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Area Forecast Discussion (AFD)

Issued by Fort Worth/Dallas, TX (FWD)

                            
000
FXUS64 KFWD 190502
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
1202 AM CDT Wed Jun 19 2019

.AVIATION...
/06Z TAFs/

Turbulent zonal flow will maintain periodic thunderstorm chances.
Aided by an impulse embedded in this flow, convection proliferated
along a West Texas dryline, then made steady progress east during
the evening. The westerly upper flow and advancing outflows will 
maintain this forward motion during the early morning hours.
Although the activity in western portions of North Texas are
outflow-dominant and the available instability will steadily
diminish as these convective elements attempt to approach the I-35
corridor. While this activity may reach the Metroplex TAF sites, 
a decline in intensity is expected, and any remaining
thunderstorms would impact the Metroplex during the nocturnal
minimum for airport operations.

A brief wind shift to the northwest may occur, but the convective
activity early this morning is unlikely to have any lasting 
impact on the winds. A more significant player for our
thunderstorm potential Wednesday afternoon/evening will be an 
approaching cold front. While the convective activity along the 
boundary may affect the I-35 corridor late in the day, a permanent
wind shift is unlikely.

25

&&

.SHORT TERM... /Issued 334 PM CDT Tue Jun 18 2019/
Difficult forecast tonight into tomorrow morning related to
convection...both in timing and location. The GFS tends to be the
most bullish in developing storms out in W TX this evening and
maintaining them somewhat as they move towards the Metroplex 
around midnight tonight. Several of the meso models hint at the 
same scenario, but differ widely on location and timing...as well 
as intensity of what's able to make it's way towards the I-35 
corridor. Nonetheless, the best potential for any severe storms, 
which would mainly be a damaging wind and hail threat, will remain
over our NW counties late this evening. As the remaining storms 
approach the metroplex and in areas along and south of I-20, they 
should be dissipating due to more stable air in place. 

The other factor for early Wednesday morning that we'll have to
keep an eye on is the complex expected to develop over OK later 
tonight. As these storms shift east and slowly southward, we could
see a few remaining storms make their way into the Red River 
Valley, generally east of Sherman, early tomorrow morning. Don't 
think we'll have to worry about any severe weather with these in 
the early morning, but will definitely be a key factor for storms 
the rest of the day.

&&

.LONG TERM... /Issued 334 PM CDT Tue Jun 18 2019/
/Wednesday and beyond/

Summary: Unsettled weather will continue in the long term
forecast. There will be a risk for severe weather Wednesday 
afternoon and evening, and there remains uncertainty on the
location of thunderstorm development. A day of rain-free weather 
is expected on Thursday and most of Friday, but low storm chances
will return this weekend and early next week. Heat will also be a
concern on Wednesday and Thursday.

There may be a few lingering showers and isolated storms across
parts of the region Wednesday morning, but an overall downward
trend is expected through mid morning. Across the Central Plains,
another cluster of thunderstorms associated with a shortwave will
continue to track southeastward. This will send a weak cold 
front/outflow boundary south towards North Texas during the day, 
and will be an area of focus for thunderstorm development 
Wednesday afternoon and evening. As the boundary approaches during
the day, warm and humid conditions are expected across the 
region. Afternoon temperatures will be in the 90s and dewpoints 
will approach the low to mid 70s. Heat index values across the
region may be near or above the century mark. Decided to hold off
on issuing a Heat Advisory for several reasons: (1) possible cloud
cover from overnight convection, (2) how far south the boundary 
tracks, and (3) if thunderstorms develop earlier, cloud cover may 
keep high temperatures below the forecast.

In regards to the severe weather potential for Wednesday 
afternoon and evening, there remains uncertainty on exactly where
thunderstorms will initially develop. This will be highly 
dependent on the overnight convection and the location of the 
southward moving boundary. While most guidance keeps the boundary
across North Texas, mainly near the DFW Metroplex and areas
northeast, overnight convection may push the initiating boundary 
further south towards Central Texas. Regardless, the environment 
across North and Central Texas will be favorable for severe 
weather, with surface based CAPE upwards of 3500 J/kg, little to 
no CIN, EBWD values upwards of 30-40 knots, and steep mid level 
lapse rates upwards of 7.5 C/km. This would support a discrete 
supercellular mode along the boundary initially, with all modes of
severe weather possible. Modest mid level flow and dry air 
entrainment would support a strong cold pool/outflow boundary from
these cells, which could support additional thunderstorm 
development. There is a possibility the discrete cells may 
organize into a cluster of thunderstorms, and this would result in
primarily a damaging wind and large hail threat. Given the 
uncertainty, all of North and Central Texas should stay weather 
aware and be prepared.

Thursday will feature rain-free, hot, and humid conditions across
the region, and areas mainly west of I-35 may approach the 
century mark. Heat index values may reach Heat Advisory criteria,
and we'll continue to monitor whether an advisory is necessary.
Dryline convection across the west may approach the far western 
counties Friday afternoon/evening, and continued a mention of low 
PoPs to account for this. Unsettled weather is expected through 
the weekend as a few disturbances track eastward. Most of the 
scattered activity is expected to be diurnally driven through the 
weekend. There will be better storm chances on Sunday as a 
shortwave moves across the Central Plains. We'll continue to 
monitor in the coming days.

Garcia

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    75  95  75  97  77 /  40  30  30   5  10 
Waco                75  95  77  99  77 /  20  20  20   5   5 
Paris               71  87  71  91  75 /  40  50  50   5  10 
Denton              73  94  72  97  76 /  40  20  30   5  10 
McKinney            74  93  73  95  76 /  40  30  40   5  10 
Dallas              76  96  75  97  77 /  40  30  30   5  10 
Terrell             74  93  75  97  76 /  30  40  40   5  10 
Corsicana           74  93  75  95  75 /  20  20  30   5   5 
Temple              74  96  77  98  76 /  10  20  10   0   5 
Mineral Wells       70  95  71  99  74 /  40  20  20   5  10 

&&

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

$$

25/30