LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0111 AM CDT Tue Jul 29 2025
Valid 291200Z - 301200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM SOUTHERN
MONTANA ACROSS EASTERN WYOMING...NEBRASKA...AND INTO WESTERN IOWA...
...SUMMARY...
Severe thunderstorms are expected from southern Montana into the
central High Plains, and across much of Nebraska and western Iowa.
Areas of damaging winds will be possible, with hail most likely over
western areas.
...Much of NE into IA...
A cold front is likely to extend from northeast Co into northern NE
and IA during the afternoon, while low pressure develops over
western KS. Winds aloft will be relatively weak at these latitudes,
only averaging near 15-20 kt. Winds below 500 mb will also be
relatively weak, except for within the deeply mixed boundary layer
with gusty south winds.
Indications are that thunderstorms will develop by late afternoon
across eastern CO and western NE, with increasing coverage and vigor
near the stalled front across NE and into northern IA. Models
indicate numerous storms during the evening, with a general eastward
propagation. Given such weak winds below 500 mb, it appears
widespread and potentially shorter lived convection will be
possible. However, an eventual aggregation into an MCS is expected,
which could yield greater overall coverage of strong to severe
gusts. Isolated significant gusts cannot be ruled out as storms move
into the strongly heated air mass/deeply mixed boundary layer.
...MT into WY...
High pressure will exist over southern Canada with northeast surface
winds across much of the northern Plains. Dewpoints in the 50s to
near 60 F will remain with in this air mass from eastern MT into WY,
and daytime heating will yield MUCAPE over 2000 J/kg by afternoon.
Cool temperatures aloft will exist in the mid and upper levels,
along with 20-30 kt westerlies. Storms will form over the higher
terrain during the late afternoon, aided by upslope flow. Given the
backed low-level wind fields, sufficient shear will favor large
hail, perhaps into the 1.75 to 2.00" range in the strongest cells.
Locally damaging gusts will also be likely.
..Jewell/Squitieri.. 07/29/2025
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