The Official Texas Snow Thread...

[gboudx]

Earlier this week, the forecast for Monday night/Tuesday was for at least a 20% chance of snow with a high on Tuesday below 32. Now, it's different. Okay, so they didn't shutdown the idea of snow. But it certainly has been scaled back.

[Extremeweatherguy]

SATURDAY PRECIP LOOKS LIKE ALL RAIN SOUTH OF I-20

I believe this is talking about RAIN if you read the whole sentence:

BY MID MORNING NORTHERN HALF IS WARM ENOUGH FOR RAIN
ONLY. ONCE AGAIN...AMOUNTS WILL BE VERY LIGHT ACROSS MOST OF NORTH TEXAS...WITH ONLY THE FAR SOUTH AND SOUTHEAST HAVING A CHANCE OF DECENT ACCUMULATIONS.

And when it is cold enough:
HOWEVER...MOISTURE IS VERY LIMITED SO ONLY SLIGHT CHANCE IN
THE ZONES FOR MONDAY AND TUESDAY EXCEPT IN THE WEST AND SOUTH WHERE WE HAVE A LOW CHANCE.

Doesn't sound promising to me at all.

When they say "except in the west and south there will be a low chance" (low would be 20-30% compared to the "Slight chance" further north which is 10-20%)...means that there will be a higher chance of snow in the west and southwest areas of the DFW forecast area. What does that mean? Well south would mean closer to Houston. Obviously they think the moisture will be south and that is way Waco has a forecast of flurries for Monday night and rain and snow on Tuesday. I think the moisture will be there regarding SE Texas...it is just the temperatures and timing of the moisture that will need to be watched. BTW Dallas is still forecasting a 20% chance of snow for the metro area on Monday night and Tuesday. There is still lots to watch, and I am not saying "We will have snow", but I am just saying that the chance is still there, and it has not been taken out of the forecast.

[gboudx]

They just updated that forecast because the 20% wasn't there earlier this morning. Coincidentally, they put out an AFD update at 10:42am. Who knows? I'll just wait until Friday night and Tuesday and see if snow is falling.

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE FORT WORTH TX
1042 AM CST THU DEC 15 2005

.UPDATE...
NORTHWEST SURFACE FLOW WITH VERY DRY AIR FILTERING INTO THE NORTHERN
CWA TODAY. DECIDED WINDS WILL NOT BE STRONG ENOUGH FOR RED FLAG
CONDITIONS THIS AFTERNOON.

NEW MODEL RUNS JUST ARRIVED IN HOUSE. QUICK LOOK AND FIRST GUESS IS
THAT THE ATMOSPHERE WILL BE COLD ENOUGH INITIALLY LATE FRIDAY NIGHT
FOR A LITTLE SNOW MIXED IN WITH THE RAIN NORTH OF I-20...BUT THE
MODEL SOUNDING WARMS ABOVE FREEZING BY MID MORNING SATURDAY. THUS I
WILL NOT CHANGE THE FRIDAY-SATURDAY FORECAST AT THIS TIME.

AS FOR EARLY NEXT WEEK...CURRENT THINKING IS THAT THIS WILL BE A
TEXAS COASTAL SYSTEM WITH THE SOUTHERN AREAS OF OUR CWA BEING
FAVORED FOR A GOOD WETTING AND SOME WINTRY PRECIPITATION BY TUESDAY
NIGHT. AS FOR THE NORTHERN COUNTIES....GENERALLY LIGHT PRECIPITATION
TUESDAY.

WILL NOT CHANGE CURRENT FORECAST RIGHT NOW. WILL CONTINUE TO
EVALUATE THE WINTRY THREAT.

[jasons2k]

SATURDAY PRECIP LOOKS LIKE ALL RAIN SOUTH OF I-20

I believe this is talking about RAIN if you read the whole sentence:

BY MID MORNING NORTHERN HALF IS WARM ENOUGH FOR RAIN
ONLY. ONCE AGAIN...AMOUNTS WILL BE VERY LIGHT ACROSS MOST OF NORTH TEXAS...WITH ONLY THE FAR SOUTH AND SOUTHEAST HAVING A CHANCE OF DECENT ACCUMULATIONS.

And when it is cold enough:
HOWEVER...MOISTURE IS VERY LIMITED SO ONLY SLIGHT CHANCE IN
THE ZONES FOR MONDAY AND TUESDAY EXCEPT IN THE WEST AND SOUTH WHERE WE HAVE A LOW CHANCE.

Doesn't sound promising to me at all.

