SPC MD 1795

MD 1795 CONCERNING HEAVY SNOW FOR CENTRAL NY

MD 1795 Image


Mesoscale Discussion 1795
NWS Storm Prediction Center Norman OK
0930 PM CST Mon Dec 11 2017

Areas affected...Central NY

Concerning...Heavy snow 

Valid 120330Z - 120930Z

SUMMARY...Snowfall rates will increase gradually through 06-09z,
with peak rates likely to exceed 1 inch per hour from about 07-12z.

DISCUSSION...In association with a midlevel shortwave trough
approaching the upper OH Valley, a deformation snow band has been
developing eastward over Lake Erie.  Low-midlevel warm
advection/ascent in advance of the trough, as well as weak
frontogenesis, will support additional eastward expansion of the
snow band across central NY through the early morning hours. 
Top-down saturation of the column is just beginning across western
into central NY, and snowfall rates will increase as column
saturation develops eastward and forcing for ascent increases
through the early morning hours.  Peak snowfall rates should
approach or exceed 1 inch per hour, and may persist for 3-6 hours at
locations within the expected corridor of the snow band.

..Thompson.. 12/12/2017

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

ATTN...WFO...BTV...ALY...BGM...BUF...

LAT...LON   43217361 43007412 42747497 42497608 42457687 42517744
            42667771 43037760 43837544 44037419 43947361 43617347
            43217361 

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SPC MD 1787

MD 1787 CONCERNING HEAVY SNOW FOR FAR WEST-CENTRAL MS…CENTRAL AL…NORTHWEST GA

MD 1787 Image


Mesoscale Discussion 1787
NWS Storm Prediction Center Norman OK
0755 AM CST Fri Dec 08 2017

Areas affected...Far West-central MS...Central AL...Northwest GA

Concerning...Heavy snow 

Valid 081355Z - 081700Z

SUMMARY...Occasionally moderate to heavy snowfall (i.e. snowfall
rates around 1 inch per hour) are possible over the next several
hours across portions of central AL and northwest GA

DISCUSSION...Recent surface observations show that temperatures
across central AL and northwest GA have cooled enough to support
snow. Several sites are already reporting moderate snow with
isolated/brief instances of heavy snow (i.e. visibility less than
1/4SM) also being reported. Relatively heavier band of precipitation
is currently ongoing across southeast MS/southwest AL and its
northeasterly motion is expected to take it into central AL and
northwest GA over the next few hours. As a result, snowfall rates
may occasionally top 1 inch per hour in isolated locations.
Subfreezing surface wet-bulb temperatures are expected to remain
north of a line from MEI northeastward to RMG, keeping areas south
of this line predominately rain.

..Mosier.. 12/08/2017

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

ATTN...WFO...GSP...FFC...BMX...HUN...JAN...

LAT...LON   33358873 33918740 34848522 34838426 34348345 33448484
            32658684 32188908 33358873 

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SPC MD 1728

MD 1728 CONCERNING SEVERE THUNDERSTORM WATCH 502… FOR EASTERN KANSAS AND WESTERN MISSOURI

MD 1728 Image


Mesoscale Discussion 1728
NWS Storm Prediction Center Norman OK
0810 PM CDT Sat Oct 21 2017

Areas affected...Eastern Kansas and western Missouri

Concerning...Severe Thunderstorm Watch 502...

Valid 220110Z - 220245Z

The severe weather threat for Severe Thunderstorm Watch 502
continues.

SUMMARY...An isolated severe wind risk persists across remaining
portions of WW 502.  A new WW is being considered downstream of WW
502 - particularly for portions of southeastern Kansas and
southwestern Missouri.

DISCUSSION...A line of storms continues to propagate eastward across
portions of WW 502 - generally along a line from near LWD to MKC to
CNU.  Most of the line has been sub-severe over the past hour or so,
although a 59 mph wind gust was reported in Burbank, OK recently -
and that storm should propagate into southern portions of WW 502
with time.  This isolated severe wind risk - most concentrated in
southeastern Kansas and vicinity - will eventually reach the eastern
extent of the the watch over the next 1-1.5 hours.  A new severe
thunderstorm watch is being considered as ongoing convection - aided
by 1000-1500 J/kg MLCAPE and an increasing low-level jet across the
region - approaches southwestern Missouri.

