July 22nd, 2014
Corn Belt – There are no major changes to the forecast this morning. As warm air builds across the Corn Belt, we are already seeing the results of our next approaching cold front in the upper Midwest this morning. AS expected, showers and thunderstorms are firing off over northern WI and we have seen a few showers aback through southern MN. This front will move through the remainder of the Corn Belt through tomorrow afternoon, so it looks to move just a bit faster than yesterday’s outlook. Rains also do not look quite as impressive over a large part of the region, mostly under half an inch. Coverage should remain around 80%, though.
Cool air begins its push into the region following this front, but will initially be focused on the eastern half of the Corn Belt. This cool air should not be confused with the cool outbreak for next week…but rather just an initial pull back from the heat. Another frontal boundary pushes into the western Corn Belt for Friday, and moves east into the weekend. This brings quarter to three quarter inch rains to the region with coverage at 70%. Then for Sunday into Monday we start to see the cool Canadian air sag south into the region.
Temperatures will be below normal all of next week as cool air parks over the region. Models are drier for the period, with the only precipitation being over the far eastern Corn Belt early in the period – Monday – and generally being under half an inch. Warm air will start to build into the far western part of the Corn Belt around the 2nd, but will not control the region completely until the following week. With the slight extension of the cool air duration next week, we are shifting our extended period pattern back a few days…still allowing for some precipitation but a day or two later than yesterday’s outlook. As the warm air builds, we should see a general increase in shower/thunderstorm action due to instability, but the next good frontal boundary likely will not emerge until around the 6th, with half to 1 inch rains. The period from the 7th through the 11th looks to be warm and dry
Plains – Models are taking a drier approach to the region in a fashion similar to the Corn Belt…there is still moisture around, but it’s not overly impressive. The surface map this morning showers a few showers and thunderstorms close in to the cold front moving through DS and into western NE. The big question is…how long do those hold together. Models would suggest that they really don’t, and rain chances do not look spectacular over the central and southern plains in the days ahead. That goes along with our thinking of the past few days that the heat is just too intense, promoting a cap in the atmosphere that will not allow for much more than isolated convection. In any case, we see heat again today, but then behind the cool front, we should take the most extreme temps and knock them down a few degrees for later in the week. However, we don’t get rid of the heat completely until later in the weekend and next week as cool Canadian air expands over the country.
A front sweeping west to east through the plains Friday into Saturday will trigger light showers from the Canadian border down to I-70…but amounts will be a third of an inch or less, coverage 60%. Then cooler and dry through most of the next week. We see some thunderstorm potential developing on the backside of the high Wednesday night and Thursday next week, mostly over OK, the TX panhandle, and then perhaps up into southwest KS. Rain totals there can be from half to 3 inches, coverage only 40% of the central plains. Models have gone drier for the rest of the period in the plains too.
Southeast/Delta– We still see scattered showers and thunderstorms around over the eastern half of the region from later today through at least Friday. Action is not all that impressive, mostly under a third to half an inch, and coverage at 40%…but its still there. As cold air pushes southward into the Corn Belt, a cool front sags through the region from late next Monday through early Tuesday. This will trigger good rains up to 1 inch through Tuesday night. Coverage will be 7-%. Moisture then lingers for a few days over the eastern third of the region again, promoting combined rains for the period up to 1 inch over GA, FL and the Carolinas…coverage 60%. Scattered showers pop up over the region from the 3rd through the 7th with moisture potential on any given day half an inch or less, but daily coverage only about 30
West – The front for the PNW for tomorrow through Thursday looks more impressive this morning, with rain amounts in the half to 1.5” range over WA and northern ID before the system races northeast into AB. Coverage also looks better in WA and ID at 70%. There can be some scattered moisture farther away from the center over OR and western MN…but amounts there will be under half an inch, and coverage drops off to 40%. The rest of the region looks dry through most of the forecast period. However, we continue to see a nice moisture set up coming out of Mexico, across NM and into CO over the higher elevations. This gets going again later this week and weekend, but looks to be at its peak around the 2nd through the 7th, with daily rains in these areas of a quarter to third of an inch or less. We need to stress that most of the precipitation will be in high elevations, but as long as the moisture is there, some bits and pieces can shift out into valleys and adjoining areas. Temps remain above normal for the region, even as cooler air invades most of the country next week.
Canadian Prairies – Better rains with a system for late this week. We see 1-2 inch rains now for Thursday through Sunday over the region, with coverage at 80%. The heaviest rains will be skewed west over SK and AB early in the period, but all areas see something with this system. Half to 1 inch rains or the 2nd-4th, coverage 70%s. Half inch rains in for the 6th-7th.
Tropics – Tropical depression 2 formed yesterday out of the wave we were concerned about. This thing really has no potential to do much of anything. We will not be surprised to see it named (in slow years…NHC seems to name very marginal storms – we think out of boredom) but in general, there is no thought of this really making much of an impact. This will graze the northern part of the Lesser Antilles over the next couple of days, heading toward Hispaniola by late in the week. However, the storm will be in favorable conditions for development only for a couple more days before being overtaken by dry Saharan air and dust, which will lead to its demise. There should be no impact to the US mainland with what we are seeing so far today. One can make the argument that there is some tropical moisture trying to develop off the FL coast today…but no models are suggesting seriously anything other than just showers and storms over the southeast coast because of this moisture.Filed under Weather | Comment (0)