SPC 1200Z Day 1 Outlook

Day 1 Outlook Image

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1232 AM CDT Mon Oct 19 2020

Valid 191200Z - 201200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not expected today.

...AR to Western KY...

Neutral-weak large-scale height rises are forecast across much of
the country east of the Rockies during the day1 period as broad
cyclonic flow persists across the northern two-thirds of the CONUS.
In the absence of appreciable large-scale forcing for ascent, a
veered LLJ should be the primary forcing mechanism for potential
convective development along/north of a slow-moving cold front.
Early this morning, the boundary was draped from northeast
TX-central AR-southeast MO-southern IN. A corridor of higher PW
(1.5+ inch) extends along the frontal zone and this moisture plume
should move little through the period. Scattered convection has been
noted along the cool side of the front Sunday evening but lightning
is notably sparse at 06z. Forecast soundings along/north of the
front suggest the most buoyant parcels will be near 850-900mb where
MUCAPE should be on the order of 500-900 J/kg. With mid-level lapse
rates not expected to be particularly steep, updraft strength with
this activity should be limited along with the prospect for severe
hail. For these reasons, have opted to lower severe hail probs to
less than 5 percent.

..Darrow/Lyons.. 10/19/2020

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