TX Winter Wx Threat # 10---cool/cold and wet?

[Extremeweatherguy]

I think it is worthy to note that we now have a solid 1047mb high pressure system in NW Canada right now (as of the latest HPC map). This is 8mb stronger than it was yesterday evening and it is 5mb stronger than was analyzed by the 18z GFS.

Seems like that one real missing element, (besides very cold air), of previous days, is finally starting to show up. We will need to watch and see what happens with this in the next day or two, because If it can maintain itself or strengthen further then it could potentially be a big factor in the forecast for the coming weekend and next week (since the stronger highs tend to sink further south).

I will be watching this one closely!

http://www.hpc.ncep.noaa.gov/sfc/90fwbg.gif

7:50pm update: The high is still holding about steady, and is at 1046mb now. Still very strong (and a lot stronger than the 1041mb high that the GFS had shown up there for this hour).

[Air Force Met]

http://www.hpc.ncep.noaa.gov/sfc/satsfcnps.gif

The high is now up to 1045-1047mb this afternoon. That is a lot stronger than in what yesterday (a 6-8 mb rise), and as far as I can see, it is also much stronger than was expected.

What is your take on this AFM?

Sorry...been out and about since this afternoon.

As I stated a few days ago...models have a real hard time predicting the strength of these highs. That is a real strengthening of the high. BUt looking back from earlier model runs...it was within 3-4 MB of what it said would be there. That could be a simple matter of the wrong initialization pressure being given...which is why it was higher than what was forecasted. You see that A LOT in the GFS (with highs and lows...remember the tropics anyone?).

What I do notice is there is not a lot of cold air associated with this high. In the Yukon and NW terr.'s, it is just below zero. IN the southern Yukon...its in the teens. In northern BC...its in the 20's. In Alberta it is in the teens and 20's. YOu have to get over to Sask. and Man. to get into the colder air.

So...if the high builds really big and does do a lee side slide...it will slide with air near zero...when it usually does it with air -20 to -30 or colder. Do the math...consider a due south slide and a 40-50 degree modification (which is normal on these types of highs). Also consider that since the colder air is located well east of the ridge axis...that is where its going to get coldest...east.

So...I still think we are on track for a 12-15 degree below normal low on Sunday morning. That means 27-30 at IAH. Then by Monday we should start to warm up.

[Air Force Met]

http://www.hpc.ncep.noaa.gov/sfc/90fwbg.gif

7:50pm update: The high is still holding about steady, and is at 1046mb now. Still very strong (and a lot stronger than the 1041mb high that the GFS had shown up there for this hour).

I just addressed some of this...but the GFS proves my point. Go back and look at the 18z run/00hr and you will see it initialized at 1042. Thats about 5-6 mb too low. I have not been paying attention to the past intializations...but I bet if we were to go back and look...the GFS and the NAM were probably initializing that high too low...especially the GFS. Since the GFS only initialized it at 18Z with a 1042mb...and looking back at the 12Z...it was only a ridge in that area with the highest pressures of 1036-1038 where that 1041 bubble high was...then that explains why it's too low.

So..it's actually forecasting the right strengthening...its initial numbers are just too low. So...to get the right number...add 4-6 mb to what you see and it should be real close. Its not missing the strengthening...its missing the initialization. Its the same thing we see during hurricane season with these tropical storms of 996 mb and the GFS initializes then as a 1005 mb low.

[galvbay]

9:08pm and POURING in Deer Park. Looks like we may getting the end of this last group. I'm ready for some sunshine. galvbay

[Extremeweatherguy]

Thanks for the response AFM. That was a nice explanation.

BTW, I too was noticing the lack of cold air associated with the high and wondered this: Is it possible for cold air to build under that high before it sinks south? Or is that something that will not happen?

From my own amateur observation, there has seemed to be at least a slight cooling under the high within the last few hours (-16F at Colville Lake in the NW Territory as of 9pm), but I wondered if this could be "real" cooling taking place or just typical temperature variations.

http://www.findlocalweather.com/weather ... anada.html
^^I also am noticing some gradual cooling under the high on this map over the last few hours.^^

[Air Force Met]

Thanks for the response AFM. That was a nice explanation.

