The Wednesday morning radar shows a cluster of heavy storms and moderate rain over far eastern portions of Oklahoma …far Northwest Arkansas …and the southwest third of Missouri with additional scattered showers over central Oklahoma and over the Texas panhandle. A second area of precipitation consists of moderate rain over the eastern third of Iowa …far northwest Illinois …the western half of Wisconsin and southeastern Minnesota. To the north the precipitation over the northern half of Minnesota is falling as snow which extends into the far eastern 25% of North and South Dakota. FAST EAST LOADING RADAR
Once again very cold temperatures for this time of year were found across eastern Montana … eastern Wyoming with Max temperatures in the 30s. These temps also cover all of Dakotas with 40s over Northern Minnesota and the northern half of Nebraska. Max temperatures stayed in the 50s over southern Nebraska … northwest Iowa and central Minnesota and 60s over eastern Colorado ….most of Kansas .. northern Iowa and …southeast Minnesota. 70s were common across Wisconsin …all of th ECB .. into Michigan Kentucky Tennessee and the Texas panhandle… with 80s over most of Oklahoma the remaining portions of Texas ..Louisiana Arkansas … Missouri …Mississippi …Alabama …and Georgia.
The OFFICIAL 7 DAY Rainfall forecast from NWS is well stunning and smacks of the flood season of 1993. The official forecast LINK has a bullseye of 12 “/350 mm of rain and Northwest Arkansas with a large area of 7-10″/ 175-250mm stretching from all of the remaining portions of Arkansas and eastern Oklahoma …into the southeast portions of Missouri ..far western Tennessee and western Kentucky …into the southern half of Illinois. As you can see large areas of the Deep South and the remaining portion of the Midwest sees major rainfall all the next 7 days with only the Dakotas and Western Minnesota as well as southwestern Texas missing out on the rain.
These 2 maps show a comparison of the next 7 days between the GFS and the European operational models. The thing is 90% of the time the GFS model issignificantly wetter than the European model because of the way these models were developed. It is rather unusual when the European model is as wet in these extreme situations as the GFS. In this case because that is the case … it provides forecasters with extra confidence that in extreme rain event is about to begin across the upper Delta and the heart of the Midwest. The only major difference between in these 2 weather models has to do with the large areas of 8 to 12 inch rains found over the eastern third of Oklahoma the northwest half of Arkansas the southeast half of Missouri into far southwestern Illinois. To see the European model show the same sort of widespread extreme rainfall over the exact same areas is well quite frankly striking and very unusual. The GFS model has a bit more rain over the Iowa than the European model does …and there are some small differences and the amount of rain which falls over Ohio and eastern Indiana. But for the most part the model agreement here is extremely good.
Even the GFS and European ensemble which almost never goes for extreme solutions are in fact showing extreme solution. The GFS ensemble (LEFT) – which is a mean of 21 GFS ensemble members — show a mean of over 8″ 200mm of rain over eastern Oklahoma …the northwest half of Arkansas …central and southeastern Missouri …into the southwestern and central Illinois. The European ensemble is also showing extremely heavy rain with its ensemble mean of 5-7″/ 125-`75mm covering all of Arkansas …the southeast third of Missouri …far southwest Illinois and far eastern portions of Oklahoma.
The European model continues to be most aggressive with a wave of LOW pressure that develops on the stalled front in April 30 May 1. This LOW pressure area tracks into up the Mississippi Valley into the western Great Lakes by May 1. As it does so pulls down late season cold air from central Canada and the European model still producing a significant late season snowstorm that drops anywhere from 3- 6 inches of snow over eastern Nebraska ….northwest 25% of Iowa and 3 to 10 inches of snow over much of Minnesota. Behind this system there will be a widespread major outbreak of much below normal temperatures across all the Plains and the WCB which will last about May 5 or May 6
The pattern is clearly significantly drier in week two but it is not completely dry with the extended models showing some sort of moderate rain event over the heart of the Midwest May 3-4 and again MAY 9-10
If you missed last week’s webinar, you may VIEW A RECORDING.