WW 639 SEVERE TSTM IA MN NE SD 012050Z - 020400Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 639
NWS Storm Prediction Center Norman OK
350 PM CDT Tue Sep 1 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Far Northwest Iowa
Far Southwest Minnesota
North-Central and Northeast Nebraska
Southeast South Dakota
* Effective this Tuesday afternoon and evening from 350 PM until
1100 PM CDT.
* Primary threats include...
Scattered damaging winds likely with isolated significant gusts
to 80 mph possible
Scattered large hail likely with isolated very large hail events
to 2 inches in diameter possible
A tornado or two possible
SUMMARY...Initial supercells will likely pose a threat for large
hail up to 2 inches in diameter. A tornado or two may also occur
with any sustained supercell, especially if thunderstorms can remain
at least semi-discrete through early evening as low-level shear
increases. Otherwise, a bowing cluster is expected to eventually
develop and pose a greater threat for severe/damaging winds up to
70-80 mph as it tracks generally eastward across southeast South
Dakota/northeast Nebraska and vicinity.
The severe thunderstorm watch area is approximately along and 60
statute miles north and south of a line from 60 miles northwest of
Burwell NE to 35 miles east southeast of Sioux Falls SD. 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 638...
AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 70 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
25030.
...Gleason
WW 638 SEVERE TSTM DE MD NJ NY PA CW 012035Z - 020400Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 638
NWS Storm Prediction Center Norman OK
435 PM EDT Tue Sep 1 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
Delaware
Northeast Maryland
New Jersey
Southern New York
Central and Eastern Pennsylvania
Coastal Waters
* Effective this Tuesday afternoon from 435 PM until Midnight
EDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
Scattered large hail events to 1.5 inches in diameter possible
A tornado or two possible
SUMMARY...Supercell thunderstorms should pose a threat for large
hail this afternoon as they track east-southeastward across the
northern Mid-Atlantic. The threat for scattered severe/damaging
winds should increase this evening as one or more clusters develops.
A tornado or two may also occur with any sustained supercell.
The severe thunderstorm watch area is approximately along and 80
statute miles east and west of a line from 50 miles north northwest
of Wilkesbarre PA to 35 miles east southeast of Dover DE. 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.
&&
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 500. Mean storm motion vector
31025.
...Gleason
WW 0639 Status Updates
STATUS FOR WATCH 0639 HAS NOT BEEN ISSUED YET
WW 0638 Status Updates
STATUS FOR WATCH 0638 HAS NOT BEEN ISSUED YET
MD 2186 CONCERNING SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY FOR NORTH-CENTRAL TO NORTHEAST NEBRASKA INTO SOUTH-CENTRAL TO SOUTHEAST SOUTH DAKOTA.
Mesoscale Discussion 2186
NWS Storm Prediction Center Norman OK
0317 PM CDT Tue Sep 01 2026
Areas affected...north-central to northeast Nebraska into
south-central to southeast South Dakota.
Concerning...Severe potential...Severe Thunderstorm Watch likely
Valid 012017Z - 012215Z
Probability of Watch Issuance...80 percent
SUMMARY...A severe thunderstorm watch will likely be needed this
afternoon/evening across parts of northeast Nebraska and southeast
South Dakota and vicinity.
DISCUSSION...Weak elevated convection has been persistent across
north-central Nebraska for much of the day. Recently, the cu-field
across north-central Nebraska has started to expand, consistent with
the erosion of MLCIN from SPC mesoanalysis. A weak mid-level
shortwave trough, currently across eastern Colorado and the Nebraska
Panhandle, will advance east through the evening with weak ascent
overspreading the uncapped warm sector. In addition, the low-level
jet will strengthen through the evening and into the overnight hours
which will lead to additional ascent across the region. Moderate to
strong instability, combined with 50 to 55 knots of effective shear
will support supercell storm mode initially with some threat for
very large hail and 75+ mph wind gusts. As storms grow upscale, a
more focused corridor of severe wind gusts may develop near the
NE/SD border into the evening.
A severe thunderstorm watch will need to be issued this
afternoon/evening to address this threat.
..Bentley/Gleason.. 09/01/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FSD...OAX...ABR...GID...LBF...UNR...
LAT...LON 42879986 43389982 43939892 44299796 44139717 43749667
42959652 42219686 41459833 41079962 41029994 42370004
42879986
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 1630Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Tue Sep 01 2026
Valid 011630Z - 021200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHERN NEW YORK INTO THE MID-ATLANTIC...AND THE NORTHERN/CENTRAL
PLAINS INTO THE UPPER MIDWEST...
...SUMMARY...
