December Weather Discussion. Will We See Rain?

[helloitsb]

...THE FACT THE 12Z DETERMINISTIC MODELS DID
NOT MATCH WELL WITH THE ENS MEANS WILL ALLOW THE ORIGINAL
PREFERENCE TO BE KEPT AS IS.

Do you mind explaining or paraphrasing this last part (really just "THE ORIGINAL PREFERENCE TO BE KEPT AS IS.")

[srainhoutx]

...THE FACT THE 12Z DETERMINISTIC MODELS DID
NOT MATCH WELL WITH THE ENS MEANS WILL ALLOW THE ORIGINAL
PREFERENCE TO BE KEPT AS IS.

Do you mind explaining or paraphrasing this last part (really just "THE ORIGINAL PREFERENCE TO BE KEPT AS IS.")

What the HPC is doing is keeping the thought/forecast of the Morning Updated Prelim Discussion until there is a better consensus regarding the models.

[biggerbyte]

Normal long range model poo. Fun to watch and dream. Saturday or Sunday will be telling.

[Baseballdude2915]

If "ifs" and "buts" were candy and nuts, we would all have a Merry Christmas.

[srainhoutx]

While we have had visions of snow storms dancing in our heads, the temps are dropping this evening. It looks like another freeze event is ahead tonight for the usual 'favored' cold spots. What a way to end November and begin December. I suspect that many will continue to monitor the model madness...

[tireman4]

Woo Hoo...Aint winter fun.... I mean late fall....

[biggerbyte]

Where is everyone all of the sudden?

[srainhoutx]

The 00Z NAM at 84 hours...yeah, I know...suggests the front is entering the Panhandle. The Upper Low is tapping some sub tropical moisture into CA...good night!

[Baseballdude2915]

Any body out there?

[TexasMetBlake]

I'm very surprised nobody has seen the 00z GFS...something to get excited about. It took a giant leep forward towards the last nights 00z Euro. While still showing only a cold rain here, this run is colder than the previous and is more aggressive with the qpf over our area. We shall see...

[TexasMetBlake]

00z Euro: colder but a dry northwest flow. The southern stream trough is gone. Major freeze but no snow this run....go figure.

[C2G]

Any body out there?

That's what happens when an event becomes a non-event in less than 24 hrs.

[srainhoutx]

Good morning. Talk about models flip flopping, lol. I just took a look at the GFS, Euro and Canadian and what a complete swap from previous runs. The intriguing issue is the faster arrival of the cold front (Saturday night/Sunday morning) and then the stronger push of even colder air to follow on Monday night/Tuesday morning. What does look likely is a strong punch of cold air is heading S into TX and may well be the coldest we've seen so far. Also, any shortwave activity and attending moisture is the 'key' to getting any wintry weather in TX. All in all we really don't know any more this morning than we have the past several days and the TX NWS offices are stating that regarding the moisture. What they are talking about is the colder air and faster arrival of that air. Stay tuned as they say. We are a long way from actually knowing how this situation is going to eventually play out.

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
314 AM EST WED DEC 01 2010

VALID 12Z SUN DEC 05 2010 - 12Z WED DEC 08 2010

A DEEP CYCLONE IS EXPECTED TO CONTINUE HAUNTING THE NORTHEAST AND
ATLANTIC CANADA THROUGH THE PERIOD...SLOWLY DEEPENING WITH
TIME...WHICH WILL REINFORCE THE COLD AIR ACROSS MUCH OF THE
EASTERN AND CENTRAL PORTION OF THE LOWER 48. OFFSHORE THE PACIFIC
NORTHWEST AND WESTERN CANADA...A LARGE DEEP CYCLONE AND VARIOUS
RELATED SHORTWAVES ROTATING AROUND IT WILL BRING PACIFIC FRONTS
INTO THE PACIFIC NORTHWEST EARLY TO MID NEXT WEEK. THE GUIDANCE
IS IN GOOD AGREEMENT ON THESE IDEAS.

THERE REMAIN TWO SYSTEMS WITH WHICH THE MODELS SHOW CONSIDERABLE
DISAGREEMENT AND LARGE DAY-TO-DAY AND RUN-TO-RUN CONTINUITY
CHANGES. THE FIRST IS A SHORTWAVE MOVING FROM THE MIDWEST THROUGH
THE MID-ATLANTIC STATES THIS WEEKEND. THE ECMWF IS BACK ON BOARD
WITH ITS CLOSED MID-LEVEL CYCLONE MOVING THROUGH VIRGINIA...THOUGH
IT IS WEAKER THAN SEEN ON OCCASIONAL RUNS FROM THE PAST FEW DAYS.
HOWEVER...THE SHORTWAVE LEADING TO THIS FEATURE SHOULD BE SHEARING
OUT THROUGH THE REGION...NOT CLOSING OFF. A 00Z GFS/00Z CANADIAN
SOLUTION SHOULD WORK OUT BEST HERE. LIGHT SNOW IS POSSIBLE WITH
THIS SYSTEM...THOUGH ITS LOCATION REMAINS UNCERTAIN.

