045
FXUS64 KAMA 191847
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
147 PM CDT Sun May 19 2024

...New MESOSCALE UPDATE...

.MESOSCALE UPDATE FOR THE SEVERE THUNDERSTORM POTENTIAL THIS
AFTERNOON AND EVENING...Issued at 1:35 PM CDT Sun May 19 2024

Another conditional risk for severe thunderstorms is present today
for northeastern portions of the Texas and Oklahoma Panhandles. The
upper level ridge has flatten out over our area, and will allow for
a shortwave surface trough to move in from the west this afternoon.
Concerns about moisture quality and dryline placement are in place
today, but if the right conditions are met a very unstable
environment exists and will promote thunderstorms to become
strongly severe.

Mesoscale parameters...

As of late this morning, a pocket of dry air has already moved
into the southwestern quadrant of the CWA. Areas near Hereford,
Vega, and even Amarillo have had their surface dewpoints plummet
to the upper 30`s and some lower 40`s. Surrounding areas to the
north and east have still retained moisture up to this point, so
dewpoint temperatures reside in the upper 50`s and lower 60`s.
Later this afternoon, a dryline should materialize with a west-
to-east gradient and advance eastward. How quickly this occurs
has been a point of contention, since many of the CAMs and 12Z
guidance suggest the dryline should quickly mix east, and disallow
storm from growing upscale in our area. However, the 12Z NAM
products still favor a slower moving dryline and suggest storms
will become severe in our CWA before they move into western
Oklahoma and Kansas. Given that the current spread of dewpoint
values are higher than most of the guidance, a slightly slower
dryline progression is anticipated for today. This would permit
storms to initiate in our two eastern stacks of counties (Beaver
to Donley and eastward). Based off of model 0-6 km Theta-E
moisture profiles, better quality moisture will be available in
the mid to upper levels of the atmosphere. Though storm initiation
seems more probable here than what the models convey, they may be
slower to fully mature and become severe if subsidence still
prevails aloft.

Environment and hazards...

Should the full potential of our mesoscale parameters be
realized, a favorable environment exists for powerful severe
thunderstorms. This is especially true for the far northeast
Panhandles where the higher end instability and shear is placed.
Based off of LAPS data and surface observation mesoanalysis,
SBCAPE values range between 2,500- 3,500 J/kg, with MLCAPE ranging
between 1,500-2,500 J/kg. Large inverted V model soundings show
DCAPE around 1,600 J/kg. Steep lapse rates approaching 9 C/km, and
0-6 km bulk shear between 35-40 kts are also at play today. With
wind direction generally veering with height, a discrete to semi-
discrete storm mode is expected today. And provided such a large
disparity between surface temperatures and dewpoints, LCL heights
will be quite tall and high based storms are expected. The primary
hazard today will be powerful straight winds up to 80 mph and dry
microburst are possible. Large hail is also of concern today
given the very unstable air and good bulk shear. However, the
temperatures at the surface and aloft are quite warm for this time
of year, so the freezing level is much higher for any storm that
forms. Even so, 2 inch hailstones or larger cannot be ruled out.
The tornado threat for today is also low considering the high LCLs
and only modest low level shear. But if the triple point forms
further south, and with higher terrain in place, a tornado or two
is not impossible. Landspouts may also form today with any
boundary convergence, but they will have the same limiting
factors as a mesocyclonic tornado will have. In addition, 3CAPE
and enhanced stretching potential values are below the recommended
criteria for non-supercellular tornadoes.

Rangel

&&

.SHORT TERM ...
(Today through Monday night)
Issued at 308 AM CDT Sun May 19 2024

A mixed bag of potential is present today for the Panhandles as
models see the ridge getting slightly flatten by a trough moving
through to our north. This flattening will open the Panhandles up
to deal with a short wave moving through on the southern end of
the trough, which in turn will see the dry line retreat slightly
west into our area. Most models expect it to set up in our far
eastern counties this afternoon which could open those areas up to
severe weather. As it stands, many models are showing the
ingredients to make for all hazard type severe thunderstorms with
MLCAPE sitting in the 2000 to 3000 J/kg range and 0 to 1 km shear
pushing values above 30kts. However, these same models are also
showing that usage of these ingredients is going to be very
conditional with decent CIN present at the lower-levels. The
presence of this CIN is mostly due to the lack of moisture at the
low to mid level of the atmosphere. A quick look at model sounding
continues to show that all of our moisture for the afternoon
above the 500mb level, which in turn will make for very high based
thunderstorms should we get anything at all. Added to this is the
fact that shear starts to drop off greatly once you get past 3km,
with most sounding showing only straight line speed shear present
at the upper-levels. This will make it hard to keep anything high
based sustains, which, at this time, is the more likely
development given the expected LCL heights. In this case, the
bigger threat for the day may actually come an isolated
thunderstorm producing a severe wind gust rather than multiple
supercells producing hail and/or tornadoes. Given this outlook,
have chosen to keep POP reduced for the afternoon.

