June 11 through June 17 Weather Forecast

This was my piece in the Crop and Pest Report posted today.  Overall a good forecast, with the possible exception of next Tuesday/Wednesday depending on the track of a storm, which of course this far out,  is somewhat uncertain.


The June 11 through June 17 Weather Forecast

 After a prolong period with the upper-level wind flow frequently having a southwesterly component over the Northern Plains, in the past few days that mean flow has been more from the west or northwest allowing for a break in the heavier precipitation.   As low pressure systems move in from the southwest they have a longer period of time to pull Gulf of Mexico moisture into the area.  A high percentage of the widespread heavier precipitation events that North Dakota and northwestern Minnesota receive, in any season, can be attributed to storm systems coming in from the southwest.

In the near term, today (Thursday) and Friday, the main storm track will be south of our immediate area.  Southern South Dakota, southern Minnesota and points south in Nebraska, Iowa and southern Wisconsin could record excessive rain amounts from a series of thunderstorms expected in those locations.  Although southern North Dakota in particular may record some rain from that system, amounts look very light.  Otherwise, little if any precipitation is expected until Sunday.

This weekend, a large high pressure ridge in the Jetstream is expected to develop over Alaska (warm air surge) that will force a cold front through North Dakota Saturday Night into Sunday.  Not only will that front bring below average temperatures into the region early next week but also trigger some hit and miss thunderstorms.   As that ridge intensifies in Alaska, an area of low pressure should form in the Pacific Northwest, dig into the Rocky Mountains then move into North Dakota in the Tuesday/Wednesday time frame.  Because this will redevelop the southwest flow previously mentioned, that projected storm will have heavier rain potential, plus a prolong period of clouds, cooler temperatures, and high low level relative humidity if it develops as expected.

Projected growing degree days (GDDs), base 34°, 44° and 50° for the period June 11 through June 17, 2015 are presented below.  Because of the overall cooler conditions foreseen early next week, the total GDDs are projected to be 10-15% lower than this past 7 day period. The period from June 20-25 is anticipated to have average to above average temperatures once again.

GDDs Base 34
GDDs base 44
GDDs base 50

Daryl Ritchison