Strong Positive Phase PNA Pattern to Develope over Eastern Pacific…..Coupled Air Sea Climate Models….Back Peddle on Break Through of Westerlies For Ca……Dry Pattern Likely to Continue……
Monday January 30, 2012
Posted at 7:46 am by Howard
Pattern Change show Strong Amplification expected in the westerlies resulting in Strong Blocking ridge over west coast next weekend, north into Canada with high latitude bloc extending will into Arctic later during week 2. Although the southern branch splits main effects probably better for SW CONUS. So wet weather for Ca looking pretty unlikely for California…..well into February. Position of Upper Ridge/Block likely to bring period of very mild weather for February as well.
Here is the word from NCEP for this morning…..
1. The MJO is forecast to contribute to enhanced convection across parts of the western Pacific, northeast Australia and the South Pacific Convergence Zone (SPCZ) during the next two weeks. Suppressed convection is favored for the Indian Ocean over the period.
2. For the U.S., the current and forecast phases of the MJO favor a tendency for a “positive PNA pattern” in coming weeks with enhanced chances for below-normal temperatures in the eastern U.S..
3. “Later” as the MJO enters the western hemisphere, there is a tendency for stronger jet streams to develop. “There is potential for a ridge in the west to be undercut”, returning wet conditions to the west, and also enhanced moisture is more likely across the southern tier of the U.S.
The net results…
If we get the breakthrough it will take longer….Possibly around or beyond 2nd week of February.
Reference Glossary of Weather Terms
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