If the 00z GFS were to verify, it would be a cold rain mixed with snow, especially if you're north of I-10. Temperatures below freezing down to around 950-960mb (~2000 ft). With a below freezing and a saturated lower-mid level column, wet-bulbing would likely help cool the surface down enough for some snow to mix in.. The trajectory of the low though really has big implications of what we see and how much moisture we are working with.
First image below is 18z (noon Sunday). Image below that is 00z (6pm Sunday). Notice how quickly we begin drying out with cold air advecting in behind the front. Moisture as I said before looks limited and we'll quickly be drying out as the day goes on, so even if we get some of the white stuff, I'm not seeing any surprises for accumulation, especially with ground temperatures being so warm with the nice several days in the 70s. Though I won't mind if I'm wrong... we'll just need the CMC to verify in that case...
The ground will not be warm since we will have a good front plow through today and the cold air looks to stay around ahead of the next system. I don't see that being an issue IF we do get snow.
Area Forecast Discussion
National Weather Service Houston/Galveston TX
423 AM CST Wed Jan 6 2021
.SHORT TERM [Through Thursday Night]...
Surface low, currently situated in southwest OK and TX Panhandle
will track to the ese along the Red River today. Associated cold
front, oriented nne-ssw, will move across the region this
afternoon and off the coast early this evening. In advance of the
front, southerly llvl jet will increase to around 40kt bringing
deeper Gulf moisture into the area. PW`s are fcst to increase into
the 1.2-1.5" range. Look for increasing shra/tstm coverage this
afternoon with the aid of large scale lift from the advancing
upper trough and incoming LFQ of jet. Anticipate this precip to
eventually consolidate into a line of convection along the frontal
boundary as it pushes across the area in the noon-7pm timeframe.
Some strong to severe storms are possible - with the primary
threat being straight line winds in the embedded stronger portions
of the line of convection. That said, there is also a non-zero
chance of a tornado considering ample sheer/helicity values,
especially for any discreet cells that manage to develop in
advance. Considering the available moisture, wouldn`t doubt if we
some see an isolated 2-3" (more favorable n-ne of the metro area),
but with a fairly progressive system think most of the region
will see less than that and flash flood issues, if any, to be
quite localized.
Precip will come to an end as the front passes with breezy
conditions in its wake. Cooler, dry conditions tonight and
Thursday with the potential for some wrap around cloud cover
across the ne half of the CWA. 47
.LONG TERM [Friday through Tuesday Night]...
When the extended period begins, dry and cooler than average
temperatures are expected Friday and Saturday as a surface high
pressure builds into the region. Daytime temperatures will only
reach the mid to upper 50s Friday and Saturday.
Attention then turns to an upper-level trough tracking eastward
from the Rockies late Saturday, and a coastal surface low pressure
over southeast TX/northeast MX. This scenario looks to be our
next chance at widespread precipitation on Sunday. Differences
continue in exact track and QPF, but confidence continues to
increase that precipitation will occur. Latest GFS and CMC
guidance suggest a faster solution, bringing most of the
precipitation by Sunday morning and afternoon, while the ECMWF
continues to be a few hours slower. The main concern with this
event will be precipitation type. Thermal profiles from CMC
suggest p-type will be all liquid. However, the GFS/ECMWF and
EC/GEFS clusters and plumes are the coldest solutions; exhibiting
a large spread on QPF amounts, p-type and 850 mb temperatures.
That said, tried hedging forecast a bit more towards GFS/ECMWF
solutions, bringing a small/brief window of rain-snow mix across
our northern counties. Overall, the preferred solution would bring
increasing chances of precipitation late Saturday night into
Sunday evening. Depending on where the surface low tracks and
deepens, this will determine the quantity of warm air advecting
into the region; hence, p-type and amounts. Keep in mind that
this forecast will change as the system evolves.
Quiet weather is expected in the wake of this system with
temperatures near to slightly below normal. Daytime highs will
mainly be in the 50s Monday and Tuesday. Overnight lows in the 30s
and low 40s. 05
&&
.AVIATION [12Z TAF Issuance]...
A mix of MVFR/VFR cigs are expected today. A cold front will
cross the region during the 18-00Z (CLL to GLS) timeframe with an
associated line of showers and thunderstorms...some of which could
be strong to severe (winds being the primary threat). Skies
should begin to clear from west to east after the frontal passage
and nw winds will become breezy. VFR conditions are expected
overnight, though we may see some wrap-around cloud cover sneak
back in across parts of the area bringing some sct/bkn 2000-3000
ft decks late. 47
&&
.MARINE...
Expect southerly winds to strengthen today in advance of a cold
front that will be pushing off the coast early this evening. A
line of showers and thunderstorms, some possibly strong to severe,
will likely accompany the front. Precipitation will end and
moderate to strong northwest winds are anticipated as the front
passes. Small Craft Advisories will be required. Potential is
there for some low water conditions in the bays during the low
tide cycles Thursday. Current fcst guidance shows levels just
above the -1 MLLW criteria needed for an advsy but it`ll need to
be monitored. Winds and seas will diminish Thursday night and
Friday. A coastal low is expected to develop off the lower Texas
coast Saturday night and Sunday bringing some unsettled weather
and another increase of winds and seas. 47
TX...None.
GM...SMALL CRAFT SHOULD EXERCISE CAUTION from noon CST today through
this afternoon for the following zones: Coastal waters from
Freeport to Matagorda Ship Channel TX out 20 NM...Coastal
waters from High Island to Freeport TX out 20
NM...Galveston Bay...Matagorda Bay...Waters from Freeport
to Matagorda Ship Channel TX from 20 to 60 NM...Waters from
High Island to Freeport TX from 20 to 60 NM.
Kingwood36 wrote: ↑Wed Jan 06, 2021 9:04 am
I'm honestly suprised it's still showing in the models I figured they would of already lost it by now or pushed it up north around dallas
redneckweather wrote: ↑Wed Jan 06, 2021 7:50 am
The ground will not be warm since we will have a good front plow through today and the cold air looks to stay around ahead of the next system. I don't see that being an issue IF we do get snow.
When it snows around here they usually don’t put it in the forecast till the day of or the day before it happens. When it’s 2 or more days out they never really forecast snow. They always say it’ll just be a cold rain.
Cromagnum wrote: ↑Wed Jan 06, 2021 10:34 am
So what part of the day is it expected to get feisty around here today? I dont want to be in rush hour traffic if its going to be storming.
It’s going to be close, models struggle so bad with winter weather down here, icon model looks good. Main thing is looks like this is will be a good chance of happening
Cpv17 wrote: ↑Wed Jan 06, 2021 10:31 am
12z GFS trended warmer. Snow now up in NTX. A cold soaking rain down here. Seems like it has more moisture to work with now though so at least that.
Yep,It trended warmer because of warm nosing since the gulf low is closer to the coast.Which will be vital in determining who gets snow or just a cold rain.At the same time if you prefer heavy rain,then the low being closer would help to boost rainfall totals.But this is a needle and thread scenario where it will be hard to get both its either a decent rain setup or a snow event depending on how much cold air or warm air advection we have in the area.
Last edited by don on Wed Jan 06, 2021 11:05 am, edited 1 time in total.
