Thursday, June 2, 2011

6/2/11: Thursday's Weather Report

Issued at 4:15 PM CDT, Thursday, June 2nd, 2011

Low temperature report for Thursday, June 2nd, 2011.  Source:  NWS Duluth, MN.

Hibbing, MN:  31 degrees
Silver Bay, MN:  30 degrees
Grand Marais, MN:  30 degrees
Ely, MN:  30 degrees
Crane Lake, MN:  28 degrees
Embarrass, MN:  26 degrees
3 miles east of Orr, MN:  31 degrees
2 miles south of Tower, MN:  32 degrees

WEATHER HEADLINES:

-Scattered showers and thunderstorms into Friday Evening
-A few severe thunderstorms possible late Tonight thru Friday Evening
-Isolated tornado risk may develop Friday Afternoon/Evening
-A few showers this weekend?

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

A warm front extended from Southwest North Dakota to Central South Dakota to Eastern Nebraska at mid-Afternoon with low pressure of 996mb centered near Williston North Dakota (NW part of the state) Southerly low level jet has increased to 30-40 knots during the Afternoon out ahead of this system and this is pulling deeper moisture N/NE into our area.  Latest meso-analysis shows PWS of 1.00-1.25" in Northern and Central Minnesota into far Northwest Wisconsin while drier air was hanging on in Northeast Minnesota where PWS were under 1/2".  On the nose of this deeper moisture and just ahead of an instability axis, an area of scattered showers and a few thunderstorms were developing and tracking E-NE through the Iron Range into Northern Minnesota.  Some brief heavy downpours and occasional lightning strikes are the main threats with this activity.  High temperatures Today ranged from the upper 40s to middle 50s near Lake Superior with a few 70s from the Brainerd Lakes, east to Hayward Lakes region with 60s elsewhere.  Dewpoints This Afternoon were in the 40s and 50s away from Lake Superior.

Today's Upper Level Analysis:

500mb low was over Western Montana late Today per water vapor satellite imagery with an upper level trough in place over the Western U.S.  An upper level ridge covered the Central-Southern U.S. Today with widespread 90+ degree temperatures and +20 to +32 degree C 850mb temperatures from parts of the Northern Plains through the Rockies, Central and Southern U.S.  A cluster of strong to severe thunderstorms formed earlier Today in North Dakota, this complex was hitting portions of Manitoba Province This Afternoon to the N-NE of this hot/capped air.

Tonight:

Low pressure will track northeast out of Western Dakota with a warm front lifting NE toward Central Minnesota.  Moisture will continue to increase in our area Today thanks to a persistent 30-45 knot southerly 850mb jet.  Dewpoints will remain in the 40s and 50s away from Lake Superior with PWS of 1.00-1.50" with 850mb td's of +8 to +14 degrees C.  Elevated instability will also increase during the night with MU CAPE of 1000-2000 j/kg.  Scattered showers and thunderstorms will occur at times Tonight in Northern Minnesota and Northwest Wisconsin.  Isolated risk for severe thunderstorms does exist Tonight, mainly for Northcentral and Eastcentral Minnesota with large hail the main hazard from any severe storm.  Locally heavy rain and dangerous lightning will also occur with any thunderstorm that forms Tonight.  Partly to mostly cloudy skies are expected with lows in the 40s and 50s.  Winds will be out of the east or southeast at 5-15 mph with higher gusts.

Friday and Friday Evening:

Main area of low pressure will pass off well to our northwest, but a secondary low will track E-NE across the Upper Midwest.  A warm front will lift slowly N-NE into Eastern Minnesota and Northcentral Wisconsin while a cold front tracks east and through the area from Friday Afternoon into Friday Evening.

700mb temperatures are forecast to climb to around +10 to +12 degrees C on Friday with 850mb temperatures nearing +20 degrees C.  This layer of warm air aloft could decrease the threat for surface based thunderstorms for our area during this period, but the models are showing weakening amounts of CINH during the Afternoon with cooling temperatures aloft, if this occurs...then there will be a greater risk for severe thunderstorms for portions of our area.

There should be plenty of instability in place for a thunderstorm to tap into with CAPES ranging from 1000-2500 j/kg while Lifted Indicies decrease to -2 to -7 degrees C.

Mid level winds from the SW at 40-60 knots will cover our area with a speed max >75 knots ejecting E-NE out of the Northern Plains.  Upper level winds will range from 90-110 knots in the Northern Plains to around 75 knots in Northern Minnesota and Northwest Wisconsin.

0-6KM and EFFECTIVE BULK SHEAR will be sufficient for severe storms with values around 40-50 knots while 0-1 and 0-3 KM HELICITY range from 100-250 m2/s2. 

If surface based thunderstorms can develop Friday Afternoon or Friday Evening, there will then be a risk of severe thunderstorms with large hail and damaging winds being the main threats...But, a few tornadoes could also develop between 2PM-6PM, mainly in Northwest Wisconsin.  Should the cap win out, there would still be a risk for storms, but these storms would stay mostly elevated with mainly a large hail threat.

High temperatures on Friday will be in the 70s and 80s with dewpoints rising into the 60s for most areas.  It will be cooler near Lake Superior with highs in the 50s.  Winds on Friday will be out of the south, east, or west at 10-20 mph.

Overnight Friday:

Cold front will exit to our east with dry weather returning to the area.  Partly cloudy skies are forecast with lows in the 40s and 50s.  Winds will be out of the west or southwest at 10-20 mph.

Extended Forecast:

500mb flow will become west-northwest from Saturday through Monday with a cold front sagging south out of Central Canada.  There won't be much moisture for this cold front to work with, but a few showers or isolated thunderstorms could flare up during the Afternoon/Evening hours from this weekend into next Monday.  High temperatures on Saturday will be mainly in the 70s with lows Saturday Night in the 40s and 50s.  Highs for Sunday will be in the 60s and 70s with lows Sunday Night mainly in the 40s to around 50 degrees.

5 DAY FORECAST FOR DULUTH/SUPERIOR

.Tonight...  Breezy.  Variable cloudiness.  Patchy fog possible late.  Scattered showers and thunderstorms.  Low 45 to 50.  Wind east at 10 to 20 mph with a few higher gusts.

.Friday...  Considerable cloudiness.  Patchy fog possible.  Scattered showers and thunderstorms.  High 68 to 73 but cooler near Lake Superior.  Wind east to southeast at 10 to 15 mph, becoming southwest for inland locations.

.Friday Night...  Becoming partly cloudy.  Showers or thunderstorms possible before 6 PM.  Low 48 to 53.  Wind west to southwest at 10 to 20 mph.

.Saturday...  Partly cloudy.  High 72 to 77.

.Saturday Night...  Partly cloudy.  Low 48 to 53.

.Sunday...  Partly sunny.  High 65 to 70.

.Sunday Night...  Partly cloudy.  Low 47 to 52.

.Monday...  Partly sunny.  High 65 to 70.

Normal temperatures for Today

High:  68 degrees
Low:  45 degrees

Friday's Pollen Forecast:

Tree:    Low
Grass:  None
Weed:  None

Sunrise Tomorrow:  5:17 AM CDT
Sunset Tomorrow:   8:57 PM CDT

Tim