THE BIGGER DISAGREEMENT REMAINS FROM THE SUBTROPICAL EASTERN
PACIFIC INTO THE SOUTHWEST AND SOUTHERN PLAINS WHERE THE
GFS...ECMWF...AND CANADIAN HAVE COMPLETELY SWAPPED POSITIONS
WITHIN THE DETERMINISTIC SPREAD SINCE THIS TIME YESTERDAY.
TODAY...THE ENSEMBLE MEMBERS ARE MOST IN LINE WITH THE 00Z GFS
/ONLY 3 OF THE 90 SUPPORT THE SLOWER ECMWF AND CANADIAN
SOLUTIONS/. INDEED...A SLOWLY PROGRESSIVE RIDGE ACROSS SOUTHWEST
CANADA FAVORS A RELATIVELY PROGRESSIVE DEEP CYCLONE 20 DEGREES
UNDER ITS BASE ACROSS THE DESERT SOUTHWEST...SO TELECONNECTIONS
ARE ABOARD THE QUICKER SOLUTION AS WELL. OVERALL...USED A
COMPROMISE/BLEND OF THE 00Z GEFS MEAN/00Z GFS WITH SOME
ADJUSTMENTS ACROSS ATLANTIC CANADA/THE NORTHEAST AS WELL AS THE
GULF COAST MADE PER 12Z GLOBAL ENSEMBLE ENSEMBLE GUIDANCE LOW
CLUSTERING. THIS SOLUTION MAINTAINED REASONABLE CONTINUITY.

[srainhoutx]

Updated HPC Prelim Discussion...a big change to the slower Euro Ensemble solution...Hmmm...

UPDATED PRELIM PROGS STARTED OF WITH EARLY PRELIM CONTINUITY DAY
3-4 THEN TAPERED TO A MIX OF 30% CONTINUITY AND 70% ECMWF ENSEMBLE
MEAN BY DAY 7. THE ECMWF MEAN WAS CHOSEN BECAUSE OF OUR PREFERENCE
FOR ITS SLOWER SCENARIO IN BRINGING THE CLOSED LOW INTO THE SWRN
CONUS DAYS 5-6. THIS IS A CHANGE IN THINKING FROM THE EARLY PRELIM
WHICH FAVORED THE FASTER GFS MOVEMENT OF A CLOSED LOW OFF CA
COMING INTO THE SWRN PORTION OF THE GFS. WE PREFER THE SLOWER
ECMWF/ECMWF MEAN MOVEMENT OF THIS SYS INTO THE SWRN STATES
CONSIDERING THE GFS PROGRESSIVE BIAS ON DEEP FULL LATITUDE
TROFS...AND THE THE DEEP UPSTREAM KICKER TROF ALONG 150W IN THE
GULF OF ALASKA THE FIRST PART OF NEXT WEEK. IN HINDSIGHT...I THINK
THAT I SHOULD HAVE DOWNPLAYED THE FASTER GFS SOLUTION IN THE SW
MORE ON DAYS 4-5 THAN SHOWN IN THE 500MB GRAPHIC.

[srainhoutx]

WE NEED COLD WE NEED SNOW WE NEED IT NOW. I REFUSE To tolerate negativity.
yesterday,because of one model run,THIS FORUM literally died and everyone was let down. I REFUSE TO ACCEPT THAT.
DONT BELIEVE THE MODELS. be positive with thoughts an analysis. Dan is doing everything he can to bring us the cold and frozen stuff we want. he needs our energy to assist him.
hey srain,can i start a thread about channeling Dan,and assisting him with the energy he needs to help us?

You are doing very well getting that point across right here in this thread, AZ.

[srainhoutx]

Alright, the 12Z GFS is running and so far through hour 78, it suggests the front is entering the TX Panhandle and the Upper Air feature is W of N CA.

[srainhoutx]

By hour 102, the front is off the TX Coast and the colder air is lagging back across KS waiting on the West Coast trough. Cold air is beginning to spill S from Canada as well. Also of note is there appears to be some sub tropical connection being tapped as the trough begins to head inland along the CA Coast.

[srainhoutx]

At hour 138, the U/A disturbance is further N across CO, but swings SE over Western OK/NE TX. Some new wrinkles are a piece of Upper Air energy SW of CA and moisture returns across Southern TX in response to the shortwave energy to our N.

[srainhoutx]

Through hour 168 there is some moisture (hour 140), but it is quickly shunted S. The GFS does not appear as cold, but at this range, it is not that important. What does look different is the coldest air appears to be heading of to our E. The bolcking pattern across the Atlantic rather stout and a robust vortex sets up just N of the Great Lakes.

[wxman57]

According to the 12Z GFS, the cold air reaches us late Saturday night (midnight-ish). Nothing too cold at first. Weak short wave passes by to the north on the morning of the 7th. May produce a bit of precip here (rain), but temps at the surface and aloft are well above freezing, probably in the low to mid 40s. Cold air spills south across Houston after the passage of the short wave on Tuesday, but precip is long gone by then. Not much change from earlier runs, and similar to the last Euro and Canadian. I don't see anything to indicate any snow "threat" down here. Sorry, AZ.

GFS has some light snow in southern Kansas on Tuesday: