Texas Winter 2020-2021

[Brent]

Just in from FWD

Precipitation is expected to begin developing Saturday night and
continue through Sunday, eventually ending around daybreak Monday.
Forecast soundings show a mix of rain and snow with an eventual
change over to all snow in some areas. The highest snow
accumulation will likely be focused in West Texas and the Big
Country initially, before spreading eastward. The depth of the
cold air limits the potential precipitation types for this event
to rain and/or snow. With this forecast update, there is a notable
increase in QPF and snowfall totals including up to 3 to 5 inches
of snow possible generally along and west of U.S. Highway 281.
While the higher totals are confined to western North and Central
Texas at this time, up to 1-2 inches of snow is possible along the
Interstate 35 corridor. Additionally, with precipitation coming
to an end late Sunday night, impacts to travel may linger into the
Monday morning commute.

[Ntxw]

Wow. One thing to watch though (caution) is the GFS develops low pressure off the coast of Texas and scours out a lot of the precip from the northern trough has it moves further into Texas. Would definitely not be good for snow chances across north Texas if this wins out.

GFS 500mb is quite similar to the NAM, but its surface depictions from run to run is inconsistent.

[foulbeast]

FWD Forecast Discussion update (Long Term)

.LONG TERM... /NEW/
/Friday Night Onward/

Cool and dry conditions will persist across the region Friday
night and Saturday as we remain situated between upper level
systems. A weak shortwave that will quickly traverse the
Central/Southern Plains Friday will have little effect on the
sensible weather across North and Central Texas. Mostly clear
skies and lingering north winds will allow for widespread freezing
temperatures to settle in across the region by daybreak Saturday.

The main headline of the long term forecast period continues to
be the potential for snow on Sunday. An upper level low, expected
to move onshore in the Pacific Northwest Friday, will swing
through the Four Corners region into western Central Texas on
Sunday. If you have been following our discussions about this
system this week, then you are familiar with the inconsistencies
in the forecast track, among other details, as the upper low moves
across the state of Texas. Putting a pin in the track
inconsistencies for a moment, both deterministic and ensemble
models are in general agreement that cold air and moisture will be
in sufficient supply as large scale lift overspreads the region.

Precipitation is expected to begin developing Saturday night and
continue through Sunday, eventually ending around daybreak Monday.
Forecast soundings show a mix of rain and snow with an eventual
change over to all snow in some areas. The highest snow
accumulation will likely be focused in West Texas and the Big
Country initially, before spreading eastward. The depth of the
cold air limits the potential precipitation types for this event
to rain and/or snow. With this forecast update, there is a notable
increase in QPF and snowfall totals including up to 3 to 5 inches
of snow possible generally along and west of U.S. Highway 281.
While the higher totals are confined to western North and Central
Texas at this time, up to 1-2 inches of snow is possible along the
Interstate 35 corridor. Additionally, with precipitation coming
to an end late Sunday night, impacts to travel may linger into the
Monday morning commute.

Now let`s get back to those track variations I mentioned earlier.
The good news is the GFS, ECMWF, and Canadian (among others) are
beginning to show much better agreement in how far south this
system may track. Continuing adjustments in the track are very
likely and will have direct impacts on where the rain/snow
transition line sets up. Overall confidence in the potential for
wintry precipitation is increasing, but this forecast continues to
be far from a slam dunk. Beyond this winter weather event, the
forecast is looking much quieter with dry and gradually warming
conditions throughout the work week. Monday looks to be the
coldest day of the week with afternoon temperatures topping out in
the 40s areawide.

[HockeyTx82]

This board is rocking now.....

[jaguars_22]

So if there was a coastal low develop could this be a situation like in Christmas 2004 for coastal Texas? Or is there not enough cold air in place? Also could the low over southern Texas gain more strength than forecasted and allow for more snow south Texas?

[Ntxw]

Latest RGEM is nearly identical to the NAM.

[orangeblood]

Looks like the FW NWS office is hugging the GFS for some strange reason....IMO blend of NAM and Euro is the way to go at this time

[txtwister78]

Latest RGEM is nearly identical to the NAM.

https://i.imgur.com/bJnypFb.gif

RGEM and NAM though are usually overdone on precip amounts (usually come back to earth closer to the event). NAM3 better but still too far out. They handle temps (NAM particularly) better in my opinion with the cold. The totals on the RGEM are out to lunch quite honestly even though they support where I think heaviest snow will fall. Again just my .02

[Ntxw]

Latest RGEM is nearly identical to the NAM.

https://i.imgur.com/bJnypFb.gif

RGEM and NAM though are usually overdone on precip amounts (usually come back to earth closer to the event). NAM3 better but still too far out. They handle temps (NAM particularly) better in my opinion with the cold. The totals on the RGEM are out to lunch quite honestly even though they support where I think heaviest snow will fall. Again just my .02

The unfortunate part is that these sites will provide 10:1 ratio. Do I think they are going to be 10:1 the whole way? Certainly not but you can ingest the convective nature of this event. The core of the snow on consistent basis of where the heaviest axis is not where the coldest air is, but where the heaviest QPF is. This shows you that we will not have a handle on "amounts" until we get into the range. Coarse models such as the operational will only provide a smoothed generality.

[txtwister78]

Latest RGEM is nearly identical to the NAM.

https://i.imgur.com/bJnypFb.gif

RGEM and NAM though are usually overdone on precip amounts (usually come back to earth closer to the event). NAM3 better but still too far out. They handle temps (NAM particularly) better in my opinion with the cold. The totals on the RGEM are out to lunch quite honestly even though they support where I think heaviest snow will fall. Again just my .02

The unfortunate part is that these sites will provide 10:1 ratio. Do I think they are going to be 10:1 the whole way? Certainly not but you can ingest the convective nature of this event. The core of the snow on consistent basis of where the heaviest axis is not where the coldest air is, but where the heaviest QPF is. This shows you that we will not have a handle on "amounts" until we get into the range. Coarse models such as the operational will only provide a smoothed generality.

Agreed.

[Ntxw]

The area to our west/southwest is where we'll be watching on the HRRR and others for storm/lift formation as the forcing increases out of New Mexico and Northern Mexico come Saturday evening. It will be telling.

[cheezyWXguy]

It may be worth noting that the NAM 3k shows more areas of sub freezing temps at hour 60 (6z Sunday) across north Texas than the NAM 12k does. If the higher resolution equivalent is picking up colder temps, I imagine we will see surface temp depictions for the event cool on the other models as we get closer.

[txtwister78]

18z GFS ENS moved a bit south with totals. Still showing highest amounts from Lubbock (3.5 inches) increasing to just NW of Waco (4.7 inches). Not sure how to post images on here. Quick drop off the further north you go at least on this run.

[orangeblood]

It may be worth noting that the NAM 3k shows more areas of sub freezing temps at hour 60 (6z Sunday) across north Texas than the NAM 12k does. If the higher resolution equivalent is picking up colder temps, I imagine we will see surface temp depictions for the event cool on the other models as we get closer.

As opposed to most other winter events around here, I’m really not that concerned about temps....very cold sub-freezing temps just a few hundred ft up with no warm nose to deal with

[txtwister78]

It may be worth noting that the NAM 3k shows more areas of sub freezing temps at hour 60 (6z Sunday) across north Texas than the NAM 12k does. If the higher resolution equivalent is picking up colder temps, I imagine we will see surface temp depictions for the event cool on the other models as we get closer.

I'm not sure you want it to get too much colder though if you're a fan of more snow across North Texas. Globals are always a bit warm with these scenarios and so I would expect HI Res to come in a few degrees colder, however that could make all the difference in terms of where the best QPF lines up as mentioned above.

[orangeblood]

18z GFS ENS moved a bit south with totals. Still showing highest amounts from Lubbock (3.5 inches) increasing to just NW of Waco (4.7 inches). Not sure how to post images on here. Quick drop off the further north you go at least on this run.

GFS ENS members don’t handle temp profiles like this very well so snow totals may look off....I’d follow QPF trends which looks to be anywhere from 0.3 to 0.6 across DFW at this time

[Brent]

Steve McCauley has spoken y'all it's happening

[HockeyTx82]

Steve McCauley has spoken y'all it's happening

https://i.ibb.co/r7rZ4th/Screenshot-20210107-170315.png

What's the not all caveat?

[Brent]

Steve McCauley has spoken y'all it's happening

https://i.ibb.co/r7rZ4th/Screenshot-20210107-170315.png

What's the not all caveat?

that was the stay tuned part

[Ntxw]

0z is going to be nailbiters again! Though I don't believe there will be any drastic changes in the overall pattern, as mentioned before once you get under 100 hours (even less now) the models are really good nowadays with the broad view. We'll be looking for pixels of thundersnow and who gets the most!