Valid 011200Z – 021200Z
…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
PLAINS TO THE SOUTHERN GREAT LAKES…
…SUMMARY…
Isolated strong to severe storms are expected later today from parts
of the central Plains into the lower Great Lakes region.
…Discussion…
Dominant upper high will hold across the Mid-South early this week
ensuring a very moist trajectory extending around the periphery of
this feature from the southern Rockies – central Plains – southern
Great Lakes. One significant short-wave trough should top the ridge
over southern Canada then dig southeast toward northern New England
late in the period. In response to this feature, a surface low will
track southeast across QC allowing a surface front to surge south of
the international border later this evening. Prior to frontal
passage, a few strong/severe thunderstorms should develop over
southern ON then spread toward upstate NY with gusty winds being the
primary risk with this convection.
Farther west across the Plains into the southern Great Lakes, an
embedded short-wave trough will lift northeast across the southern
High Plains into central KS by early afternoon. This feature should
encourage a weak wave to form along a pronounced front over central
KS then track northeast into northwest IL by sunrise Wednesday.
Models are in general agreement that a narrow band of extensive
frontal convection will evolve ahead of the short wave, likely
developing fairly early in the afternoon. Wind profiles are forecast
to increase along this corridor such that shear will be more than
adequate for sustaining organized rotating updrafts. However,
considerable amount of convection may disrupt discrete cells, and
thunderstorm clusters and possible line segments may be more common.
CAMs support this scenario as well. Given the expected buoyancy
along the front, have opted to increase severe probs to account for
a higher threat for damaging winds with these high-PW thunderstorms.
..Darrow/Cook.. 10/01/2019
$$