Texas Winter 2010-2011

[txagwxman]

Interesting 18z GFS...freezing rain East Texas on Wednesday...I just looked at the profiles.

Going to be another interesting week---get some sleep!

[johnbasham]

Interesting 18z GFS...freezing rain East Texas on Wednesday...I just looked at the profiles.

Going to be another interesting week---get some sleep!

I was just looking at the same thing. That along with the North Texas temperature profile for Sunday's precip is all over the road (little agreement).

But, as with you I am more interested in the Wednesday event. Interesting set up.

[iorange55]

Nice graphic by the NWS in Brownsville...WOW

So I was getting all my snow from Joe Pool Lake! I knew it.

[Tejas89]

DFW down to 23. I wonder if the 16 low tomorrow a.m. is a little too conservative.

[srainhoutx]

Interesting 18z GFS...freezing rain East Texas on Wednesday...I just looked at the profiles.

Going to be another interesting week---get some sleep!

Yet stalls the front magically N of Houston...

[southerngale]

I know it's early, but just about every weather expert, met I've seen, seems to be convinced we'll (TX) see snow/mix middle of next week. Of course the usual suspects is NTX and Oklahoma (storm would be a little bit more south than the big storm earlier this week). And for Southerngale, potential for something to track yet again!

I ain't falling for it again!

[txagwxman]

Interesting 18z GFS...freezing rain East Texas on Wednesday...I just looked at the profiles.

Going to be another interesting week---get some sleep!

I was just looking at the same thing. That along with the North Texas temperature profile for Sunday's precip is all over the road (little agreement).

But, as with you I am more interested in the Wednesday event. Interesting set up.

Crazy weather...but it should end next weekend for a while.

[BrokenGlass]

Question for the Pro Mets...

Why does the FTW AFD go with a "blended solution"? If the GFS and Euro are saying 2 different things, why not do some analysis and pick a solution to trust, rather than formulating a "guess" based upon features from disagreeing solutions? Why not pick a horse and go with it?

[Texas Snowman]

Finally stopped snowing in Denison about an hour or so ago.

Had a good burst of snow overnight into the morning hours, then some more early this afternoon, and then a final burst late afternoon when it really came down hard for a while.

Roads are totally snowpacked tonight and treacherous once again although Hwy. 75 did get plowed.

All in all, seems like a solid 3-5 inch snowfall in Grayson County.

What a memorable Super Bowl week this has been.

BTW, by my count, we've now had a seasonal snowfall of 12 inches in my backyard so far this winter. And we've had solid snowcover for nine complete days.

[txagwxman]

Question for the Pro Mets...

Why does the FTW AFD go with a "blended solution"? If the GFS and Euro are saying 2 different things, why not do some analysis and pick a solution to trust, rather than formulating a "guess" based upon features from disagreeing solutions? Why not pick a horse and go with it?

The analysis is probably almost identical.

[Air Force Met]

Crazy weather...but it should end next weekend for a while.

I've got lots of lessons learned for this past event. I am putting a bust review together and will be glad to share when its completed.

I already know where the forecast when wrong...and looking via hind site...it was very obvious that SE TX would see a freezing rain event...even with the available guidance.

BASICALLY: I saw the negatives...and dis-regarded them because the models themselves were putting down snow. The GFS/NAM/Euro/GEM were all putting out snow depths of varying degrees. I falsely assumed (and that is because I don't know how the models do the calculating) that the "snow" parameters were built into the models and that THEY would QC themselves...and if certain parameters were not met...then they wouldn't put a 1" snow depth over an area. I assumed the model would know the critical thicknesses. That's why when I noticed that critical temps and critical thicknesses were not being met...I assumed I wasn't reading something right.

Well...I was reading it right and the model was ignoring it. That makes it even more frustrating. It's one thing to blow a forecast because you didn't see something. Its another thing to blow it when you know what the rules of thumb are saying...and you ignore them because the model said something different. THAT'S being a model reader and I've always hated it when forecasters do that (since so many today have lost the true skills of forecasting and instead read the models).