BTW, I too was noticing the lack of cold air associated with the high and wondered this: Is it possible for cold air to build under that high before it sinks south? Or is that something that will not happen?

From my own amateur observation, there has seemed to be at least a slight cooling under the high within the last few hours (-16F at Colville Lake in the NW Territory as of 9pm), but I wondered if this could be "real" cooling taking place or just typical temperature variations.

http://www.findlocalweather.com/weather ... anada.html
^^I also am noticing some gradual cooling under the high on this map over the last few hours.^^

There won't be any real cooling under that high. This time of year...especially as the high starts to sink south...you start getting sunlight and plus in order to be a good source region...it has to stay undisturbed for a while...which it won't. You need at least a week of sitting there in the dark...

[double D]

I noticed that the 0z GFS and 0z NAM look very different in the day 4 and 5 time period. Of course the NAM is MUCH cooler than the GFS for Texas. Again the surface features seem not to match the upper flow of the GFS, even in the short term.

[Extremeweatherguy]

Thanks for the response AFM. That was a nice explanation.

BTW, I too was noticing the lack of cold air associated with the high and wondered this: Is it possible for cold air to build under that high before it sinks south? Or is that something that will not happen?

From my own amateur observation, there has seemed to be at least a slight cooling under the high within the last few hours (-16F at Colville Lake in the NW Territory as of 9pm), but I wondered if this could be "real" cooling taking place or just typical temperature variations.

http://www.findlocalweather.com/weather ... anada.html
^^I also am noticing some gradual cooling under the high on this map over the last few hours.^^

There won't be any real cooling under that high. This time of year...especially as the high starts to sink south...you start getting sunlight and plus in order to be a good source region...it has to stay undisturbed for a while...which it won't. You need at least a week of sitting there in the dark...

ok, thanks AFM. Should still be an interesting situation to watch though incase there are any surprises. It looks like your prediction of 27-30 at IAH (which would likely equate to 24-27 where I am) sounds pretty reasonable though at the moment.

[Portastorm]

It's going to be interesting to see whose temp forecasts "bust" this weekend. NWS Fort Worth is predicting a low of 27 degrees Saturday night in Lampasas (about 30 miles northwest of metro Austin), while NWS Austin/San Antonio is predicting a low of 38 degrees in the city that same night.

Meanwhile my brother in Charlotte, NC, is e-mailing me about the snow they're getting this morning .... lucky dogs!

[Dean4Storms]

I just don't see alot of cold air up there either AFM. This looks more like a Canadian cold snap coming moreso than a true Artic Blast. Think all of the east from the plains states eastward will see some cold/dry air, but nothing approaching records.

[double D]

Just watching CNN weather and the met. said that next week that the eastern 2/3 of the country will see the coldest air of the season. He said the source of the cold air (where I did not catch where he said it was) was minus 52 degrees. Is this the extreme cold that JB could have been talking about for next week?

Although I don't see any cold air coming down next week, maybe cool with a slight warming trend later in the week. So I don't know what this guy is talking about as it only like east of the Mississippi will see any real cold.

[Portastorm]

This morning's 0z run of the European shows a stout 1049mb high poised to do -- as AFM likes to say -- the Leeside Slide. I'm going to be watching this with great interest as it would impact us later next week.

http://weather.cod.edu/forecast/ECMWF/e ... mp_168.gif

[wxman57]

Just watching CNN weather and the met. said that next week that the eastern 2/3 of the country will see the coldest air of the season. He said the source of the cold air (where I did not catch where he said it was) was minus 52 degrees. Is this the extreme cold that JB could have been talking about for next week?

Although I don't see any cold air coming down next week, maybe cool with a slight warming trend later in the week. So I don't know what this guy is talking about as it only like east of the Mississippi will see any real cold.

I'm not sure what you're looking at, but take a peek at the day-7 ECMWF for next Wednesday. I don't see a warming trend, just a fairly large pool of cold air sliding straight south lee of the Rockies with a 1054mb high in Canada.



That may be the shot that gets SE TX into the mid 20s next Thu/Fri. But with the general lack of VERY cold air up in Canada, temps below 25 here look unlikely at this point.

