RSS Mesoscale Discussions from Storm Prediction Center

SPC Apr 21, 2019 1630 UTC Day 1 Convective Outlook

SPC 1630Z Day 1 Outlook
      
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1119 AM CDT Sun Apr 21 2019

Valid 211630Z - 221200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE THIS
AFTERNOON INTO EARLY TONIGHT ACROSS PARTS OF THE CENTRAL PLAINS...

...SUMMARY...
Marginally severe hail or wind is possible across parts of the
central Plains this afternoon and evening, mainly from northern
Kansas into Nebraska.

...Central Plains late this afternoon into tonight...
A series of low-amplitude midlevel troughs will eject
east-northeastward from NM/CO to the mid MO Valley, downstream from
an amplifying trough over the lower CO Valley.  Modest low-level
moisture return is underway from the western Gulf of Mexico to the
southern/central Plains.  The moistening will occur beneath a warm
elevated mixed layer, and much of the warm sector will remain capped
through the period.  Strong surface heating/deep mixing and
low-level ascent from near a lee cyclone along the CO/KS border
northeastward along a cold front into NE should support thunderstorm
development this afternoon/evening.  MLCAPE of 500-1000 J/kg with
steep low-level lapse rates and DCAPE greater than 1000 J/kg will
favor high-based, multicell storm clusters capable of producing
isolated severe outflow winds and marginally severe hail late this
afternoon into early tonight.

..Thompson/Squitieri.. 04/21/2019

Read more

SPC Apr 21, 2019 1730 UTC Day 2 Convective Outlook

SPC 1730Z Day 2 Outlook
      
Day 2 Outlook Image
Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1237 PM CDT Sun Apr 21 2019

Valid 221200Z - 231200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE SOUTHERN HIGH PLAINS LATE MONDAY AFTERNOON INTO MONDAY NIGHT....

...SUMMARY...
Widely scattered severe thunderstorms may produce large hail and
isolated wind damage across parts far east-central New Mexico into
the Texas South Plains and southwestern Oklahoma late Monday
afternoon through the overnight hours.

...Synopsis...
A weak upper ridge over the southern Plains will suppress convection
for much of the day due to a strong cap in the 850-700 mb layer. 
Further north, a shortwave trough will migrate eastward across the
Upper Midwest and Great Lakes.  A cold front will extend
southwestward from a surface low over western IA into the OK/TX
Panhandle vicinity early Monday.  As the low and cold front shift
east, an area of thunderstorms will move across IA into southern WI
and northern IL.  This activity is not expected to be severe, but
some small hail and gusty winds are possible. 

The northern section of the cold front will advance eastward into
the mid-MS Valley by Tuesday morning while the southern portions of
the front remains more diffuse, extending from east-central NM into
central OK at the end of the period.  The slow-moving front will be
a focus for thunderstorm develop across the southern High Plains by
late afternoon into the overnight hours when a western upper trough
ejects eastward across the southwestern deserts toward the southern
Rockies. Falling heights and cooling temps aloft will aid in
maintaining modestly steep lapse rates. Weakening of the capping
inversion is forecast by late afternoon/evening as stronger forcing
for ascent and modest moisture advection ahead of the front become
sufficient for development of a few surface-based storms. Modest
effective bulk shear around 25-30 kt will result in loosely
organized clusters/semi-discrete cells which may tend to become
bowing segments as they interact/organize along the surface front.
Damaging wind gusts and large hail will be the main concern with
storms from eastern NM through the Texas South Plains into southwest
OK.

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

..Leitman.. 04/21/2019

Read more