SPC Mar 11, 2019 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook

Day 2 Outlook Image

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1256 AM CDT Mon Mar 11 2019

Valid 121200Z - 131200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN PLAINS...

...SUMMARY...
Severe thunderstorms capable of producing isolated damaging winds,
large hail, and perhaps a tornado or two will be possible beginning
mainly late Tuesday afternoon and continuing through the overnight
hours across parts of the southern Plains.

...Synopsis...
A closed upper low over the lower CO River Valley and adjacent Baja
Peninsula will evolve into a negatively tilted shortwave trough as
it ejects east-northeastward across the Southwest and southern
Plains on Tuesday. Strong ascent preceding this shortwave trough
will encourage surface cyclogenesis across the southern/central High
Plains through the day, with a deep surface low eventually
consolidating over southeastern CO. Low-level mass response will
bring at least partially modified Gulf moisture westward and
northward across the southern Plains.

...Southern Plains...
Isolated to perhaps widely scattered elevated thunderstorms posing a
marginal hail threat may be ongoing Tuesday morning across parts of
eastern NM into west TX in a low-level warm air advection regime.
This convection should spread northeastward across the TX/OK
Panhandles and main body of OK through the afternoon. At least some
diurnal heating should occur across the higher terrain of
central/eastern NM into west TX in the wake of this morning
activity. This heating combined with steep mid-level lapse rates
emanating from the higher terrain of northern Mexico and surface
dewpoints in the mid 50s to lower 60s should foster MLCAPE of
500-1000 J/kg across the southern High Plains through peak diurnal
heating.

Convective initiation appears likely by late Tuesday afternoon as a
strong southwesterly mid-level jet attendant to the shortwave trough
overspreads eastern NM and west TX. Effective bulk shear exceeding
50 kt will easily support supercells with mainly an isolated large
hail threat. A Pacific cold front will eventually overtake this
convection Tuesday evening, with upscale growth into squall line
likely. Isolated damaging winds should be the primary threat with
this linear convection as it moves quickly eastward across
central/east TX overnight. A tornado or two also cannot be ruled out
within the line due to the strong low-level shear that will be
present owing to a 45-60+ kt southerly low-level jet. Eventually
this squall line should weaken some as it encounters a less unstable
airmass across east TX late in the period.

There is still considerable uncertainty whether there will be
sufficient low-level moisture return across western/central OK to
support surface-based thunderstorms. Have therefore refrained from
making any substantial changes to the Marginal and Slight risk
delineations across this area.

...MAXIMUM RISK BY HAZARD...
Tornado:   2%     - Marginal
Wind:     15%     - Slight
Hail:     15%     - Slight

..Gleason.. 03/11/2019

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SPC MD 178

MD 0178 CONCERNING TORNADO WATCH 15…16… FOR FAR NORTHEAST MS…NORTHERN AL…MIDDLE TN

MD 0178 Image


Mesoscale Discussion 0178
NWS Storm Prediction Center Norman OK
0720 PM CST Sat Mar 09 2019

Areas affected...Far Northeast MS...Northern AL...Middle TN

Concerning...Tornado Watch 15...16...

Valid 100120Z - 100245Z

The severe weather threat for Tornado Watch 15, 16 continues.

SUMMARY...Potential for isolated damaging wind gusts and/or a brief
tornado will continue across northeast MS, northern AL, and middle
TN for the next hour or two.

DISCUSSION...KGWX radar imagery has shown sporadic and brief
low-level rotation within the supercell now moving through southern
Lowndes county. However, latest scans have shown a trend towards
less low-level inflow/low-level organization with velocity values
decreasing and the previously observed ZDR arc losing definition.
Echo tops have also decreased over the past 30 min or so. Strongest
updraft (based on echo top) appears to be associated with the storm
in Franklin and Cobert counties in far northwest AL. Downstream air
mass from both of these storms suggests a gradual decrease in
intensity as instability wanes. Even so, given the strong low-level
shear, brief low-level organization capable of isolated wind
damaging and or a brief tornado remains possible.

Farther north, the convective line moving across middle TN has shown
modest intensification, particularly over the last 30 min or so.
Downstream thermodynamic environment is characterized by
temperatures in the 60s, dewpoints in the limited instability. Even
so, very strong low-level shear (sampled well by the 00Z BNA
sounding) could still support instances of damaging wind gusts and
perhaps a brief tornado before the line moves into cooler, more
stable air north of the warm front.

..Mosier.. 03/10/2019

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

ATTN...WFO...OHX...BMX...HUN...MEG...JAN...

