SPC MD 1205

MD 1205 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF SOUTHERN AR.

MD 1205 Image


Mesoscale Discussion 1205
NWS Storm Prediction Center Norman OK
0950 AM CDT Mon Jul 30 2018

Areas affected...portions of southern AR.

Concerning...Severe potential...Watch unlikely 

Valid 301450Z - 301645Z

Probability of Watch Issuance...5 percent

SUMMARY...The remains of an overnight convective complex, having
entered southwestern AR, may produce strong/isolated severe gusts
through the remaining forenoon hours.  The severe threat presently
appears too marginal in magnitude and limited in coverage for a
watch, but will be monitored.

DISCUSSION...Some re-intensification trend has been noted with the
convective complex over the past 30-60 minutes -- both in IR
cloud-top cooling and radar-composite imagery.  Surface mesoanalysis
shows a weak, quasistationary frontal zone in preconvective
environment over southern AR, representing the trailing extension of
a cold front extending southwestward from a frontal-wave low over
western KY.  A corridor of relatively maximized convergence, in
otherwise weak boundary-layer flow, may help to focus convective
coverage/strength over the next few hours as the residual cold pool
of the MCS continues forward-propagating along and behind its
outflow boundary.  The favorably moist air mass over southern AR
should continue to destabilize somewhat before thicker anvil cloud
cover moves overhead, offsetting modest midlevel lapse rates enough
to boost MLCAPE to near 1500 J/kg, based on modifications to both
model soundings and an interpolation of 12Z SHV/LZK RAOBs. 
Low-level and deep shear each will remain weak.  The bulk of
reflectivity may remain several miles behind the outflow boundary,
except for a warm-advection wing not directly related to the cold
pool and posing minimal severe threat on its own.  As such,
organized severe potential appears limited, but isolated damaging
gusts still are possible.

..Edwards/Grams.. 07/30/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...JAN...LZK...SHV...

LAT...LON   33199388 33589405 34319395 34439290 34329196 33259192
            33129286 33199388 

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SPC MD 1199

MD 1199 CONCERNING TORNADO WATCH 322… FOR SOUTHEASTERN WYOMING…EASTERN COLORADO…WESTERN NEBRASKA…AND FAR NORTHWESTERN KANSAS

MD 1199 Image


Mesoscale Discussion 1199
NWS Storm Prediction Center Norman OK
0623 PM CDT Sun Jul 29 2018

Areas affected...southeastern Wyoming...eastern Colorado...western
Nebraska...and far northwestern Kansas

Concerning...Tornado Watch 322...

Valid 292323Z - 300030Z

The severe weather threat for Tornado Watch 322 continues.

SUMMARY...The severe threat continues across WW 322.

DISCUSSION...Southeastward-moving thunderstorms continue to migrate
across WW 322 at this time.  Favorable shear/buoyancy profiles have
supported occasional tornado and very large hail reports -
especially with a cluster of supercells migrating across
northeastern Colorado.  Over the past hour or so, one dominant
high-precipitation supercell has evolved over Morgan and Washington
Counties and an expansive cold pool has spread northwest from this
storm across much of Weld County and vicinity.  This may signal the
beginning of upscale growth advertised by the past several runs of
high-res models.  

Upstream (in southeastern Wyoming), cellular storms may continue to
pose a threat for very large hail and a tornado or two given
favorable shear profiles and storm mode.  Eventually, ongoing storms
will move top the remnant cold pool across northeastern Colorado,
which may lessen the overall tornado threat but still support large
hail in the strongest cores.

Farther south, convection near/west of Pueblo, CO has exhibited
brief supercellular characteristics and necessitated a spatial
expansion of the WW.  Hail, damaging wind gusts, and tornadoes may
evolve from any dominant storm that can materialize in this region.

..Cook.. 07/29/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...LBF...DDC...UNR...GLD...PUB...BOU...CYS...RIW...

LAT...LON   43420632 43540561 43510433 43030318 41970228 40860186
            39760147 38570158 38260164 38040218 37650308 37570419
            37830505 38250538 38850533 39700513 40470542 41020617
            41940652 42850659 43420632 

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SPC MD 1179

MD 1179 CONCERNING TORNADO WATCH 315… FOR SOUTHEAST WYOMING…SOUTHWEST NEBRASKA…EASTERN COLORADO AND WESTERN KANSAS

MD 1179 Image


Mesoscale Discussion 1179
NWS Storm Prediction Center Norman OK
0623 PM CDT Fri Jul 27 2018

Areas affected...southeast Wyoming...southwest Nebraska...eastern
Colorado and western Kansas

Concerning...Tornado Watch 315...

Valid 272323Z - 280100Z

The severe weather threat for Tornado Watch 315 continues.

