5/20/15: The Weekend Rain

It was another frosty morning in many locations with low temperatures near or below freezing in many locations across the North Dakota Agricultural Weather Network (NDAWN).  This appears to be the last morning with temperatures this cold in the short term and considering the time of year, the odds favor in the long-term as well.

May 20, 2015 Minimums
May 20, 2015 Minimums

High pressure with origination source near the Arctic is currently centered over western North Dakota to Nebraska.  As that moves south and east, the low level wind flow will adjust from the northwest to a more west or south direction slowly bringing in warmer air to the area.

8:00 AM Surface Analysis
8:00 AM Surface Analysis

That process will take a few days and with the influence of high pressure, the weather appears dry through Friday will each day slowly warming up.  Yesterday high temperatures were in the 50s to the lower 60s.

Tuesday, May 19, 2015 Maximum Temperatures
Tuesday, May 19, 2015 Maximum Temperatures

Today the maximums should be mainly in the 60s with near 70° in some parts of western North Dakota and perhaps even in the northern Red River Valley.

Wednesday Maximums Projected from the NAM-WRF
Wednesday Maximums Projected from the NAM-WRF

High temperatures on Thursday in turn, should be even warmer with more locations near or slightly above 70°

Maximum Temperatures for Thursday, May 21, 2015 Projected from the WRF-NAM
Maximum Temperatures for Thursday, May 21, 2015 Projected from the WRF-NAM

By Friday an area of low pressure will move out of the southwestern USA and move and reform off the lee side of the Rocky Mountains in Colorado.

low
Projected Saturday Noon Surface Map

From there it is projected to move to the northeast and impact South Dakota and southern Minnesota and points south with the heaviest precipitation.  Some moisture is expected in North Dakota, but this storm does NOT look to be anything like what occurred the past two weekends.  Precipitation amounts under 0.50 inches seem a bit more likely this time and amounts over that would be localized under possible thunderstorms.  Any moisture at this point for most locations is unwanted, but at least this event does not at this time look to be another repeat.  Some scattered light precipitation on Saturday, with Sunday appearing to be the day with the most widespread precipitation.

Clouds may hold temperatures down into the 60s, but any sunshine beginning Thursday through the middle of next week would mean a high in the 70° to 75° range, therefore, overall, most days in turn the high will be 65° to 75° which is at least close to seasonal averages, but no stretch of above average temperatures is foreseen through the rest of the month of May.

Daryl Ritchison