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FXUS64 KFWD 231434 AAA

Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
934 AM CDT Fri Aug 23 2019

The southern edge of a backbuilding storm cluster crossed the Red
River about an hour ago and continues to move slowly east. POPs
along the Red River have hence been increased to reflect RADAR 
trends. Outflow from the ongoing convection should become the 
focus for additional development as the atmosphere destabilizes 
this afternoon. Chance to slight chance POPs have been expanded 
southward as it appears that one or more of these outflow 
boundaries will push south of the I-20 corridor by late 
afternoon. The severe threat still appears to be low, but any 
storm which occurs during peak heating hours will have the 
potential to produce gusty winds. Seasonably hot and humid 
conditions can otherwise be expected outside of precipitation



.AVIATION... /Issued 641 AM CDT Fri Aug 23 2019/
/12Z TAFS/

The main concern through this TAF cycle will be the potential for
thunderstorms around the Metroplex this afternoon and again on
Saturday. A weak frontal boundary is near the Red River this
morning and will slowly sag south through the day. Thunderstorms
are already ongoing across southern Oklahoma and may continue to
impact northbound arrivals/departs for the next few hours.
Scattered thunderstorms are expected to develop along the
southward moving boundary early this afternoon. We have a VCTS in
for the Metroplex TAF sites at 20Z with thunderstorm activity
continuing into the early evening hours.

Thunderstorm coverage should diminish this evening with the loss 
of daytime heating. Additional scattered thunderstorms are
expected again on Saturday, just beyond the current TAF period.

At Waco, most thunderstorm activity should be both to the north
and to the south of the airport. We'll have to watch the inland
push of sea breeze convection this afternoon, but most activity
should remain to the southeast. Outside of thunderstorms, VFR
should prevail.



.SHORT TERM... /Issued 316 AM CDT Fri Aug 23 2019/
/Today and Tonight/

Early morning objective surface analysis shows a broad area of
convergence across southern Oklahoma, likely the result of an
outflow boundary from earlier convection. This, combined with a
respectable 20-25 kt south wind above the surface, has resulted 
in a reinvigoration of showers and thunderstorms across Oklahoma 
during the overnight. Given the slightly weakened state of the 
upper ridging across North Texas, we'll have to watch for a 
southward shift in the low level convergence through the day today
along with additional southward moving outflow boundaries. 

Summertime convective forecasts in weak flow regimes are
especially difficult with respect to location, but we think the
most favored area for thunderstorms today will generally be north
of I-20 with areas along the Red River and northwest of the
Metroplex having the best chance. This is where low level
convergence is expected to be maximized as southward moving
outflow spreads into the region. Given the absence of any capping,
towering cumulus should be able to develop into thunderstorms in 
a few locations. 

The atmosphere across North Texas will be modestly unstable later
this morning and afternoon featuring a deep warm moist layer to 
400 mb (PWs ~2"), paltry deep layer winds (0-6km shear ~15 kt),
and boundary layer mixed to around 750 mb. This environment will
generally be supportive of non-severe, poorly organized slow
moving convection, capable of producing very heavy rainfall over
short periods of time. The strongest storms could produce a severe
downburst wind gust given the decent precip loading potential and
fairly well mixed boundary layer. Widespread severe weather is not

We'll have highest PoPs this afternoon (~30-40%) northwest of the
Metroplex with additional low PoPs across our far southeast
counties to account for an uptick in sea breeze convection
spreading inland. Some of this activity in the northwest may
linger into the evening hours, so we'll hang on to some low PoPs
into early tonight. High temperatures may be tempered some by an
increase in clouds, so we should see slightly cooler readings
across our northern counties this afternoon, but it'll still be
plenty warm. We'll have highs in the low/mid 90s north of the
Metroplex with upper 90s elsewhere. Other than the lingering low
storm chances across the north tonight, it should be mostly quiet
with lows in the mid/upper 70s areawide.



.LONG TERM... /Issued 316 AM CDT Fri Aug 23 2019/
/This Weekend Through Next Thursday/

The dampened and flat upper ridge present to end of the week will
continue to break down in response to an impressive mid level
impulse tracking across Kansas/Oklahoma/and North Texas on
Saturday. Sans uncertainty regarding any mesoscale storm outflow
boundaries left over from today's activity, no significant
synoptic surface fronts will be present across the area. Despite
weak mid level flow overhead, our environment will be characterized
by very warm temperatures in the 90s, rich moisture with PWATs 
1.75-2 inches, and high instability. Through midday, the main 
focus for isolated-scattered thunderstorms will be mainly along 
and north of I-20 in closer vicinity of better large-scale ascent 
associated with the mid level shortwave tracking eastward across 
Oklahoma into Arkansas. As diurnal heating cranks up and instability
increases, we'll see better chances across our northern and eastern
counties with more isolated chances across the majority of Central

