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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.

ARLINGTON HEIGHTS WEATHER

Monday, March 18, 2024

SPC Mar 18, 2024 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0740 AM CDT Mon Mar 18 2024

Valid 181300Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
ACROSS CENTRAL FL AND MUCH OF THE FL ATLANTIC COAST...

...SUMMARY...
Isolated large hail and wind damage is possible this afternoon
across central Florida and along much of the Florida Atlantic coast.

...FL this afternoon...
A northern stream shortwave trough will dig from the mid MS Valley
this morning to the southern Appalachians this evening and off the
Atlantic coast by early Tuesday. An associated stalled surface
front across north FL this morning will begin to accelerate
southeastward across the peninsula this evening through early
Tuesday. The more pronounced midlevel height falls and forcing for
ascent will pass north of FL, leaving shallow ascent along the front
and/or differential heating boundaries (from convection moving
inland from the northeast Gulf of Mexico this morning) to focus
thunderstorm development. Forecast soundings suggest that moderate
buoyancy (MLCAPE near 1500 J/kg), steep low-level lapse rates and 50
kt midlevel flow with relatively straight hodographs could support a
supercell capable of producing isolated large hail (1-1.75 inches in
diameter) and damaging gusts near 60 mph. The severe threat will
peak by early-mid afternoon and then diminish into this evening.

...AZ/southern CA through this evening...
As part of a Rex block, a closed low over AZ will drift westward
today as an embedded speed max pivots from northern AZ toward
southern CA. Low-level moisture will remain modest, but cool
midlevel temperatures and daytime heating will contribute to at
least weak buoyancy (SBCAPE of 250-750 J/kg). A few clusters of
storms will form in the main band of ascent over the rim this
afternoon, while other storms are expected to spread southwestward
off the higher terrain toward the southern CA coast. The threat for
severe storms will remain quite low, but the strongest storms could
produce gusty outflow winds and small hail.

..Thompson/Dean.. 03/18/2024


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/T4FB5G

SPC Mar 18, 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
1237 AM CDT Mon Mar 18 2024

Valid 181200Z - 191200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE FLORIDA PENINSULA...

...SUMMARY...
Isolated severe thunderstorms are possible over most of the Florida
Peninsula through the late afternoon before the severe risk
diminishes by early evening.

...FL Peninsula...
A large-scale mid-level trough over the Great Lakes/MS Valley will
pivot east through the Eastern Seaboard during the period. The
primary belt of stronger ascent/flow associated with the upper
trough will move across the southern Appalachian states and be
displaced from the FL Peninsula. In the low levels, a cold front
will gradually push south during the day and reach the FL Straits by
late evening. However, before frontal passage, a moist airmass
characterized by mainly 60s dewpoints across the Peninsula, will
become weakly to moderately unstable by late morning into the
afternoon (500-2000 J/kg MLCAPE). Strong mid to high-level westerly
flow will aid in some storm organization and perhaps yield a couple
of transient supercells. Models currently indicate isolated to
widely scattered thunderstorms developing during day. Some of the
stronger storms may be capable of a localized threat for wind damage
and/or hail risk. The stronger thunderstorms will likely weaken by
early evening with the severe threat diminishing.

..Smith/Supinie.. 03/18/2024


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/T4DQ9K

Sunday, March 17, 2024

SPC Mar 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
1122 AM CDT Sun Mar 17 2024

Valid 171630Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MOUTH
OF THE MISSISSIPPI TO THE FLORIDA BIG BEND...

...SUMMARY...
Local/isolated risk for gusty/damaging winds remains possible today
from southeastern Louisiana to the Florida Panhandle/Big Bend area.

...Gulf Coastal area from southeastern Louisiana to the Florida Big
Bend...
A well-defined MCS with embedded MCV is moving eastward across the
southeastern Louisiana vicinity late this morning, along the
west-to-east synoptic cold front lying roughly across the Gulf Coast
region.

West of this convective complex, weak quasi-geostrophic ascent
across Texas -- within a zone of modest low-level warm advection
beneath minor mid-level disturbances moving through fast
west-southwesterly flow aloft southeast of the Desert Southwest
upper low -- will support occasional deep convection. However,
aside from a couple of sporadic stronger storms and possibly
brief/marginally severe hail/wind risk locally, risk appears too low
to require inclusion of probabilities in the current outlook.

East of the MCS, limited severe risk remains apparent across coastal
areas, though the strongest storms should remain over the northern
Gulf. Still, gusty/locally damaging winds may occur, warranting
continuation of 5% wind probability as far east as the Florida Big
Bend region through tonight.

..Goss/Weinman.. 03/17/2024


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/T4CSmq

SPC Mar 17, 2024 1300 UTC Day 1 Convective Outlook

LIVE MAP (ABOVE) ... SPC 1300Z Day 1 Outlook


Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0745 AM CDT Sun Mar 17 2024

Valid 171300Z - 181200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TODAY FROM
SOUTHERN LA TO THE FL PANHANDLE...

...SUMMARY...
Isolated severe thunderstorms are possible today from southern
Louisiana to the Florida Panhandle.

...Gulf coast through this evening...
A Rex block will be maintained over the western CONUS, while a
northern stream shortwave trough digs south-southeastward over the
upper Midwest. A reinforcing cool surge will accompany the
amplifying northern stream, while a southern stream will persist
over the Gulf coast, east of the closed low over AZ.

A developing MCS near the northwest Gulf coast is expected to move
generally eastward today near the northern Gulf coast, roughly along
a quasi-stationary front across the extreme northern Gulf of Mexico.
As a result, much of the convection will remain a little offshore,
with inland threats for damaging wind/hail limited to the northern
comma head of the MCV, and more cellular (slightly elevated)
convection in the warm advection wing east of the MCV across
southern LA (near the north edge of the richer low-level moisture
and moderate buoyancy). The weakening MCS is expected to reach the
FL Panhandle late this afternoon and the isolated severe threat will
diminish by this evening.

Farther west, the potential for additional strong-severe storm
development is quite uncertain into TX. Forcing for ascent will be
nebulous at best in the wake of the MCV, and the remaining warm
sector will be displaced southward this evening into tonight by a
reinforcing cool surge. For these reasons, have opted to remove the
Marginal risk area from TX.

..Thompson/Dean.. 03/17/2024


Read more CHECK UPDATE ZOOM GRAPHIC


http://dlvr.it/T4BtlL
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)