SPC Severe Thunderstorm Watch 283

WW 283 SEVERE TSTM AR OK 180250Z - 180900Z
      

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 283
NWS Storm Prediction Center Norman OK
950 PM CDT Sat May 17 2025

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Far Western Arkansas
  Central and Eastern Oklahoma

* Effective this Saturday night and Sunday morning from 950 PM
  until 400 AM CDT.

* Primary threats include...
  Scattered large hail and isolated very large hail events to 2
    inches in diameter possible
  Scattered damaging wind gusts to 70 mph possible
  A tornado or two possible

SUMMARY...Mainly elevated thunderstorms should continue to pose a
threat for large hail this evening into the early overnight hours.
The largest hailstones may reach up to 1-2 inches in diameter. There
is also some chance for a cluster of thunderstorms to form over the
next few hours. If this occurs, then the threat for severe/damaging
winds would increase as well.

The severe thunderstorm watch area is approximately along and 50
statute miles north and south of a line from 55 miles northwest of
Chickasha OK to 5 miles east southeast of Fort Smith AR. 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 279...WW 280...WW
281...WW 282...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
28035.

...Gleason


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SPC Severe Thunderstorm Watch 283 Status Reports

WW 0283 Status Updates
      

STATUS REPORT ON WW 283

THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.

..BROYLES..05/18/25

ATTN...WFO...TSA...OUN...


STATUS REPORT FOR WS 283 

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS 

ARC033-131-143-180540-

AR 
.    ARKANSAS COUNTIES INCLUDED ARE

CRAWFORD             SEBASTIAN           WASHINGTON          


OKC001-011-015-017-021-027-037-047-051-061-063-073-077-079-081-
083-087-091-093-101-103-107-109-111-117-119-121-125-127-133-135-
143-145-180540-

OK 
.    OKLAHOMA COUNTIES INCLUDED ARE

ADAIR                BLAINE              CADDO               
CANADIAN             CHEROKEE            CLEVELAND           
CREEK                GARFIELD            GRADY               
HASKELL              HUGHES              KINGFISHER          
LATIMER              LE FLORE            LINCOLN             
LOGAN                MCCLAIN             MCINTOSH            
MAJOR                MUSKOGEE            NOBLE               
OKFUSKEE             OKLAHOMA            OKMULGEE            
PAWNEE               PAYNE               PITTSBURG           
POTTAWATOMIE         PUSHMATAHA          SEMINOLE            
SEQUOYAH             TULSA               WAGONER             

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SPC Severe Thunderstorm Watch 282 Status Reports

WW 0282 Status Updates
      

STATUS REPORT ON WW 282

SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 SSW LLQ TO
35 NNE TXK TO 35 NNE DEQ.

..BROYLES..05/18/25

ATTN...WFO...LZK...SHV...


STATUS REPORT FOR WS 282 

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS 

ARC019-025-039-051-053-059-097-109-127-180540-

AR 
.    ARKANSAS COUNTIES INCLUDED ARE

CLARK                CLEVELAND           DALLAS              
GARLAND              GRANT               HOT SPRING          
MONTGOMERY           PIKE                SCOTT               


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.


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SPC - No MDs are in effect as of Sun May 18 09:15:06 UTC 2025

No Mesoscale Discussions are in effect as of Sun May 18 09:15:06 UTC 2025.

SPC May 18, 2025 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook
      
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1240 AM CDT Sun May 18 2025

Valid 181200Z - 191200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS
OF KANSAS AND OKLAHOMA...

...SUMMARY...
Severe thunderstorms capable of all severe hazards are expected
later today across portions of the central and southern Plains. The
potential for a few strong tornadoes exists across parts of Kansas
and Oklahoma.

...Central/Southern Plains...

Strong upper trough is digging southeast across the Great Basin
early this morning. This feature is forecast to advance into the
Four Corners region by 18z as 500mb speed max translates across AZ
into NM. By early evening, strongest mid-level flow is forecast to
extend across northeast NM into western KS. This evolution will
suppress the height field across the central High Plains such that
large-scale forcing will likely influence the dry line as far south
as I-40 near the TX/OK border.

While several 00z models struggle to develop convection along the
dry line, strong boundary-layer heating is expected across the
southern High Plains. Zero-3km lapse rates will approach dry
adiabatic by late afternoon as surface temperatures soar through the
mid 90s across the eastern TX Panhandle into the TX South Plains. As
a result, deep thermals are expected and isolated thunderstorms
should develop as CINH will prove minimal. 

