WW 346 TORNADO WI 172235Z - 180200Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 346
NWS Storm Prediction Center Norman OK
535 PM CDT Wed Jun 17 2026
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Southwest into Southern Wisconsin
* Effective this Wednesday afternoon and evening from 535 PM
until 900 PM CDT.
* Primary threats include...
A couple tornadoes possible
Scattered damaging wind gusts to 65 mph possible
Scattered large hail events to 1.5 inches in diameter possible
SUMMARY...A couple of severe thunderstorms will likely persist into
the evening across the Watch area immediately east of a surface low.
A couple of supercell tornadoes are possible in addition to a risk
for severe gusts and large hail.
The tornado watch area is approximately along and 35 statute miles
north and south of a line from 35 miles west of Lonerock WI to 20
miles south of Madison WI. For a complete depiction of the watch see
the associated watch outline update (WOUS64 KWNS WOU6).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and 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.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 341...WW 342...WW
343...WW 344...WW 345...
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1.5 inches. Extreme turbulence and surface wind
gusts to 55 knots. A few cumulonimbi with maximum tops to 300. Mean
storm motion vector 30035.
...Smith
WW 345 TORNADO MO 172220Z - 180300Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 345
NWS Storm Prediction Center Norman OK
520 PM CDT Wed Jun 17 2026
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
West-Central into Central Missouri
* Effective this Wednesday afternoon and evening from 520 PM
until 1000 PM CDT.
* Primary threats include...
A couple tornadoes possible
Widespread damaging winds and isolated significant gusts to 75
mph likely
Scattered large hail and isolated very large hail events to 3
inches in diameter likely
SUMMARY...Several supercells will continue to intensify through the
late afternoon and persist into the evening across the Watch area.
A moist and unstable airmass with environmental wind shear favorable
for supercells is present over the area. The threat for a couple of
tornadoes, large to very large hail, and severe gusts is forecast.
The tornado watch area is approximately along and 50 statute miles
north and south of a line from 45 miles southwest of Knob Noster MO
to 75 miles east southeast of Knob Noster MO. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU5).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and 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.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 341...WW 342...WW
343...WW 344...
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 3 inches. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 550. Mean
storm motion vector 28035.
...Smith
WW 344 TORNADO IN 172135Z - 180500Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 344
NWS Storm Prediction Center Norman OK
535 PM EDT Wed Jun 17 2026
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Southern into Central and North-Central Indiana
* Effective this Wednesday afternoon and Thursday morning from
535 PM until 100 AM EDT.
* Primary threats include...
A few tornadoes and a couple intense tornadoes likely
Widespread damaging winds and isolated significant gusts to 80
mph likely
Scattered large hail and isolated very large hail events to 2.5
inches in diameter likely
SUMMARY...Severe thunderstorms are forecast to move east into the
Watch this evening and continue into the early overnight.
Supercells capable of tornadoes, some of which will probably be
strong, large to very large hail, and severe gusts are expected with
this activity.
The tornado watch area is approximately along and 70 statute miles
north and south of a line from 25 miles northwest of Terre Haute IN
to 30 miles south southeast of Muncie IN. For a complete depiction
of the watch see the associated watch outline update (WOUS64 KWNS
WOU4).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and 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.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 341...WW 342...WW 343...
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2.5 inches. Extreme turbulence and surface wind
gusts to 70 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 27040.
...Smith
WW 343 SEVERE TSTM KS MO 171935Z - 180300Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 343
NWS Storm Prediction Center Norman OK
235 PM CDT Wed Jun 17 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Eastern Kansas
Western and Central Missouri
* Effective this Wednesday afternoon and evening from 235 PM
until 1000 PM CDT.
* Primary threats include...
Scattered damaging winds and isolated significant gusts to 75
mph likely
Scattered large hail and isolated very large hail events to 3
inches in diameter likely
A tornado or two possible
SUMMARY...Thunderstorms will rapidly develop this afternoon along a
cold front and sag southeastward across the watch area through the
evening. Severe/supercell storms capable of very large hail and
damaging winds are possible. A tornado or two may also occur.
