WW 365 TORNADO IN 212145Z - 220400Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 365
NWS Storm Prediction Center Norman OK
545 PM EDT Sun Jun 21 2026
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Central and Southern Indiana
* Effective this Sunday afternoon from 545 PM until Midnight EDT.
* Primary threats include...
A couple intense tornadoes possible
Scattered damaging wind gusts to 70 mph possible
Isolated large hail events to 1 inch in diameter possible
SUMMARY...A cluster of severe thunderstorms with embedded supercells
will likely move east into the Watch area this evening. A couple of
supercells will pose a risk for tornadoes, including the possibility
of a strong tornado. In addition to the tornado threat, scattered
severe gusts 60 to 70 mph are possible.
The tornado watch area is approximately along and 45 statute miles
north and south of a line from 35 miles west of Bloomington IN to 60
miles southeast of Indianapolis IN. 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 363...WW 364...
AVIATION...Tornadoes and 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 450. Mean
storm motion vector 25030.
...Smith
WW 364 SEVERE TSTM CO KS NE 211845Z - 220200Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 364
NWS Storm Prediction Center Norman OK
1245 PM MDT Sun Jun 21 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Northeast Colorado
Northwest Kansas
Western Nebraska
* Effective this Sunday afternoon and evening from 1245 PM until
800 PM MDT.
* Primary threats include...
Scattered large hail likely with isolated very large hail events
to 3 inches in diameter possible
Scattered damaging wind gusts to 70 mph possible
SUMMARY...Thunderstorms will develop and intensify over the watch
area this afternoon, spreading southeastward with time. Large to
very large hail is the main concern, but there will be an increasing
risk of damaging winds this evening.
The severe thunderstorm watch area is approximately along and 60
statute miles east and west of a line from 35 miles northwest of
Mullen NE to 50 miles south of Goodland KS. For a complete depiction
of the watch see the associated watch outline update (WOUS64 KWNS
WOU4).
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 363...
AVIATION...A few severe thunderstorms with hail surface and aloft to
3 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
30030.
...Hart
WW 363 TORNADO IL IN MO 211830Z - 220200Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 363
NWS Storm Prediction Center Norman OK
130 PM CDT Sun Jun 21 2026
The NWS Storm Prediction Center has issued a
* Tornado Watch for portions of
Central and Southern Illinois
Southwest Indiana
Southeast Missouri
* Effective this Sunday afternoon and evening from 130 PM until
900 PM CDT.
* Primary threats include...
A few tornadoes likely with a couple intense tornadoes possible
Scattered damaging wind gusts to 70 mph likely
Isolated large hail events to 1.5 inches in diameter possible
SUMMARY...Thunderstorms will intensify this afternoon across the
watch area, with a few supercells expected. Damaging winds and
tornadoes are possible in the strongest cells.
The tornado watch area is approximately along and 50 statute miles
north and south of a line from 35 miles southwest of Scott Afb IL to
30 miles south of Terre Haute IN. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU3).
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.
&&
AVIATION...Tornadoes and 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 500. Mean
storm motion vector 26030.
...Hart
WW 0365 Status Updates
STATUS FOR WATCH 0365 HAS NOT BEEN ISSUED YET
WW 0364 Status Updates
STATUS REPORT ON WW 364
THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.
..LYONS..06/21/26
ATTN...WFO...GLD...BOU...LBF...
STATUS REPORT FOR WS 364
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
COC017-063-073-095-115-121-125-212240-
CO
. COLORADO COUNTIES INCLUDED ARE
CHEYENNE KIT CARSON LINCOLN
PHILLIPS SEDGWICK WASHINGTON
YUMA
KSC023-039-063-065-071-109-137-153-179-181-193-199-203-212240-
KS
. KANSAS COUNTIES INCLUDED ARE
CHEYENNE DECATUR GOVE
GRAHAM GREELEY LOGAN
NORTON RAWLINS SHERIDAN
SHERMAN THOMAS WALLACE
WICHITA
NEC005-029-031-049-057-063-069-075-085-087-091-101-111-113-117-
135-145-161-171-212240-
NE
WW 0363 Status Updates
STATUS REPORT ON WW 363
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 SSE STL TO
20 SSW DNV.
..LYONS..06/21/26
ATTN...WFO...LSX...ILX...PAH...IND...
