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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.


Monday, April 8, 2024

SPC Apr 8, 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
1250 AM CDT Mon Apr 08 2024

Valid 081200Z - 091200Z


Multiple rounds of severe thunderstorms should develop from early
afternoon today through Tuesday morning across a large portion of
the southern Plains into the Mississippi Delta region. Large to very
large hail is the main threat (potentially up to 4 inches),
especially over northwest Texas, though a few tornadoes and severe
wind gusts will also be possible.

A positively-tilted mid-level trough will amplify as it moves across
the Southwest and northern Mexico today. Ahead of this trough, a
broad region of moderate mid-level southwesterly flow will
overspread the southern Plains and into the lower-Mississippi
Valley. A weak surface cyclone will develop in West Texas and deepen
through the period. As this occurs, the remnant front across
southeast Texas early this morning will start to lift north as a
warm front through the day. Mid-60s dewpoints are expected as far
north as the Red River by 00Z. A cold front moving south through the
central Plains this morning will meet this warm front near the Red
River by late afternoon/early evening and become mostly stationary
and mark the northward extent of significant destabilization and
thus severe risk.

...Northwest Texas into north-central Texas...
Storms are expected to rapidly form on the northwestern periphery of
moisture return in a region of pressure falls across northwest Texas
this afternoon. 40 to 45 knots of effective shear should support
supercell organization. These storms will initially be high-based
with limited moisture with large to very large hail as the primary
threat. Low-level flow is forecast to be mostly weak, but there will
be strong low-level veering which may be sufficient for some
low-level updraft organization. Storms will move into better
low-level moisture late in the afternoon and into the evening, which
may increase the potential for a tornado or two.

...East Texas into the ArkLaTex...
Moderate to strong instability is expected to develop across east
Texas and into western Louisiana this afternoon as upper 60s to near
70s dewpoints advect northward. Despite a rare total solar eclipse
across this region, its impact on the overall severe weather threat
will likely remain minimal. Only moderate warming will be sufficient
to erode inhibition across the region with the strengthening
low-level jet and isentropic ascent as the primary focus for storm
development later in the afternoon. Therefore, most guidance shows
storms developing between 20Z and 22Z as the low-level jet
strengthens, even the RAP/HRRR which account for eclipse-related
radiation effects.

Strong instability and shear is expected which will support
supercells capable of large to very large hail. However, there are
some concerns about storm interference and updraft longevity.
Initially, a warm nose around 700mb is evident on NAM/RAP forecast
soundings which may limit more robust updraft development. This warm
nose is forecast to erode by 23/00Z. However, by that time,
widespread shower/thunderstorm development may be underway which
could be a limiting factor to updraft longevity and a greater
tornado/large hail threat.

Some guidance suggests a MCS may develop out of the
northwest/north-central Texas convection and move through northeast
Texas during the overnight hours. This solution will greatly depend
on the evolution of earlier convection and position of the
convectively enhanced warm front by late evening.

...Texas Hill Country overnight...
Monday night, height falls will overspread much of Texas with a
secondary low-level jet max strengthening into portions of central
Texas. After 06Z, a very favorable environment will be present with
NAM/RAP forecast soundings showing 2500 to 3000 J/kg MUCAPE and over
60 knots of effective shear. Therefore, there is a conditional
threat for strong supercells with a threat for large to very large
hail if isentropic ascent is sufficient for storm development into
central Texas.

...West Texas early Tuesday...
The dryline is expected to retreat into West Texas overnight with
strong instability building back to near Midland early Tuesday
morning. As forcing overspreads this region Tuesday morning, storms
are expected to develop in a very unstable and strongly sheared
environment. Therefore, supercells are possible with large to very
large hail as the primary threat.

..Bentley.. 04/08/2024

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)