SPC Center Public Severe Weather Outlook (PWO)

Public Severe Weather Outlook

PWO Image

PUBLIC SEVERE WEATHER OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0255 PM CST FRI NOV 30 2018

...Severe thunderstorms expected over parts of the ArkLaTex and
vicinity this evening and overnight...

* LOCATIONS...
  Western and central Arkansas
  Southeastern Oklahoma
  Northeastern Texas
  Northwestern Louisiana

* HAZARDS...
  A few intense tornadoes
  Scattered damaging winds
  Scattered large hail

* SUMMARY...
  Severe thunderstorms are forecast from parts of the southern
  Plains to the lower Mississippi Valley this afternoon into
  tonight, with a risk for tornadoes, damaging winds, and large
  hail. Some of the tornadoes may be strong this evening and
  overnight.

Preparedness actions...

Tornadoes at night can be particularly dangerous because they 
are usually fast-moving and difficult to see. Stay tuned to
NOAA Weather Radio, weather.gov, or other media for watches and
warnings. A tornado watch means that conditions are favorable
for tornadoes to form during the next several hours. If a tornado
warning is issued for your area, move to a place of safety,
ideally in a basement or interior room on the lowest floor of a
sturdy building.

&&

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SPC MD 1664

MD 1664 CONCERNING BLIZZARD FOR NORTHERN IL AND ADJACENT PORTIONS OF EASTERN IA/SOUTHERN WI

MD 1664 Image


Mesoscale Discussion 1664
NWS Storm Prediction Center Norman OK
0654 PM CST Sun Nov 25 2018

Areas affected...Northern IL and adjacent portions of Eastern
IA/Southern WI

Concerning...Blizzard 

Valid 260054Z - 260700Z

SUMMARY...Heavy snow will spread into a larger portion of northern
IL this evening. As stronger winds move in from the west, blizzard
conditions will expand later tonight across the region.

DISCUSSION...00Z surface analysis depicts a 993 mb surface cyclone
just northeast of St. Louis. To the north and northwest of the low,
heavy snow is ongoing from northeast MO into northwest IL, with
stronger winds in the northwestern quadrant of the cyclone producing
blizzard conditions. Dual pol products from KILX/KLOT and recent
surface obs and mPing reports indicate that the rain/snow line is
moving eastward across northern IL, and this trend is expected to
continue as backing surface winds result in increasing low-level
cold advection to the north and northwest of the east-northeastward
moving surface low. Snow should continue spreading into most of the
Chicagoland area between now and 02Z, though areas in the immediate
vicinity of Lake Michigan may see a longer period of mixed
precipitation as northeasterly winds off of the lake maintain a
slightly warmer near-surface layer. 

Substantial convection has been noted near the surface low moving
into southern IL, with a convective character to the precip (and
some thundersnow reports) also noted within cooling cloud tops
across northern IL. Strong low/midlevel frontogenesis will continue
to favor moderate-to-heavy snow to the north of the midlevel low,
with some convective enhancement possible just north of the midlevel
dry slot, where relatively steep lapse rates (in excess of 7 C/km as
noted on ILX/DVN 00Z soundings) will be maintained. Snow rates of
1-3 inches per hour are expected within the primary snow band, which
should shift gradually eastward into northeast IL by late tonight. 

Strong winds (gusts in excess of 40 kt) are resulting in ongoing
blizzard conditions from northeast MO into northwest IL. These
stronger winds will expand eastward with time tonight in conjunction
with the movement of the surface low, resulting in an expansion of
blizzard conditions into northeast IL and perhaps far southeast WI
after 03Z tonight.

..Dean.. 11/26/2018

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

ATTN...WFO...LOT...ILX...MKX...DVN...

LAT...LON   41349111 42049035 42668896 42768779 42008763 41628760
            40978822 40948870 41228944 41369046 41349111 

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SPC MD 1659

MD 1659 CONCERNING BLIZZARD FOR CENTRAL/EASTERN KANSAS…NORTHWEST MISSOURI…FAR SOUTHEAST NEBRASKA…SOUTHWEST IOWA

MD 1659 Image


Mesoscale Discussion 1659
NWS Storm Prediction Center Norman OK
1059 AM CST Sun Nov 25 2018

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

Concerning...Blizzard 

Valid 251659Z - 252200Z

SUMMARY...1-2 inch/hr snowfall rates expected to continue for
several more hours across the area, with occasional blizzard
conditions likely northwest of the surface low.

