New Year's Eve Weather

[srainhoutx]

Indeed you have, sir ... indeed you have.

Now if we can just get that darn PNA to get close to neutral. See what you can do about that, srain!

I'm trying buddy, I'm trying...

12152010 12Z GFS_3_2010121512_F348_SNOWIN_SURFACE.png

12152010 12Z GFS_3_2010121512_F360_SNOWIN_SURFACE.png

[Ptarmigan]

I notice the map Srain that there is snow in North Texas. Don't know if it means anything. Would be nice to see snow.

[Kludge]

Truckers coming south down I45 will be laden with snow, which will quickly melt once south of I20. This may be our primary source of moisture in the coming weeks.

We'll take it.

[wxman57]

That was most likely just a lone, fantasy long-range GFS event. I wouldn't put much stock in that run, as the feature it had causing the snow was a very small/weak disturbance 2 weeks out. The GFS can hardly predict such features 3-4 days out much less 2 weeks out. Later runs have the sub-freezing air way up north in the Central Plains at that time.

[srainhoutx]

Major differences between the Euro and the GFS regarding the cold front and a deep West Coast trough next week just prior to Christmas...

[wxman57]

Yes, there are major difference between the models just out to the next week. That's why I'd pay little attention to individual GFS runs as far as the weather 2 weeks out. Current GFS has us mostly dry through January 1st Just a few periods of light rain.

[srainhoutx]

And those differences continue. I suspect that we are going to see some crazy shifts via all medium/long range guidance in the days ahead as the numerical models struggle with the pattern change and how the Pacific will respond. We are in somewhat 'uncharted' territory in regard to the strength of the -AO and the affect of that relaxing feature and a shift in NAO and PNA regime.

[TexasMetBlake]

What has happened to all our weather? I haven't seen lightning in years it seems. Thunder longer than that. The models are incredibly boring. There's not even remote chances of anything interesting happening. We have a dry, northwest flow, followed by near record highs, followed by cool and cloudy, followed by warmth. I guess we've just been spoiled the last 2 winters. Since I have been at Texas A&M (2005), it has snowed or iced every single year. I wonder if the trend is broken...

[wxman57]

The 10-day Euro and GFS 500mb pattern does seem quite similar. Low pressure on either coast and high pressure in between. That would mean cool and dry weather continuing through December:

[srainhoutx]

Come on wxman57. You know as well as I do that guidance has been lacking as of late. Heck, we can't even get an agreement on how the EC Snow Storm is going to unfold this weekend...

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
141 PM EST THU DEC 16 2010

VALID 12Z SUN DEC 19 2010 - 12Z THU DEC 23 2010


...INCREASING THREAT OF MAJOR EAST COAST WINTER STORM...
...CONTINUED HEAVY PRECIPITATION INTO THE WEST...

EXTREME HIGH LATITUDE BLOCK TO RETROGRADE TO NCENTRAL CANADA
LOCKING IN TROFS OVER THE ERN PACIFIC AND WESTERN ATLC MID TO LATE
PERIOD. PRIOR TO THAT FAST ZONAL PAC FLOW CONTS TO DRIVE INTO THE
WEST AND EASTERN THRU THE PLAINS WITH A FIRST RELATIVELY AMPLIFIED
SHORTWAVE COMING TOWARDS THE EAST COAST SUNDAY AND ROTATING NWD
WITH A DEEP OFF SHORE STORM FOLLOWED BY BRIEFLY ZONAL FLOW AGAIN
WITH EMBEDDED WAEKER SHORTWAVES COMING ACROSS THE PLAINS TO THE
EAST.

UPDATED MORNING PRELIMS BLENDED THE 00Z UKMET WITH THE 00Z ECMWF
ENS MEAN DAYS 3 TO 5.
THIS KEPT UP A WIND AND COASTAL SNOW THREAT ALONG THE NEW ENGLAND
COAST DAYS 4-5 LATE SUN INTO TUES. OPERATIONAL RUNS OF 00Z ECMWF
AND GFS HAVE REVERSED SOLUTIONS SINCE YTDAS 12Z RUNS WITH THE N
ATLC LOW. LAGGED AVERAGE FORECAST OF LAST 4 RUNS OF BOTH GFS AND
ECMWF PREFERRED KEEPING THE SFC LOW EAST OF THE 00Z OP ECMWF
CLOSER TO THE 00Z ECMWF ENS MEAN AND EASILY CLOSE ENOUGH TO AFFECT
COASTAL NEW ENGLAND.

