5/26/15: Finishing May

Over the Memorial Day weekend, rain totals this past weekend were mostly near or under 0.50 inches at the North Dakota Agricultural Weather Network (NDAWN) stations.  The rain impacted along and south of the I94 corridor mainly on Memorial Day.

Memorial Day Rainfall
Memorial Day Rainfall

If you spent the 3 day weekend in southern North Dakota or west central Minnesota you may not be aware of how warm, sunny and pleasant it was across norther North Dakota into northwestern Minnesota it was over the previous three days.

Below is are the high temperatures from the past three days (May 23, 24, and 25, 2015)

May 23, 2015 NDAWN Maximums
May 23, 2015 NDAWN Maximums

 

May 24, 2015 NDAWN Maximums
May 24, 2015 NDAWN Maximums

 

May 25, 2015 NDAWN Maximums
May 25, 2015 NDAWN Maximums

The thermal contrasts were striking this weekend, with northern North Dakota experiencing three above average days, and southern North Dakota experiencing in many cases three below average days.

That warmth that was in northern North Dakota into southern Canada will be moving southward leading to all areas today recording highs in the upper 70s to the lower 80s, although the heat will likely trigger some thunderstorms or showers this afternoon.  Even Wednesday is looking similar, but on Thursday in particular there will be a threat of rain with much cooler air expected on Friday into Saturday.

An area of low pressure is projected to move into western ND on Wednesday night and across the state on Thursday.  This should trigger areas of rain with embedded thunderstorms.  Not an extremely strong storm with rain totals expected like the event on Memorial Day to stay in the near to under one-half inch range, but the embedded thunderstorms will usually produce localized higher totals.

Thursday, 4PM projected surface analysis with precipitation type
Thursday, 4PM projected surface analysis with precipitation type

Behind the storm (rain) on Thursday will come a push have quite chilly air for late May as an area of high pressure with origins in the Arctic will be working into the region Friday through Sunday morning.

Friday
Friday 7 PM CDT Projected Surface Conditions and precipitation type

With cool high pressure, the associated clear sky and light wind from this event, could lead to some scatter frost, especially across northern portions of North Dakota on Saturday morning.

Once that high moves east, a surge of warm air will follow with the potential of much above average temperatures for a least of couple of days to move into North Dakota early next week.  With that surge will also come the prospect of thunderstorms into the region as well.  But June does appear to be starting off warm.

June 2, 7 PM projected 850 mb anomalies via ECMWF WMO-Essential
June 2, 7 PM projected 850 mb anomalies via ECMWF WMO-Essential

Without going into details on the Madden-Julian Oscillation (you can read up on it here, it appears a shift into Phase 2 is in order which for this time of year tends to produce above average temperatures.

MJO through June 8.
MJO through June 8.

What phase and historical statistical corresponding temperatures anomalies for this time of year can be examined below:

MJO Temperature Anomalies per Phase for May, June and July
MJO Temperature Anomalies per Phase for May, June and July

Warm to cool, back to warm is the projection through the middle of next week with main precipitation threats on Thursday and again next week (near June 3-4).

Daryl Ritchison