608 
FXUS64 KFWD 130435
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
1135 PM CDT Fri Apr 12 2019


.AVIATION...
/06z TAFs/

Concerns and challenges: Timing the arrival of both showers and
some strong to possible severe storms between 06z-18z Saturday,
and MVFR-IFR cigs, with gradual lifting Saturday night with very
gusty NW winds in wake of our cold front and dynamic surface low 
pressure system to the east.

Little change outside of some minor timing tweaks to the previous
00z TAFs. Spotty warm advection driven storms should remain mainly
east of the airports through 09z, though can't rule out an
isolated TS between now and then. For now with low confidence, I
will maintain NE winds near 10 knots with low VFR cigs and VCSH at
all DFW airports, but have prevailing MVFR cigs at Waco from here
on out. Best window for TSRA looks to remain in the 11z-17z
window, but have chose 13z-16z and my most favored time at all
airports considering timing of a broken line of strong to severe
storms associated with the greatest large-scale ascent. Only
high-based or even elevated scattered showers and isolated TS
possible across DFW airports only, as the cold core of the mid
level low lifts across the region Saturday night. 

Otherwise, winds will be very challenging with even a brief
potential for strong crosswinds at DFW late Saturday afternoon and
evening. NE winds will back N 15-20 knots by midday, then become
NW 20-30 knots and gusty by 00z Sunday and beyond. A few gusts
over 35 knots definitely not out of the question. At Waco, winds 
will be shifting more in a veering fashion being being close to 
or right where the surface low tracks NE during the day. E-NE 
winds around 10 knots will veer SW 15-20 knots just before 18z 
Saturday, before veering W-NW 15-25 knots late in the afternoon 
and early evening Saturday. 

05/

&&


.SHORT TERM... /Issued 344 PM CDT Fri Apr 12 2019/
/Tonight into Tomorrow/

Primary concern in the short-term is the potential for severe
weather and heavy rainfall across North and Central Texas. While
some uncertainty remains regarding severe potential (Question:
Does uncertainty ever truly go away in this business? Answer: 
No.), synoptic details and timing/distribution of heavier
precipitation continues to be refined.

In the meantime, a rather pleasant (if not slightly cool) 
afternoon will transition into a cool, dry April evening. High 
clouds will spread across our area from the west, in association 
with southwest flow ahead of a deepening mid/upper trough. On the 
western periphery of this system, a 140-kt upper-level jet streak
will dive southward through this evening, amplifying the system 
over northern Mexico. 925-850mb southerly flow ahead of the trough 
will intensify in response, and showers and thunderstorms are 
forecast to blossom across much of the region. One convective
corridor will likely exist near/east of the I-35 corridor after 
midnight. In this zone, a focused channel of isentropic ascent 
will likely support shallow convective streamers feeding northward
to a band of thunderstorms extending from North Central Texas 
east to the Arklatex. A few of these storms will likely be capable
of at least marginally severe hail.

Meanwhile, strong ascent on the nose of the approaching mid/upper
trough will work in tandem with southeasterly surface flow over
the Hill Country/Concho Valley to ignite strong/severe convection
to our west/southwest overnight. These cells will likely approach
our southwestern counties towards daybreak. Increasingly 
meridional flow aloft may support an evolution towards a squall 
line, which would enhance the damaging-wind threat where 
sufficient surface-based destabilization occurs. This will be
dictated by the northward advance of richer surface theta-e
tonight into tomorrow morning. Tied to this advance, an 
organizing low is expected to track from parts of Central Texas to
East Texas through mid-day, and the warm sector east/southeast of
this low should be sufficiently unstable to support at least some
damaging-wind potential in any bowing segments. The most likely
area for such potential appears to remain along/southeast of a
Temple-to-Athens line. Of note, slightly elevated convection just
north of the front may still be able to produce damaging gusts if
cells can sufficiently organize and overcome weak static stability
associated with the frontal surface aloft.

As for the tornado potential, this still appears rather nebulous
across our southeastern counties. Cells feeding into the
aforementioned line/cluster of storms will be within a moist
environment characterized by favorable low-level shear. Questions
remain regarding the ability of adequately unstable surface air to
race back northward ahead of the line tomorrow morning. If dew
points in the upper 60s can stream ahead of the surface cyclone,
stronger low-level mesocyclones may be attainable. However, the
possibility of widespread morning precipitation also casts doubt
on just how unstable the warm sector will be. With that said, any
tornado potential would likely be maximized across our far
southeast, generally from Cameron to Palestine during the
morning/mid-day hours.

