Interesting New Orleans Wx Discussion

[Janie2006]

Hmmmm, what's this?

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
415 AM CST SUN DEC 17 2006

.DISCUSSION...
WE ARE ON THE CUSP OF CHANGABLE WEATHER IN THE UPCOMING
WEEK...SOME WHICH CAN BE QUITE DRAMATIC GOING INTO CHRISTMAS DAY.

NEXT WEEKEND...LOOKING FOR THE PACIFIC FRONTAL BOUNDARY TO BECOME
STATIONARY IN THE CENTRAL GULF OF MEXICO AND BECOME OVERRIDDEN BY
HEALTHY SOUTHERN BRANCH FLOW TO ONSET OVERRUNNING HEAVY RAINFALL
PATTERN FOR NEXT SUNDAY AS GULF LOW CYCLOGENESIS LIKELY TAKES
PLACE IN THE WEST GULF ON THE FRONTOLYTIC BOUNDARY. IF THIS
SCENARIO EVOLVES AND STARTS INDUCING ARCTIC AIR SOUTHWARD INTO THE
GULF STATES...THEN A TRANSITION TO WINTER TYPE PRECIPITATION CAN
BECOME THE END RESULT FOR CHRISTMAS EVE AND CHRISTMAS DAY IN
PORTIONS OF THE GULF STATES. THERE REMAINS QUITE A BIT OF
UNCERTAINTY THIS FAR OUT TO DETERMINE HOW DEEP THE COLD LAYER WILL
BE AND WHICH TRACK ANY DEVELOPING LOW WOULD TAKE TO SAY WITH
CONFIDENCE WHAT TYPE OF PRECIPITATION WILL ACTUALLY OCCUR AND
WHERE. SUFFICE IT TO SAY...THE CONDITIONS APPEAR TO BE SETTING UP
FOR A VERY ACTIVE WEATHER PATTERN FOR NEXT WEEKEND LEADING INTO
CHRISTMAS DAY. TO RULE OUT ANY KIND OF WINTER PRECIPITATION IN THE
DEEP SOUTH IN THE EXTENDED PERIODS AND BEYOND WOULD NOT BE
PRUDENT AT THIS TIME. LOCAL LONG RANGE HOVMOLLER PROGNOSTIC
SCHEME INDICATED A FAVORABLE PERIOD OF WINTER STORM ACTIVITY
DURING THAT TIME FRAME...DATING BACK TO DECEMBER 9TH OUTLOOK AND
THE LATEST MODEL TRENDS ARE OFFERING CONFIDENCE IN THIS SCENARIO
POSSIBLY OCCURRING TO SOME EXTENT. THE SCHEME INDICATED A 3-5 WAVE
TRANSITION WITH A FULL LATITUDE TROUGH INDICATED IN THE MIDDLE OF
THE NATION TAPPING AN ARCTIC AIRMASS THAT IS CURRENTLY SITUATED IN
SIBERIA. GIVEN THE INTEGRITY AND PERSISTENT STRENGTH OF THE
SOUTHERN BRANCH AND ITS INTERACTION AT THE BASE OF A LONG WAVE
TROUGH CAN MAKE THE GULF STATES AN ACTIVE WEATHER AREA NEXT WEEKEND.
STAY TUNED.

You might say we need a "bear watch". LOL!

Now, this is a peek into the extended forecast period and we all know that situations often change. KMOB (NWS-Mobile) is nibbling on this a bit, but states that the 500 MB temps will be far too warm.

Personally, I think they just like to tease us a bit just before Christmas. In any case, it will be interesting to see what happens and where.

Edited to add: I left out the part of the discussion dealing with the short-range forecast and jumped ahead to the good stuff.

[wxman22]

The Houston NWS also mentions the possibility:

LOOKING EVEN FURTHER INTO THE EXTENDED AND ASSUMING ECMWF/GFS BOTH
END UP BEING RIGHT...XMAS EVE AND XMAS DAY COULD GET KINDA
INTERESTING. STRONG COLD FRONT MOVES INTO THE AREA WHILE A DEEP MID
LEVEL TROF EXTENDING ALL THE WAY INTO CNTRL MEXICO PROVIDES
OVERRUNNING MOISTURE... 47

[JonathanBelles]

(music) im dreaming of a white christmas!

