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afdfwd

Area forecast discussion
National Weather Service Fort Worth Texas
539 am CST Thu Feb 23 2017

Aviation...
VFR conditions will prevail through the period. Light south winds
are in place this morning but stronger winds are present within the
lowest 1-1.5 kft. The fws VAD wind profile actually suggests low level wind shear
of around 25 kts is occurring in the lowest few hundred feet above ground level.
However, the forward morning sounding (in progress) indicated lower
wind speeds in this layer and therefore have continued to omit a
low level wind shear mention from the tafs.

South winds will increase in speed today with gusts of 20-25 kts
possible during the afternoon. Winds will decrease in speed this
evening before they become more westerly after midnight. A dry
cold front will move through the taf sites Friday morning causing
winds to become northwesterly.

-Stalley

&&



Previous discussion... /issued 353 am CST Thu Feb 23 2017/
North Texas currently remains between two upper level systems
with an upper level trough now crossing the intermountain west.
This system is already inducing Lee-side cyclogenesis, and our
local winds will increase in response. Increasing south to west
winds from the surface up through the atmospheric column will
result in a hot and windy day across the region. Afternoon highs
will be in the mid 80s to lower 90s, with a record-setting high
temperature expected at dfw. Today's forecasted high of 90 degrees
at dfw would break the previous record of 86 degrees set in 1933.
Waco could potentially approach its record high of 89 degrees set
in 1996, but the current forecast is just shy of the record.

In addition to the record heat, elevated to near critical fire
weather concerns are expected this afternoon across much of the
region. The combination of hot temperatures, afternoon winds of
15-20 mph and humidity values below 30 percent could result in
combustible conditions today, but recent rainfall is expected to
temper the fire weather danger. However, we recognize that not
every location has received the same amount of rainfall this past
week, and some locations remain drier than others. Of particular
concern this afternoon will be areas west of Interstate 35 where
relative humidity values will fall into the teens. As a dryline moves into this
area this afternoon, there may be a slight relaxing to the winds,
but speeds are still expected to remain borderline. After
coordination with partners and neighbors, will highlight roughly
the western 2/3rds of the region with a grass fire danger
statement.

A cold front will move through the region overnight tonight with
drier and cooler air continuing to usher into the region on
Friday. However, highs on Friday across central Texas will still
manage to creep into the 70s, with highs in the 60s elsewhere.
Some elevated fire weather concerns will also exist on Friday due
to northwest winds near 15 mph, above normal temperatures, and
humidity values in the teens and 20s. A reinforcing shot of cool
air will allow overnight lows by Saturday morning to fall into the
30s and 40s. Some locations in our northwest will likely approach
freezing, but as previously mentioned, winds of 5-10 mph should
prevent frost from forming. Saturday will be a cool day with highs
in the 50s and lower 60s.

As we enter the beginning of next week, uncertainty in the
forecast increases due to changes in the models over the past 24
hours and discrepancies between the models. The models are in
decent agreement for Sunday but start to diverge after that. Return
flow will begin on Sunday, resulting in a mild day but with
rapidly increasing dewpoints into the 50s and even 60s. The
increase in moisture combined with another fast moving shortwave
through the plains will likely generate some showers and
thunderstorms and will maintain a low chance for rain across
roughly the eastern 2/3rds of the region. On Sunday night, a
dryline to our west is expected to be pulled across the region as
the shortwave departs the plains. The GFS and Canadian swing a
front in right behind the dryline Sunday night/Monday morning, but
the European model (ecmwf) stalls the dryline across our eastern counties and
keeps the front to our north. The European model (ecmwf) returns the dryline west
Monday and Monday night in response to another upper level trough
crossing the western conus, and then develops more showers and
storms with the dryline on Tuesday and Tuesday night as this next
system moves east. Since the Canadian and GFS had already pushed
the dryline through the region, they are notably drier in terms of
precipitation Tuesday, but still have some moisture return and
low chances for precipitation in our eastern counties. On the
heels of this system, it still looks like a cold front will move
through the region on Wednesday, cooling US off for the end of the
week.

Differences between the dryline/front positions early next week
with have implications on rain chances and any potential severe
weather threat. With the fast return flow and large scale lift on
Sunday, there may be at least a low severe weather threat but at
this time the amount of instability is in question. If the
dryline/front does not make it completely through the region
Sunday night and Monday like the European model (ecmwf) suggests, the potential
for severe weather may increase Monday and possibly Tuesday as
the Euro suggests increasing instability during this time. We
will continue to watch for more consistency between the models to
refine this part of the forecast.

Jldunn

&&




Preliminary point temps/pops...
Dallas-ft. Worth 90 52 68 37 57 / 0 5 0 0 0
Waco 86 50 72 37 60 / 0 5 5 0 0
Paris 84 52 67 36 55 / 0 5 0 0 0
Denton 89 47 66 33 55 / 0 0 0 0 0
McKinney 88 50 67 35 56 / 0 5 0 0 0
Dallas 89 54 69 38 57 / 0 5 0 0 0
Terrell 86 52 69 38 57 / 0 5 0 0 0
Corsicana 87 53 71 40 59 / 0 5 5 0 0
Temple 87 52 74 38 61 / 0 5 5 0 0
Mineral Wells 91 45 67 33 57 / 0 0 0 0 0

&&

Forward watches/warnings/advisories...
none.
&&

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