Flood Potential Outlook
Issued by NWS Greer, SC
FGUS72 KGSP 180249
SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1030 PM EST THU MAR 17 2016
...The latest Spring Flood Potential Outlook downgrades the
risk for flooding region-wide as soils continue to dry and
streamflows continue to decrease during a long-term period
of below-normal precipitation...
...The latest Spring Flood Potential Outlook for the
Western Carolinas and Extreme Northeast Georgia calls for a
BELOW NORMAL to SLIGHTLY ABOVE NORMAL risk for small-stream
flooding and a BELOW NORMAL to NORMAL risk for mainstem river
flooding across the region through early spring 2016...
The mainstem river flood season typically begins in late December.
The quantity...frequency...magnitude...and significance of river
flood events often increases through late winter with a peak in
early to mid-March. The river flood season typically ends by late
April for the region. While this flood season began early...in
October...and stayed active through early January...flood
occurrences have decreased significantly through mid-March. Above-
normal precipitation observed during past El-Nino winters has not
materialized in 2016. The below-normal rainfall across the entire
region is allowing streamflows to decrease from much-above normal
peaks and is reducing the overall risk for above-normal flooding
through the middle of spring.
14-DAY OBSERVED PRECIPITATION and FLOODING...
Region Observed % of Mainstem Small Stream
Precip Normal Flooding Flooding
NC Piedmont 0.01-1.10 | 1- 80 | None | None
NC Foothills 0.10-0.60 | 5- 35 | None | None
NC Nrn Mnts 0.25-0.90 | 10- 60 | NA | None
NC Cntl Mnts 0.10-1.50 | 10- 50 | None | None
NC Srn Mnts 0.40-1.50 | 25- 50 | None | None
SC Mnts 1.00-2.00 | 40- 80 | NA | None
SC Foothills 0.50-2.50 | 25-125 | None | None
SC Piedmont 0.40-2.50 | 20-125 | None | None
GA NE Mnts/ 0.50-1.75 | 15- 75 | None | None
GA Piedmont 0.25-1.25 | 10- 60 | None | None
14-DAY AVERAGE STREAMFLOW STATISTICS BY REGION
Region % of % of %ile Classification
(3/4) (3/17) (3/17) (3/17)
NC Piedmont 80-130 | 15-100 | 5-50 | Below Normal
NC Foothills 170-190 | 70-110 | 40-80 | Normal
NC Nrn Mnts 175-200 | 75- 85 | 35-45 | Slightly Below Normal
NC Cntl Mnts 160-225 | 80-100 | 40-60 | Normal
NC Srn Mnts 160-200 | 90-125 | 45-75 | Normal
SC Mnts NA | NA | NA | NA
SC Foothills 65-120 | 75-100 | 35-65 | Normal
SC Piedmont 120-150 | 40- 80 | 30-40 | Slightly Below Normal
GA NE Mnts/ 150-175 | 85-125 | 45-80 | Slightly Above Normal
GA Piedmont 100-130 | 75-110 | 45-70 | Normal
14-DAY AVERAGE STREAMFLOW STATISTICS BY PRIMARY RIVER SYSTEM/BASIN
Stream/Basin % of % of %ile Classification
(3/4) (3/17) (3/17)
Broad (GA) 100-130 | 75-110 | 45-70 | Normal
Broad (NC/SC) 120-160 | 75-100 | 30-60 | Slight Below Nrml
Catawba 120-150 | 15-100 | 5-60 | Below Normal
Enoree/Tyger 100-160 | 60-125 | 30-80 | Normal
French Broad 160-210 | 70-110 | 40-70 | Normal
Little Tennessee- 160-225 | 80-140 | 40-80 | Slight Abv Normal
Piegon 180-225 | 75- 90 | 40-50 | Normal
Rocky (NC) 90-125 | 20- 75 | 5-40 | Below Normal
Saluda 120-150 | 60-110 | 30-70 | Normal
Tallulah-Chattooga 140-175 | 100-125 | 60-80 | Slight Abv Normal
Toxaway-Keowee- 100-125 | 75-120 | 45-60 | Normal
Most reservoirs across the region are at or slighly above their
target pools for this time of year.
SNOW DEPTH and FORECAST...
Region Snow Snow Water 7-Day Snow
Depth Equivalent Forecast
(in) (in) (in)
NC Piedmont None | None | None
NC Foothills None | None | None
NC Nrn Mnts None | None | 0-2
NC Cntl Mnts None | None | 0-1
NC Srn Mnts None | None | 0-0.5
SC Mnts None | None | None
SC Foothills None | None | None
SC Piedmont None | None | None
GA NE Mnts/ None | None | None
GA Piedmont None | None | None
1-7 DAY FUTURE PRECIPITATION FORECAST and FLOOD POTENTIAL...
