Day 1 Severe Weather Outlook

Valid 101200Z – 111200Z

…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
KANSAS INTO NORTHEAST OKLAHOMA AND NORTHWEST ARKASAS AND PARTS OF
THE SOUTHERN SAN JOAQUIN VALLEY…

…SUMMARY…
There is a marginal risk for severe thunderstorms from central
Kansas into northeast Oklahoma and northwest Arkansas late this
evening into the overnight. A couple of strong thunderstorms are
possible within the southern San Joaquin Valley this afternoon.

…Synopsis…
Quasi-zonal flow aloft with embedded shortwave troughs will exist
across the eastern two-thirds of the CONUS. A shortwave disturbance
early Tuesday morning over the Midwest will move eastward into the
Northeast. An attendant surface low will deepen and cold front will
push into the Appalachians/Mid-Atlantic. Later in the period, an
impulse over the northern Rockies will progress southeastward into
the central Plains/mid-Mississippi Valley. A weak surface cyclone
will develop in eastern Colorado, moving southeastward into Oklahoma
by the end of the period.

…Kansas/Oklahoma into the Ozarks…
Steep mid-level lapse rates will advect into the region within the
northwest flow regime aloft. As the surface low deepens, strong
elevated thunderstorms are likely to develop around 05Z along the
weak advancing cold front as a modest increase in the low-level jet
occurs during the evening and overnight. Large hail will the primary
threat with initial activity, supported by 500-1500 J/kg MUCAPE and
adequate deep-layer shear for storm organization. With time, this
activity is expected to grow upscale and the primary threat
transitioning to an isolated wind hazard.

…Southern San Joaquin Valley…
As a closed upper-low approaches southern California, strong ascent
and 50-60 kts of mid-level flow will overlap a warming/moistening
boundary layer during the afternoon. A few stronger cells may
produce isolated strong wind gusts. Cold temperatures aloft may
support small hail, though relatively weak buoyancy should limit
severe hail potential. Other isolated, strong storms are possible in
parts of southern coastal Calfiornia, but considerable uncertainty
remains precluding low probabilities.

…Mid-Atlantic…
Scant buoyancy of 50-100 J/kg MUCAPE may develop during the late
afternoon ahead of the advancing cold front. Forecast soundings show
very modest inverted-V profiles that would support some potential
risk for strong/damaging wind gusts, given the strong low-level
flow. However, the weak, low-topped nature of the convection along
with the surface low displaced to the northeast creates enough
uncertainty in storm coverage/intensity that no severe probabilities
will be introduced this outlook.

..Wendt/Smith.. 03/10/2020

$$

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