{ "number": 471, "headline": "December 25, 2024 Wednesday Winter Weather", "standfirst": "Will Nor'easter next week have enough cold air?", "desk": "winter", "dateline": { "place": "Weather Trader", "state": null, "lat": null, "lon": null, "site_key": null, "site_name": null, "site_url": null, "accent": null }, "edition": "2024-12-26", "published": "2024-12-26T00:10:45.365000Z", "updated": null, "access": "free", "body_html": "
\"\"

Special Holiday Offer to Subscribe or Upgrade to Annual plan for 20% off. Your support is important for research, development, and growth of this platform into 2025.

Get 20% off forever

Good evening and Merry Christmas!

Today\u2019s weather was mostly quiet except for the Pacific Northwest. A warmer and wetter pattern takes over for the next 4-5 days before a subtle pattern shift allows colder Canadian continental air to flood into the Eastern U.S.

By next Wednesday, a potential Nor\u2019easter could develop but looks like mostly rain with temperatures too warm for significant snow. However, the low tracks into Canada and stalls out \u2014 its circulation allows NW winds to drag Arctic air all the way into the Southeast by the following weekend. This is a Day 7-10 time period event, so way down the road.

In the meantime, we\u2019ll deal with a lot of rain across the Mississippi River Valley, and several atmospheric rivers bombarding the West Coast \u2014 from Central California coast northward into OR/WA.

ECMWF 12z precipitation type and MSLP next 10-days

\"\"

Severe Weather and Heavy Rain on Thursday

\"\"

Gulf of Mexico moisture will surge north into Arkansas with a developing storm system leading to heavy rain and potential for some severe thunderstorms in TX/LA/AR.

HRRR simulated radar | Next 48-hours through Friday afternoon

\"\"

NWS | Total Precipitation Next 48-hours

\"\"

Large area of 1-2\u201d centered upon Louisiana and Arkansas. A lot more \u2014 6-8\u201d along the CA/OR/WA coastline.

NWS | Total Snowfall Next 48-hours

\"\"

Nice to see the Pacific moisture going to good use for snowfall across the Western U.S. in the Rockies even with much above normal temperatures.

Nor\u2019easter that goes to waste?

\"\"

The HRES shows the storm system developing off New England but in a \u2018too warm\u2019 air mass for a blizzard. The ensembles show a low pressure collection late Wednesday suggesting high confidence in storm development \u2014 regardless of the snowfall. Colder air behind the storm will allow for Lake Effect snowfall, of course.

\"\"
\"\"

Atmospheric Rivers | Next 10-days

\"\"

4 more atmospheric rivers for the U.S. West Coast.

But, also note significant moisture plumes off the U.S. East Coast with developing storm systems. No shortage of moisture, but certainly not enough cold air.

Weather Trader is a reader-supported daily weather newsletter focusing on the United States, the tropics, and interesting news. Consider upgrading to a paid ($5/month) subscription to receive all new posts into 2025.

January 2025 begins with Eastern U.S. Troughing

\"\"

I don\u2019t think anyone who wants winter weather can complain about the pattern shift through the first week of January 2025 with troughs digging into the Eastern U.S. and persisting. However, compared to \u201cnormal\u201d the coldest air might be in the Southeast e.g. January 3 (my birthday)

ECMWF AIFS

\"\"

ECMWF EPS Ensemble Mean

\"\"

Thursday Morning Temperatures

\"\"
\"\"

114 million at/below freezing \u2026 with coldest temperatures still in New England.

Thursday High Temperatures

\"\"

50s creeping into Indianapolis and Columbus, Ohio. 60s into Nashville. However, easterly winds with the Appalachian wedge will keep Atlanta and the Carolinas cooler than otherwise in the low-50s.

6:15 PM ET Temperatures across the Lower 48

\"\"

Temperature Anomaly | 6:15 PM ET

\"\"

Overall the Lower 48 is 5.1\u00b0F (above normal).

Total Precipitation next 7-Days | NOAA WPC

\"\"

Very wet pattern for Eastern U.S. for late December. Boatloads for Pacific Northwest.

7-day Ensemble Median Snowfall

\"\"

Plenty of mountain snow \u2026 and almost nothing east of the Rockies.

15-Days Ensemble Median Snowfall

\"\"

We need to look past the next 7 days for winter weather to return across the eastern 2/3 of the Lower 48. The median of the ensemble won\u2019t show extreme events e.g. if less than 50% chance of snowfall of any accumulation on this map.

So, we look at the probabilities out of the 50-ensembles (2% for each)

Probability of 1\u201d or 3\u201d+ Snowfall Next 15-days

Starting to see 10-20% chances of at least 1-inch of snow creeping into Atlanta and the Carolinas.

Zooming out to the entire Lower 48 for 1-inch

\"\"

But for powerful winter storms e.g. blizzards, we need to look at higher snowfall totals.

Probability of 6\u201d or more

\"\"

Not surprising to see the lack of a coherent signal for winter storms / Nor\u2019easters when the first 7-10 days are blank. In other words, too soon to say much about storm tracks in the long range aside from noticing the upper-level pattern (c.f. 500 mb ensemble height anomaly) looks favorable for lows to develop off the East Coast.

ECMWF EPS 12z | 5-Day Chunk Temperature Anomaly

Days 1-5: December 25 - December 29

\"\"

Days 6-10: December 30 - January 3

\"\"

Days 11-15: January 4 - January 8

\"\"

Significant cold anomaly across Eastern U.S. with [relative] warmth out west.

Snowfall Analysis | Season to Date October 1, 2024 \u2014 today

\"\"

Snowfall Last 7-Days

\"\"

Maps sourced from weathermodels.com designed and innovated by yours truly! Please subscribe there for real-time access to the newest maps, charts from all of the weather models including ECMWF.

", "body_key": null, "teaser_html": "

Today\u2019s weather was mostly quiet except for the Pacific Northwest. A warmer and wetter pattern takes over for the next 4-5 days before a subtle pattern shift allows colder Canadian continental air to flood into the Eastern U.S.

By next Wednesday, a potential Nor\u2019easter could develop but looks like mostly rain with temperatures too warm for significant snow. However, the low tracks into Canada and stalls out \u2014 its circulation allows NW winds to drag Arctic air all the way into the Southeast by the following weekend. This is a Day 7-10 time period event, so way down the road.

", "claims": [], "assets": [], "provenance": { "built_at": "2026-09-10T14:46:15Z", "model": null, "cycle": null, "stores": [ "https://weather.substack.com/p/december-25-2024-wednesday-winter" ], "mint_sha256": null, "pairing_rule": null, "detector": null, "detector_version": null, "inputs": { "substack_post_id": "153620471.december-25-2024-wednesday-winter", "audience": "everyone", "type": "newsletter", "imported_from": "substack export" } }, "strength": 0.0, "tags": [ "archive", "everyone" ], "supersedes": null, "superseded_by": null, "source": "substack", "canonical": "https://weather.substack.com/p/december-25-2024-wednesday-winter", "slug": "december-25-2024-wednesday-winter-weather", "path": "/mp/471/", "url": "https://forecastpost.com/mp/471/", "desk_label": "Winter", "digest": "8740b0fc47045f6903df2b665a801b07156639a78b409777260491b753d24a65" }