Area Forecast Discussion
Issued by NWS Amarillo, TX

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FXUS64 KAMA 300911
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
411 AM CDT FRI SEP 30 2016

.DISCUSSION...A ridge of high pressure with main axis transitioning
east across the combined Panhandles will prevail over the region
through the late this evening. A shortwave trough is moving across
the Arizona/New Mexico border this morning, which will provide a
potential focus for showers and thunderstorms in eastern New Mexico
through the afternoon and evening hours. The GFS & NAM, along with
the Texas Tech WRF, is hinting that a vorticity max may break off
from this shortwave trough and move across the TX and OK Panhandles
late tonight and through the day on Saturday. The amount of
instability available to this vort max is not overly impressive,
around 200 to 300 J/kg, and there is very little in the way of winds
aloft to help sustain thunderstorm updrafts for appreciable periods
of time. Therefore, have opted go with a low end isolated categorical
mention of showers and thunderstorms progressing from west to east
late Friday through Saturday. Once this weak disturbance passes, the
region will dry out Sunday and early Monday as the ridge amplifies
ahead of an approaching upper low.

The progression of the Pacific Northwest low, and development of a
lee side low with associated cold front late Monday into early
Tuesday, will greatly determine the potential for severe weather
Tuesday afternoon and evening. Unfortunately, significant modeling
differences exist amongst the ECMWF, GFS, and Canadian. The ECMWF
remains the most consistent of the group, with very little difference
between the 29/12Z and 23/00Z runs, showing the upper low/trough
mainly moving staying in southern Montana and northern Wyoming Sunday
through Tuesday. The GFS has shown signs of trending towards the
latest ECMWF solutions, which was previously the model that was
showing the most favorable dynamics affecting the entire combined
Panhandles Tuesday. Meanwhile, the Canadian is much more robust with
digging the upper low into southern Utah and is suggestive of much
more favorable dynamics becoming available for any cold fronts moving
across the Panhandles early next week. Seeing as the ECMWF has been
the most consistent run, whereas the GFS has been trending towards
the ECMWF, have decided to go with the ECMWF to describe the
evolution and available dynamics for early next week.

A weak shortwave trough will eject out ahead of the main longwave
trough late Monday which could interact with a dryline draped across
the western third of the CWA. A slight chance of thunderstorms exists
Monday afternoon and evening, though only 300 to 500 J/kg of CAPE is
progged based upon forecasted temps and dewpoints. Any storms that
may form Monday could be short lived, with little concern for severe
weather. Tuesday, a low pressure system may develop across the
northern Plains, which will aid in a cold front pushing across the
region Tuesday. A dryline may set up ahead of the cold front Tuesday
afternoon, and make quick progression across the combined Panhandles
through the day. A chance of thunderstorms is progged for the eastern
portions of the combined Texas and Oklahoma Panhandles, with some
storms capable of being severe if the forecasted 1000 to 1500 J/kg
along with 40 to 50 kts of 0-6 km shear can be realized. Expect that
the dryline will clear the Panhandles around sunset on Tuesday, with
all activity being in main portion of Oklahoma Tuesday night. Once
the cold front clears the area early Wednesday, high pressure will
build into the area bringing dry weather to the region Wednesday and
Thursday.

A warming trend is expected this weekend, as a ridge aloft amplifies
over the area. High temperatures will be in the mid 70s southeast to
lower 80s northwest today, increasing 2 to 4 degrees each day with
highs on Sunday & Monday being mainly in the mid 80s throughout the
combined Panhandles. A dryline rapidly progressing eastward on
Tuesday with an associated cold front will help moderate
temperatures, with highs in the lower 80s southeast to lower 70s
northwest. Temperatures will be milder on Wednesday and Thursday,
with highs mainly in the 70s throughout the combined Panhandles.

Bieda

&&

.AVIATION...PREVIOUS DISCUSSION...06Z TAFS...VFR conditions are
expected through the entire 06Z TAF period. As we go through mid day
hours on Friday, winds will begin to pick up out of the S and SW
sustained 10-15 kts with gusts over 20 kts possible. Winds will then
subside after 00Z Saturday to near 5-10 kts. High clouds sct/bkn will
begin to work their way into the region around 00Z for KDHT/KGUY.
Otherwise, VFR conditions will continue straight through the end of
the TAf period.

Meccariello


&&

.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX                78  54  83  56  85 /   5  20  20  10   5
Beaver OK                  79  53  84  54  87 /   0  10  20  20   5
Boise City OK              81  52  82  51  83 /  10  20  20   5   0
Borger TX                  80  55  85  56  87 /   5  20  20  10   0
Boys Ranch TX              82  53  86  54  89 /   5  20  20   5   0
Canyon TX                  78  53  84  55  86 /   5  20  20   5   0
Clarendon TX               76  52  82  56  84 /   0   5  10  10   5
Dalhart TX                 82  53  85  53  88 /  10  10  10  10   0
Guymon OK                  81  54  86  54  88 /   5  20  20  10   0
Hereford TX                78  52  84  54  86 /   5  20  20   5   0
Lipscomb TX                77  53  82  55  85 /   0   5  20  20   5
Pampa TX                   76  53  83  56  85 /   0  10  20  10   5
Shamrock TX                75  52  81  55  84 /   0   5   5  10  10
Wellington TX              75  53  82  56  85 /   0   5   5  10  10

&&

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

&&

$$

98/29



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