OVERVIEW:  The month of May projections were adjusted this week to a near to slightly below average (-0.0°F to -2.0°F) temperature departure for the month as a whole, with the cooler than average temperatures during the first half of the month only somewhat offset by the expected warmer periods during the 2nd half of May. 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 moves in with summerlike temperatures this weekend through midweek next week. Following this period is 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 Maritime Continent phase 4. The GEFS-extended expects a re-emergence into phase 5 in about a week from now, and phase 6 and 7 toward the end of this month and heading into early June. This differs from most guidance that instead keeps tropical forcing effects muted in the COD, with a possible movement into phase 7 toward the end of May. A propagation through the COD would allow other teleconnections to run the pattern, as well as promote some temperature moderation as will be the case this week.

   

• 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, whereas the Niño 3.4 region (east-central Pacific) is at +1.2°C. The eastern regions of Niño 3 (east-central Pacific) is currently +1.4°C, and Niño 1+2 region (near the Peruvian coast) is at +1.8°C as of May 13th. 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 72-74°F range from north to south across our coverage region, which is about 1-2°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 21st-24th features highs in the upper 60s to low 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 July 1st.

May projections were adjusted this week to a near to slightly below average (-0.0°F to -2.0°F) temperature departure for the month as a whole, with the most notably below average temperatures occurring during the first half of the month, balanced only somewhat by warmer risks during the 2nd half of May. 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.