Area Forecast Discussion
Issued by NWS Amarillo, TX

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FXUS64 KAMA 271144 AAA
AFDAMA

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
544 AM CST Mon Feb 27 2017

.AVIATION...
For the 12Z TAFs, a surface trof of low pressure will organize and
deepen over eastern CO and eastern NM today. The corresponding
tight pressure gradient will result in an increase in southwest
surface winds with gusts by late this morning and continuing
through the afternoon hours. Winds will diminish near sunset this
evening. An increase in high level clouds is anticipated Monday
night across the area.

Andrade

&&

.PREV DISCUSSION... /Issued 509 AM CST Mon Feb 27 2017/

DISCUSSION...
Upper level analysis reveals deepening trough over the Pac NW with
strong westerly flow over the desert SW. Dry air aloft is making
its way over the southern Rockies and moving into the TX/OK
Panhandles as a 500mb jet streak. The strongest winds associated
with this jet are expected to move just north of the OK Panhandle
per medium and short range deterministic guidance. However...a 35
to 45 knot 700mb jet is progged to move over the western
Panhandles today and with mixing up to near 700mb below a strong
subsidence inversion, breezy to windy conditions are expected
especially in the western Panhandles. SW winds around 15 to 25
knots sustained combined with afternoon minimum RH values around
10 to 15 percent in the western zones will lead to critical fire
weather conditions with elevated conditions in the eastern zones.

The Pac NW upper trough will broaden as it phases with the
southern stream flow going into Tuesday. A very strong mid level
jet will move across the Panhandles along with very strong low
level flow. The main 700mb and 500mb jet oriented from SW to NE
will be positioned across the SE half of the TX/OK Panhandles by
Tuesday afternoon. In response, surface cyclogenesis is progged
to occur rapidly with a strong surface low over the OK Panhandle
by 18z. While this will most likely have a mitigating affect on
wind speeds near the low, winds will increase as pressure
gradients tighten across the Texas Panhandle. At this time, very
strong winds are expected and look to be the main headline for
Tuesday across most of the Texas Panhandle, with the strongest
winds across the west, south and central Texas Panhandle. A high
wind watch will continue for these areas. Wind speeds sustained
over 40 knots with gusts over 50 knots will be possible in the
watch area. Fire weather will also be a big concern, however there
are some uncertainties which could have an effect on winds and
especially relative humidity. One uncertainty is the presence of
a potentially thick layer of mid and upper level cloud cover. The
GFS is very aggressive with this with no CAPE inverted-V type
model sounding profiles by 21z. The NAM brings in a similar
solution across the area with Pacific moisture coming in a few
hours later and with stronger height falls leading to elevated
CAPE (less than 100 J/kg, perhaps leading to some Virga). As
such... not thinking clouds will have a large effect on wind
speeds due to strength of winds between 850mb to 600mb where
mixing is expected to occur. Even if mixing is limited to 700mb
winds should still be strong enough to meet criteria. However, a
few degrees lower in max temperature with models already showing
dew points in the 20s and 30s will result in marginal min RH
values at best for elevated to critical fire weather. Will
maintain current headlines based on overall pattern support but
upcoming shifts will want to consider possible updates if
warranted in future packages.

Winds will begin to decrease Tuesday evening as decoupling occurs
around sunset. As the surface low pushes east, an attendant cold
front will move through the Panhandles during the late afternoon
and evening Tuesday. Can`t rule out a rain shower ahead of the
front, perhaps even convective in nature. Thunder seems very
unlikely given mid level lapse rates, but may be something to
watch. Decent CAA is expected behind the front as temperatures
drop into the 20s and 30s by Wed morning along with 10 to 20 knot
wind speeds. Temperatures will top out in the 50s for most of the
area on Wed. The upper trough will slide east leaving the
Panhandles in NW flow aloft through Wednesday.

Split flow is expected going towards the end of the week across
the CONUS with the Panhandles under mostly zonal flow. Dry
conditions are expected in the extended with a warming trend into
the weekend. Well above average temperatures are expected Saturday
and Sunday with a cold front late Sunday into Monday.

Ward

FIRE WEATHER...
Critical fire weather conditions are expected this afternoon
across the western Texas and Oklahoma Panhandles. Southwest winds
around 15 to 30 mph along with min RH values around 10 to 15
percent are expected. Further east, elevated conditions are
expected. SW winds around 10 to 20 mph along with 15 to 20
percent min RH values. A Red Flag Warning has been issued for
the western TX/OK Panhandles while a Fire Danger Statement has
been issued for the eastern Texas and Oklahoma Panhandles.

Elevated to near critical fire weather is expected on Tuesday.
Southwest winds will be strong to very strong especially across
the western, central and southern Texas Panhandle. Min RH values
are where the biggest question lies as mid level clouds could be a
limitation. See main discussion for more information. For now
maintain fire weather watch on Tuesday due to overall pattern
support and current RH values still within range of criteria.

Some limited areas of elevated fire weather are possible on
Wednesday afternoon, with more widespread elevated to critical
conditions possible Friday, Saturday and Sunday.

Ward

&&

.AMA Watches/Warnings/Advisories...
TX...Fire Weather Watch from Tuesday morning through Tuesday evening
     for the following zones: Armstrong...Carson...
     Collingsworth...Dallam...Deaf Smith...Donley...Gray...
     Hansford...Hartley...Hemphill...Hutchinson...Lipscomb...
     Moore...Ochiltree...Oldham...Potter...Randall...Roberts...
     Sherman...Wheeler.

     Red Flag Warning from noon today to 7 PM CST this evening for
     the following zones: Dallam...Deaf Smith...Hartley...
     Moore...Oldham...Potter...Randall...Sherman.

     High Wind Watch from Tuesday morning through Tuesday evening for
     the following zones: Armstrong...Carson...Collingsworth...
     Deaf Smith...Donley...Gray...Oldham...Potter...Randall...
     Wheeler.

OK...Fire Weather Watch from Tuesday morning through Tuesday evening
     for the following zones: Beaver...Cimarron...Texas.

     Red Flag Warning from noon today to 7 PM CST this evening for
     the following zones: Cimarron...Texas.


&&

$$


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