Scattered convection is currently noted across northeast OK into
southeast KS/southwest MO. This activity will likely persist into
the early parts of the day1 period. Strongest low-level moisture
surge should be across western OK into extreme southwest KS as LLJ
will focus across this portion of the Plains early in the period.
While early-day convection may generate locally severe hail/wind,
the primary concern for severe will be with late-day convection.
Current thinking is strong heating along the dry line will prove
instrumental in thunderstorm development as convective temperatures
are breached, sometime after 22z. Primary corridor for initiation
should be across southwest KS into northwest OK. This activity will
be strongly sheared and supercells should mature quickly as they
move northeast toward/across the warm front draped downstream across
KS. Very large hail and tornadoes are certainly a concern with
surface-based convection, while hail is the primary concern with
elevated convection north of the warm front.

It's not entirely clear how much convection will develop along the
dry line south of I40, especially across TX. However, minimal
inhibition warrants concern, as any updrafts that evolve within a
strongly sheared and buoyant air mass should produce at least large
hail.

Farther north, left-exit region of mid-level jet will encourage a
secondary corridor of strong/severe thunderstorms from northeast CO
into western NE. Surface low is expected to track across eastern CO
into western KS which will maintain a moist/upslope component to
boundary layer across this portion of the High Plains. Strong
low-level warm advection will assist organized convection as it
spreads northeast during the overnight hours.

..Darrow/Halbert.. 05/18/2025


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SPC May 18, 2025 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook
      
Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
0100 AM CDT Sun May 18 2025

Valid 191200Z - 201200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE CENTRAL/SOUTHERN PLAINS INTO THE OZARKS....

...SUMMARY...
Severe storms with all severe weather hazards are expected from the
central/southern Plains into the Ozarks on Monday.

...Synopsis...
A mid-level trough will shift from the Intermountain West into the
central Plains on Monday. A moderate to strong mid-level jet streak
will emerge along the southern periphery of this trough from the
Southwest into the central/southern Plains. A surface low in
Nebraska will gradually consolidate southward and deepen as the
mid-level jet emerges across the southern Plains. A sharp dryline
will be present from central Kansas to central Oklahoma and
north-central Texas. A warm front will extend from near Omaha to the
lower Ohio Valley and remain mostly stationary during the day. 

...Central/Southern Plains into the Ozarks...
Thunderstorms will likely be ongoing along the warm front in the
northern Missouri border vicinity on Monday morning. Otherwise, a
mostly convection-free warm sector is expected to the south. Very
strong instability will develop along and east of the dryline with
convective temperatures likely reached by early afternoon. As large
scale ascent ahead of the approaching trough overspreads the
dryline, expect scattered supercells to develop along the dryline in
Kansas and Oklahoma. Very large to potentially giant hail will be
possible with these supercells initially. In addition, hodographs
will support tornadoes. The tornado threat will increase through the
afternoon and peak during the evening as the low-level jet
strengthens and low-level shear increases. However, by this time,
storm mode could be messy which is one factor precluding higher
probabilities at this time. 

00Z CAM guidance shows a range of solutions including:

1. Earlier storms as the primary threat.

2. Delayed dryline initiation with a potential tornado outbreak type
solution across central/eastern Kansas and central/eastern Oklahoma.

3. A combination of both solutions. 

The uncertainty in guidance at this time precludes a moderate risk,
but higher probabilities may be needed when a more favored solution
becomes more clear, especially if one of the higher-end scenarios
appears likely.

..Bentley.. 05/18/2025


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SPC May 18, 2025 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook
      
Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
0230 AM CDT Sun May 18 2025

Valid 201200Z - 211200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF
THE MID-MISSISSIPPI VALLEY...OHIO VALLEY...AND TENNESSEE VALLEY...

...SUMMARY...
Severe thunderstorms are likely across portions of the Ohio Valley,
Mid-Mississippi Valley, and Tennessee Valley on Monday.

...Synopsis...
A mid-level low will stall and perhaps start to retrograde across
parts of the Upper Midwest on Monday. A surface low in the MO/IL
region will start to occlude during the day. A cold front will move
east through the period with a warm front across the Ohio Valley.

...Mid-Mississippi Valley into the Ohio Valley and Tennessee
Valley...
Thunderstorms will likely be ongoing amid broad isentropic ascent
and moderate elevated instability along the warm front in southern
Illinois and Indiana and vicinity on Monday morning. South of this
morning activity, where upper 60s to low 70s dewpoints are
anticipated, moderate to strong instability is forecast to develop
amid daytime heating. As 55 to 65 knots of mid-level flow
overspreads the warm sector, strong shear will be present for
supercells. Large to very large hail will be the primary threat
initially, as low-level flow will likely be veered. However,
low-level shear should be strong enough to support some tornado
threat during the afternoon/evening. As storms grow upscale, one or
more bowing segments may develop with an increased damaging wind
threat during the evening and perhaps persisting into the overnight
period.