LAT...LON   33438845 34048830 34668788 35608684 36578600 36268543
            34718643 33818712 33158788 33138822 33438845 

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SPC MD 163

MD 0163 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR PARTS OF EASTERN OKLAHOMA…SOUTHEAST KANSAS…THE SOUTHWESTERN QUARTER OF MISSOURI…AND THE NORTHWEST QUARTER OF ARKANSAS

MD 0163 Image


Mesoscale Discussion 0163
NWS Storm Prediction Center Norman OK
0158 AM CST Sat Mar 09 2019

Areas affected...parts of eastern Oklahoma...southeast Kansas...the
southwestern quarter of Missouri...and the northwest quarter of
Arkansas

Concerning...Severe potential...Watch possible 

Valid 090758Z - 090930Z

Probability of Watch Issuance...60 percent

SUMMARY...Risk for hail emanating from elevated storms will likely
increase over the next 1-2 hours, possibly warranting WW issuance.

DISCUSSION...Latest surface analysis shows a warm front from
extending from east-central Oklahoma east-southeast across
central/southern Arkansas.  North of the front, a very stable
boundary layer is indicated, with temperatures and dewpoints
generally in the 40s.

Water vapor imagery depicts the intense trough crossing the southern
Rockies at this time, which is gradually acquiring negative tilt,
and a broad zone of increasing ascent is also indicated downstream
of the axis, west of -- and spreading into -- the discussion area. 

Model soundings across the region, and special 06Z ROABs, both
indicate steep lapse rates above 850mb, atop the low-level stable
air, with CAPE becoming increasingly sufficient for stout, elevated
updrafts as additional moistening/theta-e advection aloft occurs in
advance of the advancing trough.  With flow aloft also increasing
ahead of this feature, shear will support rotating updrafts where
CAPE becomes sufficient for updraft longevity.  Given these factors,
risk for large hail should steadily increase over the next couple of
hours -- possibly warranting WW issuance.

..Goss/Edwards.. 03/09/2019

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

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

LAT...LON   35039624 35209682 35979683 37719592 38309552 38559367
            38269191 36219211 34899295 35039624 

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SPC MD 139

MD 0139 CONCERNING HEAVY SNOW FOR CENTRAL AND EASTERN KS

MD 0139 Image


Mesoscale Discussion 0139
NWS Storm Prediction Center Norman OK
0123 AM CST Sun Mar 03 2019

Areas affected...central and eastern KS

Concerning...Heavy snow 

Valid 030723Z - 031130Z

SUMMARY...Periods of moderate to heavy snow with rates around 1 inch
per hour are expected across parts of central into eastern KS
through the early morning hours. Gusty winds also will lead to
blowing and drifting snow and further reducing visibility.

DISCUSSION...Moderate to heavy snow has been tracking east from
western in central KS over the last few hours. Some heavier bands
have been noted over southwest into south-central KS the last 1-2
hours in particular. This area of snow is associated with broad
ascent as a shortwave trough ejects from eastern CO into the central
Plains in otherwise low-amplitude westerly flow regime. 07z
mesoanalysis indicates the dendritic growth zone thickness ranges
from about 2-3 kft with a nearly saturated layer extending from near
the surface through the dendritic growth zone. This will aid in
periods of heavy snow, approaching 1 inch per hour at times, as
stronger forcing shifts eastward in conjunction with modest
frontogenesis around 700mb. Some areas across central KS could see
brief periods of heavier snow rates around 1.5-2 inches per hour. In
addition to periods of moderate to heavy snow, north-northeast winds
around 15 mph with gusts to 25 mph will create areas of blowing and
drifting snow and further reduce visibility into the early morning
hours.

..Leitman.. 03/03/2019

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

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

LAT...LON   38189912 38849918 39299895 39679807 39729728 39629625
            38989518 38469508 37819562 37389629 37169692 37009792
            37079832 37229876 37529904 37629905 38189912 

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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
0650 AM CST SAT FEB 23 2019

...Severe thunderstorms expected over parts of the Parts of the
Tennessee and lower Mississippi Valleys this afternoon and
evening...

* LOCATIONS...
  Northern Mississippi
  Southern parts of western and middle Tennessee
  Northwestern Alabama

* HAZARDS...
  Several tornadoes, a few intense
  Scattered damaging winds
  Isolated large hail

* SUMMARY...
  A few strong tornadoes, as well as damaging winds and isolated
  large hail, will be possible this afternoon and evening
  primarily across parts of Mississippi, Alabama, and Tennessee.

Preparedness actions...

Review your severe weather safety procedures for the possibility
of dangerous weather today. 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.

