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

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FXUS64 KFWD 190507 AAB

Area Forecast Discussion...UPDATED
National Weather Service Fort Worth TX
1207 AM CDT Sun Aug 19 2018

/06Z TAFs/

We are in a bit of a lull right now with regards to precipitation,
but storms in NE Texas may continue to impact Bonham arrivals for
another hour. Our attention now turns to the west where a complex
of storms is moving across the Texas Panhandle, and additional
storms are developing ahead of it. Model guidance is in pretty
good agreement the majority of this activity will remain north of
the DFW area tonight, but there is still a chance for showers or
isolated storms closer to daybreak. I cannot completely rule out a
few showers around the DFW Metroplex between 06-12Z, but I did
not want to carry 10 hours of VCSH. We will watch the trends
overnight and adjust if a more prevalent threat for convection may
impact the Metroplex before 12Z. The best rain chances in the
morning hours appear to be between 12-16Z when the southern edge
of the complex moves across the area, and have maintained VCSH.
After a few hours break, additional convection is possible in the
afternoon and evening hours and have included a VCTS from 22-01Z.
Gusty winds, lightning, heavy rainfall and possibly small hail
will again be possible. Unfortunately, rain chances do not end
there as there is another chance for showers or storms overnight
Sunday into Monday as a front approaches the area. South winds
will prevail for much of the period but wind shifts are possible
due to convection. VFR cigs are expected through the period with
high- based convection around 7-9 kft.

For Waco, benign, VFR conditions are expected with south winds
generally 9-13 kts. Rain chances increase for Waco just beyond the
valid TAF period.



.SHORT TERM... /Issued 331 PM CDT Sat Aug 18 2018/
/Rest of Today and Tonight/

Towering cumulus is bubbling this afternoon in a region of
enhanced surface convergence across our northwestern counties.
Regional mesoanalysis reveals the airmass is just about uncapped,
and we`re beginning to see some convective attempts across some of
our northwestern counties. There is also some enhancement to the
large scale forcing from a subtle shortwave rippling across
western Oklahoma. This lifting mechanism, in concert with robust
diurnally-driven vertical PBL circulations should be sufficient to
spark isolated to scattered convection, mostly west of I-35 and
north of I-20 through the afternoon. Deposited outflows may allow
activity to develop into the Metroplex as time goes on, but the
greatest coverage appears to be focused just to the west. A
localized strong-severe downburst threat exists in this hot and
unstable environment in addition to locally heavy rainfall with
very slow storm motions. PoPs taper quickly downwards south of
I-20 where instability drops off.

This activity will begin to diminish after 7-8 PM with the loss of
daytime heating. Additional showers and a few storms may develop
late this evening and overnight across parts of North Texas in
response to a strengthening low-level jet. Moisture drops off
pretty quickly with southward extent, so PoPs tonight will remain
relegated to areas north of I-20. We`ll also be watching a
potential MCS dropping out of the Texas Panhandle and into the
Rolling Plains late this evening in association with the next
shortwave--presently moving through Colorado. Veering 925-850 mb
flow and northward-retreating instability doesn`t seem to support
MCS maintenance into our CWA, but we`ll paint some 20-30% PoPs
across our northwest to account for any elevated activity that
develops as the LLJ overtops the exhausted outflow. This outflow
could also deliver a gusty wind threat to our northwestern locales
very late tonight.



.LONG TERM... /Issued 331 PM CDT Sat Aug 18 2018/
/Sunday through Saturday/

A strong shortwave trough will be moving through the Central
Plains early Sunday morning with a cluster of convection ongoing
across parts of northwest Texas and Oklahoma associated with very
strong low level warm advection. This area of stronger forcing for
ascent will quickly spread northeast through the early morning
hours with the best precipitation chances remaining across
Oklahoma. We`ll likely have some trailing showers and
thunderstorms across our far northern counties though so we`ll
keep PoPs at 20-30% mainly north of I-20.

As we get into the early afternoon hours, a secondary area of
ascent will begin to rotate around the main upper trough and
should begin to spread into North Texas. This will allow the main
cold front to the north to begin to spread southward into the
region by evening. Most of North Texas will remain dry on Sunday
after any morning convection, but strong heating again during the
afternoon hours should lead to at least some scattered showers and
thunderstorms. Again, these should generally be along and north of
I-20 with the best chances closer to the Red River. High
temperatures will climb back into the upper 90s in most locations
with readings near 100 degrees south of I-20. Any storms that
develop Sunday afternoon will have a localized downburst wind

By Sunday night, the cold front will be spreading through North
Texas and should still continue to have some scattered showers and
thunderstorms along it. It`s a little uncertain whether or not any
afternoon convection will disrupt convective potential along the
front, but several high resolution models do suggest that this is
possible. The timing of the front coincident with increasing
nocturnal inhibition may mean that many areas miss out rainfall
with this frontal passage. Either way, we`ll have fairly high
PoPs (40-60%) across our north and northeast counties Sunday
evening and night with rain chances spreading south through the
overnight hours.

Slightly cooler air will build into the region on Monday behind
the front with only low lingering storm chances across our far
southeast counties. Things should remain dry through mid week with
temperatures slightly below normal. The GFS remains bullish on
keeping the upper ridge to the west on Thursday and Friday with an
active northwest flow pattern and several chances for rain. The
ECMWF has much stronger ridging over the southern Plains and
little chance for rain. For now, will side a little more
conservative and keep the forecast dry through the end of next
week and reassess as we get a little closer.



Dallas-Ft. Worth    74  97  78  93  73 /  50  20  40  10   5
Waco                78 101  78  96  74 /  10   5  30  20  20
Paris               76  93  74  90  69 /  30  30  60  20  10
Denton              74  96  75  92  69 /  40  30  40  10   5
McKinney            72  96  76  92  70 /  50  30  40  10   5
Dallas              74  97  78  94  74 /  50  20  40  10  10
Terrell             77  97  77  93  71 /  40  20  40  20  10
Corsicana           77  98  77  95  73 /  10  10  30  20  20
Temple              75  99  77  97  74 /   5   5  20  20  20
Mineral Wells       74  96  73  93  69 /  40  20  40  10   5




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