SPC MD 30

MD 0030 CONCERNING HEAVY SNOW FOR NORTH-CENTRAL/NORTHEAST KS…SOUTHEAST/EAST-CENTRAL NE…SOUTHWEST/SOUTH-CENTRAL IA…FAR NORTHWEST MO

MD 0030 Image


Mesoscale Discussion 0030
NWS Storm Prediction Center Norman OK
1041 AM CST Mon Jan 25 2021

Areas affected...North-Central/Northeast KS...Southeast/East-Central
NE...Southwest/South-Central IA...Far Northwest MO

Concerning...Heavy snow 

Valid 251641Z - 252245Z

SUMMARY...Ongoing heavy snow across southeastern NE and
north-central/far northeast KS is expected to continue for next
several hours. Additionally, gradual eastward expansion of this
heavy snow into southwest IA and far northwest MO is anticipated.

DISCUSSION...Recent surface observations show numerous locations
across southeast NE and adjacent north-central KS reporting moderate
to heavy snow. Satellite and radar imagery show the dry slot is
currently moving through central KS, suggesting much of southeast NE
will remain within the band of heavy snow for at least the next
several hours. Additionally, with the shortwave trough approaching
the region, lift will likely intensify, resulting in increased
snowfall rates and the potential for up to 2" per hour (particularly
across far southeast NE). 

As the overall system moves northeastward, the area of heavy snow is
expected to do likewise, bringing snowfall rates over 1" per hour in
southwest/south-central IA and far northwest MO during the next
several hours. Once established, these high snowfall rates are
expected to last for 3+ hours.

..Mosier.. 01/25/2021

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

ATTN...WFO...DMX...EAX...OAX...TOP...ICT...GID...DDC...GLD...

LAT...LON   40759933 41589813 42089667 42219426 41979312 41359273
            40409310 39999373 39669519 39359650 39129769 39119913
            39450003 40759933 

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SPC MD 28

MD 0028 CONCERNING HEAVY SNOW FOR PORTIONS OF KS AND SOUTHERN NE

MD 0028 Image


Mesoscale Discussion 0028
NWS Storm Prediction Center Norman OK
0458 AM CST Mon Jan 25 2021

Areas affected...Portions of KS and southern NE

Concerning...Heavy snow 

Valid 251058Z - 251700Z

SUMMARY...Heavy snow, with rates of 1-2 inches per hour, will likely
develop northeastward across Kansas and southern Nebraska this
morning.

DISCUSSION...Strong forcing for ascent and frontogenetic lift in the
low levels, associated with a northeastward-ejecting shortwave
trough, will aid in the development of a heavy snow band across
parts of KS into southern NE this morning. An initial mix of wintry
precipitation across parts of southwestern into central KS is
expected to quickly transition to snow as low/mid-level temperatures
cool with the approaching shortwave trough. Pronounced lift through
the saturated dendritic growth zone will likely favor heavy snow
with rates of at least 1 inch per hour for several hours in a
southwest to northeast oriented band across KS. Higher rates,
perhaps up to 2 inches per hour, appear possible on a localized
basis. This heavy snow band should shift into parts of southern NE
by mid to late morning. A very narrow corridor of freezing
rain/sleet may occur on the southeastern fringe of the band, where a
modest low-level warm nose should remain.

..Gleason.. 01/25/2021

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

ATTN...WFO...OAX...TOP...ICT...GID...DDC...GLD...

LAT...LON   37660004 37430072 38230133 39080121 39970021 40839872
            41169726 40999629 40509581 40059572 39659589 39149680
            37660004 

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SPC MD 6

MD 0006 CONCERNING FREEZING RAIN FOR EASTERN KS…CENTRAL/NORTHERN MO…WEST-CENTRAL IL

MD 0006 Image


Mesoscale Discussion 0006
NWS Storm Prediction Center Norman OK
0233 AM CST Fri Jan 01 2021

Areas affected...eastern KS...central/northern MO...west-central IL

Concerning...Freezing rain 

Valid 010833Z - 011330Z

SUMMARY...Moderate to heavy freezing rain is expected to shift
northward across eastern KS into central/northern MO and
west-central IL through the early morning hours.

DISCUSSION...Moderate to heavy freezing rain has been noted recently
across southeast KS toward the I-44 corridor in southwest and
central MO. Freezing rain rates have been as high as 0.05 in/hr in
these locations. A more pronounced/stronger deformation region has
developed northward toward the I-70 corridor from eastern KS into
central MO as the upper low continues to shift northward from north
Texas into southern OK, and is evident in water vapor loops over the
past hour. As midlevel moistening continues, freezing rain will
develop northward and increase in intensity through early morning.
Forecast soundings suggest precipitation type should predominantly
be freezing rain. However, some sleet or snow could mix in at times
as modest midlevel cooling occurs on the back side of the mid/upper
low, resulting in a deepening isothermal layer around 900-750 mb.
Once freezing rain begins, rates greater than 0.05 inches per 3
hours are expected for several hours.

