January 2022

[Stratton20]

Note this includes sleet but the GFS has widespread accumulations, which is odd because it only shows a small pocket of sleet in houston

[Kingwood36]

It's going to change another 10 times so I wouldn't worry about it

[don]

Note this includes sleet but the GFS has widespread accumulations, which is odd because it only shows a small pocket of sleet in houston

You have to look at the model soundings to see the precip type.You cant take the output you see on the maps as verbatim (due to the low resolution).A lot of the rain you see the model showing based on soundings would actually be sleet over the metro late Thursday night into Friday morning.As a subfreezing pocket of air forms above the surface.

[Stratton20]

Don interesting! thanks for explaining that

[Stratton20]

FWIW this cold pattern could be sticking around for a while, late next week the GFS is indicating another shot of some really cold arctic air that could be on the table

[Cpv17]

FWIW this cold pattern could be sticking around for a while, late next week the GFS is indicating another shot of some really cold arctic air that could be on the table

Yeah man I just saw that and was gonna come here to post it. Looks like that’s about 8 days out so that’s not really in fantasy land either. Looks like there could be a chance for some more winter weather with that one too. Very interesting.

[jasons2k]

FWIW this cold pattern could be sticking around for a while, late next week the GFS is indicating another shot of some really cold arctic air that could be on the table

So that brought me out of hibernation. We’ll see if that continues…
Would be cold for sure!

[Cpv17]

FWIW this cold pattern could be sticking around for a while, late next week the GFS is indicating another shot of some really cold arctic air that could be on the table

So that brought me out of hibernation. We’ll see if that continues…
Would be cold for sure!

Looks like the 0z Euro is onboard too but it’s not quite as strong with the high pressure cell as the GFS is.

[Iceresistance]

Ntxw (Moderator on S2K) has pointed out that even though that February could have a very similar -PNA like December, the pattern won't be, the La Nina is dying away.

[Stratton20]

06z gefs back at it with a near winter storm like setup

[Iceresistance]

06z gefs back at it with a near winter storm like setup

I wished I had WeatherBell, you needed a Paid Subscription to see the models.

[Kingwood36]

06z gefs back at it with a near winter storm like setup

So it was just a bad run

[Kingwood36]

Jeff doesn't seem to buy into anything except north and west of hwy 105..



"Thursday:
Strong cold air advection will onset and expect temperatures to remain in the 30’s and low 40’s for the day. NAM guidance has been trending colder which is usual in these sort of cold air intrusions and would not be surprised if most areas remained in the 30’s all day. WSW/SW flow aloft will remain in place over top of the building surface cold dome and a short wave trough will approach Thursday afternoon and evening from the west. This trough will spread lift across the region and work with the remaining limited moisture to produce light precipitation. Strong northerly winds will be in place on Thursday resulting in wind chills in the 10’s and 20’s over the region.

Thursday night:
Warm layer (nose) noted in forecast sounding Thursday afternoon begins to erode over the area with profiles becoming more conducive for sleet or a mixture of sleet/rain/freezing rain mainly north of HWY 105. Moisture is still available in the evening hours, but between midnight and 600am on Friday the moisture begins to shift southward and drier air from the north works in. Surface freezing line will progress southward on Thursday evening and reach a line from roughly Huntsville to Hempstead to Columbus by late evening and possibly as far south as I-10 by Friday morning. Think the greatest potential for the moisture and cold air to overlap will be NW of a line from Livingston to Columbus where a transition from rain to freezing rain and sleet will be possible. Toward I-10 including the northern portions of Harris County sleet could mix with the light rain on Thursday night and there may be a brief period where light rain/drizzle could briefly freeze if the 32 line can get into northern Harris County…think this is slightly more likely into Waller and Montgomery Counties.

Impacts:
Ground temperatures will be warm on Thursday and Thursday night given mid 70’s likely on Wednesday and only about 24 hours of cold air across these surfaces. Elevated surfaces (trees, powerlines, rooftops, bridges) may cool closer to the air temperature yielding some potential for light icing on these surfaces from any freezing rain or drizzle. Precipitation amounts look to be on the low side….maybe .05 to .20 of liquid with the higher amounts closer to the coast where temperatures will be above freezing. Overall not expecting any accumulations at this time, although an icy patch on a bridge or light ice on trees and power lines is possible especially north of HWY 105.

