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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from SPC Convective Outlooks http://bit.ly/1Mw5lDA

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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from SPC Mesoscale Discussions http://bit.ly/2OZw1pz

Blizzard Warning issued November 25 at 2:57PM CST until November 25 at 6:00PM CST by NWS

…Blizzard Gradually Winding Down but Roads Remain Dangerous… .Snow is gradually coming to an end from west to east across the area; however, roads will remain treacherous into the overnight hours tonight. Ground blizzard conditions are being reported in areas where the snow has ended due to winds of 35 to 45 mph blowing around the fresh snowpack. Total snow accumulations have

Blizzard Warning issued November 25 at 11:26AM CST until November 25 at 6:00PM CST by NWS

…Blizzard Impacting the Region Today… .A dangerous blizzard is impacting the region today with whiteout conditions being reported from Concordia to Topeka as of late morning. Multiple car accidents and road closures are being reported with up to four foot snow drifts. Total snowfall amounts of 6 to 12 inches will be likely for areas north of a line from

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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from SPC Mesoscale Discussions http://bit.ly/1IzDtQu

Blizzard Warning issued November 25 at 9:48AM CST until November 25 at 6:00PM CST by NWS

…Blizzard Impacting the Region Today… .A potent storm is tracking through the region today. Moderate to heavy snow along with blizzard condition are being reported at many areas as of mid-morning. Snowfall rates of over an inch per hour will be possible at times. Total snowfall amounts of 6 to 12 inches will be likely for areas north of a line from Emporia to

Blizzard Warning issued November 25 at 6:33AM CST until November 25 at 6:00PM CST by NWS

…Blizzard on Track to Impact the Region Today… .A potent storm will track through the region today, spreading into north-central Kansas within the next few hours and the rest of northeast and east central Kansas through midday. Rain early on will quickly change over to snow with snowfall rates of over an inch per hour possible at times. Total snowfall amounts of

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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from SPC Mesoscale Discussions http://bit.ly/2QgK4f6

Blizzard Warning issued November 25 at 2:22AM CST until November 25 at 6:00PM CST by NWS

…Blizzard on Track to Impact the Region Today… .A potent storm will track through the region today, spreading into north-central Kansas within the next few hours and the rest of northeast and east central Kansas through midday. Rain early on will quickly change over to snow with snowfall rates of over an inch per hour possible at times. Total snowfall amounts of 6 to