225
FXUS63 KGID 301043
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
543 AM CDT Sun Jun 30 2024

.KEY MESSAGES...

- Another seasonably cool day today with some areas of
  showers/weak storms.

- Much warmer and more humid for the start of the new work week.
  Areas along and south of the state line will likely experience
  heat indices into the low 100s Monday, and perhaps again on
  Tuesday depending on timing of a cold front.

- Elevated thunderstorms will bring potential for marginally
  severe hail late tonight into early Monday morning, but
  greater risk of more significant severe storms will come late
  Monday afternoon into the evening and overnight.

- Semi-active pattern will continue through much of the week
  thanks to series of fronts and weak disturbances. This could
  mean off and on thunderstorms on and around the 4th of July
  holiday. Daily highs will tend to favor near to just below
  normal levels in the 80s to low 90s.

&&

.DISCUSSION...
Issued at 520 AM CDT Sun Jun 30 2024

Much quieter conditions in place compared to 24 hours ago as
skies are mostly clear and temperatures are fairly cool in the
50s to low 60s. ODX may even touch the upper 40s prior to
sunrise. Great opportunity to open the windows and give the AC a
break! The dry/quiet weather will be short-lived, however, as
showers and weak storms associated with mid level warm air
advection over S KS are still forecast to lift N towards the
KS/NE state line by around midday. This activity is forecast to
weaken some with time and NEward extent this afternoon, but
would think at least sprinkles would be possible for most areas
through 4-6PM. Latest HRRR runs have trended more aggressive
with today`s rain chances, and thus have trended cooler on high
temps - particularly W of Hwy 281 where rain and thicker clouds
look to be most prevalent/widespread. Taken verbatim, areas
along Hwy 183 corridor could struggle to get into the low 70s,
so was most aggressive in trending highs cooler for these
areas. Rain amounts look to average around 0.10-0.30" from the
Tri- Cities S and W, with locally higher amounts towards
0.50-0.75" possible along/S of the state line in convective
elements. All in all, today has trended rainier for more of the
daytime hrs, esp along/S of I-80 and along/W of Hwy 281.

Expect a lull in rain chances this evening into the first half
of the overnight tonight, but a strengthening and veering low
level jet should bring fairly high chances (50-70%) back to
majority of south central NE and north central KS after midnight
through mid-AM Monday. This activity will have pockets of
greater instability (MUCAPE up to 1000-1500 J/kg) and effective
shear (30-40kt) to work with, so some marginally severe hail
can`t be ruled out in the strongest cores. Most model guidance
has majority of rain E of the forecast area by noon Mon. Rain
amounts with this round look to be similar to slightly higher
than today`s round, though the high end of the localized
amounts could be higher in the 1-1.5" range.

Once the AM rain exits, focus will quickly turn to much warmer
and more humid conditions for the afternoon. Because of the AM
rain, highs are somewhat uncertain for areas N and E of the Tri-
Cities, but S and W will likely become quite hot as air temps
peak in the mid 90s to lower 100s. Models suggest some
greater/deeper mixing and lower dew points for these areas, but
even mid-upper 60s Tds would still support heat indices several
deg higher than the air temps - generally 100-107F, highest in
our KS counties. Brzy SE winds will provide at least SOME
relief, fortunately. After coordination with neighboring offices
the consensus was to hold off on any heat headlines at this
time, but wouldn`t be shocked if next shift issued a Heat Advsry
for at least our KS counties, esp. Beloit area, as relief Mon
night could be limited with lows only in mid-upper 70s.

Sfc low pressure is forecast to deepen near the CO/NE/KS border
area by late Mon aftn in response to right entrance region of
seasonably strong mid level jet streak ejecting from the central
Rockies into N Neb. A warm front will arc E/SE from the low,
separating a very hot/deeply mixed airmass and very steep low
level lapse rates to the S from much more moist and unstable
airmass to the N thanks to pooling Tds in the low to mid 70s.
Some sort of inverted trough-like feature may extend to the N
into the Neb. Sandhills region. Capping will likely be a
significant hindrance to convection through most, if not all, of
the afternoon thanks to H7 temps around 13-14C. However, subtle
height falls associated with weak disturbance in WSW upper flow,
along with sustained convergence near the triple point and
associated boundaries could be enough to erode the cap
sufficiently for vigorous tstm development around 23-00Z. IF the
cap breaks, storm development could be fairly explosive given
strong instability (MLCAPE 2500-3500+ J/kg) and higher end deep
layer shear by early July standards (35-50kt), thanks to
aforementioned mid level jet streak. Even low level shear will
be enhanced by strengthening low level jet Mon eve, supporting
0-3km SRH values of 150-250 m2/s2. Thus, all severe hazards will
be possible, including a few tornadoes and very large hail.
Locally intense wind gusts over 70 MPH will also be possible,
particularly with any upscale growth Mon eve. Much of south
central Nebraska (most likely area to be along/N of warm front)
remains in a Slight Risk (level 2 of 5) on latest SPC outlook,
with the main limiting factor to an upgrade being questions on
capping and overall storm coverage. Could certainly envision an
increase to "Enhanced" (level 3 of 5) once mesoscale details
become more clear following Mon AM convection.

The cold front will likely still be bisecting at least parts of
the area, most likely SE of the Tri-Cities, on Tuesday, with
areas behind the front cooler in the 80s, but continued hot and
humid to the SE for areas like Beloit to Hebron. Another round
of strong to severe storms will be possible along and SE of the
front by late Tue aftn/eve within environment of moderate
instability and continued seasonably strong shear. Shear vectors
largely parallel to the cold front and linear forcing suggest
mainly hail to high wind threat evolution. Locally heavy rain
also possible given short-term training and PWATs 1.6-1.9", or
roughly +2 standard deviations above normal.

Would think at least a semi-active pattern will continue through
the end of the week thanks to zonal upper flow and possibility
for Tuesday`s front to stall out near/just S of the area and
perhaps even lift back northward sometime Wed into Independence
Day. Just too far out to work out specific details regarding
timing and placement, however. Of higher confidence is that with
the flatter mid/upper flow should be temperatures closer to, or
even a bit below, normal...so mainly 80s with perhaps some lower
90s in KS. Certainly can`t rule out some "natural fireworks" for
Independence Day celebrations, so those with outdoor interests
will need to keep an eye on the latest forecasts. Ensemble
precip probabilities tend to drop off some towards next weekend.


&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1250 AM CDT Sun Jun 30 2024

For KGRI/KEAR Airports:

VFR conditions should prevail for most of the valid period,
though expect increasing mid to high level clouds throughout the
daytime hours today. Could see enough of an incr in low level
moisture such that MVFR CIGs move in sometime this evening.
Maintained an aftn VCSH at EAR, but appears the vast majority of
this high-based showery activity should remain off to the S. NE
winds currently will veer to SErly for the daytime hrs, becoming
a bit brzy for the afternoon. Confidence: High.

&&

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

&&

$$

DISCUSSION...Thies
AVIATION...Thies