STATUS REPORT FOR WT 363
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
ILC005-023-025-027-029-033-035-041-045-047-049-051-055-059-065-
077-079-081-101-119-121-133-139-145-157-159-163-165-173-185-189-
191-193-199-212240-
IL
. ILLINOIS COUNTIES INCLUDED ARE
BOND CLARK CLAY
CLINTON COLES CRAWFORD
CUMBERLAND DOUGLAS EDGAR
EDWARDS EFFINGHAM FAYETTE
FRANKLIN GALLATIN HAMILTON
JACKSON JASPER JEFFERSON
LAWRENCE MADISON MARION
MONROE MOULTRIE PERRY
RANDOLPH RICHLAND ST. CLAIR
SALINE SHELBY WABASH
WASHINGTON WAYNE WHITE
WILLIAMSON
INC051-083-125-129-153-167-212240-
IN
. INDIANA COUNTIES INCLUDED ARE
MD 1233 CONCERNING SEVERE POTENTIAL...WATCH NEEDED SOON FOR SOUTHERN AND CENTRAL INDIANA
Mesoscale Discussion 1233
NWS Storm Prediction Center Norman OK
0423 PM CDT Sun Jun 21 2026
Areas affected...Southern and Central Indiana
Concerning...Severe potential...Watch needed soon
Valid 212123Z - 212300Z
Probability of Watch Issuance...95 percent
SUMMARY...The tornado threat is increasing across portions of
southern Indiana as thunderstorms with a history of producing
tornadoes across southern Illinois move east into the area. A
tornado watch will be needed soon.
DISCUSSION...Several supercells with a history of producing
tornadoes have developed this afternoon across portions of southern
Illinois in association with a convectively augmented vorticity
maximum moving east within zonal mid-level flow. Ahead of these
supercells, a surface boundary is slowly lifting northward across
portions of Indiana. To the south of this boundary, surface
dewpoints have risen into the 60Fs to low 70Fs contributing to
MLCAPE values between 500-1000 J/kg. Along the boundary easterly
low-level flow will maximize storm-relative helicity, as indicated
by the Indianapolis VAD (KIND) which suggests around 300 m2/s2. The
result will be a continued tornado threat this evening across
portions of southern and central Indiana and a tornado watch will be
required soon.
..Marsh/Smith.. 06/21/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ILN...LMK...IND...ILX...
LAT...LON 39798785 40148739 40348673 40268550 39928483 39418459
38868482 38618545 38558629 38628775 39798785
MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN
MD 1232 CONCERNING SEVERE THUNDERSTORM WATCH 364... FOR EASTERN COLORADO...SOUTHWEST NEBRASKA...AND NORTHWEST KANSAS
Mesoscale Discussion 1232
NWS Storm Prediction Center Norman OK
0333 PM CDT Sun Jun 21 2026
Areas affected...Eastern Colorado...southwest Nebraska...and
northwest Kansas
Concerning...Severe Thunderstorm Watch 364...
Valid 212033Z - 212230Z
The severe weather threat for Severe Thunderstorm Watch 364
continues.
SUMMARY...The threat for large hail continues across eastern
Colorado and into southwest Nebraska. However, upscale growth into
an MCS is anticipated through early evening with an attendant uptick
in severe wind potential across northwest Kansas.
DISCUSSION...Multiple instances of 1.0 to 1.75 inch hail have been
noted across the central High Plains over the past couple of hours
as loosely organized splitting supercells continue to develop and
mature. Based on recent radar trends, these cells are likely
sufficiently spaced to maintain mostly discrete storm modes for the
next hour or two, which will maintain the threat for large hail -
especially along/near the eastern CO border where thermodynamic
conditions are most favorable for very large (2 inch) hail.
