Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 201 AM EST Thu Dec 13 2018 Valid 12Z Thu Dec 13 2018 - 12Z Sat Dec 15 2018 ...Heavy rain and mountain snow expected for the northwestern U.S. and strong storm system developing over the Gulf Coast region... A strong upper level disturbance tracking southeastward out of the Rockies and across the southern plains Thursday morning is resulting in the sustenance of a strong surface low over Texas and Oklahoma. This will be the next major weather system to affect the southern tier of the U.S. from Texas to the East Coast. The surface low becomes well organized by Thursday night across the ArkLaTex region with an anomalous upper level low present. This low pressure system will be multi-faceted with various weather impacts anticipated. Widespread moderate to heavy rain is expected to develop from northeast Texas to southern Illinois, and another area of numerous showers and thunderstorms across the central Gulf Coast region and extending eastward to the southeast U.S. coast, with the potential for 1 to 3 inches of rain for some areas and isolated instances of flooding may be possible. Some strong thunderstorms are also expected in the warm sector of this low from southeast Texas to northern Florida. On the backside of the surface low, strong winds are expected across the western High Plains on Thursday owing to the strong pressure gradient that develops between the low and the large surface high over the Rockies, with some gusts in excess of 60 mph possible. There will also be fire weather concerns across parts of southern Texas due to the combination of windy conditions and much lower humidity levels. There is even some snow in the forecast between Lubbock and Dallas for Thursday night with the potential for a few inches of snow for some locations. Across the Pacific Northwest, two storm systems will be affecting the area. The first one will be a stationary frontal boundary with strong onshore flow across western Washington and Oregon. Heavy mountain snow for the northern Cascades and possible flooding for the Olympic Peninsula are expected given several inches of rain are expected for upslope locations by Thursday evening. A brief lull in precipitation intensity is expected Thursday night in advance of another organized storm system that is forecast to reach the Pacific Northwest on Friday. This will produce another significant round of rain and mountain snow, though not as heavy as the ongoing event, with falling snow levels in the wake of the cold front Friday into Saturday. Farther east across the north-central U.S., down-sloping flow will allow high temperatures to warm into the 30s and 40s, roughly 10 to 20 degrees above average for the end of the week. D. Hamrick Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php