..Leitman.. 01/01/2021

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

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

LAT...LON   38299632 38719617 39179535 39379493 39859363 40269171
            40329089 40209034 39958996 39638990 38829040 38279114
            37739213 37269334 37159455 37329560 37629611 37989626
            38299632 

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SPC MD 1896

MD 1896 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR FAR EASTERN SOUTH CAROLINA INTO SOUTHERN NORTH CAROLINA

MD 1896 Image


Mesoscale Discussion 1896
NWS Storm Prediction Center Norman OK
0226 PM CST Thu Dec 31 2020

Areas affected...far eastern South Carolina into southern North
Carolina

Concerning...Severe potential...Watch unlikely 

Valid 312026Z - 312230Z

Probability of Watch Issuance...5 percent

SUMMARY...Recent convective development in eastern South Carolina
may pose an isolated wind/tornado risk this afternoon.  A WW
issuance is not anticipated due to the isolated nature of the
threat.

DISCUSSION...A small cluster of lightning-producing convection has
evolved near Horry County, SC over the past hour or so, with modest
but increasing organization noted on local radar.  The increase in
intensity is likely aided by an advancing, low-amplitude mid-level
wave evident on water vapor imagery and objective analysis.  The
storms are in a marginally unstable environment (with over 500 J/kg
MUCAPE in the pre-storm environment).  However, the presence of
strong updrafts (and nearly 40kft echo tops) suggests that the
storms may be taking advantage of the 40-50 kts of environmental
deep shear, fostering organization.  Additionally, the presence of
150-200 m2/s2 0-3km SRH may foster rotation in a few of the storms,
enhancing any localized risk of a damaging wind gust or perhaps a
tornado.  The overall risk should be localized and isolated given
the marginal nature of the instability, however, precluding the need
for a WW.

..Cook/Grams.. 12/31/2020

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

ATTN...WFO...MHX...RAH...ILM...

LAT...LON   34407946 34787873 34977786 34947720 34617697 33757764
            33297857 33267927 33777969 34177955 34407946 

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SPC MD 1884

MD 1884 CONCERNING WINTER MIXED PRECIPITATION FOR NORTHEAST KS…EASTERN NE…SOUTHWEST/CENTRAL IA…NORTHERN MO

MD 1884 Image


Mesoscale Discussion 1884
NWS Storm Prediction Center Norman OK
1002 AM CST Tue Dec 29 2020

Areas affected...Northeast KS...Eastern NE...Southwest/central
IA...Northern MO

Concerning...Winter mixed precipitation 

Valid 291602Z - 292100Z

SUMMARY...Moderate to occasionally heavy winter precipitation will
continue into this afternoon. The snow/freezing rain and freezing
rain/rain lines should gradually shift northward with time, with
some sleet possible within the snow/freezing rain transition zone.

DISCUSSION...At 16Z, a broad plume of winter precipitation is
ongoing from central KS into portions of IA/NE and northern MO, with
embedded convective elements noted across KS and moving into
southeast NE/southwest IA/northwest MO. This precipitation will be
sustained into this afternoon, as strong low-level warm advection
maintains ascent in advance of a complex mid/upper-level trough
moving into the central/northern Plains. The warm advection will
also result in a northward transition of the snow/freezing rain and
freezing rain/rain lines with time. Some sleet will be possible
within the snow/freezing rain transition zone, though surface
observations and forecast soundings indicate that freezing rain and
snow will remain the predominant precip types for at least the
remainder of the morning. 

While widespread and occasionally moderate/heavy, precipitation has
thus far been somewhat disorganized, with heavier rates being
relatively transient at any given location. However, heavier
precipitation over KS is expected to spread northeastward at a
faster rate than the precip type transition zones, resulting in more
widespread snow rates of 1+ inch per hour across far eastern NE into
western/central IA by early afternoon, and freezing rain rates of
0.05+ inches/hour from southeast NE/far northeast KS into northern
MO. Increasing frontogenesis within the 900-700 mb layer will
support the potential for more organized banding and even greater
snowfall rates by mid afternoon, primarily across portions of
southern/central IA.

..Dean.. 12/29/2020

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

ATTN...WFO...LSX...DVN...DMX...EAX...OAX...TOP...GID...

