RSS Mesoscale Discussions from Storm Prediction Center
No watches are valid as of Mon Apr 20 10:50:02 UTC 2026.
No Mesoscale Discussions are in effect as of Mon Apr 20 10:50:02 UTC 2026.
SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0227 AM CDT Mon Apr 20 2026
Valid 221200Z - 231200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF THE HIGH PLAINS OF NEBRASKA SOUTH INTO THE TEXAS PANHANDLE...
...SUMMARY...
Severe thunderstorms capable of hail and gusty winds may develop
during the late afternoon and evening across portions of the High
Plains. Elsewhere, thunderstorms will be possible across the
northern Gulf Coast and portions of the Ohio Valley.
... Synopsis ...
A shortwave trough will eject northeast out of the basal region of
the western CONUS trough and into the northern Plains on Wednesday.
As this happens, strengthening southerly/southwesterly midlevel flow
will overspread much of the High Plains. A surface cyclone over
eastern Montana will gradually deepen as it slowly moves east.
... Central High Plains south into the southern High Plains ...
As the Montana surface cyclone gradually deepens on Wednesday, Gulf
moisture will be drawn northward into the central and northern
Plains. As the upper trough approaches the region during the late
afternoon/evening, modest height falls are expected to overspread a
sharpening dryline across far eastern Colorado or western Nebraska
south into the Texas Panhandle. Kinematic profiles up and down the
dryline show ample vertical shear for supercells capable of
producing hail and gusty winds. However, considerable uncertainty
remains regarding thunderstorm coverage owing to the significant
differences in the depth and quality of the boundary layer moisture
return noted in the 20260420/00Z guidance suite. For example, the
NAM is nearly 5F more moist along the dryline across portions of
Nebraska than global models.
That said, pattern recognition and 00Z RRFS suggest that at least a
couple of storms should develop along the dryline from Nebraska
south into the eastern Texas Panhandle. Deep-layer flow will largely
parallel the dryline during the afternoon which should preclude much
eastward advancement. A 5% unconditional risk area has been added to
account for this potential.
... Elsewhere Across the CONUS ...
Thunderstorms may be ongoing at the start of the forecast period and
persist into the early afternoon across portions of the northern
Gulf Coast. The thunderstorm potential should wane with time as
increasing midlevel heights suppress large-scale ascent.
Additionally, modest low-level moisture and weak instability may
support a few lightning strikes within a weak surface boundary
across the Ohio Valley.
..Marsh.. 04/20/2026
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Day 4-8 Outlook
Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0358 AM CDT Mon Apr 20 2026
Valid 231200Z - 281200Z
...DISCUSSION...
In the days preceding this forecast period, a long-wave trough will
develop across the western US. This feature will persist across the
western and central US through the forecast period supporting a
multi-day severe weather threat across portions of the central US.
On Thursday/Day-4, a lobe of vorticity will rotate around the closed
midlevel low across the northern Rockies. This will reinforce a
surface cyclone as it moves north into Canada. As this low moves
north, a combined dryline/cold front will move east into an
increasingly moist environment across the central Plains. The
airmass ahead of the front should destabilize during the day
Thursday, with MUCAPE values over 1000 J/kg possible into portions
of Minnesota.
Thunderstorms should develop across portions of northeast Kansas
into Iowa during the late afternoon as height falls overspread the
surface front. These storms should quickly build southward along the
front into portions of Oklahoma and southern Kansas. Kinematic
fields initially should support supercells, but midlevel flow will
increasingly become parallel to the front suggesting that storms
will grow upscale into one or more linear segments.
The surface front, augmented by convective outflows, will continue
to push south and east into the Southern Plains and the greater
ArkLaTex region overnight Thursday into Friday/Day-5 before stalling
out. Forecast soundings along and ahead of the frontal boundary
indicate an unstable, uncapped environment with vertical shear
between 30-40 knots should support additional severe thunderstorms
Friday afternoon into the evening/overnight across portions of
eastern Oklahoma and Arkansas.
By Saturday/Day-6, the larger-scale flow across the southern Plains
will begin to respond to a low-latitude trough moving into southern
California by once again becoming increasingly southwesterly.
Embedded perturbations within this southwest flow ahead of the main
trough will support an ongoing severe threat across the southern
Plains. However, the location of various surface boundaries
(dryline, outflow, frontal) will be predicated on the evolution of
prior days of convection and the timing of the aforementioned
perturbations in the midlevel flow. Thus, while pattern recognition
suggests severe weather will be possible on Days 6,7, and 8,
certainty as to the location of greatest severe potential on any
given day remains too low to highlight with unconditional
probabilities at this time.
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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0128 AM CDT Mon Apr 20 2026
Valid 201200Z - 211200Z
...Synopsis...
