Thursday, March 7, 2013

Patchy fog Tonight-Friday AM; Latest on the potential snow/mixed event Friday Night-early Sunday.

/Issued 3:36 PM CST, Thursday, March 7th, 2013/

*Another complex storm system looks to be setting up for this weekend.  Is it just me, or does anyone else think that these winter storms are becoming trickier and trickier every year.

The next 3 images I'm posting are the 500mb forecasts.  I mentioned a few days ago about the split flow this weekend and it's happening.  There's energy with the Northern jet (NW of Minnesota) and energy within the Southern jet (SW of Minnesota)   (Source, 15z SREF model)

1) Image 1 is valid for Saturday Morning.  The 2 pieces of energy are not phased.

2)  This next image is valid for Saturday Evening.  See how the bundles of energy are beginning to get closer together~Green/Brown colors in these maps.

3)  This final image is valid for Sunday Morning.  The phasing is pretty much complete by this time as the 2 separate pieces of energy absorb into 1 broad trough stretching from the Central Plains to Central Canada.  Pretty cool how this works, and usually the computer models struggle when you have a setup like this, so far they've done pretty well.

Low temperature report for March 7, 2013
Source:  National Weather Service Duluth, Minnesota

Duluth, MN:  -8F
International Falls, MN:  -11F
Hibbing, MN:  -11F
Orr, MN:  -11F
Cook, MN:  -13F
Eveleth, MN:  -11F
Bigfork, MN:  -15F
Aitkin, MN:  -9F
Moose Lake, MN:  -9F
3 E of Wright, MN:  -12F
Northome, MN:  -14F
Embarrass, MN:  -17F
3 E of Orr, MN:  -12F

Today's Weather Summary for Northeast Minnesota and Northwest Wisconsin

Partly to mostly sunny skies prevailed Today with highs ranging from the middle 20s to middle 30s.  Winds were out of the south or east at 5 to 15 mph.

Today's Upper Level Analysis

500mb troughs covered the Western U.S. and Northeast U.S., an upper level ridge was over the Plains and Upper Midwest while a pretty strong disturbance moves east out of Southern Saskatchewan per water vapor satellite imagery.  850mb temperatures as of 3 PM ranged from 0 to -4C in Western, Central and Southern Minnesota to -6C in Northern Minnesota.

*Minnesota snow depth map as of March 7, 2013.  Only the far Southwest part of Minnesota has little to no snow on the ground.  The rest of the state has at least 4-8" with 12-24" of snow on the ground over a large portion of Central, Western and Northern Minnesota.  (Source, MNDNR)

Forecast Discussion for Northeast Minnesota and Northwest Wisconsin

Short Term Forecast - Confidence:  High.

Tonight (March 7th)

High pressure will be centered to our east while a cold front and upper level disturbance remains to our northwest.  Partly to mostly cloudy skies are expected Tonight.  Patchy fog and or light freezing drizzle may develop Overnight, this shouldn't be a widespread event, however.  Lows will mainly be in the teens, but some single digits can't be ruled out depending on how long skies stay clear.  South or east winds will continue Tonight at 5 to 15 mph.

Friday and Friday Night (March 8th)

Low pressure and a strong upper level trough will move into the Rockies which will set up a southwest flow from the Plains through the Upper Midwest.  Gulf moisture will be pushing north into our area during this period as a cold front and H5 trough remain off to our west.  Mostly cloudy skies are forecast this period with patchy fog and or light freezing drizzle a possibility Tomorrow into Tomorrow Evening, but again this doesn't look to be a widespread event.

Steadier and more widespread snow, sleet and freezing rain should move into the Northland late Friday Night, this is when travel conditions may become quite hazardous.

Temperatures will be in the 20s and 30s this period with south or east winds at 10 to 20 mph.

Extended Forecast - Confidence:  Medium.

Saturday through Monday (March 9th-11th)

An area of low pressure will move out onto the Central Plains on Saturday before it tracks east or northeast and toward the Central Great Lakes on Sunday.  There will also be 2 upper level troughs which will sort of phase together by Sunday.  One trough approaches from the NW and the other from the W/SW.  The merging should occur somewhere over the Upper Midwest and Great Lakes this weekend.

Precipitation in the form of snow, sleet and freezing rain is forecast to continue Saturday into Saturday Night in Northeast Minnesota and Northwest Wisconsin as this complex weather system moves through.  Note:  It's possible that the precipitation will change over to mainly rain/drizzle at times Saturday Afternoon, especially in Northwestern Wisconsin the way it looks now.

Flurries and snow showers could linger into Sunday as the upper trough and area of low pressure exit to our east.  Dry weather returns Sunday Night and Monday.

High temperatures will mainly be in the 30s on Saturday and in the 20s and 30s for Sunday and Monday.  Lows Saturday Night will be in the 20s and 30s.  Lows Sunday Night in the single digits and teens.

Note:  It's still a little early to get a handle on just how much snow or ice accumulation will see in the Northland Friday Night into early Sunday, but the potential is there for several inches of snow and sleet accumulations (4+")  With ice accumulations possibly reaching .10-.25", especially around the Brainerd Lakes to Aitkin to Moose Lake corridor.  Winter weather advisories, watches or warnings will likely be issued for some parts of our area by the National Weather Service during the next 24 hours.  Stay tuned!

*Watch/warning map per NOAA/NWS.  A winter storm watch has been issued for Friday Night through Sunday Morning for a part of Western and Central Minnesota (dark blue areas)  Winter weather headlines will likely be expanded to include other parts of Minnesota by this time Tomorrow.  Light green area in Southeast Minnesota represents an Hydrologic outlook due to the combination of snow melt and rain this weekend which may lead to some flooding down in that area.

*4" or greater snowfall probability forecast for Saturday-ending at 6 PM.  (Source, WPC)

Green=Moderate risk for at least 4" of snow.
Blue=Slight risk for at least 4" of snow.

*.25" or greater ice accumulation forecast for Friday Night and Saturday per WPC.

Green=Moderate risk for at least .25" of ice accumulation.
Blue=Slight risk for at least .25" of ice accumulation.

Long Range Forecast - Confidence:  Medium.

(March 12th-17th)

A gradient pattern could develop most of next week with multiple low pressure disturbances moving east-southeast out of Western Canada.  There could be some snow around our area at times next week depending on the track of these disturbances.  A larger trough/storm may develop over the Western U.S. next weekend (16th-17th)  Near to below average temperatures are forecast through this period.


.Tonight...  Partly to mostly cloudy.  Low 13 to 18.  Wind east to southeast at 5 to 15 mph.

.Friday...  Considerable cloudiness.  High 30 to 35.  Wind south at 10 to 15 mph.

.Friday Night...  Snow, sleet or freezing rain developing after Midnight.  Mostly cloudy.  Low 25 to 30.  Wind east to southeast at 10 to 15 mph.

.Saturday...  Occasional snow, sleet or freezing rain.  Areas of fog possible.  Some snow and sleet accumulation expected.  High 30 to 35.

.Saturday Night...  Some snow with additional accumulations possible.  Low 20 to 25.

.Sunday...  Flurries.  Mostly cloudy.  High 30 to 35.

.Sunday Night...  Partly to mostly cloudy.  Low 5 to 10.

.Monday...  Partly sunny.  High 25 to 30.

Normal temperatures for Tomorrow

High:  31
Low:  14

Sunrise Friday:  6:35 AM CST
Sunset Friday:   6:05 PM CST


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