LAT...LON   41009151 40089230 39149383 38629549 39019681 39389772
            40649732 41559684 42059483 42249371 42239259 41909176
            41009151 

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SPC MD 1883

MD 1883 CONCERNING WINTER MIXED PRECIPITATION FOR MUCH OF KS AND FAR NORTHWESTERN OK

MD 1883 Image


Mesoscale Discussion 1883
NWS Storm Prediction Center Norman OK
0400 AM CST Tue Dec 29 2020

Areas affected...Much of KS and far northwestern OK

Concerning...Winter mixed precipitation 

Valid 291000Z - 291600Z

SUMMARY...Freezing rain should occur this morning before gradually
turning to rain from south to north. Freezing rain rates may exceed
0.05 inch per 3 hours. Some snow/sleet may also mix with the
freezing rain, mainly across parts of northern Kansas.

DISCUSSION...A 40-50+ kt southerly low-level jet will continue to
transport moisture northward across the southern/central Plains this
morning. Strong forcing for ascent associated with this low-level
jet has encouraged the development of scattered to numerous showers
across northern OK and much of central/eastern KS. An initially dry
sub-cloud layer across these areas is gradually becoming saturated
as precipitation continues. Evaporative cooling to the surface wet
bulb temperature should result in a period of freezing rain for at
least a few hours this morning across far northwestern OK and much
of KS, where surface air temperatures are or will soon fall below
freezing. The light to moderate and showery precipitation should
support freezing rain rates around 0.05 inch per 3 hours, with
locally higher rates possible with convection that may produce
isolated lightning flashes with very weak elevated instability.
Still, ice accretion may remain limited to elevated surfaces for
most locations due to the marginal surface temperatures. The best
potential for ice accretion appears to be across parts of
north-central into northeastern KS, where surface temperatures
should generally remain below freezing this morning.

Continued robust low-level warm advection is expected to gradually
erode the near-surface sub-freezing layer from south to north across
this region through the morning, as surface winds veer from easterly
to southeasterly. Accordingly, a transition from freezing rain to
rain should occur across far northwestern OK and parts of
southern/central KS by 16Z (10 AM CST). A mix of freezing rain,
sleet, and/or snow also appears possible across mainly northern KS,
where the low-level warm nose will not be as pronounced compared to
locations farther south.

..Gleason.. 12/29/2020

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

ATTN...WFO...EAX...TOP...ICT...OUN...GID...DDC...GLD...AMA...

LAT...LON   37899794 37419871 36699916 36439964 36670051 37430083
            38250072 39129999 39889814 39959681 39879573 39489508
            38759494 38309587 38109708 37899794 

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SPC MD 1874

MD 1874 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR CENTRAL/EASTERN FL PANHANDLE AND SOUTHWEST GA

MD 1874 Image


Mesoscale Discussion 1874
NWS Storm Prediction Center Norman OK
1211 PM CST Thu Dec 24 2020

Areas affected...Central/eastern FL Panhandle and southwest GA

Concerning...Severe potential...Watch unlikely 

Valid 241811Z - 241945Z

Probability of Watch Issuance...20 percent

SUMMARY...The threat for locally damaging winds and a brief tornado
will exist along a pre-frontal QLCS that should progress east from
the central to the eastern FL Panhandle and southwest GA. The
magnitude of these threats are expected to be small enough to
preclude a weather watch issuance in the near-term, but
observational trends will continue to be monitored.

DISCUSSION...The northern portion of a short QLCS depicted some
organized structure in radar reflectively as it moved onshore in
Gulf County, FL with overshooting CB tops in 1-min visible satellite
imagery, before waning farther inland. The KTLH VWP continues to
sample 50-60 kt southwesterlies through the 1-3 km AGL layer.
However, the boundary layer has struggled to warm greatly in this
portion of the Panhandle and southwest GA with surface temperatures
holding from 65-70 F. This suggests strong gusts capable of
localized tree damage should be the primary hazard with the line.

Convection just east of the Tallahassee area has shown broad and
weak low-level rotation at times. This activity remains on the
leading edge of surface-based buoyancy, which will likely limit
potential for more sustained supercell development. The overall
tornado threat may remain low this afternoon.

..Grams/Guyer.. 12/24/2020

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

ATTN...WFO...JAX...TAE...

