MUWIC Newsletter - March 2006

(Issued: March 2, 2006)

Millersville University Weather Information Center (MUWIC)

Eric J. Horst, Director

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LEAD STORY: A Winter of Extremes

Variability is a hallmark of Pennsylvania winters, with most years producing several measurable snowfalls and a couple of notable warm spells. But no winter on record here has juxtaposed such an early season arctic outbreak with a month-long January Thaw. Winter commenced with three frigid weeks that averaged over 8 degrees below normal and produced almost twice the normal snowfall for December. The chill bottomed out with a record low of 0 F on December 14^th—the earliest zero-degree reading in the 91 years of Lancaster climatology.

The arctic air eventually mellowed during the final week of December, and this moderating trend soon gave way to a five-week January Thaw. Although no record highs were established, temperatures did reach the 60s six times in January. Even more remarkable was the lack of snow, as nothing more than a few flurries fell the entire month. This is just the fourth January on record with no measurable snow.

Winter weather finally made a comeback in February with increasing chill as the month progressed. This return to seasonably cold conditions was punctuated by a major Nor’easter on February 12^th. Snowfall ranged from ten to twenty inches across the county, while parts of southern New England received a bonafide blizzard.

Dates Duration Depart. from Norm Snowfall

December 1 – 21, 2005 21 days -8.2 8.4

Dec. 22 – February 7, 2006 48 days +8.5 Trace

February 8 – 28, 2006 21 days -2.5 15”

March 1 - 9, 2005 9 days -5.0 (estimate) ??

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STAT OF THE MONTH

Despite above normal snowfall in December and February, mid-winter featured a near-record snow drought. No measurable snow fell between December 16^th and February 10^th. This fifty-seven day no-snow streak is the fourth longest wait between winter storms (77 days, 1973)

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FEBRUARY CLIMATOLOGY (MU Weather Station)

Average High Temp: 41.5 F

Average Low Temp: 24.5 F

Average Monthly Temp: 33.0 F

(Departure from Normal: +0.4F)

Snowfall: 15.0 inches

(Departure from Normal: +6.8)

Total Precipitation (liquid equivalent): 2.30 inches

(Departure from Normal: -0.17)

Annual Precipitation: 5.96 inches

(Departure from Normal: +0.48)

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MARCH NORMALS, RECORDS & FACTS

Normal high/low temperatures increase rapidly from 46/26 on March 1st to 59/36 on the 31st. The record high for March is 88 degrees (1921, 1945) and the record low is –1 F (1984). Normal liquid precipitation (rain and melted snow) is 3.38 inches. Average snowfall for the month is 3.7 inches. Spring officially arrives at 1:26 p.m. on March 20^th.

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MARCH OUTLOOK

March is beginning with a massive jet stream block over Greenland, which has displaced the polar vortex into Quebec and northern New England. (This is a classic negative NAO configuration.) The result will be a continuation of below normal conditions through about March 10^th. Beyond this, the block looks to break down and a significant warming trend may begin. Next week could then be the final round of arctic chill and the last chance for a winter storm in the Lancaster area.

Meanwhile, a powerful Pacific jet will continue to send storms into the west coast every few days. As these Pacific systems work east of the Rockies, unseasonable warmth will grow in the Plains and then attempt to expand to the East coast. As long as the Greenland block (–NAO) remains in place, the war air will fail to take hold over the Northeast. However, with the demise of the block likely by mid-month, I do see a period of Spring-like conditions sometime between March 11^th and 20^th.

Still, I’m not ruling out the return of a blocky pattern in late March or early April. In fact, it’s my sense that we will see the negative NAO configuration return sometime after the Equinox (March 20). This would lead to a period of below-normal conditions and a good chance of a cold rainstorm (locally) with late-season mountain snowfall (above 1,500 feet).