“Humigeddon 2011” sets records; “Fresh front” brings relief

The record hot, muggy & buggy summer of 2011 is taking a long overdue break. But not before blowing some records for summertime humidity out of the water.

Another muggy day with 70s dew points in Minnesota Tuesday. Some of the highest dew points in the nation have pooled over Minnesota this summer.

The data from Twin Cities NWS & The Minnesota Climate Working Group.

Twin Cities International Airport

Greatest Number of hours with dew point

temperature of 75 degrees F

(1945-2011)

Rank Year Hours

--------------------

1. 2011 98 (as of 3pm August 1)

2. 2001 78

3. 1999 64

4. 1987 60

5. 1995 56

1981-2010 average = 18

That's more than two full "work weeks" of dewpoints at or above 75 in the metro (and much of central & southern Minnesota) this summer. By that measure, this is the "muggiest" summer on record for Minnesota.

We also broke the all time dew point record in the metro (and possible Minnesota) this summer two weeks ago today.

Record Dew Point Temperature in the Twin Cities: July 19, 2011

"The National Weather Service Forecast Office (NWS) in Chanhassen and the DNR State Climatology Office have conferred on last week's extraordinary dew point temperatures in the Twin Cities. It was agreed that the 82 degree F dew point temperature value reported at 3:00 PM and again at 4:00 PM on Tuesday July 19, 2011 at the Twin Cities International Airport will be considered by these offices as the highest dew point temperature ever recorded in the Twin Cities. The old record in the Twin Cities was 81 degrees at 11:00 am on July 30, 1999.

It is known that July 19 dew point temperatures exceeded 82 degrees F at moments between the routine hourly observations. However, in the interest of historical consistency and practicality in establishing future records, only hourly dew point temperature measurements were utilized to determine the new record.

Heat index values on July 19 were extraordinarily high. The 4:00 PM observation may have tied or set an all-time heat index record for the Twin Cities. The air temperature reported at that hour was 95 degrees F and was paired with the 82 degree F dew point temperature. In the next few weeks, the heat index formula used by the NWS hourly "Weather Roundup" product will be used with the historical hourly air temperature/dew point temperature data set to create a heat index climatology. Another announcement will be sent when this is completed."

Any way you slice it, this has been one of, if not the muggiest summers in Minnesota history.

Relief! Cool front sweeps away storms & "Humigeddon"

A Canadian cool front is sweeping cooler and much drier (more comfortable) air into Minnesota. Dew points are plummeting form the tropically stuffy 70s into the 50s. The air will go from feeling like July in the jungle to October in some parts of Minnesota by Wednesday morning.

The difference in air masses is remarkable, and we'll all be breathing easier as the comfortable air mass slides south by Wednesday morning.

The graphic below illustrates the change in air masses. Wind direction is indicated by the yellow arrows, and potted over surface dew points, the yellow dashed lines. The northwest winds are pumping in much drier "low dew point" air in the 50s into Minnesota late Tuesday, even as tropical dew point sin the 70s hang on in southeast Minnesota.

Tuesday morning storm damage north of the metro:

Another round of storms packed a punch this morning, and some considerable wind damage occurred. Damage reports like this one were common from the north metro to Duluth.

PRELIMINARY LOCAL STORM REPORT

NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN

926 AM CDT TUE AUG 02 2011

..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...

..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....

..REMARKS..

0825 AM TSTM WND DMG ELK RIVER 45.33N 93.57W

08/02/2011 SHERBURNE MN TRAINED SPOTTER

MULTIPLE TREES DOWN...POWER LINES DOWN...TREES ON POWER

LINES.

0847 AM TSTM WND DMG ISANTI 45.49N 93.25W

08/02/2011 ISANTI MN TRAINED SPOTTER

MULTIPLE TREES AND BRANCHES DOWN.

Enjoy the respite from storms Wednesday, low humidity and temps in the 80s the rest of this week!

PH