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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.


Thursday, June 6, 2024

SPC Jun 6, 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
0714 AM CDT Thu Jun 06 2024

Valid 061300Z - 071200Z


Damaging gusts of 60-70 mph will be possible this afternoon/evening
across western Oklahoma and the eastern Texas Panhandle. Isolated
wind damage will be possible this afternoon from eastern New York
into the Carolinas, and isolated wind damage/hail may also occur
across the central/east central Florida peninsula.

...TX Panhandle/western OK this afternoon/evening...
In the wake of a midlevel low over the upper Great Lakes, a weak
surface cold front will drift southward from KS into northern OK and
the TX/OK Panhandles by later this afternoon/evening. Weak lee
cyclogenesis across eastern NM will induce southerly low-level flow
and northward moisture advection across TX/OK to the south of the
front. Strong surface heating and the increase in low-level
moisture will contribute to moderate buoyancy by mid-late afternoon
(MLCAPE >1500 J/kg), in an environment of steep low-level lapse
rates/deep mixing. Low-level convergence/ascent along the front
should focus thunderstorm development by mid-late afternoon from
northwest OK into the TX Panhandle, and storms will subsequently
spread southward through the evening. Moderate buoyancy, inverted-V
profiles and northwesterly effective bulk shear of 35-40 kt will
favor a mix of multicell clusters and high-based supercells capable
of producing severe outflow gusts (mainly 60-70 mph) and isolated
large hail (1-1.5 inch diameter).

...East central FL this afternoon...
The Atlantic coast sea breeze will likely be favored this afternoon
for thunderstorm development, within a weak background westerly flow
regime. Strong surface heating across the central peninsula,
boundary-layer dewpoints in the 70s, and midlevel lapse rates near 7
C/km will result in MLCAPE near 3000 J/kg with minimal convective
inhibition. Seasonally cool midlevel temperatures (-8 to -10 C at
500 mb) and the large buoyancy will support some threat for isolated
large hail (1-1.5 inches in diameter) where vertical shear is
slightly enhanced by the sea breeze. The large buoyancy will also
result in substantial water-loaded downdrafts with the potential for
isolated wind damage (55-65 mph gusts) in an environment with steep
low-level lapse rates and DCAPE > 1000 J/kg.

...NY into the Carolinas this afternoon/evening...
A pronounced midlevel trough will progress eastward from the Great
Lakes to NY/PA by this evening, and it will be accompanied by a
surface cold front and pre-frontal trough in the lee of the higher
terrain. Midlevel lapse rates in the warm sector will not be steep,
but surface heating in cloud breaks and boundary-layer dewpoints of
65-70 F will support MLCAPE of 1000-1500 J/kg by early-mid
afternoon, when storm development is expected along the surface
boundaries. There will be some increase in midlevel flow over the
surface warm sector this afternoon (30+ kt flow near 500 mb), which
will favor primarily multicell clusters and line segments capable of
producing occasional wind damage (50-60 mph gusts).

Somewhat greater storm coverage is expected in the vicinity of
eastern NY where forcing for ascent will be more focused, with more
scattered storms farther south into the Carolinas. Despite weaker
deep-layer vertical shear with southward extent toward the
Carolinas, modest enhancement of flow in the 700-500 mb layer (30+
kt) and steep low-level lapse rates will support isolated downbursts
with wind damage. Portions of this area will be re-evaluated in
later outlooks for higher wind probabilities, primarily for
sufficient cloud breaks and resultant destabilization.

..Thompson/Grams.. 06/06/2024

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)