Another critical value that I saw lacking...spoke about it here and talked at length to Jeff about it on Tuesday/Wednesday (and with several other mets as well) was the -8C critical temp rule of thumb. That rule says "If you have a melting layer, then the temp of the cold layer below MUST be -8C somewhere in the column. If not, freezing rain is the result."

None of the models showed that -8C mark at anything below 600MB...and above 500-600mb...it was dry...so no snow being made there. THEN...even when it was moist...the melting layer at 850-700 was thick enough to melt the snow above it...and there was no -8C below it...so it fell as sleet and freezing rain. If the snow melts...you must reach -8C for it to re-freeze into snow. If not...it remains super-cooled and liquid until it reaches the ground...or it turns to sleet.

So yes...a very frustrating forecast...especially given that temps were never below -8C...and the critical thicknesses of 1000-500, 850-500, and 700-500 (the last two are VERY important if you have a warm layer...which we did) were all above the threshold. And in this instance...the last 2 were spot on if you took a blend of them. ALSO...using the partial thickness table...the Rules state...if you have a 1000-850 thickness of 129-131 DM...and a 850-700 thickness of >154 DM, you should expect "Freezing rain, with sleet near 154DM on the 850-700."

At 06z, Houston had thicknesses of 129 and 155. So...freezing rain mixed with sleet...
At 12Z...127 and 154. That rules states: "Freezing rain/freezing drizzle and sleet" with weak upper level forcing and little/no CAA at the surface.

I will have more in my bust review...but the best thickness values for this event (due to the warm layer) was the 850-500 thickness. It was almost spot on...

[Tejas89]

It's 43 in Calgary, and 23 in Dallas. What is wrong with this picture?

[SaskatchewanScreamer]

shhhhhh we are enjoying it up here right now!

[wall_cloud]

Question for the Pro Mets...

Why does the FTW AFD go with a "blended solution"? If the GFS and Euro are saying 2 different things, why not do some analysis and pick a solution to trust, rather than formulating a "guess" based upon features from disagreeing solutions? Why not pick a horse and go with it?

While the blended forecast usually turns out to be a not so good forecast, its a starting point from which to work. Follow the a cold solution and the front is slow, your forecast can be off 40 degrees. They are waiting for better consistence/handling of the pattern. Its not a WFO FWD issue, that is pretty standard operations.

[jasons2k]

Air Force Met - thank you so much for your open and honest analysis of why we saw the freezing rain event.

Folks - this is a lesson from one of the masters

One more round and then I'm ready for spring!!

[jasons2k]

Already down to 26 here - wow. At least the dew point is 24F now, so hopefully it won't get too cold.

[wall_cloud]

Nice graphic by the NWS in Brownsville...WOW

Can you substantiate that the feature was a snowband and not an orographic low cloud or snow?

I'm not saying that it isn't because these mesoscale features can occur anywhere. However, that band doesn't appear to be in the right location. That appears to be an AWIPS image but its hard to trust a source that talks of an unsual "phemonenon".

[gboudx]

Can you substantiate that the feature was a snowband and not an orographic low cloud or snow?

I'm not saying that it isn't because these mesoscale features can occur anywhere. However, that band doesn't appear to be in the right location. That appears to be an AWIPS image but its hard to trust a source that talks of an unsual "phemonenon".

The image is found in a product from the Brownsville NWS office. If you have any contacts down there, maybe ask them some details about this phenomenon because they only show the graphic but don't provide discussion.

http://www.srh.noaa.gov/images/bro/news ... ruary4.pdf

[Rgv20]

Nice graphic by the NWS in Brownsville...WOW

Can you substantiate that the feature was a snowband and not an orographic low cloud or snow?

I'm not saying that it isn't because these mesoscale features can occur anywhere. However, that band doesn't appear to be in the right location. That appears to be an AWIPS image but its hard to trust a source that talks of an unsual "phemonenon".

The only substantial snow fall reported in Starr county was in Salineno so I believe its showing snow in that image and everything inside the blue line there was reports of snow.

If that makes any sense..lol

[opticsguy]

lake effect mesoscale vortex
http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2007/01/070130_kgrb_vis_ir4_ir2_14.jpg