The WPO is forecast to be significantly negative for the last week of the month. The advertised orientation of the ridge can help offset the -PNA some, and the EPO is forecast to be only slightly positive before rising some the last few days of the month. AO and NAO look to be negative, but not severely. If all this verifies then the only 'unfavorable' index is the PNA, which is forecast to trend less negative from the 20th through the end of the month.