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MESO: Severe potential MW
From
Weather Alert@454:1/105 to
All on Fri Mar 25 16:05:00 2022
ACUS11 KWNS 251918
SWOMCD
SPC MCD 251918
INZ000-ILZ000-WIZ000-IAZ000-252145-
Mesoscale Discussion 0337
NWS Storm Prediction Center Norman OK
0218 PM CDT Fri Mar 25 2022
Areas affected...Parts of northeastern Iowa through southern
Wisconsin and northern Illinois
Concerning...Severe potential...Watch unlikely
Valid 251918Z - 252145Z
Probability of Watch Issuance...5 percent
SUMMARY...Showers and isolated thunderstorms will overspread the
region through late afternoon, some accompanied by a mix of frozen precipitation, strong wind gusts approaching severe limits, and
occasional sharply reduced visibilities.
DISCUSSION...An intensifying cyclonic, northwesterly jet streak is
in the process of digging across and southeast of the Upper Midwest.
This includes speeds within its core increasing in excess of 90 kt
around 500 mb and 50 kt around 850 mb. Within the exit region of
this jet streak, strong lower/mid tropospheric cooling is ongoing
(including temps of -16 to -32C in the 700-500 mb layer),
contributing to pronounced steepening of low-level lapse rates.
This is currently becoming most prominent across parts of
northeastern Iowa and southwestern Wisconsin into northern Illinois,
aided by insolation, where deepening convective development is
underway.
Rapid Refresh forecast soundings suggest that the destabilizing
thermodynamic profiles may become supportive of convection reaching
15-20 thousand plus foot depths, and perhaps becoming capable of
occasionally producing lightning. Given the cold nature of these
profiles, including rather low freezing levels within a couple
thousand feet above ground level, the well-mixed sub-cloud boundary
layer probably will allow for a transition from rain to melting
frozen precipitation ranging from graupel to snow in the stronger showers/downdrafts. This may also enhance the downward mixing of
potentially damaging wind gusts to the surface, as activity develops southeastward through 22-00Z.
..Kerr.. 03/25/2022
ATTN...WFO...LOT...MKX...DVN...ARX...
LAT...LON 42019063 42979057 43268964 42408740 40558724 41118885
41548989 42019063
$$
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From
Weather Alert@454:1/105 to
All on Tue Mar 29 17:04:00 2022
ACUS11 KWNS 292039
SWOMCD
SPC MCD 292038
IAZ000-MOZ000-NEZ000-KSZ000-SDZ000-292245-
Mesoscale Discussion 0339
NWS Storm Prediction Center Norman OK
0338 PM CDT Tue Mar 29 2022
Areas affected...Mid-Missouri Valley
Concerning...Severe potential...Watch possible
Valid 292038Z - 292245Z
Probability of Watch Issuance...60 percent
SUMMARY...Elevated storms are expected to develop by late afternoon.
These storms will pose a threat for large hail and isolated damaging
winds. A watch is possible later this afternoon.
DISCUSSION...Water vapor imagery shows a shortwave trough moving
into western portions of Nebraska this afternoon. Signs of
large-scale ascent are increasing in south-central Nebraska with
cumulus deepening near the triple point. Observed soundings through
the day from OAX show mid-level lapse rates in excess of 8 C/km
along with an increasing warm nose around 800 mb. Despite very
limited surface moisture return ahead of the surface low, continued
elevated lift near the frontal zones is expected to promote storm
development by late this afternoon. With the low-level jet expected
to increase within the next 2-3 hours, some potential exists for
isolated development to occur. These initial storms would be capable
of small to marginally severe hail. Further mid-level cooling will
occur by early evening, leading to an increase in storm
coverage/intensity. Large hail will become a greater risk with time
as elevated buoyancy increases.
The threat for damaging winds will be limited by storms being rooted
above the surface. However, an isolated damaging gust is possible.
Wind gust potential will likely be maximized in northwest Missouri
into southeast Nebraska where low-level moisture will be greater and
storms may be nearly surface-based.
Trends will continue to be monitored for a potential watch later
this afternoon.
..Wendt/Hart.. 03/29/2022
ATTN...WFO...DMX...EAX...FSD...OAX...TOP...GID...LBF...
