Area Forecast Discussion
Issued by NWS Amarillo, TX

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FXUS64 KAMA 141148 AAA

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
548 AM CST Wed Feb 14 2018

For the 12Z TAFs, southwest sfc winds will increase and become
gusty once again at the terminal sites by mid to late this
morning and continue through the afternoon hours before
diminishing some by around sunset this evening. Extensive high
level clouds along with some mid level clouds are also expected at
the TAF sites during this fcst cycle.



.PREV DISCUSSION... /Issued 443 AM CST Wed Feb 14 2018/

Current upper level analysis reveals near stationary low spinning
off the coast of southern CA while high pressure expands over the
Gulf of Mexico. Southwest flow aloft continue to pull high clouds
in as mid/high level moisture continues to feed in from the Baja
region. Deterministic models continue to show strengthening
700-500mb flow as the sub-tropical flow merges with the flow
associated with the CA upper low. The resulting mid level jet
streak of 60-80 knots will advance over the Panhandles this
afternoon. In response, a strong surface lee trough and eventual
lee low will develop in the Raton Mesa vicinity, helping to
strengthen the pressure gradient across the Panhandles. Latest
guidance has slowed the onset of stronger winds aloft, and also
the overall strength of the surface pressure gradient. That being
said, southwest winds still look to be near the windy category
today for most of the Panhandles. Also, even with the cloud cover
today, model soundings suggest strong mixing this afternoon. Thus,
temperatures will be approaching record values with highs in the
mid to upper 70s. Fire weather will be the main concern with these
conditions (see more in fire wx discussion).

The CA upper low is progged to slowly advance eastward as another
Pac NW trough digs south over the Great Basin. The CA low is
absorbed into the broad southwest flow on Thursday and the second
upper trough slows some as it`s axis tilts positive extending from
the northern plains through southern CA. This overall pattern
maintains strong mid level southwest flow over the Panhandles
through Friday morning. The combination of increasing mid level
clouds and also increasing surface dew points will help keep
Thursdays high temperatures a bit lower than Wednesday, with
mostly 60s in the west and 70s in the east. Southwest winds will
still be breezy to windy at the surface with a lee surface trough
being maintained. Unfortunately, even though there will be plenty
of clouds, it looks like the lack of low level forcing and drier
conditions near the surface will keep precip chances very low.
Guidance continues to show a surface cold front pushing through
Thursday evening and overnight, and this will represent the best
chance of squeezing out a rain or snow shower, but a lot of the
low level moisture will have already scoured out before the fronts
arrival if the latest guidance is correct. One thing we can count
on is the windy conditions for several hours along and behind the
front Thursday night into early Friday morning, and the colder
temperatures Friday.

Northwest flow aloft begins as the trough axis finally shifts
east of the Panhandles Friday. A shortwave will cross the flow
Saturday with a weak surface front that won`t amount to much more
than a wind shift Saturday morning as mild temperatures resume.
The GFS is trying to generate precip along the southeast zones
with this weak front, but this doesn`t seem likely given low level
moisture having been scoured out with the previous front. Flow
aloft gradually becomes more zonal as the next upper trough moves
into the Pac NW. Sunday should be another warm, possibly windy day
as another lee surface trough develops. Models have really
struggled in the extended periods but a stronger cold front does
look possible early next week with mostly dry conditions.


Widespread elevated with brief/spotty critical fire weather
conditions are expected across the entire Texas and Oklahoma
Panhandles this afternoon. RFTI values are currently forecasted to
be 1-2 for a good portion of the afternoon with a brief period
approaching 3 in the western Texas Panhandle. Did not issue an
Red Flag Warning at this time because latest fuels assessment
place most of the area around the 75th-89th percentile, and the
near critical conditions are not currently expected to last more
than about 1-2 hours during the early/mid afternoon as RH values
drop to 13-16 percent and twenty foot winds increase out of the
southwest at 17-20 mph, gusting to 30-33 mph. It is also thought
that the high cloud cover will limit mixing potential some.
Current 10z dew points in the southern, central and eastern Texas
Panhandle as well as the eastern Oklahoma Panhandle are in the low
to mid 30s. The increasing downslope winds will lead to drier dew
points this afternoon, but models suggest low level moisture
advection will increase dew points after about 20z-21z from
southwest to northeast. That being said, if there are some breaks
in the cloud cover or significant thinning of clouds, stronger
mixing will occur which will lead to stronger winds, warmer
temperatures, and drier dew points. Thus, fire officials should
stay up to date with the forecast today as updates may be needed.

The breezy to windy southwest winds are expected to continue
through Thursday. However, surface dew points and increased mid
clouds are expected to increase from Wednesday afternoon through
Thursday afternoon. Thus, RH values are not expected to drop quite
as low Thursday afternoon. However, it does look like elevated
fire weather conditions may develop in the northern Texas
Panhandle and Oklahoma Panhandle where conditions will be slightly
drier (RH around 20 percent). A wind shift is also expected
Thursday evening as a cold front moves through with north twenty
foot winds at 15-25 mph.

Elevated fire weather conditions are possible again on Sunday and
Monday afternoon.



.AMA Watches/Warnings/Advisories...


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