Jan 27 2015
...A clipper system will evolve into a coastal storm bringing snow from
the Ohio Valley to the northeastern states...
...Well above normal temperatures expected over the central U.S...
...Wet weather is in the forecast for the Desert Southwest...
The amplified pattern across the nation will continue which features a
broad upper trough extending over the eastern half of the U.S. Meanwhile,
a rex block is expected across the West which indicates a ridge is bounded
to the south by a closed upper low.
The deep upper trough stretching from the Great Plains eastward to the
Eastern Seaboard will allow a series of disturbances to dig through the
Ohio/Tennessee Valleys and eventually into the Mid-Atlantic. The initial
system which spread wintry precipitation to sections of the Northeast is
departing into the Canadian Maritimes. While snow has ended across New
England, gusty winds continue given the strength of the surface cyclone.
In its wake, a very brief lull in the pattern is noted with the next
system currently advancing through the Middle Mississippi Valley. This
clipper system will initially be rather moisture deprived which is the
typical nature of these systems. This should spread an area of 2 to 6
inches of snow to the Ohio Valley. As the upper trough amplifies across
the lower Tennessee Valley on Sunday evening, a coastal low is forecast to
develop which will significantly increase the moisture available to the
storm. This will ultimately raise the snowfall totals across the
Mid-Atlantic along with the southern half of New England. Currently, the
WPC winter weather desk is expecting 4 to 8 inches over the Maryland
Panhandle into southern Pennsylvania while a swath of 6 to 12 inches will
be possible from New Jersey up to eastern Massachusetts. All amounts are
through Tuesday morning with snow continuing to fall across the Upper
Mid-Atlantic and New England afterward. In addition to the heavy snow
prospects, a tightening pressure gradient will lead to gusty winds which
may bring blizzard conditions to sections of the affected area.
Over the Central U.S., expect well above normal temperatures to prevail
across Northern Rockies along with the Great Plains region. This is in
response to a persistent downslope flow which will significant warm the
surface temperatures east of the higher terrain. The current forecast
anomalies suggest readings of 20 to 30 degrees above normal which would
translate to highs nearing 70 across the Central High Plains on Monday.
Elsewhere in the nation, a secondary clipper system is expected to cross
the Upper Great Lakes spreading light snowfall accumulations on Monday.
Looking to the southwestern states, the earlier mentioned closed low will
lift northward from the subtropical East Pacific. Enhanced moisture
combined with strong vertical lift will spread a hefty batch of rainfall
to the Desert Southwest on Monday and Tuesday. Widespread rainfall amounts
of 0.25 to 0.50 inches are likely with heavier amounts in the local
terrain.
Rubin-Oster
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php
NOAA/ National Weather Service
National Centers for Environmental Prediction
Weather Prediction Center
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