OVERVIEW:  The month of May projections were maintained this week for a near to slightly below average (-0.0°F to -2.0°F) temperature departure for the month as a whole. Cooler than average temperatures during the first half of the month we largely offset by the very hot temperatures over several days within the past week, but the remainder of the month will be below average with just a few exceptions. Projections for the month of June were maintained this week to a near average (-0.5°F to -0.5°F) temperature departure, using long term climate guidance and global observation trends.

• Strong ridging moved in over the past week, which not only resulted in well above average and summer temperatures in the 90s, it also completely offset the cooler than average temperatures from the first half of May and brought most areas back to near average and in some cases, very slightly above average month-to-date. Very cool temperatures over the holiday weekend will likely send most areas very slightly below average by month’s end when the dust settles. Following this month is a rather normal/average pattern that is sustainable throughout most of June. Although there can be shorter term temperature fluctuations above or below average, the larger picture of June is more likely to follow the early Summer El Niño paradigm.
  
  
• The Madden-Julian Oscillation (MJO) is currently in the Circle of Death (COD) or NULL phase bordering the Maritime Continent. Most guidance expects a re-emergence into phase 6 briefly early next week, then phase 7 toward the end of this month, and maintaining there through the first 3 weeks of June. This propagation would suggest a general fast-moving pattern with near average temperatures as we transition from ENSO neutral to El Niño.
  
  

• A composite average of the SST departures in the ENSO regions places it in El Niño territory currently. From west to east across the Pacific, the Niño 4 (west-central Pacific) is currently +1.1°C, and the Niño 3.4 region (east-central Pacific) is also at +1.1°C. The eastern regions of Niño 3 (east-central Pacific) is currently +1.2°C, and Niño 1+2 region (near the Peruvian coast) is at +1.9°C as of May 20th. The threshold for El Niño begins at +0.5°C as a composite average of the ENSO regions, and although not officially declared by the CPC, it is the expected transition, and an El Niño Summer and Fall will follow.
  
  

Average high temperatures are currently in the 74-76°F range from north to south across our coverage region, which is about 2°F higher than at this point last week. Climatological annual maximum temperatures will be achieved in July. 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 slightly below average temperatures listed for May 29th-31st features highs in the low to mid 70s, coming at a time when average highs are in the upper 70s. Use the average highs/lows chart below providing transparency for what average temperatures are expected to be at each corresponding location through July 1st.

May projections were maintained this week for a near to slightly below average (-0.0°F to -2.0°F) temperature departure for the month as a whole, with the expectation of some cooler risks 5 of the 8 remaining days of May… especially this weekend. The projections for the month of June were maintained this week for a near average (-0.5°F to +0.5°F) temperature departure, using long term climate guidance and global observation trends.