Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 313 PM EDT Mon Oct 01 2018 Valid 00Z Tue Oct 02 2018 - 00Z Thu Oct 04 2018 ...Moisture from Tropical Storm Rosa will bring heavy rain and concerns for flash flooding across the Southwest U.S... ...Heavy rainfall and some severe weather is expected for portions of the Great Lakes and the Northeast... Tropical Storm Rosa will be approaching the northern peninsula of Baja California tonight and is expected to weaken to a tropical depression by early Tuesday as it lifts quickly northeast and approaches southwest Arizona. Moisture and energy associated with Rosa will spread well inland tonight through Tuesday across the Desert Southwest and also the broader Four Corners region including the Great Basin, and the Central and Southern Rockies. Heavy rainfall will impact many of these areas and there will be locally significant concerns for flash flooding. The heaviest rainfall amounts are expected to be across the Mogollon Rim of Arizona where storm totals may reach as high as 6 inches. Meanwhile, in the wake of Rosa, there will be a rather strong upper-level low moving toward central and southern California and this will bring cooler temperatures and some locally heavy rain. Much of the focus will be on the coastal ranges, but the unsettled weather will linger through the middle of the week across much of California. Farther north up across the Pacific Northwest, there will be a cold front dropping south across the region and there will be some shower activity associated with this along with a drop in temperatures. In fact, some snow is expected farther east over the higher terrain of northwest Montana as this front crosses the region in association with an upper trough. This same front will be crossing the northern Plains and upper Midwest through Wednesday and some much colder temperatures will filter south from Canada in its wake. Another area that will likely get some heavy rainfall over the next couple of days will be from portions of southern Wisconsin and northern Illinois eastward across Michigan and over toward northern New England through Tuesday night. This will be associated with multiple waves of low pressure advancing east along a frontal zone. This entire system though will exit New England by early Wednesday. Some localized runoff problems and isolated flash flooding will be possible with this event, but there will also be concerns for severe weather along and ahead of the front as it crosses portions of the Great Lakes, upper Ohio Valley and Northeast. Elsewhere, generally dry weather can be expected with temperatures near or a bit above normal, and this will especially be the case across the southern tier of the U.S. east of the Rockies. Some scattered showers and thunderstorms will be possible along the immediate Gulf Coast and over the Florida peninsula, but the remainder of the South should see tranquil weather through the middle of the week. Orrison Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php