November Weather Discussion. Rollercoaster Pattern.

[TexasMetBlake]

I was actually surprised to learn that snow in Dallas in November has happened before...several times in fact. I think the earliest snowfall on record is November 13th, 1979 when they picked up over 4". The next time was in late November (forgot the year) when they picked up 5.7". So IF** and ONLY IF** this were to come to fruition, it would not be TOTALLY unheard of.

[Ptarmigan]

Yeah, I've been a bit surprised how 'Nino' the pattern looks. It will be interesting to see just how well the GFS handles the pattern since the upgrade, early this summer. IF the trends continue, Thanksgiving around TX/OK could be a real treat.

The upcoming pattern definitely looks like an El Nino November for us, fo sho...

Looks to be an interesting weather event. Not all La Ninas are going to be warm and dry, like the Winter of 2000-2001. December 2000 is the 3rd coolest December after 1989 and 1983.

Top 10
Coolest
44.4 1989
45.7 1983
47.6 2000
48.6 1914
49.2 1976
49.4 1963
49.4 1909
49.4 1898
50.1 1997
50.1 1925

http://www.srh.noaa.gov/hgx/?n=climate_iah_top10_dec

It shows that La Nina is not the sole reason for winter, though it plays a huge role. Also, there is Arctic Oscillation, North Atlantic Oscillation, Pacific-North America Teleconnection, Pacific Decadal Oscillation, etc.

[sambucol]

What are the temps looking like for the Houston area with the next cold front and Thanksgiving?

[TexasMetBlake]

The 18z is not nearly as amplified with the trough, but still shows significant cooling behind the front with most of the precipitation ending before it gets cold enough to snow. Any left over moisture may mix and or change to snow in Dallas but it remains to be seen. Situations like this aren't handled well with the models. This will be a day by day thing.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _216.shtml

[srainhoutx]

What are the temps looking like for the Houston area with the next cold front and Thanksgiving?

I suspect that we'll see temps similar to this past weekend for next. Thanksgiving? A bit too far out to know with any certainty, but guidance suggests a very chilly pattern across the Southern Plains, for what it's worth.

[Mr. T]

Looks to be an interesting weather event. Not all La Ninas are going to be warm and dry, like the Winter of 2000-2001. December 2000 is the 3rd coolest December after 1989 and 1983.

It shows that La Nina is not the sole reason for winter, though it plays a huge role. Also, there is Arctic Oscillation, North Atlantic Oscillation, Pacific-North America Teleconnection, Pacific Decadal Oscillation, etc.

This is very true if we were talking about a weak or even a moderate ENSO event. However, look at how all STRONG La Ninas have behaved for Texas. EVERY SINGLE ONE was warm and dry. Yes, there were some cold periods, but the overall signal was for big warmth and little rain.

Realizing this, the December 2000 point is a bit irrelevant as that was barely a weak ENSO event. Once an ENSO event moves to strong territory (as we are seeing with this current La Nina) all of those oscillations become increasingly irrelevant. The ONLY reason last winter was so cold during the strong El Nino event was because of the AO moving into record territory that we hadn't seen since the famous winters of the 1970s. This allowed arcitic air (what was available, anyway) to penetrate so far south despite an active southern jet stream that should have shunted things northward... Basically, we'd have to see something like that again to override our strong ENSO signal event this winter, which we won't. The Atlantic won't even be a factor this year, so what we'll be honing in on will be the Pacific.

As we are about to see, any time the Pacific can become favorable for just a little bit, yes, we will see some cold air spilled southward towards Texas. However, don't expect the pattern to lock (like in 2000 or any other weak or moderate ENSO event you can think of). The main signal for this winter will be warmth and lots of it on average. Just look at any winter outlooks by the many knowledgable long term forecasters on the various weather forums out there, and most have the biggest area of warmth around Texas or SE.

Again, this doesn't mean we won't see cold periods (maybe an extreme one ala Feb 89?). But forecasts like "Sunny. Highs in the lower 80s" will be common this winter.

[wxman57]

Highs in the low 80s seem great to me, but I suspect you're being a bit generous with the high temps. La Nina winters are certainly typically warmer and drier for Texas, and I suspect this winter will be so. But with the drier air comes cooler than normal overnight lows. The abundant sunshine will mean warmer afternoon highs, but probably not the 80s. More likely the 70s. Probably won't see too many of those cold, dreary days with lows AND highs in the 30s or 40s this winter.

[TexasMetBlake]

I agree. While we have had times we've touched the 80s in the dead of winter, it is hardly 'common.' I suspect it won't be as dreary this year, but there will be times when it gets cold here. On another note, rarely do you ever see Texas (in the seasonal forecasts) shaded in 'cooler than normal' hatching. It seems that almostevery year they have us shaded in the above normal category. Something else to consider is the Atlantic Oscillation. Eventually, and sooner rather than later, the Atlantic is going to enter a cold phase and the active hurricane seasons that we've grown accustom to will vanish. That really doesn't matter much this year, but it could have implications on the coming winters.

There are a number of factors that determine a warm or cold winter. To think that this winter is going to be shorts and t-shirt weather in January is nothing more than an exaggeration (not that anybody insisted it would be and that's not to rule out that there won't be days in the mid and upper 70s).

[wxman57]

As for the Atlantic Multidecadal Oscillation (AMO), the last several warm phases each lasted around 40-45 years. Cool cycles have tended to last about 25 years. The current warm AMO started in 1995, only 15 years ago, so it could be years from reaching the mid point.

