SPC MD 1545

MD 1545 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR NORTHEAST KS…I-70 CORRIDOR OF MO

MD 1545 Image


Mesoscale Discussion 1545
NWS Storm Prediction Center Norman OK
0341 PM CDT Mon Aug 21 2017

Areas affected...Northeast KS...I-70 Corridor of MO

Concerning...Severe potential...Watch unlikely 

Valid 212041Z - 212215Z

Probability of Watch Issuance...20 percent

SUMMARY...Thunderstorm clusters capable of locally damaging wind and
isolated instances of hail are possible for the next few hours.
Watch issuance is considered unlikely.

DISCUSSION...A thunderstorm cluster has recently intensified near
Kansas City, to the north of an old outflow boundary that is
advancing slowly northward as an effective warm front across
northeast KS and central MO. While midlevel lapse rates are
relatively weak across the region, rich low-level moisture is
supporting MUCAPE of 2000-3000 J/kg north of the warm front. Veering
wind profiles noted in the EAX and TOP VWPs support some storm
organization. The potential exists for one or more upscale-growing
clusters to track eastward just north of the warm front this
afternoon. Some locally damaging wind risk will develop with any
clusters that can acquire a sufficiently strong cold pool. Buoyancy
may be sufficient for at least small hail, though the severe hail
risk should be limited by poor lapse rates and warm temperatures
aloft. 

With a nose of dry midlevel air moving into central MO, it is
unclear whether any long-lived cluster will be sustained north of
the warm front, but a marginal severe risk will continue across at
least northwest MO in the short term. Some backbuilding is possible
further west into northeast KS with time, as low-amplitude midlevel
features continue to track northeastward out of the southern High
Plains.

..Dean/Grams.. 08/21/2017

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

ATTN...WFO...LSX...SGF...EAX...TOP...

LAT...LON   39599601 39649420 39659307 39419148 38589156 38519243
            38529321 38609419 38759596 39169602 39599601 

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SPC MD 1537

MD 1537 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR NORTHEAST NE…WEST-CENTRAL/CENTRAL IA

MD 1537 Image


Mesoscale Discussion 1537
NWS Storm Prediction Center Norman OK
1114 PM CDT Sun Aug 20 2017

Areas affected...Northeast NE...West-Central/Central IA

Concerning...Severe potential...Watch possible 

Valid 210414Z - 210545Z

Probability of Watch Issuance...40 percent

SUMMARY...Thunderstorms capable of large hail are anticipated across
the region. Trends will be monitored for possible watch issuance.

DISCUSSION...Regional radar imagery has shown an increase in
thunderstorm activity over the past hour amidst a strengthening
low-level jet. This low-level jet will contribute to persistent warm
air advection/isentropic ascent within the frontal zone draped
across the region. Additionally, the low-level airmass upstream is
very moist, evidenced by surface dewpoints in the upper 60s/low 70s
and a mean mixing ratio of 16.7 g/kg on the 00Z TOP sounding.
Continued isentropic ascent within this moist airmass will result in
increasing storm coverage. Based on the 00Z OAX and recent RAP
sounding, storm bases will likely be around 850 mb/1 km.

These elevated storms will occur in an environment characterized by
steep mid-level lapse rates (7.7 deg C per km on the 00Z OAX
sounding) and moderate low and mid-level shear. Latest OAX VWP
showed strong directional shear within the lowest 3 km. These
environmental factors support strong, organized updrafts capable of
producing severe hail and a watch may be needed to cover the
anticipated severe threat.

..Mosier/Goss.. 08/21/2017

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

ATTN...WFO...DMX...FSD...OAX...