DISCUSSION...A 998 mb surface low, currently located across
southwest Missouri, is expected to continue moving northeast in
tandem with a pronounced upper-level shortwave trough. The
upper-level trough will continue to deepen throughout the afternoon,
with 500-300 mb relative wind maxima expected to traverse the base
of the trough this afternoon. As a result, large scale ascent is
expected to increase across the area, where strong 925-700 mb WAA
and moisture advection ahead and to the north of the surface low are
currently underway. 

Increasing divergence aloft associated with the approaching
aforementioned upper-level wind maxima will encourage further
deepening of the surface low, with increases in surface wind speeds
likely. Blizzard conditions have already been reported across
several portions of central/northeast Kansas into far southeast
Nebraska, and these conditions are expected to continue across much
of the outlined area as the low continues eastward. Areas roughly
from Washington to Kingman County Kansas westward may continue to
experience near white-out conditions for a few more hours, but the
threat is expected to clear as snow moves out of the area. 

Otherwise, 1-2 inch/hr snowfall rates should pivot eastward across
far northeast Kansas into northwest Missouri and southwest Iowa,
along the axis of a moisture conveyer belt, where low-level warm
air/moisture advection should continue to saturate the
dentritic-growth layer.

..Squitieri.. 11/25/2018

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

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

LAT...LON   37389637 37379819 37539933 39149858 40259698 40729631
            41119438 41399290 41009233 40309223 39119280 38099510
            37389637 

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SPC MD 1658

MD 1658 CONCERNING HEAVY SNOW FOR CENTRAL…NORTH-CENTRAL AND NORTHEAST KS…SOUTHEAST NE…SOUTHWEST IA…AND NORTHWEST MO

MD 1658 Image


Mesoscale Discussion 1658
NWS Storm Prediction Center Norman OK
0354 AM CST Sun Nov 25 2018

Areas affected...Central...north-central and northeast
KS...southeast NE...southwest IA...and northwest MO

Concerning...Heavy snow 

Valid 250954Z - 251600Z

SUMMARY...Snowfall rates up to 1-2 inches per hour will increase
from west to east during the late overnight through this morning. 
In addition to heavy snow, strengthening northerly winds through the
morning will produce a blizzard with reduced visibilities in
whiteout conditions.

DISCUSSION...Short-term guidance remains consistent with the
forecast for a vigorous shortwave trough, now located over eastern
CO, to emerge eastward across KS overnight, with deepening of this
system between 12-18Z as it reaches eastern KS/western MO by late
morning.  Trends in mosaic radar imagery showed a band of
precipitation had developed from north-central KS to southeast NE. 
This corridor in the northern part of the discussion area is
expected to be the first southwest-northeast oriented zone to change
to snow and increase in rates as surface temperatures fall through
the lower 30s to upper 20s F by 11-12Z.  This same trend with snow
developing across the rest of the discussion area after daybreak
from central to northeast KS and far northwest MO to southwest IA
will occur as the surface low shifts east-northeast into MO.  This
will allow low-level winds on its north-northwest periphery to back
to northerly and strengthen, ushering in colder temperatures, and
supporting a high likelihood for reduced visibilities in whiteout
conditions.

Meanwhile, an increase in upward vertical motion through the
dendritic-growth zone per forecast soundings is expected as, 1) the
shortwave trough deepens with eastward progression and 2) within the
exit region of a strengthening 500-mb 100-kt jet spreading across
northeast KS/northwest MO this morning.  This factor which is
expected to become stronger by 15-18Z suggests snowfall rates could
be up to 2 inches per hour, generally north of a line from KSLN to
KSTJ to 25 S KLWD, while the initial aforementioned band of snow
could have rates up to 1 inch per hour.  Forecast soundings also
indicated weak elevated instability rooted around 600 mb, given the
likelihood of steepening midlevel lapse rates (around 8 C/km) in the
exit region of the midlevel jet.  This could enhance snowfall rates.

..Peters.. 11/25/2018

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

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

LAT...LON   41259537 41359315 41159252 40309380 39249539 38409689
            38239774 38379854 38699916 38909976 39289995 39479979
            40099877 40489775 40979632 41259537 

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SPC MD 1648

MD 1648 CONCERNING WINTER MIXED PRECIPITATION FOR CENTRAL APPALACHIANS…MID ATLANTIC

MD 1648 Image


Mesoscale Discussion 1648
NWS Storm Prediction Center Norman OK
0856 AM CST Thu Nov 15 2018

Areas affected...Central Appalachians...Mid Atlantic

Concerning...Winter mixed precipitation 

Valid 151456Z - 152100Z

SUMMARY...Areas of heavy snow are likely to develop in the higher
elevations of the central Appalachian Mountains this morning. By
afternoon, a mixture of snow and sleet are likely in the lower
elevations from northern Virginia into northern New Jersey. This
corridor may changeover to freezing rain or rain this afternoon.

