Texas Winter 2014-2015

[Ralph's Weather]

18Z GFS continues showing the same as previous runs. It will be interesting to see when the models start coming to a consensus as they all seem to be holding onto what they were showing all day. Temps in the Panhandle are running up to 10 degrees cooler than modeled so if that trend continues further south then we may have something to talk about.

[Brent]

First time FWD has had accumulation for me:

Thursday Night Cloudy with a chance of rain. A chance of snow after midnight. Very light snow accumulations possible on grass and elevated surfaces. Lows in the mid 30s. Northeast winds 10 to 15 mph becoming north 5 to 10 mph after midnight. Chance of precipitation 40 percent.

[gpsnowman]

Whoa. Just looked at radar and a large rain shield(albeit looking light) is headed this way. Have not had time to check on things until now. Northern Panhandle looks to be getting hammered with snow. I am thinking here in DFW Thursday into Friday, some wet snow will fall not amounting to much. Temps seem to be a tad too warm. Hope it trends down a couple of degrees for some accumulation. Liquid is good either way. Already thinking about spring plans for the yard so every drop, flake, pellet counts.

[Ralph's Weather]

Precip coverage is looking more widespread than modeled and temps over western Texas are cooler than modeled. Now we are entering the short range model range the RAP is showing a band of accumulations from DFW to NE TX under heavy precip. On it surface temps are around 40 with the freezing level around 850mb and the dendritic zone above 600mb. precip would have to be really heavy but I guess it is possible. I would like to see temps overall a couple degrees colder to be more confident.

[gpsnowman]

Precip coverage is looking more widespread than modeled and temps over western Texas are cooler than modeled. Now we are entering the short range model range the RAP is showing a band of accumulations from DFW to NE TX under heavy precip. On it surface temps are around 40 with the freezing level around 850mb and the dendritic zone above 600mb. precip would have to be really heavy but I guess it is possible. I would like to see temps overall a couple degrees colder to be more confident.

Agreed. 40 is too darn high. Might see a large, soggy flake at that temp. Dang it, the temps need to trend way down.

[Ralph's Weather]

Precip coverage is looking more widespread than modeled and temps over western Texas are cooler than modeled. Now we are entering the short range model range the RAP is showing a band of accumulations from DFW to NE TX under heavy precip. On it surface temps are around 40 with the freezing level around 850mb and the dendritic zone above 600mb. precip would have to be really heavy but I guess it is possible. I would like to see temps overall a couple degrees colder to be more confident.

Agreed. 40 is too darn high. Might see a large, soggy flake at that temp. Dang it, the temps need to trend way down.

Steve McCauley just said on FB that temps aloft are 1-1.5C lower than expected increasing snow chances. That may be all we need to get snow down to the surface as that would thin the above freezing level to less than 50mb and keep the air colder for more snowflakes to form, we have tons of moisture to work with aloft so wherever cold enough flakes will form.

[Brent]

In other news...

[aggiecutter]

Shreveport AFD:

"THE FORECAST GETS A BIT MORE TRICKY THURSDAY NIGHT AND ESPECIALLY
FRIDAY MORNING AS THE UPPER TROF AXIS EDGES EVEN CLOSER TO THE
REGION. THIS WILL ENABLE A RAPID COOLING OF OUR ATMOSPHERE FROM
THE TOP DOWN AND ALTHOUGH OUR SFC TEMPERATURES SHOULD REMAIN JUST
ABOVE FREEZING EVEN ALONG THE I-30 CORRIDOR...A WINTRY MIX OF RAIN
AND SNOW LOOKS INCREASINGLY LIKELY GENERALLY ALONG AND NORTH OF A
LINE FROM TYLER TEXAS TO MAGNOLIA ARKANSAS."

[TeamPlayersBlue]

Near the end of the GFS run gets interesting. Looks like the cold wants to return. It brings pretty cold air down but not all the way down. 500 MB chart looks interesting with a full latitude trough.

[BigB0882]

I wonder if any of that snow would make its way to SELA region on the back end? It is 10 days away but a glimmer of hope in this otherwise dull winter for us.

[northjaxpro]

Well Brent, we shall see if the GFS gets this right that far out. If it verifies, Super Bowl Sunday would be a very interesting day across Texas and even into portions of the Deep South. But , this is still 10 days out, so I am sure this will change several times.

Pay closer attention to the runs as we get within 120 hours of this potential event. I would like to let folks know that the GFS within 120 hours showed a scenario of "ocean effect" snow approaching the NE Florida coast. I be darned the GFS ended up being right and light snow indeed made it just far enough inland to give us that surprise!

Just somehting to let those of you who hug the GFS to keep the faith!!