Beyond the next couple of hours, the combination of deviant storm
motions and colliding outflow boundaries (at least one of which is
already noted in reflectivity data from KFTG) will promote storm
interactions and gradual upscale growth into one or more clusters.
As this occurs, cold pool amalgamation/intensification within an
environment featuring steep low-level lapse rates should promote
increasing potential for severe wind gusts, including occasional
gusts upwards of 75 mph. Per time-lagged HRRR/RRFS ensembles, this
transition appears most likely to occur across east-central CO and
into northwest KS during the 22-00 UTC time frame.
..Moore.. 06/21/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GID...LBF...GLD...PUB...BOU...CYS...
LAT...LON 39040422 39320437 39570420 41360235 41620200 41670164
41610122 40830006 40539992 40200000 39910028 38990125
38690191 38570245 38530283 38530318 38590353 39040422
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0257 PM CDT Sun Jun 21 2026
Valid 212000Z - 221200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF
THE CENTRAL HIGH PLAINS TO THE MISSISSIPPI AND LOWER OHIO VALLEYS...
...SUMMARY...
Scattered severe thunderstorms should occur from the central High
Plains into the mid Mississippi and lower Ohio Valleys, mainly this
afternoon into tonight. Large to very large hail, severe/damaging
winds (some 75+ mph), and tornadoes will all be possible. Some
potential for strong tornadoes may develop across parts of Illinois,
and Indiana during the afternoon and evening.
...20z Update Mid MS Valley and lower OH Valley...
Minimal changes were made to the prior outlook given the latest
observational trends. Several clusters of strong thunderstorms are
ongoing ahead of an MCV across the mid MS Valley. An observed messy
convective mode should persist with a mix of bowing structures and
transient supercells likely ahead of the MCV, and near the effective
warm front from eastern IL into IN. Additional storm development is
also possible behind the MCV along the remnant boundary into MO and
eastern KS. This will support a risk for damaging gusts and perhaps
a couple of tornadoes where low-level flow is backed and hodographs
are larger. Eventually upscale growth into one or more bowing
clusters is likely later this evening/overnight into the OH valley
with a continued risk for damaging gusts and embedded tornadoes.
...KS/OK this evening/tonight...
Severe storm development appears probable along the modified
trailing outflow across northwest OK and southwest KS this afternoon
into this evening. Sufficient vertical shear exists for supercells
and organized clusters. With large buoyancy and steep low/mid-level
lapse rates, large hail is likely with these strong updrafts. A
brief tornado or two is also possible, owing to storm interactions
and ambient vertical vorticity along the outflow boundary.
Damaging wind potential will likely increase with storm
consolidation, though the more cellular initial mode suggests this
maybe somewhat gradual. These storms, and additional convection
originating further north from the central High Plains, should
persist overnight into central and southern OK, reaching the Red
River Valley by 12z tomorrow morning with isolated severe potential.
..Lyons.. 06/21/2026
.PREV DISCUSSION... /ISSUED 1110 AM CDT Sun Jun 21 2026/
...MO/IL/IN/KY...
A long-lived band of thunderstorms currently extends from
east-central MO into southwest MO/northeast OK. This activity is
tracking into a region of increasingly warm/moist air where
dewpoints are rising to near 70F and breaks in the clouds are
contributing to moderate CAPE values. All CAM guidance suggests
that storms along the line will intensify this afternoon and track
eastward across southern IL/southern IN and northern KY. Low-level
shear is quite strong, but somewhat veered. This increases
uncertainty of storm mode between discrete supercells or bowing
structures. It appears there will be a period of risk early in the
event for tornadic supercells, followed by multiple linear storm
segments capable of damaging wind gusts. Storms may remain severe
as far east as southern OH and eastern KY overnight. Refer to MD
#1228 for further short-term details.
...MO/KS/OK/AR...