LAT...LON   41009435 41549572 41769721 42319778 42829726 42829604
            42549480 41949340 41149345 41009435 

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SPC MD 1530

MD 1530 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF SOUTHERN KANSAS TO THE OZARKS

MD 1530 Image


Mesoscale Discussion 1530
NWS Storm Prediction Center Norman OK
0231 PM CDT Sat Aug 19 2017

Areas affected...Portions of southern Kansas to the Ozarks

Concerning...Severe potential...Watch unlikely 

Valid 191931Z - 192130Z

Probability of Watch Issuance...5 percent

SUMMARY...A few thunderstorms may be capable of isolated large hail
and damaging winds this afternoon. However, the threat should remain
sufficiently limited in space, precluding watch issuance.

DISCUSSION...Isolated convection is gradually developing near/south
of a residual stationary front over southeastern Kansas this
afternoon. Ample boundary-layer moisture (e.g., surface dew points
into the lower/mid 70s) and diurnal heating are promoting strong
buoyancy, characterized by MLCAPE values over 3000 J/kg. While flow
beneath 500mb is modest, veering with height is coupled with more
vigorous upper-level flow around 50 kt. Therefore, a few cells may
exhibit transient updraft organization. Combined with the
aforementioned buoyancy, such organization may yield isolated large
hail. Additionally, dry mid-level air, while potentially stunting
weaker updrafts, will enhance downdraft momentum in stronger cores,
with an attendant threat of isolated damaging gusts. 

The 20Z convective outlook will extend marginal (5%) hail and wind
probabilities southeastward to include parts of this region.
However, low storm coverage and a lack of greater organization
should preclude watch issuance.

..Picca/Weiss.. 08/19/2017

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

ATTN...WFO...LZK...SGF...EAX...TSA...TOP...ICT...

LAT...LON   37009675 37409766 37879810 38249799 38419757 38249566
            37569337 37339309 36629224 36059255 36119341 36699518
            37009675 

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SPC MD 1525

MD 1525 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF EASTERN KS AND NORTHERN/CENTRAL MO

MD 1525 Image


Mesoscale Discussion 1525
NWS Storm Prediction Center Norman OK
0550 PM CDT Fri Aug 18 2017

Areas affected...Portions of eastern KS and northern/central MO

Concerning...Severe potential...Watch unlikely 

Valid 182250Z - 190045Z

Probability of Watch Issuance...20 percent

SUMMARY...Some increase in an isolated threat for strong to damaging
winds and large hail may occur over the next several hours. Watch
issuance appears unlikely at this time, although convective trends
will be closely monitored.

DISCUSSION...A secondary vorticity maximum located over southeastern
NE is embedded within a large-scale upper trough across the Upper
Midwest. At the surface, a low is present over southern IA, with a
weak boundary/front trailing southwestward across northern MO into
northeastern KS per surface observations and trends in visible
satellite imagery. A band of convection has recently formed
along/just north of the surface boundary across northern MO. Given
its fast motion, this activity is probably elevated as of 2245Z.
Several more robust thunderstorms have also formed along the KS/MO
border to the north of Kansas City. This convection appears to be
surface based, and given the presence of strong instability to the
south of the boundary (MLCAPE 2000-3000 J/kg), tendency may be for
these thunderstorms to develop south-southeastward along an
instability gradient this evening.

Although low-level flow remains modest, west/northwesterly winds do
increase at mid/upper levels, and 30-40 kt of effective bulk shear
should provide some potential for updraft organization. Given the
linear forcing of the surface boundary, a cluster or short line
segments may develop from the convection located across the KS/MO
border, with an attendant isolated threat for both damaging winds
and large hail. Convective evolution of the elevated band of storms
through this evening in northern MO is less clear. At this time, the
severe threat may remain too confined in space/time to warrant watch
issuance.

..Gleason/Edwards.. 08/18/2017

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

ATTN...WFO...LSX...DVN...SGF...EAX...TOP...

LAT...LON   39429532 39849476 40059358 40569252 40569174 40019156
            39149160 38729199 38219282 37859454 38229535 39079553
            39429532 

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SPC MD 1509

MD 1509 CONCERNING SEVERE THUNDERSTORM WATCH 453… FOR PORTIONS OF SOUTHEAST KANSAS…WESTERN MISSOURI…AND NORTHERN OKLAHOMA

MD 1509 Image


Mesoscale Discussion 1509
NWS Storm Prediction Center Norman OK
0447 PM CDT Wed Aug 16 2017

Areas affected...Portions of southeast Kansas...western
Missouri...and northern Oklahoma

Concerning...Severe Thunderstorm Watch 453...