12Z GFS HAS SWITCHED BACK TO A DEEPER MUCH CLOSER IN LOW CLOSE TO
YTDAS 12Z GFS AND CURRENT 00Z ECMWF TAKING A 980 MB OFF CAPE COD.
THIS SCENARIO FOLLOWS YTDAS HPC PROGS AND THINKING AS MODELS BEGIN
TO CONVERGE ON A MORE AGREED UPON SOLUTION WITH GOOD HPC FORECAST
CONTINUITY FROM YESTERDAY. 12Z UKMET NOW DEEPER AND A BIT FARTHER
OFF WHILE THE OP CMC HAS A 976 MB LOW NEAR THE NORTHEAST BENCHMARK
AT 40/70 WHILE ECMWF HAS ITS 975 MB LOW NEAR BLOCK ISLAND SOUND.
NAVY NOGAPS ALSO DEEP AND CLOSE IN TO CAPE COD. GFS ENS MEANS A
BIT EAST BUT MEAN PCPN SHOWING A SIG PCPN EVENT OVER COASTAL MA.
AFTN PROGS WILL ADJUST SLIGHTLY WEST HAVING A DEEP LOW NEAR THE
NORTHEAST BENCHMARK. MODELS ARE CONVERGING ON THIS SOLUTION WITH
INCREASED FORECASTER CONFIDNECE.

RAPID DEEPENING INDICATED BY 12Z GFS/CMC/00Z AND 12Z ECMWF MODELS
FOLLOWS DYNAMICS AND THE INFLUENCE OF INCREASED BAROCLINICITY DUE
TO THE DE STABILIZATION OVER RELATIVELY WARM OCEAN WATERS FROM THE
RECENT COLD AIR OUTBREAK MEETING. THIS INCREASES THE THREAT OF A
SNOW EVENT ALONG THE MID ATLC COAST FROM EASTERN VA UP THE COAST
AND ESPECIALLY A HEAVY SNOW THREAT FOR COASTAL NEW ENGLAND. SOME
ADDITIONAL WESTWARD ADJUSTMENT MADE FROM THIS MORNINGS PRELIMS
WITH AFTN UPDATED PROGS INCLUDING OPERATIONAL 12Z GFS AND 12Z CMC.
HIGH WIND AND SNOW THREAT NEW ENG COAST LATE SUNDAY AND MONDAY.

NEXT CLIPPER TYPE OF LOW ADJUSTED SOUTHWARD IN ITS TRACK THAN GFS
TO COME THRU THE SRN APPLCHNS AND OFF NC COAST TUES. BLEND OF
GFS/ECMWF ENS MADE WHICH ALSO MATCHES A LAGGED AVERAGE FORECAST
FOR DAYS 6 AND 7.

HVY/EXCESSIVE PCPN THREAT THRU THE PERIOD CONTINUES OVER ALL OF CA
AND INTO THE LOWER GREAT BASIN AND SRN ROCKIES AND SHOULD CONTINUE
BEYOND THIS FORECAST PERIOD WITH TEH CONTINUOS ONSHORE MID LEVEL
FLOW AND OCCASSIONAL FRONTS. 5 DAY LIQUID EQUIV TOTALS EXCEED 6-8
INCHES IN THE SIERRAS/COASTAL RANGES AND SAN DIEGO/LOS ANGELES
RANGES GIVING WEEKLY TOTAL POTENTIALS IN EXCESS OF 10-15 INCHES
OVER FAVORBLE TERRAIN.

CLIPPER TYPE LIGHT PCPN EVENT EXPECTED FROM THE PLAINS INTO THE
MID ATLC REGION MON INTO TUESDAY FOLLOWED BY A RETURN OF
WIDESPREAD BREEZY AND COLD CONDITIONS OVER THE ERN THIRD OF CONUS.

