Week 2 cold anomalies are in store for the northern 1/3rd of the country from coast to coast with near-normal temperatures in the midsection, and anomalously mild in the south from Arizona through southern Texas, along the Gulf coast and Florida. This is a consequence of a persistent jet stream track from the southern Rockies toward the Great Lakes and persistent cool air over the Canadian Praries. It looks like a cool high pressure system will set up over the midwest early in the period (May 2-5) bringing some drying. In the mid section, daily temperatures can and will vary widely but should end up close to average. By the end of week 2 some evidence of a pattern shift is emerging as a blocking ridge develops in many ensemble members along the West coast. Although good for the west, this does infer a return to stormy and cool weather for much of the midwest and NE after May 5.
This week looks to be rather stormy for most of the upper Midwest as a low develops today over southern Colorado and slowly tracks to Wisconsin while, along its cold front, the next low will develop Tuesday over the southern Rockies that will spread heavy rain to the east coast later in the week as some subtropical moisture gets dragged into its circulation. Through the week, severe weather is likely East of a line from NE texas to Milwaukee. A third system is slated to develop over the lee of the southern Rockies Friday and will merge with a low dropping from Manitoba as the strong west to east pacific jet stream remains in control of the overall North Americian weather pattern. This last system will bring a weekend (April 29-May 1) of wet stormy weather to much of the east coast.