LAT...LON   30478480 30778456 31018433 31068418 31268400 31248319
            30918293 30278319 29998338 29848395 29688476 29688515
            30478480 

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SPC MD 1806

MD 1806 CONCERNING SEVERE THUNDERSTORM WATCH 512… FOR PORTIONS OF LONG ISLAND NEW YORK…CONNECTICUT…MASSACHUSETTS…RHODE ISLAND

MD 1806 Image


Mesoscale Discussion 1806
NWS Storm Prediction Center Norman OK
0837 PM CST Sun Nov 15 2020

Areas affected...Portions of Long Island New
York...Connecticut...Massachusetts...Rhode Island

Concerning...Severe Thunderstorm Watch 512...

Valid 160237Z - 160430Z

The severe weather threat for Severe Thunderstorm Watch 512
continues.

SUMMARY...The severe threat continues across Severe Thunderstorm
Watch 0512. Damaging gusts are expected to accompany a fast-moving
squall line to the Atlantic coastline.

DISCUSSION...A progressive squall line, with 18 dBZ echo tops
occasionally exceeding 25 kft, continues to pose a damaging wind
threat across portions of southern New England. Numerous
damaging/measured severe gusts have been noted farther west across
southeast New York into New Jersey over the past couple of hours.
Strong low-level Warm air advection continues ahead of the squall,
fostering up to 250 J/kg MUCAPE (mainly within the 850-500 mb
layer), as shown by the latest Mesoanalysis and RAP forecast
soundings. Though buoyancy is mediocre, 50+ kt 925-850 mb wind
fields are in place, and any downward momentum transport that occurs
with the more pronounced downdrafts will support damaging gusts. The
squall is expected to maintain intensity while on land, and is
expected to move out into the Atlantic over the next 2-3 hours.

..Squitieri/Thompson.. 11/16/2020

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

ATTN...WFO...GYX...BOX...OKX...ALY...

LAT...LON   40457391 41437333 42277328 42777309 42847214 42867121
            42807071 42487036 41986994 41677008 41337048 40747197
            40457391 

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SPC MD 1804

MD 1804 CONCERNING SEVERE THUNDERSTORM WATCH 511… FOR FAR EASTERN PENNSYLVANIA…EASTERN MARYLAND…DELAWARE…NEW JERSEY

MD 1804 Image


Mesoscale Discussion 1804
NWS Storm Prediction Center Norman OK
0552 PM CST Sun Nov 15 2020

Areas affected...far eastern Pennsylvania...eastern
Maryland...Delaware...New Jersey

Concerning...Severe Thunderstorm Watch 511...

Valid 152352Z - 160145Z

The severe weather threat for Severe Thunderstorm Watch 511
continues.

SUMMARY...The threat for damaging gusts continues across Severe
Thunderstorm Watch 0511. Damaging gusts will be primarily associated
with a line of storms.

DISCUSSION...A low-topped squall line is currently moving across
eastern PA and northeast MD, with a history of at least scattered
wind damage from Cumberland to Lebanon and Lancaster Counties in PA,
down to Frederick County MD. Storm tops barely reach 25 kft, and the
anticipated line is expected to continue in an ambient thermodynamic
environment characterized by surface temperatures exceeding 60F and
very marginal buoyancy (with the latest RAP forecast soundings
showing 100-150 J/kg MUCAPE, mainly within the 850-600 mb layer).
Despite the weak, elevated instability, very strong forcing for
ascent and intense low-level wind fields suggest that any downward
momentum transport would support damaging gusts with the more mature
segments of the squall. The damaging wind threat is expected to
continue until the squall moves offshore, which will likely be
within the next 2.5-3.5 hours.

..Squitieri/Thompson.. 11/15/2020

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

ATTN...WFO...OKX...PHI...BGM...AKQ...CTP...LWX...

LAT...LON   38617500 38537632 38687733 38917813 39707706 40667612
            41397569 41487488 41367427 40987403 40507387 39787390
            39397419 38937458 38617500 

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SPC Nov 2, 2020 0830 UTC Day 3 Severe Thunderstorm Outlook

SPC 0830Z Day 3 Outlook

Day 3 Outlook Image

Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
1232 AM CST Mon Nov 02 2020

Valid 041200Z - 051200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe thunderstorms are not forecast across the contiguous United
States on Wednesday.

...Synopsis...
A low-amplitude upper-air pattern is forecast across the Lower 48 on
Wednesday.  A powerful upper jet is forecast to nose into the
Pacific Northwest on Wednesday.  Showers and isolated convective
showers are likely for coastal WA into the northern Cascades.  A few
lightning flashes may occur with the deeper convective showers. 
Elsewhere, generally dry/stable conditions will prevail across much
of the CONUS and preclude thunderstorm development.  The exception
may be far south FL where a couple of showers/thunderstorms could
develop during the day.

..Smith.. 11/02/2020

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