Wednesday, September 29, 2010

9/29/10: Wednesday's Weather Report

Issued at 4:26 PM CDT, Wednesday, September 29th, 2010

Note:  Arctic air is building over portions of Alaska...Here are some low temperatures from Monday Night/Tuesday Morning in Northern Alaska.  A brief cool snap is forecasted to move into the Upper Midwest this weekend, with perhaps a stronger cold air surge sometime around the middle part of October, although without any snow cover just yet, we won't be dealing with any subzero cold just yet.

Eielson AFB:  3 degrees
Fort Yukon:  0 degrees
Bettles:  0 degrees
Circle Hot Springs:  -5 degrees
Near Delta:  -3 degrees
Chicken:  -5 degrees

Weather History:

On this date in 1984...  A record low temperature of 25 degrees occurred at Duluth, Minnesota.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

Low pressure of 996 mb was centered in Northern Ontario Province as of 4 PM with a cold front attached to this low continuing on it's eastward track through Central Wisconsin late Today.  This system brought a period of clouds and showers along with an a spotty thunderstorm or two across our area This Morning into early This Afternoon...Then skies cleared out briefly, before the upper level trough with it's cold air aloft approached the Upper Midwest This Afternoon.  500 mb temperatures around -17 degrees C combined with LAPSE RATES of 6.0-8.0 c/km with CAPES <500 j/kg and Lifted Indicies from +1/-2 degrees C caused isolated showers and thunderstorms This Afternoon over Northeast Minnesota and far Northwest Wisconsin.  High temperatures Today warmed nicely for late September with 60s and lower 70s common Today while winds were out of the west or northwest at 10-20 mph with some higher gusts.

Today's Upper Level Analysis:

Northwest flow aloft prevailed across the Upper Midwest Today per water vapor satellite imagery with an upper level trough pushing south/east through Central Canada/Minnesota/and the Northern Great Lakes.

Tonight:

Isolated showers or thunderstorms will end before 9 PM with partly to mostly cloudy skies continuing thereafter.  Brief heavy downpours, small hail up to 0.25" in diameter, occasional lightning strikes and wind gusts to 35 mph are possible in the strongest storms before 7 PM.  Lows Tonight will mainly be in the 40s, but a few 30s are possible in the typical cold spots.  Winds Tonight will be out of the west or north at 10-20 mph.

Thursday and Thursday Night:

High pressure will be centered across the Northern Plains through this period which will result in dry conditions for Northern Minnesota and Northwest Wisconsin.  Partly to mostly cloudy skies for Thursday will become partly cloudy Thursday Night.  Highs Tomorrow will be in the 50s and 60s with lows Tomorrow Night in the 30s and 40s.  North or west winds under 20 mph are forecast during this period.

Extended Forecast:

Northerly flow aloft will develop on Friday and will continue most of the weekend with strong high pressure >1032 mb building south/southeast from Central Manitoba Province.  An upper level disturbance moving southeast through our area could trigger a few showers on Friday in Northern Minnesota and Northwest Wisconsin with mainly dry conditions then expected from Friday Night into early next week, although with the colder airmass coming into the area and moving over the warmer waters of Lake Superior, some lake effect rain showers could develop during the Friday Night-Saturday time period for areas along the South Shore of Lake Superior, including Bayfield, Ashland and Iron Counties.  High temperatures will be in the 40s to near 50 degrees in Northern Minnesota with 50s for the rest of our area on Friday with highs Saturday in the 40s and 50s.  Low temperatures will be in the 20s and 30s both nights.

5 Day Forecast for Duluth/Superior

.Tonight...  Isolated showers before 8 PM.  Partly to mostly cloudy.  Low 42 to 47.  Wind west to northwest at 10 to 20 mph.

.Thursday...  Partly sunny.  High 60 to 65.  Wind west to northwest at 10 to 20 mph.

.Thursday Night...  Mostly clear.  Low 40 to 45.  Wind west to northwest at 5 to 15 mph.

.Friday...  Mostly cloudy.  Showers possible.  High 50 to 55.  Chance of rain 20%.

.Friday Night...  Mostly cloudy.  Low 35 to 40.

.Saturday...  Variable cloudiness.  High 48 to 53.

.Saturday Night...  Partly cloudy.  Low 27 to 32.

.Sunday...  Mostly sunny.  High 50 to 55.

Normal High Temperature Today 60 degrees
Normal Low Temperature Today 40 degrees

Tim