OVERVIEW:  Our projection for September was slightly adjusted this week to a near average (-1.0°F to +1.0°F) temperature departure for the month as a whole. This change is largely due to the expectation of slightly below to below average stretches, most notably between September 19th-23rd. October projections were maintained this week for a near average (-1.0°F to +1.0°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 accelerates from this point forward to about a 3.0°F drop per week. The extreme heat is likely behind us, but there will still be some warmer days yet that reach into the 80s over the next couple of days. Climate models have continued to suggest an up-and-down temperature pattern in October, which balances any slightly below and slightly above periods to near average.
   
• The Madden-Julian Oscillation (MJO) is currently in the Circle of Death (COD) or NULL phase, and is expected to venture into a weak phase 8 signal over the weekend, then quickly into a weak phase 1 signal early next week before collapsing back into the COD later in the week. 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. In fact, as of today, this is the longest we’ve gone without an Atlantic Basin hurricane in since 1966 in the modern satellite era, which is pretty remarkable.

   

• A composite average of the SST departures in the ENSO regions places it in moderate to strong El Niño territory currently. 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 +3.0°C. The eastern regions of Niño 3 (east-central Pacific) is currently +3.8°C, and Niño 1+2 region (near the Peruvian coast) is at an astounding +5.0°C as of September 14th. The current El Niño Summer is likely to be followed by a near-record strong El Niño Fall, and is currently East-based.

   

Average high temperatures are currently in the 75-79°F range from north to south across our coverage region, which is about 2°F lower than at this point last week. The drop off in temperatures will now accelerate downward from this point forward to 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 below average temperatures listed for the September 21st-23rd period features highs in the upper 60s to lower 70s, coming at a time when average highs are in the middle 70s. Use the average highs/lows chart below providing transparency for what average temperatures are expected to be at each corresponding location through November 1st.

Our September projection was slightly adjusted this week to a near average (-1.0°F to +1.0°F) temperature departure to account for the cooler stretches over the next week to ten days. October projections were maintained this week for a near average (-1.0°F to +1.0°F) temperature departure using long term climate guidance and global observation trends.