Day 1 Severe Weather Outlook

Valid 011300Z – 021200Z


Severe thunderstorms are unlikely today in the contiguous U.S.

With blocky upper-air patterns persisting across the northeastern
Pacific and west-central North Atlantic, longwave troughing will be
maintained over the central/east-central CONUS, reinforced by a
series of shortwave to synoptic-scale perturbations. A compact
mid/upper cyclone — evident in moisture-channel imagery over
southwestern QC, will eject northeastward across Labrador and weaken
through the period. Meanwhile, a positively tilted synoptic trough
— initially located from northeastern MB to central CO — will move
southeastward to the upper Great Lakes, mid Mississippi Valley,
Ozarks, and north-central/northeast TX. Several low-amplitude
shortwaves will pivot around this trough through the period.

At the surface, the 11Z analysis showed a cold front over Atlantic
waters offshore from Cape Cod, southwestward to the central FL
Atlantic coast, near an XMR-VNC line, then over the south-central
Gulf. This front is expected to decelerate as it moves
southeastward down the FL Peninsula through the period, reaching the
Lake Okeechobee area by this evening.

Isolated to widely scattered thunderstorms are possible along and
especially south of the front this afternoon, mainly near sea-breeze
and outflow boundaries. A deep troposphere and large low-level
theta-e will offset modest lapse rates and small stable layers above
the boundary layer enough to yield only weakly inhibited deep
buoyancy, with peak MLCAPE values around 1500-2000 J/kg. Weak,
erratic flow through the troposphere and a related lack of vertical
shear will limit storm organization.

..Edwards.. 11/01/2019


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