100 
FXUS64 KFWD 030931
AFDFWD

Area Forecast Discussion
National Weather Service Fort Worth TX
331 AM CST Sun Feb 3 2019


.SHORT TERM...
/Through Tonight/

In wake of yesterday's departing shortwave trough, weak upper
ridging will prevail today. Meanwhile, another upstream shortwave
will traverse the Rockies today, leading to increased lee 
cyclogenesis. This pattern will keep the Southern Plains within a 
warm advection regime with moist southerly flow prevailing. 

Widespread low stratus and some fog exists across the forecast
area this morning with ample moisture within the lowest 3 kft.
While visibilities may occasionally drop to around a mile or less
throughout this morning, widespread dense fog is not expected at 
this point. The thickest fog is generally expected across parts 
of Central Texas through mid morning. Otherwise, continued warm 
advection has supported some very light showers or sprinkles 
across our southeastern zones overnight which may linger through 
the morning before exiting to the east. Outside of these isolated
showers and some occasional mist or drizzle this morning, most 
areas will remain dry today. 

The high dewpoints and widespread clouds have kept temperatures
mild overnight, with most locations beginning the day in the mid 
50s to near 60 degrees. Later today, low-level flow will veer 
slightly in response to the aforementioned increasing cyclogenesis
to our northwest. The slight westerly component within the low- 
level flow should help to gradually erode the cloud deck from west
to east throughout the day while an ill-defined Pacific front 
boundary drifts slowly eastward towards the forecast area. With 
skies expected to go broken or scattered west of I-35 this 
afternoon, temperatures should be capable of climbing well into 
the 70s, or even near 80 degrees across some of our western 
counties. Farther east, stubborn cloud cover should prevent 
temperatures from climbing out of the mid 60s to near 70. The 
tightening surface pressure gradient will also mean increased wind
speeds, with winds of as high as 20-25 mph possible this 
afternoon. 

As the low-level cloud deck erodes later today, additional mid-
level clouds will spread into the area from the west later this
afternoon and evening. While this may lead to the appearance of
some echoes on radar, precipitation from this cloud deck appears
rather unlikely with some much drier air located just beneath the
cloud base. These clouds along with lingering low stratus in East
Texas should help keep overnight lows on the warm side, in the 
mid 50s to low 60s. Fog may redevelop across some of our southern 
and eastern zones by daybreak Monday where dewpoints will climb 
into the low 60s overnight. However, persistent winds around 10 
mph should prevent it from becoming widespread or dense. 

-Stalley

&&

.LONG TERM...
/Monday through Saturday/

Well above normal warmth is anticipated through at least mid-week.
Morning to early afternoon cloud cover/drizzle is anticipated with
low rain chances across parts of the area. From mid-week and into
next weekend, conditions will change quite noticeably as a strong
front plows southward through the area. Increased chances for
showers and storms will accompany this front along with much
colder conditions. Rain chances will linger into next weekend.

Monday and Tuesday---Rich boundary layer moisture will be 
transported northward beneath a decent capping inversion. While 
lapse rates are somewhat steep above the cap, there appears to be 
little in the way of forcing for ascent. This should mean only 
drizzle/fog in the morning hours on Monday and again on Tuesday, 
mainly for areas near and southeast of a Lampasas to Waco to 
Canton line. Drizzle/fog may be possible elsewhere, but at this 
time, the best potential is across the aformentioned geographic 
area. On Monday afternoon, surface to 850mb flow will veer sharply
ahead of cold front that is forecast to dive southward out of the
Central Plains. All indications are that this front should remain
north of the Red River. The veered low levels should help to 
scour out low level moisture (and thus drizzle/fog and clouds) and
will likely promote rapid warming due to increased adiabatic 
compression. High temperatures will be greatest west of I-35
(highs in the low 80s) with slightly cooler conditions across 
East Texas(highs in the low 70s) where cloud cover will linger 
and the downslope component will not be as great. 

Tuesday should feature another day of unseasonably warm 
conditions, though highs will be tempered some thanks to the 
greater degree of cloud cover. Low level flow does not appear to 
veer as sharply in model wind fields...with the exception being 
across the Big Country where temperatures may still climb to near
80 degrees. The depth of moisture should increase some and 
capping will not be as strong with backed low level flow, 
especially across East Texas. Forcing for ascent---outside of 
WAA---appears meager and I've undercut blended model guidance and
will only advertise a 10-15 PoP with a few showers. Otherwise, 
there will be a risk for a few pockets of drizzle/fog, mainly 
during the morning hours. Late Tuesday, some guidance suggests 
that some weak convection will be possible along the Red River and
across parts of East Texas. It appears that some of the model 
guidance may be attempting to produce some precipitation due to 
modest surface convergence along the front discussed above. For 
now, I'll maintain a rain-free forecast during this time for a 
couple of reasons. 1) Forcing for ascent appears meager on the 
synoptic scale and 2) It's a little difficult to identify any 
mesoscale influences that would result in rain and/or storms. As 
we get closer to Tuesday, we should have a better handle on 2) 
with the assistance from hi-res NWP. 

