WW 589 SEVERE TSTM IN 162050Z - 170100Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 589
NWS Storm Prediction Center Norman OK
450 PM EDT Sun Aug 16 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
South-central Indiana
* Effective this Sunday afternoon and evening from 450 PM until
900 PM EDT.
* Primary threats include...
Isolated damaging wind gusts to 70 mph possible
SUMMARY...A cluster of storms will likely continue to progress
east-southeastward across the region with damaging winds as the
primary hazard.
The severe thunderstorm watch area is approximately along and 30
statute miles north and south of a line from 10 miles northwest of
Terre Haute IN to 45 miles east southeast of Indianapolis IN. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU9).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 586...WW 587...WW 588...
AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few
cumulonimbi with maximum tops to 550. Mean storm motion vector
28030.
...Guyer
WW 588 SEVERE TSTM DC MD PA VA WV CW 162035Z - 170300Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 588
NWS Storm Prediction Center Norman OK
435 PM EDT Sun Aug 16 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
District Of Columbia
Maryland
Central Pennsylvania
Virginia
Eastern West Virginia
Coastal Waters
* Effective this Sunday afternoon and evening from 435 PM until
1100 PM EDT.
* Primary threats include...
Scattered damaging wind gusts to 65 mph likely
A tornado or two possible
SUMMARY...Multiple organized clusters of storms will likely cross
the mountains and generally persist east-southeastward into the
region, as the downstream air mass near/east of the mountains
destabilizes in the wake of early morning storms and cloud cover.
Damaging winds are the most common severe hazard expected, but some
tornado potential may exist as well, particularly near an effective
warm front.
The severe thunderstorm watch area is approximately along and 65
statute miles east and west of a line from 40 miles east northeast
of Altoona PA to 50 miles south southwest of Staunton VA. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU8).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 586...WW 587...
AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 55 knots. A few
cumulonimbi with maximum tops to 550. Mean storm motion vector
28030.
...Guyer
WW 587 SEVERE TSTM CO KS NE NM OK TX WY 162005Z - 170300Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 587
NWS Storm Prediction Center Norman OK
205 PM MDT Sun Aug 16 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Eastern Colorado
Far western Kansas
Western Nebraska
Northeast New Mexico
Oklahoma Panhandle
Texas Panhandle
Eastern Wyoming
* Effective this Sunday afternoon and evening from 205 PM until
900 PM MDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph possible
Scattered large hail events to 1.5 inches in diameter possible
SUMMARY...At least widely scattered severe thunderstorm development
is expected regionally this afternoon, with bouts of large hail and
locally damaging winds possible as storms drift east-southeastward.
The severe thunderstorm watch area is approximately along and 60
statute miles east and west of a line from 30 miles west northwest
of Chadron NE to 25 miles west southwest of Clayton NM. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU7).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 586...
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
28025.
...Guyer
WW 586 SEVERE TSTM OH PA WV 161705Z - 170000Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 586
NWS Storm Prediction Center Norman OK
105 PM EDT Sun Aug 16 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Eastern Ohio
Western Pennsylvania
West Virginia
* Effective this Sunday afternoon and evening from 105 PM until
800 PM EDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
A tornado or two possible
SUMMARY...Clusters of storms will continue to develop and intensify
across the region within a moist/unstable environment, with storm
organization influenced by an MCV-enhanced belt of flow aloft.
Damaging winds are the most common concern regionally, but a brief
tornado could occur.
The severe thunderstorm watch area is approximately along and 75
statute miles east and west of a line from 20 miles east northeast
of Youngstown OH to 15 miles south southeast of Charleston WV. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU6).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few
cumulonimbi with maximum tops to 550. Mean storm motion vector
29025.
...Guyer
WW 0589 Status Updates
STATUS FOR WATCH 0589 HAS NOT BEEN ISSUED YET
WW 0588 Status Updates
STATUS FOR WATCH 0588 HAS NOT BEEN ISSUED YET
WW 0587 Status Updates
STATUS REPORT ON WW 587
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..CHALMERS..08/16/26
ATTN...WFO...BOU...PUB...GLD...CYS...ABQ...AMA...