The severe thunderstorm watch area is approximately along and 70
statute miles north and south of a line from 35 miles west northwest
of Chanute KS to 70 miles east northeast of Knob Noster MO. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU3).
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 341...WW 342...
AVIATION...A few severe thunderstorms with hail surface and aloft to
3 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
28035.
...Hart
WW 342 TORNADO IL MO 171915Z - 180300Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 342
NWS Storm Prediction Center Norman OK
215 PM CDT Wed Jun 17 2026
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Central Illinois
Eastern Missouri
* Effective this Wednesday afternoon and evening from 215 PM
until 1000 PM CDT.
* Primary threats include...
Several tornadoes and a couple intense tornadoes likely
Scattered damaging winds and isolated significant gusts to 75
mph likely
Scattered large hail and isolated very large hail events to 3
inches in diameter likely
SUMMARY...Intense thunderstorms are expected to develop this
afternoon over eastern Missouri and western Illinois, tracking
across the watch through the evening. Supercells capable of
tornadoes, large hail, and damaging winds are all possible with
these storms.
The tornado watch area is approximately along and 75 statute miles
north and south of a line from 30 miles north northwest of Columbia
MO to 35 miles east northeast of Mattoon IL. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU2).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and 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.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 340...WW 341...
AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 3 inches. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 28035.
...Hart
WW 0346 Status Updates
STATUS REPORT ON WW 346
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 NW DBQ TO
30 NE LNR.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1170
..DEAN..06/17/26
ATTN...WFO...ARX...MKX...
STATUS REPORT FOR WT 346
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
WIC025-043-045-049-065-180040-
WI
. WISCONSIN COUNTIES INCLUDED ARE
DANE GRANT GREEN
IOWA LAFAYETTE
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
WW 0345 Status Updates
STATUS REPORT ON WW 345
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1169
..DEAN..06/17/26
ATTN...WFO...EAX...SGF...
STATUS REPORT FOR WT 345
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
MOC013-015-029-039-053-059-083-085-089-105-125-131-141-159-161-
167-169-185-180040-
MO
. MISSOURI COUNTIES INCLUDED ARE
BATES BENTON CAMDEN
CEDAR COOPER DALLAS
HENRY HICKORY HOWARD
LACLEDE MARIES MILLER
MORGAN PETTIS PHELPS
POLK PULASKI ST. CLAIR
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
WW 0344 Status Updates
STATUS REPORT ON WW 344
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 WNW DNV
TO 20 SSE FWA.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1171
..WEINMAN..06/17/26
ATTN...WFO...IND...IWX...
STATUS REPORT FOR WT 344
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
INC005-009-011-013-021-023-027-031-035-045-053-055-057-059-063-
065-067-071-075-079-081-083-093-095-097-101-105-107-109-119-121-
133-135-139-145-153-157-159-165-167-171-180140-
IN
. INDIANA COUNTIES INCLUDED ARE
BARTHOLOMEW BLACKFORD BOONE
BROWN CLAY CLINTON
DAVIESS DECATUR DELAWARE
FOUNTAIN GRANT GREENE
HAMILTON HANCOCK HENDRICKS
HENRY HOWARD JACKSON
JAY JENNINGS JOHNSON
KNOX LAWRENCE MADISON
MARION MARTIN MONROE
MONTGOMERY MORGAN OWEN
PARKE PUTNAM RANDOLPH
RUSH SHELBY SULLIVAN
TIPPECANOE TIPTON VERMILLION
VIGO WARREN
WW 0343 Status Updates
STATUS REPORT ON WW 343
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 SW EMP TO
20 ESE MKC TO 30 SE IRK.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1169
..DEAN..06/17/26
ATTN...WFO...ICT...TOP...SGF...EAX...
