MUWIC Newsletter - April 2007

(Issued: April 2, 2007)

Millersville University Weather Information Center (MUWIC)

Eric J. Horst, Director

************************************************************************

LEAD STORY: “Manic March!”

March typically produces a wide range of weather conditions across the Commonwealth, but this year was especially manic. March began as February ended, with unseasonably cold conditions and a couple of inches of snow during the first week, and a record low temperature of 4 degrees on March 8^th. A dramatic warm up followed with high temperatures peaking at a balmy 79 degrees on March 14^th. Just thirty-six hours after this near-record high, a late-winter storm dropped 7 inches of snow and sleet on the county. Several unseasonably cold days followed this storm, before a major warm-up pushed temperatures to a high of 81 degrees on March 27^th. Whew!

Interestingly, March’s wild ride resulted in a statistical wash for monthly temperatures. The occurrence of above and below normal days was almost even (13 above and 12 below), and the monthly average temperature was just one-tenth of a degree below normal. Precipitation-wise, the month concluded about a quarter-inch above normal; however the month’s snowfall was more than double the long-term average at 9.6 inches.

************************************************************************

EVENT OF THE MONTH

A mid-month Nor’easter dropped 7 inches of snow (and sleet) in the Millersville area and up to 10 inches in the northwestern quarter of Lancaster county. More than a foot of snow fell in northeastern PA, while parts of interior New England received nearly two feet of snow!

************************************************************************

MARCH CLIMATOLOGY

Average High Temp: 51.5 F

Average Low Temp: 31.0 F

Average Monthly Temp: 41.3 F

(Departure from Normal: -0.1 F)

Snowfall: 9.6 in.

(Departure from Normal: +5.2 in.)

Precipitation: 3.66 inches

(Departure from Normal: +0.28)

Annual Precipitation: 8.39 inches

(Departure from Normal: -0.47)

************************************************************************

APRIL NORMALS, RECORDS & FACTS

Normal high/low temperatures range from 59/37 on April 1st to 70/44 by month's end. The record high for April is 95 degrees (on 4/18/76) and the record low is 11 F (on 4/1/23). Normal liquid precipitation (rain and melted snow) is 3.47 inches. Measurable snow falls in April on an average of once every five years. The rainiest April on record occurred in 1983 (9.14 inches) while the driest April was just two years later (0.39 inches in 1985).

************************************************************************

APRIL OUTLOOK

The first half of April will continue the manic ways of March as temperatures swing more than 50 degrees over the first week of the month. Unseasonable warmth will rule through midday of April 4^th, however a major pattern change will produce a dramatic drop in temperatures in the days that follow. The period April 5^th through 9^th looks somewhat unsettled and unseasonably cold as a large upper-level low closes off over eastern Canada. This will direct northwest winds and a steady delivery of continental polar air into the Great Lakes and Northeast. Lake effect snow showers will fly one more time across the higher terrain of Northeast, and a flurry or some graupel is even possible here in the Lancaster area. Daytime highs will struggle to reach the low to mid 40s into the weekend, and overnight lows will drop into the upper 20s and low 30s.

A moderating trend should begin around April 10^th or 11^th, and this will yield a return to more seasonable conditions by the second weekend of the month. A progressive, zonal pattern looks to set up into mid- and late-month. If so, the overall pattern may become less extreme, but with frequent opportunities for April showers and occasionally cool days. In the end, the month may conclude very close to normal, both in terms of temperatures and precipitation.