Severe Storm Outlook Narrative (AC)
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ACUS02 KWNS 231714
SPC AC 231713

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1213 PM CDT Fri Mar 23 2018

Valid 241200Z - 251200Z


Thunderstorms are possible Saturday primarily across the Ohio Valley
and along the Pacific Northwest Coast during the day. Other
thunderstorms might occur late Saturday night over a portion of the
the southern Plains and early Sunday morning across the northern

...Mid-Mississippi/Ohio/Tennessee Valley Regions...
A deamplifying shortwave trough will traverse the region from
northwest to southeast throughout the day.  Lift associated with
this feature, along with isentropic lift along/north of a warm front
extending from central Missouri through central Tennessee, will
promote widespread shower/thunderstorm development throughout the
day.  This activity should spread southeastward toward the
Appalachians overnight.  A risk for small hail will exist on the
western extent of this activity (eastern Missouri into Illinois)
early in the period due to steep (7-8C/km) mid-level lapse rates in
that area, although organized/widespread severe weather is not

...Northwestern U.S....
Very cold temperatures aloft (-30 to -38C at 500mb) associated with
a longwave trough over the region will result in very steep lapse
rates and thermodynamic profiles favoring lightning throughout the
forecast period.  This risk will be highest along coastal areas from
northern California northward to southwestern Washington State.
This lightning risk may be more diurnally driven across the northern
Rockies, but will be encouraged by lift associated with a shortwave
traversing the region during the afternoon.  An isolated strike or
two cannot be completely ruled out in eastern Oregon and vicinity
very late in the period.

...Southern/Central Plains...
A cold front is expected to stall very near the Red River Valley
during the day and remain stationary through the overnight hours.
Although not widespread, models suggest potential for isolated
thunderstorms to develop along and north of this front - likely in
response to increasing isentropic ascent and a subtle mid-level
shortwave trough approaching the region toward 09-12Z Sunday.

...Portions of the Northern High Plains...
Mid-level height falls are expected to overspread the region in
response to an approaching shortwave ejecting from eastern Montana
into south-central Canadian provinces.  Cooling temperatures aloft
will support modest mid-level destabilization and the potential for
a few lightning strikes from elevated convection migrating
northeastward across the region during the evening and overnight
hours (00Z-12Z Sunday).

..Cook.. 03/23/2018

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