MUWIC Newsletter - January 2004

(Issued: January 6, 2004)

Millersville University Weather Information Center (MUWIC)

Eric J. Horst, Director

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LEAD STORY: “Wettest Year Since 1996”

A persistent storm track the last 15 months has completely erased the record drought of summer 2002. In fact, rainfall the last twelve months made 2003 the eleventh wettest year on record in Lancaster. The 49.86 inches measured here at the MU Weather Center is the greatest annual total since the 1996. View the entire 89-year rainfall database at: http://www.atmos.millersville.edu/~cws/climo/p-anomaly.htm

Year Total Rainfall (inches)

1996 59.05 *

1997 29.79

1998 38.31

1999 40.49

2000 34.74

2001 22.68 #

2002 33.77

2003 49.86

(*) indicates the wettest year on record

(#) indicates the driest year on record

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EVENTS OF THE MONTH

For the second year in a row, an eight-inch snowstorm hit the area on December 5^th. This one event dropped more than the average monthly snowfall for December (4.6”).

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STAT OF THE MONTH

The first three weeks of December were unseasonably cold with temperatures averaging about 3.8 degrees below normal. The last 10 days of the month, however, turned unseasonably warm with an average temperature anomaly of 8.2 degrees above normal. In aggregate, December finished up “normal” with no temperature anomaly. This highlights how statistics don't always tell the true climatological story.

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DECEMBER CLIMATOLOGY (MU Weather Station)

Average High Temp: 42.2 F

Average Low Temp: 25.8 F

Average Monthly Temp: 34.0 F

(Departure from Normal: 0 F)

Snowfall: 10.2 inches

(Departure from Normal: +5.6 inches)

Total Precipitation: 4.24 inches

(Departure from Normal: +1.26)

Annual Precipitation: 49.86 inches

(Departure from Normal: +8.80)

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JANUARY NORMALS, RECORDS & FACTS

Normal high/low temperatures for January are 39/22, respectively. The record high for the month is 77 degrees (January 27, 1950) and the record low is -18 (January 21, 1994). Normal liquid precipitation (rain and melted snow) is 3.01 inches. Average snowfall for the month is 8 inches.

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JANUARY OUTLOOK

Winter got off to a quick start with two snowstorms in the first half of December. Since then, however, there has been a lack of cold air and no significant snow threats. In fact, as recently as January 3^rd temperatures soared to within two degrees of tying the record high (64F). So, what’s happened to winter? Is it over?

Not even close! As I write this newsletter (January 5^th) a massive arctic blast is entering the United States. Temperatures will drop to near 20 below zero in the northern plains, and I expect we’ll see a zero-degree reading somewhere in northern PA by week’s end. Locally, temperatures will plummet to the coldest levels of the season with highs in the mid 20s and lows approaching 10 degrees by January 8^th. A dramatic realignment of the jet stream pattern is responsible for the sharp turn to colder weather, as deep northwest wind flow ushers arctic air our way. Given this pattern, though, it’s unlikely any major storms will form in the short term. Still, a couple of weak disturbances could brush us with a little light snow or flurries around the January 9^th and 11^th or 12^th.

Heading into mid-month, I don’t see any changes—that is, no flip-flop back toward much above normal temperatures. High latitude blocking over Alaska may force Siberian air to cross the north pole and drop into Canada by early next week. If so, an even colder blast of air could arrive hear sometime form January 13^th to 17^th. Even if this secondary surge doesn’t arrive, we will at best see temperatures returning to near normal levels by mid-month. We’ll need to keep an eye on the Pacific for future storminess moving into the west coast that might eventually bring a winter storm to the East. If extreme cold hangs tough in the east, however, it would tend to suppress the storm track and prevent a big storm.

In summary, I expect temperatures for the rest of January to average normal to below normal. Total precipitation may also be below normal, but I suspect we will see at least two measurable snowfalls before month’s end.