OVERVIEW:  Our projection for October was slightly adjusted this week to a near average (-1.0°F to +1.0°F) temperature departure for the month as a whole, with the expectation of cooler than average stretches balancing the milder stretches during the 2nd half of this month. November projections were also adjusted this week to a near to slightly above average (0.0°F to +2.0°F) temperature departure, using long term climate guidance and global observation trends.

• Seasonal changes are going to be become more noticeable in the weeks ahead as we continue to lower average highs/lows, and that downward process is now about a 3.0°F drop per week. The extreme heat is likely behind us, but the first half of October is overall at least slightly above average across the region. Ensembles and climate models continue to suggest a balance between cooler and slightly milder periods during the 2nd half of October. This allows the month as a whole to finish near average. The current expectation for November is for temperatures to be near to slightly above average as a whole. 
   
• The Madden-Julian Oscillation (MJO) is currently in a very weak phase 1 signal, and is expected to quickly collapse into the Circle of Death (COD) or NULL phase this weekend. Once we reach the 4th week of October, both the GEFS extended and EPS weeklies are suggesting an Indian Ocean propagation of phases 2/3, which generally signals milder conditions a few weeks later – supporting the slightly milder risks at times in our November outlook. Hurricane activity should remain limited at best with a strong El Niño increasing Atlantic shear despite reaching the peak of Atlantic hurricane season September 10th. Until Isaias became a hurricane last week, it was the longest we’ve gone without an Atlantic Basin hurricane since 1966 in the modern satellite era, which is pretty remarkable. It is also the longest stretch in the pre-satellite era since 1914… a season where no hurricanes were present, or at least none that were documented.

   

• A composite average of the Sea Surface Temperature Anomalies (SSTa) in the ENSO regions places it in strong El Niño territory currently. The following are Coral Reef Watch Sea Surface Temperature Anomaly values referenced in this context. From west to east across the Pacific, the Niño 4 (west-central Pacific) is currently the “coolest” region at +1.1°C, whereas the Niño 3.4 region (east-central Pacific) is currently at +3.2°C. The eastern regions of Niño 3 (east-central Pacific) is currently +4.2°C, and Niño 1+2 region (near the Peruvian coast) is at an astounding +5.4°C as of October 14th. A near-record strong El Niño Fall is likely to continue and peak in November, and currently East-based.

Average high temperatures are currently in the 63-69°F range from north to south across our coverage region, which is about 3°F lower than at this point last week. The drop off in temperatures will continue throughout Fall at about a 3°F per week drop. Any above or below average stretches listed in the outlook will be relative to seasonal norms at that time, and it is important to note that cooler/warmer periods will be relative to the time of year we are talking about. For example, the near to slightly above average temperatures listed in the October 23rd-27th period features highs in the mid to upper 60s, coming at a time when average highs are in the low to mid 60s. Use the average highs/lows chart below providing transparency for what average temperatures are at each corresponding location through December 1st.