Area Forecast Discussion
Issued by NWS Amarillo, TX

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FXUS64 KAMA 250444
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
1144 PM CDT TUE MAY 24 2016

.Aviation...
Clear sky expected with no visibility restrictions foreseen.  Dryline
has begun moving eastward and is now through KAMA.  Surface winds
will continue to veer to southwest overnight at KAMA and KGUY, and to
west at KDHT.  Deepening of surface trof on Wednesday will promote
southwest surface winds to gust into the 25 to 30 knot range, driving
dryline and thunderstorm threat well east of all terminals.  VFR
forecast continues next 24 hours.

Cockrell

&&

.Prev Discussion... /Issued 846 PM CDT TUE MAY 24 2016/

Mesoscale Update...
Thunderstorms that develop this afternoon were LP in nature,
especially the one near Claude in the southern Panhandle where anvil
layer winds were stronger. Another contributing factor is shallow
nature of low level moisture and very dry layer above that. Deep dry
adiabatic lapse rates contributed to very large MLCAPE although
entrainment was probably a significant factor in LP tendencies. The
most dominate/largest storm with protected updraft was able to
produce 3.5 inch diameter hail south of Perryton. This storm will
continue to have a large hail threat as it moves northeastward across
Lipscomb and into southeast Beaver County. Otherwise, the threat is
diminishing with a gradually stabilizing boundary layer and growing
convective inhibition. The Flash Flood Watch will also be canceled.

BRB

Prev Discussion... /Issued 650 PM CDT TUE MAY 24 2016/

Aviation...
All thunderstorms expected to remain east of all terminals this
evening.  Dryline near a line from Hooker to Canyon.  Southeast
surface winds will prevail this evening at KAMA and KGUY, with
southwest surface winds at KDHT.  Models predict that dryline will
advance much farther east on Wednesday with all terminals remaining
in the dry air with southwest surface winds gusting into the 25 to 30
knot range.  VFR forecast continues next 24 hours.

Cockrell

Prev Discussion... /Issued 603 PM CDT TUE MAY 24 2016/

Mesoscale Update...
Westward movement of the dryline assisted by storm outflow from the
Hansford County storm has prompted an extension of area in the
Tornado Watch. We have added Texas County Oklahoma. Surface
observation in Gruver suggest warm/buoyant surface behind outflow.
We have continued to warn on the storm moving toward Spearman
despite meager reflectivity presence. Storm top divergence has
consistently been impressive and positive CG is now becoming
strongly dominate. Based on this and the environment, this appears
to be an LP supercell, despite somewhat marginal SR anvil level
winds in the northern portion of the area. Storms should eventually
trend away from LP and the tornado threat will increase later this
evening.

BRB

Prev Discussion... /Issued 519 PM CDT TUE MAY 24 2016/

Discussion...
For this forecast issuance, the greatest attention to detail has been
focused on the short term (today and tonight). Have trended towards a
consensus of forecast guidance for later periods. Another severe
weather event is beginning to unfold across the Texas and Oklahoma
Panhandles this afternoon with a threat for very large hail, damaging
winds, and isolated tornadoes. Also expected locally heavy rainfall
over areas that have already received heavy rain in recent days will
lead to an elevated risk for flooding and flash flooding. See the
latest Tornado Watch and Flash Flood Watch products for additional
detail. The latest mesoscale update discussion has been included
under the Short Term segment below for details on today`s severe
weather threat. Beyond today`s weather, an active spring weather
pattern will see several additional chances for showers and
thunderstorms across portions of the Panhandles into early next week.
See the Long Term segment below for additional details regarding the
remainder of the week.

NF

Short Term...Today and Tonight...
19z KAMA sounding shows similar low level moisture depth as the 12z
sounding and mixing now up to just above the top of this layer and we
initially started to mix out. Hot/dry air to the west of the dryline
and attendant surface pressure falls have caused winds ahead of the
dryline to turn more southeasterly and confluence along the dryline
to increase. Sharpening dryline is setting up from just east of
Liberal to near Borger to near Amarillo. Deepening cumulus field has
formed along and behind the dryline with glaciation noted in
satellite and weak echos have recently shown up on radar from near
Fritch to just west of Tulia.

There has been little change in earlier thinking other than minor
adjustments to the position of the dryline. Also, we have a better
handle on residual boundaries across the area. The most prominent is
an outflow from overnight convection which now extends from near
Dodge City southeastward across northeast Beaver County to near
Gage. East of this (including a small portion of Beaver County) low
level shear is enhanced with slightly backed winds. This boundary is
nearly stationary. Other mesoscale features include bands of
northwest to southeast oriented enhanced cu, probably associated
with areas of enhanced low level moisture. One is oriented
downstream of developing convection near Borger. We will need to
monitor this closely for possible enhancement of low level shear in
case these enhanced cu fields are more baroclinic than they
currently appear.

Another concern is retreat of the dryline later this evening and the
potential to involve a larger portion of the central Panhandle.
Similar to last night, cool outflow from convection if it becomes
extensive enough, will augment/accelerate the retreating dryline and
may be enough for at least marginal severe threat further west
including the city of Amarillo.

BRB

Long Term...Wednesday Through Monday...
As mentioned above, an active weather pattern will remain in place
across the CONUS into early next week. Upper-level troughing will be
favored across the western CONUS with broad ridging across the
Southeastern U.S. A shortwave digging through the base of the trough
on Thursday will bring our next chance for severe weather, though the
threat should be limited to the far eastern Panhandles due to a more
dynamic dryline push as the shortwave moves overhead. Quieter weather
expected late Friday through Saturday as a shortwave ridge builds in
overhead. A cold front will also slip through on Friday, cooling
temperatures by about 5 degrees. This will slow the low-level
moisture return until Saturday night into Sunday. Guidance agrees on
a passing shortwave triggering severe thunderstorms on Sunday, when
rich moisture and sufficient heating will lead to widespread
instability across the Panhandles. Details are likely to change as
the event comes into focus, but it currently looks to be similar to
the recent events we have seen in this area. Thunderstorm chances
will remain around through Monday. Stay tuned for updates over the
next several days.

NF

&&

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

&&

$$

3/16



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