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Area forecast discussion 
National Weather Service Fort Worth Texas
846 PM CDT Tuesday may 5 2015

a favorable environment remains in place for widespread...and at
times heavy...rainfall across north and central Texas. Strong
upper level shortwave is pivoting across West Texas this
evening...providing good diffluence and forcing for ascent across
our area. The airmass over North Texas is quite moist now...with
precipitable waters in excess of 1.5". A pronounced low level convergence line
persists near a Wichita Falls-Comanche-Lampasas line...and this
has been a focus for widespread showers and isolated thunderstorms
since late afternoon. With moist...high Theta-E air feeding
northward parallel to this line...would continue to expect periods
of heavy rain in many areas along and west of I-35 overnight. So
far rain rates have not been sufficient to warrant consideration
of flash flood watches or warnings. This entire
area...however...will need to be monitored overnight if this broad
area coalesces into a larger-scale convective complex with heavier

Have updated the forecast grids to reflect higher probability of precipitation across
nearly all of the area...and included heavy rainfall wording in
the western zones. Made minor changes to temperatures as well.



/issued 644 PM CDT Tuesday may 5 2015/
/00z tafs/

Concerns...thunderstorms evening/overnight...MVFR stratus.

Despite showers/storms to the west/North/East...taf sites have
been generally free of precipitation today. The East Texas
activity will continue to shift eastward...moving farther away
from metroplex airports...but these cells will continue to disrupt
both inbound and outbound traffic this evening. Of greater
concern will be the activity to the west. These showers/storms
have already closed the northwest arrival gate (through Bowie
vortac)...and additional more vigorous activity this evening and
overnight should prevent its reopening. As the impulse responsible
for the ongoing storms across the Big Country approaches...the
activity to our northwest will increase in intensity and areal
coverage...aided by a 30-40kt low level jet. This inflow will provide a
continuous supply of rich Gulf moisture...and the accompanying
warm advection will maintain adequate instability to prolong the
activity much of the night. The resulting complex will primarily
impact areas west and northwest of metroplex taf sites this
evening but will eventually work its way into the metroplex around
or after 03z (10 PM cdt).

The activity will gradually push east of the metroplex by around
08z (3 am cdt). This may delay the arrival of MVFR stratus...but
with the low level jet should not be disrupted by the convection...and a
blanket of stratus should be in place in time for morning
departures. However...the showers/storms should preclude IFR

on the backside of the exiting shortwave...expect only scattered
diurnally driven showers Wednesday afternoon. Stratus will again
be slow to scatter...and low VFR ceilings may linger much of the
afternoon. As a result...expect MVFR stratus will make a quicker
return Wednesday evening.

after a rather quiet day...a few late developing showers will
occur in central Texas this evening. The thunderstorm near Fort
Hood will likely miss Waco to the west...but the activity in the
Austin area may impact Waco after 03z (10 PM cdt). With less
precipitation disrupting the invasion of nocturnal stratus
tonight...there will be a greater chance of IFR ceilings around



Previous discussion... /issued 230 PM CDT Tuesday may 5 2015/
a pattern of unsettled weather will exist over the region through
the weekend as upper systems approach from the west and move
northeast through the central rockies and Central Plains.

The first system is moving out of The Four Corners this afternoon
with a vigorous short wave pivoting into western Oklahoma and
North Texas this evening. Early afternoon Southern Plains radar
mosaic shows bands of convection feeding into this system as well
as another band of low level warm advection convection over East
Texas. As the afternoon progresses...we expect the western
convection to spread farther east into the County Warning Area with an increase in
coverage and intensity. We have a very unstable atmosphere in
place and strong upper diffluence approaching from the west that
will tap into high Theta-E air riding north on a 30-40 knot low
level jet...thus some strong to marginally severe storms are
possible through middle evening. Also...echo training could lead to
isolated heavy runoff that could produce localize flash flooding.

As the upper system moves farther away from the region on
Wednesday...we expect a lull in organized convection Wednesday
through Thursday night. However...there will be isolated to
scattered activity...mainly driven by nocturnal warm advection at
night and daytime heating each afternoon.

The second system will move down the West Coast Wednesday and Thursday
and into the Desert Southwest on Friday and over the southern/central
rockies this weekend. Once again...this system will spread strong
upper dynamics over the region over the weekend while low level
moisture continues to feed northward on a strong low level jet.
Actually...low level Theta-E...surface to 850mb...will be slightly higher
than those expected tonight. Forecast soundings and hodographs
for the weekend period show a potential for some severe storms
forming and moving off a dryline and into the western County Warning Area...and a
potential for very heavy rainfall both Saturday and Sunday as
precipitable waters climb above the 2nd Standard deviation for early may.

A cold front will arrive on Monday and shunt the convection to the
southern County Warning Area Monday night and mainly south of the County Warning Area on Tuesday.

High temperatures will remain rather seasonal through Sunday
while overnight lows will be 4 to 9 degrees above normal.
Temperatures will turn a little cooler for Tuesday with highs
generally 75 to 80 degrees. 75


Preliminary point temps/pops...
Dallas-ft. Worth, Texas 67 82 68 82 68 / 80 20 20 20 30
Waco, Texas 67 83 69 82 69 / 70 20 20 20 20
Paris, Texas 65 79 65 80 67 / 70 30 20 30 30
Denton, Texas 66 81 67 81 68 / 80 20 30 30 30
McKinney, Texas 66 79 67 81 68 / 70 20 20 20 30
Dallas, Texas 67 81 68 82 69 / 80 20 20 20 30
Terrell, Texas 67 80 68 82 68 / 50 30 20 20 30
Corsicana, Texas 67 81 68 82 69 / 50 20 20 20 20
Temple, Texas 67 83 69 82 69 / 70 20 20 20 20
Mineral Wells, Texas 66 82 67 81 67 / 80 20 30 20 30


Forward watches/warnings/advisories...



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