Tuesday, August 10, 2010

8/10/10: Tuesday's Weather Report

Issued at 4:02 PM CDT, Tuesday, August 10th, 2010

Here are some high temperature that were reported in Northern Minnesota and Northwest Wisconsin on Monday, August 9th, 2010. Source: NWS Duluth, MN.

Duluth MN: 89 degrees (3 degrees shy of the record high for the 9th of August)

International Falls MN: 89 degrees

Brainerd MN: 90 degrees

Silver Bay MN: 93 degrees

Crane Lake MN: 90 degrees

Bigfork MN: 90 degrees

Longville MN: 90 degrees

Aitkin MN: 90 degrees

Cloquet MN: 90 degrees

McGregor MN: 90 degrees

Superior WI: 91 degrees

Hayward WI: 90 degrees

Phillips WI: 90 degrees

Northome MN: 89 degrees

Madeline Island WI: 89 degrees

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

Another muggy day, but it was slightly cooler (more so near Lake Superior) compared to Monday thanks to increasing cloudiness throughout the day. A warm front was draped southwest and south of Minnesota Today while an upper level disturbance approaches the Upper Midwest from the Northern Plains. S-SE low level jet of 25-35 knots has resulted in a warm/moist advection pattern Today across Minnesota and this has caused areas of rain/thunderstorms over all but Northeast Minnesota and Northwest Wisconsin. The rain that has fallen so far This Afternoon in Western-Southwest parts of our local area has been rather light with the stronger thunderstorms and heavy downpours remaining over Western, Central and Southern Minnesota Today. High temperatures Today were generally in the 80s, but 70s were common near Lake Superior, dewpoints Today were in the 60s and lower 70s with late day PWS of 1.30-1.60"! Winds Today were out of the south or east at 10-20 mph.

Today's Upper Level Analysis:

Water vapor satellite imagery and RUC model analysis indicates that a SW flow aloft was in place over the Upper Midwest Today with an upper level low shifting north-northeast through Southeastern Saskatchewan Province while a shortwave trough heads northeast out of the Dakotas. An upper level trough covered the Pacific Northwest/British Columbia and the Northeast part of the Pacific Ocean late Today with an upper level low (5700 meters) centered in Central Washington.

Tonight:

A warm front which was over Central Iowa This Afternoon will lift north, reaching Southern Minnesota Tonight while an upper level disturbance and weak cold front head east out of the Northern Plains. A warm and moist airmass will be found out ahead of this system Tonight as a S-SE low level jet around 30 knots continues to pump deep moisture north into our area. The result from this will be for areas of rain/rain showers throughout the night in Northern Minnesota and Northwestern Wisconsin. With dewpoints holding in the 60s to lower 70s, PWS from 1.50-2.00" and 850 mb td's >13 degrees C...A threat for locally heavy rainfall will exist which may lead to some areas of flooding, especially if the heavier showers train over the same locations for a few hours.

Scattered thunderstorms are also expected in our area Tonight, but instability will be limited as CAPES stay <1000 j/kg with Lifted Indices generally from -1/-4 degrees C, but this will be enough to cause some convection at times Tonight. The threat for severe thunderstorms is relatively low Tonight with the marginal instability in place combined with rather weak amounts of wind shear, generally around 30 knots. Winds will be changing direction with height, however, as E-SE winds near the surface veer S-SE at 850 mb and SW at 500 mb, this combined with 1KM Shear values around 25 knots could lead to isolated supercells especially in Central-Eastern Minnesota/Western Wisconsin This Evening. If any severe weather does develop, the main threats would be from damaging wind and large hail, but an isolated tornado is also possible This Evening. In our local area, the severe risk is generally west and south of a line from International Falls to Hinckley to Spooner.

Mostly cloudy skies with areas of fog can be expected Tonight with lows in the 60s to around 70 degrees. Winds will be out of the south or east under 20 mph.

Wednesday and Wednesday Night:

An upper level disturbance along with a weak cold front will move slowly east across our local area on Wednesday. Scattered showers or thunderstorms are possible Tomorrow as this system moves through. Locally heavy rainfall is possible Tomorrow with all the moisture in place, there is also an isolated risk for severe weather Wednesday Afternoon. The forecast models Today show more instability around our area Tomorrow compared to Today, CAPES for Wednesday Afternoon are forecast to range from 1000-2500 j/kg with Lifted Indices around -4 degrees C, but this will be dependent on the amount of clearing that can take place after Tonight's activity. If it stays rather cloudy, then the instability will be much lower. Also, the timing on when the weak cold front moves through is handled differently with the models Today, the NAM-WRF is slower compared to the GFS...If the GFS model is right, then most of Tomorrow would be dry except in far Northeast Minnesota and Northwest Wisconsin. Partly-mostly cloudy skies are expected Tomorrow and Tomorrow Night with highs in the 70s and 80s with lows generally in the 60s. The threat for showers/thunderstorms will end around our area by Tomorrow Evening with mainly dry conditions expected for Tomorrow Night the way it looks now.

Extended Forecast:

Another area of low pressure with a stronger cold front is forecast to pass through the Northern Plains and Upper Midwest from Thursday into early Saturday. Another round of scattered showers and thunderstorms can be expected in our area beginning Thursday Evening or Overnight and lasting at times into early Saturday. A few severe thunderstorms are possible Thursday Night into Friday Evening the way it looks now. High temperatures will be in the 70s and 80s Thursday and Friday with muggy conditions persisting. Lows will be in the 60s both nights. A pattern change is still expected this weekend into early next week as deep low pressure passes east through Central Canada while a northwest flow aloft develops across the Upper Midwest. Cooler and less humid conditions will spread into Minnesota this weekend along with gusty northwest winds.

5 Day Forecast for Duluth/Superior

.Tonight... Humid. Mostly cloudy with occasional showers. Locally heavy rainfall is possible along with a few thunderstorms. Areas of fog. Low 63 to 68. Wind east to southeast at 10 to 20 mph. Chance of rain 70%.

.Wednesday... Humid. Variable cloudiness. Showers or thunderstorms possible. Areas of fog, mainly early. High 80 to 85. Wind becoming southwest at 5 to 15 mph. Chance of rain 30%.

.Wednesday Night... Partly cloudy. Low 60 to 65. Wind variable at 5 to 15 mph.

.Thursday... Partly sunny. High 80 to 85.

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

.Friday... Showers or thunderstorms possible. Variable cloudiness. High 76 to 81. Chance of rain 30%.

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

.Saturday... Showers possible. Variable cloudiness. High 70 to 75. Chance of rain 30%.

Normal High Temperature Today 75 degrees

Normal Low Temperature Today 55 degrees

Tim