ACUS11 KWNS 021243
SWOMCD
SPC MCD 021242=20
ILZ000-021445-

Mesoscale Discussion 1630
NWS Storm Prediction Center Norman OK
0742 AM CDT Tue Aug 02 2022

Areas affected...west central/central Illinois

Concerning...Severe potential...Watch unlikely=20

Valid 021242Z - 021445Z

Probability of Watch Issuance...20 percent

SUMMARY...A cluster of thunderstorms may organize further and pose
increasing potential to produce strong to severe gusts in corridor
across and southeast of Peoria, into the Decatur vicinity, before
probably weakening after 10-11 AM CDT. It is not clear that this
will require a severe weather watch, but trends will be monitored.

DISCUSSION...Weak low-level frontogenetic forcing and warm advection
have contributed to large-scale ascent supporting persistent
thunderstorm development, including a couple of evolving clusters,
in a zone near/east of the middle Mississippi into lower Ohio
Valleys. This is occurring in the presence of weakly sheared, 10-20
kt northwesterly deep-layer mean flow, but seasonably high moisture
content concentrated along/above (to the cool side of) the front
appears to be contributing to large CAPE on the order of 2000-3000
J/kg.

Cloud tops have cooled and peak lightning flash rates have increased
with the trailing cluster of storms now approaching the Peoria, IL
area, and a small lower/mid tropospheric cyclonic circulation may be
evolving within the intensifying convection along the leading edge
of developing surface cold pool. As the cold pool continues south-southeastward, observational data and objective analysis
suggest that a south-southwesterly inflow of unstable air may
maintain vigorous thunderstorm development into mid morning. As
long as this continues, it is possible that the evolving MCV may
become better defined as it migrates along the frontal zone,
accompanied by strengthening rear inflow and strong surface gusts.

As activity propagates south of the Interstate 70 into 64 corridors
of southern Illinois, it probably will begin to process more stable
air impacted by preceding convection and seems likely to diminish.

..Kerr/Thompson.. 08/02/2022

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!4M10V0A8lBvF_rR9fuiG5gCngBv7gDWrMQmpyYbW-u_DuI9cUTpq3Oot1lrcZQpbYqzzPGaE8= V67vPJebcr0Tl1L6OY$ for graphic product...

ATTN...WFO...ILX...LSX...DVN...

LAT...LON 40638968 40458945 39768903 39378932 39589000 40089040
40419064 40449052 40449004 40638968=20


=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.14-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)

ACUS11 KWNS 191944
SWOMCD
SPC MCD 191943=20
NEZ000-KSZ000-OKZ000-COZ000-NMZ000-192145-

Mesoscale Discussion 1630
NWS Storm Prediction Center Norman OK
0243 PM CDT Wed Jul 19 2023

Areas affected...South-central/southwest NE...northwestern
KS...eastern CO...and northeastern NM

Concerning...Severe potential...Watch possible=20

Valid 191943Z - 192145Z

Probability of Watch Issuance...60 percent

SUMMARY...The severe-risk will increase during the next few hours.
Large hail and damaging winds are the primary concerns. A watch may
eventually be needed for parts of the area.

DISCUSSION...Latest surface observations indicate a surface
boundary/wind shift extending roughly from the Palmer Divide
northeastward into southwestern NE -- where cumulus continues to
deepen and isolated convective initiation is ongoing. Additional
convective development is noted along the higher terrain from CO
southward into NM. Through this corridor, continued diurnal heating
of a moist outflow-modified air mass (middle 50s to lower/middle 60s
dewpoints) beneath steep midlevel lapse rates will yield moderate
surface-based instability. Farther northeast in south-central NE, an
additional recovering outflow boundary (evident in visible satellite
loops) may also provide a focus for thunderstorm development --
aided by pockets of heating through cloud breaks.

With a belt of 30-40 kt midlevel westerlies (per regional VWP) atop
sheltered east-northeasterly low-level flow, long/mostly straight
hodographs (40-50 kt of effective shear) will favor splitting
supercells and organized clusters capable of large hail and severe
winds. There is uncertainty on overall convective evolution and
coverage of storms given lingering inhibition associated with
earlier outflow and generally weak large-scale ascent, though a
watch may eventually be needed for parts of the area.

..Weinman/Hart.. 07/19/2023

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_5lsguEEsAfb-Vl5WnDo3Sul4TQfv6Fz-VWr16p5WC3yENqJQFE5ew1pP2ZGw7EWihQ-01Xl6= lwTWn2n0KI0q5Gs84I$ for graphic product...

ATTN...WFO...GID...LBF...DDC...GLD...AMA...PUB...BOU...ABQ...

LAT...LON 38770105 38940060 39150020 39400004 39739994 40749990
41159993 41360005 41480032 41530079 41470103 41170127
40890154 40330227 39940294 39430367 39100407 38710428
38220438 37150439 36700433 36490382 36620331 36930292
37250261 37680233 38260201 38570159 38770105=20


=3D =3D =3D
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.

--- SBBSecho 3.14-Linux
* Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105)