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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.


Saturday, April 6, 2024

SPC Apr 6, 2024 0600 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1255 AM CDT Sat Apr 06 2024

Valid 061200Z - 071200Z


Severe storms will be possible across parts of the central Plains
this afternoon and early evening. Severe wind gusts, isolated hail,
and a couple tornadoes will all be possible.

...Central Plains vicinity...
A deep upper-level trough will take on an increasingly negative tilt
as it ejects into the central Plains later today. A strong
mid/upper-level jet (with 80-100 kt at 500 mb) will move through the
base of the trough and overspread the warm sector of a deepening
cyclone centered over the central High Plains. A cold front will
move eastward across KS/OK through the day, with an occluded portion
of the front expected to extend northwestward from north-central KS
into western/central NE.

While the synoptic pattern favors severe-thunderstorm potential
across parts of the central Plains, the threat will be mitigated to
some extent by limited low-level moisture. Dewpoints are likely to
remain in the 40s F across most of NE, and only reach the low 50s F
into parts of central KS. However, diurnal heating beneath cold
temperatures aloft and steep midlevel lapse rates will support
MLCAPE increasing to near 500 J/kg. Strong ascent attendant to the
ejecting upper-level trough will aid in storm development by early
afternoon near the occluded front across central/western NE, with
development possible into northern/central KS by mid/late afternoon.
Strengthening midlevel flow will support sufficient effective shear
for storm organization. A few low-topped supercells are expected,
though there may be a tendency toward more linear storm modes with
time as strong forcing overspreads the region.

Marginal instability will tend to limit the hail threat to some
extent, though any sustained supercell could produce isolated hail
in the 1-1.5 inch diameter range. While the tornado threat may tend
to be limited by sparse low-level moisture, sufficient low-level
shear/SRH could support at least a brief tornado threat with any
stronger sustained supercell, especially in closer proximity to the
surface low. A corridor of greater tornado probabilities may
eventually be needed if observational trends support more favorable
low-level moisture, and/or if confidence increases in potential for
longer-lived supercells. Otherwise, severe wind gusts in the 60-75
mph range may be the most likely hazard, as low-level lapse rates
steepen, deep-layer flow strengthens, and convection takes on a more
linear mode with time.

While the primary severe threat is expected from southwest/central
NE into central/eastern KS, some threat could spread into eastern NE
before convection weakens by late evening. A strong storm or two
could also develop by early evening across southeast KS and eastern
OK, in response to gradually increasing moisture along/ahead of the
cold front.

..Dean/Moore.. 04/06/2024

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