MUWIC Newsletter - June 2006

(Issued: June 2, 2006)

Millersville University Weather Information Center (MUWIC)

Eric J. Horst, Director

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

LEAD STORY: Mini-Drought Continues

The ongoing “mini-drought” has not grown worse nor has it abated over the past month. While May rainfall was just over one-inch below normal, a soaking mid-month rain and two weeks of unusually cool temperatures did stave off an escalation of the drought conditions. Stream flows and well depths remain below normal and in the statistical range typical of drought-watch conditions. Soil moisture was replenished with the mid-month soaking, however the heat of late May did result in significant drying.

Short-term improvement is likely as a slow-moving storm crosses the region on June 2nd and 3rd. Still, I do not expect that we’ll see the drought watch lifted anytime soon. Evaporation rates during the summer months require one inch of rain per week to maintain the status quo. Therefore, we’d need rainfall of six inches on more to erase the drought watch by the end of June.

2006 Rainfall by Month (departure form normal)

January - 3.66 (+0.65)

February - 2.30 (-0.17)

March - 0.65 (-2.73)

April – 4.36 (+0.89)

May – 2.33 (-1.29)

TOTAL: 13.30 (-2.65)

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

EVENT OF THE MONTH

Summer unofficially arrived with the occurrence of our first 90-degree day on Memorial Day. The official high temperature on Monday, May 29^th was 91 degrees.

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

STAT OF THE MONTH

A twelve-day cool spell (June 14 – 25) resulted in a remarkable streak of below normal conditions. Temperatures averaged 5.5 degrees below normal throughout this period.

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

MAY CLIMATOLOGY (MU Weather Station)

Average High Temp: 73.1 F

Average Low Temp: 50.8 F

Average Monthly Temp: 62.0 F

(Departure from Normal: 0 F)

Precipitation: 2.33 inches

(Departure from Normal: -1.29)

Annual Precipitation: 13.30 inches

(Departure from Normal: -2.65)

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

JUNE NORMALS, RECORDS & FACTS

Normal high/low temperatures range from 80/54 on June 1st to 85/61 by month’s end. The record high for June is 103 degrees set on the 20th of 1923 and 29th of 1934. The lowest temperature recorded in June is 33 F set on the 5th of 1921 and the 8th of 1932. Normal liquid precipitation for the month is 3.88 inches. The rainiest June on record (14.14 inches) occurred in 1972 when the remains of Hurricane Agnes moved through the region. The driest June was in 1966 when only 0.54 inches fell. Summer officially begins on June 21^st at 8:26 a.m.

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

JUNE OUTLOOK

June began with a high temperature of 90 degrees (June 1), however I do not foresee any more 90-degree days over the next ten to fourteen days. The emerging pattern across the country features a ridge position anchored near NM/TX with a tendency for recurrent troughiness across the Great Lakes and Northeast with a mean trough axis near the eastern seaboard. Therefore, temperatures during the first half of June should average near to slightly below normal. Also, frequent cold fronts will offer occasional chances for showers and perhaps a severe weather event across PA. Given the cellular nature of summertime shower activity there will be some places that receive above-normal rainfall – and major drought relief – while other locations receive only near-normal rainfall. Still, all parts of the Commonwealth should see some improvement in the droughty conditions through the first half of June.

What the second half of the month has in store for us is more difficult to pin down. My gut feeling is that the core of the extreme heat will remain in the place over the Plains while the Northeast will continue near average. There will likely be several opportunities for the heat from the Plains to expand into the Northeast ahead of jet stream disturbances tracking over and downstream of the mean ridge position. Such a set-up could produce a couple two- or three-day spells of 90-degree conditions. In the end, however, it’s my sense that June 2006 will not go down as being extremely warm (in PA). Furthermore, I suspect that near- to above-normal precipitation will prevent the drought conditions for worsening.