STATUS REPORT FOR WS 587
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
COC001-005-009-011-017-025-031-035-039-041-061-063-071-073-075-
087-089-095-099-101-115-119-121-123-125-162140-
CO
. COLORADO COUNTIES INCLUDED ARE
ADAMS ARAPAHOE BACA
BENT CHEYENNE CROWLEY
DENVER DOUGLAS ELBERT
EL PASO KIOWA KIT CARSON
LAS ANIMAS LINCOLN LOGAN
MORGAN OTERO PHILLIPS
PROWERS PUEBLO SEDGWICK
TELLER WASHINGTON WELD
YUMA
KSC071-199-162140-
KS
. KANSAS COUNTIES INCLUDED ARE
GREELEY WALLACE
NEC007-013-033-045-105-123-157-165-162140-
WW 0586 Status Updates
STATUS REPORT ON WW 586
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 NNW UNI
TO 30 W MGW TO 25 ESE YNG TO 15 W FKL.
..MEAD..08/16/26
ATTN...WFO...RLX...PBZ...CLE...
STATUS REPORT FOR WS 586
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
OHC009-053-079-087-105-115-163-167-162140-
OH
. OHIO COUNTIES INCLUDED ARE
ATHENS GALLIA JACKSON
LAWRENCE MEIGS MORGAN
VINTON WASHINGTON
PAC003-005-019-031-051-053-059-063-065-121-125-129-162140-
PA
. PENNSYLVANIA COUNTIES INCLUDED ARE
ALLEGHENY ARMSTRONG BUTLER
CLARION FAYETTE FOREST
GREENE INDIANA JEFFERSON
VENANGO WASHINGTON WESTMORELAND
WVC001-005-007-011-013-015-017-019-021-033-035-039-041-043-049-
053-061-067-073-075-077-079-081-083-085-087-091-093-095-097-101-
105-107-162140-
MD 2001 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR CENTRAL AND SOUTHERN MISSOURI INTO SOUTHWEST ILLINOIS
Mesoscale Discussion 2001
NWS Storm Prediction Center Norman OK
0311 PM CDT Sun Aug 16 2026
Areas affected...central and southern Missouri into southwest
Illinois
Concerning...Severe potential...Watch possible
Valid 162011Z - 162215Z
Probability of Watch Issuance...60 percent
SUMMARY...The threat for severe storms capable of mainly damaging
wind gusts is expected to increase across the area late this
afternoon into evening. A severe thunderstorm watch is possible.
DISCUSSION...Visible satellite and surface observations indicate a
couple of boundaries remnant from earlier storms located over the
region as of 20Z. Objective analysis shows, and visible satellite
confirms residual capping over northeast and east-central MO into
adjacent west-central and southwest IL. To the south of those areas
over central and southern MO, temperatures have warmed to around 100
F with considerably more boundary-layer-based cumulus development,
coincident with an uncapped environment with MLCAPE of 2000-3000
J/kg. That area resides to the south of the stronger forcing for
ascent and associated, stronger mid-level flow related to an MCV
moving along the IA-MO border.
Variability exists across the latest CAM guidance and time-lagged
ensembles in specific details regarding the preferred location(s)
for storm development later this afternoon. In general, there is a
signal for eventual upscale growth of initial more discrete storms
into an MCS, which tracks into southern IL this evening. Given the
presence of a hot, well-mixed boundary layer already in place across
central and southern MO, the setup appears favorable for at least
isolated damaging wind gusts with the most intense storms. A more
concentrated area of damaging wind potential may materialize this
evening should storms merge into an MCS along a coalescing cold
pool. Convective trends are being monitored for a possible watch
issuance.
..Mead/Guyer.. 08/16/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PAH...LSX...SGF...EAX...
LAT...LON 37769388 38189411 38729359 39219213 39219124 39339005
39088955 38198923 37698931 37078993 37019147 37179255
37429339 37769388
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MD 2000 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR SOUTH-CENTRAL PENNSYLVANIA...THE MARYLAND AND WEST VIRGINIA PANHANDLES...AND NORTHERN VIRGINIA
Mesoscale Discussion 2000
NWS Storm Prediction Center Norman OK
0228 PM CDT Sun Aug 16 2026
Areas affected...south-central Pennsylvania...the Maryland and West
Virginia Panhandles...and northern Virginia
Concerning...Severe potential...Watch likely
Valid 161928Z - 162130Z
Probability of Watch Issuance...80 percent
SUMMARY...The threat for severe storms capable of mainly damaging
wind gusts is expected to increase late this afternoon into evening.
A severe thunderstorm watch is likely.