STATUS REPORT FOR WS 343
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
KSC001-003-011-019-021-031-037-049-059-073-099-107-121-125-133-
205-207-180040-
KS
. KANSAS COUNTIES INCLUDED ARE
ALLEN ANDERSON BOURBON
CHAUTAUQUA CHEROKEE COFFEY
CRAWFORD ELK FRANKLIN
GREENWOOD LABETTE LINN
MIAMI MONTGOMERY NEOSHO
WILSON WOODSON
MOC011-037-057-097-101-107-195-217-180040-
MO
. MISSOURI COUNTIES INCLUDED ARE
BARTON CASS DADE
JASPER JOHNSON LAFAYETTE
SALINE VERNON
WW 0342 Status Updates
STATUS REPORT ON WW 342
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 S IRK TO
15 E DNV.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1171
..WEINMAN..06/17/26
ATTN...WFO...LSX...ILX...LOT...DVN...
STATUS REPORT FOR WT 342
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
ILC001-005-009-013-017-019-021-023-025-027-029-033-035-039-041-
045-049-051-061-079-083-101-107-115-117-119-121-129-133-135-137-
139-147-149-159-163-167-171-173-183-189-180140-
IL
. ILLINOIS COUNTIES INCLUDED ARE
ADAMS BOND BROWN
CALHOUN CASS CHAMPAIGN
CHRISTIAN CLARK CLAY
CLINTON COLES CRAWFORD
CUMBERLAND DE WITT DOUGLAS
EDGAR EFFINGHAM FAYETTE
GREENE JASPER JERSEY
LAWRENCE LOGAN MACON
MACOUPIN MADISON MARION
MENARD MONROE MONTGOMERY
MORGAN MOULTRIE PIATT
PIKE RICHLAND ST. CLAIR
SANGAMON SCOTT SHELBY
VERMILION WASHINGTON
WW 0341 Status Updates
STATUS REPORT ON WW 341
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 NNE ALO
TO 15 W LSE TO 30 ESE EAU.
..LYONS..06/17/26
ATTN...WFO...ARX...MPX...
STATUS REPORT FOR WS 341
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
IAC005-191-172240-
IA
. IOWA COUNTIES INCLUDED ARE
ALLAMAKEE WINNESHIEK
MNC055-172240-
MN
. MINNESOTA COUNTIES INCLUDED ARE
HOUSTON
WIC023-063-123-172240-
WI
. WISCONSIN COUNTIES INCLUDED ARE
CRAWFORD LA CROSSE VERNON
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
MD 1171 CONCERNING TORNADO WATCH 342...344... FOR PARTS OF SOUTH-CENTRAL ILLINOIS INTO SOUTHWEST INDIANA
Mesoscale Discussion 1171
NWS Storm Prediction Center Norman OK
0650 PM CDT Wed Jun 17 2026
Areas affected...Parts of south-central Illinois into southwest
Indiana
Concerning...Tornado Watch 342...344...
Valid 172350Z - 180145Z
The severe weather threat for Tornado Watch 342, 344 continues.
SUMMARY...Large hail, damaging winds, and the potential for a few
tornadoes will continue spreading east-southeastward this evening --
within Tornado Watches 342/344.
DISCUSSION...A couple supercells are tracking east-southeastward
along the southern flank of a larger convective cluster in
east-central/southeast IL -- with additional
development/intensification farther west in south-central IL.
Despite the presence of very strong low/deep-layer flow/shear
sampled by the IND VWP (60 kt low-level jet and 650-700 m2/s2 0-1 km
SRH), these storms are tracking through a corridor of convectively
processed air from earlier storms. However, the strong low-level
mass response accompanying an approaching midlevel wave may support
additional boundary-layer recovery toward the inflow of these storms
during the next few hours. If this can occur, the robust low-level
shear/streamwise vorticity will support a few tornadoes (some of
which could be strong-intense) with any longer-lived supercells.
Very large hail and severe wind gusts (75+ mph) will also be
possible with these storms as they continue east-southeastward.
..Weinman.. 06/17/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IND...ILX...LSX...
