The cold air is upon us. Temperatures during the weekend went below freezing in the western Plains, but the biggest shot of cold air is moving through the Plains and Midwest behind a cold front April 20.
This shot of cold is likely to cause temperatures to plummet into the 20s Fahrenheit from the Texas Panhandle eastward to the northern Delta and almost all of the Midwest, as noted by freeze warnings for portions or all of 11 states for April 21. Temperatures will moderate some, but frosts are still likely in these areas for April 22 as well. Cold conditions below freezing are possible in the Northern Plains all the way through April 25.
The cold April 21 is likely to cause some damage to winter wheat that is 50% jointed in Kansas, 31% jointed in Colorado, 17% headed in Oklahoma, and 41% headed in Texas. Some more minor damage may be possible in the Midwest where temperatures are not expected to get as cold and the progress is a bit further behind. But still, winter wheat could see some significant damage from the recent and forecast cold spells.
Corn is also at risk. Producers who got out early to plant in Kansas and Nebraska eastward through the Midwest likely did not see the current cold spell coming. Models were slow to jump on the magnitude and scope of the cold air until last week, which was too late for some producers to take notice. Crops that have emerged in these states are at greater risk for replanting needs.
This is the fourth consecutive year that April has had at least one significant widespread freeze event. Previous years have come with large storm systems with heavy snowfall to pull the cold air southward, but this year's event has much less snow. Instead of a wound-up system like previous years, the slow progression southward of a pool of cold air behind a weaker system is the culprit. If temperatures had not gotten lower ahead of this storm system last weekend, we likely would have seen a repeat of a much stronger storm system.
Instead, only a few inches of snowfall will be recorded from Colorado to Ohio, mostly less than 3 inches except for some banding that occurred in central Kansas on April 19-20. The low amounts of snow are not likely to protect wheat and corn from the damaging cold air that settles in its wake for the next two nights.
Fortunately, this event looks to be brief. The cold air settling over Canada looks to retreat next week, being replaced by a much more progressive pattern. This will induce some rising temperatures above normal, followed by temperatures back below normal as systems go by. The magnitude of these colder shots would be much more limited than the one the country is experiencing now.
Models are much more optimistic about normal to above-normal temperatures for the rest of April and into early May. However, DTN long-range forecasters are eyeing the tropics for possible influence on the colder side. An early typhoon in the Pacific is getting attention due to what can follow as its remnants move into eastern Pacific Ocean. Models show the system having little impact, but DTN Long Range Team Lead Nathan Hamblin offers this nugget as the system is set to interact with the upper-level flow in the Pacific:
"If (the typhoon) can speed off quickly within a day or two and get absorbed, it would amplify a trough in the Northwest Pacific, which would pump (up) the downstream ridge (over Alaska). That would increase the odds of another big-ticket cold shot into the central U.S. during the first week of May."
Surely, we will have our eyes on Typhoon Surigae during the next few days and see if it does indeed pose a threat for lower temperatures in about two weeks.
John Baranick can be reached at firstname.lastname@example.org
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