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    The Second Storm, While Weaker, Will Have More Far-Reaching Impacts Later This Week

    9/30/2013, 8:08:52 AM

    Monday, 11:45 A.M.

    There is little active weather across the country right now. Most places are warmer than normal to much warmer than normal, and pretty dry. The one significant exception to that is the Northwest, where a potent storm rolled into southern Vancouver last night with powerful winds and flooding rains that impacted much of western Washington and brought rain to areas as far south as northwestern California overnight. Aside from that area, though, there was little storminess anywhere across the country.

    That storm will reorganize this afternoon and evening over Alberta, and then move eastward overnight and tomorrow across Saskatchewan into Manitoba. The cold front attached to this storm is already swinging through the Northwest, and will progress across the northern Rockies into the northern Plains over the next 24 hours. There will be some cooling behind the front, no doubt! Washington, Oregon and Idaho were cool yesterday, and today will be as cool or even cooler. Tomorrow will be cooler across the northern Plains in the wake of the front, though the temperature departures in the northern Plains will not be all that great. Indeed, once to the eastern Dakotas and points downstream, it will remain above normal.

    Then a second system will move into the Northwest on Wednesday. Now, as storms go, this one will pale in comparison to the first one. Look at the upper-level trough, then the accompanying surface map:

    This will bring a bit of rain through the Northwest, but a far cry from what blasted the region yesterday.

    By the same token, its impacts downstream will be far, far greater. This is a feature that will be trackable downstream, first in the Rockies. Depending upon where the surface low reorganizes Thursday afternoon, there could be some rain in and around the flood-ravaged areas of Denver and Boulder. It's more certain farther north in parts of Wyoming and southern Montana. And it won't all be rain, either. In the higher elevations, it will change to snow. And then the colder air will plunge through the West and across the Rockies and out onto the Plains Thursday into Friday.

    As the storm itself deepens Thursday nighty and Friday and heads into the Midwest, it will pull more and more moisture into its circulation, resulting in more rain and some thunderstorms for the Midwest to end the week. By the same token, as the front barrels across the Plains, it will spark some strong to potentially severe thunderstorms Friday night into Saturday as it charges across the Mississippi Valley and into the Ohio and Tennessee valleys.

    The question will then become of how the front behaves downstream. There are some models that just bring it to the East Coast in weakened fashion with less and less moisture, while others try to pull moisture from the tropics across the Gulf of Mexico and send it to the frontal boundary, resulting in more widespread and potentially substantial rains across the central and eastern Gulf Coast, parts of the Deep South, and potentially parts of the East. That remains to be seen.

    The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com


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