Texas winter wx thread (2009-2010)

[Portastorm]

FWIW, the 12z NAM looks colder in Texas, especially central and southern Texas, on Friday and Saturday as compared to the 0z NAM.

[double D]

I'm jealous of all the people who saw snow this morning and last night. Maybe the rest of Texas can get in on the action too (fingers crossed).

BTW, I bet the forecaster for DFW NWS feels a little silly after saying earlier in the week that there was not going to be any snow for the DFW area.

[wxgirl69]

FWIW, the 12z NAM looks colder in Texas, especially central and southern Texas, on Friday and Saturday as compared to the 0z NAM.

Does it look like we will have some moisture with that cold?

[Portastorm]

FWIW, the 12z NAM looks colder in Texas, especially central and southern Texas, on Friday and Saturday as compared to the 0z NAM.

Does it look like we will have some moisture with that cold?

Yes indeed!

We gotta watch the 12z GFs now which is running. Am also curious to see what the European run from 12z suggests.

[HockeyTx82]

Here are some picture I took. Sorry about the quality. I took them with my camera phone. I have the HTC Pro 2 with Sprint Make sure and view them full size from the Imageshack site.











It was really cold this morning. I am looking forward to Friday.

[southerngale]

Congratulations to all of you who got snow!! And great pics, everyone. Keep 'em coming.

[iorange55]

GFS 12 looks fairly impressive. I can't believe the consistency in the models from day to day.

[msstateguy83]

i think models could even be under estimating moisture for the upcoming wkend,warms
temps up to quickly after saturday but this has the chance in my opinion to be something big in terms
of some sorta winter storm across a large portion of tx and into ok for thu night -sat iam
fixing to be looking over both the nam/gfs 12z runs...

edit: i do agree nam is trending colder i would put highs sat poss as far s as austin between 34-40
and between 30-34 from okc to dfw... now the only ? is precip and how much

edit 2: no doubt on moisture to the s. iam 70% confident this could be a major winter storm
event for the coastal areas just still questioning up towards northern tx and possibly far
sc ok

[Portastorm]

Regarding the 12z GFS run ... not that I'm overlooking the potential historic wintry weather event here in AUS in two days, but did anyone else notice that 1052 mb high in western Canada on Sunday moving down into the US? Next week we should see possibly an even colder blast of Arctic air!

[iorange55]

Regarding the 12z GFS run ... not that I'm overlooking the potential historic wintry weather event here in AUS in two days, but did anyone else notice that 1052 mb high in western Canada on Sunday moving down into the US? Next week we should see possibly an even colder blast of Arctic air!

Oh yes it's been there the past 2 days or more I believe extremeweatherguy was the first to mention it. It's been as high as 1060, if i remember correctly. The models don't know what to do with it, they've been showing it creepy further, and further south though. Still not anywhere close to what will happen, I'd imagine.

[southerngale]

NWS LCH now has a chance of snow in my forecast for Friday night. I'm trying not to get my hopes up too much, so I'm not crushed if it doesn't happen. lol

But... let it snow! let it snow! let it snow!



However, no accumulation expected. Doesn't the GFS and NAM show accumulation? Perhaps they're just not buying it.

<snippet from early morning NWS LCH AFD>

.LONG TERM...INTERESTING SET UP FOR FRIDAY NIGHT AS CANADIAN AIR
INFILTRATES TODAY AND THURSDAY INTO FRIDAY WHILE ANOTHER COASTAL
LOW DEVELOPS OFF SOUTH TEXAS IN RESPONSE TO THE UPPER LEVEL TROF
OVER WEST TEXAS. THIS TIME THE SURFACE LOW TAKES A MORE SOUTHERN
TRACK ACROSS THE MID GULF ALLOWING ISENTROPIC LIFT OF GULF MOISTURE
INTO PACIFIC MOISTURE UP AND OVER THE CONTINENTAL POLAR AIRMASS IN
PLACE OUT OF CANADA. GFS 1000-500 THICKNESS VALUES FROM 5360M
AROUND JASPER AND LEESVILLE TO 5400M AROUND BEAUMONT AND LAKE
CHARLES ARE SUPPORTIVE OF AT LEAST A MIX OF WINTRY PRECIP FOR
LOWER SE TX AND SW LA...AND ALL SNOW FOR THE LAKES AREA OF
SOUTHEAST TEXAS INTO WESTERN PORTIONS OF CENTRAL LOUISIANA.
AMOUNTS SHOULD BE LIGHT AND DUE TO UNFROZEN GROUND...ACCUMULATIONS
ARE NOT EXPECTED BUT INTERESTING NONE THE LESS.

[msstateguy83]

i saw that, i would go as far as to say this is to stay, any little sign of a 'warm up'
of any drastic measure by models will be in error i do NOT see that happening
at this point the artic door is fixing to be totally open and shooting down loads
of cold air down into the central,southern plains region. i would also expect MULTIPLE
rounds of ICE/SNOW storm events across our area over the next 10-14 days. just using
my knowledge v.s. the models i would also go as far to say ALOT of the region might be
lucky to get above 40 for highs during most of next week... we shall see but this is a def
pattern change that looks to be locked in for awhile =)

[srainhoutx]

Regarding the 12z GFS run ... not that I'm overlooking the potential historic wintry weather event here in AUS in two days, but did anyone else notice that 1052 mb high in western Canada on Sunday moving down into the US? Next week we should see possibly an even colder blast of Arctic air!

