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Archives for the SPC Convective Outlook are updated daily (approximately) with a live map at the beginning of each article. Follow the link at the end of the article to check for current updates on the NOAA/NWS Storm Prediction Center website. Also, see Archives for Chicago's hourly weather data on CARDINAL NEWS Magazine.


Wednesday, April 17, 2024

SPC Apr 17, 2024 1630 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1630Z Day 1 Outlook

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1144 AM CDT Wed Apr 17 2024

Valid 171630Z - 181200Z


Scattered thunderstorms capable of producing damaging winds, large
hail, and a few tornadoes should develop across parts of the Ohio
Valley and Lower Great Lakes this afternoon. Thunderstorms with
mainly a large hail threat may occur tonight over parts of the
central Plains.

Satellite imagery continues to show a negatively tilted upper trough
extending from the Upper Midwest into the OH Valley. Surface low
associated with this trough is currently over northeast WI. An
occluded front extends southwestward from this low to a triple point
in the southern Lake Michigan vicinity. From this triple point, a
warm front extends east-southeastward across southern Lower MI into
northeast OH and a cold front extends south-southwestward across
western IN and southern IL. Strong to severe thunderstorms are
anticipated along and ahead of the cold front as it moves across the
OH Valley and Lower MI today and tonight. This cold front then
becomes stationary as it becomes more east-west orientated over AR
before transitioning to a warm front OK.

...Lower Michigan into the Ohio/Tennessee Valleys...
As mentioned in recently issued MCDs #469 and #470, the showers and
isolated thunderstorms currently ongoing along and ahead of the cold
front are expected to gradually intensify as the downstream air mass
diurnally destabilizes. Stronger forcing for ascent is anticipated
across Lower MI, which will favor quicker upscale growth into one or
more bowing segments. As such, primary severe risk over Lower MI is
expected to be damaging gusts from 45 to 65 mph.

Farther south, less forcing for ascent and generally modest buoyancy
should favor less storm coverage than areas farther north, with a
more cellular storm mode anticipated as well. This region will be
displaced north of the stronger upper-level flow, but the enhanced
mid-level flow in place should still be sufficient for updraft
organization and the potential for a few supercells. Primary risk
with these storms will be hail around 1" and damaging gusts from 45
to 65 mph, but low-level flow is expected to be strong enough to
support some tornado potential as well.

Continued development along and ahead of the front could lead foster
a transition to a more linear mode with eastern extent this evening.
Damaging gusts and line-embedded tornadoes will still be possible.

...Eastern KS into the Mid/Lower MO Valley...
An upper-level trough will move eastward across the north-central
CONUS tonight. Isolated thunderstorms are possible later this
evening in central NE. Expectation is for these storms to be
elevated, but some hail is possible.

A 40-45 kt southerly low-level jet will develop this evening across
parts of the southern/central Plains in response to the approaching
trough. Thunderstorms should eventually initiate near the northern
edge of the low-level jet late this evening from central KS into far
southeast NE. Ample buoyancy, and strong shear in the cloud-bearing
layer should support some threat for large hail with this mainly
elevated convection. If convection can grow upscale into a small
bowing cluster, then isolated damaging winds may also occur.

Across the Mid-Atlantic, filtered daytime heating will contribute to
a well-mixed boundary layer and steep low-level lapse rates,
resulting in modest buoyancy this afternoon. A few thunderstorms may
move into the region off the higher terrain, with occasionally
damaging gusts possible. Given the limited instability, the overall
severe wind threat will likely remain isolated.

...Texas Hill Country into Northwest TX...
Isolated thunderstorms may develop late this afternoon and early
evening across parts of south-central into central TX along the
dryline. If any convection can be sustained, it could produce severe
winds and hail, but the threat currently appears too uncertain to
introduce any severe probabilities.

..Mosier/Bentley.. 04/17/2024

SUNRISE AND SUNSET TIMES IN UTC (if you're not logged in to Google)
CHICAGO UTC-6 during CST (Central Standard Time, e.g., winter)
CHICAGO UTC-5 during CDT (Daylight Savings Time, e.g., summer)