NWS Area Forecast Discussion
857
FXUS64 KFWD 210559
AFDFWD
Area Forecast Discussion
National Weather Service Fort Worth TX
1159 PM CST Mon Jan 20 2025
...New Aviation...
.KEY MESSAGES...
- Minor snowfall accumulations up to 1 inch will be possible in
our southeast counties. A Winter Weather Advisory is in effect
for this area tonight.
- Wind chills will range between 5 and 15 degrees Tuesday and
Wednesday morning.
- A warmup closer to normal temperatures is expected through the
end of the week.
&&
.SHORT TERM... /Issued 728 PM CST Mon Jan 20 2025/
Update:
In general, the trends discussed below remain on track, therefore
no significant changes were made to the previous forecast. Mid-
level cloud cover resulting from weak to moderate isentropic
ascent between 550-750mb has held temperatures lower than expected
this afternoon which means several areas west of the I-35
corridor and along the Red River Valley have remained near or
below freezing today. Adjustments have been made to near-term
grids to incorporate recent observations. Additionally, there
continue to be light radar echoes near and north of the I-20
corridor indicative of snow falling from around 5,000 to 8,000
feet above the surface. However, as low-level winds continue to
turn more northerly, any attempt at moistening in the lower levels
will likely be fighting dry air from the northeast which is
bolstering the dry sub-cloud layer.
Though there haven`t been many reports of precipitation north of
I-20, there has been a noticeable blossoming of light radar echoes
across Central Texas over the last few hours with even a few
isolated reports of very small snow grains reaching the ground in
Limestone and McLennan County. Forecast soundings across Central
Texas show the dendritic growth layer, the favored region for snow
formation, remains on the drier side. The layer below that
(~650-750 mb) is the nearest to saturation with temperatures
closer to 0 C than -10 C. This may be causing an increased
concentration of supercooled water which when falling through sub-
freezing air has formed these small pellets or grain-like
particles. Light snow is expected to remain the predominant
precipitation type as isentropic ascent begins to strengthen
through the evening and overnight. There have been no changes to
the Cold Weather Advisory or Winter Weather Advisory with this
update.
12
Previous Discussion:
/This Afternoon through Tuesday Night/
Water vapor imagery shows an upper trough over the Four Corners
region beginning to eject eastward into the base of a broader
longwave trough over the Central and Eastern CONUS. Ahead of this
feature modest isentropic ascent between 800-600 mb has resulted
in an area of thick cloud cover across much of Central and North
Texas. Farther south, surface pressure falls via cyclogenesis are
occurring across the western Gulf ahead of the upper trough. As
this system spreads east later tonight, low level moisture will
increase and widespread wintry precipitation is expected to
develop across parts of south and southeast TX. Developing
northerly winds on the back side of the surface low over the Gulf
will help reinforce a frontogenetic zone across Central TX which
will be the focus for precipitation tonight. This band of
925-850 mb frontogenesis will be just south of our area, and the
heaviest of any snowfall will be displaced well to our southeast.
Given the limited amount of time for sufficient moisture to get
into our area, snowfall accumulations are expected to generally be
light. Forecast soundings also indicate a fairly unfavorable dry
environment below the cloud deck which will allow initial snow to
sublimate before any accumulation occurs. There is a limited
window of about 3-6 hours where accumulations may occur across our
far southeast counties late tonight. Based on all of the available
model guidance, we`ve lowered snowfall totals to around 1 inch
across mainly our three southeastern most counties. Farther north
and west, anywhere from a dusting to around 1/2" will be possible.
Even farther north along the I-20 corridor toward the Red River,
strong mid level forcing for ascent may squeeze out any available
moisture resulting in some flurries or a light dusting. Given the
relatively dry snow expected, only minor impacts would be expected
on any roads where snow can accumulate. Precipitation will quickly
end early Tuesday morning as the whole system moves east. A Winter
Weather Advisory will remain in effect for our southeast counties
through mid Tuesday morning.
Cold temperatures will continue to be the main hazard through
Tuesday with overnight lows expected to drop into the upper teens
and low 20s tonight with wind chills in the 5 to 15 degree range.
The Cold Weather Advisory will continue into Tuesday morning.
We`ll see temperatures warm into the mid 30s Tuesday afternoon as
skies clear from west to east. A cold night is expected Tuesday
night with lows in the lower 20s.
Dunn
&&
.LONG TERM... /Issued 248 PM CST Mon Jan 20 2025/
/Wednesday through Monday/
A progressive pattern will continue through the end of the week
with a warmup expected into the weekend and some increasing
rain/storm chances. Southerly winds will return on Wednesday ahead
of yet another upstream shortwave rotating through a broad
longwave trough over the eastern 2/3rds of the CONUS. Moisture
will be scant during this time though, so despite modest forcing
for ascent, a weak front will pass through generally unnoticed.
Weak mid level ridging will then spread across the Southern Plains
Thursday and Friday allowing another return to southerly low level
flow and we`ll get a little more moisture pulled northward. High
temperatures will nudge upward each afternoon to near 60 by Friday
and into the mid 60s on Saturday, especially west of I-35.
Models are in fairly good agreement with a late week trough
digging through southern California by late Saturday. Surface
cyclogenesis across southeast Colorado will help strengthen
southerly flow into the Plains and a surge of moisture will race
northward. As stronger forcing spreads eastward well ahead of the
trough, a cold front will slide southward and we should see
scattered showers and a few thunderstorms develop as early as
Saturday evening into early Sunday. Ensemble cluster analysis of
the 500 mb pattern is in really good agreement, particularly with
respect to moisture this far out with nearly 90% of the guidance
indicating measurable rainfall. While still several days out, this
supports an uptick in PoPs to 30-50% for areas east of I-35. We`ll
continue to monitor this next system over the coming days.
Dunn
&&
.AVIATION... /NEW/
/06Z TAFs/
All North Texas TAF sites will remain VFR through the rest of
this TAF cycle. Northerly winds are ongoing and will persist
through 23Z before southwesterly winds return to the area. There
is a low chance of MVFR clouds temporarily moving across North
Texas between 11-13Z this morning, however, the probability is too
low to include in the TAF. Clear skies will prevail beyond 23Z
with no significant weather expected.
For Waco, light snow is ongoing in the vicinity of KACT, and will
likely continue through 08Z. A band of slightly heavier snow is
shifting southward, likely reaching KACT in by 07Z. A light
dusting of snow can be expected with this round. Beyond 08Z, dry
weather is expected with an VFR deck in place through the rest of
the morning. Similar to North Texas, southwesterly winds will
return closer to 00Z as skies become clear.
Hernandez
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 21 36 23 51 29 / 10 0 0 0 0
Waco 23 37 20 50 26 / 30 5 0 0 0
Paris 20 33 21 45 25 / 10 0 0 0 0
Denton 13 35 17 51 24 / 10 0 0 0 0
McKinney 16 35 19 49 25 / 10 0 0 0 0
Dallas 21 37 23 50 29 / 10 0 0 0 0
Terrell 20 36 19 48 25 / 10 0 0 0 0
Corsicana 24 39 22 49 27 / 20 5 0 0 0
Temple 21 39 15 52 25 / 40 10 0 0 0
Mineral Wells 17 37 20 55 24 / 10 0 0 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory until 9 AM CST Tuesday for TXZ091>095-
100>107-115>123-129>135-141>148-156>162-174-175.
Winter Weather Advisory until 9 AM CST Tuesday for TXZ147-148-
158-160>162-174-175.
&&
$$
NWS FWD Office Area Forecast Discussion