In the wake of the aforementioned convection, an outflow boundary
extends southwestward into central OK. Rapid clearing is occurring
north of the boundary, where residual moisture and steep lapse rates
will quickly destabilize the area. Scattered thunderstorms are
expected to form by late afternoon in this zone and track slowly
southeastward. Sufficient deep-layer shear and high CAPE will
promote the risk of a few supercells capable of large hail and
damaging winds. A tornado or two might also occur.
...NE/CO/KS...
Low clouds are eroding across the NE Panhandle southward into
eastern CO/western KS, where rapid afternoon destabilization should
occur. A weak shortwave trough over eastern WY will rotate into the
region this afternoon, helping to initiate scattered thunderstorms.
Supercells capable of very large hail appear possible, tracking
southeastward across the risk area through mid-evening.
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1221 PM CDT Sun Jun 21 2026
Valid 221200Z - 231200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE MID-ATLANTIC INTO SOUTHERN APPALACHIANS...AND OVER PARTS OF THE
NORTHERN AND CENTRAL HIGH PLAINS...
...SUMMARY...
Scattered severe storms appear possible across portions of the
Mid-Atlantic into the Southern Appalachians Monday afternoon and
evening. Widely scattered severe storms are expected across the
northern and central High Plains, with more isolated severe weather
possible from the southern Plains into the lower Mississippi Valley.
...Synopsis...
A series of perturbations, embedded within broadly cyclonic
mid-level flow, will progress eastward to the Atlantic Coast, to the
south of an upper low tracking from eastern Ontario into southern
Quebec. Farther west, separate vorticity maxima will overspread the
northern and central High Plains, in tandem with a belt of
strengthening mid-level winds.
In the lower levels, a 40-50 kt low-level jet (LLJ) is forecast to
migrate from the Allegheny Plateau into the lower Hudson and DE
River Valleys Monday afternoon, ahead of a surface low developing
toward those same areas. Meanwhile, a trailing cold front will
advance south through the central Appalachians, TN Valley, and Ozark
Plateau, with the western extension of the boundary linking with a
secondary low over western TX. Elsewhere, a lee cyclone is expected
to deepen over eastern WY, along a weak front settling southeast
through the northern High Plains.
...Mid-Atlantic into the southern Appalachians...
12Z CAM guidance is in relatively good agreement in depicting the
remnants of an overnight (Sunday night/early Monday morning) MCS
overspreading NY and PA, within a zone of warm air and moisture
advection occurring with the terminus of the LLJ. To the
south/southeast of that convection across the lower Hudson and DE
River Valleys, modest air mass destabilization is expected, with
comparably stronger instability with southward extent into the
central/southern Appalachians and Piedmont. Deep-layer shear is
forecast to strengthen through the day as a belt of 40-50 kt winds
at 500 mb overspreads the region from the west.
Thunderstorms are expected to increase in areal coverage and
intensity during the afternoon from the vicinity of the outflow or
differential heating boundary in eastern PA south/southwest into the
southern Appalachians and Piedmont. Damaging winds will be the
primary hazard owing to steepening low-level lapse rates and high
moisture content, which will enhance wet-microburst processes. A
relatively narrow corridor of potentially greater tornado potential
may materialize from the DelMarVa into the DE River Valley, where
stronger low-level shear is forecast. However, given uncertainties
in the degree of air mass destabilization in the northern extent of
that area, the 2% unconditional tornado probability will be
maintained. A separate area of tornado potential may materialize
Monday afternoon across parts of the southern Appalachians within
the southwest extension of the LLJ, where a number of the 12Z CAMs
indicate updraft-helicity swaths embedded within a linear complex of
storms.
...Northern and central High Plains...
The deepening lee cyclone will enhance the flux of an increasingly
moist low-level air mass into the high terrain, beneath a plume of
steep mid-level lapse rates, supporting moderate afternoon
instability. Greatest storm coverage is expected across portions of
eastern MT and western ND Monday afternoon within the northern
extent of the instability axis, where the strongest forcing for
ascent is expected. Weaker forcing with southward extent is expected
to lead to more widely spaced storms in eastern WY and CO. Here,
comparatively stronger instability and vertical shear will support
supercells capable of large to very large hail and perhaps a brief
tornado or two during the afternoon and evening hours.
