All Weather News

Life Under The Cut-Off Low

4 May 2013, 3:01 pm

The midwest, from upper portions of Minnesota, and down into Texas has been impacted by an area of low pressure that came into the area a few days ago, and never left.  It was brought via the jet stream that dipped down from Canada earlier last week, and by the middle of the week, as we crossed from April and into May, it started to pull back towards Canada and it left this pesky, upper level low.

Here is how the jet stream looked not too long ago.  The jet stream dipped down towards the Gulf of Mexico, bringing about some unseasonably cold air, but has started to move back up north.  In Texas, they had morning low temperatures cold enough to break records in Dallas (39° this morning, average low is 60°) and Waco (34° this morning, average low is 60°).

A high pressure system over the northeast has been acting as a big bumper, making the jet stream flow up and over it.  The pattern, thus by doing this, takes on the shape of the upper case Greek Letter, Omega, and has thereby been labeled as Omega Block.  This high pressure system is nearly stationary, so the weather underneath it has been very mild and sunny while under the cut-off low pressure, the weather has been cloudy, cool, and full of showers.  With the cold air in place across the Midwest and the precipitation falling into it, there has been heavy, wet snow falling as a result of this cut-off low over the course of the past several days.

This satellite and radar image was taken earlier this morning.  Snow was falling down in southwestern portions of Missouri and into northwestern Arkansas.  This is nearly unprecedented, for snow to fall in May in that part of the country.  Joplin, MO has snow falling on it in this image but nearby in Springfield, there was a record set.  There has only been one other time in Springfield, MO, for example, where measurable snow fell in the month of May in that city, since records began in 1888.  It was 6.1″ of snow on May 3, 1929.  So now for May 4th, the city has a new record for the latest measurable snow falling.  In case you are wondering, the latest snow ever fell in the month of May was reporting falling but didn’t measure (also known as a Trace), was May 6th, 1944.

This cut-off low brought about even higher amounts of snow, smashing records, just the other day in portions of Minnesota, Wisconsin and Iowa.  The higher snowfall totals were averaging about 8-18″!  Those are totals you would typically see from a snowstorm in the winter months, or at least, early April.

Here is an image for the snowpack that has fallen across the midwest.  The snow pack in Colorado, western Kansas and western Nebraska fell earlier in the week (April 30-May 1) and came down when the area of low pressure first came into the area.  The higher snowfall amounts (10″-18″+) can be found in the purple swath from Wisconsin to northern Iowa where the area of low pressure’s movement came to a standstill, but the precipitation kept falling.

The snow cover across the upper Midwest is very prominent in these three images.  The most recent snow is to be found in southwestern Missouri and into Northwestern Arkansas, which happened earlier this Saturday morning.

By the end of April, temperatures were getting up into the 60s, 70s and 80s and the city pools in Fort Dodge, IA were opening up for the month of May.  May 1st came around, temps were in the 60s, but by May 2nd & 3rd, temps were in the 40s and 30s, and snow was on the ground.  This snowman, perhaps, wants to take a nice swim, since the pool is open and he is the only one around that would want to use it when the temps are that cold.

In Denver, the tulips were starting to sprout and Spring looked like it was finally showing signs of taking over completely.  Then here comes the latest sign that Winter is still holding on tightly, as snow falls across the area on Wednesday, the first day of May.

And up in Cable, WI, the deck chairs were out and the patio was getting ready for Spring when a fresh coat of heavy, wet snow, came and landed on the area.

On top of snow, there has been unseasonably cold temps moving out of Canada, and down into the southern plains and into the southeast.  Temps have averaged 5-25° below normal from Minneapolis to Raleigh.  But by tomorrow, the cold air will start to fade away as the cut-off low moves out of the central plains and heads into the southeast.

Temperatures are still going to be trending below normal, for Sunday, but not as harsh.  Most cities show a drop of 5-20° with improvements to be found in Minneapolis and Topeka to be some of the highest.

The forecast map for tomorrow is up above and the northeast and the northwest are still going to be enjoying wonderful weather as we wrap up the weekend.  The southwest coastal areas will see clouds gather and temperatures trend a little cooler with a chance for rain to be coming shortly.  The green-shaded areas in the mid section of the country are where temperatures are still going to be trending cooler than normal, from the Twin Cities, to Atlanta.  The southeast and the Mid-Atlantic area will see showers and storms on the move into those areas, bringing about a chance for some flooding situations.

Take care, and enjoy the rest of your weekend!  And remember, the meteorologists are just the messengers.  We didn’t make the weather, but we do apologize for the lousy conditions that have been impacting the Midwest. 😀

Meteorologist Addison Green (twitter: @agreenWNTV)







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