[Mr. T]

I agree. While we have had times we've touched the 80s in the dead of winter, it is hardly 'common.' I suspect it won't be as dreary this year, but there will be times when it gets cold here. On another note, rarely do you ever see Texas (in the seasonal forecasts) shaded in 'cooler than normal' hatching. It seems that almostevery year they have us shaded in the above normal category. Something else to consider is the Atlantic Oscillation. Eventually, and sooner rather than later, the Atlantic is going to enter a cold phase and the active hurricane seasons that we've grown accustom to will vanish. That really doesn't matter much this year, but it could have implications on the coming winters.

The Pacific is MUCH more important to our sensible weather than the Atlantic. If the Pacific is crap, the NAO can be negative and we can still roast.

Anyway, GFS continues the trend of a very El Nino-like stormy pattern developing in about a week. We've got some stormy days ahead.

[srainhoutx]

Well the CPC certainly continues with a 'colder' that normal pattern in the 8-14 day range...

[srainhoutx]

The 12Z GFS continues to advertise an active pattern with 'cold air' poised to drop S in the medium to long range. If the trends continue, we may see our first Blue Norther just prior to Thanksgiving.

[TexasMetBlake]

It's pretty typical for the gfs to advertise something and then keep pushing it off. Eventually, one of those solutions will come to fruition.

[srainhoutx]

OT: Reminder to folks to go to the User Contral Panel, Board Preference and click no to DST (Daylight Savings Time) and submit.

[Mr. T]

The 12Z GFS continues to advertise an active pattern with 'cold air' poised to drop S in the medium to long range. If the trends continue, we may see our first Blue Norther just prior to Thanksgiving.

Yup. The upcoming pattern for the last of November is prime for active weather and big cold fronts. Methinks exciting times are ahead. The global models have been in good agreement since last week about this upcoming pattern change.

GEFS signal is active and cold for much of the country:

http://raleighwx.easternuswx.com/models ... yNA168.gif
http://raleighwx.easternuswx.com/models ... yNA240.gif

[biggerbyte]

Great! The poor Turkey freezes, while Santa sweats.

Lol

Exciting potentials, indeed.

[svrwx0503]

At this time it doesn't look like Friday's event will be anything too terribly significant, but most areas could pick up another very welcome 1/2 inch of rain with some isolated spots possibly receiving 1-2''.

[Ptarmigan]

This is very true if we were talking about a weak or even a moderate ENSO event. However, look at how all STRONG La Ninas have behaved for Texas. EVERY SINGLE ONE was warm and dry. Yes, there were some cold periods, but the overall signal was for big warmth and little rain.

Realizing this, the December 2000 point is a bit irrelevant as that was barely a weak ENSO event. Once an ENSO event moves to strong territory (as we are seeing with this current La Nina) all of those oscillations become increasingly irrelevant. The ONLY reason last winter was so cold during the strong El Nino event was because of the AO moving into record territory that we hadn't seen since the famous winters of the 1970s. This allowed arcitic air (what was available, anyway) to penetrate so far south despite an active southern jet stream that should have shunted things northward... Basically, we'd have to see something like that again to override our strong ENSO signal event this winter, which we won't. The Atlantic won't even be a factor this year, so what we'll be honing in on will be the Pacific.

As we are about to see, any time the Pacific can become favorable for just a little bit, yes, we will see some cold air spilled southward towards Texas. However, don't expect the pattern to lock (like in 2000 or any other weak or moderate ENSO event you can think of). The main signal for this winter will be warmth and lots of it on average. Just look at any winter outlooks by the many knowledgable long term forecasters on the various weather forums out there, and most have the biggest area of warmth around Texas or SE.

Again, this doesn't mean we won't see cold periods (maybe an extreme one ala Feb 89?). But forecasts like "Sunny. Highs in the lower 80s" will be common this winter.

Strong La Ninas from December to February.
1916-1917
1973-1974
1988-1989

Persistant La Nina
1871-1875
1908-1911
1954-1957
1973-1976
1998-2000

Before 1950
ftp://www.coaps.fsu.edu/pub/JMA_SST_Ind ... y.filter-5

1950-Present
http://www.cpc.ncep.noaa.gov/products/a ... ears.shtml

We have hit 90s in the February in 1940, 1986, and 1996. 2 of the 3 occurred in weak La Nina, not strong La Nina. However, with La Nina, we are more likely to hit 90s earlier than average.

Here are rainfall totals for Upper Texas Coast.

Average Rainfall Total During Strong La Nina
Strong La Nina
1916-1917
31.94

1973-1974
60.89

1988-1989
39.29

Average Rainfall Total During Persistant La Nina
Persistant La Nina
1871-1875
Not Available

1908-1911
42.86

1954-1957
36.76

1973-1976
53.98

1998-2000
44.08

Annual Average
47.88

25th
40.505

50th
46.36

75th
54.81

2 of the 3 rainfall average for strong La Ninas are below average, with one above average.

Interesting to note that 1973-74 was wet despite a strong La Nina, one of the strongest on record. Now, let's look at winter (December-February).

Winter Rainfall Total
Strong La Nina
1916-1917
8.12

1973-1974
9.56

1988-1989
9.96

Annual Average
10.69

25th
8.29

50th
10.17

75th
12.66

Winter Temperature
Strong La Nina
1916-1917
57.93

1973-1974
55.73

1988-1989
55.87

Annual Average
55.13

25th
53.62

50th
55.2

75th
56.5

All average is from 1895 to 2010.

Divisional Weather Data
http://www7.ncdc.noaa.gov/CDO/CDODivisionalSelect.jsp

[Mr. T]

The upcoming setup in 7 days would be so awesome in the middle of winter!
http://www.nco.ncep.noaa.gov/pmb/nwprod ... _168.shtml

As it stands, an active wet and cold period will be upon us in 7 days.

[biggerbyte]

K@@L