Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 357 PM EDT Mon Oct 09 2017 Valid 00Z Tue Oct 10 2017 - 00Z Thu Oct 12 2017 ...A threat for severe weather exists across southeastern Kansas/eastern Oklahoma... ...Heavy rainfall with a potential for flash flooding possible over sections of eastern Iowa into Illinois through tomorrow... ...Numerous daily record warm minima to be broken from the Mississippi River eastward... A compact upper trough currently swinging through the Four Corners region will be a focus for showers and thunderstorms across sections of the Southern/Central Plains. The best focus should be in close proximity to a surface wave moving through southeastern Kansas/northeastern Oklahoma. A moist unstable air mass in conjunction with energetics with the passing trough will invigorate strong to severe thunderstorms later this afternoon/evening. The latest outlook from the Storm Prediction Center suggests all severe weather types will be possible with tornadoes and large hail being the initial threats. As this system accelerates toward the Middle Mississippi Valley on Tuesday, the surface low is forecast to weaken but will still remain a focus for organized heavy rainfall. During the next couple of days, a broad area of 1 to 2 inches of rain is expected from far eastern Iowa into sections of northern/central Illinois. There will be an inherent risk for flash flooding within any of the more intense bands of precipitation. As the system advances toward the Great Lakes, the attendant cold front will bring an end to the extended period of warmth to many locations east of the Rockies. In advance of this upper trough, the air mass in place has brought conditions more reminiscent of summer than the second week of October. Dew point temperatures pushing into the 70s will remain a fixture in the forecast accompanied by highs in the 80s as far north as the Mid-Atlantic. Many daily records may be broken for the mild overnight low temperatures expected. Dozens of locations east of the Mississippi River may see records tied or broken the next couple of nights. On Tuesday morning, the warmest minima for October 10th in Boston, Massachusetts is 64F while the forecast suggests upper 60s are likely. In terms of precipitation, the initial threat from what is post-tropical cyclone Nate will end across New England later this evening. However, while less organized in nature, some scattered showers are possible ahead of the upper trough moving through the Middle Mississippi Valley and Great Lakes by mid-week. On the converse of the warmth over the eastern United States, widespread freeze and hard freeze warnings are in effect from the Central High Plains northward to the Canadian border. This is in response to the expected lows in the upper teens to 20s tonight with an expected warm up on the order of 10 degrees by the following night. Elsewhere, a strong upper trough sweeping through the Pacific Northwest on Tuesday will bring precipitation to the Washington/Oregon Cascades via a moist upslope flow. As the trough sweeps inland, some wintry precipitation is possible across the higher elevations of central Idaho. Rubin-Oster Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php