Saturday, August 7, 2010

8/7/10: Saturday's Weather Report

Issued at 4:05 PM CDT, Saturday, August 7th, 2010

Weather tidbits:

*Today marks the 39th consecutive day with a high temperature of at least 70 degrees in Duluth, Minnesota.

*The all time record which is 46 days in a row with a high temperature of 70 degrees or above occurred from July 20th through September 3rd, 1877!

*2nd place occurred from July 25th through September 5th, 1983 (43 days).

*3rd place occurred from July 9th through August 18th, 1969 (41 days).

At this time it does appear that we will be making a run at the all time record.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A warm front as of 3 PM CDT was sitting over Northcentral Minnesota with a secondary warm front draped over the Southwest portion of Minnesota. Low pressure of 1001-1003 mb was sitting along the Southern North Dakota-Northern South Dakota state line. Moisture and instability has been increasing across our local area Today with the latest meso-analysis indicating CAPE values of 1000-2000 j/kg along and south of U.S. Highway 2. Lifted Indices of -2/-6 degrees C with Lapse Rates around 6.0-7.0 c/km. There was also quite a bit of wind shear in place This Afternoon with 0-6 KM BULK SHEAR and EFFECTIVE BULK SHEAR of 30-40 knots with 1KM SHEAR up to 20 knots. There has been some showers and thunderstorms affecting mainly Southern parts of our area at times Today, but no severe weather has developed yet. Most of the activity Today has been confined to areas from around Brainerd to Lawler down through Willow River and Sandstone, then across the Northwest Wisconsin Counties of Burnett, Washburn and Southwestern Sawyer. The main hazards out of the storms Today has been from heavy rainfall with hourly rates approaching 0.50-0.75" in a few locales, occasional lightning strikes have also occurred. A seperate area of mainly light rain showers has been tracking east through Northern Minnesota This Afternoon with most of this activity staying north of a line from Big Falls to Isabella.

Partly-mostly cloudy skies covered Northern Minnesota and Northwest Wisconsin Today with high temperatures in the lower 70s from Duluth and along the North Shore of Lake Superior with middle 70s to lower 80s elsewhere. Dewpoints This Afternoon were mostly in the 60s with PWS of 1.00-1.70"!

Today's Upper Level Analysis:

Westerly flow aloft covered the Upper Midwest Today per water vapor satellite imagery. A rather potent disturbance was heading east through the Dakotas and the Manitoba Lakes region late Today while a plume of monsoonal moisture continued to stream north through the Southwest U.S. and the Rockes.

Tonight:

A warm front located near Central Minnesota combined with the upper level disturbance moving east out of the Northern Plains will be the focus for scattered showers and thunderstorms across our local area Tonight.

CAPES of 1000-2000 j/kg, Lifted Indices of -2/-8 degrees C and Lapse Rates >6.0 c/km will be in place especially along and south of U.S. Highway 2 Tonight which will lead to the thunderstorm activity.

W/NW winds of 30-40 knots at 500 mb will veer southwest at 850 mb and S/SE near the surface which combined with 30-50 knots of SHEAR and around 20-25 knots of 1KM SHEAR along with 0-1 KM Helicity values around 150-200 m2/s2 could lead to a few rotating supercell thunderstorms This Evening, especially near the warm frontal boundary in Central Minnesota, but this could also include the Counties of Cass, Crow Wing, Aitkin, Pine, Burnett and Washburn within our local area. Large hail and damaging winds will be the main threats from severe weather Tonight, but an isolated tornado risk is also possible This Evening in Central-Eastern Minnesota where VGP values were around 0.2 as of late This Afternoon per meso-analysis.

An 850 mb jet (low level jet) from the SW at 20-35 knots will continue to advect deep moisture and instability northeast into our area Tonight and with all the moisture in place the potential for very heavy rainfall is present with some localized flooding possible during the night especially in areas that see a few rounds of thunderstorms...Right now this potential seems to be targeting southern portions of our area.

Partly-mostly cloudy skies are expected Tonight with lows in the 50s and 60s with winds out of the south or east under 20 mph.

Sunday and Sunday Night:

A lingering surface boundary will be draped around our area Tomorrow and Tomorrow Night, strong winds aloft will also be located over the Upper Midwest. Instability and moisture will also linger with CAPES of 1000-2000 j/kg and Lifted Indices of -2/-5 degrees C. Dewpoints should hold in the 60s with PWS >1.00". Partly-mostly cloudy skies will be found in our area during this period with the possibility for a few showers or thunderstorms at times. An isolated severe weather risk does exist Tomorrow Afternoon/Evening in our area with large hail and damaging winds being the main threats from any severe thunderstorm that develops. Highs Tomorrow will be in the 70s and 80s, but a few locales in western parts of our area could approach 90 degrees depending on the amount of sunshine. Lows Tomorrow Night will be in the 50s and 60s. Winds during this period will be out of the east or west under 20 mph.

Extended Forecast:

A moist and unstable airmass will continue to sit over the Upper Midwest most of next week as a W/SW 500 mb flow remains in place. A couple disturbances/low pressure systems embedded within the 500 mb flow will pass through the Northern Plains and Upper Midwest on occasion bringing with them a chance for showers and thunderstorms and possibly some severe weather and or heavy rainfall. High temperatures Monday and Tuesday will be in the 70s and 80s but a few locales could approach 90 degrees especially on Monday. Lows Monday Night and Tuesday Night will be mainly in the 60s.

5 Day Forecast for Duluth/Superior

.Tonight... Scattered showers or thunderstorms. Variable cloudiness. Patchy fog possible late. Low 58 to 63. Wind east to southeast at 10 to 15 mph. Chance of rain 60%.

.Sunday... Humid. Variable cloudiness. Showers or thunderstorms possible. High 75 to 80. Wind east at 5 to 15 mph. Chance of rain 20%.

.Sunday Night... Showers or thunderstorms possible. Partly cloudy. Low 58 to 63. Wind variable at 5 to 15 mph. Chance of rain 20%.

.Monday... Partly sunny. High 82 to 87.

.Monday Night... Partly to mostly cloudy. Low 60 to 65.

.Tuesday... Showers or thunderstorms possible. Partly sunny. High 78 to 83. Chance of rain 30%.

.Tuesday Night... Showers or thunderstorms possible. Mostly cloudy. Low 62 to 67. Chance of rain 30%.

.Wednesday... Showers or thunderstorms possible. Partly sunny. High 80 to 85. Chance of rain 20%.

Normal High Temperature Today 76 degrees

Normal Low Temperature Today 55 degrees

Tim