[cctxhurricanewatcher]

This morning's 0z run of the European shows a stout 1049mb high poised to do -- as AFM likes to say -- the Leeside Slide. I'm going to be watching this with great interest as it would impact us later next week.

http://weather.cod.edu/forecast/ECMWF/e ... mp_168.gif

Most of the NWS offices in Texas are on board for a warmup next week. JB, in his overnight posts still seems bullish the GFS numbers will bust.

NWS DFW did leave the door open a tad.

Next week at this time someone is going to have some egg on their face..

[wall_cloud]

somebody always has egg on their face. Its the nature of forecasting. If we knew all of the answers, it would be called something else.

[double D]

I was going by the very reliable GFS and CPC outlook. I know the EURO has had a better track record this winter, but lately it too has been showing cold only to change it towards a warmer solution for Texas. I would like to see more consistency before I believe any real cold is headed for Texas.

Wxman 57, is this a case where Houston could be colder than us here in Central Texas? It looks like the 1044 mb high would be east of Austin, but might give Houston some chilly night time lows.

[cctxhurricanewatcher]

somebody always has egg on their face. Its the nature of forecasting. If we knew all of the answers, it would be called something else.

Oh, I know that and it was not meant as a slam. If I were hedging this time around, I think it might be with the NWS offices. This time last week JB was predicting the Arcitc circle setting up shop around the Red River. But who knows?


My bet is if most of you Pro Mets knew all of the anwers, you'd be placing your bets and money on Wall Street or Vegas and not posting with us weather forecaster wanabees.

[double D]

Does this make sense? CPC is calling for much below during the FEB. 3 and 4th timeframe for the Rockies down into the panhandle of Texas, but the graphic just shows normal temperatures...Hmmmm.

http://www.cpc.ncep.noaa.gov/products/predictions/610day/610temp.new.gif

http://www.cpc.ncep.noaa.gov/products/predictions/threats/t_threats.gif

[Air Force Met]

I'm not sure what you're looking at, but take a peek at the day-7 ECMWF for next Wednesday. I don't see a warming trend, just a fairly large pool of cold air sliding straight south lee of the Rockies with a 1054mb high in Canada.

That may be the shot that gets SE TX into the mid 20s next Thu/Fri. But with the general lack of VERY cold air up in Canada, temps below 25 here look unlikely at this point.

Well...I'll have to disagree with that forecast and cause all the others on the board to scream " even the mets don't know what's happening!"

I see a warm up...at least as I define it since I believe temps will get back to normal during the middle of the week...at least from what they are now. I guess that would be defined as a warm up in my book. The 1054 high is also going...in my opinion...to weaken (which on the day 7 is is a 1049) as it moves down the lee-side and spreads out. Because of the almost zonal flow (being forecast by the GFS and EURO at 500mb...they are very close in the upper levels)...I think the high will spread and we will see another cold shot...but not as cold as this weekend. The bulk will go further east than what is already going east this week. Even the 850 temps forecasted in 7 days aren't all that cold in Canada with the next surge. -18C...or 0F ain't that cold for NE ALberta during the first week in Feb. Matter of fact...b/w day 6 and 7 it shows a lot of warming at 850 on the EURO....which could be a result of the zonal pattern and the ridging aloft.

Bottom line for me and temps in the 20's for next week is this: The air in Canada is near normal. Add some modification on to that and a strong zonal flow with the high moving east of us...and I can't see us going almost 15-20 degrees below normal with that setup.

For the rest of y'all...
BTW...for this weekend. The NAM is trending the high further and further east with every run...which means SETX is trending warmer and warmer for the lows. Lesson: Don't jump on those cold NAM temps at the 84 hour point...it likes to trend too cold.

[Air Force Met]

Does this make sense? CPC is calling for much below during the FEB. 3 and 4th timeframe for the Rockies down into the panhandle of Texas, but the graphic just shows normal temperatures...Hmmmm.

http://www.cpc.ncep.noaa.gov/products/predictions/610day/610temp.new.gif

http://www.cpc.ncep.noaa.gov/products/predictions/threats/t_threats.gif

Yes...it makes perfect sense. The 6-10 day oulook is valid from the 6 - 10 Feb. The threat is valid on the 3rd and 4th.