SPC Severe Thunderstorm Watch 248

WW 248 SEVERE TSTM CO NE 292015Z - 300300Z
      

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 248
NWS Storm Prediction Center Norman OK
315 PM CDT Mon May 29 2023

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Northeast Colorado
  Western and Central Nebraska

* Effective this Monday afternoon and evening from 315 PM until
  1000 PM 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

SUMMARY...Scattered thunderstorms will continue to intensify across
western Nebraska and spread across the watch area.  The strongest
cells will pose a risk of large hail and damaging wind gusts.

The severe thunderstorm watch area is approximately along and 70
statute miles east and west of a line from 30 miles northeast of
Ainsworth NE to 35 miles west of Imperial NE. 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
2 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
27025.

...Hart


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SPC Severe Thunderstorm Watch 248 Status Reports

WW 0248 Status Updates
      

STATUS REPORT ON WW 248

THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA.

..SPC..05/29/23

ATTN...WFO...BOU...LBF...CYS...


STATUS REPORT FOR WS 248 

SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS 

COC075-095-115-300040-

CO 
.    COLORADO COUNTIES INCLUDED ARE

LOGAN                PHILLIPS            SEDGWICK            


NEC005-009-015-017-029-031-033-041-049-063-069-071-075-085-089-
091-101-103-105-111-113-115-117-135-149-171-183-300040-

NE 
.    NEBRASKA COUNTIES INCLUDED ARE

ARTHUR               BLAINE              BOYD                
BROWN                CHASE               CHERRY              
CHEYENNE             CUSTER              DEUEL               
FRONTIER             GARDEN              GARFIELD            
GRANT                HAYES               HOLT                
HOOKER               KEITH               KEYA PAHA           
KIMBALL              LINCOLN             LOGAN               
LOUP                 MCPHERSON           PERKINS             
ROCK                 THOMAS              WHEELER             


THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY.  PLEASE

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SPC MD 896

MD 0896 CONCERNING SEVERE THUNDERSTORM WATCH 248... FOR CENTRAL PLAINS
        

Mesoscale Discussion 0896
NWS Storm Prediction Center Norman OK
0600 PM CDT Mon May 29 2023

Areas affected...Central Plains

Concerning...Severe Thunderstorm Watch 248...

Valid 292300Z - 300100Z

The severe weather threat for Severe Thunderstorm Watch 248
continues.

SUMMARY...Isolated severe thunderstorms will persist across ww248
this evening. Hail continues to be the main threat.

DISCUSSION...Weak mid-level short-wave trough is currently evident
in water-vapor imagery extending from eastern MT into extreme
northwest NE. This feature will advance east this evening with the
southern extent expected to influence convection that has developed
across portions of central/northern NE. Latest diagnostic data
suggests 25-30kt 500mb flow will overspread the northern half of
ww248 where modest instability (2000 J/kg MLCAPE) currently resides
ahead of a lee surface trough from near OGA to near ANW. Isolated
robust convection has evolved along this corridor and several
updrafts appear to have hail on the order of 1 inch at times. Hail
remains the primary risk, though gusty winds are also possible. This
activity will shift slowly east this evening as weak LLJ shifts into
northeast NE-southwest MN after sunset.

..Darrow.. 05/29/2023

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

ATTN...WFO...FSD...OAX...LBF...BOU...CYS...

LAT...LON   40500361 42870093 42879818 40510093 40500361 


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SPC May 29, 2023 2000 UTC Day 1 Convective Outlook

SPC 2000Z Day 1 Outlook
      
Day 1 Convective Outlook RESENT 1
NWS Storm Prediction Center Norman OK
0413 PM CDT Mon May 29 2023

Valid 292000Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
THE NEBRASKA VICINITY...

...SUMMARY...
Isolated strong to severe thunderstorms capable of producing hail
and damaging winds remain possible this afternoon and evening in
parts of the central High Plains into Nebraska and South Dakota.

...Discussion...
With current expectations in line with the ongoing outlook, no
appreciable changes appear necessary with this update.  For
additional short-term information, please refer to MCD 893 and 894.

..Goss.. 05/29/2023

.PREV DISCUSSION... /ISSUED 1117 AM CDT Mon May 29 2023/

...Northern and Central Plains...
A weak upper trough remains in place over the northern and central
Plains states today, providing relatively cool temperatures aloft
and subtle large-scale forcing for ascent across the region.  This
will lead to scattered afternoon thunderstorm development, and at
least some potential for hail and gusty winds.  Forecast soundings
throughout the region show moderately steep mid level lapse rates
and just enough bulk shear for marginal organization.  Therefore
will maintain the MRGL risk for much of the region.

One area that appears to have a slightly more favorable environment
is along a weak surface confluence zone that extends from southwest
to northeast NE.  A consensus of CAM solutions suggest this narrow
corridor will become convectively active by late afternoon. A 30-40
knot westerly mid-level jet will track across WY and nose into this
region this evening, enhancing the deep-layer shear and further
promoting a few severe storms, with a risk of large hail and
damaging winds for a few hours.

...South TX...
A weak upper trough is also tracking across TX today, where a very
moist and moderately unstable air mass will develop this afternoon
(MLCAPE around 2000 J/kg). Winds aloft are sufficiently strong to
aid in organization to any robust thunderstorms that can form. 
Given the 12z CAM solutions of widely scattered convection, will add
a MRGL risk area for afternoon/evening hail and wind risk.


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