733
FXUS63 KGID 231136
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
636 AM CDT Thu May 23 2024

.KEY MESSAGES...

- "ENHANCED RISK" for severe weather this evening into tonight
  for most of the area. Primary threat will be severe winds to
  75 mph, but large hail to the size of golf balls and a few
  tornadoes are also possible. Greatest severe threat (10PM-3AM)

- Cooler (67-74F) and dry behind the cold front on Friday.

- Next upper level storm system will bring another chance for
  severe storms Saturday afternoon into Saturday night with a
  SPC Day 3 "SLIGHT" risk area.

- Rain chances will continue into Sunday (30-50%), but then
  decrease for Monday (10-20%). Good confidence in cooler highs
  in the upper 60s to around 70 on Sunday and then mainly 70s
  for memorial day.

&&

.DISCUSSION...
Issued at 339 AM CDT Thu May 23 2024

Today/Tonight (Severe Thunderstorms)...
We have some early morning showers with perhaps just a few
lightning strikes tracking east near and south of the Kansas
border early this morning. This area of showers should quickly
diminish with remnants sliding east of our area by 6-8 AM. The
rest of the morning and at least early afternoon should then be
dry.

Most areas including the Tri-Cities should be dry today through
at least 8 PM. We will see a slight chance (20%) for isolated
thunderstorm development within the warm sector out ahead of the
cold front. The most likely location for any earlier
development in the 4-8 PM window will be across our far western
zones. We do have a few models like the 00Z and 06Z NAM NEST
that try to develop these isolated supercells during day time
hours out ahead of the cold front. However, a strong cap over
the warm sector will make it difficult for thunderstorms to
develop except for right along the cold front. Other models
like the 06Z NAM and 06Z HRRR keep thunderstorms out of our area
until a line of storms track from west to east across the
forecast area with the front tonight between 10 AM and 3 PM.

Strong to severe thunderstorms are likely (70-90%) across the
area tonight as that cold front swings through with the highest
likelihood across our Nebraska counties. How far south into
Kansas and how quickly thunderstorms develop along the front
remains a bit in question. A QLCS with bowing line segments is
the main forecast concern tonight as thunderstorms along the
cold front are fed by a strong moist 50 kt 850 mb low level
jet, which with high confidence (70-90%) will keep that line of
storms going through much of the night right through our CWA.
The primary severe weather threat during the late night hours
with this QLCS will be severe winds including the potential for
a few high end severe wind reports of over 75 mph. The larger
golf ball hail threat will primarily be with any isolated storms
that can form earlier or during the earlier portion of the
lines development.

There will be a tornado threat with any discreet supercells
that can develop out ahead of the line, but again this is a
small probability of seeing discreet supercells (20%). There
will also be a chance for rain wrapped QLCS tornadoes embedded
within the bowing line segments late this evening as the low
level shear ramps up. The 06Z NAM indicates 40kts of 0-1km shear
ahead of the line tonight with 0-3 km helicity values to over
500 m2/s2


Friday (Cooler and Dry)...
Cooler (67-74F) and dry behind the cold front on Friday with
breezy northwest winds at 15-20 mph gusting 25-30 mph.


Saturday/Saturday Night (Next Chance For Severe
Thunderstorms)...

The best chance (40-60%) for thunderstorms will be ahead of a
quick moving upper trough late Saturday evening into Saturday
night. However, we could see thunderstorms develop as early as
late Saturday afternoon, mainly after 4 PM, but with lower
probability (20-30%) for these earlier thunderstorms. This
upper trough should be a quick mover and we don`t get much time
for return moisture to flow back into the region after the
moisture vacates the area on Friday behind the cold front.
Therefore, the better chance for strong to severe storms will be
south of our forecast area Saturday evening/night where there
will be better moisture/instability.


Sunday through Memorial Day...
We could see some lingering mainly showers on Sunday, but can`t
rule out a few thunderstorms. Our NBM rain chances are probably
a bit on the high side and may need to be lowered with future
forecast updates as the upper pattern becomes less favorable for
precipitation. The NBM low 20% rain chances on Memorial day may
also be a bit on the high side and most areas will likely see a
dry Memorial Day. However, temperatures will not be all that
warm with mainly 60s on Sunday and then lower to middle 70s for
Memorial Day.


Tuesday and Wednesday...
Mainly dry weather expected and warming back up into the upper
70s and lower 80s.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 632 AM CDT Thu May 23 2024

The primary aviation concern centers around figuring out the
timing on when the line of thunderstorms should track through
our TAF sites. For now will go with a 3 hours window this
evening, but might be able to narrow this down as we get closer.
These thunderstorms could also be severe with stronger wind
gusts than indicated in the TAF. There will also be strong wind
shear in and around thunderstorms as well, but overall the wind
shear will probably not meet criteria except for right in and
around thunderstorms. The gusty south winds will become
northwestern when the thunderstorms push into the area. This is
a high probability forecast of getting thunderstorms this
evening (70-90%).

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.

&&

$$

DISCUSSION...Wesely
AVIATION...Wesely