LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1046 PM CST Mon Jan 20 2025
Valid 211200Z - 221200Z
...NO THUNDERSTORM AREAS FORECAST...
...SUMMARY...
The risk for thunderstorms appears negligible across the U.S. today
through tonight.
...Discussion...
Ridging to the north of the blocking mid-level high centered over
the mid-latitude eastern Pacific is rebuilding, as an initially
suppressing short wave perturbation progresses inland across British
Columbia. The latter feature is forecast to dig through the
northern U.S. Rockies and adjacent Great Plains by 12Z Wednesday,
reinforcing large-scale troughing now encompassing much of central
and eastern North America. As this occurs, a pair of initially
digging downstream short wave perturbations will be forced
east-northeastward, into and through strong, confluent flow between
a prominent mid-level ridge centered over the subtropical western
Atlantic and a broad cyclonic circulation centered over the far
northeastern Canadian provinces.
Although down slope flow may contribute to moderating temperatures
across the northern and central Great Plains, seasonably cold air
associated with surface ridging entrenched across much of the
southern Great Plains through Atlantic Seaboard will generally be
maintained. It appears that the shallow leading edge of this cold
air mass will remain south and east of the Florida Peninsula and
Keys, with little in the way of surface frontal wave development
across the west central through southeastern Gulf of Mexico due to
lack of mid/upper support.
...Northwestern Gulf coast...
In the presence of steepening mid-level lapse rates associated with
differential thermal advection, it still appears that elevated
moisture return will contribute to weak destabilization (rooted in
the 800-700 mb layer) as far northwest as upper Texas/Louisiana
coastal areas by 12-15Z this morning. This probably will provide
support for a period of increasing convective development, with
thermodynamic profiles possibly become conducive to at least some
lightning production before diminishing by early afternoon. There
remains substantive spread concerning this potential, however, and
thunderstorm probabilities will be maintained at less than 10
percent, based on objective calibrated guidance from both the NCEP
SREF and HREF.
..Kerr.. 01/21/2025
Read more CHECK UPDATE ZOOM GRAPHIC
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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.
CONVECTIVE | TORNADO | WIND | HAIL
O'Hare International Airport KORD
(Arlington Heights South)
Chicago Executive Airport KPWK
(Arlington Heights North)
Tuesday, January 21, 2025
SPC Jan 21, 2025 0600 UTC Day 1 Convective Outlook
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)
CHICAGO UTC-6 during CST (Central Standard Time, e.g., winter)
CHICAGO UTC-5 during CDT (Daylight Savings Time, e.g., summer)