Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 AM EDT Wed Jun 27 2018 Valid 12Z Wed Jun 27 2018 - 12Z Fri Jun 29 2018 ...Severe thunderstorms and flash flooding possible over the north-central U.S. on Thursday... ...Unsettled weather in store for the northeastern U.S. during the next couple of days... ...Well above average temperatures to prevail across the middle of the country... ...Increasing threat for wildfire production over the southwestern states and Central Great Basin... An active weather pattern ahead across the nation given a wide variety of hazards in play. While considerable activity will unfold on Wednesday, the more significant event should wait until the following day. Amplifying flow across the Pacific Northwest should lead to a marked strengthening of a surface cyclone swinging across the Northern High Plains by Thursday afternoon. A moist and unstable air mass across the north-central U.S. will favor the development of numerous showers and thunderstorms. Based on the latest Storm Prediction Center outlook, some of the convection may become severe in nature with an associated flash flood risk. An Enhanced Risk for severe thunderstorms is currently in place over vast sections of North Dakota with large hail and damaging winds the primary threats. Additionally, the mentioned hydrologic impacts are likely as well given the strip of up to 2.50 inches of rainfall advertised across North Dakota into northwestern Minnesota. Details of course will change during the next day, but locally heavier amounts are definitely plausible over this region. An upper trough sweeping across the Great Lakes and into New England the next couple of days will maintain a period of unsettled weather. A threat for severe thunderstorms is noted over sections of the Lower Ohio and Upper Tennessee Valleys given favorable parameters in place. Farther north, a broad shield of showers and thunderstorms should keep areas wet generally east of the Mississippi River. On a larger scale, the heaviest rainfall will likely unfold over New England into the Upper Mid-Atlantic given closer proximity to the stronger dynamics within the trough. In addition to the precipitation, slightly below average temperatures are in the forecast as highs remain in the 70s to lower 80s although Maine can anticipate upper 60s on Thursday. As an expansive upper ridge begins to build from the Four Corners eastward into the middle of the country, a modest heat wave will take shape. A number of local forecast offices have hoisted up Heat Advisories and even an Excessive Heat Watch across eastern Missouri and western-central Illinois. Widespread highs in the 90s are anticipated underneath this upper ridge while even some pockets of 100 to 105 degree readings are possible. While widespread daily records should not be broken, some areas of eastern Colorado could achieve this feat on Thursday, specifically Denver and Pueblo. With hot, dry, and gusty winds expected across the southwestern U.S. and Central Great Basin, there will be an appreciable threat for wildfire production. The Storm Prediction Center fire weather outlook notes a couple areas in the critical threat level. The resultant low relative humidity air mass has led to a broad swath of Red Flag Warnings from Nevada eastward into Utah and western Colorado. Some of these regions overlap locations of extreme to exceptional drought based on the map published a week ago. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php