[Ptarmigan]

The Houston NWS also mentions the possibility:

LOOKING EVEN FURTHER INTO THE EXTENDED AND ASSUMING ECMWF/GFS BOTH
END UP BEING RIGHT...XMAS EVE AND XMAS DAY COULD GET KINDA
INTERESTING. STRONG COLD FRONT MOVES INTO THE AREA WHILE A DEEP MID
LEVEL TROF EXTENDING ALL THE WAY INTO CNTRL MEXICO PROVIDES
OVERRUNNING MOISTURE... 47

I hope this is true.

[Opal storm]

Wow,well I will be keeping an eye on this.I don't care about snow just as long as it's cold on Christmas I'll be happy,right now it's 73 degrees outside and feels even warmer in the sun.....ugh.

[Opal storm]

New Orleans 2:53pm AFD

.DISCUSSION...

A COLD FRONT WILL NOSE ITS WAY SOUTH INTO THE AREA LATE TUESDAY
AND TUESDAY NIGHT AS AN UPPER TROUGH DIGS OFF THE EAST COAST.
THIS FRONTAL BOUNDARY WILL MOVE BACK NORTH WEDNESDAY AND WEDNESDAY
NIGHT IN ADVANCE OF AN UPPER LOW/TROUGH FORECAST TO MOVE NORTHEAST
OUT OF THE SOUTHWEST U.S. AND ACROSS THE CENTRAL CONUS THROUGH THE
MIDDLE AND END OF THE WEEK. THE COLD FRONT ASSOCIATED WITH THIS
SYSTEM WILL ONLY SLOWLY MOVE ACROSS THE FORECAST AREA THURSDAY INTO
FRIDAY. IT APPEARS THAT MUCH OF THE AREA SHOULD SEE A DECENT
AMOUNT OF RAINFALL WITH THIS SYSTEM BEFORE THE PRECIPITATION TAPERS
OFF FRIDAY NIGHT AND EARLY SATURDAY. THE GFS FORECASTS MORE ENERGY
TO DIVE SOUTH ACROSS THE WESTERN U.S. LATE IN THE WORK WEEK WITH A
CLOSED MID/UPPER LEVEL LOW FORMING OVER NORTHERN MEXICO BEFORE
EJECTING EAST ACROSS TEXAS AND THEN INTO LOWER MISSISSIPPI VALLEY
AND GULF COAST STATES EARLY NEXT WEEK. AS THIS HAPPENS...CYCLOGENISIS
IS ADVERTISED TO TAKE PLACE OVER THE NORTHWEST GULF WITH THE
SURFACE LOW MOVING EAST NEAR THE LOUISIANA COAST SUNDAY NIGHT AND
CHRISTMAS DAY. ALTHOUGH IT IS STILL EARLY AND TIMING COULD BE AN
ISSUE...THE GFS FORECASTS ABUNDANT MOISTURE WITH THIS SYSTEM AND
LOCALLY HEAVY RAIN COULD BE A THREAT FROM LATE SUNDAY INTO
CHRISTMAS. THICKNESSES ARE FORECAST TO DROP SHARPLY CHRISTMAS
NIGHT...MONDAY NIGHT...WITH THE POSSIBILITY OF SOME FROZEN
PRECIPITATION AFFECTING PARTS OF THE GULF COAST STATES BEFORE THE
SYSTEM MOVES OFF TO THE EAST TUESDAY AND WEDNESDAY.

