Post by thibodauxwx on Jan 17, 2014 11:49:12 GMT -6
from LArry Cosgrove:
Larry Cosgrove
Since there appears to be some debate going on about the intensity and duration of the Arctic air mass over the next two weeks (although, given the numerical model evidence, I cannot understand why...), I ran a comparison test to see how the current 500MB longwave configuration matches up with past years.
January 1 - 15, 1994 is a pretty decent match for the first 15 days of 2014. Not perfect, mind you, but you can see the strong -EPO and -AO signals and central Atlantic Ocean ridging with impressive mid-continent trough. Cold air was quite intense in the last two weeks of January 1994, especially the Midwest, Appalachia, and the Northeast. This set-up tells me that the 12z Jan 17 GFS model suite is probably correct in its 6 - 10 and 11 - 15 day forecasts. At least in terms of temperature.
The tougher call is for storminess. All of the schemes have handled the southern branch disturbance sets very poorly this winter. You can clearly see the tendency for energy and moisture around the Hawaiian Islands then and now. A new moist feed is shaping up near Baja California. If the analog holds true, an important storm will track across northern mexico into the western Gulf Coast, then up along or just off of the Eastern Seaboard. With important snow and ice consequences at some juncture between now and the end of the month.
So while California misses out on needed rainfall and the West is (mostly) mild (especially the Pacific Northwest), the southern and eastern tiers of the U.S. may be seeing the apex of winter weather. Before a warming trend sets in at the start of February.
And, no Super Bowl weather predictions just yet...
Larry Cosgrove
Since there appears to be some debate going on about the intensity and duration of the Arctic air mass over the next two weeks (although, given the numerical model evidence, I cannot understand why...), I ran a comparison test to see how the current 500MB longwave configuration matches up with past years.
January 1 - 15, 1994 is a pretty decent match for the first 15 days of 2014. Not perfect, mind you, but you can see the strong -EPO and -AO signals and central Atlantic Ocean ridging with impressive mid-continent trough. Cold air was quite intense in the last two weeks of January 1994, especially the Midwest, Appalachia, and the Northeast. This set-up tells me that the 12z Jan 17 GFS model suite is probably correct in its 6 - 10 and 11 - 15 day forecasts. At least in terms of temperature.
The tougher call is for storminess. All of the schemes have handled the southern branch disturbance sets very poorly this winter. You can clearly see the tendency for energy and moisture around the Hawaiian Islands then and now. A new moist feed is shaping up near Baja California. If the analog holds true, an important storm will track across northern mexico into the western Gulf Coast, then up along or just off of the Eastern Seaboard. With important snow and ice consequences at some juncture between now and the end of the month.
So while California misses out on needed rainfall and the West is (mostly) mild (especially the Pacific Northwest), the southern and eastern tiers of the U.S. may be seeing the apex of winter weather. Before a warming trend sets in at the start of February.
And, no Super Bowl weather predictions just yet...