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000
FXUS64 KFWD 151448 AAA
AFDFWD

Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
948 AM CDT Sun Oct 15 2017


.UPDATE...
Quick update to remove the Wind Advisory and clean up PoP, Wx and
Sky grids. The remainder of the forecast remains in good shape.

The much talked about cold front has cleared our southernmost
counties at this hour per the latest surface analysis. Surface
pressure tendencies have relaxed some with RAP mesoanalysis
indicating only about 1 to at most 2 mb/hr rises out across the
Big Country. While we should still see some good mixing and
resultant momentum transfer equating to wind gusts close to 30
MPH, sustained wind speeds should remain below advisory criteria.
As a result, I went ahead and removed the Wind Advisory a few
hours ahead of schedule.

Lift associated with 925-850mb frontogenesis has decreased
dramatically as evidenced by a decline in radar echoes on the
latest mosaic imagery. There may be some subtle upglide atop the
cooler surface air resulting in a few sprinkles/showers along the
I-20 corridor, but ultimately strong dry air advection from the
north should eventually lead to a moisture starved lower
troposphere. This warrants removing thunder and nudging PoPs down
through the late morning and into the early afternoon hours, with
just a slight chance for showers (10% to 20%) along the I-20
corridor through the noontime hour.

Outside of adjusting Sky and T grids for ongoing trends, the
remainder of the short term forecast is in good shape. It looks
like it`ll feel like a true Fall day with cool and breezy
conditions across North and Central TX.

24-Bain

&&


.AVIATION... /Issued 702 AM CDT Sun Oct 15 2017/
/12Z TAFs/

Main concerns with the aviation forecasts will be MVFR cigs this
morning and timing lifting of these lower cigs later this morning.
Sustained surface winds and gusts are presenting another challenge
this morning, as well a few SHRA/TS around through 14Z.

FROPA has already occurred across DFW Metro airports this morning
with gusty northerly winds 15-25 kts with few gusts 30-35 kts at
times, as strong cold advection and associated 3-hourly pressures
rises near 5 mb/3-hrs sits just upstream. Expect these winds to
continue through 16z-18z today with MVFR cigs above FL020 rising
into low VFR between FL030-050, before scattering by 17z-18z and
after with winds sustaining 15-20 kts w/gusts 25-30 kts through
22z. Will continue with north winds 8-12 kts by this evening under
mostly SKC-SCT250 conditions, as both cold advection and strong
pressure gradient continue to wane.

For Waco, FROPA has not occurred yet, but will by 13z-14z with
gusty NW winds 15-20 kts, gusts 25-30 kts by 15z. MVFR cigs will
arrive with the initial shallow frontal surge, with a brief hour
or so of IFR possible, As the low level cold advection enhances
with the deepening frontal inversion, stronger boundary layer
winds will keep winds up through 00Z Monday, before slowly
diminishing to between 10-15 kts tonight as some surface pressure
gradient and cold advection continue. Cigs should slowly rise to
low VFR by late morning, then scatter out this afternoon as well.
Any -SHRA should be brief and last through 16Z, before subsidence
arrives behind the shortwave disturbance by midday.

05/

&&

.SHORT TERM... /Issued 319 AM CDT Sun Oct 15 2017/
/Today & Tonight/

We continue to track our expected strong surface cold front early
this morning. Currently, the cold front was located from just west
of Gainesville, to north of Alvord, to Jacksboro, to Graham and
and Possum Kingdom Reservoir. Though 2-3 hour pressure rises have
come down somewhat, they still are maxing out to between 6-6.5
mb/3 hrs from Childress, to Hobart Oklahoma, to Oklahoma City.
Observations from Wichita Falls up into Southern Oklahoma have
noted wind gusts well in excess of 40 mph at times due to not only
the shear density of the cooler airmass behind the front, but also
a very tight pressure gradient with surface pressures already near
1025mb across the Texas/Oklahoma Panhandles. In addition to the
strong cold front and expected winds, showers and isolated
thunderstorms were developing just behind the cold front, due to
isentropic ascent associated with the southern tail end of strong
shortwave energy aloft lagging behind the cold front by 50 to 100
miles. Ahead of the cold front, south winds 5 to 15 mph were
occurring with temperatures in the 70s and continued humid
conditions.

