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Temperature Snapshot:
• Northeast: Near normal
• Mid-Atlantic: Near normal
• Southeast: Near normal
• Great Lakes: Near normal
• Northern Plains: Above normal
• Central Plains: Above normal
• Southern Plains: Near normal
• Western third of the United States: Near normal but somewhat above normal in the Pacific Northwest
Precipitation Snapshot:
• Northeast: Near normal
• Mid-Atlantic: Near normal
• Southeast: Near normal
• Great Lakes: Near normal
• Northern Plains: Near normal
• Central and Southern Plains: Somewhat below normal
• California/Oregon: Above normal
• Pacific Northwest: Somewhat below normal to near normal
Seasonal Snowfall Estimates:
Based on snowfall tendencies during weak to moderate El Niño events coupled with a warm anomaly in ENSO Region 1+2, odds favor lesser snowfall amounts in some of the cities that have fared very well in recent years in the northern Mid-Atlantic region. Eastern New England seems poised for average to above average snowfall. Parts of the Midwest should do better this winter with Chicago probably approaching or exceeding 40”. A cooler winter in the Southeast could allow for Richmond to enjoy seasonal snowfall in excess of 10”. However, in the Plains States, it appears that the snow dearth that has yielded harvests of barren ground to such cities as St. Louis will likely continue.
What is particularly intriguing is the persistence of warm anomalies in the Gulf of Mexico. This might bode well for the possible development of that scarce winter beast—thought by some to be extinct—the Miller A storm. With an active southern jet courtesy of a weak to moderate El Niño, there should at least be some opportunities for better snowfall in the Lower Mid-Atlantic region than has been the case last winter. Of course, sufficiently cold air will have to be present for the storminess.
Baltimore: 15”-25”
Boston: 45”-55”
Buffalo: 85”-95”
Burlington: 75”-85”
Chicago: 35”-45”
Detroit: 35”-45”
New York City: 20”-30”
Philadelphia: 17”-27”
Pittsburgh: 35”-45”
Providence: 40”-50”
Raleigh: 2”-5”
Richmond: 10”-15”
St. Louis: 12”-17”
Washington, DC: 12”-17”
Additional Discussion:
Over the past 6 months, the Multivariate ENSO Index (MEI) has most closely resembled that of 1951, 1963, 1976, 1979, 1986, and 2004. The following winters were, on average, warmer than normal in the Northern Plains and near normal elsewhere in terms of temperatures:
However, the composite anomalies have differed markedly in terms of the placement of anomalies over the past season. This hints that other factors have been outweighing the weak El Niño in terms of driving the weather patterns so far. However, the opening days of October have featured anomalies that are more in line with the warm anomalies being centered across the Plains States, so some of the difference might be attributed to a lag between the development of the MEI and the resulting weather.
So far, in terms of 3-month anomalies, both the June-August and July-September periods have closely resembled those for 2002.
The PDO will likely average > 0. Since 1900, in the years when the PDO averaged 0 to +1.00 in the June-July period and then fell < 0 in August, it snapped back to average > 0 in 8/9 (89%) cases. At the same time, in 14/19 (74%) cases after it had fallen by -0.50 to -1.50 in the June-July period as occurred this year, it rebounded to > 0 if it averaged >0 in the June-July period. Taking into consideration that the PDO is likely in the transition period toward a negative cycle but is not yet in such a cycle, I believe odds favor a return to > 0 levels. However, that might not happen until January or perhaps February. As a result, the first third to perhaps half of the winter might well see a PDO-.
Among the years that saw the MEI most closely resemble that of 2006 and saw a PDO > 0 in the winter, the warm anomaly in the Northern Plains and a cool anomaly in the East were especially pronounced:
In terms of years that saw a weak to moderate El Niño peak no later than November-December-January, the East tended to be cool while the central and southern Plains tended to be warm:
However, a prolonged PDO- tended to eliminate the cool anomalies in the East. Given what I expect to be a possible delayed return to the PDO+, I’ll err on the side of conservatism with regard to possible cool anomalies in the East.
The latest ensemble means from IRI suggest cool anomalies on the East Coast and southern Plains: http://iri.columbia.edu/forecast/climat ... merica.gif
The CFS Model is indicating cool conditions in the East/Southwest and warm conditions in the Central and Northern Plains out to the Pacific Northwest: http://www.cpc.ncep.noaa.gov/products/p ... T2mSea.gif
Historic Tidbit: The Great January 1818 Norfolk Snowstorm
On January 30-31, 1818, a storm brought a tremendous snowfall to southern Virginia. At Norfolk, the accumulation likely rivaled or exceeded the modern record of 18.6” set on December 26-27, 1892. High winds also blew the snow into sizable drifts. The February 2, 1818 edition of the Norfolk Herald published the following account:
We question whether a N. Englander, who witnessed the weather we had here on Saturday [January 31], would venture to depreciate it as inferior to what he had been used to at home. It is certain that those who have a long experience of our climate, cannot recollect a more inclement day. The snow commenced falling on Friday afternoon [January 30], and did not cease until a late hour on Saturday night. During the greater part of the time, the wind blew with such violence, and the air was so thickened by the falling snow, that not a vessel of any description dared to hoist sail.—Even the Hampton mail boats, which have braved the thunder of a British squadron [during the War of 1812], as the awful threatenings of the storm, shrunk from their accustomed duties, and left us as much in the dark with respect to news, as we were on account of the weather…
The snow drifted in banks wherever the wind blew in a current; many of these banks are 4 or 5 feet in depth, while the courses swept by the wind are nearly bare. On a level, the snow would probably average 18 or 20 inches—a greater depth than has been known here for 20 years past. The streets, though the do not wear a somber appearance are by no means so gratifying to contemplate as the inhabitants could wish; and except w[h]ere avenues have been cleared, it is difficult to cross them.
