MD 0239 CONCERNING HEAVY SNOW FOR SOUTH DAKOTA


Mesoscale Discussion 0239
NWS Storm Prediction Center Norman OK
0835 PM CDT Sat Mar 14 2026

Areas affected...South Dakota

Concerning...Heavy snow 

Valid 150135Z - 150630Z

SUMMARY...Bands of moderate to heavy snow are expected to develop
across central to northeast South Dakota in the coming hours.
Snowfall rates upwards of 1 inch/hour appear likely around/after 04
UTC.

DISCUSSION...Steady surface pressure falls are noted across the High
Plains as a cyclone continues to intensify over NE. Concurrently,
925-850 mb frontogenesis is beginning to increase along the NE/SD
border as the warm-frontal baroclinic zone of the developing cyclone
becomes more focused. Additionally, 00z RAOBS and recent VWP
observations along the MO River Valley/eastern Plains are sampling
strong warm advection from the surface to 2-3 km AGL. The
combination of strengthening frontogenesis within a more broad zone
of isentropic upglide should result in the emergence of at least
transient precipitation bands across SD in the coming hours.
Evidence of this banding is already noted in regional reflectivity
data to the east of Rapid City, SD and south of Aberdeen, SD. 

With time, ascent within the left-exit region of the approaching
upper jet along with strengthening frontogenesis near 700 mb should
promote more persistent banding and increased ascent through the
dendritic growth zone. The result will be a higher probability for
consistent snowfall rates of 1 inch/hour (possibly higher in
localized areas) under the heavier bands. Based on latest guidance,
the onset of 1+ inch/hour rates may be as early as 02 UTC, but will
become more likely after 04 UTC across central to northeast SD.

..Moore.. 03/15/2026

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

ATTN...WFO...MPX...FSD...ABR...UNR...

LAT...LON   44409659 43540161 43490227 43540268 43720291 44110296
            44400284 44690225 45739814 45809760 45839696 45749662
            45559644 45289634 44679626 44409659

MD 0238 CONCERNING SNOW SQUALL FOR CENTRAL TO NORTHERN WYOMING


Mesoscale Discussion 0238
NWS Storm Prediction Center Norman OK
0743 PM CDT Sat Mar 14 2026

Areas affected...Central to northern Wyoming

Concerning...Snow Squall 

Valid 150043Z - 150445Z

SUMMARY...Rapidly falling temperatures, strong winds, and moderate
snowfall behind a sharp cold front are yielding brief
blizzard/snow-squall conditions across north-central Wyoming. These
conditions may persist and spread into central and eastern Wyoming
over the next few hours.

DISCUSSION...Recent radar mosaics show a cold front rapidly pushing
southward to the west of the Big Horn mountains in north-central WY.
Surface observations behind the front have reported temperatures
falling from the low 50s and upper 40s to below freezing within an
hour. Concurrently, strong low-level cold advection (coupled with
strong background gradient winds) is yielding frequent post-frontal
wind gusts of 30-50 mph. This combination of rapidly falling
temperatures, strong wind gusts, and the development of light to
moderate snow showers within the frontal zone is yielding periods of
visibility reductions between 1/2 to 1/4 mile based on regional
ASOS/AWOS reports and web cams. 

The cold front is expected to continue pushing south/southeast over
the next several hours as a cyclone continues to intensify to the
east over the High Plains. Light to moderate snow showers will also
spread to the southeast, which may result in a rapid onset of
flash-freeze conditions and sudden visibility reductions under the
heavier snow showers across central to east-central WY where
temperatures are currently above freezing.

..Moore.. 03/15/2026

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

ATTN...WFO...UNR...CYS...BYZ...RIW...

LAT...LON   45210878 45230814 45140781 43940477 43640444 43270442
            42850457 42630489 42470530 42250587 42190655 42250729
            42480785 42680832 42950870 43320906 44170971 44520984
            44900976 45140936 45210878

SPC 0100Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0740 PM CDT Sat Mar 14 2026

Valid 150100Z - 151200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS BY LATE TONIGHT
ACROSS PARTS OF CENTRAL AND EASTERN IOWA...

...SUMMARY...
A couple of strong thunderstorms capable of producing small to
marginally severe hail are possible overnight across parts of
central and eastern Iowa.

...01Z Update...
The categorical thunderstorm area across the Midwest has been
shifted southward a bit to account for the current position of the
low-level baroclinic zone, and its motion downstream of a surface
cyclone overnight.  The center of the cyclone is forecast to migrate
from eastern Colorado into central Kansas through late this evening,
before reforming northeastward toward the St. Joseph MO vicinity by
early Sunday.  Latest Rapid Refresh forecast soundings indicate that
moisture return to the immediate cool side of the developing warm
frontal zone may contribute to 500-1000 J/kg of most unstable CAPE,
near the nose of an intensifying south-southwesterly low-level jet
(including 50-70 kt around 850 mb) across the southern Great Plains
through lower Missouri Valley by 15/09-12Z.

Strongest thunderstorm development seems likely to focus along a
tightening mid-level thermal gradient (centered around 700 mb) to
the north of the Missouri/Iowa state border vicinity, as warming
(and capping) elevated mixed-layer air advects northeast of the
central Great Plains through lower Missouri Valley.  Given the
generally cool overall profiles, storms may, at least initially,
become capable of producing small to marginally severe hail, before
this risk perhaps diminishes as convection becomes more widespread.

..Kerr.. 03/15/2026