[gboudx]

Interesting update from Steve McCauley regarding temps aloft and sneaux chances:

As Murphy's Law would have it, I have a meeting I have to attend in about an hour, so I am not able to give this forecast the full attention it deserves, but here's the bottom line. As I mentioned in my last post, temperatures ALOFT are forecast (by one computer model) to be about 1 to 1.5 degrees colder than previously expected. I know this does not sound like much, but less than 2 degrees can make a HUGE difference in the type of precipitation that falls this time of year.

The European, Canadian, Texas Tech and one of our American Models are going for ZERO snow in the Metroplex. And of these four models, ONLY THE EURO is going for some light snow accumulations to the north and west of us. For those of you who have been following this page for the last week, you know this has been the Stat Method's forecast all along.

So, if I had only these models to go with, I would not change anything. HOWEVER...one of our MOST sophisticated American Models is going for several inches of snow across much of north Texas, including the Metroplex, with a bull's eye of a nearly a foot of snow in Jack County !!!!! Say what ?!?!

So why is this sophisticated model going for a huge dumping of snow while the others are essentially going for nothing but rain? The answer seems to be that 1 to 1.5 degree temperature difference aloft. The sophisticated, high-resolution computer model is keying in on slightly colder temperatures aloft, something the lower resolution models are not capable of "seeing." That's all it would take to change this cold rain into a heavy blanket of wet snow.

So in the final analysis, we need to PRECISELY forecast what the temperature is going to be about 2,000 feet above our heads. We know this event is going to be a 100% coverage of precipitation, so that's not the difficult part of the forecast. The critical thing to know is what the temperature is going to be 2,000 feet up!

If it is 34 degrees up there by tomorrow, then this will be an ALL RAIN event for us. If it is 32 degrees up there, it will be a heavy, gloppy wet snow. If it is 33 degrees up there, it will be a rain/snow mix.

I will run the Stat Method on this when I get out of my meeting to see if that 2,000 foot temperature is likely to be 32, 33, or 34. Normally, any other time of year, a difference of a couple of degrees at 2,000 feet above our heads would go completely unnoticed by those of us on the ground. But in the winter time, it can make all the difference in the world!

[Ralph's Weather]

Interesting update from Steve McCauley regarding temps aloft and sneaux chances:

This describes exactly what we have been discussing. The RAP and HRRR support validates this idea. It is a very tough forecast and the safe one is all rain, but you cannot ignore the chance of heavy snow.

[Ntxw]

Snow has returned to the great state of Texas...during the thaw...and quite a bit of it in the Panhandle and south plains. As you can see on the radar there is very little pink (ice) this storm is dynamic driven either cold for snow or rain. Keep your fingers crossed for dynamics as the ULL crosses to our south!

HRRR certainly looks interesting indeed as it is picking up on convective features possibly helping the switch. Then watch again as the low itself passes and wrap around moisture tries to move in.



February looks great on the JMA. Cat 5's in the gulf, and blocking a rocking.

[Brent]

Does someone have a link to the HRRR?

I am seriously considering a drive NW... I really don't want to miss this and I'm still unconvinced much happens in DFW, but... I sure hope it does, it would be a lot easier.

[Ntxw]

Does someone have a link to the HRRR?

I am seriously considering a drive NW... I really don't want to miss this and I'm still unconvinced much happens in DFW, but... I sure hope it does, it would be a lot easier.

It can be found on the NCEP model guidance as they incorporated it! It's a lovely tool. Precip type and sim radar is what you're looking for.

http://mag.ncep.noaa.gov/model-guidance ... S&ps=area#

Dr. Ventrice posted this on his twitter. This is a good composite, this is really good we like this. We like this a lot.

[Brent]

It's really breaking out snow just west of Fort Worth around sunrise and still spreading a couple hours later if I can tell where DFW is on a map by now.

[Ntxw]

It's really breaking out snow just west of Fort Worth around sunrise and still spreading a couple hours later if I can tell where DFW is on a map by now.

Yeah with the ULL still out in New Mexico/AZ border. When it crosses is when the atmosphere aloft will be at it's coldest, then depends how much lift it provides for wrap around. Tomorrow night through Friday morning is our best shot.

[Brent]

It's really breaking out snow just west of Fort Worth around sunrise and still spreading a couple hours later if I can tell where DFW is on a map by now.

Yeah with the ULL still out in New Mexico/AZ border. When it crosses is when the atmosphere aloft will be at it's coldest, then depends how much lift it provides for wrap around.

I have fond memories of some ULL's in Alabama. Those things were coined a weatherman's woe by James Spann lol... many surprises over the years.

[opticsguy]

Cool new HRRR page.
http://www.spc.noaa.gov/exper/hrrr/