Monday, September 6, 2010

9/6/10: Monday's Weather Report

Issued at 4:07 PM CDT, Monday, September 6th, 2010

Low temperature report from Today, Monday, September 6th, 2010. Source: NWS Duluth, Minnesota.

International Falls MN: 36 degrees

Hibbing MN: 38 degrees

Grand Marais MN: 34 degrees

Ely MN: 34 degrees

Orr MN: 34 degrees

Bruno MN: 38 degrees

Littlefork MN: 38 degrees

Northome MN: 36 degrees

Embarrass MN: 27 degrees

Floodwood MN: 35 degrees

Kabetogama MN: 32 degrees

3 miles East of Orr MN: 30 degrees

2 miles South of Tower MN: 34 degrees

Weather tidbits:

*Today marks the 5th consecutive day with a below normal maximum temperature at Duluth, Minnesota.

*Average monthly temperature through the 5th of September, 2010 at Duluth, MN: 55.6 degrees/3.4 degrees Below Normal.

Weather History:

On this date in 1986... A record low temperature of 33 degrees occurred at Duluth, Minnesota.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A powerful storm with Autumn like characteristics (minus any snow) continued to develop Today with dual low pressure centers (998 mb) as of 3 PM located in Northeast South Dakota and in Northwest Iowa. Strong pressure falls 2-3 mb/2 hours were occurring late Today across Eastern Minnesota while even stronger pressure rises 2-5 mb/2 hours were found across much of Central-Eastern Nebraska and Southern South Dakota This Afternoon. An impressive temperature gradient was occurring Today with 60s around our local area with 80s to near 90 degree warmth in Iowa and across the Central Plains. Dewpoints late Today were in the 60s from Southcentral Minnesota to Iowa with 30s and 40s hanging tough around Northeast Minnesota. PWS late Today were tightly packed, ranging from 0.50-0.70" from the Iron Range on north with 0.90-1.30" PWS from the Twin Ports, on to the west and south. Mostly sunny skies earlier in the day gave way to increasing cloudiness from southwest to northeast during the Afternoon with some rain showers starting to develop now in Western-Southern parts of our area as this storm takes aim at the Upper Midwest. Winds Today were out of the east at 10-20 mph with gusts of 20-30 mph in some areas. Note: Sky Harbor Airport, Duluth MN reported a wind gust from the NE at 37 mph around 2 PM Today.

Today's Upper Level Analysis:

A potent and negatively tilted upper level trough continues to deepen late Today as it heads east-northeast across the Northern Plains per water vapor satellite imagery. RUC model analysis shows a 70 knot mid level jet surging northeast from Central Nebraska with a 100 knot upper level jet covering parts of Western-Central Nebraska late Today.


Low pressure is forecast to move into Westcentral Minnesota This Evening, then into Central Minnesota Overnight. The low will deepen to around 991-993 mb during the night. Strong forcing tied with the approaching low and also with the intense upper level low/upper trough coming out of the Northern Plains will lead to widespread rainfall across Northern Minnesota and Northwest Wisconsin Tonight with periods of moderate to heavy rain likely as moisture increases This Evening with PWS of 1.00-1.50" with 850 mb td's of +8/+12 degrees C. Scattered thunderstorms are also possible Tonight, especially along and south of a line from Cass Lake to Two Harbors, including all of Northwest Wisconsin. Instability will be limited this far north with CAPES generally under 500 j/kg with Lifted Indices of +1/-3 degrees C, but this combined with how intense this system is should be enough to generate some embedded thunderstorms This Evening and Overnight in Eastcentral Minnesota and Northwest Wisconsin. The overall severe threat is minimal around our area, but isolated strong storms nearing severe levels with a hail and high wind threat does exist before Midnight along and south of a line from Leader to Moose Lake Minnesota, east through most of Northwestern Wisconsin.

By late Tonight, the axis of steadier rainfall should push west-north a bit as the surface low moves into Central Minnesota with a dry slot blasting N/E out of Southern Minnesota. Northwest Wisconsin and parts of Eastern Minnesota will see a more scattered type shower event by late Tonight as the dry slot nears.

A general one half to one inch of rainfall is forecast over our local area Tonight with heavier totals possible, especially near thunderstorms and also in the deformation zone where the rain will persist through the night. Note: Flash flood guidance numbers are running between 2-3" per 1 hour in Eastern Minnesota Tonight and around 3" per 3 hours in these same areas. The HPC has outlined parts of Eastern Minnesota, including Duluth in a *Slight Risk* (5-10%) chance for rainfall amounts to exceed flash flood guidance for Tonight.

Low temperatures Tonight will be in the 40s and 50s with winds out of the east, south or west at 10-20 mph with gusts from 20-40 mph. The strongest wind gusts should occur near Lake Superior.

Tuesday and Tuesday Night:

Low pressure averaging 992 mb is forecast to be near Duluth Minnesota around dawn Tuesday before it shifts E-NE through Northwest Wisconsin and Central/Eastern Lake Superior for Tuesday Afternoon. Areas of rain and some drizzle will persist into mid-Afternoon Tuesday across Northern Minnesota and Northwest Wisconsin, then dry conditions will return from west to east by Tuesday Afternoon into Tuesday Night. Temperatures Tomorrow will be unseasonably cool for early September with highs generally in the 40s and 50s along with mostly cloudy skies and brisk west or north winds at 10-25 mph with gusts of 30-40 mph! Lows Tuesday Night will be in the 30s and 40s with scattered frost possible late, especially away from Lake Superior. Skies will become clear-partly cloudy Tuesday Night with winds out of the north or west around 20 mph or less.

Extended Forecast:

High pressure will remain in control of our weather for Wednesday and Wednesday Night with continued cool temperatures. Highs Wednesday will be in the 50s and 60s with lows Wednesday Night in the 30s and 40s with another threat for scattered frost mainly away from Lake Superior. Changes take place from Thursday through Saturday as a new 500 mb trough develops to our west while a southwest flow aloft kicks in across the Upper Midwest. Chances for showers or thunderstorms will return to our area late this week, possibly lingering into Saturday.

The forecast models Today are showing some timing differences with this late week system, the latest EUROPEAN and GEM-GLOBAL models are the slowest and bring the bulk of the measurable rain to our local area sometime Friday Night or else on Saturday. The GFS is quicker and has been quicker the past few days, this model would bring the bulk of the rain into our area from Thursday through early Saturday.

High temperatures for Thursday will be in the 50s and 60s with lows Thursday Night in the 40s and 50s.

5 Day Forecast for Duluth/Superior

.Tonight... Windy. Rain developing. Isolated thunderstorms also possible. Low 47 to 52. Wind east at 15 to 30 mph with occasional gusts up to 40 mph.

.Tuesday... Windy and cool. Occasional rain ending by early or mid-Afternoon. Mostly cloudy. High 53 to 58. Wind west to northwest at 15 to 30 mph.

.Tuesday Night... Becoming mostly clear. Patchy frost possible late mainly away from Lake Superior. Low 38 to 43. Wind northwest at 10 to 20 mph.

.Wednesday... Mostly sunny. High 58 to 63.

.Wednesday Night... Partly cloudy. Low 38 to 43.

.Thursday... Partly sunny. Showers possible. High 58 to 63. Chance of rain 20%.

.Thursday Night... Partly to mostly cloudy. Showers possible. Low 47 to 52. Chance of rain 20%.

.Friday... Partly sunny. Showers possible. High 57 to 62. Chance of rain 20%.

Normal High Temperature Today 68 degrees

Normal Low Temperature Today 48 degrees