January 2019: Mild and wet, sub-par snowfall

January’s first week began on a mild note, exactly opposite from the extreme cold of one year ago. The mild pattern would shift into a see-saw temperature pattern for the remainder of the month. Melted precipitation was above normal, while snowfall was below normal.

Temperatures were not very January-like during the first week of 2019, but as the polar jet stream shifted back southward, we saw a more typical see-saw temperature pattern evolve for the remainder of the month.

Temperatures averaged almost 12 degrees above normal per day for the first six days of the month, then polar air returned to the Northeast bringing back the chill we’re all familiar with at this time of year. Just a year ago, we suffered through severe cold through the first week of January, followed by significant moderation.

The 2019 version of January went in the opposite direction of last year, with periods of colder than normal readings after the first week. A brief punch of severe cold would blast through the Gate City on Jan. 21, when temperatures remained only a few degrees above zero all day, accompanied by gusty winds creating bone chilling wind chills.

This punch of cold air was a result of a piece of the polar vortex making a journey across the Great Lakes to New England before retreating into eastern Canada. The term “polar vortex” is term meteorologists have been using for many decades. The mass media misuses the term due to lack of understanding of what it is.

A polar vortex is an expansive upper low that makes a home across the North and South Poles of the planet. This low strengthens and expands during the winter and weakens and contracts during the summer helping to create our seasons.

Once is a while, the polar vortex can be broken up into two or three centers that can then cycle southward into a mean trough position bringing severe cold to the mid latitudes where we live.

During times when the polar vortex is all together near the pole, it still produces cold air that is cycled southward behind departing low pressure areas bringing us cold, windy days during the winter and pleasantly cool, dry air in summer. The broken up pieces of the polar vortex tend to bring the severely cold periods.

The average temperature for January was 24.9 degrees, 2.2 degrees above normal. January ranked in a tie for 45th warmest out of 126 years of temperature records. The high for the month of 55 degrees occurred on Jan. 24, just a few days after readings struggled to stay above zero all day.

The coldest daily temperature departure was observed on Jan. 22, when readings averaged 19 degrees below normal. Just three days later, the average temperature was 19 degrees above normal.

A record low high temperature was recorded on Jan. 22, with 6 degrees. This breaks the mark of 10 degrees set in 2005. All 31 days saw low temperatures at or below freezing, one more than normal, and 14 days failed to rise above freezing, which is right on the normal.

Going from one extreme to another is rather common with weather. The wave pattern around the globe progresses along, bringing changeable weather in the mid latitudes. If the amplitude of the waves is large, we can then see the large change from very cold to very warm in a short time frame.

The percent of possible sun recorded at the Blue Hill Observatory in Milton, Massachusetts, was 53 percent, seven percent above normal.

Precipitation totaled 4.78 inches during January, 1.36 inches above normal. January ranked as the 22nd wettest January out of 136 years of records. The largest precipitation event was all rain from Jan. 23 into Jan. 24, resulting in 1.6 inches of rain.

A few days earlier, we saw 1.29 inches melted, which was snow and sleet. Several other small events brought the city the remainder of the January total.

Snowfall totaled 13.0 inches last month, 3.5 inches below normal. After a couple minimal amounts early in the month, Nashua saw its largest snow event from Jan. 20 into Jan. 21, with 8 inches.

January’s snowfall ranked at No. 46 out of 110 years of snowfall records for Nashua from least to greatest.

The season total of 20.9 inches is 9.3 inches below normal for the end of January. Few of the past 25 seasons have seen below normal snowfall, which makes it seem like we’ve had an unusually low amount this winter.

The northern third of New England is having a rather snowy winter this year. Caribou, Maine, saw its snowiest January of record with nearly 60 inches. Their season total of 112 inches is already 4 inches above the normal for an entire season.

Just last winter, snowfall was below normal at the end of February, and we ended up well above normal for the season. It’s a case of not counting your chickens before they hatch.

We’re past the mid-point of winter, and daylight already has increased by more than an hour since late December, and we gain another hour before February comes to a close. Normal temperatures have been on the rise for a couple weeks now, and the normal high reaches 40 by month’s end.

Despite the increase in day length and temperature, February can play host to some of the fiercest snowstorms and coldest temperatures on record. Six years ago, Nashua saw its’ second-largest February storm with 24.0 inches. On Feb. 16, 1943, the mercury fell to -35 in Nashua, the coldest day on record for the city.

February 2015 was the coldest month on record for Nashua and came with 44 inches of snow. Who can forget the Blizzard of 1978, which is the real perfect storm. It will be spring sooner than you think, and in just a few months we’ll be complaining about the heat and humidity all over again.

January Facts

Dating Back to 1884

January 2019 average temperature

24.9, 2.2 degrees above normal

Mildest January

34.5, 1913

Coldest January

12.9, 1888

All-time January high

69, Jan.7, 2007

January 2019 high

55, Jan. 25

All-time January low

-29, Jan. 18, 1957

January 2019 low

-2, Jan. 31

January 2019 precipitation

4.78 inches, 1.36 inches above normal

Wettest January

10.50 inches, 1979

Driest January

0.60 inches, 1980

January 2019 snowfall

13.0 inches, 3.5 inches below normal

Snowiest January

1987, 46.5 inches

Least snowy January

2007, 0.3 inches

2018-19 season snowfall

20.9 inches, 9.3 inches below normal