...Southern Plains...
Areas of storms ongoing Monday morning across parts of the Red River
Valley into the ArkLaTex region are expected to gradually weaken by
midday, owing to rising mid-level heights across the region. In the
wake of that activity, moderate to strong instability is forecast by
afternoon in the vicinity of the stalled synoptic front and any
remnant outflow boundaries. However, considerable uncertainty
remains in surface-based storm development given the absence of
appreciable forcing for ascent. As such, the low unconditional
probabilities will be maintained with this forecast update. On the
condition surface-based storms develop and are sustained, the
parameter space would support intense supercells capable of large to
very large hail and some tornado threat.
..Mead.. 06/21/2026
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0216 PM CDT Sun Jun 21 2026
Valid 231200Z - 241200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE CENTRAL
HIGH PLAINS...
...SUMMARY...
Scattered severe storms are expected across the central High Plains
on Tuesday with isolated severe storms possible into the Upper
Mississippi Valley. Large to very large hail and damaging wind gusts
will be the primary threats.
...Synopsis...
An upper low initially over Saskatchewan/Manitoba will drift
southeast to along the international border with an attending belt
of 40-50+ kt mid-level flow forecast across the northern and central
Plains into the upper Midwest. Farther east, a short-wave trough
trailing an upper low over Ontario will move through the
Mid-Atlantic. In the low levels, an area of low pressure is forecast
to develop from the northern Plains into upper MS Valley with a
trailing boundary extending southwest into the central High Plains.
Elsewhere, a cold front will move off the Mid-Atlantic Coast with
the trailing extension of the boundary moving into the Southeast.
...Central and southern High Plains...
Despite the potential for early-day storms across portions of NE,
TX, and OK, the EML is expected to remain intact over the central
High Plains. When coupled with an increasingly moist upslope air
mass in the vicinity of the front, moderate to strong instability is
forecast by afternoon. Diurnally enhanced thunderstorms are expected
to form along favored terrain and pre-existing surface boundaries
amidst a kinematic environment featuring vertically veering winds
with height with sufficient vertical shear to support supercells
capable of large to very large hail. The nocturnal strengthening of
a low-level jet over western parts of KS, OK, and TX may favor
upscale growth of storms into a forward-propagating MCS Tuesday
evening with an associated increase in severe-wind-gust potential.
...Upper Mississippi Valley into the mid Missouri Valley...
Latest model data are in good agreement in depicting areas of
showers and storms lingering through much of the day across the
pre-frontal warm sector. Vertical shear is forecast to be
sufficiently strong to support organized storm modes, especially
across the upper MS Valley. However, the potential for clouds and
precipitation to limit air mass destabilization leads to uncertainty
in the extent of the severe-weather threat. As such, the low
severe-weather probabilities will be maintained with this forecast
update.
...Middle and southern Atlantic Coast into the central Gulf Coast
States...
A few strong storms capable of gusty winds appear possible Tuesday
afternoon along and ahead of the synoptic front. While poor
low/mid-level lapse rates are expected to limit a more robust
damaging-wind threat, low severe-weather probabilities may
eventually be added once details in storm evolution become more
clear.
..Mead.. 06/21/2026
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0133 PM CDT Sun Jun 21 2026
Valid 221200Z - 231200Z
The Elevated area over the larger Four Corners region was expanded
slightly to include more of central CO. This change was made in
agreement with the latest forecast guidance depicting southwest
winds of 10-20 mph amid afternoon RHs of 5-15% - even up to
elevations of 10,000 feet - on Day 2/Monday. The forecast remains on
track across other areas as previously mentioned.
