Day 1 Severe Weather Outlook

Valid 030100Z – 031200Z


Severe thunderstorms capable of producing mainly damaging winds will
continue across parts of the Upper Midwest through early Tuesday
morning, with the most likely corridor from west-central into
southern Minnesota and west-central Wisconsin. A low tornado risk
will also continue through the overnight hours along parts of the
Florida east coast in association with Hurricane Dorian.

…Northern Plains/Upper Midwest…
A small but well organized bow echo that produced multiple measured
severe wind gusts across central/eastern ND earlier this afternoon
will continue southeastward into parts of the Upper Midwest this
evening and overnight. Greater surface-based instability will likely
remain displaced to the south of this line of storms. Even so, a
40-50 kt south-southwesterly low-level jet and strengthening winds
in the 700-500 mb layer associated with a shortwave trough moving
eastward over the northern Plains will likely support continued
storm organization and intensity tonight. Given the linear storm
mode, severe winds will likely remain the primary threat, with the
greatest damaging wind threat across parts of southern/central MN
into west-central WI along an instability gradient. Isolated
significant severe wind gusts of 65 kt may occur in this corridor
given the strength of the low and mid-level winds. A tornado or two
will also remain possible, particularly if the southern flank of the
line can ingest more buoyant low-level air near/just north of a
surface warm front.

Isolated strong to severe thunderstorms that developed earlier today
across parts of the Northeast and Mid-Atlantic ahead of a surface
cold front should continue to weaken this evening with the loss of
daytime heating. However, occasional strong/gusty downdraft winds
associated with these storms may remain possible in the short term
(next 1-2 hours) as 35-40 kt of mid-level flow and similar values of
effective bulk shear remain over this region.

…Florida Atlantic Coast…
Hurricane Dorian is forecast by the National Hurricane Center to
move slowly west-northwestward through early Tuesday morning. Dorian
will likely remain far enough offshore to limit the overall tornado
threat. Still, low-level hodographs should gain some additional
length/curvature overnight as winds strengthen along the east coast
of the FL Peninsula. Any low-topped cells that can develop in outer
convective rainbands might pose a risk for a brief tornado.

..Gleason.. 09/03/2019


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