When they say "except in the west and south there will be a low chance" (low would be 20-30% compared to the "Slight chance" further north which is 10-20%)...means that there will be a higher chance of snow in the west and southwest areas of the DFW forecast area. What does that mean? Well south would mean closer to Houston. Obviously they think the moisture will be south and that is way Waco has a forecast of flurries for Monday night and rain and snow on Tuesday. I think the moisture will be there regarding SE Texas...it is just the temperatures and timing of the moisture that will need to be watched. BTW Dallas is still forecasting a 20% chance of snow for the metro area on Monday night and Tuesday. There is still lots to watch, and I am not saying "We will have snow", but I am just saying that the chance is still there, and it has not been taken out of the forecast.

Well, duh........I have lived in Texas since 1988, most of that in the DFW area, (except a 1 year stint in Alabama from 1992-1993)....so I know my Texas Geography

Yes, this will be a coastal system with more moisture available in the HGX zones. But I don't think it will even come down to a timing issue, Metro Houston will have a hard time reaching the freezing mark at all, even after the precip is long gone.

I'm not trying to rain on your parade although it may sound like it. I'm just saying I've been watching Texas winter events materialize (or rather, unravel) for almost 20 years now and if you think this is the system to bring your Houston snowstorm you might as well accept it now, it's not gonna happen. Sorry to disappoint you but I don't control the weather, just telling it like it is. Look for nothing more than a cold miserable rain unless you want to take a road trip.

[Brent]

12z GFS... no snow anywhere in Texas next week. There's precip for the coast, but it's way too warm.

[ETXHAMXYL]

JINXED!!! Everytime the Local Mets say the "S" word it doesn't happen. I think I'd rather them say No Way for Snow in the beginning and then watch them have to eat their words later when there is 2-4" of snow on the ground.
So we have been JINXED since they have since the beginning called for the "S" word days ago.

[PTrackerLA]

12z GFS... no snow anywhere in Texas next week. There's precip for the coast, but it's way too warm.

Rats!

[Air Force Met]

When they say "except in the west and south there will be a low chance" (low would be 20-30% compared to the "Slight chance" further north which is 10-20%)...means that there will be a higher chance of snow in the west and southwest areas of the DFW forecast area. What does that mean? Well south would mean closer to Houston. Obviously they think the moisture will be south and that is way Waco has a forecast of flurries for Monday night and rain and snow on Tuesday. I think the moisture will be there regarding SE Texas...it is just the temperatures and timing of the moisture that will need to be watched. BTW Dallas is still forecasting a 20% chance of snow for the metro area on Monday night and Tuesday. There is still lots to watch, and I am not saying "We will have snow", but I am just saying that the chance is still there, and it has not been taken out of the forecast.

This is what I was talking about yesterday...you are trying to forecast an event with your heart and not your head

BTW...take a look at the 12Z GFS. Whereas 543 thickness values were abround houston when there was precip...now on the new run they are about 549. 850mb temps over HOU are about 4-5C up from 1C at 06Z, and up to 5C at 12Z...up from 0C.

That's a lot of warming.

[Extremeweatherguy]

Ok as of right now I will back off a little on my snow idea and accept that it may only be a cold rain in Houston . Hopefully we do get some sort of winter weather before the winter is done though; and may be, just may be something will still happen with this system. Who knows...strange things happen all the time.

[Johnny]

It seems to me that models do not handle wintery events in Texas at least that well at all. Sure they will hint at it, then lose it, then maybe hint at it again but shoot...their is no consistency. I'd throw the models out as of now. We really won't know for sure until the event arrives.

[Air Force Met]

It seems to me that models do not handle wintery events in Texas at least that well at all. Sure they will hint at it, then lose it, then maybe hint at it again but shoot...their is no consistency. I'd throw the models out as of now. We really won't know for sure until the event arrives.

What they tend to do is cool it down too much...that's why they forecast far more events than actually happen. The one thing about this event that stuck out to me is we really didn't have a powerful high sliding down. The upper low coming across was perfect in it's timing...but the air wasn't cold enough. I read many times the GFS is too warm is some locations. In SETX it is the case a lot of times it is too cold. You have to remember a couple of things when forecasting snow here. First...it's rarely below freezing. Period. That warm earth we get down here goes out as longwave radiation and is hard to cool. When we do get an airmass cold enough to get us below freezing...because of all that stored up longwave radiation...it's usually too dry.

[Johnny]

Gotcha....with the event last year if I recall, it wasn't a big blast of cold air at all. I believe it was an arctic front but very short lived....kind of like last weeks front. I live in central Montgomery County and we got up to 38 degrees on Christmas Eve day but it was colder to the south of us? I remember the cold didn't stick around that long at all. Is this the kind of cold that is coming next week?

