Texas Winter 2014-2015

[Portastorm]

Personal attacks on any member here ... especially our gracious professional meteorologists ... will not be tolerated.

Let's get back to the discussion on our "winter" weather.

[BigB0882]

Could you explain what this map is showing? I have never learned how to read these "yellow maps" as I call them. lol

[weatherdude1108]

Could you explain what this map is showing? I have never learned how to read these "yellow maps" as I call them. lol

I have trouble reading those maps too.

[TexasStorm]

Anyone know how many freezes we have had this winter compared to this time last year? I googled it but not able to find that information anywhere.

You may have to extract the data yourself to figure it out. If you go to this page: http://www.srh.noaa.gov/fwd/?n=dfwclimo you can use the drop-down "Daily Summaries for Previous Months". The data is there for you to extract <= 32. Have fun!

Thanks! Below is what I came up with. So this time last year we had a total of 39 freezes in DFW. This year we have 20 through January.

October 2013 - 0
November 2013 - 5
December 2013 - 19
January 2014 - 15
February 2014 - 12
March 2014 - 4
April 2014 - 0


October 2014 - 0
November 2014 - 6
December 2014 - 4
January 2015 - 10
February 2015 - ?
March 2015 - ?
April 2015 - ?

[srainhoutx]

The GFS, NAEFS and GEFS are suggesting a very deep Central and Eastern trough developing around the 10th of February. There is a storm system diving S out of Western Canada with additional energy developing into the 4 Corners Region. Those 500mb charts suggest a very deep upper low entrenched across the Upper Mid West/Great Lakes with a robust cross Polar flow developing. Still way out in computer model world for any certainty regarding what the sensible weather may actually be mid February, but those charts are not warm temperature wise for Texas.

[Texas Snowman]

And here comes the rebuttal - wait for it - in five, four, three, two, one...

[Texas Snowman]

http://s16.postimg.org/bjmvt06n9/2015_0 ... _34_pm.png

Could you explain what this map is showing? I have never learned how to read these "yellow maps" as I call them. lol

A fairly north to south flow out of Canada - even a Canada that isn't as cold as we'd like - right on down the Plains into Texas? My guess is that even for a day or so, this isn't the kind of map a certain bicycle rider in Houston would like!

[dhweather]

In short, the Polar Vortex has moved extremely far South and set up over the midwest US (Indiana/Michigan/Ohio). IF this were to happen, it would likely be sustained bitterly cold east of the Rockies. Cold is the #1 ingredient required for wintry precip - so that's important for anyone wanting wintry precip.

The map as a whole depicts the large scale pattern at 500 millibars in height (18-20,000 feet) and gives you a good idea of where troughs and ridges are. The yellow part - that is for the vorticity. Basically, vorticity is the flow of the air, clockwise (high pressure) or counter-clockwise (low pressure). When you start seeing colors (usually yellow) that is indicative of a stronger flow around the feature. In the map above, off the west coast, there is a pretty strong trough, it goes past yellow into orange (see the scale on the left side of the chart). The "polar vortex" features a lot of vorticity on the southern side, which is typically the case on counter clockwise flow.

In this map, there's a ridge over the west coast, so the air flow goes up into Canada and the Rockies, then comes back down into the plains. Note some of the black lines the depict this. Just above them, you will see some black lines (isobars) that appear to indicate the possibility of a cross-polar flow (follow those black lines at the top center of the image down into the plains on the west side of the "polar vortex")

The other key ingredient for wintry precip is moisture, and with a strong northwest flow, that will be nearly impossible for us to get, which makes this so sad, a tragic waste of cold air. IF IT HAPPENS - remember, that's 384 hours out, and very likely not going to happen.

[Texas Snowman]

At least there's no Cat 5 in the Gulf at that point!

[dhweather]

I forget who told NTXW, maybe he will weigh in here, "follow the vorticity" - usually you will have a pretty decent chance at wintry precip if the yellow/orange is over you. I think it was the Christmas Day storm a few years ago, the vorticity maximum went right over north Texas, which gave us the mechanisms we needed to get the precip. I remember NTXW saying (fill in the blank) always said to follow the vorticity.

