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Winter
Outlook
December 2006 - February 2007
by
Glenn Carrin
The
official Winter Outlook from the Climate Prediction
Center places northwest Louisiana, southwest
Arkansas, northeast Texas, and southeast Oklahoma
in a very typical regime. That is, there are
equal chances that this winter will be above,
below, and near normal for both temperature
and precipitation. Here are their graphics:
However,
a WFO Shreveport climate study of the local
impacts from certain Atlantic and Pacific Ocean
sea surface temperature (SST) oscillations provides
another look into the upcoming winter.
Of
the three SST oscillations considered, the tropical
Pacific has begun a warm phase, while the North
Atlantic remains in a decade-long warm regime.
The forecast difficulty comes from the North
Pacific which has been in a generally warm regime
for several years, but with occasional temporary
departures to a cool phase. Such a cool phase
began in August, and will probably last until
November. For our forecast we will assume that
a return to a warm regime in the North Pacific
will occur by the winter.
Thus,
in Shreveport, when all three SST oscillations
are in a warm phase, we climatologically experience
temperatures which are about a degree cooler
than normal, precipitation which is about an
inch and a half below normal for the season,
and a slightly less active severe weather season.
The
Drought of 2005-06 Continues…
|
(Top)
An Iso-analysis of rainfall totals across
the four-state region from January 2006
through September 2006.
(Bottom) A look at how the drought has affected
areas such as the Toledo Bend Reservoir.
The reservoir was some 11 feet below normal
pool stage in early October. Photo courtesy
of Mr. Wiley Butler. |
Moderate
to extreme drought conditions have persisted
across Southeast Oklahoma, Southwest Arkansas,
Northeast Texas, and much of Northwest Louisiana
since late spring of 2005. Although drought
conditions did ease from January to March
of 2006, below normal rainfall has fallen
almost every month since then. As a result,
the ongoing drought has worsened over the
late spring and summer months, with severe
and extreme drought conditions shifting from
Southeast Oklahoma and Southwest Arkansas,
into much of Northern and Northeast Texas,
where only 20 to 25 inches of rain has fallen
this year, through the end of September. This
is some 10 to 15 inches below normal, and
only 30-50% of normal. Drought conditions
ease farther east into Southwest Arkansas
and Northern Louisiana, where 25 to 35 inches
of rain has fallen for the year, but still
some 3 to 12 inches below normal.
The accumulated warmer than normal summer
temperatures experienced area-wide contributed
to the deteriorating drought conditions as
well, as many locations experienced on average
11 to as many as 22 days where afternoon temperatures
topped the century mark. Only random afternoon
showers and thunderstorms occurred during
the summer months, providing some brief relief
to isolated locations. The above normal temperatures
and lack of rainfall through much of this
year have contributed to the continued burns
bans across the region, as well as water conservations
measures in place mainly across communities
of East Texas and Northwest Louisiana. Area
lakes, river, and bayous continue to slowly
recede, with all area reservoirs having fallen
below their normal conservation pool stages,
with the most significant impacts being felt
across the Northeast Texas reservoirs in the
Red, Sabine, Sulphur, and Neches River basins.
Gauge sites along the Sabine River have recorded
record low stages from Gladewater, to Beckville,
and Logansport. Broken Bow Lake, Lake of the
Pines, Caddo Lake, Black Lake, Lake Fork,
Lake Jacksonville, and Sam Rayburn Lake have
all recorded current pool stages some three
to six feet below their normal pool stages,
while Lake Bob Sandlin, Bodcau Lake, Martin
Lake, and Lake Tyler are currently seven to
nine feet below normal pool stage�the exception
being Bodcau Lake, which is nearly twelve
feet below normal.
The drought continues to significantly impact
the area economically and agriculturally.
For a second straight year, hay supplies and
harvests have been short across much of East
Texas, only producing a third of their normal
yield. This has resulted in increased hay
prices, and have required some farmers to
buy hay out of state, or to completely liquidate
their herds due to the increasing expenses
of supplying supplemental feed and acquiring
hay out of state. Smaller herd sizes will
curtail beef supplies, while the lack of adequate
nutrition for cows will mean a smaller calf
crop next year. Many ponds, tanks, and creeks
remain well below normal, if not completely
dry, across several East Texas counties. Some
help is in the offing, however, as the Texas
Department of Agriculture will administer
financial assistance to eligible livestock
producers in 216 drought-stricken counties
throughout the state.
The possibility of a developing El Nino in
the equatorial Pacific will ultimately determine
the precipitation and temperature patterns
on the Four State Region this fall/winter.
Should the El Nino be strong enough, this
would favor above normal wintertime rainfall
and below normal wintertime temperatures from
November through February.
The following table indicates the accumulated
rainfall, their departures, and percentage
of normal since the drought began last May,
2005, with totals ending on September 30th,
2006, a 17 month running total:
Location |
17-Month
Rainfall Total:
May 1, 2005 - Sept. 30, 2006 |
Departure
From Normal |
%
Normal |
Shreveport,
LA |
48.11 |
-23.40 |
67% |
Monroe,
LA |
54.39 |
-18.60 |
75% |
Texarkana,
AR |
42.95 |
-22.80 |
65% |
Lufkin,
TX |
40.34 |
-25.51 |
61% |
Tyler,
TX |
35.72 |
-25.51 |
58% |
Longview,
TX |
39.87 |
-28.36 |
58% |
El
Dorado, AR |
41.68 |
-33.74 |
55% |
DeQueen,
AR |
43.07 |
-33.70 |
56% |
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Volume III, Issue 2
Winter 2006-2007
INSIDE
THIS ISSUE:
2 |
2 |
3 |
3 |
4 |
5 |
5 |
5 |
6 |
7 |
8 |
9 |
9 |
9 |
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