Wednesday, May 19, 2010

5/19/10: Wednesday's Weather Report

Issued at 3:20 PM CDT, Wednesday, May 19th, 2010

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

Another gorgeous Spring day across our local area Today with plenty of sunshine with only the far Northeast part of Minnesota and Northwest Wisconsin seeing any sort of cumulus development This Afternoon. Highs Today were in the middle 70s to lower 80s with only slightly cooler temperatures by 3-5 degrees right next to Lake Superior. 850 mb temperatures as of 3 PM were in the +13/+14 degree C range. Surface map as of mid-Afternoon featured high pressure of 1016 mb centered in Eastern Minnesota/Western Wisconsin.

Today's 500 mb analysis:

Upper level low (564 meters) covered the Northeast U.S. Upper level low (570 meters) covered a broad area from Central Rockies east to the Western High Plains/Central Plains region per RUC model analysis. Upper level ridge persisted across the Northern Plains/Upper Midwest Today per RUC model analysis while a rather vigorous system approaches the Pacific Northwest per water vapor satellite imagery.

Tonight through Thursday Night:

Weather pattern will remain unchanged across our area during this period as an area of high pressure remains near our local area. Mostly clear skies are forecast Tonight with lows in the 40s, but some 30s are likely in the typical cold spots. Highs Tomorrow under partly cloudy-sunny skies will top out in the 70s to lower 80s with cooler temperatures at times closer to Lake Superior. Partly-mostly cloudy skies are expected Tomorrow Night with lows in the 40s to lower 50s. Winds will be variable under 15 mph Tonight and Tomorrow with south or east winds Tomorrow Night under 15 mph.

Extended Forecast:

An upper level disturbance will be passing south/southeast of our local area from Friday into Saturday. It still appears that the best coverage of rain shower activity associated with this system will remain to our south, but a few rain showers could develop Friday Afternoon and linger into early Saturday...Mainly in Northwest Wisconsin and Eastcentral Minnesota, if any rain does develop during that period it looks to remain light with only trace to a few hundreths inch of precipitation amounts expected at this time. With more clouds around on Friday compared to recent days high temperatures will be slightly cooler for most areas with mainly 60s and 70s but it will be cooler near Lake Superior. Lows Friday Night will be in the 40s and 50s. High temperatures on Saturday will be in the 60s and 70s with cooler temps near Lake Superior. Lows Saturday Night will be mainly in the 50s.

An upper level trough will become established to our west from this weekend through most of next week per latest model guidance. A couple of low pressure disturbances will likely eject northeast out of the Western U.S. trough and pass west/northwest of the Upper Midwest from this weekend through next week, meanwhile a cold front should stay to our west into early next week before possibly pushing south/east across our area around Tuesday of next week, then this cold front could lift back north as a warm front around the middle of next week.

Two notable changes will take place as southerly winds develop to the east of this trough. One change will be an increase in low level moisture with dewpoints climbing into the 50s and 60s across our area by Sunday with off an on bouts of mugginess likely to persist into next week. The other change will come in the form of higher amounts of instability which could lead to some thunderstorm/severe weather events for portions of the Northern Plains and Upper Midwest depending on the timing of individual disturbances as well as the exact path those systems will take. One thing that could hinder convection from developing around our area will be the development of a strong cap as 850 mb temperatures soar into the +15/+20 degree C range while 700 mb temperatures climb toward +12 degrees C this weekend and early next week. The fuel will be in place, but will we have a trigger to break through the cap? Stay tuned...

5 Day Forecast for Duluth/Superior

.Tonight... Mostly clear. Low 40 to 45. Wind variable under 12 mph.

.Thursday... Mostly sunny. High 75 to 80 but cooler at times closer to Lake Superior. Wind south at 5 to 15 mph.

.Thursday Night... Partly cloudy. Low 45 to 50. Wind east to southeast at 5 to 15 mph.

.Friday... Mostly cloudy. High 65 to 70 but cooler near Lake Superior.

.Friday Night... Mostly cloudy. Low 45 to 50.

.Saturday... Partly sunny. High 68 to 73 but cooler near Lake Superior.

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

.Sunday... Partly cloudy. Showers or thunderstorms possible. Humid. High 75 to 80. Chance of rain 20%.

Normal High Temperature Today 65 degrees

Normal Low Temperature Today 41 degrees

Tim