..Cook.. 10/22/2017

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

ATTN...WFO...LSX...SGF...DMX...EAX...TSA...TOP...ICT...

LAT...LON   40639324 40439391 39279498 37549647 37189654 37009571
            36959499 36909458 36519458 36529347 36509267 37429252
            38919258 40249302 40639324 

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SPC MD 1725

MD 1725 CONCERNING SEVERE THUNDERSTORM WATCH 502… FOR EASTERN KANSAS…WESTERN MISSOURI…AND FAR SOUTHERN IOWA

MD 1725 Image


Mesoscale Discussion 1725
NWS Storm Prediction Center Norman OK
0538 PM CDT Sat Oct 21 2017

Areas affected...Eastern Kansas...western Missouri...and far
southern Iowa

Concerning...Severe Thunderstorm Watch 502...

Valid 212238Z - 212345Z

The severe weather threat for Severe Thunderstorm Watch 502
continues.

SUMMARY...The risk of damaging wind gusts and isolated hail
continues along and ahead of a squall line in western portions of WW
502.

DISCUSSION...Storms have mostly congealed into linear segments along
an outflow that extends from near STJ to TOP to just southeast of
ICT.  Several of these storms are mostly behind this outflow and
slightly elevated atop a stable boundary layer - especially across
south-central Kansas.  Hail will be the primary threat with this
activity, while damaging wind gusts will be the primary threat with
convection along and ahead of the boundary - particularly with
storms near and east of the Topeka area that have exhibited bowing
segments.  An additional risk for surface based activity will occur
with pre-frontal convection migrating northeastward from
north-central Oklahoma.

West of this line, the severe threat is diminishing as thermodynamic
profiles stabilize behind the cold front.  The severe thunderstorm
watch may be cancelled early for areas behind the front.  See
attendant Watch Status messages for further guidance.

..Cook.. 10/21/2017

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

ATTN...WFO...SGF...DMX...EAX...TSA...OAX...TOP...ICT...OUN...

LAT...LON   40729504 40969470 41019363 40739272 40309272 39089353
            37719455 36889537 36909646 36949752 37009813 37559787
            38499716 38979670 40729504 

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SPC MD 1722

MD 1722 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR WESTERN AND CENTRAL OK AND PART OF WESTERN NORTH TX

MD 1722 Image


Mesoscale Discussion 1722
NWS Storm Prediction Center Norman OK
0236 PM CDT Sat Oct 21 2017

Areas affected...Western and central OK and part of western North TX

Concerning...Severe potential...Watch likely 

Valid 211936Z - 212130Z

Probability of Watch Issuance...95 percent

SUMMARY...A new severe-weather watch will be coordinated soon across
portions of the southern Plains.  Thunderstorms are expected to
develop by late afternoon across western Oklahoma and into parts of
western North Texas, with storms becoming severe producing large
hail and perhaps a tornado with the initial activity.  Damaging
winds will become a greater threat as storms form a line, advancing
east across central Oklahoma into the evening.

DISCUSSION...Despite the lack of lightning so far, trends in visible
satellite imagery indicated sustained and deepening convection along
the portion of the cold front advancing southward through western OK
with some cooling of cloud tops.  Farther south into western North
TX, visible imagery indicated likely surface-based cumulus clouds
forming from southeast of CDS into Wilbarger County.  Objective
analyses indicated an increase of low-level convergence across this
latter area and the cold front, as a dryline shifts east through
northwest TX.  The warm sector has become moderately unstable
(MLCAPE 2000-2500 J/kg) with weakening of surface-based inhibition
per objective analyses along and just east of the surface
boundaries.  Additional surface heating and an increase in
large-scale ascent, as an upper trough moves east into the southern
Plains, are expected to aid in further weakening of the cap and
strengthening storm development from late this afternoon through the
evening.

An increase in deep-layer shear will support supercells with the
initial activity across western OK and western North TX, while
upscale growth is expected into the evening, with damaging winds
becoming the primary threat as a squall line evolves into central
OK.

..Peters/Thompson.. 10/21/2017

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

ATTN...WFO...TSA...FWD...OUN...

