815
FXUS63 KLBF 300510
AFDLBF

Area Forecast Discussion
National Weather Service North Platte NE
1210 AM CDT Thu May 30 2024

.KEY MESSAGES...

- Severe storms are possible this evening, mainly along and west
  of highway 61

- Severe storms are possible Thursday afternoon, mainly along
  and east of highway 83.

- Large hail and wind damage are the main concern both days.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 333 PM CDT Wed May 29 2024

The CAMs, including the HREF are firing a few areas, or clusters, of
storms off the Laramie Range and Pine Ridge around 18z this
afternoon. The models generally show modest upscale growth and move
the storms in an easterly direction arriving in wrn Nebraska around
23z-00z this evening. A general east southeast motion is expected
tonight and weakening is expected by 04z. The storms should continue
to drift east through ncntl Nebraska late tonight, carried along by
the nocturnal the low level jet.

Some of the salient severe weather features are modest winds aloft,
15-30kts at h500-300mb, 20-30kt southerly winds at h850-700mb for
effective shear 30-40kts. Strong 850-700mb moisture and theta-e
advection is shown by the RAP model this evening. The CAMs wind gust
products suggest strong moisture advection and modest shear aloft
will cause the storm complexes to form cold pools. Fairly strong WAA
will be directed through the WY and Colo ranges and this often
produces the severe weather near those ranges. As the storms move
away into wrn Nebraska, they weaken. This is the basis for the SPC
Day1 outlook of a relatively narrow north-south stripe of severe
weather potential along the high Plains.

Heating today will cause the warm lapse rates this morning to become
steep by late afternoon. The associated MLCAPE, 1000-1500J/KG,
supports a large hail threat while damaging winds appear to be the
primary severe weather hazard. It is worth noting, the non-CAM RAP
model shows just isolated storm coverage; the strength of the CAMs
are their ability to predict upscale growth.

The models show a weak frontal boundary draped across Nebraska
oriented across southwest to northeast Thursday afternoon and this
will be the focus for additional storm development mid-afternoon
onward, generally along and east of highway 83. For this event, the
RAP model suggests scattered storms while the CAMS suggest slightly
less storm coverage. The HREF indicates isolated coverage.

Winds aloft Thursday are problematic; the westerlies at h500mb back
and become south at h300mb. This is not the favored profile for
severe storms. Lapse rates, associated MLCAPE and moisture
availability are still strong during the daytime. SPC gives just a
marginal severe weather risk for this set up.

The POP forecast tonight leans on the CAMs and HREF and the RAP
model Thursday for likely POPs along and west of highway tonight;
mostly east of highway 83 Thursday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 333 PM CDT Wed May 29 2024

Sunday and Tuesday are the best chances for thunderstorms in the
extended forecast.

This storm activity will be guarded by nrn stream disturbances
emanating from an upper level low parked across the Gulf of Alaska.
Jet winds of 30-40kts at h500-300mb Sunday suggest the potential for
severe storms. These winds increase to 40-50kts Tuesday. Isolated
storm chances are in place during much of the rest of the extended
forecast. The NAM, SREF, GFS and ECM all show isolated storms
forming Saturday afternoon, for example.

The 850-700mb theta-e advection and moisture transport in both the
GFS and ECM support strong storms. The best minds at SPC will make
the call on the level of severe weather most likely to develop in
later forecasts. For severe weather is possible Saturday through
Tuesday.

Thereafter, the models are in good agreement amplifying heights
across the Rockies. The ongoing heat wave across Mexico will build
north into the wrn U.S.. Wrn/ncntl Nebraska will not be in the heart
of the heat, but near the ern edge of the ridge. This type of
northwest flow appears to be favoring storm development off the Colo
Rockies which will dive south through KS and the srn Plains. The
forecast is dry next Wednesday.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1201 AM CDT Thu May 30 2024

Scattered -TSRA across southwest and north central Nebraska
will continue to move east overnight with no impacts to KLBF and
KVTN.

Otherwise, VFR conditions are expected at both KLBF and KVTN
until at least 12Z. Thereafter, ceilings will lower with MVFR
conditions expected at both sites through the early afternoon
with a return to low-end VFR conditions for remainder of the
period. Southerly winds will veer towards the north/northeast by
this afternoon.

&&

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

&&

$$

SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Viken