Severe Storm Outlook Narrative (AC)
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ACUS03 KWNS 240651
SPC AC 240650

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0150 AM CDT Tue Oct 24 2017

Valid 261200Z - 271200Z


The risk for severe thunderstorms appears negligible across the
U.S., Thursday through Thursday night.

Mid/upper flow appears likely to remain amplified across the eastern
Pacific into North America through this period.  Within this regime,
a significant mid/upper high center may develop near the Pacific
Northwest coast, within larger-scale ridging building as far north
as the Canadian Yukon and Northwest Territories.  Downstream,
cyclonic flow is forecast to continue to sharpen near/ east the
length of the U.S. Rockies through the Mississippi Valley.
The initial Eastern large-scale trough is expected to continue to
lose amplitude while accelerating northeast of the Atlantic
Seaboard.  However, it now appears that a vigorous remnant short
wave impulse could support significant surface cyclogenesis along a
frontal zone across parts of eastern Maine into eastern
Quebec/western New Foundland and Labrador.

This latter development may be accompanied by some risk for
generally weak thunderstorm activity across parts of Maine.
Potential for thermodynamic profiles to become supportive of an
appreciable severe weather risk still seems low at this time.

Ahead of another cold front advancing across and southeast of the
southern Plains and Ozark Plateau by late Thursday night, some
northwest Gulf of Mexico boundary layer moistening and inland
advection appears possible.  However, it currently appears unlikely
to contribute to sufficient destabilization to support an
appreciable risk for thunderstorm activity.

..Kerr.. 10/24/2017

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