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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.


Tuesday, May 28, 2024

SPC May 28, 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
1259 AM CDT Tue May 28 2024

Valid 281200Z - 291200Z


Widespread strong to severe storms are expected over much of Texas
later today, with potential for significant damaging wind and areas
of very large hail.

...Southern Plains...
Rich low-level moisture and strong to extreme instability (MLCAPE of
3000-5000 J/kg) will be in place at the start of the forecast period
across much of Texas, to the south of a surface front draped from
northwest into east TX, and to the east of a dryline across
southwest TX. Strong elevated buoyancy will extend north of the
boundary into parts of OK.

Elevated convection will likely be ongoing this morning, mainly
near/north of the front. Large hail and locally gusty winds will be
possible with these elevated storms. Evolution of the morning
convection will be crucial in determining the magnitude and location
of the greatest severe threat later in the day. It is possible that
morning storms will grow upscale and move southeastward along the
instability gradient, which would push the outflow-reinforced front
southward through the day. Any upscale growth during the morning
could result in an MCS posing a risk of severe wind gusts
potentially into parts of northeast TX and northwest LA.

If outflow does not become too expansive during the morning, then
intense storm development will be possible this afternoon in the
vicinity of the dryline across west TX. While midlevel flow will not
be very strong, substantial veering with height will support
sufficient effective shear for supercell development. Very large
hail (greater than 2 inches in diameter) and localized severe gusts
could accompany any supercell. Some tornado threat could also
evolve, especially near the dryline/front intersection, as well as
with any supercell that survives into the richer low-level moisture
east of the dryline. A southeastward-moving MCS could evolve out of
initial supercell development, which would pose a threat of very
damaging wind gusts (potentially in excess of 80 mph) if the
initially very favorable thermodynamic environment is not disrupted
by early-day outflow.

If convective outflow surges across much of TX relatively early in
the day, then potential for a longer-lived and organized MCS will be
reduced. However, even in this scenario, a few intense
cells/clusters capable of very large hail and significant severe
gusts will still be possible. At this time, the area of greatest
confidence in higher-end severe potential lies roughly from the TX
Big Country region into parts of central/north TX. The southeastward
and westward extent of the greater threat will be determined in part
by the evolution of the outflow-reinforced front through the day.

...Eastern OR into northern ID into western MT...
A strong mid/upper-level shortwave trough will move eastward across
the Pacific Northwest later today into tonight. While moisture will
be limited ahead of this system, steep low/midlevel lapse rates will
support modest destabilization, and scattered thunderstorm
development will be possible this afternoon into the evening.
Stronger flow aloft will be displaced westward of storm development,
but deep-layer shear may still be sufficient to support a few
stronger cells/clusters capable of isolated severe gusts and perhaps
some hail.

...Southern WI into Northern IL/IN...
A few strong storms will be possible this afternoon into the early
evening from southern WI into parts of northern IL/IN. While
low-level moisture and deep-layer shear will generally be modest,
cold temperatures aloft will support MLCAPE rising into the 500-1000
J/kg range. A couple stronger multicells could become capable of
producing hail. Strong wind gusts could also accompany the strongest
storms, especially where greater pre-storm heating can occur through
the day.

..Dean/Moore.. 05/28/2024

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)