MUWIC Newsletter - October 2005

(Issued: October 3, 2005)

 

Millersville University Weather Information Center (MUWIC)

Eric J. Horst, Director

 

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LEAD STORY: "Warmest September on Record"

 

The consistently warm conditions of recent months came to a crescendo last month with the greatest departure from normal of any September on record. The average temperature for was 70.9 degrees, which is 5.9 degrees above the long-term monthly average for September. This comes on the heels of three consecutive summer months with above normal conditions. The monthly temperature anomalies for June, July, and August were +3.5, +2.4, and +4.6, respectively, making June through September the warmest four-month period on record here in Lancaster.

 

In addition to the prevailing warmth, it remained uncommonly dry throughout September. Only one inch of rain fell across the county, and this increases our year-to-date rainfall deficit to over eight inches. Meanwhile, the topics remained active with five named storms during September. View tracks of this year's storms:

http://www.wunderground.com/hurricane/images/at2005.gif

 

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EVENT OF THE MONTH

 

Hurricane Rita became the second tropical cyclone of the season to reach rare Category 5 status. This is only the third time on record that two hurricanes have achieved Cat 5 status in the same season in the Atlantic basin. 1960 and 1961 both featured two hurricanes of Cat 5 strength.

 

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STAT OF THE MONTH

 

High temperatures reached the 80-degree benchmark on each of the first twenty-three days of September. This is the longest streak of consecutive 80-degree days on record in September. The previous record was eighteen days set in 1930.

 

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SEPTEMBER CLIMATOLOGY (MU Weather Station)

 

Average High Temp: 83.0 F

Average Low Temp: 58.8 F                                                   

Average Monthly Temp: 70.9 F                                         

(Departure from Normal: + 5.9 F)

                                       

Precipitation: 1.02 inches  

(Departure from Normal: +2.60)   

Annual Precipitation: 23.84 inches              

(Departure from Normal: -8.09)

 

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OCTOBER NORMALS, RECORDS & FACTS

 

Normal rainfall for October is 3.00 inches making this the third driest month of the year.

The wettest October on record was in 1932 (8.39 inches); the driest was in 1963 when no

measurable precipitation fell. Normal high and low temperatures for October range from 71/47 (high/low) on the 1st to 61/38 on the 30th. The record high for the month is 95F (set on the 4th in 1941); the record low is 19F (set on several different days and years). Finally, Daylight Savings ends on the 30th.

 

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OCTOBER OUTLOOK

 

A guiding principle of sage forecasters is that "the trend is your friend." Thus, if it's been "warm and dry" in recent days and weeks, it would be unwise to forecast a dramatic change to cooler, wetter conditions. But that is exactly my forecast for mid-October. Yes, it currently (October 3rd) feels like late-summer outside, but I'm going out on a limb (with a saw in my hand) and forecasting a significant change beginning around October 8th.

 

September's average temperature was 5.9 degrees above normal and rainfall that was 2.6 inches below normal. Pattern modification will yield both more rainfall and cooler temperatures (relative to normal) over the next two weeks. So, while the first week of October will conclude much above normal, a new trend of near-normal conditions will develop during mid-month. I can't rule out an occasional warm day, however, I expect the period of October 8 - 31st to average out within 2 degrees of normal. Given the extremely warm first week of October, the final monthly anomaly will likely be positive--but to a lesser extent than the last two months (which were +4.6 and +5.9).

 

Quantity of precipitation during the first half of Fall is largely related to tropical influence. Assuming a few more tropical systems in October, there's a possibility of one or two soaking rains in teh coming weeks. One such event is possible October 7th or 8th, and a second event might occur between the 15th and 20th. Should these two events fail to materialize, then October would likely end up below normal on precipitation.

 

COPYRIGHT 2005 Millersville University

 

Published monthly by the Millersville University Weather Information Center.

Subscribe on our homepage at www.atmos.millersville.edu/~wic

 

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