WFO (Buffalo) AFD is very interesting....

[yoda]

LOOKING AT THE EXTENDED (SECOND WEEK OF DEC) FORECAST...IT STILL
LOOKS AS IF TEMPERATURES WILL AVERAGE ABOVE NORMAL FOR WESTERN AND
NORTH CENTRAL NEW YORK. THE CPC 6 TO 10 AND 8 TO 14 DAY TEMP OUTLOOK
IS CALLING FOR ABOVE NORMAL TEMPS...AND TELECONNECTION ENSEMBLE
MODELS ARE IN GENERAL AGREEMENT. LIKE THE PAST FEW DAYS...THERE IS A
LARGE SPREAD AMONGST THE MEMBERS OF BOTH THE PNA AND NAO ENSEMBLES
WITH THE FORECASTS FAVORING A TROUGH IN THE WESTERN UNITED STATES.

AN INTERESTING STUDY BY SFM HERE IN THE OFFICE HAS ALSO SHOWN A VERY
STRONG CORRELATION BETWEEN HAVING VERY LOW SNOWFALL IN NOVEMBER TO
HAVING 'MILD' WINTERS. THIS WOULD BE IN LINE WITH ANOTHER IN-HOUSE
STUDY THAT REVEALS RATHER MILD WINTERS DURING COMBINED WEAK EL NINO/
POSITIVE NAO COMBINED EVENTS. A WEAK EL NINO HAS BEEN IN PLACE...
BRITISH FORECASTERS ARE CALLING FOR PREDOMINANTLY POSITIVE NAO
CONDITIONS FOR THE WINTER MONTHS.

http://www.erh.noaa.gov/buf/products/BUFAFDBUF1.html


Is that true? I did not know if that I was, so I was wondering if a few pro mets or others on here could expand on what is being said here. Also, don't the British use a different NAO scale?

[verycoolnin]

A positive NAO does correlate with mild winters in the east. I'm not really sold on "low snowfalls in November correlate with mild winters" though.

[Wnghs2007]

This is a bunch of Baleogni. The Negative Nao will happen most of the winter long. Look at the SSTA patter already starting to evolve.

[donsutherland1]

Yoda,

Very clearly, very low snowfall in/through November in Buffalo correlates strongly to a warmer-than-normal winter there. For example, since monthly temperature data has been available since 1940, there have been 13 winters where cumulative snowfall through November has come to less than 2". Just one of those winters came out colder than normal (1981-82).

Although such a slow start to the seasonal snowfall might strongly indicate a warmer than normal winter in Buffalo, it does not necessarily mean that the winter will see less snowfall than normal.

Instead, in Buffalo, the rest of the winter will truly "remember" December. In those cases, if December sees 20" or more snowfall, then the winter generally proved snowy (100" or more snowfall).

Since seasonal snowfall records have been kept beginning in 1884-85, there have been 21 winters where cumulative snowfall had come to less than 2" at the end of November. Here's what happened based on December snowfall:

Less than 10":
• 0/8 (0.0%) saw 100" or more snowfall
• Average seasonal snowfall: 52.6"

10"-19.9":
• 2/7 (28.6%) saw 100" ore more snowfall
• Average seasonal snowfall: 76.0"

20" or more:
• 4/6 (66.7%) saw 100" or more snowfall
• Average seasonal snowfall: 106.9"

In terms of NAO-PNA combinations (using the December-March averages) and 1950-51 through 2003-04 when data for the global indices was regularly reported, the following held true for seasonal snowfall and frequency of seasons with 100" or more snowfall in Buffalo:

Code: Select all

NAO   PNA   Snowfall   100" or more
+     +     91.3"      6/13 (46.2%) seasons
+     -     84.8"      3/14 (21.4%) seasons
-     +     117.2"     7/11 (63.6%) seasons
-     -     94.7"      6/16 (37.5%) seasons


Finally, there's even more to the proverbial story than just the above table. When I have some time to post later today (probably tonight), I'll provide the rest of the story...

[Wnghs2007]

Yoda,

Very clearly, very low snowfall in/through November in Buffalo correlates strongly to a warmer-than-normal winter there. For example, since monthly temperature data has been available since 1940, there have been 13 winters where cumulative snowfall through November has come to less than 2". Just one of those winters came out colder than normal (1981-82).

Although such a slow start to the seasonal snowfall might strongly indicate a warmer than normal winter in Buffalo, it does not necessarily mean that the winter will see less snowfall than normal.

Instead, in Buffalo, the rest of the winter will truly "remember" December. In those cases, if December sees 20" or more snowfall, then the winter generally proved snowy (100" or more snowfall).

Since seasonal snowfall records have been kept beginning in 1884-85, there have been 21 winters where cumulative snowfall had come to less than 2" at the end of November. Here's what happened based on December snowfall:

Less than 10":
• 0/8 (0.0%) saw 100" or more snowfall
• Average seasonal snowfall: 52.6"

10"-19.9":
• 2/7 (28.6%) saw 100" ore more snowfall
• Average seasonal snowfall: 76.0"

20" or more:
• 4/6 (66.7%) saw 100" or more snowfall
• Average seasonal snowfall: 106.9"

In terms of NAO-PNA combinations (using the December-March averages) and 1950-51 through 2003-04 when data for the global indices was regularly reported, the following held true for seasonal snowfall and frequency of seasons with 100" or more snowfall in Buffalo:

Code: Select all

NAO   PNA   Snowfall   100" or more
+     +     91.3"      6/13 (46.2%) seasons
+     -     84.8"      3/14 (21.4%) seasons
-     +     117.2"     7/11 (63.6%) seasons
-     -     94.7"      6/16 (37.5%) seasons


Finally, there's even more to the proverbial story than just the above table. When I have some time to post later today (probably tonight), I'll provide the rest of the story...