[MGC]

Highly doubtfull the Gulf Coast gets a White Christmas 2 out of 3 years. 2004 was the first time in recorded history that it snowed in New Orleans on Christmas day. But, its nice to dream......MGC

[PTPatrick]

for what its worth , current forecast isnt for a white christmas, but perhaps more of a cold rainy christmas eve/day and a cold and slushy day after christmas, at least for MS gulf coast and NOLA area...possibly white xmas is portions of east texas and MAYBE NW LA. Snow still in the model for N MS and N LA on Tuesday after. the 18z paints a little less moisture near the coast when it is coldest tuesday evening/wed am time frame...looks like wraparound in NMS for that matter, which is ALMOST always over done on GFS this far out. In any case, another chase of flakes appears to show up later christmas week, which looks a little more like a typical set up for NGC snow. So having said that...I would gladly take a white christmas week, or a white new year in south ms.

I am acutally just glad that it is not going to be 60s and 70s(at least according to GFS) in pascagoula for christmas. I fly out from denver on saturday missing my only chance for a white christmas to be with my folks on the coast. It is cold here and we have had plenty of snow, so perhaps I will just pack some snow and cold and bring it with me

[Janie2006]

Winter wx on Christmas (or somewhere near the 25th) would be the frosting on the cake for me this fall/early winter season. At least let it be cold....I'd be as pleased as punch.

[beachbum_al]

Snow on Christmas Again....Yes bring it on.

[Opal storm]

GFS showing a washout along the central Gulf coast on Christmas day.
http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_192l.gif

We do need the rain so I really don't mind.

[CajunMama]

Highly doubtfull the Gulf Coast gets a White Christmas 2 out of 3 years. 2004 was the first time in recorded history that it snowed in New Orleans on Christmas day. But, its nice to dream......MGC

You never know what is possible. It snowed here in Lafayette on New Years 2 years in a row. I'd a never thunk that!!!

[MiamiensisWx]

Based on the current synoptics evidenced on time-lapsed water vapor imagery, I would not be surprised if the advertised solutions depicted by the GFS and related models may mildly verify. Temperatures, thickness, and timing - as well as the intensity and placement of the synoptics and the potential low formation - may be among the key factors here determining the extent of potential light frozen/mixed precipitation in the northern Gulf coast region. As it is still roughly 124 hours (at least) out, I would be on the cautious side as of now.

[Janie2006]

Yup, yup. I think "caution" is the word of the moment. The latest GFS runs (posted on another thread so I don't see any particular need to re-post them here) are very interesting, but I'm not biting on the bait yet. On the other hand, I recall that the models were consistent in bringing winter wx to the deep South several days before the Superstorm of March 1993. Some people dismissed those model runs and (unfortunately for them) those folks ended up with a lot of busted forecasts. We don't have the same situation here, but it is something we can learn a lot from. Therefore, I am certainly not dismissing the possibility of winter wx out of hand. Rather, I'm taking a wait and see approach. I'd like to have a few more model runs behind us.

We will have to have cyclogenesis out in the Gulf to bring precip over any cold air that happens to be in place. The 2004 event featured just such a scenario along the Northern Gulf Coast. So, I'm in agreement with Miami...I think many things depend on the development and track of the potential Gulf low pressure system.

[Dean4Storms]

I don't see much of a chance for anything near the coast, not much cold air there. But it does look interesting come New Years.

[LaBreeze]

As long as we don't have to have the air conditioners humming at that time of year. Would be nice to have some cold air and some sort of mixed precip in the bag. We'll cross our fingers and toes and wait and see.

[Brent]

I like the 06z run... this is at 6am on Christmas.

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_174s.gif

(We got no snow from the 2004 storm).

Noon:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_180s.gif

Midnight:

http://www.nco.ncep.noaa.gov/pmb/nwprod ... p_192s.gif

[cajungal]

Anything is possible, but not getting my hopes up. It did snow almost back to back here in my town, so anything is possible. It snowed Feb 1988 which was my first snow experience in Louisiana. I was 11 years old. I was sleeping and my parents woke me up to go look. I ran outside in the middle of the night in my pajamas to see the snow. About an inch covered the ground. And it snowed again on December 23, 1989. This time about 2 inches covered the ground.

[Brent]

and of course... the 12z is warmer with less precip. Blah. Story of my life.

[Kennethb]

The good GFS giveth and the bad GFS taketh away.