612
FXUS63 KLBF 130600
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
100 AM CDT Tue Aug 13 2024

.KEY MESSAGES...

- Abundant moisture may cause thunderstorms capable of locally
  heavy rainfall tonight and again Tuesday.

- Isolated severe storms are possible Tuesday and Wednesday. The
  primary hazards are large hail and wind damage.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 347 PM CDT Mon Aug 12 2024

A fairly strong UA disturbance moving through ern WY this
afternoon is the basis for chance to likely POPS across wrn
Nebraska tonight. Satellite shows a second disturbance across
nrn UT this afternoon and the RAP model shows both disturbances
sweeping through wrn and scntl Nebraska tonight.

The forecast uses a full blend of models, some of which, like the
GFS, show a "wet foot" across wrn Nebraska while others, like the
NAM show little or no rainfall. The reason for this is a second area
of organized thunderstorms will likely form across the Palmer divide
where the dynamics are weaker but the focus is better. Some models
suggest only one area of significant rainfall will occur- across
Colo. It worth noting satellite shows an separate UA disturbance
across wrn Colo which will move east and intercept the ongoing
convection across ern Colo/KS late tonight.

The drier model solutions across Nebraska tonight are wetter across
KS and Colo. The forecast wagers the strong dynamics across WY, UT
and Colo will support significant rain chances across Nebraska
and Colo/KS.

Thunderstorm chances are in place again Tuesday evening and
overnight for dynamics lifting east-northeast through Colo and
Nebraska. Water vapor and the models indicate a TUTT or
tropical upper tropospheric trof across AZ plus a disturbance
off the coast of nrn CA moving east-northeast. The models will
phase these disturbances across Colo/WY Tuesday presenting very
favorable upper level support.

The main upper low is far north across MT and this should be strong
enough to drive a warm front through wrn/ncntl Nebraska after
sunrise Wednesday morning. For the system Tuesday, we have focus,
moisture and upper level support. Chance/likely POPs for this event
follow the dynamics favoring swrn and ncntl Nebraska.

For both events, the models are in good agreement ramping up PWAT to
1.50 inches or higher and BUFkit indicates significant warm
precipitation processes to around 11kft.

Severe weather risks are marginal both days and this is mainly
forced by strong 0-6km shear 25-40 kts. The 0-8km is much stronger,
40-60 kts and given the modest instability, MLCAPE 2000-3000j/kg,
isolated severe storms would be the most likely concern. Out of all
the forecast features now through Wednesday morning, severe weather
is the most uncertain. The reason for this is the lack of sfc focus
and low level warm air advection which is anchored well south across
KS, south of a sfc cold front.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 347 PM CDT Mon Aug 12 2024

The upper level ridge of subtropical high pressure centered over
north Texas will drift east into LA this week and then migrate
west and amplify across NM this weekend and beyond. Nebraska
will likely remain under the belt of strong westerlies, or
northwesterly winds surrounding the ridge. More important is
subtropical moisture appears to be rotating around the ridge,
moving through Nebraska on many days. This would support at
least an isolated thunderstorm chance and a scattered chance if
a disturbance was present.

Temperatures at h700mb will warm to around 15C Saturday and remain
there through Monday. The reason for this is the upper level ridge
will amplify north into the cntl Rockies but it`s worth noting
mixing heights may not reach 700mb, especially if a backdoor cold
front moves into Nebraska as shown by the models. The temperature
forecast is relatively modest featuring highs in the 80s to near 90
next weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1252 AM CDT Tue Aug 13 2024

Low stratus and patchy fog will again be problematic for area
terminals to start early Tuesday.

High level clouds continue to track into the area from ongoing
and developing convection to the south and west. Recent
observations have shown decreasing CIGs at area terminals. This
is likely to continue as weak convection approaches from the
west. Support for this convection is poor, so a weakening trend
is expected. This casts doubts on direct impacts at either
terminal so will omit mention at this time. Ceilings will
continue to drop with MVFR then IFR conditions likely at LBF.
Fog will also be possible, but visibility restrictions are not
anticipated to be as severe as Monday morning.

Beyond late morning, CIGs will improve but potential exists for
LBF to see MVFR or worse criteria all day. Additional MVFR and
even IFR CIGs are possible late in the period with a return to
IFR conditions not ruled out.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...CDC
LONG TERM...CDC
AVIATION...NMJ