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Area forecast discussion
National Weather Service Fort Worth Texas
425 am CDT Fri Mar 24 2017

Discussion...
a deep cyclone emerged from the southern rockies overnight. This
stretching process has intensified the circulation, which will be
inclined to move equatorward on its eastward path today.
Convection blossomed Thursday evening along the associated
dryline across the Texas Panhandle and South Plains. Winds exceed
50 knots above the boundary (invof 700mb), and with an adequate
cross-boundary component, the activity has made steady progress
east overnight, with the dryline in-Tow. However, a strong
inversion remains downstream, and the convection has steadily
diminished in intensity during the early morning hours. But the
synoptically forced motion of the dryline is peeling up the
surface layer to the east, and some showery activity is still
ongoing. The boundary layer moisture was deeply mixed across much
of North Texas on Thursday, and the instability the dryline is
encountering is proving insufficient for updrafts supportive of
lightning. But a replenishing surge of Gulf air is beginning to
arrive and will refuel the layer beneath the inversion this
morning. However, as the low-level flow veers with the decaying
convective complex, the axis of richest moist advection will
reorient itself into East Texas. The result should mean little
change in the intensity of the line until later this morning when
the convective elements begin ingesting better quality parcels
east of the I-35 corridor.

Today's pops might suggest heavier precipitation, but most areas
along and west of the I-35 corridor will see scant totals. But
with the speed of the line, even light rain will be able to spread
measurable rainfall over a considerable area. The greatest
potential for thunderstorms with brief heavy rain will be east of
the I-35 corridor from late morning through the afternoon hours.
Shear profiles suggest a linear complex will be favored with some
training of fast-moving cells in advance of the line. The Gulf
moisture will not be extraordinary for late March, and being still
early in the day, the boundary layer instability will be modest at
best. Some updrafts may be able to support hail, but the downward
transport of the strong mid-level winds will likely be the
primary hazard early this afternoon. The convection will intensify
later this afternoon, but the line should be east of our County Warning Area when
this occurs.

As the precipitation passes, dry air will surge into western
portions of North Texas. Deep mixing will allow some of the
cyclone's momentum to reach the surface, and wind gusts may
reach/exceed 40 mph again today in our far western/northwestern
zones. Downslope warming will offset the cold advection the winds
will impart, and with full sun, high temperatures will reach the
lower 80s behind the dryline. This will plunge relative humidity
values below 20 percent. Combined with the gusty winds, extreme
fire weather conditions are expected. A red flag warning has been
issued for areas along and west of a line from Sherman/Denison to
Dallas to Goldthwaite. A more westerly subset of this area, where
sustained wind speeds will be 25 mph or greater, will also be
under a Wind Advisory. Both will expire before sunset as the winds
subside.

Cold advection will ensue in earnest tonight, and temperatures
will fall into the upper 40s and lower 50s for the first time in
over a week. A mild but still pleasant day will follow, but the
early Spring chill will be short-lived. Strong south winds will
return Sunday in advance of the next storm system, and afternoon
temperatures will soar into the 80s. This trough will have a more
northerly track to its predecessor, and the best storm chances
will be well to our north. Areas north of the I-20 corridor may be
near the tail end of the convective activity. Although storm
chances have diminished, any storms that develop could become
severe late Sunday.

The subsequent system, which is still on schedule for the middle
of next week, may be the most notable within this 7-day forecast.
While there is still some disparity in timing and track among
various operational solutions (and their ensemble members), there
is considerable agreement for a system still several days out.
Most significant is the low's southerly track, potentially through
North Texas. This would tug deep tropical moisture into the
region and could provide our first significant rain event of the
Spring season.

25

&&

Aviation...
/issued 1210 am CDT Fri Mar 24 2017/
stratus will spread north from south Texas on a 50-knot low-
level jet. Expect MVFR ceilings to move into Waco 06-07z and into
the metroplex 08-09z. As an upper level trough and surface
dryline approach from the west, scattered showers and a few
thunderstorms may reach the I-35 corridor before daybreak. The
atmosphere is expected to be capped, so for now have just included
vcsh for the 11-16z period. The stratus will be quickly swept to
the east as the dryline passes. Winds will shift to the southwest
at 15-25 knots. Some gusts over 30 knots behind the dryline. The
gusts should die off toward sunset Friday. As Pacific cold front
moves through the metroplex Friday evening, winds will shift to
the west northwest at around 15 knots.

58

&&

Preliminary point temps/pops...
Dallas-ft. Worth 83 52 75 55 85 / 60 5 0 0 10
Waco 81 50 77 53 84 / 60 5 0 0 10
Paris 73 52 71 51 81 / 70 20 5 0 20
Denton 82 50 73 50 84 / 40 5 0 0 20
McKinney 77 51 72 50 83 / 60 5 0 0 20
Dallas 81 54 76 56 85 / 60 5 0 0 10
Terrell 76 51 75 52 83 / 60 10 0 0 10
Corsicana 77 52 75 55 83 / 60 10 0 0 10
Temple 81 50 78 55 84 / 60 5 0 0 10
Mineral Wells 83 49 75 52 87 / 20 5 0 0 10

&&

Forward watches/warnings/advisories...
red flag warning from 11 am this morning to 7 PM CDT this
evening for txz091>093-100>104-115>119-129>133-141>144.

Wind Advisory from 11 am this morning to 7 PM CDT this evening
for txz091-092-100>102-115>117-129>131-141.

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