As for rest of the Panhandles, confidence is high that the main
threat for today will be the heat. As it stands, models are still
expecting a lee-side low to be positioned in such a way that the
Panhandles will see good downsloping southwesterly winds. The
presence of these winds have a tendency to see temperatures
increase even more than usual, which will likely result in
afternoon highs in the mid to upper 90s across the Panhandles.
This effect is further amplified in places like the Canadian River
Valley and the Palo Duro Canyon, which could easily see
temperatures in the triple digits this afternoon. The heat threat
gets even worse for Monday, as most models look for a similar set
up to be present under much drier conditions. Should this trend
continue, then it is likely that places like the Palo Duro Canyon
may need a Heat Advisory with canyon floor potentially reaching
105 by Monday evening.

Scoleri

&&

.LONG TERM ...
(Tuesday through Saturday)
Issued at 308 AM CDT Sun May 19 2024

A trough ejects from the desert SW into the plains on Tuesday
becoming the dominate feature over the panhandles. This trough
will break the spell of hot weather that baked the panhandles on
Sunday and Monday. This will see the highs on Tuesday fall to the
80s and 90s. Winds are expected to shift to the west and remain
gusty through the day. Then late on Tuesday to early on Wednesday
a cold front associated with the trough will push through the
panhandles. This will be a dry front so it will only shift the
winds to the north and not cause any active weather. Cooler air
will settle across the panhandles for Wednesday further reducing
the temperatures to the 70s and 80s. Thursday and Friday the
pattern continues to favor a shift to a zonal flow across the
southern plains. This should help to push the cooler air out of
the panhandles allowing the highs to warm back to the 80s and 90s.
Winds during this time should follow a standard diurnal trend of
gusty from the south during the day and weak during the night.
If the winds become more southeasterly then moisture may be pushed
into the panhandles leading to daytime rain showers and
thunderstorms. The odds of this occurring do not look favorable
at this time as any moisture that does move in is likely to be
east in OK proper. By next weekend the pattern becomes hard to pin
down making the forecast less confident. There are hints that a
system may form during this time and bring active weather to the
southern plains. Conversely there is a slightly smaller chance
that a ridge will form instead bringing further dry and hot
weather to the panhandles. Regardless of outcome it seem favorable
that the pattern will shift for next weekend bringing a change in
the weather compared to mid week.

SH

&&

.AVIATION...
(18Z TAFS)
Issued at 1258 PM CDT Sun May 19 2024

VFR conditions will prevail at all TAF sites over the next 24
hours. Only site anticipated to possibly have disruptions would be
KGUY in the next 6 hours, if a storm manages to pop up in the
area, but right now confidence is too low to mention in the TAF.
Winds 15-20kts out of the west southwest through about 03z then
becoming less than 10kts out of the west to northwest thereafter.

Weber

&&

.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX                59  98  63  89 /   0   0   0   0
Beaver OK                  59  97  62  90 /  10   0   0   0
Boise City OK              54  94  57  85 /   0   0   0   0
Borger TX                  60 102  65  93 /   0   0   0   0
Boys Ranch TX              55  99  61  91 /   0   0   0   0
Canyon TX                  56  97  62  89 /   0   0   0   0
Clarendon TX               60  98  65  91 /  10   0   0   0
Dalhart TX                 53  94  55  87 /   0   0   0   0
Guymon OK                  54  97  58  88 /   0   0   0   0
Hereford TX                56  98  61  89 /   0   0   0   0
Lipscomb TX                60  98  65  92 /  10   0   0   0
Pampa TX                   59  98  64  90 /  10   0   0   0
Shamrock TX                60  98  65  93 /  10   0   0   0
Wellington TX              62 100  67  94 /  10   0   0   0

&&

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

$$

SHORT TERM...11
LONG TERM....98
AVIATION...89