Flood Potential Outlook
Issued by NWS Lake Charles, LA

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HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE LAKE CHARLES LA
1238 PM CST THU MAR 5 2015

...SPRING FLOOD POTENTIAL OUTLOOK FOR SOUTHEAST TEXAS...SOUTHWEST
AND CENTRAL LOUISIANA...

INTRODUCTION...

THIS IS THE 2015 SPRING FLOOD POTENTIAL OUTLOOK ISSUED BY THE
NATIONAL WEATHER SERVICE IN LAKE CHARLES LOUISIANA. THIS ISSUANCE
OUTLINES CURRENT RIVER AND SOIL MOISTURE CONDITIONS AND HIGHLIGHTS
POTENTIAL SITUATIONS THAT COULD INDUCE FLOODING.

ANTECEDENT CONDITIONS...
DURING THE PAST TWO MONTHS...SOUTHEAST TEXAS AND SOUTHWEST AND
CENTRAL LOUISIANA HAVE EXPERIENCED GENERALLY BELOW NORMAL TO TO NEAR
NORMAL PRECIPITATION ACROSS THE AREA...WITH THE DRIEST CONDITIONS
FOUND ACROSS CENTRAL LOUISIANA. THIS CORRESPONDS TO THE WATER YEAR SO FAR
(SINCE OCTOBER 1 2014) WITH RAIN TOTALS RUNNING BETWEEN 50 AND 90
PERCENT OF NORMAL WITH THE EXCEPTION OF A FEW POCKETS IN SOUTHEAST
TEXAS AND SOUTHWEST LOUISIANA WHERE RAIN AMOUNTS HAVE BEEN NEAR
NORMAL.

ACCORDING TO THE US GEOLOGICAL SURVEY (USGS)...CURRENT 28 DAY
AVERAGE STREAMFLOW CONDITIONS ACROSS THE AREA SHOW BELOW NORMAL
CONDITIONS WITH FLOWS AVERAGING 20 PERCENT OF NORMAL. RECENT
RAINFALLS IN THE PAST WEEK HAVE CREATED A SUBSTANTIAL INCREASE IN
SHORT TERM STREAM FLOWS.

THE LATEST DROUGHT MONITOR INDICATES MODERATE DROUGHT CONDITIONS IN
SOUTH CENTRAL LOUISIANA AND ABNORMALLY DRY ELSEWHERE IN LOUISIANA.


RIVER BASIN HYDROLOGIC OUTLOOK...

...NECHES AND SABINE RIVERS AND TRIBUTARIES...

RAINFALL THE PAST TWO MONTHS HAS BEEN NEAR TO SLIGHTLY BELOW NORMAL
ON THE SABINE AND NECHES BASINS. BASED ON EXISTING SOIL
MOISTURE...STREAMFLOW...AND NORMAL SPRING RAINFALL PATTERNS...THE
POTENTIAL FOR SPRING FLOODING IS NEAR NORMAL AT THIS TIME. IT SHOULD
BE REMEMBERED THAT FLOODING IN THE SABINE AND NECHES BASINS RESULTS
FROM HEAVY RAINFALL OVER A SHORT PERIOD OF TIME AND THESE
OCCURRENCES CAN NOT BE PREDICTED WELL IN ADVANCE.


...CALCASIEU...MERMENTAU AND VERMILION RIVERS AND TRIBUTARIES...

DURING THE PAST TWO WEEKS, PRECIPITATION HAS BEEN NEAR NORMAL OVER
THE CALCASIEU AND MERMENTAU BASINS AND SOIL MOISTURE CONTENT IS
NORMAL. SEASONAL FLOODING IS OCCURRING AND FORECAST. OBSERVED DAILY
STREAMFLOWS AS A PERCENT OF MEAN ARE GIVEN BELOW.

                                              3/4
CALCASIEU RIVER              GLENMORA LA     111%
CALCASIEU RIVER                KINDER LA      97%
MERMENTAU RIVER             MERMENTAU LA     193%

BASED ON EXISTING SOIL MOISTURE...STREAMFLOW...AND NORMAL SPRING
RAINFALL PATTERNS...AN AVERAGE FLOOD POTENTIAL IS EXPECTED ACROSS
THE MERMENTAU AND CALCASIEU BASINS.


...LOWER RED RIVER...

STREAMFLOWS ARE NEAR NORMAL FOR THE RED RIVER BASIN DOWNSTREAM OF
FULTON ARKANSAS. DROUGHT CONDITIONS HAVE BEEN ALLEVIATED FROM ABOVE
NORMAL PRECIPITATION OVER THE PAST TWO WEEKS. UPPER RED BASIN AND
OVERALL SOIL MOISTURE CONTENT IS NORMAL TO SLIGHTLY ABOVE NORMAL.
MINOR FLOODING IS OCCURRING AND EXPECTED IN THE UPPER RED RIVER
BASIN.

BASED ON EXISTING SOIL MOISTURE...STREAMFLOWS...AND NORMAL SPRING
RAINFALL PATTERNS...A AVERAGE FLOOD POTENTIAL IS EXPECTED ACROSS THE
LOWER RED RIVER VALLEY.

