December Weather Discussion. Will We See Rain?

[kennethb]

Don't we usually get our first snow of the season in Houston and South Louisiana by early December?

[wxman57]

Don't we usually get our first snow of the season in Houston and South Louisiana by early December?

First of all, welcome to the forum, Kenneth. We usually don't get any snow here in Houston. However, early December has been the "hot spot", so to speak, for snow here of late. Having lived in Houston for the past 30 years, I've found that we typically see our first good shot of Canadian/Arctic air the last week of November to the first week of December.

[Baseballdude2915]

By hour 240, the Euro suggests a hard freeze for our area.

11292010 12Z f240.gif

Freezing line takes quite a plunge if that plays out.

It looks like a GFS vs. Euro showdown. Wonder which will begin to sway.

[Baseballdude2915]

Don't we usually get our first snow of the season in Houston and South Louisiana by early December?

In a perfect world yes. We usually have a span of 5-6 years between snow events. The largest snow even in HGX history was Valentines Day. Basically from Thanksgiving-St.Patty's we have a chance, peaking around Christmas. In a La Nina year like this, temperatures will warm in January and February, so If it doesn't happen soon, it might get too late.

[TexasMetBlake]

The 12z euro certainly has my attention as it has been VERY consistent with bringing a deep trough through the area. The run above is very cold showing highs possibly only in the low 30s (sub freezing towards Dallas) with a winter storm of some sort. The GFS is all over the place but seems to have locked on to this idea of a deep trough as well which is certainly encouraging.

[wxman57]

AccuWx PPV Yurpian shows temps in that time period between 5 and 10º, or no winter fun for us.

Where do you see that, Ed? I'm looking at the 12Z EC on the pro site and plotting 2m temps at 240hrs and see 30F over Houston next Wednesday. Or do you mean 5C-10C temps? Euro does have temps here in the upper 30s next Tuesday afternoon.

[tireman4]

THIS IS LAST YEAR, NOT THIS YEAR>>>>

Remember this....could it happen again? Goodness...


From December 1, 2009

Well HGX is getting a bit more bullish on the event...

IT SEEMS THAT YESTERDAY`S 12Z GFS RUN PICKED UP ON A STRONG
SHORTWAVE TROUGH THAT IT HAD NOT PREVIOUSLY RESOLVED. THE
SHORTWAVE IS NOW OVER THE PAC NW THAT WILL MOVE THROUGH THE AREA
ON FRI AS A STRONG JET STREAK PUSHES INTO IT ON THU. TODAY`S 12Z
GFS CONTINUES THIS TREND AS DOES THE 12Z NAM. THIS BRINGS MORE
CONFIDENCE TO FORECAST WINTER PRECIPITATION DURING THE DAY FRI.
THE EVENT MAY BE 4 DAYS OUT BUT WILL DO THE BEST TO HASH OUT
DETAILS OF THE TRANSITION FROM RAIN TO SNOW AS MODEL SOUNDINGS
SUPPORT ALL SNOW BY THE AFTERNOON AS WELL AS ANY HEAVIER PRECIP
BANDS. THE NEW HAZARDOUS WEATHER OUTLOOK WILL DETAIL OUR LATEST
THINKING BUT WILL BE UPDATED AGAIN THIS AFTERNOON. AFTERNOON
FORECAST PACKAGE WILL ALSO FEATURE AN SPS TO OUTLINE WINTER
PRECIP THREATS/HAZARDS AND TIMING OF THE EVENT FOR AREAS OF SE TX.

[srainhoutx]

Expect the NWS to lean more on the GFS solution than the Euro at this point in their afternoon discussions.