LAT...LON 39128678 38888686 38788721 38928769 39158879 39188973
39368996 39648986 39718954 39718833 39598770 39458719
39338688 39128678
MOST PROBABLE PEAK TORNADO INTENSITY...120-145 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN
MD 1170 CONCERNING TORNADO WATCH 346... FOR PARTS OF SOUTHWEST WI AND VICINITY
Mesoscale Discussion 1170
NWS Storm Prediction Center Norman OK
0555 PM CDT Wed Jun 17 2026
Areas affected...Parts of southwest WI and vicinity
Concerning...Tornado Watch 346...
Valid 172255Z - 180030Z
The severe weather threat for Tornado Watch 346 continues.
SUMMARY...Ongoing tornado potential may continue through early
evening. Isolated hail and damaging wind are also possible.
DISCUSSION...A noticeable uptick in storm organization has recently
occurred across extreme northeast IA, with supercell evolution and
development of a relatively long-lived tornado. The embedded
supercell is now moving into southwest WI. While instability remains
rather modest, favorable deep-layer shear and proximity to low-level
vorticity in the vicinity of a surface low has helped to increase
tornado potential, and some tornado threat may spread across a
larger portion of southwest WI through early evening, where some
modest airmass recovery has occurred. A Tornado Watch was recently
issued in order to address the short-term tornado threat. Isolated
hail and damaging wind also remain possible.
..Dean.. 06/17/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MKX...DVN...ARX...
LAT...LON 43069104 43269065 43279013 43028970 42728970 42428985
42449025 42479053 42549074 42629096 42739122 42909125
43069104
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0304 PM CDT Wed Jun 17 2026
Valid 172000Z - 181200Z
...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
ILLINOIS AND INDIANA...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHEASTERN LOUISIANA AND SOUTHERN MISSISSIPPI...
...SUMMARY...
Numerous severe thunderstorms remain likely this afternoon into
tonight, with the peak threat centered over Illinois and Indiana.
Intense tornadoes, swaths of damaging gusts over 75 mph and damaging
wind-driven large hail will all be possible.
...20z Update...
An extremely complicated forecast scenario will continue this
afternoon in the wake of a persistent morning convective cluster. An
anomalously strong upper trough and jet are still forecast to move
over parts of the Midwest and Great Lakes this afternoon and
evening. This will support renewed convective development near the
trailing outflow from the morning cluster over the Midwest and along
the synoptic cold front from northeast MO into parts of KS and far
northern OK.
Rapid modification of the air mass along and north of the trailing
outflow boundary/effective warm front still appears plausible given
1-2 mb/hr pressure falls, ongoing low-level moisture advection and
strong heating ahead of the deepening surface cyclone. A focused
mesoscale corridor of strong to intense tornado potential remains
evident from east of St Louis, MO, across south-central IL and into
west-central IN, where RAP soundings show 1000-2000 J/kg of MLCAPE
and exceptionally strong low and mid-level shear with ESRH upwards
of 400-600 m2/s2. The primary uncertainty remains the development
and maintenance of supercells in the wake of the MCS. CAM guidance
remains insistent on a few intense supercells organizing in this
corridor from late afternoon into the evening with a risk for strong
tornadoes, large hail and damaging winds. The threat may persist
into portions of eastern IN, KY and western OH tonight.
Across central MO into KS and OK, a very unstable and moderately
sheared air mass (18z TOP/SGF RAOBS) will promote rapid supercell
development in the next couple of hours along and ahead of the
sagging cold front. Large to very large hail, damaging winds and
tornadoes are possible. As large-scale forcing for ascent moves away
this evening, storm coverage should slowly diminish, though the more
intense supercells may linger well into the evening with an all
hazards risk.
Primary changes to the outlook were to remove northern portions of
the ENH and MDT risk areas where substantial air mass recovery is
unlikely. Wind probabilities were increased on the southern end near
the OH River to account for clustering of expected upstream
development.
Elsewhere, minor changes were made to trim probabilities behind the
cold front. See the previous discussion for additional information.
