RSS Mesoscale Discussions from Storm Prediction Center
SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1254 AM CDT Wed May 27 2026
Valid 271200Z - 281200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-ATLANTIC...
...SUMMARY...
Thunderstorms with severe wind gusts will be possible today across
parts of the Mid-Atlantic and Ohio Valley. Isolated wind gusts and
hail will also be possible in the western Great Lakes and from the
southern Texas Panhandle into west Texas and far western Oklahoma.
...Mid-Atlantic/Ohio Valley...
An upper-level trough will move southeastward today across the Great
Lakes. Flow ahead of the trough will be westerly over the Ohio
Valley and Mid-Atlantic. At the surface, a cold front will move
southward into the Ohio Valley. South of the front, dewpoints in the
60s F will contribute to pockets of moderate instability by
afternoon. As low-level convergence and instability maximizes near
the front, thunderstorms are expected to form and move
east-southeastward across the Ohio Valley and Mid-Atlantic.
RAP forecast soundings just ahead of the front in northern Virginia
at 21Z have MLCAPE near 1200 J/kg with 0-6 km shear around 40 knots.
This will support organized thunderstorms, potentially in the form
of multiple short severe line segments. During the mid to late
afternoon, low-level lapse rates are forecast to peak near 7.5 C/km,
which will be favorable for a wind-damage threat. Hail will also be
possible within the stronger cores.
...Western Great Lakes...
Northwesterly mid-level flow will be in place across the western
Great Lakes today, as a shortwave trough moves southeastward across
the region. At the surface, a pocket of maximized low-level moisture
will be located over Wisconsin, where MLCAPE is expected to peak in
the 1500 to 2500 J/kg range. Thunderstorms that form during the
afternoon that have access to moderate instability and steep
low-level lapse rates could have potential for isolated wind gusts.
Hail could also occur.
...Southern Texas Panhandle/West Texas/Far Western Oklahoma...
At low-levels, a moist and unstable airmass is forecast to advect
northward across west Texas into the southern Texas Panhandle today.
A zone of low-level convergence will likely develop over the
southern Texas Panhandle, with upslope flow to the north of this
feature. As surface temperatures warm during the day, scattered
thunderstorm development is expected near the convergence zone. RAP
forecast soundings to the south and east of Amarillo at 21Z have
steep low to mid-level lapse rates with large surface
temperature-dewpoint spreads. This may be enough for isolated severe
wind gusts and hail.
..Broyles/Chalmers.. 05/27/2026
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SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1225 AM CDT Wed May 27 2026
Valid 281200Z - 291200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM CENTRAL
OREGON INTO EASTERN WASHINGTON...NORTHERN IDAHO AND NORTHWEST
MONTANA...
...SUMMARY...
Isolated severe storms are possible on Thursday over western
Montana, northern Idaho, and into central Oregon/Washington. A few
damaging gusts or marginal hail will be possible.
...Synopsis & Discussion...
An upper low will move slowly from CA into NV on Thursday, with a
leading midlevel speed max forecast to move from UT northward across
ID, OR and WA. Cooling aloft will occur along with 40-50 kt 500 mb
winds enhancing deep-layer shear. A surface trough will also deepen
during the afternoon roughly from UT into eastern WA, with strong
heating and steepening lapse rates aiding destabilization.
Scattered storms are forecast to develop by early afternoon over
central OR, with additional activity extending northeastward across
northern ID, eastern WA and northwest MT. Though total CAPE values
are questionably high by some models, sufficient instability will
exist, along with favorable large-scale ascent and steep lapse
rates. This will favor northwestward-moving cells and perhaps a few
bows, with at least isolated severe gusts or marginal hail expected.
Elsewhere, scattered storms are likely during the afternoon and
evening from KS/OK into the Southeast. Winds aloft and shear will be
weak across this entire region, and severe storms are largely not
expected. Still, sporadic strong gusts cannot be ruled out.
..Jewell.. 05/27/2026
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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0214 AM CDT Wed May 27 2026
Valid 291200Z - 301200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM EASTERN NEW
MEXICO INTO WESTERN TEXAS...AND OVER WESTERN MONTANA...
...SUMMARY...
A few storms may produce large hail from eastern New Mexico into
western Texas on Friday. Strong storms may also occur across western
Montana with gusty winds and marginal hail.
...Southern High Plains...
Modest westerly flow aloft will spread across NM and into TX, with
cool midlevel temperatures resulting in steep lapse rates. A surface
trough will be situated over far eastern NM, and scattered storms
are likely to develop during the afternoon with 50s to near 60 F
dewpoints. Up to 30 kt deep-layer shear and ample
moisture/instability may support a few severe slow-moving cells
producing large hail. These storms will likely spread into the TX
Panhandle/South Plains during the evening, with localized wind
potential as well.
...Western MT...
An upper low/shortwave trough will move eastward across the Great
Basin on Friday, taking on a negative tilt. Extending north of this
low will be a belt of 30 kt southerly winds around 500 mb, with a
bit stronger speeds in the upper levels. A surface trough will
deepen over central MT, with a cold front pushing across western MT.
The cool temperatures aloft/steep lapse rate environment should
support at least marginal hail, while favorable afternoon timing
with boundary layer mixed layers will support strong downdrafts.
This should result in at least isolated strong to severe cells
moving northeastward across western MT during the afternoon.
..Jewell.. 05/27/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0246 AM CDT Wed May 27 2026
Valid 301200Z - 041200Z
...DISCUSSION...
On Saturday/D4, an upper low will weaken as it moves from UT into
WY, with midlevel wind speeds at or below 25 kt across the northern
Rockies/Plains. This feature will persist into Sunday/D5 and
Monday/D6 as it moves toward MT and eventually into Canada. Given
the weak winds aloft, severe potential should be relatively low, but
isolated strong storms may occur over parts of the northern Plains.
Farther south, stronger instability is forecast over the southern
and central Plains, where 60s to lower 70s F dewpoints will exist.
Although unstable, shear will be quite weak. Saturday/D4 may hold
slightly greater severe potential compared to other days, as the
southern lobe of the western trough lifts north out of the
southern/central Plains. However, shear will still be marginal, and
the likelihood antecedent precip/outflows lessens predictability in
the weak forcing pattern. The stronger instability air mass appear
most prominent through about Monday/D6. Thereafter, an upper trough
may amplify over the eastern CONUS, driving high pressure south
across the eastern CONUS/MS Valley.
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