MUWIC Newsletter - September 2006

(Issued: September 5, 2006)

Millersville University Weather Information Center (MUWIC)

Eric J. Horst, Director

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

LEAD STORY: “Warm, Dry Finish to Summer”

After the second wettest June on record, July and August turned decidedly warm and dry. In fact, late summer dryness would have pushed us back into a drought if it weren’t for the 13.34 inches of rain that fell in June. So while the soil desiccated and the grass burned out, USGS water resource monitoring shows that the rivers, reservoirs, and wells remain at near- to above-normal levels. Temperature-wise, June finished just slightly above normal, whereas July and August both placed in the top-ten warmest on record (see table), respectively.

Temp. and Precip. For Summer 2006 (Rank among 92 years)

Temp. (Rank) Precip. (DFN)

June +0.9 (31^st warmest) 13.34 (+9.46)

July +3.3 (5^th warmest) 3.34 (-1.34)

August +3.0 (10^th warmest) 1.06 (-2.91)

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

STAT OF THE MONTH

For the first 26 days, we were on track for the driest August on record. However, end-of-month showers bump up the official rainfall total to 1.09 inches, making this the 5^th driest August on record.

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

AUGUST CLIMATOLOGY (MU Weather Station)

Average High Temp: 85.2 F

Average Low Temp: 65.7 F

Average Monthly Temp: 75.5 F

(Departure from Normal: +3.0 F)

Precipitation: 1.06 inches

(Departure from Normal: -2.91)

Annual Precipitation: 30.87 inches

(Departure from Normal: +2.56)

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

SEPTEMBER NORMALS, RECORDS & FACTS

Fall officially arrives at 12:03 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).

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

SEPTEMBER OUTLOOK

Midway through the first week of September, we are off to a cool, wet start. Nearly two inches of rain fell with the remnants of Ernesto (Sept. 1 and 2) and temperatures have averaged 6 degrees below normal through the first five days. The forecast question, then, is whether these trends will continue. I think not.

I see a new pattern of west or northwest flow dominating across our area for at least the next ten days. This means we’ll likely see below normal precipitation with only a few isolated showers with passing fronts. Temperatures will be quite variable as they warm-up ahead of approaching fronts (Sept. 8 and 9), then cool down behind the front (Sept. 10 and 11). Another warm-up and cool-down will likely follow during mid-month as the pattern repeats itself. What I don’t see is any late-summer heat with highs of 90 or above. Instead, I believe temperatures will hold within five degrees of normal—which means a very nice stretch of weather may be on tap for the next couple of weeks.

Of course, September is the peak of hurricane season and we’ll need to keep watch for systems approaching the US that might infuse moisture into our pattern. The current storm, Florence, looks like she will recurve off the east coast and not affect our weather (but stay tuned for possible changes in her path). I would expect a couple more named storms later this month, but there’s no guarantee they would track our way and bring us precipitation. In fact, if northwest flow continues across the Great Lakes and Northeast, this would tend to “protect” us from such storms and led to a relatively dry pattern for much of the month.