SPC 1300Z Day 1 Outlook

Day 1 Outlook Image

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0758 AM CDT Sat Oct 10 2020

Valid 101300Z - 111200Z


A few tornadoes are possible today into this evening across the Deep
South including parts of Alabama, Georgia, and Florida Panhandle.
Severe thunderstorms are also expected across parts of northern New
York and northern New England.

...Deep South including Alabama/Georgia/Florida Panhandle...
Tropical Cyclone Delta, which is centered over far west-central
Mississippi around sunrise, will continue northeastward. Although
the remnant circulation/low will tend to weaken, low-level winds on
its eastern periphery will remain strong (40-55 kt), with the
strongest core of south-southwesterly winds in the lowest 2-3 km AGL
expected to transition east-northeastward across Alabama/Florida
today, and toward Georgia and the nearby southern Appalachians by

Transient low-topped (including an absence of lightning flashes)
low-level mesocyclones have been noted through the early morning
hours within a zone of confluence across southwest Alabama and the
western Florida Panhandle. Potentially aided by cloud breaks and the
periphery of the eastward-advancing mid-level dry slot, a diurnal
destabilization trend this morning into afternoon may modestly boost
low-level parcel accelerations and updraft intensity (albeit still
low-topped). Diurnal destabilization aside, a general northeastward
flux of low-level moisture will coincide with the entrance region of
the low-level jet, which should allow for a net east-northeastward
transition of the tornado threat today across additional parts of
Alabama toward western Georgia.

...Northeast/New England...
An upper-level trough centered near the border vicinity of northern
Ontario/northern Quebec early today will steadily amplify and
progress eastward today toward northern New England. While surface
dewpoints are only in the 40s F early today, a steady influx of
modest moisture is expected into the region ahead of an
east/southeastward-advancing cold front. Given the kinematic
scenario, low-level moisture/buoyancy should be adequate for the
development of stronger convection this afternoon. This should
initially occur over northern portions of New York into northern
Vermont/New Hampshire, while additional low-topped thunderstorms may
develop across/move out of eastern Quebec into Maine a bit later
this afternoon through early/mid evening. Very strong deep-layer
west-southwesterly winds will support fast eastward-moving bands of
storms capable of wind damage and possibly some line-embedded
tornado risk.

...Western Washington...
A locally severe storm, including the potential for convectively
enhanced wind gusts, cannot be entirely ruled out early today in
general association with an eastward-moving/inland-spreading
shortwave trough and associated front. However, very limited
buoyancy, as sampled by the 12Z observed KUIL/Quillayute sounding,
suggests that any such severe potential should remain limited.

..Guyer/Goss.. 10/10/2020

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