..Lyons.. 06/17/2026
.PREV DISCUSSION... /ISSUED 1128 AM CDT Wed Jun 17 2026/
...MO/IL/IN...
An intense and fast-moving shortwave trough continues to approach
the Midwest today, with an associated 90+ knot mid level jet
streaking across the region. A very strong southerly low-level jet
precedes this trough, and has resulted in widespread thunderstorms
over central IL. The effects of this early convection will be
important to the mesoscale details of where the main risk of severe
storms will develop later today.
The primary outflow boundary from ongoing storms currently extends
from extreme northeast MO into south-central IL, and continues to
sag southward. Strong heating is occurring to the south of the
boundary, and given the intense low-level flow, some northward
return is expected. However, it appears unlikely to substantially
destabilize as far north as earlier forecasts. The zone in vicinity
of the boundary will become very unstable by mid-late afternoon,
with forecast soundings continuing to show impressive shear values
and hodograph structures suggestive of tornadic supercell potential.
Very large hail and damaging winds will also be possible with this
activity as it tracks quickly eastward into central IN. Strong
tornadoes are possible.
By mid-evening, a line of severe storms will likely extend from
central MO into southern IN, with damaging winds becoming the
primary threat.
...Southeast MN...
A small area of heating/destabilization has developed near the
surface low over southern MN. Cold temperatures aloft and strong
deep-layer shear suggests a threat of a few severe storms capable of
hail and gusty/damaging winds this afternoon.
...LA/MS...
Tropical Storm Arthur will track northward and affect LA and
southern MS tonight. A zone of strong southerly low-level winds to
the east of the circulation will result in some concern for
overnight and pre-dawn tornadoes across southeast LA into far
southern MS.
...Southern AZ/NM...
Scattered afternoon and evening thunderstorms are expected across
southeast AZ and southwest NM. Strong heating and ample instability
will pose a risk of damaging wind gusts in the strongest cells.
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 PM CDT Wed Jun 17 2026
Valid 191200Z - 201200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE
ARKLATEX INTO THE SOUTHEAST...
...SUMMARY...
Isolated strong thunderstorms may produce damaging wind gusts across
the ArkLaTex into portions of the Gulf Coast states/Southeast on
Friday.
...ArkLaTex into the Southeast...
The stalled cold front will provide a focus for renewed convective
development during the afternoon. A potential MCV in North Texas may
drift eastward and promote afternoon convection. Otherwise, strong
heating of a low/mid 70s F dewpoint airmass south of the boundary
will promote moderate to strong buoyancy (2500-3500 J/kg MLCAPE).
Deep-layer flow will be weak, but strong water-loaded downdrafts
will be capable of damaging wind gusts.
...Upper Mississippi Valley...
A compact, strong shortwave trough will move through the northern
Plains into the Upper Mississippi Valley during the afternoon. Given
the short wavelength between the upper trough in the Northeast and
this compact system, moisture return will be somewhat limited
(dewpoints in the mid to perhaps upper 50s F). Temperatures aloft,
however, will be quite cold (-18 to -20 C at 500 mb). Widely
scattered convection appears probable ahead of the shortwave trough
along and near a weak surface trough. Storms appear they will be
relatively low topped. Given the limited moisture/buoyancy, small
hail is possible, but potential for large hail is too low for
probabilities.
..Wendt.. 06/17/2026
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0239 PM CDT Wed Jun 17 2026
Valid 181200Z - 191200Z
...Afternoon Update...
An Isolated Dry Thunderstorm risk area has been introduced across
the central-northern Sierra for Day 2/Thursday. As the upper trough
moves onshore, daytime mixing and resultant sufficient instability
(alongside orographic ascent) amid a dry sub-cloud layer will
promote dry thunderstorm development where dry/receptive fuels
exist. Along the Sierra, forecast soundings depict PWATs ranging
from 0.5-0.8" and robust MUCAPE up to 800 J/Kg. Given an antecedent
ridging pattern with above normal temperatures and dry conditions,
fuels have become increasingly receptive, as indicated by recent
fire starts across the region. Depending on the timing of storm
initiation and any subsequent outflow interactions, thunderstorms
could persist through the overnight hours.
