Thursday, July 1, 2010

7/1/10: Thursday's Weather Report

Issued at 3:55 PM CDT, Thursday, July 1st, 2010

Weather history:

On this date in 1988... A record low temperature of 35 degrees occurred at Duluth, Minnesota.

...Flash flooding hit portions of far Northern and far Northeast Minnesota early Today...

A small but potent complex of heavy rain and thunderstorms developed early This Morning in far Northern Minnesota. This complex of thunderstorms affected Northern and the Eastern half of Koochiching County through Northern St. Louis County, and through Northern Lake and most of Cook County Minnesota This Morning. Doppler radar rainfall estimates out of Duluth, MN indicate as much as 4.00-6.00" of rain may have fallen over far Northern St. Louis and Northern Koochiching Counties Minnesota with widespread 1.00-3.00" totals common elsewhere. The axis of this heavy rain occurred along a Big Falls and Littlefork line, up through International Falls and Ray, and then along and north of a line from Nett Lake, Orr, and Ely, through Forest Center, Lutsen, and Grand Marais.

Here are some storm reports and rainfall totals out of far Northern Minnesota from earlier Today. Source: NWS Duluth, MN.

Kabetogama MN (St. Louis County) 3.44". Water was over some roads in the area.

International Falls MN (Koochiching County) 3.00". Skywarn Spotters reported roadway flooding going into International Falls along Highway 53, south of town. Approximately 2-3" of water on the road.

Littlefork MN (Koochiching County) 1.15"

Cook MN (St. Louis County) 0.09"

Silver Bay MN (Lake County) 0.04"

3 miles East of Orr MN (St. Louis County) 0.10"

Note: No 80's at International Falls during the month of June 2010, this is only the 4th time in the 80 years of weather records that a June failed to produce any 80 degree days during the month of June at International Falls, Minnesota. The previous years were: 1947, 1982, and 1985. The first day of July arrives Today and the high temperature as of 4 PM CDT was 86 degrees at International Falls!

Weather tidbits for Duluth, MN (Airport location)

*Number of days with a high temperature of at least 70 degrees in 2010 ending on June 30th: 27, last year up until the 30th we had 17 days.

*Number of days with a high temperature of at least 80 degrees in 2010 ending on June 30th: 5, last year up until the 30th we had 7 days.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

The complex of thunderstorms and heavy rainfall which affected a small part of extreme Northern and Northeast Minnesota earlier Today has departed off to the east-northeast This Afternoon leaving behind partly-mostly sunny skies in Northern Minnesota with mainly sunny skies the farther south you go. A warm front as of mid-Afternoon extended from near Big Falls to Floodwood to just east of Moose Lake Minnesota, then down through Northwestern Wisconsin. There really isn't much of a difference in temperature or humidity on either side of this front, except for the usual marine layer which is keeping it cooler and a tad drier Today in Superior and Downtown Duluth and northeast along the North Shore of Lake Superior. High temperatures Today were in the lower to middle 80s with Brainerd MN all the way up to 88 degrees late Today! Cooler 60s and 70s prevailed along the North Shore of Lake Superior down through Duluth/Superior. Dewpoints This Afternoon were running in the 55-65 degree range with PWS of 1.00"-1.40" in Northern Minnesota to 0.80"-0.90" in Southern parts of our local area. Winds were out of the south or east Today at 10-20 mph with some higher gusts.

Today's upper level analysis:

500 mb ridge (588-594 meters) covered the Upper Midwest, Central Plains, and parts of the Northern Plains Today. Note: 500 mb heights have climbed from 569 meters at Minneapolis, MN back on June 28th to 592 meters Today (July 1st)! A similar trend has occurred at International Falls, MN where 500 mb heights went from 565 meters on June 28th to 586 meters Today! This indicates that the upper level ridge and warmth has built north into Minnesota. Northwest flow aloft along with an upper level trough that was over the Upper Midwest in recent days has moved into the Northeast U.S./Eastern Canada Today per water vapor satellite imagery and RUC model analysis. 850 mb temperatures as of 4 PM ranged from +15/+21 degrees C across Northwest Wisconsin and Northern Minnesota while 700 mb temperatures ranged from +10/+12 degrees C from Cass Lake and Grand Rapids to near Duluth through far Northwest Wisconsin and points southwest from there. To our west, an upper level trough was in place over the Northern Rockies and Pacific Northwest with a 500 mb low moving toward Washington state and Oregon late Today per water vapor satellite imagery.

