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000
FXUS64 KAMA 172234
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
534 PM CDT Sat Jul 17 2021

.AVIATION...
Thunderstorms continue to pop up around the area this afternoon
and will continue going into the evening. KGUY and KDHT are
looking to become free from thunder going into this TAF period.
There is a small chance KDHT could see more thunderstorms before
06Z but have left out of the TAF due to the low confidence. KAMA
will be mostly likely impacted by at least VCTS through about 06Z.
Out side of any thunder terminals should see VFR conditions with
southerly winds around 10 kts or less.

Hoffeditz

&&

.PREV DISCUSSION... /Issued 217 PM CDT Sat Jul 17 2021/

SHORT TERM (Today through tomorrow night)...

Another couple rounds of showers/thunderstorms are forecast for
the short term. These typical summertime showers/thunderstorms
will be scattered in nature and hard to pinpoint, but generally
speaking we are not expecting widespread severe weather. We can
however get a couple rogue thunderstorms capable of producing an
isolated severe wind gust around 60 mph, and of course lightning
is a threat with any thunderstorm. Additionally, isolated
flooding may occur if a thunderstorm develops over an urban area.

High pressure will continue to build into the Four Corners region
today/tonight. This will continue our northwest flow pattern
aloft, but it becomes more northerly tomorrow as the high pushes
north of the Four Corners region into a north-to-south elongated
H5 high. We still keep the moist atmosphere in place with the
tropical airmass and high precipitable water values. In typical
summertime fashion, our mean flow is rather weak with little
shear. Thunderstorms are going to be very pulsy and experience
very slow storm motion as updrafts struggle to maintain.

For today, the northwest flow and embedded impulses will make for
our better chances of more widespread rainfall across the
Panhandles. As we reach convective temperatures later today, look
for scattered pop-up thunderstorms to form across the north and
northwest and even off the higher terrain across eastern NM,
eventually pushing east and south through the evening. Storms will
exhibit slow motion, so any storms that form over urban areas
will have a chance for flooding given the high PWATs. Early on,
with the inverted-v soundings anticipated, we could have
evaporative cooling processes created damaging wind gusts as
storms collapse. There are pockets of 1000-1500 J/kg MLCAPE, so we
could have hail develop, but the weak shear will not allow for
strong updrafts, so we could have more of an accumulating hail
threat with small stones not quite getting to severe criteria of
1.0"+ in diameter. So, main threats today will be localized
flooding and damaging wind gusts.

For tomorrow, there is a lot of uncertainty and we could end up
drier than what we have forecast. The atmosphere may work itself
over through the overnight period tonight, and make for
unfavorable conditions for storms tomorrow. The NAM Nest has been
performing well lately with these summertime thunderstorms, and it
keeps us mostly dry for tomorrow. Of course, this is just one
output, as the National Blend of Models paints 30-40 percent
across most of the area. If we end up with mostly subsidence
aloft and the absence of any outflow boundaries to work with, we
could be over forecasting PoPs for tomorrow. A lot will depend on
today/tonight, but with that said we are looking at a very similar
story for any showers/thunderstorms that develop regarding weak
shear, slow storm movement, and the tropical airmass. Threats will
be similar with damaging wind gusts and localized flooding as the
main impacts. Confidence for precipitation timing and coverage is
low at this time given the uncertainty.

Guerrero

LONG TERM...Monday through Friday...

The beginning of the long term will continue the pattern of below
average temperatures and chances for storms. Looking towards
later in the week, a return to near normal temperatures is
expected along with drier conditions.

An upper level ridge continues to build across the western CONUS
on Monday, keeping the area under northerly flow aloft. A H500
shortwave beginning across the Northern Plains, is forecast to
move south across the Southern Plains on Monday afternoon through
the evening. This shortwave will likely support initiation of
thunderstorms on Monday evening across the area. The thunderstorms
may continue into Tuesday, with a weak upper level low pressure
system attempting to undercut the ridge over northern Texas. If
there are storms on Tuesday, they likely will be confined to the
southern Texas Panhandle. Upper level support will continue to be
weak, so organized severe weather is not expected at this time.

The ridge with associated high pressure is expected to move
slowly towards the east through the extended period, with the
center of high pressure mainly across the Central Plains. By
Friday, the ridge is forecast to expand across the Southern
Plains, which will lead to increasing high temperatures and
continued dry conditions through the end of the period.

Muscha/Ward

&&

.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.

&&

$$

36/89