Elevated subtropical moisture will overspread southeastern AZ into
southern NM tomorrow afternoon as a cold front draws near the
central NM mountain chain. Afternoon heating and resultant
instability will support thunderstorm development along the Gila
region into the AZ White Mountains. Forecast PWATs of 0.5-0.8" and
LCLs exceeding 3 km may reduce precipitation efficiency, raising a
concern for some lightning ignitions where dry fuels exist.
See the previous discussion for more information.
..Elizalde-Garcia.. 06/17/2026
.PREV DISCUSSION... /ISSUED 0159 AM CDT Wed Jun 17 2026/
...Synopsis...
A large-scale ridge will re-build over the Southwest into the Great
Basin on Thursday, where a warm/dry air mass will remain in place.
As a result, deep-layer flow will be weaker across the region
compared to prior days, reducing surface wind speeds and the overall
fire-weather risk. However, locally elevated fire-weather conditions
will still be possible within terrain-favored/wind-prone areas
across the Great Basin into the central/southern Rockies during the
afternoon.
...Dry Thunderstorms - Sierra...
Over the Sierra and vicinity, a midlevel trough will begin to
impinge on the large-scale ridge, aiding in thunderstorm development
over the higher terrain during the afternoon. Inverted-V profiles
will favor high-based, mixed wet-dry storms. These storms atop dry
fuels may pose some concern for lightning-induced ignitions.
However, the overall risk appears too localized/limited for Dry
Thunderstorm highlights at this time.
...Central NC and vicinity...
Around 15-20 mph sustained southwesterly surface winds will develop
across the area ahead of an approaching cold front from the west.
These breezy/gusty winds will overlap marginally low RH (around
35-40 percent), and given a lack of rainfall over central NC,
locally elevated fire-weather conditions are possible.
...Please see www.spc.noaa.gov/fire for graphic product...
SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0452 PM CDT Wed Jun 17 2026
Valid 191200Z - 251200Z
...Synopsis...
On Day 3/Friday, an upper low will transition east of Atlantic
Canada as a secondary low atop central-Manitoba gradually follows
behind. This pattern should facilitate expansive troughing to
persist over the Northeast into early next week, sending a series of
cold fronts and multiple rounds of precipitation through the eastern
CONUS. An upper ridge will break down over the West on Day
2/Thursday, initiating several days of dry thunderstorm potential
across portions of the Sierra and upper Great Basin. In addition,
dry and breezy conditions with above normal temperatures (and
resultant dry fuels) will support expansive fire concerns through
Day 4/Saturday. The upper trough will lose its amplitude as it
traverses the Great Plains, transitioning the western CONUS to
somewhat zonal flow aloft. While predictability is low, extended
guidance exhibits increasing potential for ridging to build back
across the Intermountain West, bringing warm and dry conditions back
into the region early next week.
...Days 3-4/Friday-Saturday - Parts of the Pacific Northwest, Sierra
Nevada, and Great Basin...
As upper-level troughing moves onshore, surging mid-level moisture
and synoptic scale forcing will bring increased chances for
thunderstorms. Given preceding days of warm and dry conditions and
coincident curing fuels, the isolated nature of thunderstorm
development could pose a threat for lightning ignitions across a
very dry environment. Fast storm motions, high cloud bases, and
locally breezy conditions support 10% Dry Thunderstorm probabilities
on Day 3/Friday, and again on Day 4/Saturday as the trough shifts
eastward. Spatial extent of the aforementioned risk areas may
fluctuate as guidance is better resolved in future outlook cycles.
Increasing southerly to westerly flow across the Southwest will
transport very dry air and breezy conditions amid recently receptive
fuels, promoting continued fire concerns in the Great Basin through
the weekend. 40% Critical probabilities have been maintained on Days
3-4/Friday-Saturday to account for this threat.
..Elizalde-Garcia.. 06/17/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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