December Weather Discussion. Will We See Rain?

[biggerbyte]

Well Sunday is here folks, and I am sure some are disappointed with the forecast for our area.
With the pattern that we are in this winter season, the best we can hope for is cold, but not real cold. The bitter cold gets pushed east. The kind of winter we would see this year would support falling frozen precip. of some sort, depending on the conditions, and could stick on some surfaces if that surface can sustain a temp at or below freezing.

So, here is what we have...

Tuesday is the day to watch this week for some possible moisture mixing in with the cold air.
We'll see if we can get anything magical with that. No white-outs, folks.. Sorry!
As you will see, the long range models were bogus talking about big cold for us with this fropa. They are up to no good with the next push of cold air as well.

My opinion is, we have to remember where we live. While this winter may be nothing to write home about, we should be used to it by now. We've been fortunate to have had some extraordinary events over the past few years, some back to back. Maybe we can squeeze out a sleet pellet or snow flake or two even this season.

We'll watch for pattern changes that could turn all of this on its ear. Right now, I don't see it. One thing is for sure. The models are all wet. No pun intended.


BB

[Ptarmigan]

I hope December 20-21 will be nice because there is a total lunar eclipse that night. The next one won't be until April 15, 2014.

[srainhoutx]

HPC regarding the next surge of 'cold air'...we're not the only folks that have seen the models take away a storm...

12Z GUIDANCE RUNS OF GFS/CMC/UKMET OFFER THREE ENTIRELY DIFFERENT
SOLUTIONS AND REINFORCE THE UNCERTAINTY OF PREVIOUS RUNS. UKMET
HAS VERY SIGNIFICANT MID LEVEL STREAM SEPERATION AT DAY 6 SAT MORE
SO THAN ANY OTHER MODEL OR PRIOR RUN IN THE SRN PLAINS WITH AN
UPSTREAM STRONG DIGGING UPPER LEVEL JET THAT WOULD IMPLY A MORE
N-NEWD MOVEMENT TAKING THE LOW WEST OF THE APPLACHNS AFTER DAY 7
SUN. CMC HAS ALSO GONE MUCH CLOSER TO THE 00Z ECMWF SOLUTION OF A
STRONG CENTRAL CONUS STORM LATE PERIOD AND EARLY NEXT WEEK AS HAS
12Z NAVY NOGAPS. MOST CONSISTENT IS THE GFS WHICH HAS A WEAKER
FLATTER DIGGING SHORTWAVE THAN ITS PRIOR RUN BUT REMAINS
REASONABLY CLOSE TO ITS 00Z AND 06Z SOLUTION AND ECMWF WHICH
CONTINUES ITS SOLUTION FROM 00Z.

A MINOR SFC PROG MADE ADJUSTMENT CLOSER TO THE 00Z ECMWF ENS MEAN
AND LASTEST 12Z GFS WITH A REFORMING COASTAL LOW OFF VA CAPES LATE
SUNDAY. THIS CONTINUES THE LOW CONFIDENCE AND UNCERTAINTY WITH THE
SHORTWAVE AMPLITUDE AND INTENSITY ALONG WITH THE SFC LOW TRACK
DAYS 7-8 SUN/MON. CONSENSUS OF MODEL RUNS AT 12Z IS WEST OF THE
APPLACHNS AND A WESTWARD ADJUSTMENT MAY BE NEEDED TOMORROW.

[Ptarmigan]

I think the closest analog for this winter are:
Values are based on December to February average of NAO, AO, and PNA indices and are multiplied by 10.
1916-1917
NAO=-24 Extremely Strong Negative
AO=N/A
PNA=N/A

1949-1950
NAO=+6.333 Weak Positive
AO=+2.835 Neutral
PNA=-16.9 Strong Negative

1955-1956
NAO=-12.667 Moderate Negative
AO=-12.257 Moderate Negative
PNA=-14.767 Moderate Negative

1973-1974
NAO=+11 Moderate Positive
AO=-1.46 Neutral
PNA=-3.533 Neutral

1975-1976
NAO=+4.333 Neutral
AO=+9.933 Weak Positive
PNA=-3.7 Neutral

1988-1989
NAO=+20.333 Extremely Strong Positive
AO=+26.88 Extremely Strong Positive
PNA=-3.833 Neutral

1998-1999
NAO=+17.333 Strong Positive
AO=+6.483 Weak Positive
PNA=-0.167 Neutral

1999-2000
NAO=+16.333 Strong Positive
AO=+11.297 Moderate Positive
PNA=+1.7 Neutral

I think the closest analog is either 1973-1974, 1988-1989, and 1998-1999 because the La Nina came off of an El Nino. Here are current conditions. If you are talking about NAO, AO, and PNA, based on the current trends, I think the closest analog would be 1955-1956. However, there was a strong La Nina that was also persistent in the 1950s, which caused a serious drought in Texas, unlike 1988-1989, which had a persistent El Nino from 1986-1988.