..Bentley.. 05/18/2025


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SPC May 18, 2025 Day 4-8 Severe Weather Outlook

Day 4-8 Outlook
      
Day 4-8 Convective Outlook  
NWS Storm Prediction Center Norman OK
0345 AM CDT Sun May 18 2025

Valid 211200Z - 261200Z

...DISCUSSION...
A few strong to isolated severe storms are possible in the eastern
Carolinas on Wednesday as a mid-level trough shifts east across the
eastern CONUS. It is unclear whether there will be substantial time
for destabilization before the surface low/front moves into the
Atlantic Ocean. Therefore, no probabilities are necessary for
Wednesday/D4 at this time.

Once this front moves offshore, a more benign period of severe
storms appears likely. The cold front will move south near the Gulf
Coast and into Florida with mostly sub 60s dewpoints across the
Eastern CONUS in its wake. Farther west the front is expected to
stall across Texas with low-level flow expected to advect moisture
westward to the High Plains on Thursday/D5.

Sufficient moisture should be in place by D7/Saturday across the
Plains. Therefore, some greater severe weather potential will likely
return by next weekend. However, uncertainty currently remains high
regarding the amplitude of the mid-level ridging and the location of
surface boundaries. Therefore, no probabilities have been introduced
at this time.


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SPC Day 1 Fire Weather Outlook

SPC Day 1 Fire Weather Outlook
          
Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0110 AM CDT Sun May 18 2025

Valid 181200Z - 191200Z

...CRITICAL FIRE WEATHER AREA FOR SOUTHERN NEW MEXICO...

...Synopsis...
As a mid-level shortwave trough progresses from the Four Corners to
the southern High Plains, and a surface lee cyclone deepens
throughout the morning and afternoon, Critical fire-weather
conditions are anticipated across much of southern New Mexico.
Further west, mid-level northerly flow on the western side of the
trough is expected to bring Elevated fire-weather conditions to the
Sacramento and San Joaquin Valleys.

...Southern New Mexico...
Deep boundary-layer mixing behind a sharpening dryline, along with a
deepening surface cyclone and associated gradient wind response,
will be responsible for widespread Critical fire-weather conditions
this afternoon. Sustained winds of 25 MPH and relative humidity
below 10%, along with highly receptive fuels, will result in
conditions that support rapid wildfire ignition and spread. Some
downslope winds in southern and eastern New Mexico may even locally
reach Extremely Critical criteria, with sustained winds exceeding 30
MPH. However, such conditions appear to be too localized for larger
highlights at this time. Additionally, the Critical meteorological
conditions will exist well into the Texas Panhandle and portions of
southern Kansas -- but ERC fuels guidance shows fuels are not quite
as receptive, warranting only Elevated highlights. 

...Sacramento and San Joaquin Valleys...
Deep boundary-layer mixing beneath modest mid-level northerly flow
will result in dry and windy conditions across much of the interior
California valleys. Winds of 15 MPH and relative humidity at or
below 15% are expected. Fuels appear more marginal, but there is
some signal for fuel receptiveness, warranting at least Elevated
highlights.

..Halbert.. 05/18/2025

...Please see www.spc.noaa.gov/fire for graphic product...


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SPC Day 2 Fire Weather Outlook

SPC Day 2 Fire Weather Outlook
          
Day 2 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0112 AM CDT Sun May 18 2025

Valid 191200Z - 201200Z

...CRITICAL FIRE WEATHER AREA FOR SOUTHERN NEW MEXICO INTO FAR
WESTERN TEXAS...

...Synopsis...
As a mid-level trough moves out of the Great Basin and into the
southern Great Plains on Monday, dry down-slope winds behind a
dryline in southern New Mexico into far western Texas will result in
Critical fire-weather conditions. Additionally, some persistent
northerly flow over central California will result in Elevated
fire-weather conditions across portions of the San Joaquin valley. 

...Southern New Mexico into Far Western Texas...
Westerly down-slope winds in New Mexico beneath a progressive
mid-level trough, along with deep boundary-layer mixing and a
deepening surface cyclone, will result in widespread Critical
fire-weather conditions across southern New Mexico Monday afternoon.
Winds in excess of 25 MPH with relative humidity at or below 10%
will overspread a region of fuels that are at or above the 90th
annual ERC percentiles, and will result in conditions that support
rapid wildfire ignition and spread. Some locally Extremely Critical
conditions may occur, with winds in excess of 30 MPH, across
portions of southern New Mexico. However, they appear too localized
for highlights at this time. 

...Central California...
Ensemble guidance suggests that deep boundary-layer mixing beneath
persistent mid-level northerly flow will result in Elevated
fire-weather conditions. While fuels are on the more marginal side,
15+ MPH winds and relative humidity at or below 15% will support at
least Elevated highlights.

..Halbert.. 05/18/2025

...Please see www.spc.noaa.gov/fire for graphic product...


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