Region 7-Day % of Mainstem Small Stream
Precip Normal Flood Ptntl Flood Ptntl
NC Piedmont 0.25-0.50 | 20-66 | Zero | Zero
NC Foothills 0.25-0.50 | 20-60 | Zero | Zero
NC Nrn Mnts 0.25-0.75 | 20-100 | NA | Zero
NC Cntl Mnts 0.25-0.75 | 20-115 | Zero | Zero
NC Srn Mnts 0.25-0.60 | 15-66 | Zero | Zero
SC Mnts 0.25-0.50 | 15-40 | NA | Zero
SC Foothills 0.25-0.50 | 20-40 | Zero | Zero
SC Piedmont 0.25-0.50 | 20-66 | Zero | Zero
GA NE Mnts/ 0.25-0.50 | 15-40 | Zero | Zero
GA Piedmont 0.25-0.50 | 20-40 | Zero | Zero
8-90 DAY PRECIPITATION OUTLOOKS...
Region 8-14 Day 15-30 Day 30-90 Day
Precip Precip Precip
Outlook Outlook Outlook
NC Piedmont Above Normal | Slight Abv Nrml | Slight Abv Nrml
NC Foothills Above Normal | Slight Abv Nrml | Slight Abv Nrml
NC Nrn Mnts Above Normal | Slight Abv Nrml | Slight Abv Nrml
NC Cntl Mnts Above Normal | Slight Abv Nrml | Slight Abv Nrml
NC Srn Mnts Above Normal | Slight Abv Nrml | Slight Abv Nrml
SC Mnts Above Normal | Slight Abv Nrml | Slight Abv Nrml
SC Foothills Above Normal | Slight Abv Nrml | Slight Abv Nrml
SC Piedmont Above Normal | Slight Abv Nrml | Slight Abv Nrml
GA NE Mnts/ Above Normal | Slight Abv Nrml | Slight Abv Nrml
GA Piedmont Above Normal | Slight Abv Nrml | Slight Abv Nrml
Note that Equal-Chances means there are equal chances for
above-normal...normal...and below-normal precipitation during
the given period. In other words, there is no clear signal for
precipitation during the given period.
LONG-TERM FLOOD OUTLOOK...
Therefore...given current antecedent conditions and long-range
precipitation guidance...the long-term flood outlook through the
end of April 2016 is as follows...
Region Runoff Mainstem Small
Potential Rivers Streams
NC Piedmont Below Normal | Below Normal | Below Normal
NC Foothills Normal | Slight Blw Nrml | Normal
NC Nrn Mnts Slight Blw Nrml | NA | Slight Blw Nrml
NC Cntl Mnts Slight Abv Nrml | Normal | Slight Abv Nrml
NC Srn Mnts Slight Abv Nrml | Normal | Slight Abv Nrml
SC Mnts NA | NA | Normal
SC Foothills Normal | Slight Blw Nrml | Normal
SC Piedmont Slight Blw Nrml | Below Normal | Slight Blw Nrml
GA NE Mnts/ Slight Abv Nrml | Normal | Slight Abv Nrml
GA Piedmont Normal | Slight Blw Nrml | Normal
The precipitation analysis is derived from quality-controlled
gridded precipitation estimates produced at the Lower Mississippi
River Forecast Center /LMRFC/ and the Southeast River Forecast
The 1-7 day future precipitation is derived from guidance produced
at the Weather Prediction Center /WPC/.
The long-term precipitation outlooks are derived from guidance
produced at the Climate Prediction Center /CPC/.
Streamflow imformation is courtesy of the United States Geological
Reservoir information is courtesy of Duke Energy...Georgia Power...
and the US Army Corps of Engineers /USACE/.
The general outlook is produced in collaboration with the LMRFC and
NEXT ISSUANCE DATE...
The next flood outlook will be issued by Friday...April 1st...2016.
For the latest status of streams and mainstem rivers across the region
QUESTIONS or COMMENTS...
This product has undergone several revisions and enhancements during the
most recent flood outlook period. Additional enhancements are planned
for future flood outlooks. Your feedback and recommendations are
encouraged in order to ensure this product meets user needs. Please
direct feedback...recommendations...questions...and comments to:
National Weather Service
Weather Forecast Office - Greenville-Spartanburg
1549 GSP Drive
Greer SC 29651