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ACUS02 KWNS 121730
SPC AC 121729

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1129 AM CST Mon Nov 12 2018

Valid 131200Z - 141200Z


The risk for severe storms appears negligible (i.e., severe
probabilities less than 5 percent) across the U.S. Tuesday through
Tuesday night.

Models indicate that mid/upper ridging near the Pacific coast will
become less amplified during this period, as a vigorous short wave
impulse within the westerlies progresses inland, through its crest,
across the Canadian Rockies.  As this occurs, the downstream
westerlies appear likely to become more notably split, with
significant troughing within the northern branch forecast to
continue to evolve while shifting eastward across the eastern
Canadian provinces and adjacent portions of the Northeast. It
appears that at least one short wave impulse accelerating through
the base of this trough, preceded by a  perturbation emerging from
troughing within the southern branch, will provide support for
strong surface cyclogenesis along a frontal zone, from the northern
Mid Atlantic coast vicinity at 12Z Tuesday into the Canadian
Maritimes by late Tuesday night.  As this occurs, the trailing cold
front is expected to advance east of much of the remainder of the
south Atlantic coast, including at least northern portions of the
Florida Peninsula.

Models indicate that the leading edge of the significant cold
intrusion will also continue to advance southeastward through much
of the western and northern Gulf of Mexico, even as a mid/upper low
begins to evolve within initially sheared remnant southern branch
troughing across the southern Plains.

...Atlantic Seaboard...
Warm advection, aided by an intensifying southerly 850 mb jet
(50-70+ kt) near/east of the northern Mid Atlantic and New England
coast, may contribute to sufficient destabilization aloft to support
a northeastward spreading area of weak thunderstorm activity during
the day Tuesday.  Otherwise, it still appears that any potential for
more vigorous boundary-layer based thunderstorm activity along/ahead
of the cold front will be in the process of spreading east of the
North Carolina coast by the 12-14Z time frame Tuesday morning. 
While it may not be out of the question that some severe weather
potential could linger beyond 12Z, this risk seems confined to
portions of the Outer Banks vicinity and negligible enough to
maintain severe probabilities at less than 5 percent.

Additional isolated to widely scattered thunderstorm activity may
linger into the day Tuesday, along/above the southeastward advancing
surface front across parts of northern Florida and southeastern
Georgia, before diminishing in the presence of weakening large-scale

Other, isolated diurnal thunderstorm activity also appears possible
across the Florida Peninsula, despite the lingering influence of
mid/upper subtropical ridging.

Tornado:  <2%     - None
Wind:     <5%     - None
Hail:     <5%     - None

..Kerr.. 11/12/2018