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

No watches are valid as of Mon Apr 20 07:29:02 UTC 2026.

No Mesoscale Discussions are in effect as of Mon Apr 20 07:29:02 UTC 2026.

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...

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...

SPC 0600Z Day 2 Outlook

Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1247 AM CDT Mon Apr 20 2026

Valid 211200Z - 221200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Thunderstorms will be possible across the western CONUS, the
south-central CONUS, and the southern Great Lakes on Tuesday.
Potential for severe weather appears low.

... Synopsis ...

Midlevel ridging will be in place from the eastern Great Basin into
the Plains at the start of the forecast period, while persistent
northwesterly flow aloft continues across the Upper Midwest and Ohio
Valley. Farther west, an upper trough will gradually advanced inland
across California into the Great Basin by the end of the period. 

At the surface, a broad area of high pressure centered over the
Southeast and adjacent Atlantic will maintain southerly flow across
the central US. This will promote a gradual moisture recovery across
the central Plains into the southern Great Lakes. A weak frontal
boundary pushing south through portions of the central Plains and
Great Lakes will denote the northern edge of the moisture return.

... Lower Great Lakes ...

Thunderstorm development along the frontal zone may be delayed until
later in the day or evening as moisture slowly returns northward.
While relatively cold temperatures aloft should support steep lapse
rates, the quality and depth of the boundary-layer moisture is
expected to be the biggest unknown. The NAM is the most aggressive
with the depth and quality of the moisture return, and if moisture
quality is close to what is shown in the NAM, enough instability
should materialize to take advantage of the stronger vertical shear
to support a few organized cells capable of gusty winds or small
hail. However, most model guidance is less aggressive with the
quality of the moisture return so no probabilities have been added
at this time. 

... South-central US ...

Convection will likely be ongoing at the start of the forecast
period. Modest vertical shear and elevated instability may support a
couple strong thunderstorms capable of hail and gusty winds.
However, overall thunderstorm intensity should wane through much of
the period as upper ridging overspreads the region.

... Western US ...

As the upper trough moves inland, ascent will increase across the
Pacific Northwest, northern California, and portions of the Great
Basin. Within the Central Valley and nearby terrain, pockets of
diurnal heating, combined with cool midlevel temperatures may
support isolated thunderstorm development during the afternoon.
Despite this modest instability, weak vertical shear should limit
any organized severe potential.

..Marsh.. 04/20/2026

SPC 1200Z Day 1 Outlook

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1118 PM CDT Sun Apr 19 2026

Valid 201200Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Severe storms are not expected today.

...Synopsis...
An upper trough will exit the northeastern states today, with
northwest flow aloft extending from the northern Plains to the East
Coast. Upper ridging will occur over the Rockies, while a large
upper trough slowly approaches the West Coast.

At the surface, high pressure will result in relatively stable
conditions for much of the central and eastern CONUS, with centers
over the Mid Atlantic and near the northern Gulf Coast.

In the wake of the eastern trough, winds just off the surface will
maintain a zone of elevated moisture and instability over much of
TX, where scattered showers and storms will be most likely. Weak
instability will preclude any severe storm chances there.

To the west, cooling aloft with the approaching upper trough will
support weak instability into parts of OR and WA, with isolated late
day thunderstorms possible over portions of the Cascades.
Small/non-severe hail cannot be ruled out, along with locally gusty
winds mainly in the 00-03Z time frame.

..Jewell/Chalmers.. 04/20/2026