Severe Storm Outlook Narrative (AC)
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ACUS48 KWNS 190801
SPC AC 190759

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0259 AM CDT Mon Mar 19 2018

Valid 221200Z - 271200Z

An expansive area of cyclonic flow aloft will remain across eastern
North America on D4 with dual upper lows near New England. At this
time, a surface ridge will extend from the upper MS Valley into the
Gulf of Mexico, resulting in stable conditions. Meanwhile, an upper
ridge will be located over the Plains.

On D5, a shortwave trough will move from the southwestern states
into the Plains, with the upper ridge shifting toward the MS Valley.
While low pressure will form over the Plains in response to this
wave, moisture return will initially be meager and will only support
elevated storms in a warm advection regime Friday night across parts
of the Midwest. Some thunderstorm activity is possible across the
lower MS Valley on D6, but severe weather is not expected as the
shortwave trough minors out across the OH Valley.

For D7-D8, models suggest another upper trough will be poised to
affect the central part of the U.S., and moisture will likely be
more abundant across the southern Plains into the lower MS Valley.
Predictability is currently low given model differences, and, even a
"perfect prog" approach does not appear to yield more than a
marginal severe threat.

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