[TexasMetBlake]

DFW AFD: (I don't agree with the finding about the euro)

THE EXTENDED FORECAST IS DIFFICULT DUE TO THE EXTREME UNCERTAINTY
PROVIDED BY THE GUIDANCE. THE ECMWF HAS HAD LITTLE TO NO RUN-TO-
RUN CONTINUITY...AND THE GFS ENSEMBLE MEMBERS SHOW AN EXTREMELY
WIDE RANGE OF SOLUTIONS FOR EARLY NEXT WEEK. GUIDANCE RANGES FROM
THE ECMWF DEVELOPING A LARGE CUTOFF SYSTEM ON MONDAY OVER THE
DESERT SOUTHWEST THAT DROPS INTO MEXICO...WITH A CHANCE OF WINTER
WEATHER OVER NORTH TEXAS ON TUESDAY...TO SOME OF THE GFS MEMBERS
FORECASTING RIDGING OVER THE SAME AREA. THE OPERATIONAL GFS
APPEARS TO BE ONE OF THE MIDDLE MODEL MEMBERS AND FORECASTS
COOLER TEMPERATURES BY TUESDAY AS COLD AIR DROPS SOUTH FROM THE
PLAINS. WE WILL STICK WITH THIS SOLUTION AS A PLAUSIBLE OUTCOME
AND WHEN GUIDANCE IMPROVES WE WILL ADJUST ACCORDINGLY.

In my opinion only, I think the Euro has been one of the more consistent runs showing a deep trough. I'm not exactly sure why DFW said there was little to no run-to-run continuity. The gfs is the one that jumps from one extreme to the other. Now if they are referring to the axis placement, then that's one thing. But nonetheless, since the Euro is such an extreme solution, expect full well the NWS to stick with the gfs like Steve said until the time gets closer. Eventually, the models (gfs and euro and cmc) will align but the question is when.

[wxman57]

There have been tremendous differences between the 00Z and 12Z Euro runs in the past 2-3 days.

[harpman]

Ok, gentlemen, which is it? Has the euro been consistent or not? One of you says yes, the other says no. Flip a coin?

[TexasMetBlake]

Well the last 5 or 6 runs I've seen have all shown a deep trough. Now if you go beyond that, then I don't know.

[harpman]

Thank you sir! I'm in New Orleans and am interested in the wx your way because many times what Houston gets, we get a day or so later.

[helloitsb]

I was looking at the 6z gfs run this morning on Twister Data and it shows snow (little bit) being around for a good 24 hours (although I know the knew run has come out already and does not snow any depth for this time)



Starts at hour 204

[srainhoutx]

Without getting into the finer details of the models, the GFS (15 days) sniffed the pattern out in the long range and the Euro (10 day guidance) has been more in line with a trough and Upper Air feature. That said, it's still a long way out and next Monday is a lifetime in model world. And as the NWS offices are saying, it’s worth noting and watching.

[wxman57]

Well the last 5 or 6 runs I've seen have all shown a deep trough. Now if you go beyond that, then I don't know.

Yes, all EC runs did show a deeper trof than the GFS, but there was considerable variance on the timing of the cold air arrival with respect to the passage of the trof axis. 00Z runs tended to move the front through right ahead of the trof axis, with no post-frontal precip. 12Z runs held the trof axis back well west of the cold air, resulting in winter weather fairly far to the south. That's a difference between sunny and cool weather and cloudy with frozen precip down south.

[harpman]

Ok, it's more clear now. Thank you, sir.

[TexasMetBlake]

Well the last 5 or 6 runs I've seen have all shown a deep trough. Now if you go beyond that, then I don't know.

Yes, all EC runs did show a deeper trof than the GFS, but there was considerable variance on the timing of the cold air arrival with respect to the passage of the trof axis. 00Z runs tended to move the front through right ahead of the trof axis, with no post-frontal precip. 12Z runs held the trof axis back well west of the cold air, resulting in winter weather fairly far to the south. That's a difference between sunny and cool weather and cloudy with frozen precip down south.

I understand. In the words of my professor: "Acknowledged." LOL

[Mr. T]

AccuWx PPV Yurpian shows temps in that time period between 5 and 10º, or no winter fun for us.

You seriously suck with model analysis. Just spittin' out stuff with no interpretation

Of course, your favorite thing is to read everything verbatim, but the main point to get out of that model run is that the pattern is prime for a possible snow event across Texas and even across parts of S TX.

How is that freeze holding off until December working out for you?

[Mr. T]

Judging by the latest ZFP from HGX, it looks like they are completely disregarding the GFS and going with the Euro. They have highs in the 50s early next week instead of the 70s as the 12z GFS shows.