MET Office - NAO Prediction

From the UK Met Office...
"The figure below shows that the predicted winter NAO index for 2007/8 is weakly negative at -0.05 with a standard error of ±1.0. The near zero amplitude of the predicted index relative to the error bar means that the NAO prediction provides little signal for below- or above-normal European winter temperatures or precipitation. However, the prediction is consistent with a cooler, drier winter over northern Europe as a whole than experienced in winter 2006/7, when the observed index was +1.1."


The model does an OK job forecasting inter-annual variations...but not so much for an upcoming season. Its correlation coefficient (R) is an anemic 0.45. Enough to demonstrate some skill but not high enough to hint at which way it/s heading next.

Here/s the model/s loading pattern. The anomaly tri-pole along NOAM/S EC and the Saragossa Sea dipole are associated with anomalies @ 500 mb and a positive NAO.


Here/s the model/s SSTAs for this year. A strong signal NAO won/t be strong positive.


Forecasts for the previous two years/s have been good for sign and magnitude...however...past performance does not guarantee future rate of return. The error bars suggest 1) NAO won/t be stronger than last year and 2) the index has a 50/50 chance of going either way relative to zero.

Snow International

Global snow reporting from snow-forecast.com Updated weekly.

From their latest post...

North America
==========
"Over the past few days, our snow alert system has been busy sending
warnings of new snow for the Canadian Rockies - the first time this
season. With a strong La Nina, we would expect a steady stream of
Pacific storms pouring into the Pacific NW. This is just what the
forecast for the next 7 days shows with Whistler bearing the full
brunt on Saturday night and then again on Tuesday and yet again on
Friday. Too mild for snow at resort level this close to the coast and
this early in the season, but above mid-station we expect to see the
accumulation of another 50cm of fresh snow by Wednesday. As these
weather systems push deep into the continent on a NE track, many
resorts in the Pacific NW and the northern Rockies will enjoy
excellent early season snowfalls."

More...

Beware the Three-headed Dog

"...[T]hree major phenomena, which he likened to a "three-headed dog", influenced Australia's rainfall: El Nino events, the Indian Ocean Dipole, and the Southern Annular Mode, a weather pattern in the Southern Ocean..."

woof!

October's ENSO Anomaly Forecast - Winter '07 - '08

Latest CFS forecast for ENSO Region 3.4 SST anomaly of ~-1.6°C continues trend from previous model runs for La Nina conditions to be well established this winter. Each run has been stronger than the last. The current forecast for a 'strong' La Nina reflects a 1°C difference from last summer/s 'weak' forecast.


Previous DJF forecast values (°C)
April -0.6
May -0.6
June -0.8
July -0.9
August -1.1

Latest monthly temperature and precipitation anomalies reflect the model/s La Nina forecast for warm and dry in the SE.

7th Annual Season-total Snowfall Forecast Contest

NE.Wx/s annual ‘Season-Total Snowfall Forecasting Contest’ is your absolute best...biggest...and probably ONLY chance to be recognized for your long-range forecasting acumen; recognition you so richly deserve.

Not only that...but if you win the Contest...you get a copy of "The Snow Booklet"...by Nolan J. Doesken and Arthur Judson.

What other incentive could you possibly want to enter the Contest?

The Contest is open to any and all of the following:
Amateur and professional forecasters; broadcasters with or without trained Seals; all weather-biz types and wanna-bees; wish-casters...astrologers and other commonly recognized classes of dreamers; Pollyannas or Cassandras...registered Nostradamists...non-violent megalomaniacs...woolly-bear caterpillars or their agents; pest detectives...NE.Wx NG regulars and lurkers; refugees from EUSWx or StormVista...and of course... meteorologists.

Trolls...goats...hat3-lsiters...and psests need not apply.

The reigning NE.Wx ‘Season-Total’ Snowfall Forecasting Champ-een is Raven2001.

Forecast element: sum-total season snowfall
Forecast period: December 1, 2007 through March 31, 2008
Verification: NWS preliminary climate reports (CLM or F6)

Deadline: Friday, November 30, 2007 @ 11:59 PM EST

Station list at the website.

WSI Energycast - OND

In the NE...
October - Colder than normal
November - Warmer than normal
December - Colder than normal

"According to WSI seasonal forecaster Dr. Todd Crawford, “The La Nina event continues to slowly strengthen and play a dominant role in temperature patterns, primarily via modulation of tropical convection patterns and their subsequent downstream impacts in the US. Typically, in the eastern US, La Nina means a warm October and a cold December, with the transition occurring in November. While we feel that December will indeed be cold in the East, the current ocean temperature patterns in the northern Pacific suggest that the early fall warmth may not be as certain as the La Nina signal suggests.” "

More...

HARD Winter Follows HOT August

Apparently...if it/s unusually warm the first week of August...a hard winter/s a/comin/.

"If the first week in August is unusually warm,
The coming Winter will be snowy and long."

Must have missed class the day that old chestnut was presented!

How can an 'unusually warm' first week of August be quantified? NWS field manuals of old described 'mild' temperatures as departures 5-10 °F above normal. 'Hot' was a departure of 10 or more.

'Hot' seems to lend itself more to 'unusually warm' than does 'mild.' If that/s the case...then a station would need a total anomaly of 70°F to qualify as 'unusually warm.'

So...what/s in store this winter according to folklore for NE and the M-A regions? The bar chart shows 7-day total temperature anomalies for NEWxSFC stations.


The 'rule' cannot be expressly applied b/c there were no stations where the 7-day anomaly total was 70°F or higher. IAD and BWI were most 'unusually warm' with 49 and 44°F anomalies... respectively.

The average station temperature anomaly was ~31 °F. The 90th percentile station temperature anomaly came in @ 41°F...which includes IAD...BWI...ACY...and RIC.

So...there it is. If indeed...a hot August ==> long, snowy winter...then this year/s action center will be found in a tightly constricted corridor along the M-A/s coastal plain.

ENSO Anomaly Forecast - Winter '07 - '08

Latest CFS forecast for ENSO Region 3.4 SST anomaly of ~-1.1°C continues trend from previous model runs for La Nina conditions to be well established this winter.


Previous DJF forecast values (°C)
April -0.6
May -0.6
June -0.8
July -0.9

Monthly temperature and precipitation anomalies reflect the model/s La Nina forecast for warm and dry in the SE.

Farmers/ Almanac 07-08 Winter Outlook - Atlantic Corridor

"Winter will be about a degree milder than normal, on average. Precipitation will be a bit above normal across southern New England and eastern Long Island and below normal elsewhere. Snowfall will be near to slightly below normal, with the snowiest periods in mid-December, mid- to late January, and mid-February. The coldest temperatures will occur in early and late December, mid-January, and early and mid-February."

More...

sCAST Money Shot

Note the negative correlation (increased snow cover associated with decreased temperature) between Siberia and the cold signal across the OH / TN River Valleys and ern GL regions of the upper M-W.