DISCUSSION...The latest water vapor imagery shows an upper-level low
in the mid Mississippi Valley with southwest mid-level flow over
much of the eastern Seaboard. At the surface, a large area of high
pressure is in place across the Northeast. Surface temperatures are
below freezing in most of the central Appalachians with dewpoints
mostly in the teens. As a large area of precipitation moves across
the central Appalachians this morning, the temperature profile will
support the development of snow.  Areas of heavy snow will be
possible especially in the higher elevations of the central
Appalachian Mountains where 1 inch per hour snowfall rates may
occur.

Surface temperatures from northern Virginia northeastward to
northern Maryland are currently just below freezing. At this time,
light snow is being reported along this corridor. This snow will
likely develop northeastward into southeast Pennsylvania and
northern New Jersey late this morning. As warm advection continues
over the top of the cold airmass late this morning into early
afternoon, a changeover to sleet, freezing rain and rain will be
possible from northern Virginia to northern New Jersey.

..Broyles/Hart.. 11/15/2018

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

ATTN...WFO...OKX...ALY...PHI...BGM...BUF...CTP...LWX...PBZ...
RLX...

LAT...LON   38327873 38517974 39167986 40567961 41717904 42067799
            41907558 41547397 40537401 39307622 38597785 38327873 

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SPC Center Public Severe Weather Outlook (PWO)

Public Severe Weather Outlook

PWO Image

PUBLIC SEVERE WEATHER OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0224 PM CST MON NOV 05 2018

...Severe thunderstorms expected over parts of the ArkLaMiss to the
Tennessee Valley this evening and overnight...

* LOCATIONS...
  Northern Mississippi
  Western and Middle Tennessee
  Northwestern Alabama
  Southeastern Arkansas
  Northeastern Louisiana

* HAZARDS...
  A few intense tornadoes
  Scattered damaging winds

* SUMMARY...
  Severe storms capable of damaging winds and tornadoes are likely
  this evening and overnight across the ArkLaMiss region and
  Tennessee Valley. The severe threat is expected to begin near or
  just after sunset near the Mississippi River and continue
  through the overnight hours into the Tennessee Valley.

Preparedness actions...

Tornadoes at night can be particularly dangerous because they 
are usually fast-moving and difficult to see. Stay tuned to
NOAA Weather Radio, weather.gov, or other media for watches and
warnings. A tornado watch means that conditions are favorable
for tornadoes to form during the next several hours. If a tornado
warning is issued for your area, move to a place of safety,
ideally in a basement or interior room on the lowest floor of a
sturdy building.

&&

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SPC Nov 5, 2018 0700 UTC Day 2 Convective Outlook

SPC 0700Z Day 2 Outlook

Day 2 Outlook Image

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1247 AM CST Mon Nov 05 2018

Valid 061200Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM A PORTION OF
THE SOUTHEAST STATES TO THE MIDDLE ATLANTIC REGION...

...SUMMARY...
A few severe storms with locally strong wind gusts and perhaps a
tornado or two will be possible from a portion of the Southeast
States to the Middle Atlantic region.

...A portion of the Southeast States into Middle Atlantic region...

Surface low will occlude over the Great Lakes Tuesday morning in
association with a northeast-ejecting shortwave trough. Trailing
front will move off the Middle Atlantic seaboard by evening, but
southwest extension of this boundary will stall from southern
portions of the Gulf Coast States into TX. 

Showers and thunderstorms will be ongoing along and just ahead of a
cold front from the OH Valley into a part of the Gulf Coast states
with a modest risk for isolated damaging wind. This activity may
weaken as it crosses the Appalachians due to the very marginal
thermodynamic environment. A strong southerly low-level jet will
transport low-mid 60s F dewpoints into the Middle Atlantic region
contributing to potential for surface-based destabilization with
400-800 J/kg MLCAPE. Redevelopment of low-topped convection with
embedded thunderstorms may occur, especially from central/eastern
Carolinas to VA and eastern PA as the surface layer moistens and
destabilizes during the day. The convection will be embedded within
a strong kinematic environment with wind profiles supportive of
updraft rotation and a few bowing segments. Tendency for the deeper
forcing to shift north, away from the more unstable portion of the
warm sector and the overall weak thermodynamic environment remain
limiting factors, but feel threat is sufficient to maintain the
slight risk for this update.