Tonight through Friday Night:

A very warm period ahead as southerly winds continue to advect warm and moist air north into our area as high pressure remains well to our southeast while deep low pressure remains well to our west. A warm front will move through Northern Minnesota This Evening while a cold front currently over the Northern Rockies heads east into the Northern Plains Tomorrow and Tomorrow Night. Temperatures aloft will consist of +15/+22 degree C 850 mb readings while 700 mb temperatures vary between +8/+12 degrees C, in other words the airmass will be quite capped, but a few showers and thunderstorms can't be ruled out at times Tonight and again Friday Night...Mainly in extreme Northern Minnesota. Clear-partly cloudy skies can be expected across our area from Tonight through Tomorrow Night with low temperatures in the 50s and 60s Tonight and the 60s and 70s Tomorrow Night. Highs Tomorrow will be mainly in the 80s, but a few locales could push toward the 90 degree mark! An 850 mb jet out of the southwest will increase to between 30-50 knots at times through Tomorrow Night, and this should lead to some gusty south or southwest winds across our area with wind speeds averaging 15-20 mph, but gusts from 20-35 mph could occur.

Extended Forecast:

Very warm and muggy conditions will linger Saturday and Saturday Night in Northern Minnesota and Northwest Wisconsin as a cold front moves into Western Minnesota. The atmosphere along and slightly ahead of this boundary is forecast to become very unstable Saturday Afternoon/Evening with CAPES of 1500-3000 j/kg and Lifted Indices from -3/-7 degrees C. A layer of warm air aloft should prevent thunderstorms from developing until late Saturday Afternoon or Saturday Evening, but when they do develop they could turn severe thanks to all the instability that is forecast to be in place. At this time it appears that areas along and west-northwest of a line from Crane Lake to McGrath Minnesota will be most susceptible to seeing possible severe weather with damaging winds and large hail being the main threats from any severe weather late Saturday Afternoon or Saturday Evening.

The risk for showers or thunderstorms will overspread all of our area Saturday Night with heavy rain a distinct possibility due to the abundant low level moisture in place with dewpoints from 65-75 degrees, 850 mb td's around +16 degrees C and PWS ranging from 1.75"-2.00"! Areas of flooding could develop Saturday Night-early Sunday in parts of our area, especially if thunderstorms train over the same locations over and over again, which is possible. High temperatures on Saturday will be in the 80s and 90s with lows Saturday Night in the 60s and 70s.

The fourth of July (Sunday/Sunday Night) will see the cold front move slowly south-east during this period with the front expected to be from Central Wisconsin down toward the Iowa-Minnesota border by late Sunday. Showers or thunderstorms could continue along with a heavy rain threat on Sunday, especially in Northwest Wisconsin and Eastern Minnesota while Northern Minnesota should be dry. The focus for showers or thunderstorms will shift slightly more to the south/east come Sunday Night, with locations such as Hayward, Park Falls, and Hurley Wisconsin having the best chance at getting wet while the remainder of our area should be dry for Sunday Night the way it looks now. High temperatures on Sunday will be in the 70s and 80s with humid conditions persisting as well. Lows Sunday Night will be in the 50s and 60s.

Note: The combination of very warm temperatures the next few days along with increasing amounts of humidity may result in heat index values reaching the upper 80s and 90s in some parts of Northern Minnesota and Northwest Wisconsin during the Afternoon and Evening hours. Heat advisories may be issued Friday and or Saturday by the National Weather Service.

5 Day Forecast for Duluth/Superior

.Tonight... Mild and somewhat humid. Mostly clear. Low 58 to 63. Wind south at 10 to 20 mph.

.Friday... Very warm, breezy, and humid. Mostly sunny. High 81 to 86. Wind south at 15 to 25 mph. Afternoon heat indices from 85 to 90 degrees.

.Friday Night... Warm, breezy, and humid. Partly cloudy. Low 65 to 70. Wind south at 15 to 25 mph.

.Saturday... Very warm, breezy, and humid. Partly cloudy. High 85 to 90. South winds could occasionally gust to 25 mph. Afternoon heat indices around 95 degrees.

.Saturday Night... Very warm and muggy. Showers or thunderstorms developing. Heavy rainfall possible. Partly to mostly cloudy. Low 67 to 72. Chance of rain 60%.

.Fourth of July... Muggy. Showers or thunderstorms possible, especially through early Afternoon. Mostly cloudy. High 75 to 80. Chance of rain 60%.

.Sunday Night... Partly to mostly cloudy. Low 57 to 62.

.Monday... Partly sunny. High 78 to 83.

Normal High Temperature Today 74 degrees

Normal Low Temperature Today 52 degrees