Early January 2025 Weather Predictions

According to the “U.S. Hazards Outlook” from the National Weather Service Climate Prediction Center, released January 1, 2025, the outlook for Thursday, January 9 through Wednesday, January 15, is the following: Multiple model ensembles depict deep mid-level low pressure over the eastern Contiguous U.S. (CONUS) throughout the week-two period, as well as strong mid-level high pressure over the western CONUS and Greenland, setting up a blocking pattern that is favored to funnel Arctic air into the Lower 48 east of the Rockies with high chances for hazardous cold conditions, as well as the potential for heavy snow for the Great Lakes region as well as portions of the Southern Plains across to the Mid-Atlantic region. Strong surface low pressure over the Bering Sea is favored to produce high winds and heavy precipitation for the southern coast of Alaska.

Hazards In Specific

1 – High risk of much below-normal temperatures for much of the Southeastern U.S. and portions of the Lower Mississippi and Tennessee Valleys, Thu-Sat, Jan 9-11.

2 – Moderate risk of much below-normal temperatures for the Southeastern U.S., Tennessee and Ohio Valleys, and the Appalachians, as well as much of the Mid-Atlantic, and Lower and Middle Mississippi Valley, and portions of the Great Lakes, and Central and Southern Plains, Thu-Sun, Jan 9-12.

3 – Slight risk of much below-normal temperatures for much of the central and eastern CONUS with the exception of the western Great Plains and the Northeast U.S., Thu-Tue, Jan 9-14.

4 – Slight risk of heavy snow downwind of Lakes Erie and Ontario and along the Allegheny Front, Thu-Mon, Jan 9-13.

5 – Slight risk of heavy snow for much of the Tennessee Valley as well as portions of the Mid-Atlantic, Southeastern U.S., Lower and Middle Mississippi Valley, and Southern Plains, Thu-Fri, Jan 9-10.

6 – Slight risk of heavy snow for portions of the Northern and Central Plains, Thu-Mon, Jan 9-13.

7 – Slight risk of high winds for portions of the Northern and Central Plains, Thu-Mon, Jan 9-13.

8 – Slight risk of heavy precipitation for much of the southern and southeastern coast of Alaska, Thu-Mon, Jan 9-13.

9 – Slight risk of high winds for the southern and southeastern coast of Alaska, Thu-Mon, Jan 9-13.

In terms of the “Detailed Summary” for this week: Model ensembles continue to be in very good agreement regarding depiction of a deep trough over the eastern CONUS during the week-two period, as well as amplified ridging over Greenland and the West Coast, resulting in a long fetch of northerly winds from the Canadian Arctic through much of the central and eastern CONUS leading to high potential for hazardous cold across much of the Lower 48 east of the Rockies.

Today’s model guidance favors a weakening of the blocking ridges later in week-two and a gradual moderation of the intruding Arctic airmass. Nonetheless, this is likely to be a very impactful surge of Arctic air near the peak of winter for much of the central and eastern CONUS.

The ECMWF and GEFS Probabilistic Extremes Tools (PETs) both indicate at least a 20 percent chance of low temperatures falling below the 15th percentile for Jan 9-14 for most of the CONUS east of 100W except for the Northeast U.S., as well as a widespread coverage of greater than 40 percent probabilities for Jan 9-12 over nearly the same areas as listed above (with the exception of the Upper Mississippi Valley and Great Lakes).

Additionally, a high risk (at least a 60 percent chance) of much below-normal temperatures is posted for much of the Southeastern U.S. as well as portions of the Southern Appalachians, and Tennessee and Lower Mississippi Valleys for Jan 9-11, where the PETs show the strongest signal for reaching hazardous temperatures in percentile space and where well-below freezing temperatures are very likely.

The potential for a hard freeze extends well into the Florida Peninsula, which could negatively impact citrus production in the state. In addition to the very cold temperatures, multiple models show a broad area with possibly tight pressure gradient over much of the eastern CONUS throughout the week, which could result in widespread breezy conditions and very low wind chills.

Today’s ECMWF and CMCE PETs indicate that winds speeds have at least a 20 percent chance of exceeding the 85th percentile over portions of the Northern and Central Plains, therefore a slight risk for high winds is posted for Jan 9-13, during which the PETs are in strongest agreement. In addition to the anticipated bitter cold, northerly winds from Canada and surface low pressure over the Canadian Maritimes favors increased chances for heavy snow for portions of the central and eastern CONUS through the middle of week-week.

The increased risk for heavy snow even extends into the Southern Tier early in the forecast period as a surface low is favored to track from the Southern Plains to the Mid-Atlantic, tapping into moisture off the Gulf of Mexico.

ECMWF raw ensemble snowfall totals have consistently indicated mean accumulations near two-inches, and several recent deterministic GFS runs depict heavy snowfall associated with the tracking surface low. While significant accumulations are not expected, these regions are often ill-equipped to handle snowy conditions, resulting in potentially higher impacts with lower snowfall totals. It should be noted that this southern area highlighted for the risk of heavy snow could also experience a variety of mixed precipitation types instead of all snow.

Regardless of precipitation type, a slight risk of heavy snow is posted for much of the Tennessee Valley as well as portions of the Mid-Atlantic, Southeastern U.S., Lower and Middle Mississippi Valley, and Southern Plains for Jan 9-10.

Greater snow accumulations are favored further north with favorable lake-effect snow conditions downwind of Lakes Erie and Ontario.

The GEFS PET indicates a 20 percent chance of three-day accumulated snow water equivalent (SWE) exceeding the 85th percentile, and model ensemble totals for snowfall from the ECMWF continue to depict enhanced snowfall near the Great Lakes and over the Appalachians from Jan 9-13, after which snowfall totals taper off below hazardous thresholds.

The moderate risks of heavy snow posted recently have been removed due to a combination of some of the anticipated heavy snow shifting into the week-one period, as well as lower snowfall totals indicated by ECMWF ensembles relative to previous days.

A slight risk of heavy snow has been posted for portions of the Central and Northern Plains for Jan 9-13, with passing shortwave troughs within northwest flow aloft favored to produce several rounds of snowfall. While large accumulations are not anticipated, when combined with the risk of high winds highlighted above the potential for blizzard conditions warrants including this hazard in today’s outlook. Amplified ridging over the West Coast and strong surface low pressure over the Bering Sea throughout week-two favors strong moist onshore flow into the southern coast of Alaska. The ECMWF and GEFS PETs both indicate a 20 percent chance of three-day rainfall to exceed the 85th percentile and two to three inches for much of the Alaskan coast from the Kenai Peninsula east along the coast and down through the Panhandle. Model output also indicates the potential for winds exceeding 40mph along the same stretch of Alaskan coast, although the signal for both heavy precipitation and high winds tails off towards the end of the week-two period. Therefore, slight risks of heavy precipitation and high winds are posted for Jan 9-13 for the areas highlighted above.

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