Upper-level ridging will gradually shift eastward from the Rockies
into the Plains through today as an upper-level trough departs the
East Coast and a second, closed upper trough approaches the West
Coast. Surface high pressure will shift east over the
Southeast/Mid-Atlantic while a lee trough deepens along the
central/northern High Plains.
...Portions of the central High Plains...
A deepening lee trough along the central High Plains will support
strengthening westerly downslope winds to the west of the trough
axis across portions of southeastern Wyoming into southwest South
Dakota and much of western/central Nebraska. Farther south/east,
high pressure over the Lower Mississippi Valley in conjunction with
the lee trough will yield a tightened surface pressure gradient and
strengthening southerly winds from the TX/OK Panhandle vicinity
northeastward into central Kansas and south-central Nebraska.
Sustained winds of 15-20 mph are expected within both of these
regimes. RH minimums of 10-15% (locally lower) are expected across
southeast Wyoming, southwest South Dakota, and western Nebraska
where downslope wind will depress moisture content within an
antecedent dry air mass. Farther south/east, the northern fringe of
returning moisture may limit RH reductions to some degree, but RH
minimums are still forecast to fall to 15-25% southeastern Colorado
northeastward into south-central Nebraska. With dry, receptive fuels
across much of the region, this will support widespread elevated
fire weather conditions for a few hours this afternoon. Locally
critical conditions will also be possible in the lee of the Laramie
Mountains in southeastern Wyoming where winds may occasionally gust
to 30-35 mph.
...Portions of the Southeast...
A dry air mass will continue to reside across much of the Southeast
where fuels remain exceptionally dry (ERCs above the 95th
percentile) amid continuing drought. Sustained northeasterly winds
of 10-15 mph along the southern periphery of surface high pressure
are forecast to overlap minimum RH values of 15-25% across much of
the Florida Panhandle and adjacent areas of southern
Alabama/Georgia. Farther north, modest westerly/northwesterly
downslope winds of 10-15 mph are forecast behind a dry, secondary
cold frontal passage, with minimum RH of 20-30% (locally lower)
expected. This combination of winds/RH is expected to support
elevated fire weather concerns across much of the Southeast this
afternoon.
...Portions of New Mexico into eastern Arizona...
Low to mid-level moisture return is forecast across southern Texas
into portions of the Southwest through this afternoon. Although
forcing for ascent will remain modest under an upper-level ridge, a
combination of localized orographic ascent, deeply mixed boundary
layers with minimal inhibition, and a weak, subtle mid-level
shortwave trough will support isolated thunderstorm development this
afternoon. Slow storm motions (around 10 kts) will likely support
pockets of wetting precipitation, but PWAT values of 0.4-0.7" atop a
dry sub-cloud layer will likely support dry lightning strikes while
largely limiting precipitation. With regional ERCs near the 75th to
80th percentile, lightning ignitions appear possible. While
prevailing flow is forecast to remain weak, gusty outflow winds may
create erratic fire behavior with any new ignitions.
...Portions of the Upper Midwest...
A tightened surface pressure gradient will promote sustained
southwesterly winds of 20-25 mph, with the potential for gusts to
30-35 mph, across portions of the Upper Midwest, especially across
the eastern Dakotas and much of Minnesota. RH values are forecast to
fall to 25-30% this afternoon, with lower values possible should
forecast cloud cover clear more quickly this morning/afternoon. This
combination of wind/RH may promote locally elevated fire weather
concerns this afternoon, especially in pockets of drier fine fuels.
Recent precipitation across portions of this area along with
marginal fuel receptiveness and uncertainty regarding cloud cover
preclude the addition of Elevated highlights at this time.
..Chalmers.. 04/20/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0129 AM CDT Mon Apr 20 2026
Valid 211200Z - 221200Z
...Synopsis...
Upper-level ridging will gradually slide east over the Great Plains
on D2/Tuesday as a closed upper-level low moves onshore across the
West Coast. At the surface, high pressure will build into the
Southeast while a frontal system advances across the northern Great
Plains and Upper Midwest.
...Portions of Florida into southern Georgia...
Sustained easterly winds of 10-15 mph along the southeastern
periphery of high pressure building into the Southeast will overlap
reduced RH of 20-30% across much of the Florida Peninsula and into
southern Georgia Tuesday afternoon. Continued dry conditions amid
extreme to exceptional drought continues to promote receptive fuels
across this region, with ERCs currently at or above the 95th
percentile. This combination is expected to support elevated fire
weather concerns for at least a few hours. While winds are currently
forecast to remain below critical criteria, locally critical
conditions may be possible given the dryness/receptiveness of fuels
and potential for occasional wind gusts to 20 mph.
..Chalmers.. 04/20/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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