SUMMARY...Threat for a couple tornadoes, isolated large hail, and
damaging wind will persist across WW 315 next couple hours. A more
substantial severe/damaging wind threat may evolve over the
southeastern portion of WW 315 and into severe thunderstorm watch
317 from east central Colorado through western KS into mid-evening.

DISCUSSION...Early this evening, numerous storms are developing
along a what appears to be a convectively reinforced boundary from
north central KS into northeast CO. Mostly discrete supercell
structures persist over KS. However, there has been a tendency for
storms to congeal into a small cluster across northeast CO. The
atmosphere across southeast CO into western KS remains moderately
unstable with 1500-2000 J/kg MLCAPE and is weakly capped. This along
with a strengthening southerly nocturnal low-level jet will continue
to support development along the consolidated outflows, and tendency
should be for storms to grow upscale into a southward-advancing MCS.
While large hail, and a couple tornadoes remain possible in the
short term, greatest severe threat should transition to damaging
wind.

Farther north across the remainder of tornado watch 315 from
southeast WY into western NE and far northeast CO, much of the
boundary layer has been stabilized by convective outflow. However,
latest objective analysis indicates the presence of moderate MUCAPE
for parcels lifted from above the surface layer. Therefore storms
over southeast WY will remain capable of producing mainly large hail
as they move southeast and become elevated over top of the stable
layer next couple hours.

..Dial.. 07/27/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...DDC...GLD...PUB...

LAT...LON   37689925 37590105 38480275 39290275 39160040 38829932
            37689925 

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SPC MD 1166

MD 1166 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF SOUTH-CENTRAL MT

MD 1166 Image


Mesoscale Discussion 1166
NWS Storm Prediction Center Norman OK
0210 PM CDT Thu Jul 26 2018

Areas affected...Portions of south-central MT

Concerning...Severe potential...Watch unlikely 

Valid 261910Z - 262145Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorms capable of severe hail and severe wind gusts
will evolve through the area this afternoon but are expected to be
isolated enough to preclude a Watch.

DISCUSSION...A subtle perturbation in relatively moist mid-to-upper
level flow rounding the top of the western ridge, sufficient
mid-level lapse rates, and surface heating within low 50s dewpoints
has contributed to isolated thunderstorms early this afternoon. 
Continued heating should contribute to further destabilization ahead
of the storms moving off the Big Snowy Mountains, as well over the
higher elevations to the west and northwest of there.  

An additional storm or two is expected to emerge from the decaying
storms currently over Musselshell county as a corridor of increasing
MLCAPE and steepening low-level lapse rates becomes established over
the area.  Effective shear in the 35-45 kt range should allow for
supercell structures and severe hail/wind potential as these storms
respond to the increasing CAPE.  Additional thunderstorms should
develop off the Little and Big Belt Mountains to the north and west
into the Glacier National Park area, where a similar environment
will also support a severe hail/wind threat.  However, given the
weak large-scale forcing for ascent and somewhat limited
instability, the coverage of storms/severe weather is expected to
remain low enough to preclude a Watch, but the area will be
monitored throughout the afternoon for signs of a more widespread
severe threat.

..Coniglio/Hart.. 07/26/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...BYZ...GGW...TFX...MSO...

LAT...LON   45130893 45241010 45841194 46961336 47621375 48251393
            48791351 48771306 48201179 47500999 47040881 46460782
            45870748 45480754 45010773 45120883 45130893 

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SPC MD 1156

MD 1156 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PORTIONS OF WESTERN KANSAS…EASTERN COLORADO…AND FAR SOUTHERN NEBRASKA

MD 1156 Image


Mesoscale Discussion 1156
NWS Storm Prediction Center Norman OK
0156 PM CDT Wed Jul 25 2018

Areas affected...Portions of Western Kansas...Eastern Colorado...and
Far Southern Nebraska

Concerning...Severe potential...Watch possible 

Valid 251856Z - 252130Z

Probability of Watch Issuance...60 percent

SUMMARY...Storms are expecting to develop this afternoon with some
of the storms likely becoming severe. Hail/wind are the main
threats.

DISCUSSION...A cluster of thunderstorms has been moving southeast
throughout the morning over Nebraska and into northern Kansas. Just
to the west of this storm cluster, storms are expected to develop
along/near frontal boundaries stretching across northern Kansas and
into eastern Colorado. Strong daytime heating (surface temperatures
90+ F) should help focus convective initiation near these boundaries
and storms will form in a convectively conducive environment
characterized by MLCAPE of 1500-3000 J/kg and effective bulk shear
of 30-50 knots. This should promote multicellular convection with
rotating storms capable of producing severe hail/wind this afternoon
and into the evening. These storms could organize upscale into a
QLCS this evening and track south-southeast across far eastern
Colorado and western/central Kansas. A watch is possible given the
eventual likelihood of severe storms.