DISCUSSION...In the wake of an MCV moving from south-central into
southeast PA, clouds are gradually clearing, allowing for increased
diabatic heating this afternoon. When coupled with a moist boundary
layer characterized by boundary-layer dewpoints in the upper 60s to
mid 70s F, latest objective analysis indicates MLCAPE of 1000-1500
J/kg with decreasing convective inhibition. Additional air mass
destabilization is expected through the remainder of the afternoon,
allowing ongoing QLCSs to spread east into the discussion area.
Damaging wind gusts will be the primary hazard with the most intense
storms, especially in the vicinity of any embedded bowing structures
that may persist. A brief tornado or two is possible in areas that
can maintain more of a southerly wind component, where low-level
shear is locally enhanced.
..Mead/Guyer.. 08/16/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...AKQ...CTP...LWX...RNK...PBZ...
LAT...LON 38357955 38947931 39407927 40267895 40477848 40397801
39307761 38237782 37877812 37537857 37497918 37897993
38357955
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1144 AM CDT Sun Aug 16 2026
Valid 161630Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FRONT
RANGE AND CENTRAL/NORTHERN HIGH PLAINS AND OHIO
VALLEY/MID-ATLANTIC...
...SUMMARY...
Thunderstorms with damaging wind gusts will be possible this
afternoon and early evening over parts of the Ohio Valley and
Mid-Atlantic. Large hail and isolated severe wind gusts will also be
possible across the Front Range and central/northern High Plains.
...Upper Ohio Valley to Appalachians and Mid-Atlantic/Carolinas...
An MCV persists at midday across far southeast Michigan and northern
Ohio, with some recent uptick in convection ahead of it across
northern Ohio. Reference Mesoscale Discussion 1195 for short-term
details regarding a further increase in severe potential through
early/mid-afternoon within this regional corridor.
While storms have weakened, showers/cloud cover remain prevalent
near/east of the Appalachians at midday across the Mid-Atlantic
region. This will tend to limit/delay destabilization in many areas
(especially with north-northeastward extent). That said, air mass
recovery/advection is expected from the west, with ample upstream
clearing per visible satellite imagery across the Cumberland Plateau
into parts of the Allegheny Plateau. Pending the timing/location of
destabilization, some terrain/lee trough-related development may
diurnally occur, although the most prevalent/more certain scenario
may be for potentially severe storms to spread into the region this
evening. Damaging winds will be the most common hazard regionally,
although a tornado could occur, attributable to MCV-enhanced flow
and/or with any storms interacting with the effective warm front
across the Mid-Atlantic region.
...Middle Mississippi Valley including Missouri/Illinois...
An MCV over the Nebraska/Kansas/Iowa/Missouri border vicinity late
this morning will likely continue generally eastward, while probably
largely maintaining its related belt of enhanced mid-level flow as
observed from regional WSR-88D VWP data. A key downstream
uncertainty is the midday persistence of weak convection across
eastern Missouri into west/southwest Illinois, and that mid-level
lapse rates are rather poor to its north aside from some lingering
cloud cover.
More certain/greater destabilization may occur to the west across
Missouri, with the southeastward-advancing front being a focus for
renewed thunderstorm development later this afternoon and evening
amidst moderate/locally strong buoyancy. Deep-layer shear will tend
to be limited to around 30 kt in most areas, although somewhat
stronger MCV-related winds aloft may support upwards of 35-40 kt
effective shear for any storms across northern Missouri into
west-central/southwest Illinois. Bouts of damaging winds are the
most likely hazard regionally.
...Front Range/Raton Mesa and northern/central High Plains...
A relatively similar pattern/scenario as prior few days will
continue regionally, except a somewhat more northward-extent of the
severe risk (such as Black Hills vicinity) and a trend toward a more
northerly component to the flow aloft across the north-central High
Plains. At least widely scattered thunderstorm development is
expected into mid/late afternoon spanning the Front Range/Raton Mesa
vicinity northward across eastern Wyoming/southeast Montana and the
Black Hills vicinity. In the presence of upwards of 1500-2000 J/kg
MLCAPE, moderate vertical shear (30-40 kt) could support a few
supercells capable of severe hail. Isolated damaging winds will be
possible. This includes the most probable zone for gradual
upscale-growing linear cluster(s) across the south-central High
Plains/Raton Mesa vicinity including southeast Colorado/northeast
New Mexico toward the Oklahoma/Texas Panhandles and far southwest
Kansas. A couple of southeastward-moving thunderstorm clusters
capable of wind/damage may also emerge this evening out of the Black
Hills vicinity/western Nebraska.
