-- Discussion containing changed information from previous version are highlighted. --
034
FXUS64 KAMA 210531
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
1231 AM CDT Sat Sep 21 2024

...New UPDATE, AVIATION...

.UPDATE...
-- Changed Discussion --
Issued at 1226 AM CDT Sat Sep 21 2024

Showers and isolated thunderstorms continue to roll in across the
western Panhandles early this morning. This activity continues to
not be handled well by the latest hi-res models. The showers
should gradually decrease in coverage through the morning hours as
the better upper level lift moves off to the northeast. Have added
PoPs through the early morning hours across the west and central
to account for the light showers.

Muscha
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&&

.KEY MESSAGES...
Issued at 304 AM CDT Fri Sep 20 2024

- Thunderstorms will be possible today through Sunday with some
  of the storms having the potential to be severe, with damaging
  winds and large hail being the primary concern, with localized
  flooding becoming possible on Saturday.

- Cooler temperatures are likely to be present Sunday with the
  arrival of the cold front.

- Additional thunderstorm chances are forecast early to mid next
  week.

&&

.SHORT TERM ...
(This evening through Saturday night)
Issued at 230 PM CDT Fri Sep 20 2024

As of the early this afternoon, radar and satellite were already
seeing showers and thunderstorms move in with the lead wave of the
incoming upper-level system. Latest expectations for the CAMs
continues to see these showers focus mostly in the western and
northern portions of the Panhandles with potential to be present
clear into the overnight hours. In terms of impacts, CAMs have
been very confident very in little MLCAPE being present with some
of the higher outcomes still having values under 1000J/kg. The
bigger concern for the severe potential today will be more focused
on the winds as all the CAMs are suggesting DCAPE values above
1500 J/kg, which would be more then enough to create a 60 to 70
mph gust off a weak collapsing thunderstorm. Secondary to the
winds, will be the flooding potential for today as all models see
PWAT values rise above an inch today and continue to rise with the
approach of the main system. Added to this is will a very good
potential to see storms train over areas with flow staying
consistent for the day and CAMs suggesting that environment will
be favorable to recycle and redevelop storms. While this setup may
not result in quick flash flooding, it could be a case of small
amounts adding up over time, especially if storms continue into
the overnight.

Of course this overnight activity will be key to the impacts
expected for Saturday when the system arrives in full to the
Panhandles. As it stands, CAMs are in agreement that much better
MLCAPE will be present across the southwestern portions of the
Panhandles, with very good wind shear present in the area as well.
What is especially concerning, is that many of these model are
suggesting that a chunk of this strong shear is present in the
lower-level which indicate better chances for a tornadic event to
be present alongside strong severe thunderstorms. However should
activity be present through the overnight, then the above mention
conditions will struggle to come to fruition under already present
cloud cover. Alongside this caveat, will be the final placement
of the boundary accompanying the system. At this time, CAMs
suggest that it holds north enough to keep the better ingredients
present to areas south of the I-40 corridor. However, it is
entirely possible that the boundary moves further south than
expected and shifts those ingredients south alongside it. Rather,
the better chances for impacts may be on the flooding side of the
equation. Currently, model agrees that PWAT values will rise even
further Saturday, which will bring a majority of the Panhandles to
values around 1.25 to 1.5 inches. Added to this will be very
similar motion and training that is expected today with potential
for storms to last clear into Sunday. Given this and the potential
rain from the overnight tonight, it is not out of the question
for locations around to Panhandles to average precipitation
accumulations of an inch by the time we hit Sunday. Add to this
the potential for areas to localized heavier amounts due to
thunderstorms, and localize flooding has the better chances to
occur over the course of the day. Regardless, expect cooler
weather to follow this activity with the northwestern Panhandles
looking to drop into the mid 70s for high temperatures Saturday.
Meanwhile in the southeast where conditions and activity are not
as favored, temperatures could still rise into the 90s for the
day.

