Bloomberg News

U.S. Drought Monitor Report for the Week Ending March 19 (Text)

March 22, 2013

Following is the text of the weekly U.S. Drought Monitor as released by the National Drought Mitigation Center in Lincoln, Nebraska:

Weather Summary: Over the course of the past week, the upper-air
flow pattern featured a trough over the eastern contiguous U.S.
and a ridge over the western U.S., followed by flattened east-
west oriented flow, and ending with a developing trough over the
Nation’s midsection. Temperatures averaged several degrees below
normal for the week across most of the Northeast and Florida,
generally 4 to 8 degrees below normal across the Midwest, and
near 15 degrees below normal in eastern North Dakota. Above
normal temperatures prevailed from the southern Great Plains and
Rockies westward to near the Pacific Coast. The largest positive
departures were observed from central Nevada southeastward to
western New Mexico, on the order of 10 to 14 degrees above
normal. Several storm systems moved across the country during
the period. Heavy precipitation (2 inches or more) fell across
the northern Cascades and Olympic Peninsula of Washington, parts
of the northern Rockies, southern Missouri and southern
Illinois, the Ohio Valley, eastern Pennsylvania, and northern
New Jersey. Light precipitation (less than 0.5-inch) was
observed over California, the Southwest, the interior Pacific
Northwest, most of the Great Plains, Louisiana, parts of the
Corn Belt and Great Lakes, and much of Florida. Most other areas
of the contiguous U.S. reported moderate precipitation (between
0.5 and 2 inches) during the past 7 days.

The Northeast and Mid-Atlantic: Widespread light to moderate
precipitation (under 2 inches) amounts were noted over the
region during the past 7-days.  Eastern Pennsylvania and parts
of northern New Jersey reported heavy precipitation (2-3
inches). Weekly temperatures averaged 2-4 degrees below average
for most of this region, limiting evapotranspiration. With
green-up still several weeks away for areas of higher terrain,
it was decided not to modify the regional drought depiction this
week.

The Southeast: Moderate rains (0.5 - 2 inches) fell across the
Tennessee Valley, Georgia, much of the Carolinas, southeastern
and far northern Alabama, and in very isolated locations across
Florida.  A 1-category improvement was made across extreme
southwestern-, west-central-, and extreme east-central Georgia
due to the recent rainfall, and Percent of Normal Precipitation
(PNP) values ranging from 110-150 percent of normal over the
past 3 months (Advanced Hydrologic Prediction System, AHPS). In
contrast, there was expansion of abnormal dryness (D0) over
southeastern North Carolina and extreme southern Alabama, based
on increasing rainfall deficits and fairly low stream flows.

For the Florida peninsula, rainfall departures (Departure from
Normal Precipitation - DNPs from AHPS) for the past 90-days
generally ranged from 4-6 inches (locally greater). The area of
moderate drought (D1) in southern Florida was expanded northward
to include eastern portions of both Miami-Dade and Broward
counties.

The Midwest: Light precipitation (less than 1 inch) was noted
over much of this region. A 1-category improvement (from D1 to
D0) was made over northern Illinois to be consistent with
surrounding areas that had approximately the same weather and
soil conditions. In southern Wisconsin, a 1-category upgrade was
made, warranted by DNPs (from 14-days to 180-days) in
significant surplus, rivers running high with some minor
flooding reported, and a wet, snowy winter overall.  The
remaining areas of the Midwest were left unchanged in the
drought depiction, due to the continuing presence of frozen
ground. Davenport, IA reported a frozen soil depth of 5 inches,
with very slow thawing occurring.

Lower Mississippi Valley/Delta region: Significant precipitation
deficits (AHPS PNP values of 25-75 percent of normal rainfall
during the past 2 months) justified an eastward expansion of D0
conditions along and near the border between Arkansas and
Louisiana. Stream flows in this region are down in the lowest 10
percent of the historical distribution. In addition, a one-
category degradation was also made to extreme southwestern
counties in Arkansas.

The Great Plains: In Texas, little if any precipitation during
the past week resulted in lots of small-scale adjustments to the
drought depiction. Six-month DNPs are on the order of 8-16
inches in much of eastern Texas. These deficits, and the fact
that reservoirs in most of this area recharged during 2012,
resulted in a new, short-term impact area designation for this
region. In far northwestern Oklahoma, the two separate D2 areas
were combined into one, and expanded slightly to the southeast.
In the far western Panhandle region, Cimarron County in
particular is experiencing widespread winter wheat and native
grass loss. There were some reports of similar, if not worse,
conditions occurring across the Colorado border in Baca County.

The Rockies: Many areas received light precipitation (if any)
during this past week. Moderate to heavy precipitation (greater
than 0.5-inch) was widespread across the northern Rockies, but
unfortunately most of this precipitation did not fall on areas
farther south that needed it. Moderate precipitation (0.5 - 1
inch) was reported over the Colorado Front Range, but not enough
to warrant any alterations to this week’s Drought Monitor
depiction.

The West: Little if any precipitation fell over the Southwest
and the interior Pacific Northwest.  The areas that received
significant precipitation (liquid equivalent) included the
coastal ranges and Cascades of Washington and Oregon, but
unfortunately the rain and mountain snow missed the drought
areas farther east and south. As a result, abnormal dryness (D0)
was expanded across north-central and extreme southwestern
portions of Oregon, and introduced to the far northern counties
of California. In addition, a one-category degradation (from D0
to D1) was rendered to the drought depiction in east-central
California, notably the Yosemite National Park counties of
Tuolumne, Mariposa and Madera. As of March 20th, the basin-wide
Snow Water Content (SWC) from SNOTEL locations across the
Sierras was measured at 50 to 75 percent of average. In
California, 154 intrastate reservoirs are collectively holding a
near-average volume of water for this time of year, though the
runoff situation appears to be fairly pessimistic for the second
year in a row. Snow melt in March is a problem for the
reservoirs which are at the top of their conservation pools, as
they would have to pass any snowmelt runoff since the flood
control curves wait for April 1st before easing. Those
reservoirs with room in the conservation pool can catch the
snowmelt runoff.

Hawaii, Alaska, and Puerto Rico: In Hawaii, some windward
locations reported anywhere from 0.5-inch to as much as 3-4
inches of rain this past week, while little if any rain fell
over the leeward areas. In Alaska, the interior reported little
if any precipitation as well, though anywhere from 0.5-inch to
as much as 3-4 inches of precipitation was recorded this past
week across the Panhandle area. No changes were made to the
depiction in both Hawaii and Alaska.

Mainly light rains fell across Puerto Rico during the past week.
Rainfall deficits of 6-8 inches have accumulated over the past 3
to 6 months across the island, with the southern and western
coasts reporting the worst conditions. Daily grass fires have
been reported over parts of the southern slopes. The area of
abnormal dryness (D0) was expanded southward to include the
southern slopes.

Looking Ahead:  During the next 5 days (March 21-25, 2013), a
corridor of 1.5 - 2.7 inches of rain is expected from northern
Arkansas southeastward into central and southern Georgia, which
will be beneficial for areas experiencing ongoing drought. Up to
1.5 inches of precipitation is anticipated over the Rockies,
including the High Plains of eastern Colorado. In the West, 0.5
- 2.5 inches is forecast to accumulate over the coastal ranges,
Cascades, and Sierras, with little precipitation for the
interior West.

To contact the reporter on this story: Alex Tanzi in Washington at atanzi@bloomberg.net

To contact the editor responsible for this story: Marco Babic at mbabic@bloomberg.net


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