Wednesday and Thursday---Wednesday will be a little cooler thanks
to denser and more widespread cloud cover. Capping will 
be reduced further and WAA should be enough to kick off some 
isolated to widely scattered showers during the morning and 
afternoon hours on Wednesday. Slightly stronger breezes are 
expected on Wednesday as the surface pressure gradient tightens 
some. Rain chances will increase quickly Wednesday night and into 
Thursday with the approach of our next big cold front. Model 
guidance has converged with respect to the timing of FROPA. The 00
UTC GFS is now slightly faster than the 00 UTC ECMWF and 
Canadian. PoPs advertised by the blends seem reasonable, though 
I'll cap rain/storms chances off at 60% given that there will
likely be some spatiotemporal changes to the PoP forecast. There 
appears to be sufficient instability for thunderstorms late 
Wednesday and into Thursday. CAPE values will near 1500 J/kg with 
deep layer shear values on the order of 40 knots. These
ingredients could support some organized storm modes, however, there
are a few of things that could preclude a severe weather episode.
The first is the speed of the front with respect to the storm 
motion. With deep layer shear vectors largely parallel to the 
front, it's possible that updrafts will be undercut quickly.
Finally, the time of day may be slightly unfavorable for surface
based convection. In addition, if cloud cover hangs tough through
the day, the aformentioned forecast CAPE values may be overdone. 
Lapse rates do climb close to 7 C/km, however, and if storms do 
realize forecast CAPE values and can remain out in the warm 
sector away from the front, there could be a threat for strong to
severe storms.

Friday and Beyond---After above normal warmth, Friday and into 
the weekend will see much colder conditions. Strong north winds 
below 850mb should ensure that colder air filters southward into 
North and Central Texas. 700mb flow, however, appears as if it 
will quickly become southerly...possibly in response to the 
thermally direct circulation associated with the entrance region a
strong upper level jet. This would result in a decent amount of
isentropic upglide atop the colder near surface layer and thus a
good setup for post-frontal stratiform precipitation. Previously,
the GFS and some of its ensembles were the lone camp that 
advertised this scenario. Closer inspection of the latest ECMWF 
guidance is more in line with the GFS/GEFS solutions and I've 
nudged PoPs upward some late Friday and into Saturday. At this 
time, it appears that most locations should be warm enough such 
that all precipitation remains just a cold rain. The exception to 
this may be along the Red River, though moisture depth likely 
would support more in the way of freezing drizzle. For now, I'll 
keep the entire forecast void of any winter precipitation, but 
it'll be something to keep an eye on.


Bain

&&


.AVIATION... /Issued 1128 PM CST Sat Feb 2 2019/
/06Z TAFs/

Stratus will continue to surge northward overnight in response to
deepening surface low pressure across the Central and Southern
High Plains. MVFR to high end IFR ceilings will slowly lower
through the night with all TAF sites falling below 1000 ft before
sunrise. Visibility will also fall between 3 and 5 miles but
breezy southerly winds overnight/Sunday morning should prevent 
dense fog from developing. Ceilings will slowly lift by mid 
morning but will remain below 3000 ft until mid afternoon Sunday. 

A few sprinkles or brief light rain will be possible through the
night generally east of Waco so no impacts to the TAF sites are 
anticipated.

A south to southeast wind will prevail through Sunday evening at
speeds between 8 and 13 knots tonight and 12 and 16 knots on 
Sunday along with some higher gusts. 


79

&&

.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth    73  60  80  60  76 /   5   0   0   5  10 
Waco                73  61  79  60  76 /  10   0   0   5  10 
Paris               68  61  76  58  73 /  10   5   0  10  20 
Denton              72  58  78  57  76 /   5   0   0   5  10 
McKinney            70  59  77  58  75 /  10   0   0   5  10 
Dallas              72  60  80  61  76 /   5   0   0   5  10 
Terrell             71  61  77  60  74 /  10   0   0  10  10 
Corsicana           71  63  78  61  76 /  10   5   0  10  20 
Temple              73  61  78  60  76 /   5   0   0   5  10 
Mineral Wells       74  56  81  56  78 /   0   0   0   0  10 

&&

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

$$

24/26