Wildfire in Texas, April 12 to 13, 2018

Area Forecast Discussion
National Weather Service Lubbock TX
401 PM CDT Thu Apr 12 2018

.DISCUSSION...

...An extremely critical fire danger this afternoon and Friday
afternoon...

Strengthening and deepening southwesterly flow downstream of a
large upper-level storm system over the Great Basin is spreading a
very dry and warm airmass across the forecast area this
afternoon. 3 pm temperatures were mainly in the middle to upper
90s and West Texas Mesonet observations show a few stations in the
area have hit 100 degrees. Lubbock's record high of 96 degrees for
the date is in jeopardy. The mesonet observations also show wind
speeds of 25 to 35 mph with gusts to around 45 mph, which is in
line with the wind advisory which rungs through 10 pm this
evening. The winds will remain gusty overnight as cyclogenesis
over western KS maintains a strong pressure gradient across the
region. This in turn will lead to a very mild night with lows in
the 50s and 60s, except for some 40s in the far northwest. The
dryline is expected to make a brief return into the southern
Rolling Plains tonight but any storm chances will remain off to
the south and east.

The upper-level system will move east and emerge over the central
high plains by Friday afternoon, intensifying the lee of the
Rockies. The track and strength of this system will bring very
strong winds aloft across West Texas; an upper-level jet in
excess of 100 kts aloft and around 50 kts at 700 mb, with our
forecast area expected to be located underneath the band of the
mid-level speed max during much of the day. The result will be
wind speeds picking up quickly in the morning and continuing to be
strong through the afternoon hours. At this time it looks like
wind speeds across most of the forecast area will be on the cusp
of High Wind Warning criteria, generally in the 30 to 40 mph range
with gusts well into the 50s, possibly nearing 60 mph. Winds of
this magnitude are likely to create widespread blowing dust,
reducing visibility and making travel hazardous. The upper-level
system will be moving quickly, and as the trough axis begins to
cross into West Texas late in the afternoon, mid-level gradients
will begin to relax from NW to SE while a from moves in from the
north. This may bring some relief in the wind speeds to our north
and northwest counties. We will maintain the High Wind Watch for
our entire area at this point since the forecast wind speeds do
not look decisively in high wind category at this point and due
to some uncertainty on the timing of the front, and the duration
of strong winds across our northern counties. As heights fall with
the passing trough, temperatures will cool tomorrow, with highs
only in the 50s northwest, ranging to the upper 70s southeast.
There is a hint of some mid-level moisture arriving with the
trough across our northwest late in the day Saturday that could
lead to some light rain showers, nothing significant is expected.

A cool and dry airmass will move in behind the front Friday night
and there will be at least a light freeze across much of the
Caprock by early Saturday morning. A Freeze Watch may be issued if
this looks to be more widespread and substantial. More upper-level
energy digging along the west side of the upper-low moving across
KS will maintain gusty winds, mainly across the eastern half or
two-thirds of the forecast area. Temperatures will cool further,
with highs in the 50s and 60s.

The winds will finally die off Saturday night for a short-lived
respite. We may be flirting with minimum temperatures below
freezing late Saturday night into Sunday morning as well. After
the chilly start, Sunday should be a very nice day with highs in
the 60s and 70s and relatively light winds.

The winds will start to return Monday as flow begins to respond
to the next upper-level storm system moving inland from the West
Texas. Temperatures will warm quickly back into the 70s and 80s

As it stands now, Tuesday looks like another warm, dry and windy
day as the storm system tracks quickly to our north. The wind
speeds aloft over our area do not appear to be as strong as
tomorrow's system but could support advisory level winds.

Another weak front is expected in the wake of that system, which
again will bring some more temporary relief to the winds while
providing only modest cooling. yet another upper-level storm
system will be moving across the western states after midweek. There
are some indications this system will take a farther southward
track that could give an opportunity for moisture to return to the
forecast area late in the week.

&&

.FIRE WEATHER...
We are in a prolonged period of critical to extremely critical
fire weather conditions that will peak Friday afternoon,
coinciding with the strongest winds. RFTI values this afternoon
and Friday afternoon will be mostly in the 7-9 range due to the
combination of very low RH values and strong winds. RFTI values
this high represent an extreme threat for very dangerous fire
behavior.

A cold front will move through the area Friday afternoon and
evening, bringing a northerly wind shift which may impact fire
behavior - although it will also bring a period of lower wind
speeds. Wind speeds will increase again Saturday morning and will
likely support areas of elevated to critical fire danger across
most of the area, especially across roughly the eastern half
where the strongest winds are expected.

Sunday will bring a lull in the fire danger. However, fire
concerns will increase again Monday as dry southwest breezes pick
up. At this time, it appears that Tuesday will likely be a
critical fire weather day, as another low pressure system crosses
the high plains, spreading warm,dry and breezy conditions across
West Texas.

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 10 PM CDT this evening for TXZ021>044.

Red Flag Warning from 9 AM to 9 PM CDT Friday for TXZ021>044.

Wind Advisory until 10 PM CDT this evening for TXZ021>044.

High Wind Watch from Friday morning through Friday evening for
TXZ021>044.

&&

33

Hazardous Weather Outlook...UPDATED
National Weather Service Lubbock TX
231 PM CDT Thu Apr 12 2018

TXZ021>044-131945-
Parmer-Castro-Swisher-Briscoe-Hall-Childress-Bailey-Lamb-Hale-
Floyd-Motley-Cottle-Cochran-Hockley-Lubbock-Crosby-Dickens-King-
Yoakum-Terry-Lynn-Garza-Kent-Stonewall-
231 PM CDT Thu Apr 12 2018

This Hazardous Weather Outlook is for the South Plains...Rolling
Plains and the far Southern Texas Panhandle.

.DAY ONE...Today and Tonight

A Wind Advisory and Red Flag Warning are in effect for all areas
this afternoon and evening. Strong southwest winds will increase
to 25 to 35 mph this afternoon with gusts to around 50 mph. Areas
of blowing dust will also restrict visibilities at times.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

High winds sustained near 40 mph are expected over much of the
region on Friday with gusts to around 60 mph at times. Combined
with very dry air and expanses of dormant vegetation, volatile
wildfire behavior is likely should any fires develop. A High Wind
Watch and Red Flag Warning are in effect for all areas on Friday
afternoon and evening. Periods of thick blowing dust are also
likely on Friday, mainly throughout the South Plains. Low
temperatures may reach freezing over much of the South Plains
this weekend. Elevated to critical fire weather could redevelop
Saturday, Monday and Tuesday.