082
FXUS64 KAMA 191946
AFDAMA

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

...New SHORT TERM, LONG TERM...

.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...
(This evening through Monday night)
Issued at 211 PM CDT Sun May 19 2024

A Severe Thunderstorm Watch is in effect for the
northeast Panhandles through 10 PM this evening.

Afternoon showers and storms will be possible today. See the
Mesoscale Update above for details regarding today`s severe
potential. Tonight, the dryline will attempt to retreat to the
east, but another surface low is expected to track across the
Panhandles and hold it in place. Tomorrow, we`ll still have warm
southwest flow aloft over the Panhandles and with another lee
surface low setting up in southeast CO we can expect very dry
conditions with RH values in the 5 to 10 percent range. Winds
expected to be in the 15-25 mph range, which will support
elevated to maybe some brief critical Fire Weather conditions.
Mild overnight lows on Monday night with lows in the upper 50s to
mid 60s.

&&

.LONG TERM...
(Tuesday through next Saturday)
Issued at 211 PM CDT Sun May 19 2024

Tuesday will be similar to Monday as we`ll still be under
Southwest flow, but there will be a weak frontal system from the
upper trough that`s expected to push through. Overall, the main
front is expected to come overnight Tuesday night and will cool
the Panhandles down into the 80s on Wednesday. Given that the
trough is pretty quick to eject to the northeast as another upper
trough swings down front he Pacific Northwest, we can expect
Thursday to be under a more zonal to southwest flow, with a
potential dryline setup again in the eastern Panhandles. Models
area back and forth regarding where storms would initiate on
Thursday, but the potential is still there for the eastern
Panhandles. While confidence is low, if storms develop they have
a decent chance to be severe, but again it`s still uncertain if
things will even materialize in our area this far out. Upper
trough axis is still well displaced to the north and quickly exits
to the east with zonal flow returning on Friday and Saturday
leaving the area with highs in the mid 80s to lower 90s. Possible
shortwave that could trigger another round of storms in the
extended, but no confidence at this time for the forecast.

Weber

&&

.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                59 100  63  90 /   0   0   0   0
Beaver OK                  57  99  62  92 /  10   0   0   0
Boise City OK              54  93  57  85 /   0   0   0   0
Borger TX                  60 103  65  94 /   0   0   0   0
Boys Ranch TX              55 100  61  91 /   0   0   0   0
Canyon TX                  56  99  62  90 /   0   0   0   0
Clarendon TX               60  98  64  91 /  10   0   0   0
Dalhart TX                 53  94  55  87 /   0   0   0   0
Guymon OK                  53  96  59  89 /   0   0   0   0
Hereford TX                56 101  60  91 /   0   0   0   0
Lipscomb TX                60  97  64  93 /  10   0   0   0
Pampa TX                   60 100  64  91 /  10   0   0   0
Shamrock TX                60  98  65  93 /  10   0   0   0
Wellington TX              60  98  66  96 /  10   0   0   0

&&

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

$$

SHORT TERM...89
LONG TERM....89
AVIATION...89