Friday, July 24, 2009
Weather columnist Kevin Myatt: July has been playing it cool in many areas
Kevin Myatt is The Roanoke Times' weather columnist.
kevin.myatt
@roanoke.com
981-3341
Weather with Kevin Myatt
Recent columns
- We got graupel, but not on official record
- Moisture could get caught up in cold blast
- Forecast for Weather Journal: Partly print, with frequent Internet
- Column archive
Read the Weather Journal blog
- Sprinkles or flurries possible Tuesday, but maybe something bigger for the weekend?
- For now, it looks like a quiet, mostly mild week ahead for SW Virginia
- Coldest morning of winter so far likely across much of Southwest Virginia; Tuesday precipitation looking doubtful
- Weather Journal blog
#swvawx on Twitter
@KevinMyattWx
International Falls, Minn., is nicknamed the "Icebox of the Nation," but even there, it's not supposed to be in the mid-30s in July.
Midsummer lows in the city on the Canadian border are typically in the lower 50s. But some days this July, the low 50s have been the high temperatures. On July 16, the high of 53 in International Falls was 10 degrees below the coldest high previously reported on the date 53 years ago.
A few 90-degree days are common for New York's Central Park, but there haven't been any there yet in June and July. July has a solid chance to finish as the Big Apple's coolest since the 1880s.
Lincoln, Neb., set a record low on Friday, July 17. Then again on Saturday. And yet again on Sunday.
Madison, Wis., averaged 65.1 degrees through the first 22 days of July. That's more than a degree and a half below the coldest July on record way back in 1891, and the weather pattern in July's final week appears likely to keep Madison in record territory.
It's not just Southwest Virginia that is skipping the heat this summer. It's been a radically cool July across much of the northern and eastern U.S.
Through Wednesday, Roanoke has averaged 72.6 degrees through the first 22 days of the month. Only two other Julys -- 71.7 degrees in 1947 and 71.8 degrees in 1918 -- have averaged cooler through 31 days. July's normal average temperature is 76.2 degrees.
With temperatures expected to be near or below the normal high of 88 and low of 66 each day through the end of next week, it appears that July 2009 is almost a lock, barring unforeseen extreme heat, to finish among the 10 coolest Julys on record dating to 1912.
The cause of the summer chill is the same as the cause of the nation's coldest winters.
High pressure near Greenland has remained firmly anchored much of the summer. This has forced the jet stream behind it, which usually zips west to east rapidly across Canada, to buckle southward deep into the eastern U.S. The southward dip has brought reinforcing shots of unseasonably cool air from Canada, deflecting any advance of hot, dry air from the desert Southwest or hot, humid air from the Gulf of Mexico.
But the rule of thumb in national weather is that when there is record cold in one region, there's record heat somewhere else.
McAllen, Texas, hit 106 on Sunday and Monday, then 107 on Tuesday, each breaking a previous daily record by 3 to 5 degrees. Imperial, Calif., hit 117 on Saturday, clearing the old mark by a degree. Roswell, N.M., Page, Ariz., and San Antonio are among numerous sites in the Southwest that have set new record highs in the past week.
By areal coverage and effect on population centers, more of the nation is experiencing unusually cool weather rather than heat.
So for many Americans, it may not quite be a "Year Without A Summer" like 1816, but certainly it has been a year without much of a summer.
Weather Journal appears on Monday, Wednesday and Friday.
