226 
FXUS64 KFWD 021151
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
551 AM CST Wed Dec 2 2020

...New Short Term, Aviation... 

.SHORT TERM... /NEW/
Update:
Showers are beginning to develop near and east of Interstate 45
this morning, right on schedule. Expecting coverage to continue to
increase through the morning hours east of a line from Gainesville
to DFW Airport to Waco. Other than a few fine adjustments to the
forecast, the previous forecast was left generally unchanged.

With regards to the earlier discussed Wind Advisory potential,
while a few spots could briefly hit criteria in our western
counties, it looks like it will be too marginal to warrant
advisory issuance. Still, it would be wise to secure any loose
items and exercise extreme caution on area lakes as wind gusts to
around 30 MPH will be possible.

Godwin

Previous Discussion:
/Through Wednesday night/

A developing storm system over the Southern Plains will bring
breezy conditions, increased rain and thunderstorm chances, and
another shot of cold air to our region over the next 24 hours.
Evening upper-air analysis reveals a deep trough extending from
the Canadian Prairies, through the interior CONUS, and into
Mexico. Strong diffluence within the exit region of a 100+ knot
jet streak, large differential cyclonic vorticity advection, and
low-level warm air advection will allow a surface low presently
over West Texas to deepen during the next 24 hours as it heads
east. The surface low is forecast to track near or just north of
the Red River near a zone of low-level baroclinicity. This frontal
zone demarcates the separation between a warm air advection regime
to the south where dewpoints are beginning to climb back into the
40s, and cold air advection to the northwest where a strong Arctic
high is building south across the western CONUS. The synoptic
regime to the northwest of the surface low is somewhat complicated
as it appears that there is both a Pacific front extending from
the surface low and through the Permian Basin, then a second cold
front (where the stronger thermal gradient lies) to the northwest
along a line from Lincoln, NE to Amarillo, TX to Las Cruces, NM.

As the surface low deepens and tracks east, the Pacific front will
surge east across the Rolling Plains of western North Texas. 
Gusty northwest winds of 20-25 MPH with gusts to around 30 MPH can
be expected behind the front over areas to the west of a 
Gainesville to Fort Worth to Killeen line. This may come close to
advisory criteria, but will wait for some updated high-res
guidance and discuss with neighboring WFOs before committing. At
any rate, the front should make it to about a line from Sherman 
to Corsicana to Killeen line by evening. Ahead of this front, 
widespread rain showers will develop as warm air advection in the 
lower levels of the troposphere strengthens. Given the much drier
air to the west of the Pacific front, it is expected that there 
will be a rather sharp line in both cloud cover and the western 
extent of rain chances with this boundary moving east as the day 
progresses. Some modest instability will be present as well which 
will allow for a few thunderstorms, but severe weather is not 
anticipated. Despite some decently steep mid-level lapse rates, 
with dewpoints barely in the low 50s, not expecting we will get 
MUCAPE much above 150 J/kg or so. Any strong updraft that manages 
to get going could perhaps produce some small hail, but the 
prospects for even that seem low.

By evening, the surface low will begin to occlude over Oklahoma as
the Arctic high continues to build south. This will result in
strong cold air advection overspreading the region by late
Wednesday night, and precipitation chances coming to an end across
the region. Because of the modestly windy conditions (winds will 
diminish to about 10-15 MPH during the overnight period) and some 
residual cloud cover within the deformation zone of the departing 
surface low, most areas should remain above freezing, though lows 
will still drop into the mid 30s for most locations. It should be 
noted that a few of the colder "microclimates" west of Dallas/Fort
Worth could see a light freeze however. Thursday morning will be 
quite chilly however as 10-15 MPH northwest winds persist, 
dropping wind chills into the 20s for much of the region.

Godwin

&&

.LONG TERM... /Issued 235 AM CST Wed Dec 2 2020/
/Thursday Onward/

A rather uneventful period is forecast through the extended with
the region expected to be deprived of any noteworthy moisture.

Beginning on Thursday morning, some patchy drizzle may linger 
across parts of North and East Texas as moisture wraps around the 
back of the departing low. However, this potential is currently low
enough such that none has been included in the worded forecast. 
Temperatures would be several degrees above freezing where any 
drizzle would be occurring, so there are no anticipated issues 
regarding wintry precip. All of the area should be dry by midday 
or so with lingering low stratus over much of the CWA. This will 
keep temperatures on the cool side with highs mainly in the 40s or
low 50s. 

Skies should be clearing out by Friday morning as the upper low
shifts east. This will lead to a mostly sunny and dry weekend as
we remain between upper-level systems. Temperatures will return 
to near or slightly above normal with highs in the 50s/60s and 
lows mostly in the 30s. Surface high pressure will remain anchored
across the southern US, inhibiting any meaningful Gulf moisture 
return through early next week. Another dry cold font should 
arrive either Monday or Tuesday, reinforcing the cool and very dry
airmass already in place. Greater forecast uncertainty exists 
during the second half of the week due to large disparities in 
model depictions of the large-scale pattern. 

-Stalley

&&

.AVIATION... /NEW/
/12Z TAFs/

SHRA have begun to develop east of a KGVT-KCRS-KCLL line, with an
increase in coverage expected through the morning. Confidence is
low in prevailing RA at D10 terminals, though some DZ/BR and 
intermittent -RA does appear likely. This intermittent precip will
likely result in a period of MVFR-IFR CIGs and vsby down to 3SM 
at times. Conditions should improve rapidly this afternoon as 
Pacific front approaches from west, resulting in westerly winds of
around 10 KT. VFR will prevail after 20Z, with conditions looking
to deteriorate once again after 03/12Z as stronger cold front 
moves across the region.

Godwin

&&


.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    54  37  49  33  53 /  60   0   0   0   0 
Waco                60  35  52  32  56 /  30   0   0   0   0 
Paris               46  36  48  34  49 / 100  40   5   5   5 
Denton              54  33  49  29  55 /  50   5   0   0   5 
McKinney            53  36  49  32  53 /  70  10   0   0   5 
Dallas              55  38  50  35  54 /  60   0   0   0   0 
Terrell             53  35  50  33  53 /  80  10   0   5   5 
Corsicana           58  36  52  35  54 /  70   5   5   5   5 
Temple              60  35  52  32  57 /  20   0   0   0   0 
Mineral Wells       52  34  47  29  56 /  10   0   0   0   0 

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$