{ "number": 815, "headline": "December 14, 2025 Sunday Evening Winter Weather", "standfirst": "Warming trend this week with main storm track staying in Canada", "desk": "winter", "dateline": { "place": "Weather Trader", "state": null, "lat": null, "lon": null, "site_key": null, "site_name": null, "site_url": null, "accent": null }, "edition": "2025-12-15", "published": "2025-12-15T02:29:07.841000Z", "updated": null, "access": "free", "body_html": "
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This is post number 815: Good Evening!

Author: Dr. Ryan Maue (X @RyanMaue X @weathertrader)

Observed Snowfall Last 7-Days

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As snowfall reports come in \u2014 model data and radar indicated precipitation is merged together into the optimal estimate of \u201csnowfall\u201d \u2014 which is somewhat different than what may be measured on the ground 6-12 hours later due to compaction. I saw 0.5\u201d of QPF at NYC but only 2.7\u201d of snowfall recorded in Central Park. Regardless, in meteorology, when you take an observation at a point, you cannot say much else about neighboring locations due to representativeness in time and space. When a weather balloon is launched, it is measuring the atmosphere at that time and along the trajectory of the balloon, not 3-hours later.

In general, our QPF forecasts are pretty good \u2014 but snowfall error creeps in with the snow-to-liquid ratios (SLR) or the fluff factor dependent upon the temperature of the lowest layers of the column above the surface. I think we did pretty well with the \u201cjackpots\u201d in central coastal New Jersey.

Still the entire \u201cwinter\u201d lies ahead \u2014 so don\u2019t be too concerned about the warm-up on the way into Christmas. We actually need to thaw out a little bit for the economy \u2014> shopping and travel.

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HRRR 18z | Next 48-Hours through Tuesday 7 AM ET

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Once the Nor\u2019easter moves away, all that remains is brutally cold air for another morning or two across the Great Lakes and Northeast \u2014> Lake Effect snow machine.

Another storm system (atmospheric river) crashes into the Pacific Northwest \u2014 just the next one in a long parade of storm systems that cruise across southern Canada

Storm System Parade Across Canada | Next 6-days

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Multiple impressive storms cross Canada \u2014 with pressure in the 970s or 980s but remain north of the U.S. border and work with a much warmer air mass to the south \u2014 within the growing mid-level ridge. The main \u201cPolar Vortex\u201d retracts into Canada and only minor excursions or lobes will be affecting the Lower 48 for the coming 10-14 days. However, even with the PV locked up (mostly) there is still opportunity for brief mini-Arctic blasts for a day or two as part of these powerful storm systems.

Precipitation Type | Weather Next 6-days | ECMWF 18z

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Headlines Sunday Evening

  1. Storm system moves away from Northeast \u2014 cold air behind it.

  2. Significant warming trend into upcoming week \u2014 finally. It can\u2019t stay cold forever.

  3. However, as the ridge builds across the Lower 48 from coast-to-coast into Christmas, we still will need to deal with a few bouts of Arctic air in the Great Lakes and Northeast \u2014 so not exactly \u201cshorts and t-shirt\u201d for Santa Claus, just not brutally cold \u2014 like this weekend.

Warm Up on the Way \u2014 Briefly Interrupted Friday

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There is a MASSIVE Alaska / West Canada cold pool that is continually replenishing due to offshore flow from interior Arctic environs \u2026 circulation around a strong Aleutian Low spinning in the Gulf of Alaska. Typically this air can flood southward down the U.S. West Coast with troughs, but that avenue is foreclosed due to the honking ridge blocking its escape. So, the cold air looks for opportunity with passing storm systems to hitch a ride across the continent.

Storms Will Have a LOT of Wind Energy | Friday Morning

Will talk more about these powerful storms on Monday \u2026 but we\u2019re in for some huge wind makers in the Northeast \u2026 example here is a 975 mb low pressure over Quebec ahead of a Polar Vortex lobe \u2014> which has access to some of that Canadian Arctic cold pool.

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High Temperatures Next 8-days | Until Tuesday, Dec 23rd

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Warming trend after Monday \u2014 well deserved after an abnormally very cold start to December.

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ECMWF 18z Precipitable Water Next 6-days | My favorite parameter

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ECMWF 12z | Temperature Anomaly | Next 15-days

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Flagship European model ensemble solution for temperature anomaly next 15-days

The Lower 48 settles into a \u201cBlow Torch\u201d much above normal temperature pattern \u2014 eventually \u2014 once we can finally block off the \u201cpolar vortex\u201d by this next weekend.

