Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 518 PM EDT Mon May 27 2013 Valid 00Z Tue May 28 2013 - 00Z Thu May 30 2013 ***Much warmer for the Eastern U.S. later this week*** ***Stormy weather from the Plains to the Upper Midwest*** ***Showers and cool weather for the Pacific Northwest*** After a very pleasant Memorial Day weekend across much of the Eastern U.S., a pattern change is in the works that will bring much warmer and more humid conditions by mid-week. A big warm front is forecast to lift northeastward through the Ohio Valley and into New England by Wednesday afternoon. The surface high pressure that provided the wonderful weather over the weekend will now exit to the western Atlantic Ocean, and southerly flow around this high will allow for the warm to hot conditions to arrive. A round of showers and storms is likely with the passage of the warm front. Active weather is forecast to continue over the nation's mid-section through Wednesday as a couple waves of low pressure traverse the Plains and into the Upper Midwest. A well-defined dryline over western Texas and New Mexico will also serve as a forcing mechanism for thunderstorm development. A few organized thunderstorm complexes are likely from the Central Plains and extending into the western Great Lakes as multiple shortwaves pass overhead, and locally heavy rainfall is possible. Elsewhere, a large scale upper level trough is forecast to persist over the next couple of days over the Inter-Mountain West, with embedded shortwaves pivoting around the base of the trough. Basically what this equates to is showery weather with a few thunderstorms for much of the Pacific Northwest and into the Northern Rockies, along with below normal temperatures for late May. A few showers and storms are also a good possibility for the Florida Peninsula. D. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php