LAT...LON   34299996 35599953 36949829 36949689 36919663 36229668
            35069706 34159745 33689809 33519899 33849990 34299996 

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SPC MD 1721

MD 1721 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR EASTERN KANSAS…FAR SOUTHEAST NEBRASKA…FAR SOUTHWEST IOWA AND NORTHWEST MISSOURI

MD 1721 Image


Mesoscale Discussion 1721
NWS Storm Prediction Center Norman OK
0123 PM CDT Sat Oct 21 2017

Areas affected...eastern Kansas...far southeast Nebraska...far
southwest Iowa and northwest Missouri

Concerning...Severe potential...Watch likely 

Valid 211823Z - 212100Z

Probability of Watch Issuance...95 percent

SUMMARY...Thunderstorms are expected to develop along the
east-southeastward progressing cold front across eastern Kansas
later this afternoon. Once initiation occurs, storms will quickly
intensify with damaging wind gusts, hail and a tornado or two
possible into the evening hours. A watch will likely be needed by
20-21z.

DISCUSSION...Breaks in low level clouds have allowed temperatures to
warm into the mid to upper 70s across much of eastern KS early this
afternoon. With dewpoints in the low and mid 60s, MLCAPE values have
increased to 1500-2000 J/kg. The VAD wind profile from the DDC radar
also has shown a slight increase in midlevel winds over the last 30
minutes or so, suggesting the shortwave impulse over northeast NM is
beginning to eject east/northeast into the Plains. Furthermore,
cumulus along the front from far northwest OK into central/eastern
KS and southeast NE is becoming increasingly congested with some
vertical growth evident. In conjunction with hi-res HRRR guidance,
this suggests convective initiation should occur within the next
couple of hours.

Steep midlevel lapse rates and effective shear in excess of 35 kt
will aid in storms quickly becoming severe with at least a brief
window of opportunity for semi-discrete cells. However, the quickly
progressing cold front and front-parallel deep-shear vectors will
result in rather fast upscale growth. Any cells that can stay
semi-discrete will pose a threat for large hail and damaging wind.
Once upscale growth occurs, a transition to mainly a damaging wind
threat is expected. While forecast low-level hodographs are
unimpressive, they are adequate for low-end tornado potential and a
tornado or two can not be ruled out either in an isolated cell or
within embedded mesovorticies along the leading edge of the squall
line. A watch will likely be needed between 20-21z.

..Leitman/Thompson.. 10/21/2017

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

ATTN...WFO...SGF...DMX...EAX...OAX...TOP...ICT...

LAT...LON   37799510 37369554 37069617 37049691 37009757 37059809
            37249826 37629815 37879805 38379762 39069719 39599690
            40569669 41019645 41289596 41299538 41179467 40929423
            40579408 40009408 38909433 38309470 37799510 

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SPC MD 1716

MD 1716 CONCERNING SEVERE THUNDERSTORM WATCH 500… FOR SOUTHEAST KS…FAR SOUTHWEST MO

MD 1716 Image


Mesoscale Discussion 1716
NWS Storm Prediction Center Norman OK
0732 PM CDT Sat Oct 14 2017

Areas affected...Southeast KS...Far Southwest MO

Concerning...Severe Thunderstorm Watch 500...

Valid 150032Z - 150200Z

The severe weather threat for Severe Thunderstorm Watch 500
continues.

SUMMARY...The threat for locally damaging wind and perhaps
marginally severe hail continues across southeast KS. While storms
will eventually move into southwest MO, a weakening trend is
expected later this evening as a cold front sweeps through the area.

DISCUSSION...Multiple potentially severe bowing segments have
evolved across southeast KS over the last 1-2 hours. With moderate
instability and relatively strong low-level flow and effective shear
in place, these features will continue to pose a threat of damaging
wind and localized hail for the next 1-2 hours as they move into
southeast KS and west-central MO. The strongest of the bowing
segments is likely to move east-northeast into Tornado Watch 501,
while the trailing segments will eventually impact the remainder of
southeast KS into southwest MO. 

A strong cold front is approaching the southeast KS from the north
and will overtake the strongest convection by mid-evening. With the
strongest large-scale ascent moving northeast away from the region
and weaker moisture and instability with eastward extent (as noted
in 00Z SGF sounding), a weakening trend is expected with time as
convection becomes increasingly undercut over southwest MO. Some
local extension of the WW 500 may be required in the short term
across southwest MO, but at this time new watch issuance is
unlikely.