\


Good post. But I do believe the NAO will negative below 0 after mid jan for most of the winter.

[donsutherland1]

For the proverbial rest of the story...

Earlier, I had posted the following table concerning Buffalo's seasonal snowfall:

Code: Select all

NAO   PNA   Snowfall   100" or more
+     +     91.3"      6/13 (46.2%) seasons
+     -     84.8"      3/14 (21.4%) seasons
-     +     117.2"     7/11 (63.6%) seasons
-     -     94.7"      6/16 (37.5%) seasons


It turns out that, for two and possibly three situations, the SSTs in ENSO Region 1+2 may play a big role in shaping the downstream synoptic setup.

Here are the combinations:

NAO +; PNA +
•Region 1+2: 24.5°C - 25.0°C: 6/7 (85.7%) seasons had 100" or more snowfall; average snowfall: 88.6"
• Remainder of cases: 0/6 (0.0%) seasons had 100" or more snowfall; average snowfall: 81.0"

NAO +; PNA -
•Region 1+2: 24.5°C - 25.25°C: 3/7 (42.8%) seasons had 100" or more snowfall; average snowfall: 108.2"
• Remainder of cases: 0/7 (0.0%) seasons had 100" or more snowfall; average snowfall: 71.6"

NAO -; PNA +
•Region 1+2: 24.5°C - 25.75°C: 7/7 (100.0%) seasons had 100" or more snowfall; average snowfall: 140.6"
• Remainder of cases: 0/4 (0.0%) seasons had 100" or more snowfall; average snowfall: 76.1"

NAO -; PNA -
•Region 1+2: 23.75°C - 25.00°C: 6/10 (100.0%) seasons had 100" or more snowfall; average snowfall: 99.2"
• Remainder of cases: 0/6 (0.0%) seasons had 100" or more snowfall; average snowfall: 87.4"

When the PNA averages negative, it appears that the SSTs in ENSO Region 3 might be a better overall predictor than the SSTs in Region 1+2.

NAO +; PNA -
•Region 3: 25.55°C - 25.85°C: 3/3 (100.0%) seasons had 100" or more snowfall; average snowfall: 118.7"
• Remainder of cases: 0/11 (0.0%) seasons had 100" or more snowfall; average snowfall: 75.6"

NAO -; PNA -
•Region 3: Below 26.25°C: 5/11 (45.5%) seasons had 100" or more snowfall; average snowfall: 98.6"
• Remainder of cases: 1/5 (20.0%) seasons had 100" or more snowfall; average snowfall: 86.3"

[Wnghs2007]

For the proverbial rest of the story...

Earlier, I had posted the following table concerning Buffalo's seasonal snowfall:

Code: Select all

NAO   PNA   Snowfall   100" or more
+     +     91.3"      6/13 (46.2%) seasons
+     -     84.8"      3/14 (21.4%) seasons
-     +     117.2"     7/11 (63.6%) seasons
-     -     94.7"      6/16 (37.5%) seasons


It turns out that, for two and possibly three situations, the SSTs in ENSO Region 1+2 may play a big role in shaping the downstream synoptic setup.

Here are the combinations:

NAO +; PNA +
•Region 1+2: 24.5°C - 25.0°C: 6/7 (85.7%) seasons had 100" or more snowfall; average snowfall: 88.6"
• Remainder of cases: 0/6 (0.0%) seasons had 100" or more snowfall; average snowfall: 81.0"

NAO +; PNA -
•Region 1+2: 24.5°C - 25.25°C: 3/7 (42.8%) seasons had 100" or more snowfall; average snowfall: 108.2"
• Remainder of cases: 0/7 (0.0%) seasons had 100" or more snowfall; average snowfall: 71.6"

NAO -; PNA +
•Region 1+2: 24.5°C - 25.75°C: 7/7 (100.0%) seasons had 100" or more snowfall; average snowfall: 140.6"
• Remainder of cases: 0/4 (0.0%) seasons had 100" or more snowfall; average snowfall: 76.1"

NAO -; PNA -
•Region 1+2: 23.75°C - 25.00°C: 6/10 (100.0%) seasons had 100" or more snowfall; average snowfall: 99.2"
• Remainder of cases: 0/6 (0.0%) seasons had 100" or more snowfall; average snowfall: 87.4"

When the PNA averages negative, it appears that the SSTs in ENSO Region 3 might be a better overall predictor than the SSTs in Region 1+2.

NAO +; PNA -
•Region 3: 25.55°C - 25.85°C: 3/3 (100.0%) seasons had 100" or more snowfall; average snowfall: 118.7"
• Remainder of cases: 0/11 (0.0%) seasons had 100" or more snowfall; average snowfall: 75.6"

NAO -; PNA -
•Region 3: Below 26.25°C: 5/11 (45.5%) seasons had 100" or more snowfall; average snowfall: 98.6"
• Remainder of cases: 1/5 (20.0%) seasons had 100" or more snowfall; average snowfall: 86.3"

Thanks again Don.