..Nauslar/Hart.. 07/25/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...TOP...ICT...GID...LBF...DDC...GLD...PUB...BOU...

LAT...LON   40249977 40430035 40380068 40040145 39800203 39680261
            39500295 39160304 38770291 38300263 37640188 37580136
            37560078 37509972 37689911 38079838 38209814 38389776
            38659767 38869775 39149801 39539847 40249977 

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SPC MD 1110

MD 1110 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR SOUTHERN KANSAS INTO FAR NORTHEAST OKLAHOMA…FAR SOUTHWEST MISSOURI…AND FAR NORTHWEST ARKANSAS

MD 1110 Image


Mesoscale Discussion 1110
NWS Storm Prediction Center Norman OK
0926 PM CDT Fri Jul 20 2018

Areas affected...Southern Kansas into far northeast Oklahoma...far
southwest Missouri...and far northwest Arkansas

Concerning...Severe potential...Watch possible 

Valid 210226Z - 210400Z

Probability of Watch Issuance...40 percent

SUMMARY...Several strong to severe storms are possible early
tonight. Large hail will be the primary threat.

DISCUSSION...The last hour of GOES-16 10.35u satellite imagery shows
expanding mid-level clouds across much of southern Kansas in an area
of moist isentropic ascent. Expect several elevated storms to form
in this area over the next hour or two. With MUCAPE of 3000 to 4000
J/kg and 50 to 60 knots of effective shear per DDC 00Z sounding and
latest RAP mesoanalysis, expect these storms to be supercellular.
Very steep mid-level lapse rates (8.5 C/km per 00Z DDC sounding)
will support a primary threat of large hail. Any storms which form
in this area will likely only last for a few hours as 700mb flow
veers and isentropic lift weakens. The duration of these storms may
limit the need for a watch, but if enough storms form, a watch may
be necessary.

..Bentley/Goss.. 07/21/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...SGF...TSA...TOP...ICT...DDC...

LAT...LON   38070094 38150024 38229894 38189796 38119652 38029547
            37839491 37269397 36859386 36239374 36099402 36109452
            36709541 37069678 37089775 37099870 37129961 37340042
            37770098 38070094 

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SPC MD 1087

MD 1087 CONCERNING SEVERE THUNDERSTORM WATCH 283…284… FOR PORTIONS OF NORTHEAST KANSAS INTO WESTERN MISSOURI

MD 1087 Image


Mesoscale Discussion 1087
NWS Storm Prediction Center Norman OK
0243 PM CDT Thu Jul 19 2018

Areas affected...Portions of northeast Kansas into western Missouri

Concerning...Severe Thunderstorm Watch 283...284...

Valid 191943Z - 192115Z

The severe weather threat for Severe Thunderstorm Watch 283, 284
continues.

SUMMARY...A corridor of damaging winds will remain possible near
I-70 from Topeka eastward this afternoon. These storms are expected
to reach western portions of the KC metro around 4pm.

DISCUSSION...A cluster of severe thunderstorms, capable of damaging
winds at times approaching 75+ mph, is progressing east around 45
mph along the I-70 corridor this afternoon. Ahead of this cluster,
visible satellite illustrates towering cumulus, suggesting a
sufficiently unstable downstream environment. This is supported by
the 18Z TOP sounding, which sampled steep low/mid-level lapse rates
and ample northwesterly 700-500mb flow. Furthermore, dry air beneath
500mb will enhance evaporative cooling within downdrafts already
augmented by the aforementioned strong flow. All of these factors
will likely maintain a threat of severe wind gusts (some possibly
75+ mph) reaching the KC metro (especially western portions) around
4pm.

..Picca.. 07/19/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...EAX...TOP...ICT...

LAT...LON   39559684 39629493 39439459 38969444 38359454 38289513
            38539656 38899710 39239712 39559684 

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SPC MD 1083

MD 1083 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PORTIONS OF NORTHERN/EASTERN KANSAS

MD 1083 Image


Mesoscale Discussion 1083
NWS Storm Prediction Center Norman OK
1137 AM CDT Thu Jul 19 2018

Areas affected...Portions of northern/eastern Kansas

Concerning...Severe potential...Watch possible 

Valid 191637Z - 191830Z

Probability of Watch Issuance...60 percent

SUMMARY...Developing thunderstorms over northern Kansas may
gradually spread east/southeastward through this afternoon. Some of
these storms will be capable of damaging winds and large hail. A
watch could be needed within the next 1-2 hours.