Outside of the immediate Red River Valley where highs in the 
upper 80s- lower 90s are advertised in an area of more expansive 
cloud cover; the rest of the CWA should see highs still surge into
the mid to to upper 90s. We could see a few stronger storms in 
the afternoon and evening Saturday hot temperatures this time of 
year resulting in higher values of DCAPE and high cloud bases.
Thus gusty downburst winds will likely occur with stronger storms.
Mid level lapse rates on the order of 6-6.5 deg C/km and modified
pockets of drier air aloft should allow for some deeper updrafts 
and even the possibility of hail with the strongest of activity. 
Lastly, slow steering currents and/or storm mergers with the moist
environment in place will also present the potential for pockets 
of heavier rainfall and the possibility of minor flooding...mainly
areas north of I-20 and east of I-35. 

Mid level heights will briefly rise Saturday night in wake of our
departing impulse moving through the Ozarks to the northeast of 
the area. I have lingered slight chances mainly east of I-35 and 
along the immediate Red River Valley for any lingering ascent
Saturday evening. However, another mid level impulse will be 
right on the heels of the first one Saturday night, but is being 
advertised to track southeast across Northeast Oklahoma/Southeast 
Kansas -- before heading into the Ozarks on Sunday. GFS wants to 
develop an MCS and associated cold pool much further south across
Eastern Oklahoma versus it's NAM counterpart which would obviously
have drastic differences on convective chances across especially 
our northeast CWA late Saturday night into Sunday. I have decided 
to take a mean of these solutions for now and keep the better 
chances just north through east of the immediate DFW area on 
Sunday. With our area being grazed by this mid level impulse and 
warmer 850 temperatures across the west, I will lean toward warmer
guidance on high temperatures Sunday pushing the century mark 
along and west of I-35, with lower-mid 90s more the rule across 
East Texas. Again with the hot temperatures in place, the possibility
of strong to even marginally severe storms with downburst winds, 
frequent lightning, and heavy rainfall will be a possible during 
especially the afternoon and evening hours. 

The heat returns with a vengeance for the early half of the week,
as a strong mid level anticyclone to our west re-establishes
eastward and over North and Central Texas. In addition, a mid
level impulse tracking east across the Oklahoma/Kansas border will
help to draw a cold front southward across the Panhandle and 
Central Oklahoma which will likely result in veering low level 
flow just above the surface out in advance. Outside of highs in 
the mid- upper 90s across our East Texas counties, the remainder 
of the CWA should easily see high temperatures range between 
100-103 degrees with heat indices between 105-110 degrees across a
vast part of the area on Monday afternoon. It's going to be 
steamy and models have been consistent on this trend for the past 
several be ready. 

Consensus of medium range models bring this cold front across the
Red River, but begin to slow it down or even stall it north of 
I-20/30. This feature will provide a focus for a few showers and
thunderstorms and combined with continued hot temperatures Tuesday,
there will be an increasing threat for strong storms -- particularly
across our far northern tier counties near the surface front and 
better large-scale ascent with the mid level impulse. Further 
south and west, hot high temperatures around the century mark will
continue on Tuesday. Similar convective chances will continue 
into mid week with slightly cooler temperatures occurring near the
immediate Red River Valley, but increased cloud cover should 
allow high temperatures to settle well back down into the 90s. 
Otherwise, a flat mid level ridge will slowly re- establish toward
the end of the week, but not be overly intense. Seasonably hot 
temperatures with diurnal, isolated convective chances each day 
can be expected. With long-range model blends being notoriously 
too cool due to trends toward climatology, I did trend toward 
warmer guidance of the European model during this time frame. 



Dallas-Ft. Worth    97  78  94  78  98 /  40  20  30  20  20 
Waco               100  76  97  78 100 /  20   5  20  10  10 
Paris               93  73  88  73  90 /  40  20  40  20  40 
Denton              95  76  93  77  96 /  40  20  30  20  20 
McKinney            96  75  92  76  95 /  40  20  30  20  30 
Dallas              97  79  95  79  98 /  30  20  30  20  20 
Terrell             97  75  95  76  97 /  20  10  30  20  30 
Corsicana           98  75  94  76  96 /  20   5  30  20  20 
Temple              98  76  96  77  99 /  20   5  20  10  10 
Mineral Wells       97  74  94  74  98 /  40  20  30  10  10 



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