|Colorado (and Interior
Executive summary (20 September 2002)
Complete report can be found here: http://www.cdc.noaa.gov/~kew/SWcasts/
Questions should be addressed to:
Klaus Wolter (email@example.com
(303) 497 -6340.
- El Niño made a recovery last month, and is now
entering the time of year when changes from month to month
should be less pronounced than previously. Such calmer behavior
also translates into a better consensus among different
ENSO forecasts, now indicating moderate El Niño conditions
for the upcoming winter.
- Historically, even modest El Niño conditions have
been associated with wetter than average conditions for
November in Colorado and several adjacent states, while
September and October show almost no tilt in the odds for
wet or dry conditions.
- The new experimental forecast for October through December
precipitation shows a modest shift in the odds towards wetter-than-average
conditions in northeastern Colorado, compared to continued
uncertainty over the mountains and western Colorado. Further
west and south, there remains an unusual amount of uncertainty
even for Arizona, where El Niño should be good for
a wet fall. However, as this forecast illustrates, there
are many other influences on our climate than just El Niño,
and so far this fall they appear to be more in conflict
with each other than in other years. Looking beyond the
next three months, the outlook for early next year is guardedly
optimistic, with substantial increases in the odds for wet
weather over most of Arizona, much of New Mexico and eastern
Colorado. Unfortunately, the outlook for the north-central
mountains of Colorado remains as uncertain for late winter
as it is for the fall right now.
- Wet weather returned to Colorado during the last few weeks,
with many locales already exceeding their normal monthly
precipitation for September. For much of the state, this
could mean the first wet month since August 2001, wrapping
up an extraordinary year of continuous drought conditions.
Whether this is truly the beginning of the end of the Colorado
Drought of 2002, or just temporary relief, remains to be
seen. With the recent rains soaking the parched ground just
before the end of the growing season, soil moisture is at
least partially restored, and fire danger has been much
reduced from its extreme values through much of the summer.
Snow-capped mountains earlier this week remind us that the
ski season is not far behind, and may even be off to a better-than-average
start, if historic El Niño relationships come through
for much of the state this November.
- Bottomline: The extraordinary Colorado drought of 2002
may have reached its peak last month, along with one last
major peak in wildfire activity levels. Although the outlook
for the remainder of this year is not overly wet, the rains
of September may have broken the vicious cycle of low soil
moisture and fire-caused hazy skies that tended to perpetuate
our drought through the summer. With a slate thus wiped
clear, and a strengthened El Niño in place, we should
have a better chance of realizing the El Niño-related
potential of near-normal or even wet months ahead of us.
Unfortunately, a near-normal or even slightly wet snow season
won't be sufficient to refill our reservoirs. Although a
repeat of last year's dry fall, winter, and spring is not
likely, it would exacerbate our drought conditions so much
that we need to consider what such a scenario would entail.
Future updates of this forecast page should reduce the current
uncertainty in this outlook.
--Prepared by: Klaus
(303) 497 -6340.
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