Area Forecast Discussion
Issued by NWS Amarillo, TX

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000
FXUS64 KAMA 192307
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
607 PM CDT Thu Apr 19 2018

.AVIATION...
VFR conditions will prevail for the first half of the 00Z TAF
period. Low cigs and rain showers will move in from the west mid-
morning on Friday bringing chances for IFR conditions and possible
tempo groups for LIFR conditions as the day goes on. Showers can
show up between 12Z and 15Z for KDHT and KGUY. While KAMA showers
will be later between 16Z and 19Z. Thunder still cannot be
entirely ruled out, however confidence is low and therefore left
out of the TAFS at this time. Winds will be predominately
southeast with gust 25-30 kts at times.

Hoffeditz/Cockrell

&&

.PREV DISCUSSION... /Issued 401 PM CDT Thu Apr 19 2018/

DISCUSSION...It is with great joy that I write precipitation
chances are in the forecast through early Sunday. The reason is
that an upper level low presently located over Las Vegas will
continue to move across the 4 corners region through tomorrow and
be over the New Mexico/Colorado border by Friday afternoon.
Southeasterly flow ahead of this system will help keep any dry air
from mixing down to the surface, with a stratus deck likely to set
up late tonight as the low levels begin to moisten up. Showers and
thunderstorms are expected to develop across eastern New Mexico
and the combined Panhandles starting Friday morning and continue
through the day. High-resolution models are showing that activity
that forms will do so in convective bands, with forecast soundings
showing elevated instability from H7 to H2. If the inversion layer
did not exist just below H7, I would probably be talking up our
severe weather chances given 0-1 km surface based helicities of
around 200-300 m2/s2 and a veering wind profile with 60-70 kts of
0-6 km bulk shear. But, rising parcels will instead be
originating from just above the inversion layer where wind shear
and convective instability (around 500 J/kg) are much more modest.
There may be a window Friday afternoon in the far western
Panhandles where isolated strong wind gusts could mix down from
aloft due to a drier air layer overlaying a moist environment, but
chances are low. Otherwise, showers and thunderstorms will work
with PWATs around 0.6-0.8 inches and produce periods of moderate
to locally heavy rainfall in the strongest storms.

Shower and thunderstorm activity is expected to continue on
Saturday as the upper low ejects across the northern Panhandles
through the day. As a result of mid to upper level cooling,
forecast soundings suggest that parcels should be able to rise
from the surface acting on about 500-750 J/kg of MLCAPE. The
difference from Friday will be that wind shear and relative
helicity values will be much lower, with some disorganization of
the wind profile aloft. Therefore, showers and thunderstorms
should not cause any major issues, with precipitation likely.
Precipitation chances should wind down Sunday morning with
clearing skies following. High temperatures Friday and Saturday
will be in the 40s and 50s, rising to the mid to upper 60s as a
result of clearing skies.

A break in precipitation will continue through early Tuesday, as
an upper level shortwave ridge moves across the area. A passing
short wave trough Tuesday afternoon and evening may bring a slight
chance for showers and thunderstorms as a system dives down from
the Dakotas. A ridge will move in behind it next Wednesday,
bringing drier and calmer conditions. High temperatures on Tuesday
and Wednesday should be in the upper 60s to lower 70s, which is
near seasonal norms for this time of year.

Bieda

AVIATION...Previous Discussion...18Z TAFs...

VFR conditions will prevail for the first 18-21 hours of the TAF
period before rain showers and low cigs move in from the west mid
morning Friday. For now, only included -shra at KDHT and KGUY
while leaving precip out at KAMA until next issuance. Some thunder
certainly can`t be ruled out and future issuances will have to
address this concern. Winds will be southeasterly through the
period, gusting to 25-30kt from time to time.

Simpson

FIRE WEATHER...Elevated fire weather conditions will continue
across the far western Panhandles through 8 PM this evening. Thank
you to area fire agencies for your hard work dealing with our many
weeks of fire weather conditions. You have the appreciation of the
combined Panhandles with you. Please know that, beyond today, no
other fire weather concerns are in the forecast through Wednesday
of next week.

Bieda

&&

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

&&

$$

36/3/98



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