SPC 1300Z Day 1 Outlook

Day 1 Outlook Image

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0729 AM CDT Wed Oct 14 2020

Valid 141300Z - 151200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A SMALL
PORTION OF THE UPPER MISSISSIPPI VALLEY AREA...

...SUMMARY...
A strong/severe wind gust or two may occur this afternoon over
portions of the upper Mississippi Valley region.

...Synopsis...
Gradual amplification of the upper flow field over the U.S. is
expected today, as short-wave troughing initially crossing the
northern Intermountain Region digs southeastward into the central
states.  By the end of the period, an expanding/broad belt of
cyclonic flow -- centered over the central third of the U.S. -- is
expected to cover nearly the entire country.

At the surface, a southeastward-surging cold front is expected to
evolve, in conjunction with the digging upper system.  During the
afternoon, the front should extend from a low over the upper
Mississippi Valley area southwestward into the central Plains.  By
the end of the period, as the low shifts northeastward into eastern
Canada, the cold front will likely have advanced to a position
extending from the lower Great Lakes to Texas.

...Upper Mississippi Valley area...
As the surface cold front and parent upper system advance eastward
across the upper Mississippi Valley area this afternoon, modest
pre-frontal moistening/destabilization is expected -- with CAPE
generally on the order of 150 to 350 J/kg anticipated.  This -- in
conjunction with strong ascent near the surface front -- should be
sufficient to support a couple of stronger low-topped updrafts. 
Aided by moderately strong/quasi-unidirectional westerly flow
increasing with height through the lower troposphere, a
stronger/damaging gust or two cannot be ruled out as convection
shifts quickly eastward.  The greatest risk is expected during the
late afternoon, near peak heating, with convection then weakening
with the onset of diurnal stabilization.

..Goss.. 10/14/2020

Read more
There’s more click here.

Comments are closed.