Scattered strong to severe thunderstorms should occur this afternoon
into tonight across parts of the northern/central Plains and Upper
Midwest, and parts of southern New York into the Mid-Atlantic. Large
hail and damaging winds should be the main threats.
...Mid-Atlantic/Southern New York...
A mid/upper-level anticyclone will remain centered over the TN
Valley/Mid-South today, with a mid-level shortwave trough forecast
to move eastward across Ontario through the period. In between these
features, a belt of enhanced west-northwesterly flow will exist
across the Great Lakes into the Mid-Atlantic. Latest surface
observations show a front draped from northwest to southeast across
southern NY/New England, with cloud cover and precipitation ongoing
across these areas. Current expectations are for destabilization to
occur along/south of the front through the afternoon, with modestly
steepened mid-level lapse rates present across MI (reference 12Z
observed APX/DTX soundings) forecast to advect southeastward across
the Mid-Atlantic. Moderate to strong instability will likely develop
by mid afternoon across PA/NJ, with 30-40 kt of deep-layer shear
fostering updraft organization.
While there is still some uncertainty regarding overall convective
development and evolution this afternoon/evening owing to nebulous
large-scale ascent, most high-resolution guidance develops isolated
to widely scattered thunderstorms along/south of the front,
particularly over eastern PA into NJ and vicinity. Supercells with a
severe hail/wind threat will be possible initially, and enough
low-level shear may exist near the front for a tornado or two as
well. Whether convection can grow upscale into one or more clusters
also remains uncertain. But if this occurs, then the threat for
damaging winds may increase late this afternoon into the evening
given the rather favorable environment forecast.
...Northern/Central Plains into the Upper Midwest/Great Lakes...
A mid-level shortwave trough over the northern/central Rockies and
adjacent High Plains this morning will translate northeastward today
over the northern/central Plains. A moist and unstable airmass will
reside along/south of a front forecast to extend generally west to
east across parts of southern SD/northern NE into southern
MN/northern IA. Robust thunderstorm development appears increasingly
likely by 21-23Z across north-central NE as large-scale ascent
preceding the shortwave trough overspreads the destabilizing warm
sector. Latest NAM/RAP forecast soundings across this region show up
to 1500-2500 J/kg of MLCAPE and strong deep-layer shear, which will
likely support supercells initially. With steepened low/mid-level
lapse rates and elongated/nearly straight hodographs at mid levels
depicted, some potential for 2+ inch hail may exist with these
supercells. A tornado or two also appears possible as low-level
shear gradually increases after 02/00Z. With time, a bowing cluster
is expected to develop across eastern SD/northeast NE this evening,
and subsequently track eastward across southern MN/northern IA with
a severe/damaging wind threat overnight. Some risk for damaging
winds and hail may continue into early Wednesday morning across
parts of WI and Lower MI as well.
...Coastal Southeast Texas/Southwest Louisiana...
Tropical Storm Edouard will continue tracking northwestward today,
per latest NHC forecasts. Some enhancement to the low-level wind
field and hodograph is noted on the latest VWP and 15Z special
observed sounding from KLCH. This may support transient updraft
rotation with any cells on the north to northeast side of Edouard's
circulation, and a brief tornado or two may occur this
afternoon/evening across parts of coastal southeast TX/southwest LA
as filtered diurnal heating supports modest destabilization.
..Gleason/Moore.. 09/01/2026
SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0300 PM CDT Tue Sep 01 2026
Valid 012000Z - 021200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
SOUTHERN NEW YORK INTO THE MID-ATLANTIC...AND THE NORTHERN/CENTRAL
PLAINS INTO THE UPPER MIDWEST...
...SUMMARY...
Scattered strong to severe thunderstorms should occur this afternoon
into tonight across parts of the northern/central Plains and Upper
Midwest, and parts of southern New York into the Mid-Atlantic. Large
hail and damaging winds should be the main threats.
...20Z Update...
Only minor changes were made with this update. The MRGL Risk was
expanded slightly southward into northwest KS, where an evolving
storm and additional towering cumulus will pose a risk of isolated
large hail and locally severe gusts -- aided by an elongated
hodograph (around 30 kt of effective shear) and sufficient buoyancy.
In the northern/central Plains, some consideration was given to
adding 30-percent wind probabilities in parts of southeast SD,
northeast NE, and northwest IA. Here, guidance is in good agreement
that an upscale-growing cluster will pose a relatively greater
severe-wind risk. However, given the late expected timing, higher
probabilities were withheld at this time.
For details on the near-term severe risk, see MCDs 2184 and 2185.
