After a cold March and even colder April, there is confliction between the modelling and my thinking as we go forward.
I believe April 2018 was 3rd coldest for the US since the beginning of the satellite era. 1983 remains coldest because it was colder in the Southwest compared to this year.
Credit: Michael Ventrice
Confliction between man and model
The spring thus far has been largely driven by a highly amplified MJO (Maddan Julian Oscillation) pulse which has kept things cool overall but as it continues to progress through the phases, we’ve seen surges of heat including the developing one now. The models can struggle to see the influence of the MJO within the mid latitudes and can be slow to the party.
The MJO is currently in phases 6 which is correlating well with the building heat east of the Rockies currently but it doesn’t stop there and we swing into cooler phase 7.
GFS shows a warm upcoming 5 days and less warm following 5 days but is it cool enough or does the MJO get beaten by the warmer outlook?
GFS 2m temp anomaly.
Day 1-5
Credit: Tropical Tidbits
Day 6-10
Credit: Tropical Tidbits
The models keep it warm but the MJO is projected to swing into phases 1,2 which are cool.
CFSv2 week 2,3,4.
Credit: Tropical Tidbits
Credit: Tropical Tidbits
Credit: Tropical Tidbits
The point in talking about May and the MJO vs modelling is that the CFSv2 doesn’t look correct for May and indeed the summer.
The La Nina is coming to an end and we may be talking El Nino once again later. Exactly when remains to be seen with some models indicating a weak El Nino by mid to late summer and others later into the fall.
Here’s the current global SST anomaly.
Credit: Tropical Tidbits
Probably the most noteworthy aspect to the above is the contrast between very warm off New England and very cool around Cape Verde. Also note the ribbon of cool running up the East Coast.
Drought breeds heat
With an expanding and intensifying drought from SE California up to Utah and across to Oklahoma and north Texas, one has to wonder if the core of summer heat finds it’s way here. Afterall drought breeds heat and intense heat at that.
A cool Caribbean and deep tropics suggests a potentially slow start to the 2018 hurricane season overall but the central Gulf of Mexico and Western Atlantic off the East Coast is warmer than normal so in close development is possible.
Credit: Tropical Tidbits
A warm Gulf and dry Plains could also aid in an early Southwest and Plains heat wave.
I don’t agree with the below CFSv2 which suggests cooler and wetter than normal for the southern/central Plains. This makes even less sense given the El Nino (if there is one) which isn’t expected to develop until late summer into fall. If an El Nino happened to be developing now, well I could believe the CFSv2 a little more.
CFSv2 June-August
2m temp anomaly
Credit: Tropical Tidbits
Precipitation anomaly
Credit: Tropical Tidbits
So, heat is likely to be the rule from late May on. The only area where I can see cool is the Great Lakes and Ohio Valley, possibly the Northeast. Hottest over the Southern/central Plains extending west towards the Southwest desert and up into the Great Basin.
Expect warmer than for much of the Lower 48 except the Northern Tier, especially the Great Lakes.
FEATURED IMAGE CREDIT: Parker The Snow Dog @officialsnowdog
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