Confidence:
As with most winter weather events in SE TX, the confidence on where the surface freezing line will be along with what type of precipitation may fall is always low confidence until close to the event. Many of the parameters with this upcoming event are marginal with both the cold air and moisture. Will see how models guidance trends today and see what the shorter range guidance outputs as we move into that time period later today into Wednesday."

[don]

12Z NAM coming in colder with frozen precip all the way to the coast.BTW this is a very similar setup to the "surprise" snow of December 2017.

[Iceresistance]

Jeff doesn't seem to buy into anything except north and west of hwy 105..



"Thursday:
Strong cold air advection will onset and expect temperatures to remain in the 30’s and low 40’s for the day. NAM guidance has been trending colder which is usual in these sort of cold air intrusions and would not be surprised if most areas remained in the 30’s all day. WSW/SW flow aloft will remain in place over top of the building surface cold dome and a short wave trough will approach Thursday afternoon and evening from the west. This trough will spread lift across the region and work with the remaining limited moisture to produce light precipitation. Strong northerly winds will be in place on Thursday resulting in wind chills in the 10’s and 20’s over the region.

Thursday night:
Warm layer (nose) noted in forecast sounding Thursday afternoon begins to erode over the area with profiles becoming more conducive for sleet or a mixture of sleet/rain/freezing rain mainly north of HWY 105. Moisture is still available in the evening hours, but between midnight and 600am on Friday the moisture begins to shift southward and drier air from the north works in. Surface freezing line will progress southward on Thursday evening and reach a line from roughly Huntsville to Hempstead to Columbus by late evening and possibly as far south as I-10 by Friday morning. Think the greatest potential for the moisture and cold air to overlap will be NW of a line from Livingston to Columbus where a transition from rain to freezing rain and sleet will be possible. Toward I-10 including the northern portions of Harris County sleet could mix with the light rain on Thursday night and there may be a brief period where light rain/drizzle could briefly freeze if the 32 line can get into northern Harris County…think this is slightly more likely into Waller and Montgomery Counties.

Impacts:
Ground temperatures will be warm on Thursday and Thursday night given mid 70’s likely on Wednesday and only about 24 hours of cold air across these surfaces. Elevated surfaces (trees, powerlines, rooftops, bridges) may cool closer to the air temperature yielding some potential for light icing on these surfaces from any freezing rain or drizzle. Precipitation amounts look to be on the low side….maybe .05 to .20 of liquid with the higher amounts closer to the coast where temperatures will be above freezing. Overall not expecting any accumulations at this time, although an icy patch on a bridge or light ice on trees and power lines is possible especially north of HWY 105.

Confidence:
As with most winter weather events in SE TX, the confidence on where the surface freezing line will be along with what type of precipitation may fall is always low confidence until close to the event. Many of the parameters with this upcoming event are marginal with both the cold air and moisture. Will see how models guidance trends today and see what the shorter range guidance outputs as we move into that time period later today into Wednesday."

It always seems like that 105 is the Divider for SE Texas weather.

My Dividers are US-81 & I-35 for the Dryline, I-40 & I-44 for Fronts, Freezing lines, & storm systems.

[Kingwood36]

Hwy 105 isn't very popular on this board

[srainhoutx]

12Z NAM coming in colder with frozen precip all the way to the coast.BTW this is a very similar setup to the "surprise" snow of December 2017.

Glad to see the December 2017 event mentioned! Kudos Don for recognizing the synoptic setup. Overrunning precipitation over a very dense cold air mass spells trouble from a forecasting standpoint. Typically the outcome is not known until the precipitation begins to fall and what the actual surface and aloft temperatures are.

Keep an eye on the guidance around 48 hours prior to the event and check the soundings.

[Stratton20]

Id say by tommorow evening we will have a much clear picture on what will occur early friday morning

[Kingwood36]

57 doesn't believe the nam... cold rain

[Cpv17]

57 doesn't believe the nam... cold rain

Well duh. It’s not showing temps in the 70’s so of course he doesn’t lol