837
FXUS64 KAMA 211811
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
111 PM CDT Sat Sep 21 2024

...New KEY MESSAGES, SHORT TERM, LONG TERM...

.KEY MESSAGES...
Issued at 109 PM CDT Sat Sep 21 2024

- Thunderstorms are very likely today across the Texas and
  Oklahoma Panhandles. Some of the thunderstorms could be severe,
  with the primary hazards being large hail and damaging winds. A
  tornado or two are also possible this afternoon through early
  this evening, mainly in the southwest Texas Panhandle.

- The thunderstorms today through Sunday morning could also
  produce very heavy rainfall which could lead to flash flooding,
  especially from this evening through tonight across the central
  and southern Texas Panhandle.

- A cold front will bring in much cooler temperatures on Sunday
  with highs in the 50s to 60s across the combined Panhandles.

&&

.SHORT TERM ...
(This evening through Sunday night)
Issued at 109 PM CDT Sat Sep 21 2024

The upper level low pressure system is currently over northern AZ
as of this writing. The moisture plume in between this low and
the high pressure system over central and southeastern TX can be
seen quite well at this time on GOES water vapor imagery.
Widespread showers and thunderstorms can be seen over eastern NM
entering the western combined Panhandles at this time. As well as
some isolated to scattered storms out ahead of the main convection
near Dumas and Hereford. Water vapor imagery shows quite a bit of
dry air moving along the southern fringe of the upper low. This
may come in and kill storms early than previously thought, just
after midnight in the west. However, it is hard to say how this
stream of dry air will modify as the low pressure system moves
into Colorado and possibly weakens later tonight. CAMs still show
some redevelopment of storms in the western Panhandles right
around midnight.

Seeing some breaks in the cloud cover at this time which will aid
in destabilizing the atmosphere a bit going into the afternoon
hours. Models are showing some MUCAPE around 1000 to 1500 J/Kg
during the early parts of the afternoon in the southwestern TX
Panhandle. Still unsure about the length of time that severe
storms may be possible going into this evening as models show a
sharp drop off in instability after 21Z to around 500 to 700 J/Kg.
Bulk shear will start off around 30 kts but is looking to pick up
to around 50 kts later this evening an H7 jet picks up to 30 to 40
kts after 21Z. With the current bulk shear around 30 kts, and
breaks in the clouds in the southwest a hatched hail has been
added to the southwestern TX Panhandle by SPC. If the atmosphere
doesn`t stabilize much going into the overnight hours this
increase in bulk shear may feed a couple of supercells that could
produce large hail up to 1.5" even after dark.

With continuing on and off convection or cloud cover this
afternoon, the overall tornado threat is a bit uncertain. As
storms may quickly become elevated. However, models do depict a
cold pool or out flow boundary from this morning stuff in the
northwest. This may create one if not more boundaries for some
quick spin ups if a supercell can form in the right spot along the
boundary. Confidence is not very high, but definitely don`t want
to rule out a potential tornado in the southwest to south central
TX Panhandle this afternoon. This will also depend on how much
clearing occurs over the next several hours. A model or two even
show soundings favorable for nocturnal tornadoes this evening but
this is highly conditional on the fact of where boundaries set up
and if storms can remain surface based and not become elevated
due to rain cooled air from initial storms. Anything is possible
along a boundary though with increased surface helicity. Will
state that the tor potential is low at this time with all the
caveats in place.

The main cold front with actual increase in winds and change in
pressure may not show up in the OK Panhandle till closer to
sunrise tomorrow or just before sunrise. Winds are progged to pick
up to the 20 to 25 mph range with gust up to 35 mph behind the
main push. The entire combined Panhandles should see northerly
winds up to 20 mph at least by noon tomorrow. PoPs are in place
for continued precipitation, mainly in the east for tomorrow.
However, much of the combined Panhandles may see either dry
slotting from the upper low taking place as well as the front
pushing the 50 to 60 dewpoints south out of the area ending rain
much sooner than what some models are saying.

Tomorrow Max T may very well be in the early AM hours of the
morning with temperatures cooling a couple three degrees by the
afternoon. Temperatures are looking to be in the upper 50s to
lower 60s across much of the area around 2 pm.

36

&&

.LONG TERM ...
(Monday through next Friday)
Issued at 109 PM CDT Sat Sep 21 2024

Cool temperatures progged to stick around Mon into Wed with highs
in the 70s. Thurs a warming trend may take place with more lower
to mid 80s return for daytime temperatures. Another round of
precipitation is possible starting late Mon into Tue morning.

Upper level troughing is expected to stick around keeping daytime
highs mainly below 80 Mon into Wed. Another area of low pressure
will potentially dig the present trough south into the combined
Panhandles going into Tue morning bringing some possible PVA to
help with shower and storm development. There is a bit of
uncertainty still to as how the next system will evolve and how
much moisture will be in place for an precipitation to come to
fruition. Have left NBM PoPs in for now.

Wed morning an H5 ridge may start to build in over the
Intermountain West. Depending on the eastward progression of this
ridge and strength of the upper level trough through Wed will
depend on how quickly and the strength the warmer temperatures
return to the area for Thu into next weekend.

36

&&

.AVIATION...
(18Z TAFS)
Issued at 1127 AM CDT Sat Sep 21 2024

Less than favorable conditions for flying are anticipated,
especially after 21Z. Intense thunderstorms are expected across
much of the combined Panhandles mainly between 21Z and 06Z Sunday.
These storms could produce severe hail, erratic winds, and
torrential rainfall, maybe even a short lived tornado in the
southwest TX Panhandle. The torrential rainfall may reduce
visibility as low as LIFR at times. After 06Z, storms may remain
with low CIGs still impacting conditions at the terminals. By 12Z
winds may start to shift to the north around 20 kts with higher
gusts possible through 18Z Sunday behind a front.

36

&&

.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX                57  61  44  75 /  90  30  10   0
Beaver OK                  55  59  42  71 /  90  50   0   0
Boise City OK              49  58  40  73 /  90  20   0   0
Borger TX                  57  63  45  78 /  90  40  10   0
Boys Ranch TX              56  65  43  77 /  90  20   0   0
Canyon TX                  57  62  41  75 /  90  30  10   0
Clarendon TX               63  66  48  75 /  90  60  20   0
Dalhart TX                 50  61  42  74 /  90  10   0   0
Guymon OK                  51  58  41  72 /  90  40   0   0
Hereford TX                58  64  43  78 /  90  20  10   0
Lipscomb TX                59  62  45  72 /  90  40  10   0
Pampa TX                   59  61  44  73 /  90  40  10   0
Shamrock TX                64  67  48  74 /  90  60  20   0
Wellington TX              66  70  50  76 /  80  70  30   0

&&

.AMA WATCHES/WARNINGS/ADVISORIES...
TX...Flood Watch through Sunday morning for TXZ001>004-006>009-
     011>014-016>019-317.

OK...None.
&&

$$

SHORT TERM...36
LONG TERM....36
AVIATION...36