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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.


Thursday, January 11, 2024

SPC Jan 11, 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
1158 PM CST Wed Jan 10 2024

Valid 111200Z - 121200Z


Severe thunderstorms, associated with tornadoes, wind damage and
isolated large hail, are likely to develop across parts of the
Ark-La-Tex this evening into the overnight. A severe threat is also
expected to develop further south across parts of east Texas and

An impressive upper-level system will translate quickly eastward
through the Desert Southwest today, reaching the southern Plains
this evening. Within the base of the trough, a 100 to 120 knot
mid-level jet will move through west Texas this evening, as the nose
of the jet overspreads the Ark-La-Tex. Ahead of the system, moisture
will return northward across east Texas and Louisiana, with the nose
of the moist sector reaching southern Arkansas by early evening. In
response, a pocket of instability is forecast to develop across
southeast Oklahoma, southwest Arkansas and northeast Texas, where
convective initiation is expected during the mid evening.
Thunderstorms are likely to rapidly increase in coverage during the
late evening. Most hi-resolution models develop a line of strong to
severe storms and move the line slowly eastward across southwest
Arkansas and far northeast Texas during the early overnight period.
As lift and shear increase due to the approach the mid-level jet,
conditions are expected to become favorable for severe storms.

Model forecast soundings across the Ark-La-Tex by 06Z have surface
dewpoints near 60 F as far north as the Louisiana and Arkansas state
line. Even so, MLCAPE should reach the 500 to 1000 J/kg range at the
northern edge of the moist sector by late evening. Very strong lift
associated with the exit region of the mid-level jet combined with
low LCL heights and strong low-level shear should be favorable for
supercells embedded in the line, and with the more discrete cells
that develop ahead of the line. Some forecast soundings suggest that
700-500 mb lapse rates will approach 8 C/km across the northern part
of the warm sector. Although the large-hail threat should remain
isolated, the steep mid-level lapse rates should be sufficient for a
significant-hail threat. Hailstones of greater than 2 inches in
diameter will be possible a few hours after cells initiation, as the
storms mature. In addition, 0-3 km storm-relative helicity is
forecast to peak near 400 m2/s2 in and just north of the Shreveport
vicinity. This is also expected to support a tornado threat with the
more intense supercells. Any supercell that can persist and become
dominant may be able to produce a significant tornado or two. A
wind-damage threat will also likely develop along the line of
storms, with the greatest potential located across Ark-La-Tex, where
an Enhanced risk has been introduced.

...East Texas/Louisiana...
Further south into east Texas and Louisiana, storm coverage is
expected to be more isolated from the late evening into the
overnight period. In this area, to the south of the mid-level jet
axis, instability is not expected to be as strong. Also, lift may
not be quite as concentrated. For this reason, supercell development
is expected to remain more isolated. Any cell that can become
organized and sustained could produce isolated large hail, wind
damage and a tornado or two. The severe threat should more isolated
with southward extent, with only a marginal severe threat expected
near in the coastal sections of southeast Texas and southern

..Broyles/Lyons.. 01/11/2024

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)