Drought in Nebraska, July 1 to 31, 2023

Area Forecast Discussion
National Weather Service North Platte NE
634 PM CDT Fri Jun 30 2023

...UPDATED AVIATION FORECAST DISCUSSION...

.SYNOPSIS...
Issued at 237 PM CDT Fri Jun 30 2023

Key Messages:

- Multiple rounds of showers and thunderstorms are expected this
  evening through late Saturday afternoon. Heavy rainfall is the
  main threat, however, strong to briefly severe thunderstorms
  cannot be ruled out for areas across far southwest Nebraska.

- Dry and warming conditions return for a brief period on Sunday
  and Monday ahead of another potentially wet and active period
  beginning late Monday through the latter end of the week.

Recent GOES-16 WV and RAP 500-mb analysis showed a positively tilted
trough extending from Wyoming into Arizona, moving eastward from the
central Rockies and approaching the Nebraska Panhandle. Further
northeast of this feature, an upper-level trough of low pressure was
centered across Ontario, extending across the Upper Midwest and
Great Lakes region. Broad upper-level high pressure was anchored
across the Gulf Coast area. All of these features combined has
resulted in southwesterly flow aloft across western and north
central Nebraska. At the surface, an area of low pressure was noted
across eastern Kansas with a stationary front draped southwest
across Kansas to another surface low centered across the Oklahoma
Panhandle. As of 2PM CT, temperatures ranged from 72 degrees at
Gordon to 77 degrees at O'Neill. Scattered rain showers with some
embedded thunder gradually tracked northeast across portions of
southwest into north central Nebraska this morning into the early
afternoon. Drier air pushed in behind this early activity resulting
in the showers dissipating rather quickly ahead of the main round of
precipitation, currently developing across far northeast Colorado
into portions of the Panhandle and southwest Nebraska

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 237 PM CDT Fri Jun 30 2023

This evening and tonight...The aforementioned upper-level trough
continues it's eastward progression, becoming overhead later
tonight. The ongoing activity will push further northeastward
encompassing much of western and north central Nebraska this evening
and tonight. In regards to the severe potential, the best heating
and forcing appears to remain across northeastern Colorado into
Kansas. The environment today is less favorable for severe
weather as compared to the last few days across the area. However,
portions of far southwest Nebraska does have increased 0-6km Bulk
Shear of 30 to 45kts. Which combined with MLCAPE values of ~600
J/kg and lapse rates of 6-6.5 C/km, may be sufficient enough to
support strong to briefly severe thunderstorms. Though widespread
severe weather is not anticipated, heavy rainfall is the primary
concern with this activity. Plentiful low-level moisture combined
with PWAT values of 1 to 1.25 inches will support an environment
capable of significant rainfall rates, especially for areas across
southwest and south central Nebraska. Recent rainfall over the
last few nights has resulted in saturated ground across much of
the area which will lead to increased flooding concerns. Another
area with increased concern for flooding across the South Platte
River where high flows have been observed this past week. This
heavy rainfall threat is highlight by the WPC Excessive Rainfall
Outlook of a Slight Risk for areas generally south of Highway 2.
Total QPF values are forecast to range from a few tenths of an
inch across the Sandhills to an inch or greater across southwest
and south central Nebraska with locally heavier amounts possible.

Saturday and Saturday night...The overnight showers and embedded
thunderstorms will continue Saturday morning, gradually exiting
east through the late afternoon. Upper-level ridging centered over
the Desert Southwest will push into the area bringing more stable
air into the area. Given this, no severe threat is anticipated
with the lingering activity on Saturday. Rising heights will
promote drying and warming conditions for most locations across
the western and northern Sandhills in the wake of the exiting
activity. This will also lead to gradually clearing skies through
the afternoon into the evening as the activity exits off to our
east. High temperatures will remain below normal in the upper 70s
to low 80s with light northerly winds at 10 mph or less.

.LONG TERM...(Sunday through Friday)
Issued at 237 PM CDT Fri Jun 30 2023

A drier northwest flow aloft develops Sunday and continues into
Monday, while upper-level ridging across the Desert Southwest
continues to build into the region. High temperatures climb into the
upper 80s to low 90s on both days which is about 5 degrees above the
climatological normal for the beginning of July.

Active weather returns as abundant moisture advection from the Gulf
combines with multiple disturbances embedded within the flow aloft
and surface boundaries tracking across the area. This will result in
sufficient lifting and forcing for scattered shower and thunderstorm
chances across much of the area beginning late Monday night into the
latter end of the week. Confidence in the severe weather threat and
coverage remains low at this time given variability amongst
deterministic and ensemble solutions. Though the details remain
murky right now, the potential for another active and wet period
exists for the bulk of next week, including during the Fourth of
July holiday.

In addition to the increased potential for active weather, cooler
conditions are expected for Wednesday into Friday where high
temperatures in the 70s are forecast. In fact, both the NAEFS and
ENS ensemble guidance suggests that the mean temperature at H85 will
approach the 10th percentile of climatological percentile Wednesday
into Friday. Interestingly, for Thursday and Friday's maximum
temperature, the EFI (Extreme Forecast Index) is suggesting
increased confidence of an anomalous event, such that the SoT (Shift
of Tails) is greater than zero.

These below normal temperatures and increased precipitation
chances are further highlighted by the CPC 6-10 Day Temperature
Outlook favoring below normal temperatures and the 6-10 Day
Precipitation Outlook favoring above normal precipitation. With
the potential for an active period ahead, make sure to keep up to
date with the latest forecasts as details get ironed out with
subsequent forecasts.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 635 PM CDT Fri Jun 30 2023

Scattered thunderstorms will persist across western and north
central Nebraska tonight and tomorrow morning, before ending
tomorrow afternoon. MVFR/locally IFR will be possible in any
thunderstorms. Additionally, low stratus development is expected
across portions of central and north central Nebraska into
tomorrow morning, with a period of MVFR possible. By early
afternoon, an improvement to VFR is anticipated area wide, and
this will persist into tomorrow evening.

Winds remain variable this evening before becoming northerly
tonight and tomorrow, at around 5 to 10kts. However, gusty
erratic winds can be expected in any thunderstorms.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SYNOPSIS...Viken
SHORT TERM...Viken
LONG TERM...Viken
AVIATION...Brown

Hazardous Weather Outlook
National Weather Service North Platte NE
334 PM CDT Fri Jun 30 2023

NEZ004>010-022>029-035>038-056>059-069>071-094-012045-
Sheridan-Eastern Cherry-Keya Paha-Boyd-Brown-Rock-Holt-Garden-Grant-
Hooker-Thomas-Blaine-Loup-Garfield-Wheeler-Arthur-McPherson-Logan-
Custer-Deuel-Keith-Perkins-Lincoln-Chase-Hayes-Frontier-
Western Cherry-
334 PM CDT Fri Jun 30 2023 /234 PM MDT Fri Jun 30 2023/

This Hazardous Weather Outlook is for central Nebraska, north
central Nebraska, panhandle Nebraska, southwest Nebraska and west
central Nebraska.

.DAY ONE...Tonight.

Scattered thunderstorms are expected tonight into Saturday morning.
The overall threat for severe weather is low but locally heavy rain
will be of concern.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Severe thunderstorms will again become possible Tuesday evening as a
warm, humid airmass will be in place as a cold front moves into the
area.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Taylor