April Showers Expected to Continue in Spurts

US map showing precipitation distribution for the 7 days previous to 7 a.m. April 21
Figure 1. NOAA Next Generation Radar (NEXRAD) one-week precipitation estimates ending at 7 a.m. ET April 21.

April Showers Expected to Continue in Spurts April 21, 2016

A well forecasted spring storm system brought significant moisture to a substantial area of the southern and central High Plains this past week.

National Doppler radar estimates (Figure 1) show the heaviest precipitation falling in the more arid regions of the High Plains. Amazingly, little significant flooding was reported across the central Plains as the moisture fell over several days, allowing soils to soak up the moisture like a sponge.

This storm likely saved a rapidly deteriorating wheat crop that had been stressed by the lack of moisture during the past 60 days. Areas that missed out on the initial rounds of precipitation last weekend in response to the surface low moving through the area benefitted from the upper air low that moved across the central U.S. Tuesday and Wednesday.

Climate data from NeRAIN observations show a broad area of 3-8 inches fell from southwest through south central Nebraska, with most of the moisture falling this past weekend. Eastern Nebraska experienced little moisture with the surface low, but widespread rains of 1-2 inches accompanied the main upper air low that moved from New Mexico to the upper Mississippi River basin from Monday through Thursday.

This week’s National Drought monitor for Nebraska showed improved conditions removing the abnormally dry condition label from southwest and south central Nebraska, but keeping it in place for east central and southeastern sections. Further improvements can be expected in next week’s edition as significant moisture didn’t fall until after the Tuesday morning deadline (April 19) for this week’s edition. The big question going forward will be how long will planting be delayed with additional moisture chances on the horizon.

US map showing precipitation distribution for the 7 days previous to 7 a.m. April 21
Figure 2. National Drought Monitor for April 19, 2016. Also see Nebraska drought data and map.

Active Rain Pattern Next 16 Days

The most current forecast models indicate a rather active pattern will continue through at least the next 16 days. There is a slight chance for scattered showers this weekend as low pressure moves across the northern Plains. If this system sags slightly south of current projections, the northern half of the state is the most likely area to receive more than a quarter inch of moisture.

A second system is projected to pass through the state Monday and Tuesday and this system appears strong enough to generate rain, thunderstorms, and isolated severe weather. Weather models currently project totals of 0.5-1 inch for western Nebraska, with totals of 0.25-0.75 inch expected in the eastern half.

A more widespread severe weather outbreak could materialize during the final two days of April. Severe weather is depicted to break out across western Nebraska April 29 and move into eastern Nebraska April 30. If this system verifies, expect another widespread moisture event with the potential to bring an inch or more of moisture to most areas of the state. A dry period is indicated for May 1-5 before models indicate weak chances for moisture May 6-7.

We will need to pay attention to another potential surge of cold air moving southward out of Canada at the end of April. Currently the models bring potential frost/freeze conditions to the northern Plains after the April 29-30 system departs the region. At this time the weather models keep the cold just to our north and confidence in this forecast is low as it has just been in the models for a couple days.

 

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