MUWIC Newsletter - November 2003

(Issued: November 3, 2003)

Millersville University Weather Information Center (MUWIC)

Eric J. Horst, Director

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LEAD STORY: “October Surprise: Frosty Start Gives Way to Mild Finish”

October began frosty with the earliest freeze—and end of growing season—since 1993. Low temperatures dropped to 32F on the morning of October 3^rd, and it has not been this cold so early in the season since our low of 32F on October 1, 1993 (see Table below). The normal date of first freeze is October 13^th.

Interestingly, the much below normal first week of October did not lead to a below normal classification for the month overall. Two notable spells of Indian Summer developed, and the second occurrence has turned into the record-breaking warmth of early November. October 2003 averaged out at just over a degree below normal, which is within the “normal” classification defined by long-term climatology.

So, what do these trends mean regarding the winter ahead? Not much. Historically, near-normal Octobers are followed by a nearly equal number of above- and below-normal winters. Should the current warm spell linger into late November, however, it would likely lead to a warm beginning to the winter. I’ll have more on this in my Winter Outlook, to be issued in next month’s newsletter.

DATE OF FIRST FREEZE (and low temperature)

10/3/03 – 32F

10/15/02 – 32F

10/8/01 – 32F

11/7/00 – 32F

11/5/99 – 30F

11/4/98 – 31F

10/23/97 – 32F

10/5/96 – 29F

10/26/95 – 32F

10/6/94 – 32F

10/1/93 – 32F

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EVENT OF THE MONTH

On October 14^th, a narrow cold-frontal rainband dropped over an inch of rain in just three hours (8:00pm to 11:00pm). This downpour produced some minor flooding.

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OCTOBER CLIMATOLOGY (MU Weather Station)

Average High Temp: 62.6 F

Average Low Temp: 42.6 F

Average Monthly Temp: 52.6 F

(Departure from Normal: -1.3 F)

Precipitation: 3.71 inches

(Departure from Normal: +0.71)

Annual Precipitation: 41.13 inches

(Departure from Normal: +6.24)

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NOVEMBER NORMALS, RECORDS & FACTS

November features the largest beginning-to-end drop in normal temperatures. The month begins with pleasant average high/low temperatures of 60/38, but ends with much more winter-like normals of 46/28. Average rainfall for the month is 3.53 inches, while average snowfall is about one inch. Measurable snow occurs roughly once every four years. Extremes: Record high - 84 on 11/2/82; Record low - 1 on 11/29/38; Wettest November - 8.05" in 1972; Driest November - 0.58" in 1931 & 1938.

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NOVEMBER OUTLOOK

I’ll begin with the obvious—November will start off unseasonably warm. The first five days of the month will average more than 15 degrees above normal. Given this near-record warmth, weather conditions for the remainder of November can only go one way.

Two cold fronts will cross the region later this week, bringing to an end the Indian Summer conditions. The first front moves through late on the 5^th and will drop temperatures to near-normal levels for week’s end. A second, stronger front should arrive Friday night and usher in an unseasonably chilly airmass for the weekend. Temperatures from the 8^th through the 10th should average about 5 degrees below normal. Thus, the magnitude and length of this cold snap will not come close to equaling that of the current warm spell.

From mid-November onward, I foresee a return to the progressive pattern we experienced in October. I do believe we’ll see a few two- or three-day visits of chilly Canadian high pressure systems. However, I also believe that zonal upper-level flow and, at times, a bonafide southern branch of the jet stream will produce a few notable warm-ups. The big question relates to whether this zonal branch of the jet stream will be active with Pacific storms. If so, the second half of the month could turn wet (or white).

In the end, I believe the early heat wave will not be equaled in terms of late-month chill. Therefore, I expect November will end a few degrees above normal in aggregate. Precipitation is a tougher call, so “near normal” is the best play.