...ATCHAFALAYA RIVER...
DURING THE EARLY WINTER, MUCH BELOW NORMAL STREAMFLOW CONDITIONS
HAVE OCCURRED OVER THE LOWER OHIO RIVER WHILE NORMAL TO BELOW NORMAL
STREAMFLOW CONDITIONS OCCURRED IN THE MIDDLE MISSISSIPPI RIVER. OVER
THE PAST TWO WEEKS CONDITIONS HAVE IMPROVED WITH ABOVE NORMAL
PRECIPITATION AMOUNTS WHICH HAS LED TO NORMAL STREAMFLOW CONDITIONS
ON THE MIDDLE MISSISSIPPI RIVER.

DURING THE PAST TWO WEEKS, SEASONAL FLOODING HAS OCCURRED OVER THE
SMALLER TRIBUTARIES OF THE MISSISSIPPI RIVER. NO FLOODING HAS
OCCURRED ON THE LOWER OHIO AND MISSISSIPPI RIVERS THIS SEASON.
CURRENTLY MINOR RISES ARE OCCURRING ON THE LOWER MISSISSIPPI RIVER
APPROACHING VICKSBURG.

AS OF MARCH 4...STREAMFLOW ON THE ATCHAFALAYA RIVER NEAR SIMMESPORT
WAS NEAR 77% OF NORMAL.

BASED ON EXISTING SOIL MOISTURE...STREAMFLOW CONDITIONS...AND NORMAL
SPRING RAINFALL PATTERNS...AN AVERAGE FLOOD POTENTIAL IS EXPECTED
ALONG THE ATCHAFALAYA RIVER. THE MAGNITUDE OF FUTURE CRESTS
WILL DEPEND ON THE AMOUNT AND EXTENT OF ANY UPSTREAM ACCUMULATIONS
OF SNOW COVER AND RESULTANT SNOWMELT...COUPLED WITH THE
FREQUENCY...INTENSITY...AND EXTENT OF SPRING RAINS.


METEOROLOGICAL OUTLOOK...
A SERIES OF DISTURBANCES WILL AFFECT THE AREA OVER THE NEXT 7 TO 10
DAYS...BRINGING OCCASIONAL CHANCES FOR RAIN.  CURRENTLY RAINFALL
AMOUNTS ARE EXPECTED TO AVERAGE BETWEEN 1 AND 3 INCHES ACROSS THE
AREA.

CLIMATOLOGICAL OUTLOOK...

THE 8-14 DAY OUTLOOK ISSUED BY THE NWS CLIMATE PREDICTION CENTER
INDICATES HIGHER CHANCES OF ABOVE NORMAL PRECIPITATION FOR SOUTHEAST
TEXAS AND SOUTHWEST AND CENTRAL LOUISIANA. HIGHER CHANCES OF ABOVE
NORMAL TEMPERATURES ARE ALSO EXPECTED FOR THE ENTIRE AREA.

THE 30-DAY OUTLOOK FOR THE MONTH OF MARCH INDICATES GREATER CHANCES
FOR ABOVE NORMAL PRECIPITATION AND BELOW NORMAL TEMPERATURES FOR THE
AREA...WHILE THE 90-DAY OUTLOOK INDICATES HIGHER CHANCES OF BELOW
NORMAL TEMPERATURES AND EQUAL CHANCES OF ABOVE...BELOW OR NORMAL PRECIPITATION.


PLEASE DIRECT QUESTIONS AND COMMENTS CONCERNING THIS OUTLOOK TO...

JONATHAN BRAZZELL
SERVICE HYDROLOGIST
OR
MONTRA LOCKWOOD
FORECASTER
AT 337.477.5285 EXT 1

REFERENCES...
PRECIPITATION ANALYSIS:
HTTP://WATER.WEATHER.GOV/PRECIP/

STREAMFLOW CONDITIONS:
HTTP://WATERDATA.USGS.GOV/NWIS/RT

SOIL MOISTURE CONDITIONS:
HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/SOILMST_MONITORING/US/SOILMST/SOILMST.SHTML

US DROUGHT MONITOR AND OUTLOOK:
HTTP://WWW.DROUGHT.UNL.EDU/DM/MONITOR.HTML
HTTP://WWW.CPC.NOAA.GOV/PRODUCTS/EXPERT_ASSESSMENT/SEASON_DROUGHT.GIF

TX DROUGHT INFORMATION:
HTTP://WWW.TWDB.STATE.TX.US/APPS/DROUGHTINFO/ALLMAPVIEW.ASPX

CLIMATE GRAPHICS:
HTTP://WWW.CPC.NOAA.GOV/
HTTP://WWW.CPC.NOAA.GOV/PRODUCTS/PREDICTIONS/LONG_RANGE/LEAD01/OFF01_TEMP.GIF
HTTP://WWW.CPC.NOAA.GOV/PRODUCTS/PREDICTIONS/LONG_RANGE/LEAD01/OFF01_PRCP.GIF

$$








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