Scoleri

&&

.LONG TERM ...
(Sunday through next Thursday)
Issued at 230 PM CDT Fri Sep 20 2024

The mid-level trough responsible for the rain chances on Saturday is
expected to eject and become imposed within northeastern Colorado by
early Sunday morning. Concurrently, this trough`s jet streak is
progged to slide northeastward, fostering the development of a sfc
high and robust CAA into the CWA. Strong northerly flow in
conjunction with modest sfc cyclogenesis in the Permian Basin is
expected to yield robust convergence along the cold front. This
Strong convergence coupled with ample BL moisture will encourage
appreciable chances for scattered convection throughout the day on
Sunday. However, the 12z suite of deterministic models exhibit much
disparity in the degree of forward advancement of the cold front,
owed to previous days coldpool magnitude and subtleties in sfc
high strength. If the cold front advances too quickly, then the
warm- sector and thus rain chances will be confined south of the
CWA. Conversely, some deterministic members slow the progression
of the cold front, yielding decent QPF returns in the Southeastern
CWA. Moreover, flooding may also become a concern in the latter
scenario due to boundary parallel shear and tendency of training
storms. POPs ranging from the 40`s to even upper 60`s have
therefore been continued for the Eastern half of CWA, Sunday.

A brief lull of rain chances will exist on Monday, with the
exception of modest POPs across the far northwestern CWA.
Appreciable rain chances return on Tuesday afternoon as a positively-
tilted trough is progged to encroach on the Southern Plains.
Regarding rain prospects on Tuesday, Much uncertainty exists in
the degree of return flow and BL moisture. Therefore, POPs on
Tuesday have been maintained in the 30`s to lower 50`s, with some
likely adjustment with further confidence. Following Tuesday,
rain chances depress considerably as the trough departs the CWA.

Below average temperatures ranging from the upper 50`s to the upper
70`s are likely on Sunday in the wake of the cold front.
Although, some uncertainty exists in the forecasted highs
considering cloud cover and possible convection. Additionally,
Low`s in the lower 40`s are plausible early Monday morning in the
far northern FA, especially if there is little to no cloud cover.
Following Sunday High temperatures are expected to rebound to
seasonal levels in the 70`s and 80`s through Wednesday.

LNJ/SAS

&&

.AVIATION...
-- Changed Discussion --
(06Z TAFS)
Issued at 1226 AM CDT Sat Sep 21 2024

VFR conditions are forecast to start this TAF cycle. MVFR to IFR
ceilings and visibility will be possible at all sites due to
showers and thunderstorms starting around or after 18z through the
end of this TAF issuance. Winds will initially be out of the
southwest but will become northerly behind a front. Sporadic winds
with higher gusts will be possible at the sites when thunderstorms
move over the terminals. MVFR to IFR ceilings are very likely at
the sites after 00z along with continued showers and potentially
thunderstorms.

Muscha
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&&

.PRELIMINARY POINT TEMPS/POPS...
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Amarillo TX                88  59  68  46 /  70  90  40  10
Beaver OK                  87  55  66  43 /  70  90  50  10
Boise City OK              75  49  59  40 /  80  90  20   0
Borger TX                  92  59  71  45 /  80  90  40  10
Boys Ranch TX              84  57  68  44 /  80  90  30  10
Canyon TX                  88  59  69  44 /  70  90  40  10
Clarendon TX               91  62  73  47 /  50  80  60  30
Dalhart TX                 75  51  63  41 /  80  90  20   0
Guymon OK                  81  51  63  40 /  80  90  40   0
Hereford TX                87  59  69  45 /  80  90  30  10
Lipscomb TX                93  60  70  45 /  60  90  60  20
Pampa TX                   89  59  69  45 /  70  90  50  20
Shamrock TX                94  64  74  48 /  40  70  70  40
Wellington TX              96  67  79  50 /  30  60  70  40
-- End Changed Discussion --

&&

.AMA WATCHES/WARNINGS/ADVISORIES...
TX...None.
OK...None.
&&

$$

SHORT TERM...11
LONG TERM....99
AVIATION...05