Declining Hw in northwestern ICH

Declining Hw feasibility in the northwestern group of ICH units; ICHmc1, ICHmc2, and also CWHws1 (just south of ICHmc2).
Low elevation units.
o ICHmc2 – shift from E1 to E2, future BGCs are ICH and CWH units (ICHmw3, mw2, mc2, dw4, dw3, CWHws1, ds2, ds1).
o ICHmc1 – very similar results as ICHmc2, see example below.
o CWHws1 – 50% decline to E2, 50% maintained at E1. Shifts more towards E2 through time. BGC futures are CWH (ws1, wm, vm1, ms2, ds2, ds1, xm1).

Climate drivers – does this area become too dry for Hw? East side of Coast Mountains.
CMIP6 model ensemble predicts a slight increase in precip in the winter, spring and autumn. Projections for summer are split, some predict increasing precip, others predict a decrease in precip.

Hw on C4 sites 2041-2061. Historical feasibility is E1. Shift to E2.
ICHmc1/01. Feasibility declines from E1 to E2.
ICH units from the southeast are projected. Hw is maintained at low – mid elevation on the coast. Hw feasibility is declining as you move across the coast-interior transition. What are the climate drivers? Becoming drier on the east side of the Coast Mountains?

Start with the Hw feasibility examples for ICHmc2, ICHmc1, and CWHws1 in this issue, then compare them with the listed CMIP6 winter, spring, autumn, and summer precipitation projections. The issue is complete when the climate drivers behind the east-of-Coast-Mountains decline, including the transition from E1 to E2, are identified and documented.

Written by the indexing model from the issue text.