Friday, July 30, 2010

7/30/10: Friday's Weather Report

Issued at 4:15 PM CDT, Friday, July 30th, 2010


*3 confirmed tornadoes in Northwest Wisconsin on Tuesday, July 27th, 2010.

*Morse WI tornado (Ashland County) 6:24 PM CDT: Preliminary EF-1 rating with wind speeds of 86-110 mph.

*Eastern Ashland County Wisconsin tornado (7:12 PM CDT) Preliminary EF-0 rating with wind speeds of 65-85 mph.

*Turtle Flambeau Flowage tornado (Iron County) Start time: 7:20 PM CDT, 9.7 miles Southwest of Mercer Wisconsin. End time: 7:26 PM CDT, 6.5 miles Southwest of Mercer Wisconsin. Preliminary EF-1 rating with wind speeds of 86-110 mph. Path length: 4.8 miles. Max width: 3/8 miles or 660 yards.

July 2010, record setting at Duluth, MN. Source: NWS

Every day so far in July 2010 has featured a high temperature of at least 70 degrees at Duluth Minnesota. This is only the 2nd time in Duluth weather history which goes back 137 years for such a feat to occur. The last time this happened was in July of 1988. Even the warmest July on record (2006) featured one day where the high temperature failed to reach 70 degrees, that occurred on July 10th, 2006 when the maximum temperature was just 65 degrees.

Weather History:

On this date in 1995 and in previous years...A record high temperature of 94 degrees occurred at Duluth Minnesota.

On this date in 1992 and previous years...A record low temperature of 42 degrees occurred at Duluth Minnesota.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

Moisture has been increasing across our area Today as southerly winds develop on the back side of an area of high pressure which was centered over the Eastern Great Lakes This Afternoon. Dewpoints late Today were generally in the lower to middle 60s across our local area with PWS of 1.20-1.60". Mostly cloudy skies were found in our area Today with scattered showers affecting parts of our area. High temperatures Today due to the clouds and scattered rain stayed in the 65-75 degree range with south or east winds under 20 mph.

Today's Upper Level Analysis:

Northwest flow aloft covered the Upper Midwest Today per water vapor satellite imagery and RUC model analysis. An upper level ridge was in place across the Central-Southern Rockies through the Central-Southern Plains and the Southeast U.S. A couple of disturbances embedded within the fast W-NW 500 mb flow were dropping southeast through Western-Central Canada down through the Northern Plains/Upper Midwest.


Scattered showers and mostly cloudy skies with areas of fog will be the rule across Northern Minnesota and Northwest Wisconsin Tonight...A warm front sitting near the Eastern Dakotas late Today combined with some disturbances heading southeast into our area will lead to some rain at times Tonight. There is some instability around portions of our area late This Afternoon with meso-analysis showing CAPES of around 500-1000 j/kg with Lifted Indicies of -1/-4 degrees C. This will be enough to support a few thunderstorms with brief heavy downpours and occasional lightning strikes Tonight, but severe weather is not expected. Lows Tonight will be in the 50s and 60s with winds out of the south, west, or east under 15 mph.

Saturday and Saturday Night:

W/NW flow aloft will continue during this period. Some instability will remain in place with CAPES maxing out around 1000 j/kg with Lifted Indices as low as -3 degrees C. Any weak impulse dropping southeast into the Upper Midwest will tap into this instability and will lead to a few showers or thunderstorms in Northern Minnesota and Northwest Wisconsin Tomorrow and Tomorrow Night, otherwise expect partly-mostly cloudy skies during this period with highs Saturday in the 70s and 80s with lows Saturday Night in the 50s and 60s. Winds during this period will be out of the west, south, or east under 15 mph.

Extended Forecast:

An area of low pressure with it's warm front and cold front is forecast to track across the Northern Plains and Upper Midwest from Sunday into Monday. The forecast models Today and over the past few days have differed on how rapidly to spread showers/thunderstorms into our area. The NAM-WRF model has a faster solution compared to most of the other models Today, a faster solution would result in rain chances Sunday through Monday while a slower solution would result in the better rain chances occurring from Sunday Evening/Overnight into Monday. The prospects for severe weather seem to be diminishing a bit compared to 24 hours ago for our local area, but this could still change. A southwest low level jet >30 knots is expected to be in place ahead of this system late this weekend, this along with favorable shear and winds aloft could still result in some severe weather should the instability increase with future model runs.

High temperatures Sunday and Monday will be in the 70s and 80s across our area with low temperatures in the 50s and 60s both nights.

5 Day Forecast for Duluth/Superior

.Tonight... Mostly cloudy with areas of fog. Scattered showers ending Overnight. An isolated thunderstorm also possible. Low 56 to 61. Wind east to southeast at 5 to 15 mph.

.Saturday... Partly sunny. Showers or thunderstorms possible. High 75 to 80. Wind variable at 5 to 15 mph. Chance of rain 20%.

.Saturday Night... Partly to mostly cloudy. Low 57 to 62. Wind variable around 12 mph.

.Sunday... Partly sunny. High 75 to 80.

.Sunday Night... Mostly cloudy. Showers or thunderstorms possible. Low 60 to 65. Chance of rain 30%.

.Monday... Showers or thunderstorms possible. Mostly cloudy. High 75 to 80. Chance of rain 30%.

.Monday Night... Becoming partly cloudy. Low 60 to 65.

.Tuesday... Partly cloudy. High 80 to 85.

Normal High Temperature Today 76 degrees

Normal Low Temperature Today 56 degrees