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

ENSO=-15 (Based on all El Nino region temperature and averaged out)Trending towards negative
NAO=-13.4 Trending towards negative
AO=-12.7 Trending towards negative
PNA=-11,9 Trending towards negative

NAO, AO, and PNA daily value
http://www.cpc.ncep.noaa.gov/products/p ... ndex.ascii

[srainhoutx]

FYI: A Nationwide Data Outage has occurred with the NWS Sites. They are working on a fix. Edit to add...

NCF Alert Administrative Message
Sun Dec 5 22:31:25 2010 GMT
NOUS71 KNCF 052230
ADANCF
.
THE AWIPS SBN SIGNAL HAS BEEN RESTORED.
ALL NEW DATA IS PASSING WITHOUT ANY
PROBLEMS. WE HAVE RETRANSMITTED A SMALL
AMOUNT OF DATA, BUT MOST OF THE PREVOUS
DATA WAS LOST.
.
THANK YOU FOR YOUR CONTINUED PATIENCE.



Our disturbance as the data comes back online...

[srainhoutx]

I expect some frost across the Northern Areas by morning. Skies have cleared and winds have decoupled with DP's in the upper 20 and low 30's across those areas.

[Ptarmigan]

That Pacific storm is quite impressive.

[Andrew]

Been a long weekend but I see that not much has changed. Looking at the GFS it does not hint at any "winter fun" anytime soon. Looks like the Euro is what we are going to have to look to for any "fun" possibilities.

[wxman57]

No Euro "fun" this week or next, either. Just a couple of cold fronts, one with cold rain, the other probably dry.

[ticka1]

Just glad we are getting consistant shots of cold weather! At least we get to see the temps drop into the 30's and from what I am seeing today might not get out of the 50's! This is my kind of weather!

[srainhoutx]

The 12Z GFS Monday version suggests perhaps some flakes for our neighbors in Louisiana. That model also suggests a Coastal trough/low will form along the TX Coast and has come in a bit 'wetter' for our area. Even some light rain would be nice in this very dry pattern that appears to have no end in sight.

[wxman57]

The projected (GFS) vertical sounding for SW Louisiana (north of Lake Charles) is considerably different than the one for Houston. I notice that the SW LA sounding has all the clouds and precip in a sub-freezing airmass, though surface temps are in the upper 30s. For our area, all clouds (and precip) are forecast to be located in an ABOVE-freezing airmass. Basically, the cold air is deeper to our northeast and east tomorrow night. Just some patches of light rain here.

[srainhoutx]

For wxman57. Allan had to update his charts to accommodate just how much the NAO is suggested to tank via the Euro...

[sambucol]

For wxman57. Allan had to update his charts to accommodate just how much the NAO is suggested to tank via the Euro...

What does the NAO tanking mean for us?

[srainhoutx]

Probably that would suggest we will not see any major long lasting warming trend anytime soon. It also opens the door to some cold intrusions as we near Christmas. Perhaps and still a long way out, but some mighty cold air that has been building across Eurasia could just spill across into North America. We will see, but I'm not ready to cancel winter just yet. Also, the 18Z NAM has come in a good bit wetter with the U/A disturbance for tomorrow night. Temps are a touch colder as well with that model run. Early next week looks down right brutal E of the Mississippi. Possible blizzard conditions to our N and E as well as a potential citrus damaging freeze into Florida.

[TexasMetBlake]

I hope it's not a winter when all the cold air goes east and we just get a 'glancing blow.'

Also, if last weeks Euro runs would have panned out, we'd likely be under a Winter Storm Watch right now.

[srainhoutx]

For what it's worth, the 18Z WRF has come in a bit stronger with the disturbance for tomorrow night as well. Here's to hoping for some rain, albeit light!

[Mr. T]

All that NAO is going to do is keep us cool, but nothing out of the ordinary. The Pacific will allow everything to go east, and when the NAO begins to rise, we torch...

Again, the Pacific is way more important for us than the Atlantic.

[Mr. T]

As long as that large GOA trough remains in place throughout the winter (which it likely will considering the strength of this negative ENSO), any cold air that forms will likely go east, even with a large -NAO block as we are seeing now... Actually, it is this -PNA, large -NAO that will send some very cold (record?) air to the SE and Florida, while we recieve a glancing blow.

IF anything in the Pacific fluctuates, such as the GOA low moving out of the Aleutians into a more favorable setup for ridging across the western coasts of the US and Canada, we could see, as wxmx noted on AmWx, a pretty good push of cold air into our area (that's not just 50s / 30s)

Also, that rather stationary feature is also helping to keep a dry NW flow aloft over our area thanks to the absense of ridging to our east (thanks -NAO), which will keep any passing disturbances that could give us some welcome rainfall to our north.

[biggerbyte]

Ditto on what T said. Looks to be a simple winter for us. Hard to believe that folks in Florida can get more winter weather than this area.