Heavy rain and some minor flooding could occur across essentially
all of the county warning area as cells move east through the 
morning. The most likely area will be across East Texas, where a 
combination of initial warm-advection storms and then the primary 
convective band will focus higher rainfall amounts. The 
progressive nature of the system should preclude widespread flash 
flooding issues, but at least localized flash flooding will be 
possible.

The worst of the storms moves east into the Sabine Valley by mid
afternoon. Conditions will dry considerably behind the surface
cyclone, but robust ascent and steep lapse rates associated with 
the primary wave may yield isolated stronger storms (capable of 
hail and gusty winds) during the afternoon and early evening. 
Convective overturning casts doubt on this scenario, but 
satellite/radar trends will need to be monitored even after the 
initial wave of convection passes.

Conditions then turn cooler as northwesterly winds and cold
advection increase tomorrow evening.

Picca

&&

.LONG TERM... /Issued 344 PM CDT Fri Apr 12 2019/
/Saturday Night Onward/

The strong vertically stacked storm system will continue moving 
across North and Central Texas early Sunday morning, leaving 
behind a few lingering showers and storms associated with a band 
of frontogenetical forcing on the northwestern edge of the system.
As is the case with cold core systems, lapse rates will be steep 
enough to warrant a mention of at least some isolated lingering 
thunderstorms as the system departs to the east. Numerical 
guidance is attempting to tease North Texans with one last taste 
of winter as cold air filters in behind the system while light 
precipitation is falling. It is possible that a few locations in 
the far northwestern counties may see a few snow flakes flying 
around prior to sunrise Sunday, but with surface temperatures 
remaining in the mid to upper 30s and the antecedent surface 
conditions due to the increasing sun angle, there is no threat for
wintry precipitation impacts. Once again, the probability of this
occurring is low but given the cold thermodynamic profile, it is 
a possibility.

A drying trend will begin Sunday as the dynamic upper low moves 
away from North and Central Texas and upper level ridging moves 
in. High temperatures will be highly dependent on just how much 
cloud cover will linger across the region. At this point, clouds 
will likely clear from west to east through the I-35 corridor, 
allowing for upper 60s west of I-35 and lower 60s to the east. 
Surface ridging will continue shifting to the east and surface 
winds will quickly turn southerly by late Sunday night, keeping 
lows in the 40s to around 50 degrees. 

By Monday, dry conditions will continue with temperatures 
increasing between 10-15 degrees compared to Sunday. Locations 
west of I-35 can expect to climb into the low to upper 80s, while 
those east of I-35 will remain in the mid to upper 70s. The 
tranquil weather will bleed into Tuesday. This time, increasing 
cloud cover will prevent high temperatures from reaching 80 
degrees. 

Another potent storm system will be digging its way south across 
the Rockies Tuesday into Wednesday and likely yield to the 
development of a dryline across West Texas Wednesday afternoon. 
There still remains some uncertainty as to the timing of the 
system, therefore, confidence in the forecast for the mid week 
system remains low. For now, it appears as if sufficiently high 
instability along with the presence of 40-45 kts of 0-6 km shear 
will increase the potential for severe weather. Exact hazards and 
timing is unknown at this time but this system bears watching as 
we proceed through the weekend. Any lingering showers and storms 
will likely be moving east of North and Central Texas by Wednesday
night as a cold front helps push all moisture east of the region.
The cold front will help keep temperatures in the upper 60s to 
lower 70s both Thursday and Friday, with dry conditions continuing
into next weekend.


Hernandez

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    55  59  43  67  50 /  70 100  40   0   0 
Waco                59  67  44  68  49 /  70 100  10   0   0 
Paris               53  59  42  62  44 /  90 100  60   0   0 
Denton              53  57  40  65  48 /  80 100  50   0   0 
McKinney            53  59  42  64  47 /  80 100  50   0   0 
Dallas              56  61  45  67  50 /  70 100  40   0   0 
Terrell             57  64  43  65  46 /  70 100  30   0   0 
Corsicana           60  68  44  66  47 /  70  90  20   0   0 
Temple              62  71  44  69  49 /  60 100   5   0   0 
Mineral Wells       52  57  39  67  47 /  80 100  40   0   0 

&&

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

$$

05