Temps | Gusts | WU KORD KPWK

CLICK for this month's BIG night sky ...




Cardinal SAT


MOBILE DEVICE? Turn sideways. Weather conditions directly above are near Lakefront. Top tabs refer to O'Hare (official).

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.


Wednesday, December 27, 2023

SPC Dec 27, 2023 1300 UTC Day 1 Convective Outlook

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

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0644 AM CST Wed Dec 27 2023

Valid 271300Z - 281200Z


Severe thunderstorms are not forecast across the contiguous United
States through tonight.

In mid/upper levels, the dominant feature over the central/eastern
CONUS remains a large synoptic-scale cyclone, initially centered
over northwestern MO. Associated cyclonic flow extends from the
Four Corners region to the central/southern Appalachians, and from
the Upper Great Lakes to northern MX. Its 500-mb low is expected to
pivot southward then eastward over southern IL by the end of the
period. A broad warm conveyor lingers well east of the low, near
the central Atlantic Coast and northward over the central
Appalachians region. Weak, elevated buoyancy will decrease
northward, with 12Z soundings showing MUCAPE around 600 J/kg at MHX,
but less than 300 J/kg at RNK. This may support isolated, episodic
thunder in a band of embedded convection moving eastward to
northeastward over the area today into this evening.

The surface cold front is offshore from the southern Atlantic Coast,
though a frontal-wave low -- analyzed at 11Z just offshore from CHS
-- should move northeastward near the NC coastline through this
evening. However, favorable warm-sector buoyancy/shear for severe
is expected to stay over the Atlantic. A temporarily stalled
segment of the low-level frontal zone may undergo wave cyclogenesis
over the southeastern Gulf this evening and tonight, as a weak
southern-stream perturbation approaches from MX. Sufficient lift,
elevated instability and moisture should exist over Gulf waters to
support thunderstorms over the central/east-central Gulf today and
the east-central/southeastern Gulf tonight. Some of this activity
may reach portions of the FL Keys before 12Z tomorrow.

Farther west, moisture-channel imagery showed a synoptic-scale
cyclone over the northeast Pacific, centered near 43N137W. This
feature is expected to move northeastward and weaken today, while
remaining offshore. However, a basal shortwave trough should pivot
northeastward across the coastal Pacific Northwest. Related
DCVA/cooling aloft may provide sufficient destabilization, atop weak
low/middle-level moisture, to support thunder potential from
portions of northern CA up the coast of OR/WA.

..Edwards/Dean.. 12/27/2023

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)