Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
527 PM EDT Thu Oct 30 2014
Valid 00Z Fri Oct 31 2014 - 00Z Sun Nov 02 2014
...Heavy snow possible for portions of the southern and central
Appalachians Friday night and Saturday...
...Well below-average temperatures expected for most of the central and
...Strong Pacific storm system to bring rain and snow to much of the West
and Intermountain West...
Both the western and eastern U.S. will see significant weather during the
short range forecast period as the upper-level flow across the nation
becomes highly amplified. A vigorous upper-level disturbance will dive
southward across the Upper Great Lakes tonight and into the Ohio valley on
Friday. At the surface, one frontal system will cross the Great Lakes and
Ohio Valley while another develops and deepens off the North Carolina
coast. A polar high pressure will usher a much colder airmass into the
central and eastern U.S. behind the western of the two aforementioned
systems, with temperatures 10 to 20 degrees below average in some areas.
Rain and snow will be possible across the Great Lakes on Friday as the
system crosses the area, with snow for the Ohio valley. The more
significant event will begin Friday night into early Saturday, however, as
the energy from the two systems begins to combine, and colder air changes
rain over to snow across much of the eastern Ohio Valley, and central and
southern Appalachians. Upslope flow across the Appalachians with
northwesterly flow may enhance snowfall, and heavy snow is possible.
Additionally, rain and snow are possible on Saturday across portions of
northern interior New England.
Another vigorous low-pressure system will move onshore in the West
tonight. Widespread precipitation is expected along and in the wake of the
surface front. While precipitation will begin as rain at all but the
highest elevations of the West, snow levels will gradually lower as the
front moves inland and the upper-level trough crosses overhead, so by
Saturday snow will become much more commonplace across the Intermountain
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php