&&

..Thompson.. 02/23/2019

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SPC MD 105

MD 0105 CONCERNING HEAVY SNOW FOR EAST NE…SOUTHWEST INTO CENTRAL IA…NORTHERN MO

MD 0105 Image


Mesoscale Discussion 0105
NWS Storm Prediction Center Norman OK
0726 PM CST Sat Feb 16 2019

Areas affected...East NE...southwest into Central IA...northern MO

Concerning...Heavy snow 

Valid 170126Z - 170630Z

SUMMARY...Heavy snow expected over the next several hours. Up to 1
inch/hr snowfall rates will be possible in some spots.

DISCUSSION...A mid-level shortwave trough and associated 850 mb low
are currently established in the Central Plains, preceded by
deep-layer moisture advection and low-level WAA across the
Mid-Missouri Valley. At the moment, the thermodynamic profile of the
troposphere across the discussion area can be characterized by
near-saturated to saturated conditions in the sfc-700 mb layer (per
00Z TOP observed soundings and recent RAP point-forecast soundings),
with relatively strong WAA advection present in the 925-700 mb
layer, amidst below-freezing temperatures throughout the column. 

The -12 to -17C layer, favorable for dendritic growth, is nearly
saturated and quite deep across the discussion area (per latest
mesoscale analysis) and is expected to remain so for several more
hours, as the aforementioned WAA and large scale ascent continues to
impinge on the region. As such, conditions support at least
occasionally heavy snow throughout the evening hours, with a few
spots potentially seeing accumulation rates of up to 1 inch/hr, as
supported by the latest high resolution model guidance.

..Squitieri.. 02/17/2019

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

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

LAT...LON   41379175 40209199 39589309 39359470 39789599 40169718
            40619810 41599783 42209666 42349506 42249410 41759268
            41379175 

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SPC MD 79

MD 0079 CONCERNING WINTER MIXED PRECIPITATION FOR PORTIONS OF NORTHERN OKLAHOMA…SOUTHERN/EASTERN KANSAS…AND WESTERN MISSOURI

MD 0079 Image


Mesoscale Discussion 0079
NWS Storm Prediction Center Norman OK
0751 PM CST Wed Feb 06 2019

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

Concerning...Winter mixed precipitation 

Valid 070151Z - 070745Z

SUMMARY...Winter mixed precipitation will develop across portions of
northern Oklahoma, southern/eastern Kansas, and western Missouri
tonight. Heavy freezing rain/sleet are possible.

DISCUSSION...A strong upper-level trough is moving onto the Plains
this evening and a strengthening low-level jet is increasing
warm-air advection above a cold air mass across Kansas/Oklahoma. A
couple of elevated multi-cellular convective clusters are moving
along the northern edge of the low-level jet/warm-air advection.
Mid-level lapse rates are steepening as cold air aloft spreads
eastward, which will increase coverage of storms/showers in the next
couple of hours across portions of northern Oklahoma,
southern/eastern Kansas, and western Missouri. The warm-nose should
remain in place tonight within the MCD area at 850-700 mb with below
freezing surface temperatures resulting in freezing rain and sleet.
MUCAPE of 250-1000 J/kg and mixed-phase clouds should result in CG
lightning and could produce locally heavy freezing rain/sleet.
Generally, precipitation rates will be 0.05-0.15" per hour with
widespread ice accumulation expected. In areas with stronger surface
winds, ice accretion will be more efficient and sleet accumulation
is also possible within convective bands/showers.

..Nauslar/Edwards.. 02/07/2019

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

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

LAT...LON   36889576 36729640 36559698 36309778 36239828 36179871
            36259904 36469929 36779937 37079938 37289936 37759901
            38729772 39409672 39959585 40029518 39979472 39739418
            39399362 39059332 38739318 38399326 38039369 37979382
            37619430 37329469 37129505 37029535 36889576 

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SPC MD 65

MD 0065 CONCERNING HEAVY SNOW FOR SIERRA MOUNTAINS

MD 0065 Image


Mesoscale Discussion 0065
NWS Storm Prediction Center Norman OK
0318 PM CST Sun Feb 03 2019

Areas affected...Sierra Mountains

Concerning...Heavy snow 

Valid 032118Z - 040315Z

SUMMARY...Heavy snow, with rates of 1 inch per hour and locally
exceeding 3 inches per hour at times -- especially at higher
elevations, will develop into the evening.

DISCUSSION...Strong, moist flow into a cooling troposphere is
supporting efficient snow production across much of the Sierra
Mountains. This large-scale pattern is expected to remain in place
through the evening as strong deep-layer ascent increases in
response to the next cyclone moving southward along the California
coast. Increasing ascent is already evident on water-vapor and
infrared satellite imagery, as well as in radar imagery, across the
Sacramento Valley as cloud tops have cooled and banded/cellular
echos have developed. As the lower troposphere cools, snow levels
fall, and these cellular features move into the Sierras, snowfall
rates briefly approaching 3 inches per hour may occur at elevations
as low as 6000-7000 feet. Strong winds will accompany this heavy
snow resulting in blizzard conditions at times.