..Guyer/Chalmers.. 08/16/2026
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Sun Aug 16 2026
Valid 162000Z - 171200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITHIN THE FRONT
RANGE AND PARTS OF THE CENTRAL/NORTHERN HIGH PLAINS...AND PORTIONS
OF THE OHIO VALLEY INTO THE MID-ATLANTIC...
...SUMMARY...
Thunderstorms with damaging wind gusts will be possible this
afternoon and early evening over parts of the Ohio Valley and
Mid-Atlantic. Large hail and isolated severe wind gusts will also be
possible across the Front Range and central/northern High Plains.
...20Z Update...
Ongoing convection within the Upper Ohio Valley vicinity continues
eastward this afternoon. Behind this convection, buoyancy has been
reduced. Wind probabilities have also been reduced, though isolated
strong to marginally severe storms are possible where some airmass
recovery has occurred. Elsewhere, the forecast remains on track with
only minor changes to the general thunderstorm forecast.
..Wendt.. 08/16/2026
.PREV DISCUSSION... /ISSUED 1144 AM CDT Sun Aug 16 2026/
...Upper Ohio Valley to Appalachians and Mid-Atlantic/Carolinas...
An MCV persists at midday across far southeast Michigan and northern
Ohio, with some recent uptick in convection ahead of it across
northern Ohio. Reference Mesoscale Discussion 1195 for short-term
details regarding a further increase in severe potential through
early/mid-afternoon within this regional corridor.
While storms have weakened, showers/cloud cover remain prevalent
near/east of the Appalachians at midday across the Mid-Atlantic
region. This will tend to limit/delay destabilization in many areas
(especially with north-northeastward extent). That said, air mass
recovery/advection is expected from the west, with ample upstream
clearing per visible satellite imagery across the Cumberland Plateau
into parts of the Allegheny Plateau. Pending the timing/location of
destabilization, some terrain/lee trough-related development may
diurnally occur, although the most prevalent/more certain scenario
may be for potentially severe storms to spread into the region this
evening. Damaging winds will be the most common hazard regionally,
although a tornado could occur, attributable to MCV-enhanced flow
and/or with any storms interacting with the effective warm front
across the Mid-Atlantic region.
...Middle Mississippi Valley including Missouri/Illinois...
An MCV over the Nebraska/Kansas/Iowa/Missouri border vicinity late
this morning will likely continue generally eastward, while probably
largely maintaining its related belt of enhanced mid-level flow as
observed from regional WSR-88D VWP data. A key downstream
uncertainty is the midday persistence of weak convection across
eastern Missouri into west/southwest Illinois, and that mid-level
lapse rates are rather poor to its north aside from some lingering
cloud cover.
More certain/greater destabilization may occur to the west across
Missouri, with the southeastward-advancing front being a focus for
renewed thunderstorm development later this afternoon and evening
amidst moderate/locally strong buoyancy. Deep-layer shear will tend
to be limited to around 30 kt in most areas, although somewhat
stronger MCV-related winds aloft may support upwards of 35-40 kt
effective shear for any storms across northern Missouri into
west-central/southwest Illinois. Bouts of damaging winds are the
most likely hazard regionally.
...Front Range/Raton Mesa and northern/central High Plains...
A relatively similar pattern/scenario as prior few days will
continue regionally, except a somewhat more northward-extent of the
severe risk (such as Black Hills vicinity) and a trend toward a more
northerly component to the flow aloft across the north-central High
Plains. At least widely scattered thunderstorm development is
expected into mid/late afternoon spanning the Front Range/Raton Mesa
vicinity northward across eastern Wyoming/southeast Montana and the
Black Hills vicinity. In the presence of upwards of 1500-2000 J/kg
MLCAPE, moderate vertical shear (30-40 kt) could support a few
supercells capable of severe hail. Isolated damaging winds will be
possible. This includes the most probable zone for gradual
upscale-growing linear cluster(s) across the south-central High
Plains/Raton Mesa vicinity including southeast Colorado/northeast
New Mexico toward the Oklahoma/Texas Panhandles and far southwest
Kansas. A couple of southeastward-moving thunderstorm clusters
capable of wind/damage may also emerge this evening out of the Black
Hills vicinity/western Nebraska.
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1232 PM CDT Sun Aug 16 2026
Valid 171200Z - 181200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
NORTHERN PLAINS...AND FROM THE SOUTHERN APPALACHIANS INTO THE
CAROLINAS...
