467
FXUS63 KGID 210602
AFDGID

Area Forecast Discussion
National Weather Service Hastings NE
102 AM CDT Sat Sep 21 2024

...Aviation Update...

.KEY MESSAGES...

*  Rain will increase across the area Saturday afternoon but
   especially Saturday night through Sunday morning.

*  Rainfall totals are generally expected to be the highest
   across north central Kansas where amounts could be around
   1.50 inches.

*  The coolest day of the forecast will be on Sunday with highs
   mostly in the 50s. Temperatures will gradually warm
   beginning Monday.

&&

.DISCUSSION...
Issued at 338 PM CDT Fri Sep 20 2024

Today and tonight...

An upper low/trough is centered over Southern California, and
an upper ridge is over the southern Plains. Another upper trough
centered over Canada extends from the Pacific Northwest to the
upper Midwest. Winds are mostly out of the south across south
central and central Nebraska and north central Kansas. High
temperatures today will generally range from the upper 80s to
the lower 90s across the area. Temperatures tonight will range
from the upper 50s to lower 70s with light, mostly southerly
winds. A shortwave will move over the area tonight which will
increase upper lift. Dewpoints will be in the 50s and 60s
tonight. This lift and moisture will combine and result in a 15%
to around 30% chance of showers and thunderstorms this evening
through tonight. While widespread severe weather is not
expected, a few storms have the potential (30% or less chance)
to become marginally severe this evening into tonight. Hail up
to the size of quarters and wind gusts up to 60 mph will be the
main threats with these storms.

Saturday through Sunday night...

A cold front associated with the upper trough centered over
Canada as it moves eastward will push into the area on Saturday.
Gusty, northerly winds are expected behind this front. Rain and
storms will continue on Saturday and will mainly be along the
front. There is a low chance (20% or less) that some of the
storms may become strong to severe on Saturday along and just
ahead of the front. The air will become more stable behind the
front as the cooler airmass moves into the area. High
temperatures on Saturday will range from the low/mid 70s to the
mid 80s. The upper low/trough to the west will begin moving over
the central Plains Saturday night. This will increase upper
lift over south central and central Nebraska and north central
Kansas which will result in more precipitation. Low temperatures
Saturday night will generally range from the upper 40s to mid
50s.

The precipitation will continue into Sunday, primarily
affecting locations along and south of the Tri-Cities area.
North central Kansas is expected to have the highest rainfall
amounts where some areas could receive up to around 1.50 inches.
The Nebraska Tri-Cities area could get rainfall amounts up to
around 0.75 inches. Temperatures will be much cooler on Sunday
across south central and central Nebraska and north central
Kansas with highs mostly in the 50s. Precipitation is expected
to begin to decrease during the afternoon on Sunday and will
continue to decrease Sunday evening and night. Low Temperatures
Sunday night will mostly be in the 40s.

Monday through Thursday night...

The upper trough overhead will begin to pass to the east of the
area on Monday with southerly winds returning. Temperatures on
Monday will warm up some from the previous day with highs mostly
in the 60s and clearing skies. Low temperatures will again be
in the 40s on Monday night. Another upper trough will move over
the region on Tuesday with high temperatures ranging from the
upper 60s to lower 70s. Temperatures Tuesday night will warm up
slightly with lows in the mid 40s to lower 50s. The upper trough
will dig southeastward with the area generally under the
backside of the upper low. Temperatures will continue to
gradually warm up Wednesday through Thursday night with highs on
Thursday in the 70s and lows Thursday night in the 50s.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 101 AM CDT Sat Sep 21 2024

For KGRI/KEAR Airports:
- Ceiling/visibility/precipitation/thunderstorm potential:
High confidence in VFR ceiling/visibility through at least the
vast majority of the period, with the only foreseeable possible
"catch" being an outside chance of brief sub-VFR visibility if
any heavier showers/thunderstorms happen to pass directly
overhead late in the period Saturday evening. Otherwise, most of
the period will feature only varying degrees of high cirrus,
before a lower (but still VFR) ceiling roughly around 8K ft.
becomes more probable Saturday evening. As for the
aforementioned shower/thunderstorm potential, largely maintained
continuity with previous TAFs by starting a mention at 23Z, but
did go with "vicinity thunderstorm" (VCTS) instead of VCSH as
there will be enough elevated instability for a few non-severe
storms.

- Winds:
This is actually the "main story" of the period, as a well-
defined cold front will slice into the area Saturday daytime and
result in a pronounced directional switch to northerly and an
uptick in speeds. Starting out early this morning, sustained
southerlies around 10KT will prevail. Then, after sunrise
direction will briefly turn westerly before the main frontal
surge arrives (currently aimed around 15Z), switching winds
northerly with sustained speeds commonly around 20KT/gusts
25-30KT through much of the day. Saturday evening, northerly
speeds will slacken some what, but gust potential to around 20KT
will remain.

One last wind-related note: There could be a brief (2-3 hour)
period of marginally-strong low level wind shear (LLWS) early
this morning (mainly 07-10Z), but have deemed this too brief in
nature/too marginal in magnitude for formal TAF inclusion.

&&

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

&&

$$

DISCUSSION...Schuldt
AVIATION...Pfannkuch