EPIC WEATHER/CLIMATE SYNOPSIS

CLIMATE CONDITIONS:

The equatorial Pacific SSTs and surface winds remain very much near normal.  
Convective activity in the west Pacific is slightly more active than normal for this time of 
the year.  An oceanic Kelvin wave generated by wind activity in the west Pacific continue 
to propagate eastward across the basin and is now located near 100W (Image 1).  SSTs in the east 
Pacific ITCZ region remain slightly higher than normal (Image 2).  Even small anomalies within the 
area of warmest SSTs, however, can have a large impact on convective activity.

SYNOPTIC CONDITIONS:

S Chantal is just east of the Yucatan.  It is forecast to move west northwest over the 
next few days with little further northward movement.  Upper trop. Water vapor imagery 
shows the EPAC to be extremely dry with dry air extending up to 6N and from 70W-
105W along the equator (Image 3).  Convective activity in the EPAC ITCZ is relatively suppressed.  
These dry and suppressed conditions may be related to the negative phase of an 
atmospheric easterly Kelvin wave.  The positive phase of this wave was apparent in some 
of the SSMI hovmollers.  A large MJO is in the west Pacific and is expected to propagate 
fairly far east (Image 4).  With the subsurface primed with anomalously warm water and the west 
Pacific wind burst activity high, are we seeing a set-up for a rapid change to warm 
conditions?  Only time will tell.  Most models only forecast a modest warm event, but 
synoptic conditions are set for a possible rapid switch by later in the Fall (i.e., later in 
October or November…you heard it here first…).