RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Sun Mar 15 04:57:02 UTC 2026.
MD 0240 CONCERNING HEAVY SNOW FOR FAR NORTHWEST IOWA...SOUTHERN MINNESOTA...AND CENTRAL WISCONSIN
Mesoscale Discussion 0240
NWS Storm Prediction Center Norman OK
1155 PM CDT Sat Mar 14 2026
Areas affected...Far northwest Iowa...southern Minnesota...and
central Wisconsin
Concerning...Heavy snow
Valid 150455Z - 151000Z
SUMMARY...Heavy snow banding will become more prominent in the
coming hours across extreme northwest Iowa, southern Minnesota, and
into central Wisconsin. Snowfall rates will likely exceed 2 inches
per hour within a narrow band across the region.
DISCUSSION...An intensifying cyclone is apparent in surface
observations over the central Plains as a prominent upper-level jet
continues to push southeast. Recent VWP observations across the
eastern Plains have shown a pronounced increase in low-level winds
(upwards of 50-60 knots at 1 km AGL) within the developing warm
conveyor belt of the emerging cyclone. Concurrently, an increase in
precipitation is noted from southwest NE into southeast SD as the
strengthening low-level winds augment isentropic ascent as well as
low to mid-level frontogenesis.
In the coming hours, strong isentropic ascent and more focused lift
within the frontogenetical circulation between 850-700 mb will shift
east/northeast into southern MN and central WI as the surface
cyclone begins to migrate east/northeast. Ascent through a deep
layer, including through a somewhat shallow dendritic growth zone,
will support a broad swath of heavy snowfall rates in excess of 1
inch/hour.
A combination of focused ascent within a frontogenetical 700 mb
deformation zone and periodic convective augmentation (8.8 C/km
mid-level lapse rates were noted in an upstream 00z OAX sounding and
should be advecting into the southern flank of the deformation zone)
will likely result in a narrow corridor of snowfall rates between
2-3 inches/hour. Based on a consensus of recent guidance, this band
will most likely emerge across southern MN into central WI during
the 07-11 UTC time frame and will likely persist well into the
mid-morning hours.
..Moore.. 03/15/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MQT...GRB...DLH...ARX...MPX...DMX...FSD...
LAT...LON 45338876 45318807 45178757 45028729 44778720 44338741
44068759 44078813 44149025 44169073 44049130 43519322
43169443 43079499 43159547 43409578 43699585 43969558
44469481 44809414 45149324 45339221 45389097 45338876
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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
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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
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