Stepping down trend continues.

[Portastorm]

Some interesting, curious thoughts from the mid-morning discussion from forecasters from NWSFO Austin/San Antonio:

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1004 AM CST WED DEC 2 2009

.UPDATE...
UPDATED FORECAST TO DECREASE 1ST PERIOD MAX TEMPS GIVEN COLD AIR
ADVECTION AND TRENDS IN LATEST SURFACE OBSERVATIONS. ALSO DROPPED
MENTION OF RAIN FRIDAY AND WENT WITH ONLY SNOW FOR MOST OF OUR
AREA. THE 12Z NAM12 FORECAST SOUNDINGS SHOW CLASSIC SNOW TRACES FOR
ALL BUT OUR SE COUNTIES...WHERE A MIX OF RAIN AND SNOW IS POSSIBLE
FRIDAY MORNING BEFORE TURNING OVER TO SNOW. HIGH TEMPERATURES ARE
TRICKY FRIDAY...AND WILL LIKELY OCCUR PRIOR TO THE ONSET OF
PRECIP. THE 12Z NAM12 SNOW AMOUNTS ARE SLIGHTLY LESS THAN THE 00Z
RUN...WHICH MATCHES BETTER WITH THE PERCEIVED SNOWFALL POTENTIAL
GIVEN THE EVENT TYPE. WILL WAIT FOR MORE 12Z MODEL DATA BEFORE
CHANGING THE FORECAST SNOW AMOUNTS...BUT THE TREND MAY BE DOWN
FROM THE PREVIOUS FORECAST GIVEN THE 12Z NAM12 OUTPUT.

[iorange55]

Some interesting, curious thoughts from the mid-morning discussion from forecasters from NWSFO Austin/San Antonio:

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1004 AM CST WED DEC 2 2009

.UPDATE...
UPDATED FORECAST TO DECREASE 1ST PERIOD MAX TEMPS GIVEN COLD AIR
ADVECTION AND TRENDS IN LATEST SURFACE OBSERVATIONS. ALSO DROPPED
MENTION OF RAIN FRIDAY AND WENT WITH ONLY SNOW FOR MOST OF OUR
AREA. THE 12Z NAM12 FORECAST SOUNDINGS SHOW CLASSIC SNOW TRACES FOR
ALL BUT OUR SE COUNTIES...WHERE A MIX OF RAIN AND SNOW IS POSSIBLE
FRIDAY MORNING BEFORE TURNING OVER TO SNOW. HIGH TEMPERATURES ARE
TRICKY FRIDAY...AND WILL LIKELY OCCUR PRIOR TO THE ONSET OF
PRECIP. THE 12Z NAM12 SNOW AMOUNTS ARE SLIGHTLY LESS THAN THE 00Z
RUN...WHICH MATCHES BETTER WITH THE PERCEIVED SNOWFALL POTENTIAL
GIVEN THE EVENT TYPE. WILL WAIT FOR MORE 12Z MODEL DATA BEFORE
CHANGING THE FORECAST SNOW AMOUNTS...BUT THE TREND MAY BE DOWN
FROM THE PREVIOUS FORECAST GIVEN THE 12Z NAM12 OUTPUT.

Haha, wow. My friend in San Antonio is going to flip. I wonder what seeing your first snowfall ever when you're in your 20s feels like? I bet it's something you never forget.

[wxgirl69]

GFS 12 looks fairly impressive. I can't believe the consistency in the models from day to day.

What does the blue line stand for and the 1012 number? I think that was the number but, you know what I mean over the Houston area. Thanks..

[TexasSam]

GFS 12 looks fairly impressive. I can't believe the consistency in the models from day to day.

What does the blue line stand for and the 1012 number? I think that was the number but, you know what I mean over the Houston area. Thanks..

that's 0C or freezing, the next one in is -10c

[srainhoutx]

So wxman57, do you think we're looking at a 6-10 hour "event" depending on timing? Or do you expect this to be a quicker hit with precip. Just wondering what your thoughts are at this time.

[joshskeety]

GFS 12 looks fairly impressive. I can't believe the consistency in the models from day to day.

What does the blue line stand for and the 1012 number? I think that was the number but, you know what I mean over the Houston area. Thanks..

That blue line is what we call the 850mb 0 line.. Think of weather as 3d.. Its not just what is happening overhead, there are many layers to the atmosphere.. Some warmer, some colder.. Each layer is measured in MB (Millibars).. 850mb is 5000 feet into the atmosphere.. It is usually the WARMEST above the surface and usually represents anything north of that line is snow, anything south of the line is rain/sleet/ice.. The 0 stands for 0 celcius, which is the freezing point..

For snow to happen it has to be below freezing on EVERY LAYER minus the surface, which can get snow a couple degrees above.. The surface is 1000mb.. From about 975mb up it CANNOT be above freezing, otherwise it will NOT be snow.. But 90% of the time, the warmest temp will be 850mb and that is why they represent it on that map of where that freezing mark is at 5000 feet..

Its never PERFECT, but you can almost bet that if you are North or within that 0c line and there is moisture, it will be snow.. Of course you will never know until you look at a sounding which takes an area and looks at the temp of each layer of the atmosphere..

Hope this helps!

Josh

[ColdFusion]

That map looks like the precip line for Friday just clips the Dallas area. Cold will be there, but will the moisture make it far enough north? - that will be the big thing to watch over the next 48 hours. Cmon, please, a snow day on a friday makes for a nice 3 day weekend.