Temperatures surge to well above normal for much/all of the Lower by Christmas \u2014 BUT still some uncertainty about the Great Lakes and Northeast \u2014 especially with proximity to the \u201cPolar Vortex\u201d and any lobes that may be dragged south by passing storm systems.

RTMA | 24 Hour Temperature Change | 7:45 PM ET

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Temperatures upwards of 37\u00b0F colder from Texas to Mid-Atlantic, including Atlanta.

RTMA | Current Temperature Analysis | 7:45 PM ET

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Average Lower 48 temperature was 31.7\u00b0F with about 189 million below freezing.

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About 5 million population below 0\u00b0F

Temperature Anomaly | 7:45 PM ET

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Lower 48 Temperature Anomaly was -5.2\u00b0F BELOW normal

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Coldest temperatures in the 35\u00b0F to 45\u00b0F below normal range in central Illinois

Monday Low Temperatures

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More than 230 million below freezing but only 13 million subzero \u2014 so \u201ccould be a lot worse\u201d for sure \u2014 but it\u2019s only Mid-December.

Teens into Alabama, Mississippi, and North Georgia. Atlanta may only escape in the low-20s at the airport. 20s into North Florida = frigid.

Monday High Temperatures

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Improvement \u2014 slightly. We\u2019ll start the warmup from a chilly baseline in the Great Lakes only in the 20s.

Tuesday High Temperatures

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Much warmer \u2014 add another 10\u00b0F across the board east of the Rockies

NWS Precipitation Next 72-hours

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NWS Snowfall Next 72-hours

Blend of Models | 7 Days Precipitation Total

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Enormous rainfall totals across the Pacific Northwest continue for next 7-days at least.

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Blend of Models | Total Snowfall Next 7-Days

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ECMWF AIFS-Single 18z | Height Anomaly (500 hPa) Next 10-days

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One more \u201cpolar vortex\u201d trough into this upcoming weekend \u2014 Days 6-8 \u2026 and then the ridge builds across the Rocky Mountains and forms a long-lasting block.

No doubt about the intensity of this Lower 48 Blocking Ridge \u2014 so we next must determine when this pattern \u201cbreaks down\u201d and we shake the bag, spin the wheel, or whatever to determine where the overall upper-level patterns goes into the weekend after Christmas

Day 10 EPS Full Physics ECMWF 12z | EPS Ensemble Mean and Control

Day 10 AIFS Ensemble Mean + AIFS Single

ECMWF 12z | Integrated Vapor Transport Next 10-days

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Parameter used for monitoring \u201catmospheric rivers\u201d usually along the U.S. west coast, but the idea works well for many other areas \u2014 highlighting midlatitude storm systems with warm conveyor belts (moisture plumes)

ECMWF 18z | Snowfall | Next 6-days

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ECMWF EPS 12z | Ensemble Median Snowfall Next 15-days

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Next 15-days Temperature Anomaly | Ensemble Mean to December 28

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Temperature Anomaly | Next 15-days | ECMWF EPS 12z

5-Day Chunk #1 | Temperature Anomaly | Dec 14 - Dec 18

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5-Day Chunk #2 | Temperature Anomaly | Dec 19 - Dec 23

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5-Day Chunk #3 | Temperature Anomaly | Dec 24 - Dec 28

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The Northeast well below normal (?)

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

As snowfall reports come in \u2014 model data and radar indicated precipitation is merged together into the optimal estimate of \u201csnowfall\u201d \u2014 which is somewhat different than what may be measured on the ground 6-12 hours later due to compaction. I saw 0.5\u201d of QPF at NYC but only 2.7\u201d of snowfall recorded in Central Park. Regardless, in meteorology, when you take an observation at a point, you cannot say much else about neighboring locations due to representativeness in time and space. When a weather balloon is launched, it is measuring the atmosphere at that time and along the trajectory of the balloon, not 3-hours later.

In general, our QPF forecasts are pretty good \u2014 but snowfall error creeps in with the snow-to-liquid ratios (SLR) or the fluff factor dependent upon the temperature of the lowest layers of the column above the surface. I think we did pretty well with the \u201cjackpots\u201d in central coastal New Jersey.

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