MUWIC Newsletter - September 2002

(Issued: September 3, 2002)

Millersville University Weather Information Center (MUWIC)

Eric J. Horst, Director

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LEAD STORY: "Late-summer Heat Worsens Drought"

Summer 2002 was not the warmest or the driest summer on record (1966 holds these distinctions), but an extended spell of late summer heat did produce an amazing thirty-four 90-degree (or above) days over just a seven-week period. Worse yet, less than 1.5 inches of rain fell during this seven-week period, driving the region into its worst long-term drought on record.

Despite more frequent rains in recent days, the magnitude of the drought increased dramatically during the summer months. The rainfall deficit since the onset of the drought (November 2000) has grown to over 33 inches, and we will need to receive about a third of this total, in the short-term, to end the drought. Of course, such heavy rains are unlikely during the fall season--short of having a tropical storm move over the region--and, therefore, the Drought Emergency may well continue into the winter season.

Temperature Statistics (MU Weather Station):

Normal Actual Monthly Temp.

# of 90s # of 90s Departure from Norm.

April 0.5 3 + 3.0

May 1.5 0 - 1.0

June 5 6 + 2.3

July 9 18 + 3.4

August 6 16 + 5.5

September 2 *

Total 24 43 + 3.7 (June - August)

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EVENT OF THE MONTH

On July 2nd, temperatures topped the century mark with a high of 101F. This high temperature tied the record for the date set in 1955.

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AUGUST CLIMATOLOGY (MU Weather Station)

Average High Temp: 88.8 F

Average Low Temp: 67.2 F

Average Monthly Temp: 78.0 F

(Departure from Normal: + 5.5 F)

Precipitation: 2.16 inches

(Departure from Normal: -1.81)

Annual Precipitation: 17.61 inches

(Departure from Normal: -10.7)

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SEPTEMBER NORMALS, RECORDS & FACTS

Fall officially arrives at 12:56 a.m. on the 23rd (autumnal equinox). Normal rainfall for September is 3.62 inches, and normal high and low temperatures range from 82/59 (high/low) on the 1st to 71/47 on the 30th. On average, there are eight days with measurable precipitation (third lowest monthly average) and two days with a high temperature of 90F or above. The record high for September is 99F (9/3/53) and the record low is 27F (9/26/22).

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SEPTEMBER OUTLOOK

The cool, damp start to September will hopefully be a harbinger of things to come. Looking at the weather maps, however, I just don't see much hope for further soaking rains any time soon. A large jet stream ridge is in place over the central US, and a series of high-pressure systems will dominate our weather through mid-month. The only chance of showers will likely come with passing fronts every few days; though, during the late Summer and Fall such fronts tend to underperform.

Therefore, we must continue to look to the tropics as a source of drought-busting rains. The next eight weeks are the heart of hurricane season, and there undoubtedly will be several named storms in the coming weeks. Whether or not any of these systems wanders up the east coast is much less certain. In September 1999, the remains of Hurricane Floyd brought a half-foot of rain to our region, but the last two seasons have not brought any significant tropical rains. So, it might be that we are due such a rainstorm sometime this fall...

Temperature-wise, I see no reason to go against the trend of past months-that is, temperatures will average somewhat above normal for September. Though, the risk of sustained heat waves is gone, I do expect several spells of warmer-than-normal conditions with highs in the 80s. Surely, cooler air will filter in later this month--Fall begins on September 23rd--but in the end, I expect the month as a whole to total a couple degrees above normal.