Sunday, February 19, 2017

Record warmth continues, but a pattern change looms by the end of the week

Sunday's high of 67 degrees made it the third day in a row with record breaking warmth!  Incredible considering our highs should be in the middle 30's.  Several more unseasonably warm afternoons are in store before our pattern changes to more of a late winter pattern.

The reason behind the significant warm up has to do a lot with what's happening out west.  A very strong and active jet stream the past several days has brought significant amounts of rain to California.  So much that flash flooding, mud slides and sink holes have become a big problem.  As the jet stream remains very active out west, a blocking ridge of high pressure has settled over the middle of the country.  Numerous record highs were achieved over the southern Plains and Ozarks late last week.  As surface winds shifted around to the southwest in northern Illinois and southern Wisconsin Friday, it pulled the extreme warmth northeast.  With a very little changing pattern through the weekend, the warmth continued Saturday and Sunday.  The lack of snow cover has also played a role in the unseasonable warmth, along with the fact that since January 19th, 90% of the days have been warmer than normal, per the Chicago National Weather Service!

Another strong low out over the Rockies will move into the Upper Midwest Monday evening.  This low is currently bringing severe weather up through central and northern Texas and Oklahoma Sunday evening.  As the low moves closer Monday, rain will begin to fall late Monday evening and night.  The cold front associated with the low will have originated from the Pacific, and not the north.  This means there is very little cold air following the front, pushing temperatures Tuesday back into the low 60's.

Another, but weaker, low passes to the northwest Wednesday afternoon pushing highs back into the upper 60's!  By the end of the week, the wave train of low pressure systems out west finally break down the strong central U.S. ridge.  A fairly strong low pressure system will develop over the middle of the country Thursday and Friday.  And depending upon the track of the low, we could very well end up with thunderstorms Friday afternoon before temperatures drop back below normal for the upcoming weekend. Any snow associated with this low will remain to the north.  A further break down of the jet stream looks to occur by the beginning of March, possibly bringing the chance for snow to kick off the beginning of the month.

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