Saturday, September 18, 2010

9/18/10: Weather Report

Issued at 4:37 PM CDT, Saturday, September 18th, 2010

...All headlines issued by the National Weather Service Duluth, Minnesota...

*FROST ADVISORY*

Timing:

12 AM CDT Tonight until 6 AM CDT Sunday

Counties included in the advisory:

Southern St. Louis MN...Aitkin MN...Crow Wing MN...Cass MN...Carlton MN...Pine MN...Douglas WI...Bayfield WI...Ashland WI...Iron WI...Burnett WI...Washburn WI...Sawyer WI...and Price WI...

Some cities included in the advisory:

Duluth MN...Floodwood MN...Hill City MN...Aitkin MN...Brainerd MN...Cross Lake MN...Pine Center MN...Leader MN...Longville MN...Cass Lake MN...Cromwell MN...Moose Lake MN...Hinckley MN...Pine City MN...Superior WI...Solon Springs WI...Port Wing WI...Bayfield WI...Cable WI...Ashland WI...Butternut WI...Hurley WI...Mercer WI...Danbury WI...Grantsburg WI...Minong WI...Shell Lake WI...Hayward WI...Exeland WI...Park Falls WI...Phillips WI...and Ogema WI...

Discussion:

Mostly clear skies and light winds will allow temperatures to drop into the middle 30s across the advisory area Tonight. Areas of frost will develop Overnight into early Sunday.

A frost advisory means that frost is possible. Sensitive outdoor plants may be killed if left uncovered.

*FREEZE WARNING*

Timing:

12 AM CDT Tonight until 6 AM CDT Sunday

Counties included in the warning:

Cook MN...Lake MN...Central and Northern St. Louis MN...Itasca MN...and Koochiching MN...

Some cities included in the warning:

Hovland MN...Grand Portage MN...Grand Marais MN...Silver Bay MN...Forest Center MN...Isabella MN...Two Harbors MN...Hibbing MN...Makinen MN...Ely MN...Crane Lake MN...Bigfork MN...Grand Rapids MN...International Falls MN...Littlefork MN...and Northome MN...

Discussion:

Mostly clear skies and light winds will allow temperatures to tumble into the middle 20s to lower 30s in the warning area Tonight. Frost and a killing freeze is expected by Sunday Morning.

A freeze warning means sub-freezing temperatures are imminent or highly likely. These conditions will kill crops and other sensitive vegetation.

Low temperature report for Saturday, September 18th, 2010. Source: NWS Duluth, Minnesota.

Duluth MN: 35 degrees

International Falls MN: 32 degrees

Two Harbors MN: 34 degrees

Silver Bay MN: 34 degrees

Grand Marais MN: 34 degrees

Ely MN: 34 degrees

Orr MN: 34 degrees

Bigfork MN: 32 degrees

Longville MN: 32 degrees

Superior WI: 37 degrees

Littlefork MN: 35 degrees

Cook MN: 32 degrees

Embarrass MN: 31 degrees

Floodwood MN: 34 degrees

Kabetogama MN: 34 degrees

2 miles south of Tower MN: 33 degrees

Weather History:

On this date in 2000 and previous years... A record high temperature of 84 degrees occurred at Duluth, Minnesota.

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

High pressure averaging 1026 mb was centered in Central South Dakota late Today with low pressure covering Hudson Bay Canada. Partly cloudy-sunny skies were found across our area Today with high temperatures in the middle to upper 50s. The airmass is very dry with dewpoints This Afternoon only in the 30s with PWS of just around 0.30"! Winds Today were out of the west or northwest under 20 mph.

Today's Upper Level Analysis:

A large upper level low pressure system covered northern-northeast parts of Canada Today per water vapor satellite imagery with a strong upper level jet >100 knots occurring on the southwest side of this low per RUC model analysis. The 500 mb flow across the Upper Midwest was generally out of the west Today. A new upper level trough/upper low was heading toward the Pacific Northwest Today per water vapor satellite imagery.

Tonight:

High pressure will head into the Upper Midwest, look for clear-partly cloudy skies with west or northwest winds under 15 mph. Lows will be in the 20s and 30s with areas of frost for most areas, along with a killing freeze generally north-northwest of a line from Grand Rapids to Grand Marais Minnesota.

Sunday and Sunday Night:

High pressure will remain over the Upper Midwest during this period, look for partly-mostly cloudy skies with highs Tomorrow in the 50s to lower 60s with lows Tomorrow Night in the 30s and 40s. West or northwest winds under 20 mph are expected on Sunday with winds turning to the east Sunday Night under 15 mph.

Extended Forecast:

High pressure ridge will shift off to our north/east on Monday with low pressure developing across the Western High Plains. This low is expected to deepen a bit with pressures falling to around 997 mb as it heads northeast across the Northern Plains, toward Northern Lake Superior from Monday into Tuesday Morning. A warm front attached to this low will surge north Monday and Monday Night with a cold front heading east through our area Monday Night/Tuesday Morning.

This system will have some moisture to work with as dewpoints climb into the 50s by late Monday while PWS increase to around 1.25" with 850 mb td's of around +10 degrees C by Monday Evening/Overnight. A strong low level jet of 40-55 knots is also expected to develop across the Upper Midwest Monday and Monday Night and this will result in a strong warm advection pattern spreading south to north across Minnesota on Monday. 850 mb temperatures which will start the day around +4/+6 degrees C are forecast to rise to between +12/+20 degrees C by Monday Night! Instability, especially in the form of elevated CAPE is also forecast to surge north/east into our area by Monday Afternoon and Monday Night with CAPES of around 500-1000 j/kg. The issue with this system will be the strong mid level cap as 700 mb temperatures soar to between +8/+12 degrees C early next week which is very warm for this time of year. There should be some showers or thunderstorms in Northern Minnesota and Northwest Wisconsin as this system passes through our local area from Monday into Tuesday Morning, there could even be an isolated severe thunderstorm Monday Evening or Overnight, but this would depend on whether or not the mid levels can cool enough which doesn't look very likely at the moment.

This low pressure system exits to our north/east on Tuesday with some lingering showers mainly in Northwest Wisconsin and far Northeast Minnesota. Dry weather is then expected Tuesday Night through Wednesday with high pressure moving into the Upper Midwest. The next shot for some rain will come late next week (Thursday and or Friday)

High temperatures for Monday and Tuesday will be in the 50s and 60s with lows Monday Night in the 40s and 50s with 30s and 40s expected for Tuesday Night.

5 Day Forecast for Duluth/Superior

*FROST ADVISORY* IN EFFECT FROM 12 AM CDT TONIGHT UNTIL 6 AM CDT SUNDAY.

.Tonight... Partly cloudy. Areas of frost possible late. Low 35 to 40. Wind west to northwest at 5 to 15 mph.

.Sunday... Partly sunny. High 57 to 62. Wind west at 5 to 15 mph.

.Sunday Night... Partly cloudy. Low 40 to 45. Wind becoming east at 10 to 15 mph.

.Monday... Showers possible. Mostly cloudy. High 55 to 60. Chance of rain 30%.

.Monday Night... Showers at times. A few thunderstorms also possible. Mostly cloudy. Low 47 to 52. Chance of rain 50%.

.Tuesday... Showers possible mainly early. Mostly cloudy. High 55 to 60. Chance of rain 40%.

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

.Wednesday... Partly cloudy. High 55 to 60.

Normal High Temperature Today 64 degrees

Normal Low Temperature Today 44 degrees

Tim