ROSENSTEIN

[wxman57]

Come on wxman57. You know as well as I do that guidance has been lacking as of late. Heck, we can't even get an agreement on how the EC Snow Storm is going to unfold this weekend...

Right, I'm just speaking of the GENERAL flow pattern, not smaller transitory features. The general pattern for the rest of the month seems to favor deep low pressure on either coast with mild temps across Texas and very little precip. That doesn't preclude the possibility of a passing short wave producing some rain here before the month is out. I don't see anything exciting down here through New Year's. Cool and dry. I would expect a pattern change in January/February, to a bit milder temps. More zonal flow but generally dry.

We're thinking of having an office pool to predict on what day IAH will next record 1" or more of rain. I'm thinking April.

[srainhoutx]

I alway like reading Dodge City NWS as they always seem to be ahead of the game regarding changes in the pattern...

I DID NOT MAKE SIGNIFICANT CHANGES TO THE EXTENDED PERIOD AS THERE
IS SLIGHTLY MORE UNCERTAINTY IN THE ENSEMBLE MEMBERS THAN COMPARED
TO YESTERDAY. I WANT TO SEE A FEW MORE RUNS WITH CONSISTENCY BEFORE
I MAKE CHANGES. THE NOTICEABLE CHANGE IS THAT THE OPERATIONAL RUN OF
THE 00Z ECMWF SWINGS THE TROUGH AXIS FURTHER INLAND THAN COMPARED
WITH THE 00Z GFS WHICH MAINTAINS THE TROUGH WELL OFFSHORE. THE 12Z
ECMWF HAS BACKED OFF THE QUICKER SOLUTION SO I AM GOING TO TREAT THE
00Z ECMWF MODEL RUN AS AN OUTLIER. THE NCEP AND ECMWF ENSEMBLE MEANS
ARE IN BETWEEN THESE TWO SOLUTIONS. THIS COULD SPELL OUT BIG
FORECAST CHANGES TOWARDS CHRISTMAS AND AFTERWARD. IF THE 00Z ECMWF
WERE TO VERIFY, WE COULD FINALLY GET SOME INTERESTING WEATHER. IF
THE GFS WERE TO VERIFY, WE WOULD CONTINUE THIS HIGH AND DRY PATTERN
THAT WE HAVE SEEN ALL SEASON LONG.

[srainhoutx]

Hmmm...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... _336.shtml

[harpman]

I can't get it to pull up. What does it show?

[TexasMetBlake]

It won't pull up for me either, but it shows moderate rainfall at that time.

[wxman57]

I fixed the link. It's the 00Z GFS forecasting rain over Texas on New Year's Eve. 06Z GFS has a different solution, however.

[srainhoutx]

The 12Z Operational GFS suggests a Christmas Eve cold frontal passage and a Winter storm brewing across the Southern Rockies into the S Plains. Keep an eye on the Pacific as that large cyclone unravels and spits Upper Level (H5) storms into the West Coast. I've hinted about a pattern change and just perhaps the numerical guidance is 'sniffing' that change out as we head into the long Holiday period. Remember that the guidance has been suggesting a storm or two during that time frame regardless of what the surface temps may show.

[wxman57]

12Z GFS is similar to the 00Z European in bringing a cold front through on Christmas Eve, along with a few showers. Sunny with a high in the mid 50s predicted for Christmas Day.

[srainhoutx]

BTW, why is the Euro now swinging wildly run to run?

It's not just the Euro, Ed. The blocking (extremely -AO) regime is giving the numerical guidance fits in the fast flow La Nina pattern.

[redneckweather]

Reaching for straws I'm afraid srain.

I had a dream last night I was standing in a pasture with my son watching a black as midnight squall line approaching us over the tree line. We joyfully headed inside the house and look at radar and saw white and pink behind the front heading south with the plummeting temperatures! A feeling of euphoria swept over me in my dream!

The freakin alarm then woke me up and I looked outside and started to cry.