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

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KFWD 200932
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
432 AM CDT SAT AUG 20 2016

.SYNOPSIS...
Widespread heavy rain is expected again across a good portion of
North TX today and tonight. Additional heavy rain will be possible
again on Sunday and Sunday evening. There may be a brief respite
from the precipitation late Tuesday into early Wednesday, but rain
chances are forecast nearly every day next week.


&&

.SHORT TERM (Today through Monday)...
The main challenge this morning will be the cessation of the
loosely-defined convective complex across western North TX and
southwest OK. AMDAR, WSR-88D VWP, and RAP model output suggest
that low level south-southwest flow at around 25-35 knots will
continue to overspread a good portion of North TX this morning.
With GPS and satellite-derived PWAT values in excess of 2" across
the area, I feel that there is a good bet for at least some brief heavy
rain with a fair amount of moisture transport, across our northern
tier of counties from about the Sherman-Denison area westward
towards Bowie. While the LLJ will likely continue to veer and this
activity will decay---there is the potential for the regeneration
of activity as the cold front, currently across northern OK,
slides southward and interacts with any residual outflow.

Current output from the operational HRRR and TTU WRF both show a
rapid uptick in convection along the I-20 corridor, a result of
what I believe to be a fair amount of mass convergence along the
front and outflow boundary. However, with the front still across
northern OK and the upper trough responsible for a bulk for the
southward progression of said front lifting off towards the
northeast, it appears possible that the front may stall a bit
further to the north than previously thought. As a result, I went
ahead and added a few of our northern most counties to the Flash
Flood Watch. Regardless--- most of the heaviest rain should be
focused near the surface front and subsequent 925/850mb surfaces.
Where these boundaries set up today and tonight is likely where
the axis of heaviest rainfall will reside. Given the very moist
environment and the potential for training convection, it will not
be out of the question that 2" per hour rainfall rates will be
possible. Unfortunately, it is conceivable that this axis
establishes itself right along the I-20 corridor.

For tonight into Sunday morning---Heavy rainfall will continue to
be a threat through tonight as synoptic scale ascent (entrance
region of the upper jet) is expected to continue to overspread the
area. There is a suggestion in the model fields that some sort of
MCV may develop across the Concho Valley. The latest run of the
NAM brings a higher swath of QPF a bit further to the north than
previous runs. The 06 UTC NAM solution is now a bit more in line
with that of the 00 UTC ECMWF brings it into better agreement with
the ECMWF. Output from the tail end of the HRRR and TTU WRF do
show slightly more impressive simulated reflectivity across this
region which adds confidence to introduce Likely PoPs along and
southwest of a Graham to Mexia line through Sunday AM.

For Monday---Rain chances will continue on Monday as the upper air
pattern remains very zonal. The resultant lee-side cyclogenesis
should result in good south flow which should lift what`s left of
the old baroclinic zone towards the north. With continued
WAA and moisture transport, chance PoPs were retained across the
entire CWA, with the better rain chances west of the interstate 35
corridor.


&&

.LONG TERM (Tuesday through Friday)...
For Tuesday---Rain chances will continue as warm/moist air
continues to be transported northward with a pretty stout lee-
cyclone across SW KS. Right now, the overall coverage looks to
really be highest across northwest zones early in the day and I
have maintained the highest PoPs across this area. For Tuesday
night, little to no precipitation is forecast across North and
Central TX as the synoptic scale lift appears displaced to the
north.

For Wednesday and beyond---the better rain chances will return to
the forecast for late Wednesday into Thursday as another cold
front is expected to slide southward towards the region. With the
airmass across the region not being scoured out, there`s a good
chance that heavy rain will be possible, mainly along the northern
third of North TX. Into the weekend, will broad brush PoPs across
the entire CWA as there is too much uncertainty with regards to
where the front will end up.

24-Bain


&&

.AVIATION...

/ISSUED 1202 AM CDT SAT AUG 20 2016/
A wet weather pattern will continue through this TAF period.
At 05z...there were two areas of showers and thunderstorms that
were of concern. 1. Over the Texas Panhandle into western Oklahoma
was moving southeastward. 2. over Southwest Texas moving
northeastward. Expect showers and thunderstorms to move into the
Metroplex toward 09z and continue through the morning hours.
With the onset of the showers/thunderstorms will come MVFR
ceilings. There should be a respite during the early afternoon
before the next round of showers and thunderstorms late afternoon
into the evening. A cold front is expected move into North Texas
late Saturday morning...but will be slow to move. So have kept
south flow. A thing to note is the with the thunderstorm complex
Saturday morning...winds may shift to the north for several hours.

For Waco...expect ceilings to lower to MVFR by 09-11z as showers
and thunderstorms spread into the area. MVFR ceilings are then
expected to remain through 21z. Some improvement to VFR should
occur late afternoon. Expect mostly south flow to prevail outside
of storms.

58


&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    82  71  82  72  87 /  80  80  50  40  40
Waco                84  70  82  72  88 /  70  80  60  40  40
Paris               81  69  85  69  86 /  80  60  40  20  40
Denton              82  69  85  69  86 /  90  70  50  40  40
McKinney            82  70  85  70  86 /  80  80  50  30  40
Dallas              83  72  83  72  87 /  80  80  50  40  40
Terrell             82  71  83  71  86 /  80  80  50  30  40
Corsicana           84  72  82  73  87 /  80  80  60  30  40
Temple              84  72  83  71  87 /  70  70  70  40  40
Mineral Wells       84  67  81  68  83 /  90  80  60  40  50

&&

.FWD Watches/Warnings/Advisories...
Flash Flood Watch through Sunday evening for TXZ091>093-100>104-
115>121-129>135-141>148-156>162-174-175.

&&

$$

05/24



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.