FXUS64 KFWD 200259

Area Forecast Discussion
National Weather Service Fort Worth TX
959 PM CDT Wed Sep 19 2018

Only significant change to the forecast this evening was to
extend the mention of isolated thunderstorms and low PoPs into
the overnight hours across our far eastern zones. A batch of
decaying convection continues to meander from roughly Tyler to
Sulphur Springs, and an isolated shower or storm may affect areas
east of a Greenville to Palestine line through 1 AM or so.
Otherwise, the forecast is in good shape and have only made minor
changes to account for temperature/sky trends. Products for this
update have already been transmitted.



.AVIATION... /Issued 654 PM CDT Wed Sep 19 2018/
/00Z TAFs/

No aviation concerns are expected tonight across all TAF sites.
Southerly winds around 10 to 13 knots will prevail through the
forecast period. Increasing moisture will result in increasing
MVFR cloud cover by Thursday morning across Central Texas. Cloud
bases are expected to be above FL020. Ceilings should improve to
BKN VFR after 20Z. While showers and isolated thunderstorms may
develop Thursday afternoon across Central Texas, confidence is too
low to mention VCSH/VCTS with this TAF issuance. For the
Metroplex TAF sites...VFR will prevail through the forecast
period, but I can`t rule out a few pockets of scattered MVFR

Beyond the forecast period, cloud cover and rain chances will
continue to increase.



.SHORT TERM... /Issued 400 PM CDT Wed Sep 19 2018/
/Through Tonight/

Similar to yesterday, upper ridging remains in control of North
Texas weather resulting in hot conditions and very low coverage of
showers across the region. The only precipitation around the area
is across East Texas where a few spotty showers have developed
over the last hour. A few of these could make it into our far
eastern counties before the sun goes down this evening. Coverage
should be less than 10%.

Changes are on the way though as our upper ridging is currently in
the process of shifting eastward and a weak mid level disturbance
moves out of northern Mexico. While we`re not expecting any
precipitation tonight, total column moisture will be on the
increase and we should start to see some increased cloud cover
across deep South Texas spreading northward into Central Texas by
morning. Overnight lows will remain in the low to mid 70s with
southerly winds around 10 mph.



.LONG TERM... /Issued 400 PM CDT Wed Sep 19 2018/
/Thursday Through the Middle of Next Week/

An upper trough racing through the Intermountain West will emerge
from the Rockies on Thursday, pushing our anticyclone to the east
and bringing an end to our recent bout of late summer heat and
humidity. Initially, the TUTT currently over Deep South Texas will
attempt to take its place, returning rain chances to Central Texas
as early as Thursday afternoon. Deep southerly flow beneath the
upper low may try to push the northern extent of the activity, but
the paucity of this steering flow should keep the convection
confined to areas south of I-20 before sunset.

The mid-latitude trough in the West is ingesting Pacific moisture
from Tropical Depression 19-E in the Gulf of California, and this
plume into the Four Corners has already helped thunderstorms
develop across Arizona and New Mexico. As TD 19-E ejects across
the Sierra Madre Occidental, more widespread showers and
thunderstorms are expected from Chihuahua into New Mexico and West
Texas on Thursday. The bulk of the activity will remain to our
west Thursday night, but as large-scale forcing for ascent
advances from the west, additional showers and storms will develop
across western North Texas early Friday. Even if a complex to our
west doesn`t survive the night, deep moisture will surge
northward, and new development will easily take its place during
the day Friday. By Friday afternoon, precipitable water values
will be in excess of 2 inches across our entire CWA and may
approach Fort Worth`s late-September record of 2.31", enhancing
the heavy rain potential.

Widespread cloud cover will limit surface heating, but the rich
moisture and lift will assure convective initiation is unimpeded.
However, there are still uncertainties regarding the severe
potential Friday afternoon and evening. The associated surface
front will likely remain to our west, but a few strong storms
will be possible deeper into the warm sector. A relatively weak
low-level wind field and marginal shear should limit the severe
potential further away from the boundary, but this will need to be
continually monitored as the event approaches. It still appears
that heavy rain and lightning will be the primary concerns for
outdoor activities on Friday.

The tendency for echoes to train will continue Friday night into
Saturday, with subsequent rounds of heavy rain enhancing the flood
threat. Although it is difficult to pinpoint the most likely areas
to be affected, it appears the greatest cumulative totals will be
from the Dallas/Fort Worth Metroplex northward to the Red River.
The extent of any frontal intrusion is poorly resolved in the
guidance and may be largely driven by mesoscale convective
features. The ECMWF is advertising a surface low transiting the
CWA on Saturday, which would significantly enhance the severe
threat. However, it still appears that heavy rain and flooding
will be the primary concerns on Saturday.

A general weakness in the flow aloft may prevent any break in rain
chances between the weekend event and the next upper trough
arriving the middle of next week. This trough will be more
strongly amplified than its predecessor and may tug the first
significant autumn cold front into the Southern Plains.



Dallas-Ft. Worth    76  92  75  88  71 /   0   5  10  70  70
Waco                75  92  75  89  73 /   0  20  20  60  60
Paris               75  94  73  89  70 /   5  10   5  50  70
Denton              74  92  74  87  70 /   0   5  10  70  70
McKinney            75  91  74  86  70 /   5   5  10  60  70
Dallas              77  92  75  88  72 /   5   5  10  60  70
Terrell             75  94  75  91  73 /  10   5  10  50  60
Corsicana           75  91  73  88  72 /   5  10  10  60  60
Temple              74  92  74  88  73 /   0  30  20  60  50
Mineral Wells       72  91  73  85  69 /   0  10  20  70  70





NWS FWD Office Area Forecast Discussion