DISCUSSION...A cluster of thunderstorms has formed within a field of
ACCAS over north-central Kansas late this morning. This convective
development suggests that subtle forcing for ascent within
northwesterly flow is beginning to advance across northern Kansas.
As it does so, isolated to scattered convective initiation is
possible farther east along a surface theta-e ridge/confluence axis
extending towards the Missouri Valley. Adjusting the 12Z TOP
sounding for current conditions suggests strong buoyancy (e.g.,
MLCAPE upwards of 3000 J/kg) is already present. In turn, robust
updraft accelerations and strong thunderstorm cores will remain
possible.

Relatively straight hodographs (somewhat parallel to the corridor of
initiation as well) suggest clusters of splitting cells will be the
preferred mode. The steep lapse rate environment and hot boundary
layer will be favorable for strong cold pool generation, and this
may encourage a few bowing segments that advance east/southeast
within the northwesterly flow environment. As such, damaging winds
will be the primary threat, although embedded supercell structures
will yield the potential for large hail as well.

Due to the subtle nature of large-scale ascent, there is some
uncertainty in the timing/coverage of downstream convection.
However, the severe threat appears to be increasing sufficiently
such that a watch may be needed within the next 1-2 hours.

..Picca/Guyer.. 07/19/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...SGF...EAX...TOP...ICT...GID...DDC...GLD...

LAT...LON   39359975 39739983 39939959 39939716 39869656 39689541
            39429493 38889461 38219471 37919480 37449564 37509629
            38079729 38539880 39359975 

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SPC MD 1080

MD 1080 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR EAST/SOUTHEAST NE…FAR NORTHEAST KS…FAR SOUTHWEST IA…FAR NORTHWEST MO

MD 1080 Image


Mesoscale Discussion 1080
NWS Storm Prediction Center Norman OK
1247 AM CDT Thu Jul 19 2018

Areas affected...East/Southeast NE...Far Northeast KS...Far
Southwest IA...Far Northwest MO

Concerning...Severe potential...Watch likely 

Valid 190547Z - 190745Z

Probability of Watch Issuance...95 percent

SUMMARY...Strong to severe wind gusts and hail are expected to
remain a threat during the next several hours as the cluster of
storms continues southeastward. WW likely.

DISCUSSION...Recent radar imagery continues to show a small but
well-defined convective system moving southeastward across eastern
NE at about 35 to 40 kt. Nocturnal stabilization has made the
downstream airmass less favorable for surface-based convection (i.e.
SBCIN is less than -50 J/kg based on recent mesoanalysis). Even so,
the very moist nature of the airmass, evidenced by dewpoints in the
mid 70s and 100mb mean mixing ratios around 16 g per kg, and at
least moderately steep mid-level lapse rates result in enough
instability to maintain elevated convection. Moisture gradient
between the drier conditions of the middle MS Valley and more moist
conditions across the central Plains will provide a favored track
for the system. As such, the general expectation is for the system
to continue southeastward for the next several hours, eventually
reaching far northeast KS and far northwest MO. Strong to severe
wind gusts and isolated hail appear probable as this system
continues southeastward and a watch will be needed to cover this
persisting threat.

..Mosier/Edwards.. 07/19/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...EAX...OAX...TOP...GID...

LAT...LON   40039804 41069843 41729809 42099709 41289555 40019502
            39489671 40039804 

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SPC MD 1079

MD 1079 CONCERNING SEVERE THUNDERSTORM WATCH 281… FOR MUCH OF EASTERN NEBRASKA

MD 1079 Image


Mesoscale Discussion 1079
NWS Storm Prediction Center Norman OK
0921 PM CDT Wed Jul 18 2018

Areas affected...Much of eastern Nebraska

Concerning...Severe Thunderstorm Watch 281...

Valid 190221Z - 190415Z

The severe weather threat for Severe Thunderstorm Watch 281
continues.

SUMMARY...A few storms capable of hail and locally strong wind gusts
remain possible across eastern Nebraska. Isolated storms may
eventually affect northern Kansas, but a watch may not be needed.

DISCUSSION...Storms across NE has remained largely cellular this
evening owing to lengthening hodographs and sufficient low-level
SRH. 00Z soundings from the area indicate a marginally unstable
environment with relatively poor lapse rates aloft, yet ample
low-level moisture. Some increase in the southerly low-level jet
this evening may support a continued severe threat over far southern
NE and into northern KS, as capping remains minimal. However, it is
unclear whether a new watch will need to be issued at this time,
especially if storms remain isolated.

..Jewell.. 07/19/2018

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...EAX...FSD...OAX...TOP...ICT...GID...LBF...

LAT...LON   39189903 41179936 41749933 42419898 42719855 42839805
            42819750 42739704 42449659 41919616 41139585 40629573
            39919595 39489620 39189672 39109739 38999810 39019849
            39189903 

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