Issued at 4:16 PM CDT, Wednesday, August 31st, 2011
Rainfall report for Tuesday-Wednesday Morning, August 30th-31st, 2011
Source: National Weather Service Duluth, Minnesota
Duluth, MN: 0.38″
International Falls, MN: 0.35″
Grand Marais, MN: 0.23″
Hibbing, MN: 0.23″
Hayward, WI: 0.36″
3 miles northeast of Nisswa, MN: 0.26″
4 miles west of Clam Lake, WI: 0.24″
Very impressive Mid-Atlantic rainfall totals this month (totals and avg. thru the 30th)
Source: National Weather Service
Philadelphia, PA: 19.31″. Average: 3.40″
Trenton, NJ: 14.85″. Average: 3.98″
Atlantic City, NJ: 11.11″. Average: 4.01″
Central Park, NY: 18.95″. Average: 4.44″
WEATHER HEADLINES:
*Low clouds, fog and drizzle continues Tonight and possibly into Thursday for some areas
*Chance for showers and thunderstorms late Tonight-early Friday
*Severe and heavy rain threat for Thursday and Thursday Night
*Labor Day weekend looks generally dry, but a couple hours of showers are possible on Saturday
Forecast Discussion for Northeast Minnesota and Northwest Wisconsin
Today’s Weather:
A warm and moist advection pattern is well underway with a large area of stratus clouds along with areas of fog and drizzle in place over our area Today. High temperatures on this final day of August 2011 were in the 60s to around 70 degrees with upper 50s at the head of Lake Superior. Dewpoints Today ranged from the mid 50s to mid 60s and winds were out of the east or southeast under 20 mph.
Today’s Upper Level Analysis:
A fairly strong disturbance which brought the area some rain on Tuesday was exiting to our north-east This Afternoon per water vapor satellite imagery. A potent upper level trough was digging south-east across the Pacific Northwest and Northern Rockies with a southwest H5 flow developing ahead of this trough across the Northern Plains.
Tonight:
Low clouds will remain in place in our area along with patchy fog and drizzle, some of the fog could become dense at times with visibilities falling to around one quarter mile. A warm front currently in Southern Minnesota will remain in that general area during the night while low pressure in Northern Wyoming heads into the Northern Plains Overnight. Southerly winds ahead of this system will continue to feed warm and moist air into our area. Instability will also be on the increase Tonight north of the warm front as elevated CAPE climbs to around 1000 j/kg. The threat for showers and thunderstorms is on the low side Tonight due to a cap (warm layer of air aloft) which will strengthen during the night, however, a few elevated thunderstorms could develop late Tonight especially in Northcentral Minnesota. Low temperatures Tonight will be in the 50s and 60s with east or southeast winds under 20 mph.
Thursday and Thursday Night:
A warm front will lift northeast into Eastcentral Minnesota and Northern Wisconsin while a cold front moves east out of the Dakotas Thursday Morning…This boundary will reach the International Falls and Brainerd Lakes area by late Thursday Afternoon…And will move through Northeast-Eastcentral Minnesota and Northwest Wisconsin Thursday Night.
A warm, moist and potentially very unstable airmass will be found across the Upper Midwest on Thursday with CAPE ranging from 1500-4000 j/kg and Lifted Indices from -3 to -8 degrees C. Dewpoints are forecasted to be in 64-73 degree range with PWS of 1.25-1.75″ and 850mb td’s of +14 to +20 degrees C.
A strong cap is still expected to lift northeast into our area through Thursday Evening with 700mb temperatures of +12 to +14 degrees C, but there have been some trends per recent model data that the cap may weaken just enough to allow for the development of scattered thunderstorms by late Thursday Afternoon or early Thursday Evening from Northcentral into Eastcentral Minnesota, and possibly into Northwestern Wisconsin…Should the cap not weaken, then the threat for showers and thunderstorms would hold off until late Thursday Evening, or most likely during the Overnight hours.
Note: There may also be a round or two of showers and thunderstorms affecting mainly Northern Minnesota Thursday Morning on the nose of the approaching cap.
The potential for severe thunderstorms does exist for Thursday and Thursday Night with plenty of instability, warm and moist air in place…This combined with 30-50 knots of 0-6 KM SHEAR and EFFECTIVE BULK SHEAR in conjunction with a 65 knot mid level jet and a 80-110 knot upper level jet from the Northern Plains to Red River Valley will support a severe risk. Large hail and damaging winds appear to be the greatest threats at this time, but there could also be an isolated tornado threat if storms can develop between 3-9PM Thursday. 1KM HELICITY is forecasted to range from 100-200 m2/s2 with 1KM EHI values of around 2 per 12z model data.
High temperatures on Thursday will be in the 70s and 80s with 60s at the head of Lake Superior. Low clouds, areas of fog and drizzle should burn off in most areas on Thursday, but the exception might be around Lake Superior unless the marine layer can weaken during the day.
Low temperatures Thursday Night will be in the 50s in far Northern Minnesota with 60s to lower 70s elsewhere. Winds Tomorrow will be from the south or east at 10-20 mph. Winds Tomorrow Night will be out of the north, east or south under 20 mph.
Extended Forecast:
Low pressure and cold front will exit to our east Friday Morning…Some lingering rain showers are possible in Eastern Minnesota and Northern Wisconsin before Noon Friday, thereafter high pressure builds in with dry weather Friday Afternoon into Saturday Morning. High temperatures on Friday will be in the 60s and 70s with lows Friday Night in the 40s and 50s. A quick moving cold front will drop southeast through our area on Saturday…This system looks like it may be fairly vigorous, but won’t have much moisture to work with due to the speed of it. A line or two of showers and isolated thunderstorms will probably occur Saturday Afternoon and Evening in Northern Minnesota and Northwest Wisconsin as this front moves through. Dry weather should then return to the area Saturday Night through Labor Day Monday as high pressure builds into the Upper Midwest. High temperatures on Saturday will be in the 60s and 70s with lows Saturday Night in the 40s and 50s.
5 DAY FORECAST FOR DULUTH/SUPERIOR
.Tonight… Low clouds…Areas of fog and drizzle. Low 55 to 60. Wind east to southeast at 10 to 15 mph.
.Thursday… Areas of low clouds. Patchy fog and drizzle also possible. Partial sunshine may develop during the Afternoon. Showers or thunderstorms possible. High 70 to 75 but cooler near Lake Superior. Wind southeast at 10 to 15 mph. Chance of rain 30%.
.Thursday Night… Showers or thunderstorms. Mostly cloudy. Low 60 to 65. Wind south to southeast at 5 to 15 mph becoming northwest late. Chance of rain 60%.
.Friday… Scattered showers possible during the Morning. Variable cloudiness. High 70 to 75. Chance of rain 30%.
.Friday Night… Partly cloudy. Low 48 to 53.
.Saturday… Partly sunny. Afternoon showers or thunderstorms possible. High 70 to 75. Chance of rain 30%.
.Saturday Night… Showers possible early. Partly to mostly cloudy. Low 48 to 53. Chance of rain 30%.
.Sunday… Partly cloudy. High 63 to 68.
Normal temperatures for Today
High: 71 degrees
Low: 52 degrees
Thursday’s Pollen Forecast:
Weed: Low
Grass: None
Tree: None
Sunrise Tomorrow: 6:28 AM CDT
Sunset Tomorrow: 7:49 PM CDT
Tim