..Weinman.. 09/01/2026
.PREV DISCUSSION... /ISSUED 1128 AM CDT Tue Sep 01 2026/
...Mid-Atlantic/Southern New York...
A mid/upper-level anticyclone will remain centered over the TN
Valley/Mid-South today, with a mid-level shortwave trough forecast
to move eastward across Ontario through the period. In between these
features, a belt of enhanced west-northwesterly flow will exist
across the Great Lakes into the Mid-Atlantic. Latest surface
observations show a front draped from northwest to southeast across
southern NY/New England, with cloud cover and precipitation ongoing
across these areas. Current expectations are for destabilization to
occur along/south of the front through the afternoon, with modestly
steepened mid-level lapse rates present across MI (reference 12Z
observed APX/DTX soundings) forecast to advect southeastward across
the Mid-Atlantic. Moderate to strong instability will likely develop
by mid afternoon across PA/NJ, with 30-40 kt of deep-layer shear
fostering updraft organization.
While there is still some uncertainty regarding overall convective
development and evolution this afternoon/evening owing to nebulous
large-scale ascent, most high-resolution guidance develops isolated
to widely scattered thunderstorms along/south of the front,
particularly over eastern PA into NJ and vicinity. Supercells with a
severe hail/wind threat will be possible initially, and enough
low-level shear may exist near the front for a tornado or two as
well. Whether convection can grow upscale into one or more clusters
also remains uncertain. But if this occurs, then the threat for
damaging winds may increase late this afternoon into the evening
given the rather favorable environment forecast.
...Northern/Central Plains into the Upper Midwest/Great Lakes...
A mid-level shortwave trough over the northern/central Rockies and
adjacent High Plains this morning will translate northeastward today
over the northern/central Plains. A moist and unstable airmass will
reside along/south of a front forecast to extend generally west to
east across parts of southern SD/northern NE into southern
MN/northern IA. Robust thunderstorm development appears increasingly
likely by 21-23Z across north-central NE as large-scale ascent
preceding the shortwave trough overspreads the destabilizing warm
sector. Latest NAM/RAP forecast soundings across this region show up
to 1500-2500 J/kg of MLCAPE and strong deep-layer shear, which will
likely support supercells initially. With steepened low/mid-level
lapse rates and elongated/nearly straight hodographs at mid levels
depicted, some potential for 2+ inch hail may exist with these
supercells. A tornado or two also appears possible as low-level
shear gradually increases after 02/00Z. With time, a bowing cluster
is expected to develop across eastern SD/northeast NE this evening,
and subsequently track eastward across southern MN/northern IA with
a severe/damaging wind threat overnight. Some risk for damaging
winds and hail may continue into early Wednesday morning across
parts of WI and Lower MI as well.
...Coastal Southeast Texas/Southwest Louisiana...
Tropical Storm Edouard will continue tracking northwestward today,
per latest NHC forecasts. Some enhancement to the low-level wind
field and hodograph is noted on the latest VWP and 15Z special
observed sounding from KLCH. This may support transient updraft
rotation with any cells on the north to northeast side of Edouard's
circulation, and a brief tornado or two may occur this
afternoon/evening across parts of coastal southeast TX/southwest LA
as filtered diurnal heating supports modest destabilization.
SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1230 PM CDT Tue Sep 01 2026
Valid 021200Z - 031200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE EASTERN
GREAT LAKES INTO MID-ATLANTIC AND OVER THE NORTHERN ROCKIES...
...SUMMARY...
Severe thunderstorms are possible across portions of the eastern
Great Lakes to the Mid-Atlantic Wednesday into Wednesday night.
Damaging wind gusts are the main threat, though some large hail and
a few tornadoes may also occur. Widely scattered severe gusts and
more sporadic occurrences of large hail appear possible from the
northern Rockies into northern High Plains Wednesday afternoon into
night.
...Synopsis...
A belt of 40-50+ kt mid-level winds will spread from the Great Lakes
into the Northeast in tandem with a series of low-amplitude
disturbances. Elsewhere, a negatively tilted shortwave trough and
attending mid-level jet streak will progress through the northern
Rockies Wednesday afternoon and evening. At the surface, the primary
baroclinic zone is expected to extend from low pressure over James
Bay through the Great Lakes and mid MO Valley into the northern High
Plains. A backdoor front/quasi-stationary boundary will reside over
the Mid-Atlantic, the specific location of which will be dictated by
the extent of outflow associated with early-day storms and the
strength of low-level ridging stretching from the Gulf of St.
Lawrence through the Northeast.
...Great Lakes into the Mid-Atlantic...
