Sunday, June 26, 2011

6/26/11: Sunday's Weather Report

Issued at 5:01 PM CDT, Sunday, June 26th, 2011

WEATHER HEADLINES:

-Occasional rain/scattered thunderstorms Tonight
-Shower chances linger into Monday
-Dry weather Tuesday and Wednesday
-Near to slightly below average temperatures thru Tuesday
-Warm wave mid to late week, especially away from Lake Superior
-Pattern change after the 4th of July?

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A cold front was moving into extreme Northwest Minnesota late This Afternoon.  A moist airmass was in place out ahead of this front Today with dewpoints from 55 to around 65 degrees, PWS around 1.30" with 850mb td's from +8 to +12 degrees C.  An area of showers and isolated thunderstorms pushed through parts of Northern Minnesota This Morning.  Behind these showers, skies were partly sunny to mostly cloudy in Northern-Eastern Minnesota and partly cloudy to mostly sunny in Northwest Wisconsin.  Highs Today were in the 70s, with 50s in Superior and the Duluth Harbor as the lake breeze became more pronounced once again.  Winds Today were out of the south or east under 20 mph.

Today's Upper Level Analysis:

Southwest 500mb flow covered the Upper Midwest per RUC model analysis.  An upper level trough was digging south/east from Western Canada and the Northern Rockies.  A large upper level ridge was in place over the Southern U.S. with extreme heat from Kansas to Texas and into the Southeast U.S.  Note:  Some locations in Oklahoma and Texas topped out over 110 degrees Today!

Tonight:

Cold front moves east into Northern-Central Minnesota Overnight.  Abundant moisture and some forcing associated with the front and approaching H5 trough will lead to occasional rain and showers across Northern Minnesota and Northwest Wisconsin Tonight.  Some of the rain could be locally heavy and scattered thunderstorms are possible as well with a threat for dangerous lightning strikes.  The overall severe threat is rather low, however, with marginal instability with CAPE generally around 500 j/kg with Lifted Indices of zero to -3 degrees C.  Shear is favorable for severe weather though with 1KM Helicity around 200 m2/s2 and 0-6KM and Effective Bulk Shear of 30-40 knots, but the lack of instabilty will likely keep the majority of thunderstorms below severe levels for Tonight.  Mostly cloudy skies are expected Tonight with lows in the 50s to lower 60s.  Winds will be out of the south, west or east under 15 mph.

Monday and Monday Night:

Cold front will pass through Northeast-Eastern Minnesota Monday Morning and will move through Northwestern Wisconsin by mid-Afternoon Monday.  Areas of rain will be found into early Monday Afternoon in Northwest Wisconsin, Northeast and Eastcentral Minnesota with a few Afternoon/early Evening showers and isolated thunderstorms redeveloping in Northcentral Minnesota underneath the cold upper level trough.  Highs Tomorrow under partly sunny to mostly cloudy skies will be in the 60s and 70s with lows Tomorrow Night in the 40s and 50s with partly to mostly cloudy skies.  Winds on Monday will be out of the south, east or west at up to 20 mph.  Winds Tomorrow Night will be out of the northwest at 10-20 mph.

Note:  Rainfall totals of 0.25-0.50" will be common across Northern Minnesota and Northwest Wisconsin by Monday Afternoon with localized greater amounts ranging from 0.50-2.00".

Extended Forecast:

Dry weather is forecast for Tuesday and Wednesday as high pressure moves through the Upper Midwest.  High temperatures will be in the 70s both days with lows in the 40s and 50s.  A vigorous low will pass well to our northwest during the Thursday-Friday (June 30th-July 1st) time frame, the airmass ahead of this system will be extremely capped so as the cold front moves across the area Thursday or early Friday it should come through generally dry with just a small chance for a shower or thunderstorm.  Widespread 80s are still expected on Thursday and possibly on Friday as well, but a lake breeze should keep the warmth from making it to lakeshore communities on Thursday, winds will swing around to the west on Friday though which will bring the warm air right up to Lake Superior.

The EUROPEAN and GFS computer models are hinting at a pattern change after the 4th of July as an upper level low develops in Hudson Bay Canada, this in turn will cause the upper level winds to back more northwest or northerly which could result in a period of cooler than average temperatures once again for portions of the Upper Midwest.  This is still a long ways out, so things may change between now and then.

5 DAY FORECAST FOR DULUTH/SUPERIOR

.Tonight...  Mostly cloudy.  Occasional rain developing.  Isolated thunderstorms also possible.  Low 50 to 55.  Wind east to southeast at 5 to 15 mph.  Chance of rain 80%.

.Monday...  Occasional rain into early Afternoon.  Mostly cloudy.  A few showers still possible during the Afternoon.  High 62 to 67.  Wind becoming west at 10 to 20 mph.  Chance of rain 80% during the Morning and 20% in the Afternoon.

.Monday Night...  Becoming partly cloudy.  Low 48 to 53.  Wind northwest at 10 to 15 mph.

.Tuesday...  Mostly sunny.  High 70 to 75.

.Tuesday Night...  Mostly clear.  Low 48 to 53.

.Wednesday...  Mostly sunny.  High 72 to 77 but cooler near Lake Superior.

.Wednesday Night...  Partly cloudy.  Low 50 to 55.

.Thursday...  Partly cloudy.  High 73 to 78 but cooler near Lake Superior.

Normal temperatures for Tomorrow

High:  74 degrees
Low:  51 degrees

Monday's Pollen Forecast:

Grass:  High
Tree:    None
Weed:  None

Sunrise Tomorrow:  5:16 AM CDT
Sunset Tomorrow:   9:07 PM CDT

Tim