Area Forecast Discussion
Issued by NWS Dallas/Fort Worth, TX

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146
FXUS64 KFWD 241535 AAA
AFDFWD

Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
1035 AM CDT Fri Mar 24 2017

.UPDATE...
Current forecast is in decent shape and only made some minor
tweaks to PoPs through the afternoon based on latest radar trends.
Currently...a line of mainly showers continues to push eastward
through the region and is located along the I-35 corridor. This
area of convection is primarily associated with a band of very
strong low level warm advection. We continue to destabilize mainly
east of I-35 where surface dewpoints are in the low to mid 60s.
The dryline is still across the western parts of the CWA between
Mineral Wells and Graham. As we get into early afternoon,
stronger forcing for ascent is expected to spread across the
region. This combined with further destabilization should lead to
a noticeable uptick in the convective intensity. There is still a
threat for severe thunderstorms, mainly east of I-35 (specifically
from Cameron to Corsicana to Paris) through this afternoon. Most
of this activity should move east of our area by late afternoon,
although the dryline will still be positioned near I-35.
Substantial instability will be present east of the dryline into
the early evening hours, but at this time none of the high
resolution guidance develops additional convection along the
dryline. This is likely due to increasing capping associated with
an elevated mixed layer that spreads eastward this afternoon.
We`ll keep a close eye on this because if any additional storms
can develop, they would likely be severe.

Dunn

&&

.AVIATION...
/ISSUED 717 AM CDT Fri Mar 24 2017/
/12Z TAFs/

Concerns...Showers moving across the terminals this morning with
strong southwest winds after the rain/dryline. Winds shift to the
northwest this evening.

A strong upper level system is currently moving out of southeast
Colorado and will continuing moving east across the Plains today.
At the surface, a dryline is moving east across the state with a
thin line of showers ahead of the boundary moving across North
and Central Texas. These showers will impact the DFW terminals
between 13-17Z and Waco between 15-18Z. Brief MVFR cigs between
2-3 kft are possible in the showers, but otherwise VFR conditions
are expected. Saturday morning, a few clouds with bases between
1-3 kft may graze the Metroplex terminals.

As the showers move east of the airports this morning, strong
southwest winds of 15-25 kts with gusts up to 30 kts will continue
through the afternoon hours. The winds will decrease in speed a
little in the evening hours, and then will shift to the northwest
as a front passes through.

JLDunn


&&



.PREV DISCUSSION... /ISSUED 425 AM CDT Fri Mar 24 2017/
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 CWA 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



&&


.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    82  52  75  55  85 /  60   5   0   0  10
Waco                79  50  77  53  84 /  70   5   0   0  10
Paris               76  52  71  51  81 /  90  20   5   0  20
Denton              80  50  73  50  84 /  30   5   0   0  20
McKinney            79  51  72  50  83 /  70   5   0   0  20
Dallas              82  54  76  56  85 /  70   5   0   0  10
Terrell             79  51  75  52  83 /  60  10   0   0  10
Corsicana           77  52  75  55  83 /  60  10   0   0  10
Temple              82  50  78  55  84 /  70   5   0   0  10
Mineral Wells       83  49  75  52  87 /  10   5   0   0  10

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 7 PM CDT this evening for TXZ091>093-
100>104-115>119-129>133-141>144.

Wind Advisory until 7 PM CDT this evening for TXZ091-092-100>102-
115>117-129>131-141.

&&

$$



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