As alluded to in the synopsis, thunderstorms may be ongoing at 12Z
Wednesday from portions of WI and MI into NY and PA within a zone of
forcing for ascent associated with a lead short-wave trough. The
strongest storms will be capable of isolated occurrences of large
hail and/or damaging winds as they spread east-southeast through the
lower Great Lakes and Mid-Atlantic Wednesday morning. In the wake of
the early-day convection, prevailing west-northwest mid-level flow
will maintain a plume of relatively steep mid-level lapse rates
(e.g., 7 C/km) atop boundary layer dewpoints in the upper 60s to low
70s, yielding MLCAPE upwards of 2000-3000+ J/kg by afternoon from
lower MI into western parts of NY and PA.
Additional thunderstorms are expected during the afternoon from
lower MI through the lower Great Lakes, aided by weak disturbances
aloft and the moderate to strong instability forecast across the
warm sector. The presence of 35-45 kt of effective bulk shear will
support organized storm modes including supercells and bowing
structures capable of large hail potentially approaching two inches
and damaging wind gusts into Wednesday night. Tornado potential will
be conditional on storm mode; however, the models do indicate
stronger low-level winds and resultant larger SRH developing from
southwest ON into NY and PA Wednesday afternoon into evening, where
the greatest potential for a few tornadoes will exist.
...Northern Rockies into northern High Plains...
The presence of steep low/mid-level lapse rates and forcing for
ascent attendant to the short-wave trough are expected to foster an
increase in thunderstorms over western MT Wednesday afternoon amidst
a kinematic environment featuring around 30 kt of southerly
deep-layer shear. NAM and RAP-based forecast soundings indicate the
presence of a relatively deep, well-mixed boundary layer, which will
enhance severe-wind-gust potential, especially as storms merge into
clusters. Given the strength of the short-wave trough and consistent
model signal for scattered storms in a favorable thermodynamic
environment, an upgrade to level-2/Slight Risk was included in this
forecast.
Additional storms appear possible across portions of eastern MT into
western ND Wednesday evening within a zone of warm advection along a
nocturnally strengthening low-level jet. Isolated occurrences of
large hail appear to be the primary hazard with those storms.
...Mid MO Valley into IA and southern MN...
Neutral to slight mid-level height rises are forecast across the
region Wednesday afternoon into night with the nebulous forcing for
ascent leading to uncertainty in whether storms will develop near
the surface boundary. As such, no severe weather probabilities will
be included in this forecast, despite a favorable overlap of
moderate to strong instability and sufficient vertical shear.
..Mead.. 09/01/2026
SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 PM CDT Tue Sep 01 2026
Valid 031200Z - 041200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE UPPER
OHIO VALLEY TO MID-ATLANTIC COAST...
...SUMMARY...
At least widely scattered severe storms, accompanied by damaging
gusts and perhaps some large hail, appear likely across portions of
the Ohio Valley to the Mid-Atlantic coast on Thursday. More isolated
severe storms capable of large hail and damaging winds appear
possible over the North Dakota-Minnesota Red River Valley into the
upper Midwest Thursday afternoon into night.
...Synopsis...
Broader-scale troughing is forecast over the western CONUS with
low-amplitude ridging from the upper MS Valley and upper Great Lakes
into the Southeast. Between the ridge and an upper low over QC,
latest model guidance indicates the progression of a short-wave
trough and associated 40-50 kt jet streak from the lower Great Lakes
through the Mid-Atlantic and portions of New England. Other more
subtle disturbances are depicted within the periphery of the ridge
over the Great Lakes into the upper MS Valley.
At the surface, an area of low pressure is forecast over the Dakotas
on Thursday with an associated warm front slowly lifting north
through the upper MS Valley and upper Midwest. The boundary is
expected to stretch east through the Great Lakes into the
Mid-Atlantic with the specific location of the boundary dictated by
the extent of thunderstorm activity and associated convective
outflow Wednesday night into Thursday morning.
...Great Lakes and Ohio Valley to Mid-Atlantic Coast...
One or multiple thunderstorm complexes may be ongoing Thursday
morning from the Great Lakes through the Northeast, aided by forcing
for ascent attendant to the previously mentioned mid-level
disturbances. The presence of the early-day storms leads to
uncertainty in the extent of air mass overturning that occurs, and
where the strongest instability will develop by afternoon. As such,
the Marginal Risk probability envelope has been broadened slightly
over the Mid-Atlantic with the Slight Risk probabilities remaining
unchanged.
The overlap of 30-40+ kt of deep-layer shear with a moist and
potentially moderately to strongly unstable warm sector will
conditionally support supercell and bowing storm modes with an
attendant risk for damaging wind gusts and large hail from Thursday
afternoon into evening.