[Air Force Met]

OK…analysis from the 12Z run…this of course is just for fun since it’s pretty plain to see what happened by just looking at the NCEP charts. But then again maybe not.

21/00Z – 21/12Z The changes in the model are two-fold throughout the period. The first part makes sense…the second part doesn’t.

Part one. The temps throughout the column increase. Temps are above freezing from 6000’ at Waco to near 9000’ at GLS. B/W 03-09Z there is a cold layer of near freezing to below freezing from about 1000’ to about 3000’ from near ACT to IAH.

Part Two. Now here’s the part that doesn’t make any sense. The model puts a lot more precip down. However, RH values are lower than the 00Z run. Vertical velocities are higher…but RH’s…especially 2000=6000’ are a lot lower…in some cases below 60%. This makes no sense given heavy precip on the south side especially. The RH’s should be over 90% but they are not.

I’ll run it again later to make sure all the data is in...like the RH values…but something doesn’t makes sense on this run. What I would expect to happen is the RH’s to rise and the freezing level to lower to near 3000’-5000’. Like I said…I’ll give it an hour or two and re-run it to ensure all the data got in.

[Air Force Met]

Gotcha....with the event last year if I recall, it wasn't a big blast of cold air at all. I believe it was an arctic front but very short lived....kind of like last weeks front. I live in central Montgomery County and we got up to 38 degrees on Christmas Eve day but it was colder to the south of us? I remember the cold didn't stick around that long at all. Is this the kind of cold that is coming next week?

Kinda...but a little warmer. What happened to make it colder south of you was evaporative cooling. The air was dry. The dewpoint was in the low 20's that afternoon. That's one reason I was calling for snow. Even though the temps were above freezing...I knew we would get precip and once it started and with a temp in the mid-30's...the dewpoint would rise and the temp would fall...probaby meeting in the upper 20's...which is perfect snow temp....good for nice big flakes.

The reason it was warmer to the north was there was less precip...so less evaporative cooling.

[Johnny]

Good explanation.

With your latest analysis what I want to know is in your opinion AFM...whee is JB getting his 1983 and 1989 ideas from with this next shot of cold air? I don't read his column so I don't know if he still stands behind this? From what you are saying, it will get nowhere even close to that. I know that you said that he has a hard time bailing out of a forecast but this would make him look pretty darn rediculous.

[Extremeweatherguy]

It seems like JB has backed off somewhat from these earlier ideas, but it seems like he still sees a shot at some interesting weather down here in Texas. I will have more after I read his latest post which usually comes out between now and 6pm.

[Air Force Met]

Good explanation.

With your latest analysis what I want to know is in your opinion AFM...whee is JB getting his 1983 and 1989 ideas from with this next shot of cold air? I don't read his column so I don't know if he still stands behind this? From what you are saying, it will get nowhere even close to that. I know that you said that he has a hard time bailing out of a forecast but this would make him look pretty darn rediculous.

I think what you will see is him not mention much more about Texas snow. That's usually how he bails...he just stops mentioning it. So...whereas two days ago it was ice down to I-10...now he probably will just not mention it.

One thing I also want to do is compair the 00Z run and the 12Z run. There are some big diffs. I'll do it on the other thread (model analysis).

As far as where he is seeing it...I'm not sure. It was more of a pattern recognition than something that was tangible to grab. He pumped the Euro until it backed off...then he stopped talking about the Euro.

[aggiecutter]

Air Force Met, are you trying to say that JB is prone to a little hyperbole.

[Johnny]

Thanks extremeweatherguy.


A couple more questions. Let me know if I'm wrong. Usually when very cold arctic air settles into Texas, it comes from Alaska. I'm guessing both in 1983 and in 1989 the cold air came out of Alaska and not northern Canada? As of now Alaska's temperatures are not that cold at all. The region that is holding the very cold air is in the northern region of Canada where temperatures are running anywhere from -17 to -38. It's a given that this is where JB is getting his cold bias from but doesn't bitter cold air in northern Canada usually veer off to the east once it enters the CONUS? Have we ever had a strong arctic front push through the entire state of Texas where the cold air came from northern Canada where the bitterly cold temperatures currently are?


http://www.weatherunderground.com/globa ... ature.html

[Extremeweatherguy]

This is weird. The accuweather.com forecast for Spring, Texas now calls for 42 next Tuesday with rain and then 34 next Tuesday night with a mix of rain and snow. Now I am not saying that I am going to start yelling "snow!" again...but this is a pretty cool forecast for being just 5 days out. Now only if it were to verify... ahhh that would be nice.