Although snow will continue well into the overnight snowfall rates
may relax a bit overnight before picking up in intensity again
tomorrow ahead of the next short-wave trough embedded within the
larger-scale trough.

..Marsh.. 02/03/2019

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

ATTN...WFO...REV...HNX...STO...

LAT...LON   37431950 38332036 39532113 39712048 38901987 37781883
            37431950 

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SPC MD 61

MD 0061 CONCERNING HEAVY SNOW FOR EASTERN PENNSYLVANIA INTO SOUTHEASTERN NEW YORK…NEW JERSEY AND ADJACENT PORTIONS OF THE NORTHERN MID ATLANTIC AND SOUTHERN NEW ENGLAND

MD 0061 Image


Mesoscale Discussion 0061
NWS Storm Prediction Center Norman OK
1010 AM CST Wed Jan 30 2019

Areas affected...Eastern Pennsylvania into southeastern New
York...New Jersey and adjacent portions of the northern Mid Atlantic
and southern New England

Concerning...Heavy snow 

Valid 301610Z - 302015Z

SUMMARY...A brief burst of heavy snow, strong wind gusts and reduced
visibilities may accompany the passage of a cold front this
afternoon, perhaps affecting much of the Greater New York City
metropolitan area during the 2-4 PM EST time frame.

DISCUSSION...The leading edge of stronger lower tropospheric cooling
(centered around 850 mb...where temps falling from roughly -15 to
-30C), now surging east of the Allegheny Mountains, is forecast to
continue eastward into western New England and the northern Mid
Atlantic region through 20-22Z.  Model forecast soundings suggest
that is being accompanied by increasing boundary layer
destabilization supportive of deepening convective development, with
tops likely to approach 10,000+ feet, particularly across parts of
eastern Pennsylvania and central/northern New Jersey into
southeastern New York late this afternoon.

Frontogenetic forcing appears to be supporting a narrow, but
sustained, evolving band of convection.  This is likely being aided
by lift within the exit region of a 110-130 kt cyclonic 500 mb jet
streak forecast to nose across the northern Mid Atlantic, lower
Hudson Valley, and southern New England by late this afternoon.

Given the cold thermodynamic profiles, including a layer supportive
of large dendritic ice crystal growth, guidance is suggestive that
the convection may be accompanied by a burst of heavy snow rates
around or in excess of 1 inch per hour.  It appears this may last
only 15 to 30 minutes at any one location, but it may be accompanied
by fairly strong surface wind gusts in excess of 30 kts, and sharply
reduced visibilities.

..Kerr.. 01/30/2019

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

ATTN...WFO...BOX...BTV...OKX...ALY...PHI...BGM...CTP...LWX...

LAT...LON   40187685 41577615 42637568 43557345 42817280 42297262
            41427249 40227382 39647578 39647711 40187685 

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SPC MD 43

MD 0043 CONCERNING FREEZING RAIN FOR NORTHEAST KS…NORTHWESTERN MO…SOUTHERN IA

MD 0043 Image


Mesoscale Discussion 0043
NWS Storm Prediction Center Norman OK
0120 PM CST Tue Jan 22 2019

Areas affected...northeast KS...northwestern MO...southern IA

Concerning...Freezing rain 

Valid 221920Z - 222245Z

SUMMARY...Freezing rain rates approaching 0.05 inch per hour are
possible beginning early this afternoon and spreading from west to
east from northeast KS into southeast IA.

DISCUSSION...Surface analysis places a cold front from east-central
KS northeast through the Kansas City metro.  Temperatures are
falling into the upper 20s to near 30 degrees F behind the front.  A
mid-level trough located over the central High Plains this afternoon
will continue to pivot east towards the region and large-scale
forcing for ascent will gradually increase in the vicinity of the
frontal zone this afternoon.  Forecast soundings show a warm nose
with temperatures above freezing around 800 mb atop a 1 km deep
layer at or below freezing---indicative of freezing rain as the
favored precipitation type before transitioning to sleet over KS and
MO later this afternoon.  The latest ECMWF guidance suggests
freezing rain rates near 0.05 inch per 3 hours will become
increasingly common by late afternoon.

..Smith.. 01/22/2019

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

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

LAT...LON   38699674 39939603 40939393 41349229 41059149 40619149
            40459228 40339368 39959472 39139568 38609612 38699674 

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