570 
FXUS64 KFWD 191251
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
751 AM CDT Sat Oct 19 2019


.UPDATE...

The vigorous shortwave that gave parts of the area some widely
scattered, brief, elevated showers and storms this morning is 
quickly exiting the area. Meanwhile, a cold front continues to 
enter the far western CWA as of sunrise. 

I am removing the slight chances for storms in the far eastern 
counties and adding some patchy-areas of fog across our far 
southeast counties. South winds 5-10 mph winds in advance of the 
cold front has helped to advect rich low level surface dew points 
temperatures in the upper 50s to lower 60s across this area with 
stratus and some fog. Though isolated areas of dense fog are 
possible, I don't believe it will be widespread enough for any 
advisories this morning. This fog should be short-lived and begin 
dissipating readily after mid-morning, as strong insolation heats 
up surface temperatures rapidly. 

05/

&&


.AVIATION... /Issued 655 AM CDT Sat Oct 19 2019/
/12z TAFs/

Concerns and challenges: FROPA 15z-18z will shift south winds
around 10 mph to the west, then northwest 10-15 knots by 18z.
Otherwise, VFR with no precipitation expected. 

A vigorous mid level impulse continues moving east of the airports
this morning with just scattered mid-high level clouds in it's
wake. Eventually, SKC conditions will prevail as a cold front
arrives later this morning...putting DFW and DAL into north flow.
Waco will likely see the wind shift a few hours later; or between
18z-21z. 

NW winds 10-15 mph behind the cold front later today are expected
to become light N or calm after sunset tonight, as the dry boundary
layer decouples rapidly and high pressure at the surface slides
into the area. 

05/

&&

.SHORT TERM... /Issued 350 AM CDT Sat Oct 19 2019/
/Today Through Tonight/

A vigorous mid level impulse is moving east across the CWA early
this pre-dawn, Saturday morning. Low level southerly flow on area
VWPs from local radars was impressive and currently southerly at 
40-45 knots, which shows the influence this strong shortwave is 
having even on the dry, lower levels. GOES satellite imagery was
even indicating a gravity wave shooting out well in advance of the
elevated convection across Central Texas. Widely scattered, high-
based and elevated showers and tstorms continue racing east across
mostly the area from I-35 and to the east, where strong vertical 
motions are saturating and destabilizing the mid levels quite 
impressively considering the initial dry environment this system 
arrived into. Central Texas areas are a bit more displaced south, 
but isolated storms were occurring as far south as Cleburne and 
Italy in Johnson/Ellis counties per latest regional radar. I can't
rule out isolated, short-lived elevated convection through mid- 
morning across the far eastern counties per the real-time data. In
addition, pooling of relatively higher dew points > 60 degrees 
across parts of Milam, Robertson, and Leon counties may result in 
brief fog development from the Highway 6 corridor east toward I-45
around sunrise. I do not expect any impacts from any fog 
development with fog dissipating quickly by mid morning in 
response to rapidly warming temperatures and increasing surface 
wind speeds. 

Beyond mid-morning and in wake of this morning's shortwave 
disturbance exiting the area, we should see the cold front sweep 
readily southeast through the area through this afternoon. This 
front will mainly drawn in slightly drier air into the region 
with any thermal advection being negligible. Plentiful sunshine
will prevail with highs warming into the upper 70s northwest to 
near 90 degrees across parts of Central Texas. It will be breezy 
from the I-35 corridor and points west where northwest winds 10 
to 15 mph will contain occasional gusts to around 20 mph as
momentum transfer with the boundary layer is easily achieved. A 
mostly clear and seasonably cool night is expected for your
Saturday night as surface high pressure settles across the area. 
A good radiational cooling set up will occur as wind speeds come 
down quickly after sunset with decoupling of the dry boundary 
layer. Lows by Sunday morning are expected to be mostly in the 50s
with near calm winds to start a day that will become much more
active later on.

