9/28 Long Term
Forecast updated 2:25pm EST - 28 Sep 2011
The cut off low pressure that has been persisting over the Midwest is expected to finally begin
moving off to the ENE and taking with it most of the precipitation. Following behind the low and
it's associated cold front, high pressure will begin to move in at the surface. This will bring with it
much cooler air. The combination of colder air flowing south over the warmer water of Lake Michigan
will bring the chance of lake effect precipitation, especially in northern Indiana.
Today's 12Z GFS run at 12Z Saturday (mean sea level pressure, 850mb-500mb thinkness and 6hr precip)
By Monday morning, a ridge begins to build in across the Midwest and South with the beginning of warm
air advecting into the region due in part the return flow associated with a eastward moving high pressure at
Todays 12Z GFS run at 12Z on Monday
With warmer temperatures in place across much of the Midwest by next Wednesday, upper-level flow
becomes much more zonal. The next major system begins to show up by 12Z Wednesday over the
Northwest accoring to today's 12 GFS run. The jetstream at 250mb depicts very high winds speeds
within the jet streak around the developing trough out west.
today's long-range forecast graphic was produced by Ryan Meiszberg