...MAXIMUM RISK BY HAZARD...
Tornado:   5%     - Slight
Wind:     15%     - Slight
Hail:     <5%     - None

..Dial.. 11/05/2018

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SPC Nov 4, 2018 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
0144 AM CST Sun Nov 04 2018

Valid 061200Z - 071200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM A PORTION OF
THE SOUTHEAST STATES TO THE MIDDLE ATLANTIC REGION...

...SUMMARY...
A few strong to severe storms with locally strong wind gusts and
perhaps a couple of tornadoes will be possible from a portion of the
Southeast States to the Middle Atlantic region.

...A portion of the Southeast States to Middle Atlantic...

Showers and thunderstorms will be ongoing along and just ahead of a
cold front from the OH Valley into the Gulf Coast states with an
ongoing modest risk for isolated damaging wind. Surface low will
shift from the OH Valley into the lower Great Lakes as the attendant
shortwave trough advances northeast. Some of the thunderstorms may
weaken/dissipate as they cross the Appalachians. Redevelopment may
occur, especially from the central/eastern Carolinas into the
eastern Middle Atlantic during the afternoon where greater
destabilization is possible in association with northward advection
of richer low-level moisture. The kinematic environment will support
organized convection along/ahead of the cold front. However,
widespread clouds and weak instability will probably serve as
overall limiting factors for a more robust severe threat.

..Dial.. 11/04/2018

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SPC Center Public Severe Weather Outlook (PWO)

Public Severe Weather Outlook

PWO Image

PUBLIC SEVERE WEATHER OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0310 PM CDT WED OCT 31 2018

...Severe thunderstorms expected over parts of the lower Mississippi
Valley this evening and overnight...

* LOCATIONS...
  Louisiana
  Southern and Central Mississippi
  East Texas

* HAZARDS...
  A few intense tornadoes
  Scattered damaging winds
  Isolated large hail

* SUMMARY...
  The greatest risk for severe thunderstorms, capable of producing
  damaging winds, hail, and tornadoes, exists from southeast Texas
  to the lower Mississippi Valley through tonight.

Preparedness actions...

Tornadoes at night can be particularly dangerous because they 
are usually fast-moving and difficult to see. Stay tuned to
NOAA Weather Radio, weather.gov, or other media for watches and
warnings. A tornado watch means that conditions are favorable
for tornadoes to form during the next several hours. If a tornado
warning is issued for your area, move to a place of safety,
ideally in a basement or interior room on the lowest floor of a
sturdy building.

&&

..Gleason.. 10/31/2018

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SPC MD 1580

MD 1580 CONCERNING TORNADO WATCH 414… FOR PART OF CENTRAL AND EASTERN TX

MD 1580 Image


Mesoscale Discussion 1580
NWS Storm Prediction Center Norman OK
0741 PM CDT Sat Oct 13 2018

Areas affected...Part of central and eastern TX

Concerning...Tornado Watch 414...

Valid 140041Z - 140145Z

The severe weather threat for Tornado Watch 414 continues.

SUMMARY...Local extension (both spatial and temporal) may be needed
for the southwest part of WW 414 and extending southward several
counties, as a severe-weather threat persists beyond 01Z, including
the tornado potential.

DISCUSSION...Mosaic radar imagery showed storms continuing to
develop within the the southwest flank of a central and northeast TX
MCS, while GOES-16 IR imagery indicated ongoing cloud-top cooling
across this same area of the MCS.  Although the main band of storms
appears to be located along and near the primary southward-moving
outflow boundary, radar trends also indicated new storms developing
in the warm sector, immediately to the south, from Burleson to
Brazos to Madison Counties.  Objective analyses indicated
surface-based inhibition has been increasing, given time of day
across east TX into LA, though the environment in proximity to the
aforementioned storms remains unstable with surface-based storms.

Given the presence of a moisture-rich environment with moderate
instability and effective bulk shear of 40-45 kt, embedded bowing
structures and low-level rotation/tornado threat should persist
until the surface-based inhibition becomes too strong.

..Peters/Guyer.. 10/14/2018

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

ATTN...WFO...SHV...HGX...FWD...

LAT...LON   30769657 31099580 31579529 31779461 31809422 31299431
            31049470 30689489 30369556 30199614 30159656 30589670
            30769657 

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