..Stearns.. 06/21/2026
.PREV DISCUSSION... /ISSUED 0139 AM CDT Sun Jun 21 2026/
...Synopsis...
Similar to Day 1, zonal mid-level flow with embedded impulses will
characterize the upper-air pattern across the CONUS tomorrow
(Monday). Surface troughing will develop across the Interior West by
the afternoon hours, resulting in a broad area of dry and breezy
conditions across the southern Great Basin into the Four Corners
region. 15+ mph sustained westerly surface winds will coincide with
5-15 percent RH atop dry fuels, warranting the introduction of
Elevated highlights. Similarly, Elevated highlights were also
introduced for another afternoon of channeled flow across the Snake
River Plain, where 15+ mph sustained westerly surface winds and 15
percent RH will overspread dry fuels for several hours.
...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
0457 PM CDT Sun Jun 21 2026
Valid 231200Z - 291200Z
...Synopsis...
A broad ridge centered over the Southwest US will dominate much of
the Intermountain West's weather as the week begins. This pattern
will reinforce warmer-than-normal and dry conditions, continuing to
accelerate fuel desiccation across the region. This high centered
near the AZ/NM borders will persist long enough that moisture will
begin to advect north and eastward over the larger Four Corners
region. Conversely, expansive troughing will dominate the Northeast,
sending periodic cold fronts and widespread precipitation across the
eastern United States to suppress regional fire threats there. The
consensus among the latest long-term forecast guidance is that this
pattern will be temporary with the Southwest high expected to weaken
by Day 6/Friday as a large trough approaches the Pacific Northwest.
As this high breaks down, potentially significant fire weather
concerns will be possible Day 6/Friday through the weekend.
...Day 3/Tuesday...
As high pressure builds over the Southwest, hot and dry (RHs at
5-15%) surface conditions will promote deep boundary layer mixing,
contributing to increased west/southwesterly surface winds of 15-25
mph. As such, a 70 percent probability of Critical wind/RH area
(with the highest concern for the strongest winds) was introduced
over far southern UT and northwest AZ. The existing area of 40
percent probability of Critical wind/RH was expanded over a more
widespread area from southern NV to east of the Four Corners.
...Day 4/Wednesday and Day 5/Thursday...
Persistent high pressure over the Southwest will eventually lead to
increasing moisture wrapped in from the Gulf of California. It
appears that this moisture will begin to reach eastern AZ, western
NM, and far southwest CO on Day 4/Wednesday, followed by southern UT
and western CO on Day 5/Thursday. As is typical with this pattern,
hot and dry air at the surface will lag increasing moisture aloft,
leading to high-based thunderstorms. Expect adjustments in
time/space with future forecast issuances as the timing and
placement of this potential moisture becomes more clear. While some
uncertainty remains as to how much rainfall could accumulate, daily
precipitation is expected to remain below 1/10 inch outside of
particularly intense storms and generally under 1/4 inch where not
orographically enhanced. Additionally, an area of 40 percent
probability of Critical wind/RH was introduced over eastern NV where
hot and dry surface conditions will combine with both southwesterly
flow closer to the high pressure and a tightened surface pressure
gradient from the approaching system to the northwest.
...Day 6/Friday through Day 8/Sunday...
The aforementioned trough moving over the Pacific Northwest will dig
southward as it comes onshore. A cold front will accompany this
system as temperatures fall below normal for this time of year
across much of the northwest third of the country. The threat will
begin to be widespread over much of the Intermountain West on Day
6/Friday as the area is squeezed between the existing ridge and
incoming trough. However, as the cold front progresses southeastward
as the weekend progresses, sustained surface winds will have the
potential to exceed 20-30 mph over portions of northern AZ, much of
UT, and western CO. One question that remains is how far south will
the trough dig...determining how strong the winds do become over the
larger Four Corners region with recent lightning activity earlier in
the forecast period. This pattern has potential to cause major fire
weather concerns over a region of the country where dead fuels
currently sit near or above 95th percentile ERCs.
..Stearns.. 06/21/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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