Guidance continues to indicate an unusually intense PV-esque lobe orienting in the vicinity of Baffin Island during the midrange time period that will most likely herald a substantially cooler-than-normal pattern for N QC and Labrador as it does so.

00z ECMWF/GFS/CMC 500mb height anomalies, days 8-10:

test8

Some flattening of the predominant western/central mean ridge also looks to take place which should at least temporarily blunt the warmth in those regions beyond this next short-term hot spell.

00z EPS 500mb height anomalies, days 1-5:

ecmwf-ens_z500aMean_namer_1

Days 6-10:

ecmwf-ens_z500aMean_namer_6

The extent to which the prevailing pattern is able to re-establish itself into the extended range remains to be seen but a new set of Euro weeklies tonight will be of assistance in gaining some insight.


ENSO-neutral conditions roll on as per the latest update from the IRI/CPC, with the probabilistic tug-of-war still leaning in it’s favour looking forward.

figure1

During June, ENSO-neutral continued, although equatorial sea surface temperatures (SSTs) remained above average in the central and east-central Pacific Ocean. The latest weekly Niño index values were near +0.5°C in the Niño-4 and Niño-3.4 regions, and closer to zero in the Niño-3 and Niño-1+2 regions. The upper-ocean heat content anomaly was above average during June (Fig. 3), reflecting above-average sub-surface temperatures across the central and eastern Pacific, reflecting above-average sub-surface temperatures across the central and eastern Pacific. In the atmosphere, tropical convection was suppressed over the west-central tropical Pacific and enhanced over the Maritime Continent. The lower-level and upper-level winds were near average over most of the tropical Pacific, and the Southern Oscillation Index (SOI) and Equatorial SOI were slightly negative to near-zero. Overall, the ocean and atmosphere system remains consistent with ENSO-neutral.

Some models predict the onset of El Niño (3-month average Niño-3.4 index at or greater than 0.5°C) during the Northern Hemisphere summer. However, more than half of the models favor ENSO-neutral through the remainder of 2017. These predictions, along with the near-average atmospheric conditions over the Pacific, lead forecasters to favor ENSO-neutral into the winter (~50 to 55% chance). However, chances for El Niño remain elevated (~35-45%) relative to the long-term average. In summary, ENSO-neutral is favored (~50 to 55% chance) into the Northern Hemisphere winter 2017-18.

Advertisements