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FXUS64 KAMA 052321
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
621 PM CDT Fri Jun 5 2020

.AVIATION...00z TAF Cycle...

VFR conditions are expected to prevail through the period. There
is a very low chance for storms to move off the higher terrain
into the KDHT/KGUY area this evening. Otherwise, expect winds to
stay southerly overnight at around 10 to 15 knots. Winds will
increase late Saturday morning out of the southwest, with some
gusts around 30 knots. Finally, low level wind shear is possible
tonight, favoring KGUY through about 13z.

Ward

&&

.PREV DISCUSSION... /Issued 307 PM CDT Fri Jun 5 2020/

SHORT TERM...This Afternoon through Saturday Night...

Current WV satellite reveals an upper ridge over NM/W TX, and upper
low off the coast of S CA, an area of quasi zonal flow over the OH
Valley, low associated with TD Cristobal over the western Gulf, and
a few weak disturbances riding the ridge to our west. At the
surface, temperatures have warmed into the mainly the upper 90s
across the Panhandle, with several locations topping 100.

For this afternoon and evening, main concern is the potential for
thunderstorms as some locations may reach their convective
temperature. This will be more probable across the northern Texas
and Oklahoma Panhandles as a weak disturbance moves across and cools
the mid levels just a bit. Should a thunderstorm form, while skinny
instability profiles and 0-6km bulk shear of only around 30 knots
suggest convection will struggle to organize, substantial DCAPE of
perhaps 2000 J/kg will support strong wind gust potential with an
isolated severe wind gust also possible.

For Saturday, expect the upper low over S CA to become an open wave
as it moves over the Four Corners. With Cristobal preventing the
upper ridge sliding eastward, 500/700/850mb height gradient over
NM/CO and western Panhandles will increase. Breezy conditions will
result Saturday, especially across the northwestern Panhandles. With
the core of the 700mb jet to the west of our CWA, have opted against
the issuance of any wind headlines. However, these winds, combined
with continued dry conditions, may lead to fire weather concerns, as
detailed below. As for precipitation, while a disturbance in the
southwesterly flow aloft may kick off a few thunderstorms to our
west over NE NM, at this time convective inhibition across our west
appears to great for any storms to persist into our forecast area.

Ferguson

LONG TERM...Sunday through Thursday Night...

Looking to be hot and dry through the extended period. Main
concern will be for possible fire weather conditions Sunday and
again on Monday for the western to northwestern counties in the
FA.

By Sunday morning a mid to upper level trough will be over the
west coast of the U.S. with the ridge downstream over the mid to
upper Mississippi River Valley. South of this ridge and high
pressure is Tropical Storm Cristobal which will be over the Gulf
of Mexico approaching Louisiana. Sunday afternoon a large surface
trough to the west of the FA will create a tight pressure gradient
across the FA. Surface winds are looking to be at least 20 to 25
mph. At H85 a low level jet will set up first over the northwest
half of the FA with speeds 30 to 35 knots. Then increase going
into the over night hours to 45 to 50 kts with the entrance region
of the jet expanding over much of the FA. These winds are looking
to mix down especially in the west to northwest zones of FA, under
the left entrance region of the jet, starting late Sunday
afternoon. Surface winds could gust up to 40 mph in the afternoon,
with 30 mph, maybe higher, wind gust lasting into hours of
darkness especially in the higher terrain. Lower dewpoints in the
west and hot temperatures, upper 90's, will allow RH's to fall to
15 percent or below for the western Oklahoma Panhandle and far
western Texas Panhandle.

For Monday, winds are not looking to be quite as high as Sunday
but still nearing 20 mph. Models suggest drier dewpoints moving
into the west as the surface trough moves to the east. The NAM
and GFS even suggesting the dewpoint gradient tightening up to
form a dryline bisecting the FA. Also, these two models suggest a
triple point forming somewhere in western Kansas and eastern
Colorado. With dewpoints falling in the western FA and
temperatures reaching the low 100s, RH values are looking to drop
below 10 percent in the western stack of counties in the FA. This
will pose a threat for fire weather conditions Monday afternoon as
well. Models do not suggest any storms east of the dryline,
especially the NBM. However, MUCAPE values east of the line will
be at least 1500 J/Kg per forecast soundings from the NAM and GFS.
The NAM and GFS also suggest a nice theta-e axis at H7 setting up
along and in front of the dryline. If enough convergence can
occur at the surface and low levels a few strong to severe storms
cannot be ruled out. Have loaded and kept NBM PoPs at the moment
due to the fact that any storms will be highly conditional on the
fact that the ingredients come together at the perfect time. The
dryline could even end up in Oklahoma. If storms are capable on
Monday afternoon they will be very high based with LCL's around 3
km. Daytime highs are looking to be near or in the low 100's for
Monday afternoon.

Overnight Monday into Tuesday a cold front is progged to move
through the area. Daytime highs are looking to be kept in the 80's
for Tuesday as well as Wednesday. Winds will be out of the north
to northwest Tuesday, and no rain is expected to accompany the
frontal passage. Daytime highs will start to get back into the
90's over much of the area by Thursday and Friday.

Hoffeditz

FIRE WEATHER...

Elevated fire weather conditions are likely late Saturday morning
into the early evening hours. Increasing height gradient aloft and
surface pressure gradient will drive 20 foot winds of 20 to 35 mph
across the western Panhandles. As this occurs, expect RH values to
drop to around 15 percent, yielding RFTI values of 3 to 5. ERCs
continue to trend upward, with latest photographs of the western
Panhandles showing a decent amount of cured grasses. Recent
experience suggests fires have only needed initial attack for
suppression. Conversation with the Texas Forest Service indicates
they are not yet concerned about fires getting out of hand, even on a
breezy day, as there is still a decent amount of herbaceous
greenness mixed in with the curing fuels. Have thus opted against
issuing any fire weather headlines at this time.

Fire weather conditions will most likely exist again on Sunday
and Monday for western portions of the combined Panhandles. It is
too early to tell whether these conditions will be just elevated
or reach critical criteria. Sunday will see higher winds with 20
foot winds reaching 20 to 25 mph accompanied by higher gusts.
Relative humidity will be below 20 percent but most likely stay
above 15 percent, with the exception of a small area right along
the NM state line. On Monday afternoon, relative humidity in the
west will drop to below 10 percent, with 20 foot winds looking to
be between 15 and 20 mph. Conditions of the fuels will play a
role in possible headlines as yearly rainfall is still below
normal. Please check back for updates.

&&

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

&&

$$

7/99
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