...SUMMARY...
Strong to severe thunderstorms are possible Monday afternoon and
evening across portions of the northern and central Plains, and
parts of the southern Appalachians/Carolinas. Isolated severe gusts
may occur over Oklahoma.
...Northern Plains...
Stronger winds aloft will overspread the area on Monday with a front
pushing across the region. While temperatures aloft will be cool,
low-level moisture will not be excessive.
Storms are expected to form by 20Z over eastern ND and west-central
MN, and over the Black Hills. The steep lapse rate environment, with
modest MUCAPE values of 1000-1500 J/kg along with elongated mid to
upper level hodographs will favor cells producing hail over 1.00". A
greater/more concentrated severe risk is expected near and after
00Z, as activity matures as it moves southeastward into stronger
instability from NE into southeast SD. Additional cells are also
anticipated over central NE. Large hail is probable with all this
activity, with scattered severe gusts as storms merge/cluster during
the evening. A brief tornado cannot be ruled out late day/early
evening as low-level shear increases with a southwesterly low-level
jet.
...Southern Appalachians/Carolinas Vicinity...
The ridge over the Southeast will weaken a bit as a midlevel waves
moves through during the day. Speed at 500 mb will average near 30
kt, with 15-20 kt at 850 mb. This will aid southeastward storm
motions as development occurs within the surface trough/wind shift
from NC and southern VA into TN. Precipitable water near 2.00"
combined with the afternoon well-mixed boundary layer should support
gusty outflow winds, with a few severe gusts over 50 kt possible.
Activity should wane after about 03Z.
...Parts of OK into AR...
Dewpoints are forecast to be relatively high near a weakening
boundary/wind shift that will extend roughly from the TX Panhandle
across central/southern OK and into central AR. Daytime heating will
then lead to a narrow east-west oriented corridor of steep boundary
layer lapse rates, and strong instability. Shear will be weak, and
so will forcing for ascent. However, several CAMs indicate at least
isolated cells developing during the late afternoon, and locally
severe downbursts may occur.
..Jewell.. 08/16/2026
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0236 PM CDT Sun Aug 16 2026
Valid 181200Z - 191200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
CENTRAL PLAINS TO LOWER MISSOURI/MID MISSISSIPPI VALLEY...
...SUMMARY...
Severe thunderstorms capable of large hail and damaging wind gusts
are expected Tuesday afternoon/evening across parts of the central
Plains and toward the Lower Missouri/Mid-Mississippi Valley.
...NE/IA/KS/MO...
Moderate northwest flow aloft will exist across the region, with
some cooling aloft late in the day. Low pressure will develop over
western KS into southwest NE ahead of a convectively enhanced front
which will drop south across I-80 in NE/IA. The presence of morning
thunderstorms may further augment the boundary, and lends
uncertainty to positioning. However, a plume of strong heating will
exist as southwest low-level winds develop during the day near an
east of the surface low, and strong instability may develop across
the warm sector.
The area over NE appears quite favorable for supercells given some
model progs, with deep-layer shear to 50 kt, and increased SRH near
the boundary. Given the expected southeastward storm motions,
supercells could remain on any such boundary, with isolated tornado
potential. Very large hail may also occur with the late
afternoon/early evening cells before likely mergers into an MCS,
which may produce damaging winds as far south as northeast KS and
northern MO.
Given uncertainties, will maintain 15% coverage, but with
conditional CIG1 area.
..Jewell.. 08/16/2026
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1136 AM CDT Sun Aug 16 2026
Valid 161700Z - 171200Z
...NO CRITICAL AREAS...
Good overnight humidity recoveries occurred where dry fuels remain
in the Northwest and portions of the southern Plains. A cold front
has stalled across northern Oklahoma, and will slowly push southward
this evening/overnight. The 12z sounding from OUN sampled a 1.74"
PWAT, nearing the 90th percentile climatology, alongside 1000+ J/kg
of MUCAPE. Forecast soundings depict shallow inverted-V profiles
with gradual moistening of the mid-levels through the afternoon amid
weak flow, suggesting greater precipitation efficiency is likely
with any afternoon thunderstorm near/north of the front; thus,
precludes an isolated dry thunderstorm risk. Despite many
consecutive days of hot, dry, and windy conditions, modest RH values
of 20% or greater are expected. However, ERCs will remain at the
95-98th percentiles, allowing a threat for lightning ignitions to
emerge on the periphery of accumulating rainfall. The rest of the
forecast remains on track, please see the previous discussion for
more information.