Valid 162147Z - 162315Z

The severe weather threat for Severe Thunderstorm Watch 453
continues.

SUMMARY...Thunderstorms, at times severe, will continue to develop
across WW 453 this evening. Through late evening, storms will likely
merge into eastward-moving lines/clusters, with the severe threat
transitioning primarily to damaging winds.

DISCUSSION...Regional radar mosaic data depict several clusters of
strong/severe storms have developed along both a cold front and
remnant outflow boundary over southern Kansas. Cells have exhibited
a somewhat disorganized evolution so far, characterized by splits
and mergers. This evolution is likely the result of continued
front-parallel deep-layer flow and only modest west/southwesterly
winds around 700mb. Despite this, steep mid-level lapse rates and
500mb flow around 50 kt (based on recent KVNX VWP data) suggest
large hail remains a threat with any semi-discrete cells. However,
the overall severe threat should further transition to damaging
winds this evening, as storms congeal into small forward-propagating
segments and push towards western Missouri.

..Picca.. 08/16/2017

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

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

LAT...LON   37199865 38379595 38759460 38709357 38429327 37189344
            36769390 36559601 36699813 36859860 37199865 

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SPC MD 1507

MD 1507 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR PORTIONS OF SOUTHERN/EASTERN KANSAS AND FAR NORTHERN OKLAHOMA

MD 1507 Image


Mesoscale Discussion 1507
NWS Storm Prediction Center Norman OK
0133 PM CDT Wed Aug 16 2017

Areas affected...Portions of southern/eastern Kansas and far
northern Oklahoma

Concerning...Severe potential...Watch likely 

Valid 161833Z - 162030Z

Probability of Watch Issuance...95 percent

SUMMARY...Scattered thunderstorms are forecast to develop by 2-3 PM
CDT, and a few of these storms will likely become severe with large
hail, damaging winds, and perhaps a couple tornadoes. Some of the
large hail could be over two inches in diameter. A watch will likely
be needed within the next couple of hours.

DISCUSSION...Satellite imagery and surface analysis early this
afternoon depict a somewhat complex pattern across parts of Kansas
and far northern Oklahoma. On the synoptic scale, a cold front
extends from western Oklahoma northeastward to a low over the mid
Missouri Valley. Furthermore, a remnant outflow boundary from
morning convection extends from the front over south-central Kansas
east to the Ozarks. Near/south of this boundary, rich low-level
moisture (e.g., 15.2 g/kg mean mixing ratio on the 18Z Springfield,
MO sounding) is combining with diurnal heating to promote MLCAPE
values upwards of 2000-3000 J/kg. While weak inhibition remains,
continued surface heating and mid-level cooling/moistening (on the
fringe of a broad vorticity maximum) should be sufficient for
convective initiation by mid afternoon. 

East/northeastward advection of steeper mid-level lapse rates
towards the region, combined with effective shear around 35-40 kt,
will be favorable for a few initially semi-discrete cells capable of
large hail (some potentially greater than two inches in diameter).
Additionally, backed low-level flow near the outflow boundary may
yield enough storm-relative helicity for low-level rotation and a
couple tornadoes in any semi-discrete cells late this afternoon.
However, due to generally front-parallel deep-layer mean flow,
convective mode should quickly evolve to clusters and line segments,
transitioning the primary threat to damaging winds this evening as
cells gradually spread east.

With storms developing by 20 UTC (3 PM CDT), watch issuance will
likely be needed within the next 1-2 hours.

..Picca/Weiss.. 08/16/2017

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

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

LAT...LON   36679843 36939896 37179908 37449857 38039768 38709649
            38849595 38769501 38489490 37509476 36889499 36649570
            36579739 36679843 

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