LAT...LON 40779474 40479483 40019539 39979636 40359735 41619809
42009831 42549818 43099753 43309689 43259640 41649520
41169491 40779474
$$
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From
Weather Alert@454:1/105 to
All on Mon Apr 25 16:12:00 2022
ACUS11 KWNS 251940
SWOMCD
SPC MCD 251939
NYZ000-PAZ000-OHZ000-252145-
Mesoscale Discussion 0563
NWS Storm Prediction Center Norman OK
0239 PM CDT Mon Apr 25 2022
Areas affected...Parts of northeastern Ohio...northwestern Pennsylvania...western New York state
Concerning...Severe potential...Watch unlikely
Valid 251939Z - 252145Z
Probability of Watch Issuance...20 percent
SUMMARY...Thunderstorm activity may intense further while developing northeastward in a narrow corridor near/southeast of Lake Erie
through 5-6 PM EDT. It still appears unlikely that a severe weather
watch will be needed, but a couple of these storms may be
accompanied by a few strong gusts approaching severe limits, and
perhaps some potential for a brief tornado.
DISCUSSION...A mid-level cyclonic vorticity center has been rapidly
migrating north-northeastward at 50+ kt, and is now passing north of
the Cleveland OH area. This has been accompanied by a sustained
small, elongated cluster of convection, including more recent
embedded thunderstorm development on its southern/southwestern
periphery, which appears likely to spread along and southwest of the
southern shores of Lake Erie into western New York state through
21-22Z.
Although, to this point, mixed-layer CAPE along this corridor
remains weak (on the order of 250-500 J/kg), low-level lapse rates
have become quite steep inland of the lake breeze in response to
insolation and mixing. And Rapid Refresh output suggest that
substantial modification of this environment could lead to
increasing CAPE during the next few hours. This may become
sufficient to support further thunderstorm development and
intensification.
The intersection of this activity with the lake breeze could provide
a focus for a supercell structure or two with some risk for a
tornado. Otherwise, locally strong surface gusts approaching severe
limits appears the primary potential severe hazard, in the presence
of deep-layer southwesterly ambient mean flow on the order of 40+
kt.
..Kerr/Guyer.. 04/25/2022
ATTN...WFO...BUF...CTP...PBZ...CLE...
LAT...LON 43447836 43077721 41797848 41307941 40008217 40638202
41678130 42227972 42687885 43447836
$$
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From
Weather Alert@454:1/105 to
All on Thu Jun 23 17:21:00 2022
ACUS11 KWNS 232057
SWOMCD
SPC MCD 232056
MNZ000-WIZ000-SDZ000-NDZ000-232330-
Mesoscale Discussion 1267
NWS Storm Prediction Center Norman OK
0356 PM CDT Thu Jun 23 2022
Areas affected...Far northeast SD into central MN
Concerning...Severe potential...Watch possible
Valid 232056Z - 232330Z
Probability of Watch Issuance...40 percent
SUMMARY...The area is being monitored for possible severe storm
development this afternoon and evening. While uncertain, a watch
could eventually be needed for parts of northeast SD into central
MN.
DISCUSSION...Visible satellite imagery shows a modest uptick in
boundary-layer cumulus along a weak surface trough extending across
parts of central MN into northeast SD. While boundary-layer flow is
veered south of the surface boundary, weak low-level warm advection
is supporting a modest increase in low-level confluence. Earlier 12Z
soundings over the northern Plains showed a plume of steep midlevel
lapse rates which has now overspread parts of MN per RAP
mesoanalysis. The steep midlevel lapse rates atop a
moist/deeply-mixed boundary layer are contributing to
moderate/strong surface-based buoyancy -- strongest over northeast
SD into western MN where surface temperatures have climbed into the middle/upper 90s beneath the core of the steeper lapse rates.
As diurnal destabilization continues amid the modest low-level
confluence, isolated to widely scattered storm development may occur
over parts of northeast SD into central MN this afternoon/evening.
While deep-layer flow/shear is modest (25-35 kt of effective shear),
the favorable buoyancy and at least some deep-layer shear could
support isolated large hail initially. Eventually, damaging winds
could become an increasing concern with any convective clustering
amid the steep low/mid-level lapse rates. Overall confidence in
storm development and maintenance is limited, though trends are
being monitored and a watch could eventually be needed.
..Weinman/Grams.. 06/23/2022
ATTN...WFO...DLH...MPX...FGF...ABR...
LAT...LON 45909717 46649588 47299380 47309313 47029274 46489254
45809276 45389329 44879655 45059710 45519732 45909717
= = =
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