...North Dakota-Minnesota Red River Valley into the upper Midwest...
A plume of steep mid-level lapse rates/EML is forecast to overly a
moist boundary layer, yielding a moderately to strongly unstable air
mass by afternoon in the vicinity of the warm front. The instability
will coincide with up to 40-50 kt of deep-layer shear, conditionally
yielding a very favorable severe storm environment. However, capping
concerns and the timing of any weak disturbances cresting the ridge
axis limit predictability, with only an areal increase in the
Marginal Risk probabilities included in this forecast. A categorical
upgrade to a level 2/Slight Risk may become necessary in subsequent
forecasts.
..Mead.. 09/01/2026
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1143 AM CDT Tue Sep 01 2026
Valid 011700Z - 021200Z
...Northeastern California and northern Great Basin...
An upper trough and attendant increasing mid-level southwesterly
flow will encompass much of northern California and the Great Basin
today. Southwest winds of 10-20 mph along with RH of 10-15% are
still expected across northeastern CA into the northern Great Basin
this afternoon. Some expansion of existing Elevated highlights were
warranted farther into northern NV and adjacent southern ID, with
wind gusts from the south-southwest of around 30 mph already
observed across the Independence Mountains/Jarbidge Wilderness area
even under cloud cover. Similarly dry, southerly flow is likely in
the southern Great Basin but marginal fuels should limit overall
fire weather threat through the afternoon.
..Williams.. 09/01/2026
.PREV DISCUSSION... /ISSUED 0103 AM CDT Tue Sep 01 2026/
...Synopsis...
A mid-level low pressure system currently off the west CONUS coast
will move onshore tonight, bringing southwest to southerly flow over
a good portion of the western US states today. Despite the delayed
onset of stronger 40-50 kt mid-level winds until late
afternoon/evening, a surface trough across the interior Northwest,
coupled with modest southwest 15-20 knot boundary layer flow, will
support southwest surface winds of 10-20 mph across northeastern CA,
far northwestern NV, and south-central OR. Though high temperatures
will fall short of normal for this time of year across much of the
far western CONUS, afternoon RHs will fall to near 10-15% across
much of the drawn area coincident with the aforementioned winds,
supporting an Elevated fire weather risk this afternoon which will
persist into the evening hours, particularly over the far western
Great Basin.
...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 Tue Sep 01 2026
Valid 021200Z - 031200Z
...Portions of Northern Rockies and northern High Plains...
Increasing deep layer southwesterly flow will affect portions of the
Intermountain West into the northern High Plains as a robust
upper-level trough enters the northwestern CONUS. A zone of dry,
southwesterly flow ahead of cooler, cloudier conditions across the
Pacific Northwest, will manifest in elevated fire weather concerns
for much of northeastern WY, far southwestern SD and
southwestern/southern MT Wednesday. Sustained southwest winds of
around 15 mph and relative humidity of 15-20% will promote elevated
fire weather concerns late Wednesday morning into the afternoon.
Localized and brief critical fire weather conditions including
sustained winds of 20 mph and RH as low as 10% are possible in
favored downslope areas, but a widespread critical fire weather
threat is not expected.
...Southeastern Nevada and Southwestern Utah...
A corridor of stronger southwest winds are expected in southeastern
portions of the Great Basin as the upper-trough shifts deeper into
the Northwest. RH reductions to below 10% by peak afternoon heating
are likely amid southwest winds of 15-25 mph. However, recent
rainfall and its mitigating effects on fuels precludes introduction
of highlights at this time.
..Williams.. 09/01/2026
.PREV DISCUSSION... /ISSUED 0106 AM CDT Tue Sep 01 2026/
...Synopsis...
A corridor of dry southwest flow southeast of the broader
upper-level trough over the Northwest will present fire weather
concerns where receptive fuels exist across portions of central and
northeastern WY, central and southern MT, and the low elevations of
far southwestern SD on Day 2/Wednesday. A persistent deep layer of
southwest flow amid lee surface troughing over the central/northern
High Plains will support southwest surface winds of 15-20 mph
coincident with afternoon RHs as low as 10% within portions of the
drawn area. Light rainfall prior to the onset of dry and windy
conditions is not anticipated to significantly impact fuels
receptivity.
Strong southwest winds of 15-25 mph and low daytime RH will also
occur from southern NV into western UT on Day 3/Wednesday. However,
recent more substantial rainfall has muted fuel receptivity across
this area, precluding any drawn areas.
...Please see www.spc.noaa.gov/fire for graphic product...
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