..Dean/Guyer.. 10/15/2017

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

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

LAT...LON   37059759 37499764 37889687 38199602 38409533 38519489
            38499468 38229439 37989368 37139379 37059759 

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SPC MD 1712

MD 1712 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR CENTRAL INTO NORTHEAST KANSAS

MD 1712 Image


Mesoscale Discussion 1712
NWS Storm Prediction Center Norman OK
0240 PM CDT Sat Oct 14 2017

Areas affected...Central into northeast Kansas

Concerning...Severe potential...Watch likely 

Valid 141940Z - 142215Z

Probability of Watch Issuance...80 percent

SUMMARY...Severe storms are expected to form by 21-22Z over parts of
central Kansas, with increasing coverage by late afternoon and
evening into eastern Kansas and western Missouri. Large hail and
damaging winds will be the primary threats.

DISCUSSION...Visible imagery shows CU beginning to form along a
pre-frontal trough across central KS where a narrow plume of strong
heating persists. This area of heating lies just north of an
extensive midlevel moist plume extending from the TX Panhandle into
northeastern KS, also coincident with the western fringe of a 40 kt
low-level jet and acting as an effective warm front. Showers are
also beginning to consolidate into more intense cores within this
moist plume. 

As the cold front continues to develop southeastward, storms should
form along it, and also invigorate the leading storms currently
extending from near Wichita to Kansas City. Initially, supercells
are possible, with long hodographs favoring damaging hail and winds.
As the front deepens with time, storms will consolidate into a
squall line, with strong shear oriented parallel to the boundary
possibly resulting in a QLCS.

..Jewell/Hart.. 10/14/2017

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

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

LAT...LON   38869766 39149703 39479614 39669516 39639494 39459478
            39209466 38899467 38599474 38339513 38109570 37599677
            37229744 37059797 37059865 37139892 37309901 37579911
            37809908 38159895 38259864 38649798 38869766 

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SPC MD 1709

MD 1709 CONCERNING SEVERE THUNDERSTORM WATCH 499… FOR SOUTHEAST KS…NORTHEAST OK

MD 1709 Image


Mesoscale Discussion 1709
NWS Storm Prediction Center Norman OK
0954 PM CDT Mon Oct 09 2017

Areas affected...Southeast KS...Northeast OK

Concerning...Severe Thunderstorm Watch 499...

Valid 100254Z - 100400Z

The severe weather threat for Severe Thunderstorm Watch 499
continues.

SUMMARY...WW will not be reissued.

DISCUSSION...While scattered thunderstorms continue along the
frontal zone from southeast KS into portions of north-central TX,
Updrafts have struggled to produce hail in excess of 1" for much of
the evening. Large-scale forcing will spread across the southern
Plains overnight and should contribute to additional thunderstorm
activity along the boundary extending south into north TX. Even so,
buoyancy appears inadequate for organized severe.

..Darrow.. 10/10/2017

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

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

LAT...LON   35249671 38119726 38129486 35269441 35249671 

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SPC MD 1708

MD 1708 CONCERNING SEVERE THUNDERSTORM WATCH 499… FOR NORTHEAST OK…SOUTHEAST KS

MD 1708 Image


Mesoscale Discussion 1708
NWS Storm Prediction Center Norman OK
0651 PM CDT Mon Oct 09 2017

Areas affected...Northeast OK...Southeast KS

Concerning...Severe Thunderstorm Watch 499...

Valid 092351Z - 100115Z

The severe weather threat for Severe Thunderstorm Watch 499
continues.

SUMMARY...Isolated hail will continue to be the primary threat with
storms this evening.

DISCUSSION...Scattered convection is beginning to mature along the
advancing wind shift over northeast OK with lightning now detected
with updrafts over Osage County. Frontal convection may gradually
increase across northeast OK over the next few hours but overall
intensity of this activity may struggle to produce more than
isolated large hail. Latest MRMS data at times exhibits hail
approaching 1" but mostly marginally severe. One reason may be that
large-scale forcing for ascent lags this region considerably. In
addition, the onset of boundary-layer cooling will result in
updrafts becoming increasingly elevated in nature. Even so, some
threat for isolated severe will continue for the next few hours.

..Darrow.. 10/09/2017

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

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

LAT...LON   35259672 38109726 38129487 35269441 35259672 

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