasing of surface low with the upper-level trough. Tricky forecast! Note the heavier rain along the Gulf coast into the Southeast.

3. Next 2-weeks remain stuck with well below normal temperatures across the Eastern U.S. as the mega-load of “Polar Vortex” cold pool wobbles around Hudson/James Bay waiting for any shortwave out of the Pacific to capture a lobe.

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Temperature Analysis | 9:45 AM ET

Subzero air in Montana with teens and lower 20s into Minneapolis. Near freezing in Chicago and Detroit

Temperature Anomaly | 9:45 AM ET

Lower 48 Temperature Anomaly was -4.0°F below normal

Midwest —> Great Lakes Snow Storm Radar through 10:20 AM ET

HRRR 12z | Simulated Radar Next 48-hours into Monday Morning

The front fizzles out as it reaches the Southeast with only some lighter showers. The main energy with the surface low quickly tracks into Ontario/Quebec and takes the QPF with it —> but we’ll see quite a blanket of snowfall in excess of a foot for huge area.

Total Snowfall From HRRR Next 18-hours | 12z —> Sunday 1 AM ET

Like taking a paint brush and coloring the canvas with beautiful hues of blue and pink, my favorite maps (aside from precipitable water)

Lower 48 | Frontal Boundaries and storm systems today

NWS Precipitation Next 72-hours

Heavy rain: 1” to 2”+ from the next storm system / potential Nor’easter into early next week across the Deep South and Gulf Coast into the Southeast.

NWS Snowfall Next 72-hours

Chicago, Milwaukee, Des Moines > 12” … we’ll see how much southern Michigan sees — but at least a foot in Kalamazoo, and over 6” in Detroit. Plenty of shoveling and plowing for huge population — roughly 28.7 million from the NWS NDFD through 72-hours for 6-inches+

RRFS-A through 84-hours (Tuesday 2 PM ET) | Snowfall totals

This map is beautiful … RRFS-A is a 3-km resolution model and my color table is dazzling.

Blend of Models | 7 Days Precipitation Total (includes liquid from snow)

Total Snowfall Next 7-Days

The Blend of Models (ensemble mean) showing snowfall for Northeast and New England that’s generally in the 2” range for NYC and Boston, maybe a little more. Fine line between huge snow storm from the Nor’easter, or a whiff.

Saturday High Temperatures

Sunday Low Temperatures

176 million below freezing (Lower 48 average low is 25.2°F)

Sunday High Temperatures

Monday Low Temperatures

171 million below freezing (Lower 48 average low is 23.0°F)

Monday High Temperatures

New AI-GFS | 500 mb Temperatures | Polar Vortex Watch Next 10-days

Amazing cold locked up over Hudson / James Bay with -50°C coldest air at 500 mb perilously close to the Lower 48 borders — waiting for passing shortwaves coming out of the Gulf of Alaska to pull down or snatch lobes.

ECMWF EPS 00z | 15-day Ensemble Mean Temperature Anomaly

Alaska goes into the deep freeze — but also the Great Lakes, too

Atmospheric Moisture | Precipitable Water Next 6-days

My favorite parameter! The white coloring is the coldest/dries of the tropospheric “Polar Vortex” and you can trace the origin of the air from Greenland and the Arctic Ocean over next 6-days.

ECMWF AIFS 06z | Height Anomaly (500 hPa) Next 10-days

Integrated Vapor Transport Next 10-days

Parameter used for monitoring “atmospheric rivers”

European Weather Next 6-days

Note the preponderance of “green” for precipitation type of rain … warmer pattern

ECMWF 00z and 06z | Snowfall | Next 6-days

New England — Nor’easter watch!

ECMWF EPS 00z | Ensemble Median Snowfall Next 10-days

Median from ensembles at 00z was 5” in Boston — right on the edge

ECMWF EPS 00z | Ensemble Snowfall Probability > 1” | Next 10-days

Need to look at the snowfall margin again in the Southeast — thankfully 0% chance in Atlanta for next 10-days, but this is an impressive cold pattern + snow for early December.

ECMWF EPS 00z | Ensemble Snowfall Probability > 6” | Next 10-days

Temperature Anomaly | Next 15-days | ECMWF EPS 00z

5-Day Chunk #1 | Temperature Anomaly | Nov 29 - Dec 3

5-Day Chunk #2 | Temperature Anomaly | Dec 4 - Dec 8

5-Day Chunk #3 | Temperature Anomaly | Dec 9 - Dec 13

Snowfall Analysis | October 2025 - today

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