Day 1 Severe Weather Outlook

Valid 011630Z – 021200Z


Isolated strong to severe storms are expected from late afternoon
into the mid evening from parts of the Great Plains into the Mid
Missouri Valley and Great Lakes.

…WI to MI…
A large upper ridge is centered over the central/southern MS Valley
today, with relatively strong midlevel winds extending from west TX
into IA/WI and eastward into MI/NY/VT. This axis is where the
surface baroclinic zone lies, and will be the focus for organized
thunderstorm development today and tonight.

Once cluster of storms is currently over WI and Lower MI. Heating
is occurring along the southern flank of this activity, where
sufficient destabilization will result in surface-based storms by
mid-afternoon. Forecast soundings show sufficient westerly flow
aloft for a risk of a few damaging wind gusts in the strongest
cells. Please refer to MCD #2046 for more details.

…TX to IA…
A large but weakening MCS over the TX Panhandle will likely track
into northwest OK and central KS this afternoon, where MLCAPE values
around 1000 J/kg will develop. Midlevel lapse rates are forecast to
be weak, limiting updraft intensity and hail threat. However,
strong winds aloft and sufficient vertical shear will pose a risk of
bowing/rotating cells capable of damaging winds and a tornado or two
from central KS into parts of northwest MO and IA.

Strong heating is occurring today over parts of southern Ontario,
where sufficient CAPE will result in scattered afternoon
thunderstorms. These storms will track eastward into parts of
northern NY and VT. Forecast soundings show strong winds aloft and
perhaps enough thermodynamic support for a few strong/severe storms
capable of damaging wind gusts. However, broken cloud cover and
dewpoints only in the 50s to lower 60s in much of the region will
likely limit the extent of the threat today.

..Hart/Kerr.. 10/01/2019


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