Flood Potential Outlook
Issued by NWS Columbia, SC

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Winter/Spring Flood Potential Outlook
National Weather Service Columbia SC
154 PM EDT Fri Apr 27 2018


...Spring Flood Potential Outlook...
...Last Spring Flood Outlook Issued For the Season...


...Although the area continues to experience some river flooding,
the potential for river flooding remains near normal for the
Spring across the Midlands and Central Savannah River Area...

This Spring Flood Potential Outlook is for rivers and tributaries
of the Central Savannah River Basin...East-Central Georgia and
Central South Carolina including the following:

Savannah River Basin Downstream of R. B. Russell Reservoir and
upstream from Burtons Ferry...

The Edisto River basin upstream of the Bamberg and Orangeburg
County line in South Carolina...

The Santee River Basin upstream of the Clarendon and Berkeley
County line and downstream on the Saluda and Broad Rivers at the
Greenwood/Saluda...Laurens/Newberry...Union/Fairfield and the
Chester/Fairfield County lines in South Carolina...

The Wateree River System downstream of Great Falls South
Carolina...

The Great Pee Dee River Basin in Chesterfield County in South
Carolina...

           ...Summary of Recent Weather Events...

Over the last 14 days ending April 26 2018...the hydrologic area
received rainfall amounts that ranged from 2 to 5 inches. The
heaviest rain fell across the eastern Midlands and Pee Dee
Regions. This extends from Chesterfield county southward through
Kershaw, Lee, Sumter, Clarendon, Calhoun and Orangeburg counties.
This along and south of the I-20 corridor. This ranges from 125 to
200 percent of normal across the Central Savannah River Area up to
300 to 600 percent of normal across the eastern Midlands and Pee
Dee Regions.

           ...Soul Moisture-Drought Conditions...

Here is a breakdown of the current conditions across the Midlands
and CSRA.

Rainfall over the past 2 weeks has been well above normal across
the Midlands and Central Savannah River Area (CSRA). This has
resulted in a decrease in the areal coverage of drought
conditions. The area of D0, abnormally dry, has been discontinued
across the western Midlands and northern Midlands. Much of the
area covered by D1, moderate drought, has been reduced to D0. This
includes much of the northern CSRA, central Midlands and eastern
Midlands. Much of the area covered by D2, severe drought, has been
reduced to D1. This includes most of the CSRA and southern
Midlands. However, nearly all of Bamberg County and a small area
along the Bamberg and Orangeburg County line still remains in D2
drought. Little to no rainfall along with more seasonal temperatures
are expected over the next 7 days.

Go to www.drought.gov for more details.


           ...River and Stream Flow...

Looking at the 14-day stream flow average compared to historical
streamflows for April 26 2018 show most of the stream basins
across the Midlands and CSRA have been recharged by the recent
heavy rainfall. Stream flow conditions, for the 14-day average,
have greatly improved. Some stream basins continue to show below
normal flows. This includes the Savannah River Basin and the
Edisto River Basin. Conditions have improved to near normal flows
along the Catawba/Wateree River Basin, Santee River Basin, Great
Pee Dee River Basin and the Lynches River Basin. Above normal
flows have returned to the Saluda River Basin and Broad River
Basin. Note, many stream flows across the area are impacted by
reservoir project operations.

Broad River Basin: Above Normal flows
Catawba/Wateree River Basin: Normal flows
Saluda River Basin: Above Normal flows
Santee River Basin: Normal flows
Edisto River Basin: Below Normal flows
Savannah River Basin: Below Normal flows

           ...Reservoir Levels...

Reservoir pool elevations rose over the past 2 weeks across the
Midlands and CSRA. For the first time in quite awhile, all of
the area reservoirs are at or near the Spring target pool/guide
curves. A Note, reservoir pool elevations are dependent on project
operations.

Lake Thurmond (FP 330.0 Feet)...
Apr 11 2018    327.39 Feet
Apr 26 2018    329.59 Feet
Difference Plus  2.20 Feet

Lake Greenwood (FP 440.0 Feet)...
Apr 11 2018    438.93 Feet
Apr 26 2018    439.00 Feet
Difference Plus  0.07 Feet

Lake Murray (FP 360.0 Feet)...
Apr 11 2018    358.11 Feet
Apr 26 2018    358.16 Feet
Difference Plus  0.05 Feet

Lake Marion (FP 76.8 Feet)...
Apr 11 2018     75.21 Feet
Apr 26 2018     75.83 Feet
Difference Plus  0.62 Feet

Lake Wateree (FP 100.00 Feet)...
Apr 11 2018     97.43 Feet
Apr 26 2018     98.45 Feet
Difference Plus  1.02 Feet

Data for this segment was gathered from the United States
Geological Survey...the United States Army Corps of
Engineers...Duke Energy...South Carolina Electric and
Gas...Greenwood County and Santee Cooper.


      ...Precipitation and Temperature Outlooks...

Near Term...A dry cold front will move across the area Saturday
evening. High pressure will build in across the area for Sunday
through much of next week.

Please see the Gridded Forecasts for the chance of rain over the
next 7 days at weather.gov/cae.

The 8- to 14-day outlook for the period May 4 through 10th calls
for equal chances of above, below or near normal temperatures
along with a 40 percent chance of above normal precipitation.

The 30-day outlook for May 2018 indicates a 33 to 40 percent
chance of above normal temperatures along with a 33 to 40 percent
chance of above normal precipitation.

The 3-month outlook for May, June and July calls for a 40 percent
chance of above normal temperatures along with a equal chances of
above, below and normal precipitation.

Go to the Climate Prediction Center webpage at
www.cpc.ncep.noaa.gov for more details and the latest outlooks.

                   ...Summary/Outlook...

Recent rainfall has reduced much of the rainfall deficits and
improved stream flows across the Midlands and Central Savannah
River Area. This will be the last issuance of the Winter/Spring
Flood Outlook for the Midlands and Central Savannah River Area.

Historically...the River Flood Season begins in early to mid
January with the number of river flood events increasing through
late Winter into early Spring. The peak occurs in early to mid
March then begins to end in late April for the region. This trend
has been the case for this year, as the occurrence of river
flooding increased during the month of April. However, the trend
did get off to a slightly slower start this year.

The medium- to long-range precipitation guidance indicates that
precipitation may be close to normal for the region as Spring
comes to and end and Summer begins.

The next schedule Winter/Spring Flood Outlook is scheduled for
January 2019.


                ...Questions and Comments...

If you have any questions or comments about this outlook please
contact...

The National Weather Service
2909 Aviation Way
West Columbia SC 29170
Phone: 803-822-8135
Internet Address: caewx@noaa.gov
Senior Service Hydrologist:
Leonard.Vaughan@noaa.gov


$$



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