The cold front will continue to move southeast at a good clip,
about 35 to 40 mph and pass through the I-20/30 corridors,
including the Dallas-Fort Worth Metroplex during the pre-dawn
hours. The farthest southward surge will occur west of I-35/35W
through daybreak due to higher pressure rises across that region
and relatively higher terrain. We expect winds least through mid-
late morning to sustain between 25-30 mph with gusts to or in
excess of 35 mph at times, before slackening up somewhat by
afternoon. A Wind Advisory has been hoisted through 11 am CDT for
areas generally along and northwest of a line from Goldthwaite, to
Hillsboro/Corsicana, then northward up through Terrell,
Greenville, and Bonham. These areas will see the best pressure
rises and stronger winds through the morning hours. Otherwise, the
cold front will continue to readily outrun the tailing mid level
shortwave energy aloft. Elevated scattered showers and isolated
thunderstorms should continue past daybreak, as moisture and lapse
rates aloft above the deepening low level frontal inversion will
be enough to keep some hit and miss activity going this morning.
No strong or severe weather is expected.

With the shortwave dropping past the Ozarks and into the Lower
Mississippi Valley this afternoon, we should begin to see some
subsidence arriving from the northwest with better lift shifting
east of the area. In addition, the cold front will be pushing
through Southeast Texas and the Texas Upper Coast, with
increasingly drier low level airmass entraining in with the
deepening cold frontal inversion. Some sporadic cloudiness will
linger, before better clearing occurs late this afternoon and into
tonight. It will remain brisk this evening, before the winds
really diminish with clear skies assisting in radiational cooling
and decoupling and the surface high building in from the Central
Plains. Have gone below guidance on highs with the strong cold
advection, persistent cloud cover through at least early
afternoon, and spotty elevated convection around through the
morning hours. Many areas will be hard pressed to get out of the
60s, with some early highs in the 70s across the southeast
counties, with slowly falling temperatures through the day. Some
of the coldest air of the season will show up by sunrise Monday
morning. Lows well down into the lower-mid 40s will occur just
north-west of the DFW Metro, with upper 40s and lower 50s
elsewhere. A light coat or jacket is definitely advised today and
tonight if planning on heading outdoors for any prolonged period
of time.

05/

&&

.LONG TERM... /Issued 319 AM CDT Sun Oct 15 2017/
/Monday Onward/

Pleasant fall weather will be the story to begin the week with a
couple days of near- or below-normal temperatures and low
humidity. Surface high pressure will dominate much of the Central
Plains in wake Sunday`s cold front which will keep dry weather
and clear skies in place for most of the region. These conditions
will also mean a quality radiational cooling setup overnight,
especially on Tuesday morning when winds will be very light. Some
outlying areas may actually dip into the upper 30s before
daybreak Tuesday, especially across our northwestern zones. It
should be the coolest morning since April or May for most of the
forecast area.

By Wednesday, south winds will return as surface high pressure
shifts east and flow becomes fairly zonal aloft. A warming trend
will ensue, and temperatures will climb right back to near or
above normal by Wednesday afternoon. Moisture will be slow to
return however, but by Friday, 50s and low 60s dewpoints should
finally overspread much of North and Central Texas. To our west,
a few upper disturbances will be rippling through the broad
trough that should be taking shape across the western US. This may
allow for a few showers or storms within the deeper moisture
across Central Texas on Friday afternoon, thus have maintained
some low PoPs.

Models continue to be wildly inconsistent regarding the evolution
of the aforementioned upper trough to our west for next weekend.
The latest run of the ECMWF is swinging a progressive shortwave
through the region along with another cold front next Sunday,
which is a complete change from the previous run that developed a
deep retrograding cutoff low to our west. The GFS has favored a
weaker and more progressive solution, but without pulling the
front through our area. GEFS members are roughly an even split
between the operational GFS, and both solutions depicted by the
latest ECMWF runs, so confidence is quite low even regarding the
large-scale pattern for next weekend. Regardless of the exact
setup, there will be sufficient moisture in place, and one
disturbance or another should be capable of producing showers or
storms across part of the forecast area. Have maintained low PoPs
with low confidence through next weekend.

-Stalley

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    68  49  72  48  77 /  20   0   0   0   0
Waco                71  48  75  44  79 /  20   0   0   0   0
Paris               69  46  71  45  73 /  20   0   0   0   0
Denton              67  44  72  42  75 /  10   0   0   0   0
McKinney            68  45  72  43  74 /  10   0   0   0   0
Dallas              69  50  73  49  77 /  20   0   0   0   0
Terrell             70  46  75  45  76 /  20   0   0   0   0
Corsicana           71  48  72  47  77 /  20   0   0   0   0
Temple              71  49  75  46  78 /  20   0   0   0   0
Mineral Wells       67  43  71  42  77 /  20   0   0   0   0

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

24/82