[Ntxw]

Models busted on temperatures today, as many posted this morning's was off by nearly all guidance and today's high is struggling around 40.

[Texas Snowman]

Models busted on temperatures today, as many posted this morning's was off by nearly all guidance and today's high is struggling around 40.

Bust on temperatures you say?!? Pshaw!!! We only made it down to a low of 22 this morning, then rebounded all the way up to a high of 40 this afternoon under bright and sunny skies.

All in all, a great Groundhog's Day for a little bit of bike riding here in Texomaland!

But if that seems a little cool for you, well then, never fear. Because I'm SURE that all of the warm February weather talked about the last few days - you know, with all of those trustworthy model runs - will verify.

Just like today's temperatures did.

[Ntxw]

I forget who told NTXW, maybe he will weigh in here, "follow the vorticity" - usually you will have a pretty decent chance at wintry precip if the yellow/orange is over you. I think it was the Christmas Day storm a few years ago, the vorticity maximum went right over north Texas, which gave us the mechanisms we needed to get the precip. I remember NTXW saying (fill in the blank) always said to follow the vorticity.

It was Air Force Met, he/she used to post more often. FW made a post discussion after the storm and dubbed it "systems like this will find moisture." It was during the Superbowl snowstorm that I picked this up from. Models seemingly showed no moisture for North Texas instead showing SE Texas. And really there wasn't, but the yellows, oranges, and reds on those maps are vorticity, areas of stronger winds. That provides lift and lift squeezes out whatever is in the atmosphere. The same kind of occurrence happened last February during the snow event we had. This is how arid places such as the northern plains (Dakotas) can squeeze out so much snow being so far from water bodies. PV anomalies (vorticity) in many cases is stronger the more poleward you go.

[Texas Snowman]

Thanks for shedding light on that. I've always wondered how places like Montana, North Dakota and South Dakota can sometimes pick up so much in the way of snowfall being so far away from moisture sources.

I'm a sincere winter weather enthusiast and I've picked up some knowledge over the years that I've spent here. But few days go by that I don't look at the posts here and feel that compared to most of you folks on this forum, I'm a bit clueless. I'm afraid that I rarely have anything meaningful to contribute to the conversation other than "Go get them team!"

[amawea]

:uarrow: Thanks for shedding light on that. I've always wondered how places like Montana, North Dakota and South Dakota can sometimes pick up so much in the way of snowfall being so far away from moisture sources.

I'm a sincere winter weather enthusiast and I've picked up some knowledge over the years that I've spent here. But few days go by that I don't look at the posts here and feel that compared to most of you folks on this forum, I'm a bit clueless. I'm afraid that I rarely have anything meaningful to contribute to the conversation other than "Go get them team!"

I am in your category 100% Texas Snowman. I have been a weather fanatic since I was 10 years old reading everything I could get my hands on. I have come to know that I know very little these days. I am in my 60's and the world of weather forecasting has passed me by.

[TeamPlayersBlue]

:uarrow: Thanks for shedding light on that. I've always wondered how places like Montana, North Dakota and South Dakota can sometimes pick up so much in the way of snowfall being so far away from moisture sources.

I'm a sincere winter weather enthusiast and I've picked up some knowledge over the years that I've spent here. But few days go by that I don't look at the posts here and feel that compared to most of you folks on this forum, I'm a bit clueless. I'm afraid that I rarely have anything meaningful to contribute to the conversation other than "Go get them team!"

I could be partly wrong but, air molecules have a dewpoint temp or a temp where the molecule will turn into water. This is for every molecule. Now, while air molecules in these regions may be drier than say around the GOM or the pacific, If these molecules encounter an area where there is alot of rising air where the molecule cools to the point where it becomes a droplet and voila!

