Final.HCI.Report.HDR

• Title: Hydro-Climate Index Study
• Prepared For: CWCB & Colorado River WCD
• Prepared By: HDR Engineering Inc.
• Date: 12/28/2007
• County: Statewide
• State: CO
• Country: USA
• Weather Modification - Doc Type: Scientific Study

Yampa:
Most HCI variable are weak and non - usable with only (at best) some minor
correlation to the PDO however, this relationship may not be of use for multi -year
analysis.
Table 10. Summary of Dec. -Mar. Multi (2 -year) Precipitation/HCI Relationships for the
Colorado /Gunnison/Yampa -White basins (dark `X' indicates a relatively strong relationship and
light 'X' indicates a relatively weak relationship).
April to June Precipitation:
Upper Colorado (River above Kremmling):
The leading modes of the NAO have minor connections but, are unfortunately the
best precipitation depiction possible. Minor connection with ENSO exists however, a
look at the actual connection do not appears to be useful unless the ENSO value
(preferably the SOI) is strongly shifted one way or the other.
Middle Colorado (River from Kremmling to Glenwood Springs):
The leading modes of the NAO have minor connections but, are unfortunately the
best precipitation depiction possible. Minor connection with ENSO exists however, a
look at the actual connection do not appears to be useful unless the ENSO value
(preferably the SOI) is strongly shifted one way or the other.
Eagle:
There is some non - random connection with ENSO (preferably the SOI) with El
Nino years leaning towards more precipitation and vice -versa for the 2 -year spring
average.
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PDO
MEI
SOI
Nino 3.4
NAO
AMO
Upper Colo.
X
Middle Colo.
X
Eagle
X
Roaring Fork
X
X
X
Gunnison
X
X
Uncompaghre
White
X
Yampa
X
April to June Precipitation:
Upper Colorado (River above Kremmling):
The leading modes of the NAO have minor connections but, are unfortunately the
best precipitation depiction possible. Minor connection with ENSO exists however, a
look at the actual connection do not appears to be useful unless the ENSO value
(preferably the SOI) is strongly shifted one way or the other.
Middle Colorado (River from Kremmling to Glenwood Springs):
The leading modes of the NAO have minor connections but, are unfortunately the
best precipitation depiction possible. Minor connection with ENSO exists however, a
look at the actual connection do not appears to be useful unless the ENSO value
(preferably the SOI) is strongly shifted one way or the other.
Eagle:
There is some non - random connection with ENSO (preferably the SOI) with El
Nino years leaning towards more precipitation and vice -versa for the 2 -year spring
average.
36