05/

&&

.LONG TERM... /Issued 350 AM CDT Sat Oct 19 2019/
/Sunday through Friday/ 
The cold front will stall out across South Central and Southeast 
Texas Sunday morning but as a longwave trough deepens over the 
Central part of the country, southerly flow will intensify over 
the region. The southerly flow and sunshine will certainly result 
in very warm temperatures as highs will reach the low 90s in the 
west to the mid 80s in the east. Elevated grass fire danger will 
occur across the western zones as RH drops to near 25% and surface
winds increase to 10 to 20 mph. 

Moisture pooled on the south side of the front will return 
northward during the day but the primary forecast uncertainty is 
how much, how fast, and how deep will the moisture layer be by the
early evening hours when synoptic forcing for ascent begins to
impinge upon the region. The moisture quality will control 
whether the atmosphere can convect while temperatures are still 
warm enough from daytime heating to support surface based 
convection and a more substantial severe weather risk. This 
moisture layer looks to be very shallow west of I-35, but have 
more depth east of I-35. At this time most of the guidance does 
not show the moisture arriving fast enough for storms anywhere in 
the CWA Sunday evening, but a couple of the CAMs and the ECMWF do 
show it making it into the northeast zones where it juxtaposes 
with forcing for a risk of supercells and severe weather. Should
this occur, all modes of severe weather would be possible with 
this activity between 6 pm and 10 pm Sunday evening mainly across
the northeast zones. SPC has outlooked a part of the CWA in 
slight risk, but given the uncertain and highly conditional nature
of this threat, that forecast may be a bit aggressive.

With the loss of daytime heating temperatures will cool after
sunset and CINH will increase over the entire area. However
increasing forcing for ascent will attempt to remove the capping 
inversion and it is likely that once a cold front begins to plow 
into the CWA around midnight that we will see a line of storms
develop along it. The line may initially be broken across the NW
zones, but should fill in as it reaches the DFW Metroplex around 2
am. Have increased PoPs into the likely and categorical range for
the entire CWA except for the NW zones. While deep layer shear 
and instability values are both squarely in the severe weather 
parameter space, the mode of the convection (a line parallel to 
the shear vector) should mitigate the severe weather threat. 
Still, some marginally severe hail or wind may occur with this 
line as it progresses through the CWA. Rainfall will average 1/10
of an inch in the northwest to over 1 inch in the east. 

Drier northwesterly winds on Monday will bring some cooler air
into the region with highs topping out in the 70s in what should
be a pretty nice day after any lingering morning rain/clouds exit
to the southeast. Excellent radiational cooling is expected Monday
night and temps will drop into the 40s for most locations. 
Gradually warming temperatures will occur Tuesday and Wednesday 
with pleasant weather prevailing in dry northwesterly flow aloft. 

The next system will noticeably impact our sensible weather on
Thursday as a longwave trough amplifies and deepens over the 
Central US. There is a bit of uncertainty on whether this system 
will be progressive (ECMWF) or slower with a closed low at the 
base of it (GFS/GEFS). Either way it looks like a front will 
arrive on Thursday afternoon with a chance of showers and storms. 
Either the trough will be progressive and send colder air in here 
faster, or be slower and result in overrunning clouds/rain
continuing into Friday. Both scenarios warrant lowering high 
temperatures Friday with temps possibly struggling to reach 60.
Fear not, another pleasant Autumn weekend should follow. 


TR.92

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    83  55  88  56  74 /   0   0  10  80  10 
Waco                88  56  90  58  76 /   0   0  10  80  20 
Paris               80  55  80  57  71 /   5   0  10  90  20 
Denton              81  53  87  53  74 /   0   0  10  60  10 
McKinney            82  54  86  56  73 /   0   0  10  80  10 
Dallas              84  58  88  57  74 /   0   0  10  80  10 
Terrell             84  55  88  59  74 /   0   0  10  90  20 
Corsicana           86  57  86  59  73 /   5   0  20  90  30 
Temple              88  58  89  59  76 /   0   0  20  70  30 
Mineral Wells       81  52  89  53  74 /   0   0  10  50   5 

&&

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

$$

05/92