East Coast Set-up for Eventual Tropical Development

Ocean Cools Southwest of California = Cooler (Less Hot) Pattern Change
08/19/2018, 12:24 pm EST
Record Low Rhine & Danube River Levels
08/22/2018, 1:33 pm EST
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Fig. 1:  Satellite view of the North Atlantic basin. Note the high latitude easterly shear off the East Coast.

Discussion: ALL CLEAR across the North Atlantic basin. But! Some interesting developments. Note the easterly shear in the upper atmosphere off the Mid-Atlantic Coast. That’s much farther north than usual. Also note the cloudiness east of the Mid-Atlantic region gathered over very warm ocean water. Nothing organized but this pattern is persisting. This set-up implies eventual development off the East Coast of tropical threats over the very warm waters in that region. In the deep tropics there is upper westerly shear albeit weakening. However, in the higher atmosphere, due to a record-strength easterly quasi-biennial oscillation (-QBO) strong upper easterly shear will likely prevent deep tropics hurricanes. Conversely, -QBO means that the subtropics are actually quite favorable for tropical cyclones. In 2005 when a record 28 tropical cyclones occurred with a strong –QBO almost all of that activity formed/flourished in the subtropics. We’re not expecting an active year BUT the concern here is that tropical systems could form off the East Coast in very warm water and drift east and inland where very wet soils are already located in parts of the Mid-Atlantic region. The already wet soils enhances downed tree (and other structures)/power loss risk.

Fig. 2:  North Atlantic sea surface temperature anomaly analysis identifies super warm waters off New England/Mid-Atlantic.

Fig. 3:  Excessive wet soils in the Mid-Atlantic region.