Area Forecast Discussion
Issued by NWS Amarillo, TX

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295
FXUS64 KAMA 192330
AFDAMA

Area Forecast Discussion
National Weather Service Amarillo TX
630 PM CDT Wed Apr 19 2017

.AVIATION...
00Z TAF Cycle

VFR conditions can be expected at all three TAF sites through 00Z
Friday with mainly clear skies. High level clouds will increase
after 03Z to 06Z Thursday, with low clouds on the increase after
about 12Z to 16Z Thursday. The low clouds are expected to become
broken to overcast after 20Z to 23Z Thursday, however the ceilings
should remain in the VFR category through 00Z Friday. Winds will
shift to the northwest and north at the Dalhart and Guymon TAF
sites behind a cold front by 02Z to 04Z Thursday and will increase
to around 15 to 25 knots or 20 to 30 knots with gusts to near 35
knots until around 17Z to 22Z Thursday, and then speeds will
diminish to around 10 to 15 knots as winds become northeast to
east. The cold front will move through the Amarillo TAF site
around 05Z to 07Z Thursday and will shift the winds from the
southwest and west 15 to 25 knots with gusts near 30 knots through
around 01Z to 03Z Thursday with speeds then diminishing to 10 to
15 knots, around to the northwest and north 15 to 25 knots or 20
to 30 knots with gusts to near 35 knots after 05Z to 07Z Thursday.
Northeast to east winds can be expected at the Amarillo TAF site
20Z to 23Z Thursday 10 to 15 knots.

Schneider

&&

.PREV DISCUSSION... /Issued 523 PM CDT Wed Apr 19 2017/

DISCUSSION...

Focus for this forecast package will be on thunderstorm chances
tonight (small change for NE parts of the Panhandles) and then
Thursday night through Friday night. Breezy to windy conditions
will be realized on Friday behind a strong cold front. Outside of
this the only other impactful note weather-wise is the potential
for frost Saturday night as we have high pressure, clear skies and
light winds in place for maximum radiational cooling. Finer
details below.

For tonight, as the surface low exits east of the Panhandles, there
is a small chance for showers and thunderstorms across northeastern
parts of the Panhandles tonight. Anything that does occur should
remain below severe criteria as certain variables are lacking across
our forecast area. Instability (CAPE) values are greater across
Kansas and Oklahoma and there is a strong cap in place over our
area. Best chance for showers/thunderstorms will be between 3am
and 7am across far northeastern parts of the Panhandles. Again,
severe weather is not expected.

With around 500-1000 J/kg of most unstable CAPE and decent bulk
shear around 50-65 knots (in the higher CAPE value areas), there
is a chance for thunderstorms on Thursday night via accent through
isentropic lift. Surface triggering mechanism will not be present
due to the fact the surface features will be to the southeast.
Storms will be elevated in nature and the main threat should be
hail and wind. We should have a little break Friday morning
between the Thursday night convection and the convection
Friday/Friday night as a surface low is forecast to pass over the
Panhandles. Stronger storms Friday/Friday night should be east of
the forecast area. We could have a strong to marginally severe
storm across our east, but currently severe weather looks more
favorable east of our area, or in other words across western
parts Oklahoma.

Also to note as a result of the passing surface low on Friday is
the cold front that follows. Behind this cold front Friday
afternoon/evening there will be good mixing, a strong pressure
gradient near the front, and strong height rises (10-15mb/6hrs)
Friday night. Overall, there is a good chance we may need some
sort of wind headline to highlight this threat for strong winds
Friday/Friday night.

Saturday night high pressure will settle in over the area, and wind
speeds will be light and variable with mostly clear skies. These
conditions will maximize radiational cooling overnight and create
conditions favorable for frost formation. We are forecast to have
lows in the mid to lower 30s across a majority of the forecast
area. Since we are getting into the growing season, any sensitive
vegetation may be susceptible to frost if these conditions come
to fruition.

For the remainder of the afternoon/early evening there will be an
elevated to possibly critical fire weather risk as dry conditions
will remain in place with breezy conditions. Look for conditions
to improve soon, or close to sunset as relative humidity values
increase and wind speeds decrease.

Guerrero

&&

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

&&

$$

11



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