Basically, its the rising air which is responsible for creating moisture in the atmosphere in areas where there isnt a body of water etc

[Ralph's Weather]

Already down to 30 here, we will see how far it falls before warm air advection stops the cooling. Today was a refreshingly cool day with bright sun. I will be watching to see how much moisture is available with this week's storm, hopefully we can get some rain since we did nor get much this weekend. l have not 100% ruled out winter mischief this week but it is doubtful.

[wxman57]

I'm still not seeing anything in the GFS or ECMWF that indicates a major change in the flow pattern across the Gulf of Alaska and NW Canada. The low over the Gulf of Alaska is forecast to continue pumping relatively warm Pacific air into western Canada through 10 days on the Euro and through 15 days on the GFS. The GFS does indicate a deeper Polar low over the Great Lakes by the 18th (see below) but look at the flow through western Canada - warm. Some cold air should make it south to Texas from this vortex, but nothing more than a possible light freeze is indicated across NE and SE TX under that pattern. It's not a snow pattern for Texas, that's for sure.

Note, I drew red arrows on the 500mb (18,000 ft up) maps to indicate general air flow for those less familiar with how to read the maps. I also indicated the predicted high and low centers (again, at 18,000 ft up).





GFS 2m Surface temperature anomalies (below). Note the quite warm (compared to normal) temps all across western Canada. We need that area to be cold to get really cold in Texas, and to have a chance of snow outside of the Panhandle.

[wxman57]

From Jeff Lindner (of Harris County Flood Control District) this morning.

Turning Much Warmer

An upper level storm system over Mexico will cross southern TX today.

At the surface a dry low level air mass is in place with dewpoints in the 20’s and 30’s and temperatures in the 30’s and 40’s with light ENE winds. An upper level storm system over Mexico will move across S TX and into the Gulf of Mexico Wednesday. Mid and high level clouds area already in place with a fair amount of reflectivity showing on local radars. Much of what is showing on the radar is not reaching the ground per surface observations and this is due to a very dry sub cloud layer resulting in extensive evaporation.

Air mass especially south of I-10 should gradually moisten today with an increasing amount of rainfall reaching the ground by mid to late afternoon into the evening hours. Expect the heaviest rainfall to remain offshore over the Gulf waters near the track of an offshore surface low. Rainfall amounts will average .25 to .50 of an inch south of US 59 to less than .25 of an inch north of I-10. Temperatures will struggle to reach 50 today under clouds and light rain.

Upper storm system clears eastward Wednesday afternoon after morning showers and expect a return of sun and warming trend Thursday-the weekend. Lows will warm into the 40’s and 50’s by Saturday under increasingly southerly flow with highs pushing the mid 70’s Saturday and nearly 80 on Sunday. Looking to be another stretch of mild and rain free weather Thursday-early next week.

[Tireman4]

From Jeff Lindner (of Harris County Flood Control District) this morning.

Turning Much Warmer

An upper level storm system over Mexico will cross southern TX today.

At the surface a dry low level air mass is in place with dewpoints in the 20’s and 30’s and temperatures in the 30’s and 40’s with light ENE winds. An upper level storm system over Mexico will move across S TX and into the Gulf of Mexico Wednesday. Mid and high level clouds area already in place with a fair amount of reflectivity showing on local radars. Much of what is showing on the radar is not reaching the ground per surface observations and this is due to a very dry sub cloud layer resulting in extensive evaporation.

Air mass especially south of I-10 should gradually moisten today with an increasing amount of rainfall reaching the ground by mid to late afternoon into the evening hours. Expect the heaviest rainfall to remain offshore over the Gulf waters near the track of an offshore surface low. Rainfall amounts will average .25 to .50 of an inch south of US 59 to less than .25 of an inch north of I-10. Temperatures will struggle to reach 50 today under clouds and light rain.

Upper storm system clears eastward Wednesday afternoon after morning showers and expect a return of sun and warming trend Thursday-the weekend. Lows will warm into the 40’s and 50’s by Saturday under increasingly southerly flow with [b]highs pushing the mid 70’s Saturday and nearly 80 on Sunday. Looking to be another stretch of mild and rain free weather Thursday-early next week.

[/b]


I guess it is time to move to Alaska...sigh...