Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Thu Jun 28 2018 Valid 12Z Thu Jun 28 2018 - 12Z Sat Jun 30 2018 ...Severe thunderstorms and flash flooding are likely across the north-central U.S. today... ...Locally heavy rainfall possible over coastal New England as well as the southeastern U.S... ...Well above average temperatures are expected from the Rockies eastward to the Upper Great Lakes... ...Critical Risk for wildfire production over the Four Corners the next couple of days... An amplifying upper trough over the Pacific Northwest will continue to migrate eastward toward the Northern Rockies. As this occurs, a surface cyclone should rapidly deepen along the Montana/Wyoming border with eventual progression into the Dakotas by later tonight. This system will advance into a moisture rich air mass full of instability. Such a combination should foster the development of numerous showers and thunderstorms during the peak in the diurnal heating cycle. Many such storms could become severe in nature as suggested by the Storm Prediction Center convective outlook. Currently an Enhanced Risk is in place across far eastern Montana into a majority of North Dakota while scraping the northern extent of South Dakota. Large hail and damaging winds appear to be the primary threats although a few tornadoes cannot be ruled out. Besides the severe mode to the convection, a potential for flash flooding will exist over a similar region with 1 to 2 inches of rainfall expected through early Friday. Of course higher amounts are possible on a more localized scale. A potent disturbance currently lifting toward upstate New York continues to provide ample lift across the northeastern corridor of the U.S. Widespread moderate to locally heavy rainfall is falling over the region, generally in advance of a slow moving frontal zone. Until this boundary exits the Eastern Seaboard, it will remain a focus for organized rainfall through roughly Friday morning. During the next 24 hours, the highest amounts are likely along and east of the I-95 corridor extending from Connecticut northward. There remains a threat for flash flooding issues, particularly where convection trains or repeats. Farther south, the pattern will also be quite active across the southeastern U.S., especially Florida. Ample moisture in place in conjunction with local sea breeze circulations should promote ample thunderstorm growth each afternoon and evening. The highest amounts will likely focus where storm mergers occur which would allow heavier rainfall to persist longer. Given much of the state tends to respond quite well to the heavy precipitation in terms of drainage and absorption, no discernible flash flood risks are evident at this time. With an upper ridge beginning to take a stranglehold on the central U.S. into the Mississippi River valley, temperatures will soar considerably the next couple of days. Local forecast offices have already hoisted up widespread Heat Advisories and Excessive Heat Watches/Warnings generally from I-35 across Kansas/Oklahoma to as far east as lower Michigan. High temperatures the next couple of days will likely be around 10 to 15 degrees above climatology which supports numbers in the mid/upper 90s to possibly near 100 degrees. While no individual hazards are listed across eastern Colorado, highs will easily punch over the century mark today with some daily records likely to be broken. The expected high of 103 degrees would break the previous record of 99 degrees if achieved. Widespread Red Flag Warnings remain in effect over vast sections of the Desert Southwest into the Four Corners region. Hot, dry, and windy conditions should prevail which will maintain rather low relative humidity values. Much of this region has been under a considerable drought as shown by the latest Drought Monitor product. The combination of all these factors has led to a Critical Risk for wildfire production the next couple of days over the mentioned region. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php