Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 453 AM EDT Wed Jun 19 2013 Valid 12Z Wed Jun 19 2013 - 12Z Fri Jun 21 2013 ...An anomalous upper cyclone will bring unsettled conditions to much of the Upper Intermountain West/Northern Rockies... ...Below normal temperatures should prevail over much of the northeastern states... The key feature impacting the nation this week is a deep upper cyclone which will slowly migrate toward the east during the next couple of days. The cold air aloft will initiate numerous showers over the northwestern states with a better focus along the frontal zone. The strongest vertical lift should generally straddle the international border which will coincide with where the heaviest rainfall is expected. Through Thursday morning, a threat for flash flooding exists over sections of Northern Idaho and into Northwestern Montana. Additionally, some of the storms may become severe, particularly near the main surface low which is where the better combination of lift and instability will reside. The threat for severe weather should gradually shift eastward in response to the slow moving upper low with the Northern Plains/Upper Midwest getting in on the action by Thursday. An additional impact from this powerful system is the gusty winds in response to the tightening pressure gradient. The breezy conditions combined with a hot and dry air mass will enhance the wildfire danger across sections of the southwestern U.S. and into the Four Corners Region. Looking out east, a surface boundary will have nosed as far south as the Gulf Coast region which will allow a large surface high to build to the north. This should provide tranquil weather to much of the northeastern tier given the strong subsiding motion under the influence of high pressure. Adequate conditions for radiational cooling will be in effect overnight with lows able to dip into the 40s across the Great Lakes and into the northeastern U.S. With the frontal zone anchoring the Gulf Coast, much of the threat for rainfall will exist over the southeastern states the next couple of days. Of course the better activity will coincide with the peak heating of the day with thunderstorms weakening into the overnight hours. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php