867
FXUS63 KGID 051120
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
620 AM CDT Sun May 5 2024

.KEY MESSAGES...

- Enhanced risk for severe thunderstorms Monday
  afternoon/evening. All forms of severe weather will be
  possible, including tornadoes. Thunderstorms may initially
  develop as supercells across our western zones and then become
  more linear and more widespread as they track east across our
  eastern zones.

- Temperatures will be pretty steady over the 7 day forecast
  period, with highs expected to be in the 60s and 70s.

- While conditions will be mostly dry Tuesday through early next
  weekend, there will be a few chances for showers and
  thunderstorms, primarily Tuesday evening and Tuesday night.

&&

.DISCUSSION...
Issued at 303 AM CDT Sun May 5 2024

Today...

Surface high pressure departing to the east and an upper level
ridge overhead will keep conditions dry today. Temperatures will
be seasonably warm with highs in the mid- to upper 60s across
the area. As the area of high pressure moves east this
afternoon, the pressure gradient will tighten ahead of our next
weather system and SSE winds will increase, with gusts of 20 to
30 mph expected. As the front gets closer tonight and into
Monday morning, these winds will increase further and gusts
increasing to 25-35 mph after midnight (windiest west of Highway
281).

Monday...

This is the next chance for severe weather across the area.
There is a chance (30-40%) of a few showers or thunderstorms
Sunday night into Monday morning but if those do occur, that
will not be the main event. With the entire area covered by a
Slight Risk (2 out of 5) and much of the area in an Enhanced
Risk (3 out of 5) for severe weather Monday afternoon and
evening, it will be very important to have multiple ways to
receive weather warnings. All forms of severe weather will be
possible, including strong straight-line winds, large hail, and
tornadoes. Latest model guidance indicates that thunderstorms
will begin to develop early in the afternoon over the western
portions of the forecast area or just to the west of the
forecast area early Monday afternoon (most likely around 2PM BUT
could be as early as noon). These will be firing up just east
of a dryline feature set up over the area, most likely initially
as supercells. As a cold front moves over the area this system
is expected to evolve into a linear system at some point (hard
to determine exactly how quickly that transition occurs). Some
models have this occurring late afternoon but some have this
occurring very quickly after storm initiation. CAPE values are
expected to be in the 1500-2500 J/kg range over our forecast
area with ample deep layer shear and good storm-relative
helicity from the surface all the way up to 6km vertically,
which reinforces the potential for tornadoes and very large
hail, with an increasing wind threat as this develops into a
line of storms Monday afternoon. For the tri-cites area, model
guidance continues to indicate that these storms will move
through between 2 and 5 PM. The severe weather threat will
increase as we get later into the day, favoring the tri-cities
as well as areas east and southeast of the tri-cities with the
worse of the severe weather.

This is a good pattern for a Plains severe weather outbreak, but
favoring Kansas and Oklahoma with the worse of it rather than
Nebraska. The main limiting factor will be how much sun we see
after the potential for those early morning showers/storms (too
little sun will inhibit any increase in instability and delay
storm initiation), so there is still that uncertainty with this
potential severe weather outbreak.

Tuesday through Saturday...

This will be an overall drier period with most areas seeing
little precipitation. We do have some small POPs in the
forecast, mainly Tuesday night/Wed morning and again Thursday
evening, but have pretty low confidence in either of these
occurring and precipitation should be isolated if it does occur.
Temperatures will be seasonable with highs in the 60s and 70s.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 613 AM CDT Sun May 5 2024

VFR conditions and clear skies are expected throughout the day
Sunday, with SSE winds at 6-8 kts increasing to 10-15 kts
shortly after sunrise and up to 15 kts sustained with gusts to
20-25 kts Sunday afternoon as low pressure deepens on the lee
side of the Rockies. Sunday evening, cloud cover is expected to
increase with BKN skies around 8k ft AGL. Sunday night, expect
sustained SE winds of 15-20 kts and gusts of 25-30 kts, and
these gusty winds will persist through the end of the TAF
period. Ceilings will become MVFR by late Sunday evening, and
IFR with CIGs < 1000 ft AGL starting shortly after midnight and
persisting through the end of the TAF period Monday morning.

&&

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

&&

$$

DISCUSSION...Hickford
AVIATION...Hickford