Area Forecast Discussion
Issued by NWS Dallas/Fort Worth, TX

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FXUS64 KFWD 261944

Area Forecast Discussion
National Weather Service Fort Worth TX
244 PM CDT Mon Jun 26 2017

/Tonight and Tuesday/

Spotty showers, with only an occasional CG strike, are ongoing
across western portions of North and Central Texas, "mostly" west of
I-35. This is where a shortwave will continue tracking slowly
southeast from the Big Country toward the Hill Country and South-
Central Texas through tonight. Will carry scattered convective
chances through nightfall generally southwest of a Graham, to
Mineral Wells, to Waco, to Hearne line where better forcing will be
associated with this shortwave. After nightfall, widely scattered,
mostly showers with isolated thunderstorms should continue south of
I-20 and west of I-35 for the most part. CAPE is relatively "skinny"
through tonight with the tropical airmass in place with weak
northwest 0-6km bulk shear less than 15 knots, so we do not expect
any severe weather, but can`t rule out some strong downbursts
through nightfall from any collapsing activity. Otherwise, it will
remain muggy overnight with light east-southeast winds less than 10

Tropical moisture will continue to remain entrenched across the CWA
on Tuesday. Intensifying lee cyclogenesis will help veer winds
southeasterly to between 10 to 15 mph. Though better forcing from
today`s shortwave will be south of our area, any subsidence behind
this feature looks negligible with weak diffluent flow aloft
continuing overhead. A subtle disturbance will move south across
the region by afternoon and have included low convective chances
areawide. However, richer moisture south of I-20 should allow for
more scattered convection to percolate, with more isolated
coverage further north. Like today, shear will be weak with mainly
insolation and old subtle outflow boundaries playing roles for



/Tuesday night through Monday/

A relatively benign pattern looks to prevail through the middle
and end of the week as North and Central Texas remains situated
within the northeastern periphery of the subtropical high. A
persistent weakness in the upper-level flow across the Gulf Coast
looks to be the only salient feature of interest during this
portion of the forecast. This feature should help push diurnally-
driven convection into our southern and eastern counties each
afternoon. In typical summertime fashion, winds will be
exceptionally light through the troposphere (you`ll have to head
above 200 mb to find winds in excess of 20 kts), and as a result,
any severe threat looks to remain negligible outside of some
gusty winds as storms entrain drier mid-level air. With limited
change to the synoptic pattern through the end of the week,
temperatures look to fluctuate little from day-to-day, with highs
within a degree or two of climatology. Heat index values will
begin climbing towards or just in excess of 100 degrees into the
upcoming weekend.

The longer range guidance remains in decent agreement that a
departing shortwave and associated surface low across the Great
Lakes will send a stalling cold front into Kansas and northern
Oklahoma Friday afternoon and evening. Climatology, and the
progressive nature of the parent upper trough will strongly work
against this front making it south of the Red River. However, deep
moisture underneath the strengthening EML plume (sub-800 mb
mixing ratios in the 15-17 g/kg range) will result in a reservoir
of copious amounts of instability. As a result, it seems at least
plausible that showers and thunderstorms could materialize along
this boundary Friday afternoon and evening, and this is depicted
with reasonable consistency among the global models. The presence
of dry mid-level air and associated DCAPE values in excess of 1000
J/kg would indicate that cold pool amalgamation would be possible
overnight. This would ultimately favor a decaying thunderstorm
complex tracking towards our Red River counties towards daybreak
on Saturday as any activity builds into a weakening low-level
jet. As a result, we`ve bumped PoPs up just a hair along the Red
River to account for southward-sinking activity given the good
model agreement. Weak mid-level winds and increasing capping
across our region should mute the severe weather threat, but we`ll
refine these details over the coming days as the mesoscale
details become clearer.

Looking just beyond our valid forecast period: the deterministic
GFS paints a potentially unsettled pattern for the 4th, but
ensemble guidance offers up a decidedly drier (and hotter)



.AVIATION... /Issued 102 PM CDT Mon Jun 26 2017/
/18Z TAFs/

Isolated-scattered showers continue to percolate across areas
along and west of I-35 this morning, as strong late June heating
works upon rich moisture below 800mb. As a shortwave continues
dropping southeast from the South Plains to over the Hill Country
and Colorado River Valley through the afternoon, best
coverage of showers and a few thunderstorms will be south of I-20
and mainly west of I-35. Brief impacts could occur at all
airports between 20z-01z, but it will be very hit and miss,
Summer activity usually is. VCSH/VCTS will be continued with low
confidence on occurrence at any one terminal, at any one time.
Winds will continue to be light E/ESE less than 10 knots through
the day and into this evening. Some MVFR is expected again by
daybreak at Waco, with DFW airports much less certain as
relatively drier air entraining in from the north in the
925-850mb layer.

VFR cigs will prevail with spotty, diurnal TS/CB this afternoon
into early evening hours. A brief TEMPO window for MVFR above 2
kft will be introduced through 19Z.

Otherwise, light E winds less than 10 knots to prevail with VCTS
from 20z-01z possible. Could be some MVFR BR VSBYs near sunrise
Tuesday, but confidence is too low to introduce at this juncture.

VFR cigs will prevail with spotty, diurnal TS/CB this afternoon
into early evening. Light E/SE winds will prevail less than 10
knots. MVFR cigs look to return for a few hours right after
sunrise Tuesday, but should mix to VFR by 15Z and after.



Dallas-Ft. Worth    72  90  73  92  75 /  10  20   5   5   5
Waco                72  90  72  92  75 /  20  40  10  10   5
Paris               68  89  69  90  73 /   5  10   0   5   5
Denton              68  90  71  91  74 /  10  20   5   5   5
McKinney            68  90  71  91  74 /  10  20   5   5   5
Dallas              73  90  74  92  76 /  10  20   5   5   5
Terrell             70  90  71  91  74 /  10  20   5  10   5
Corsicana           72  89  72  91  74 /  10  30   5  10   5
Temple              71  88  70  90  73 /  20  40  10  10   5
Mineral Wells       69  89  70  92  72 /  20  20   5   5   5




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