Area Forecast Discussion
Issued by NWS Amarillo, TX

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785
FXUS64 KAMA 261459
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
959 AM CDT Wed Jul 26 2017

.UPDATE...Showers have continued to develop across the
northeastern Panhandles along an area of localized convergence.
This activity should remain isolated in nature, with more
favorable lift expected this afternoon ahead of a slowly
approaching cold front. All other aspects of the forecast remain
on track.

Bieda

&&

.PREV DISCUSSION... /Issued 559 AM CDT Wed Jul 26 2017/

AVIATION...
12Z TAF Cycle

VFR conditions will prevail at all three TAF sites through 12Z
Thursday. Showers and thunderstorms are expected to impact the
Guymon TAF site after 01Z to 03Z Thursday and then at the
Amarillo and Dalhart TAF sites after 07Z to 09Z Thursday.
Southeast to southwest winds 10 to 20 knots with some gusts to 25
knots will become east to northeast 5 to 15 knots behind a cold
front at the Guymon and Dalhart TAF sites after 02Z and 08Z
Thursday.

Schneider

PREV DISCUSSION... /Issued 320 AM CDT Wed Jul 26 2017/

DISCUSSION...
Today will be the last day with hot temperatures for the next
several days. Mostly dry weather conditions today followed by
chances of showers and storms for the next several days into next
week. This includes the risk of heavy rainfall with some areas
receiving persistent rainfall and the potential for flash
flooding.

Starting tonight, a cold front will slowly approach the northern
combined Panhandles bringing showers and storms to the region. A
low amplitude meridional pattern will limit progression southward
of the main lax gradient along the cold front. The latest 26/00Z
hi-res model output and some global model outputs have been
slowing the front`s equatorward progression throughout the
Panhandles which will delay the onset of precipitation for some
areas until later this evening into the overnight hours. The
front will enter the far northern areas late tonight and make its
way south of the TX Panhandle by tomorrow evening. Some storms
this afternoon and evening across the far northwestern Panhandles
may produce heavy rain and localized flooding. Latest 00Z GFS and
other hi-res model output are showing some indication of some low
and mid level convergence along the front and depending where
these storms generate with weak flow aloft to steer these storms,
flash flooding can become a risk. PWAT anomalies from the latest
numerical guidance of some values in the +3 to +4 S.D. range
during the day on Thursday in-conjunction with 850-500 hPa mean
flow of around 10 kts are starting to increase confidence of a
persistent heavy rainfall event. Will continue to update forecast
along as we get closer to tonight into tomorrow. With this very
moist airmass along with daytime heating, a moderate CAPE low
shear environment will be present for some storms in the afternoon
on Thursday and Friday to be strong to possibly severe,
especially in the northern Panhandles with gusty winds being a
threat. However, flash flooding will be the main threat on
Thursday into Friday.

Starting Friday night through the middle of next week, the main
upper level ridge high pressure will slowly begins to drift to the
west, centered over portions of southwestern CONUS by the weekend
and become more positively tilted by early next week. With a
deepening 250 hPa jet setting up over the central and eastern
CONUS by then, perturbations off the main jet flow to the east
will bring more chances of rainfall across the Panhandles under a
good 20-25 kts steering 500 hPa N-NW flow. This will continue to
bring several rounds of diurnal convection across the region
throughout the forecast period. Also with antecedent conditions of
heavy rainfall over the next 24-48 hours possible, this may make
more additional hazards of flooding into next week with already
saturated grounds. For temperatures, after one last day of well
above average values, temperatures will cool down to near average
throughout the rest of the forecast period for late July.

Meccariello

&&

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

&&

$$

98/7



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