Wednesday, June 29, 2011

6/29/11: Wednesday's Weather Report

Issued at 3:37 PM CDT, Wednesday, June 29th, 2011

Weather History:

On this date in 1992:  A record low temperature of 40 degrees occurred at Duluth, Minnesota.

WEATHER HEADLINES:

-Few showers/thunderstorms possible into Thursday A.M.
-Extreme instability and tropical like dewpoints Thursday
-Severe risk if thunderstorms can develop Thursday Night
-Excessive heat advisories/warnings hoisted for portions of Minnesota for Thursday
-Risk for showers/thunderstorms once again on Friday

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Today's Weather:

High pressure of 1018mb was centered in Eastern Illinois This Afternoon with deep low pressure of 996mb in Southcentral Alberta Province with a 1000mb low along the Montana-North Dakota border.  Broad southerly flow was occurring Today across the Upper Midwest with increasing amounts of humidity, especially away from Lake Superior.  Afternoon dewpoints were in the 50s and 60s across our area with PWS ranging from 0.80-1.00".  Sunny to partly cloudy skies covered the area Today with high temperatures in the 50s to lower 60s at the head of Lake Superior to the 70s and lower 80s elsewhere.  Winds Today were out of the south or east at 10-20 mph.

Today's Upper Level Analysis:

500mb troughs were in place across Eastern Canada and the Western U.S. while an upper level ridge extends from the Upper Midwest through the Central-Southern Plains per RUC model analysis.  A lot of warm air was pushing NE out of the Rockies and Western High Plains Today with 3 PM 850mb temperatures ranging from +34 degrees C at Denver, Colorado to +30 degrees C at Pierre, South Dakota to +20 degrees C at Bemidji, Minnesota.

Tonight:

Southerly low level jet up to 35 knots will continue to advect deeper moisture into our area Tonight with a big increase in elevated CAPE also occurring with values of 1500-3000 j/kg forecasted Overnight.  Partly-mostly cloudy skies will be found in our area with a few showers or thunderstorms possible mainly late.  These storms if they develop would be forming to the northeast and east of the +14 degree C 700mb temperature contour which will be spreading east out of the Northern Plains Tonight.  The threat for severe weather is low for Tonight, but occasional downpours and lightning strikes could occur.  Lows Tonight will be in the 50s near Lake Superior and generally in the 60s elsewhere.  Winds Tonight will be out of the south or east under 20 mph.

Thursday:

Partly to mostly sunny skies will occur Tomorrow with a risk for a few showers or thunderstorms, mainly before Noon.  CAPE of 2000-4500 j/kg will be developing in our area on Thursday, but a stout cap consisting of 700mb temperatures of +14 to +16 degrees C will advect into the Upper Midwest Tomorrow which should put a lid in any thunderstorm development after Tomorrow Morning.  High temperatures on Thursday will be in the 80s and 90s but it will be cooler near Lake Superior.  Dewpoints will climb into the 60s and 70s with PWS around 1.25".  Afternoon heat indices could soar into the 90s for portions of the Northland, away from Lake Superior.  Note:  Heat indices of 95 to 110 degrees will be found in parts of Western, Central, Eastern and Southern Minnesota Thursday Afternoon.  Winds Tomorrow will be out of the south or east at 10-25 mph.

Thursday Night:

A warm front will lift northeast into the area with high amounts of instability, decent shear, and deep moisture in place across our area, but a strong cap will also be in place.  It's uncertain whether or not thunderstorms will be able to develop due to the cap's strength, but if they do, they certainly could turn severe with large hail and damaging wind being the main hazards along with heavy downpours and dangerous lightning.  Lows Thursday Night will be in the 60s and 70s, cooler near Lake Superior.  Winds will be out of the south or east under 20 mph.

Extended Forecast:

Low pressure will be passing by well to our northwest-north on Friday, a cold front attached to this low will be moving across Northern Minnesota and Northwest Wisconsin for Friday and Friday Evening.  Strong instability and decent shear will be in place across our area out ahead of this cold front, but a cap will also continue...A few showers or thunderstorms which could turn severe are a possibility in our area for Friday and Friday Evening.  Dry weather is expected Friday Night through Saturday Night with lowering humidity in wake of Friday's cold front.   High temperatures will be in the 80s to lower 90s on Friday, except for cooler temperatures near Lake Superior.  Lows Friday Night will be in the 50s and 60s.  Highs on Saturday will be in the 70s and 80s with lows Saturday Night in the 50s to around 60 degrees.

5 DAY FORECAST FOR DULUTH/SUPERIOR

.Tonight...  Partly cloudy.  Isolated showers or thunderstorms possible after 2 AM.  Low 55 to 60, cooler near Lake Superior.  Wind east to southeast at 10 to 15 mph.  Chance of rain 30%.

.Thursday...  Humid.  Isolated showers or thunderstorms during the Morning.  Partly sunny.  High 73 to 78, cooler near Lake Superior.  Wind east to southeast at 10 to 20 mph.  Chance of rain 20%.

.Thursday Night...  Humid.  Partly cloudy.  Isolated showers or thunderstorms possible Overnight.  Low 60 to 65, cooler near Lake Superior.  Wind southeast at 5 to 15 mph.  Chance of rain 20%.

.Friday...  Humid.  Partly sunny.  Showers or thunderstorms possible.  High 80 to 85.  Chance of rain 20%.

.Friday Night...  Turning less humid.  Showers or thunderstorms possible early.  Partly cloudy.  Low 57 to 62.

.Saturday...  Partly cloudy.  High 78 to 83.

.Saturday Night...  Partly cloudy.  Low 55 to 60.

.Sunday...  Partly sunny.  High 75 to 80.

Normal temperatures Today

High:  74 degrees
Low:  52 degrees

Thursday's Pollen Forecast:

Grass:  Moderate
Tree:    None
Weed:  None

Sunrise Tomorrow:  5:18 AM CDT
Sunset Tomorrow:   9:07 PM CDT

Tim