..Elizalde-Garcia.. 08/16/2026
.PREV DISCUSSION... /ISSUED 0151 AM CDT Sun Aug 16 2026/
...Synopsis...
The prominent mid-level ridge over the central and western US will
begin to weaken under the influence of multiple upper-level troughs
today and tonight. The primary upper trough will move eastward
across the northern portions of the ridge near the Canadian border.
This will force a stalled front over the Plains southward while
monsoon moisture is shunted eastward with a second weaker trough
approaching the West Coast. While overall fire-weather concerns are
low, some lightning and dry/breezy conditions are possible over
parts of the southern Plains and Great Basin/Northern Rockies.
...Southern Plains...
The cold front is forecast to move south across parts of the TX
Panhandle and OK today supporting scattered showers and
thunderstorms. Likely higher-based owing to very warm surface
temperatures south of the front, these storms may develop over ares
of very dry fuels. However, slow storm speeds and increasing
moisture along the front suggest limited potential for dry storms.
Gusty and erratic winds may accompany storm outflow.
...Northern Great Basin and Northern Rockies...
The primary plume of monsoon moisture is forecast to shift eastward
as the ridge begins to flatten somewhat over the northern Rockies in
response to the troughing over the northern US. This will shift the
primary axis of diurnal thunderstorm activity farther east into ID,
MT and WY where recent wetting rainfall has occurred. While
thunderstorms again appear likely, much of this activity should be
fairly favorable for wetting rainfall, and occurring where fuels are
much less receptive to lightning than the previous days.
Farther south into parts of southern OR, northern NV and northeast
CA, weak troughing impinging on the western fringes of the upper
ridge may locally bolster westerly surface winds this afternoon.
Warm and dry conditions, along with wind gusts of 10-15 mph could
support a few hours of dry/breezy conditions where fuels are
relatively drier. Locally elevated conditions are possible, but
broader fire-weather concerns are unlikely due to the modest winds.
...Please see www.spc.noaa.gov/fire for graphic product...
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0238 PM CDT Sun Aug 16 2026
Valid 171200Z - 181200Z
On Day 2/Monday, forecast 80-90th percentile ERCs will expand across
northern California, the Pacific Northwest, portions of Idaho into
far northwestern Montana. On a broader scale, 72-hr cumulative
observed rainfall has been minimal (up to 0.2") in southern Idaho
and the Panhandle, with only the central Idaho higher-terrain
receiving 0.5-0.9". A receptive fuelscape remains, proven by several
new starts across southwestern ID and eastern OR. Depending on the
timing and location of the approaching shortwave trough, an isolated
thunderstorm over dry fuels is possible, albeit low (5-10% chance).
Dry thunderstorm highlights were not introduced in this update,
though may be needed in the next outlook cycle if high resolution
guidance indicates increased probabilities of isolated dry
thunderstorms over dry fuels. The rest of the forecast remains on
track; please see the previous discussion for more information.
..Elizalde-Garcia.. 08/16/2026
.PREV DISCUSSION... /ISSUED 0152 AM CDT Sun Aug 16 2026/
...Synopsis...
The upper ridge over the central and western US is forecast to
continue weakening as the upper trough deepens over the northern US
and another moves onshore over the West Coast. The increase in
westerly flow aloft will bolster surface winds over parts of
northern CA and the Great Basin with dry and breezy conditions
possible. Additionally, scattered thunderstorms are expected over
much of the Rockies, though likely with wetting rainfall.
...Northern Great Basin and northeast CA...
As the shortwave moves onshore over the West, dry and breezy
conditions are expected over parts of the northern Great Basin into
northeastern CA on Day 2/Monday. Largely devoid of recent rainfall
over the last several days, fuels remain quite dry. Warm afternoon
temperatures and dry westerly flow of 15-20 mph are expected ahead
of the upper trough. Afternoon RH minimums of 12-20% are also
likely. This will support several hours of elevated fire-weather
conditions from northeastern CA into parts of NV and southern OR.
...Northern Rockies...
Ascent from the approaching upper trough will support another round
of showers and thunderstorms over parts of ID, MT and northern WY.
Despite more limited monsoon moisture (PWATS 0.6-0.9 inches) several
days of wetting rainfall have tempered fuels such that dry storms
and lightning ignitions are expected to be sporadic.
...Please see www.spc.noaa.gov/fire for graphic product...
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