9/25/15: Warm Weekend, Frost Potential Next Week

A very mild Friday morning as fog in particular was helping to keep the air temperature up this morning.  In theory, the fog should dissipate faster today than it did yesterday.

6:30 AM Temperatures
6:30 AM Temperatures

Maximum temperatures today will be dependent to some degree as to the timing of the fog dissipation, but current indications would suggestion upper 70s to around 80° in eastern North Dakota into northwestern Minnesota, with mid to upper 80s in far western North Dakota.  This map below indicates the potential of 90° along the North Dakota / Montana border which may be a bit optimistic but even a few degrees cooler than that is a very warm day for late September.

Maximums from GFS for Friday, September 25, 2015
Maximums from GFS for Friday, September 25, 2015

Saturday should be in most locations a couple of degrees warmer with much of North Dakota recording a maximum above 80°.    Although the wind in eastern North Dakota should not be all that bad today, western North Dakota where the temperatures will be the warmest, will experience a stiff south wind today.  That same tight pressure gradient will be over much of North Dakota into western Minnesota on Saturday, so although quite warm the next two days, it will come with a strong south wind with gusts over 30 mph anticipated.

GFS projected Maximums for Saturday, September 26, 2015
GFS projected Maximums for Saturday, September 26, 2015

 

A cold front will sweep across the northern plains on Sunday, but probably not arriving in the Red River Valley or Minnesota until late in the day meaning those locations may still get to 80° on Sunday, but otherwise, it will be a much cooler day with maximums in the 70s with some parts of far northern North Dakota perhaps maxing out on the upper 60s.

Sunday, September 27, 2015 Maximums from the GFS (Global Forecasting System)
Sunday, September 27, 2015 Maximums from the GFS (Global Forecasting System)

 

That front will probably produce some rainfall, but it appears scattered and light as there will not be much moisture to work with.  Behind that cold front, an area of high pressure from Canada will move into the state.

1PM Tuesday September 29, 2015 GFS Projected Surface Analysis
1PM Tuesday September 29, 2015 GFS Projected Surface Analysis

 

It is the clear sky, light wind, and cooler air mass in combination with the longer nights that could lead to frost that morning.  The timing of the high would suggest northern North Dakota with the highest potential, then by Wednesday morning the high may be too far east, meaning a return to a southerly wind by Wednesday morning to produce too much frost.  The potential will clearly be there both mornings, but it does not appear at this time that all areas would be threatened on either morning and therefore, probably some location will escape a 32° during this period.  But an update will come on Monday morning on this blog.

Beyond the frost threat, a couple of rain systems toward the middle and end of next week that may be the beginning of a wetter period in early October as has been mentioned in this space for the past few weeks.  Enjoy the weekend.

Daryl Ritchison