Flood Potential Outlook
Issued by NWS Lake Charles, LA

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HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE LAKE CHARLES LA
328 PM CST THU MAR 6 2014

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

INTRODUCTION...

THIS IS THE 2014 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 TO NEAR NORMAL
PRECIPITATION. THIS CORRESPONDS TO THE WATER YEAR SO FAR (SINCE
OCTOBER 1 2013) WITH RAIN TOTALS RUNNING BETWEEN 50 AND 90 PERCENT
OF NORMAL WITH THE EXCEPTION OF A FEW POCKETS IN SOUTHEAST TEXAS
WHERE RAIN AMOUNTS HAVE BEEN NEAR NORMAL. COLDER TEMPERATURES HAVE
ALLOWED SOME OF THE WINTER EVENTS TO BE IN THE FORM OF FROZEN
PRECIPITATION...INCLUDING ONE IN EARLY MARCH THAT PRODUCED LIGHT
AMOUNTS OF FREEZING RAIN AND SLEET.

ACCORDING TO THE US GEOLOGICAL SURVEY (USGS)...CURRENT 28 DAY
AVERAGE STREAMFLOW CONDITIONS ACROSS THE NECHES AND SABINE BASINS IN
SOUTHEAST TEXAS SHOW BELOW NORMAL CONDITIONS...WHILE 28 DAY AVERAGE
STREAMFLOWS ACROSS SOUTHWEST AND CENTRAL LOUISIANA (OUTSIDE OF THE
SABINE BASIN) ARE NEAR NORMAL.

THE LATEST DROUGHT MONITOR INDICATES THAT NO AREAS ARE CURRENTLY IN
DROUGHT...HOWEVER PORTIONS OF INTERIOR SOUTHEAST TEXAS AND SOUTH
CENTRAL LOUISIANA ARE NOTED AS BEING ABNORMALLY DRY.

ALTHOUGH PRECIPITATION HAS BEEN SLIGHTLY BELOW NORMAL, SOIL MOISTURE
CONDITIONS CONTINUE TO BE NEAR SEASONAL LEVELS. SNOW MELT AND COLDER
GROUND TEMPERATURES HAVE ALLOWED MANY OF THE PRECIPITATION EVENTS TO
GENERATE MORE RUNOFF THAN IN PAST YEARS.


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. SEASONAL FLOODING HAS OCCURRED
ALONG THE LOWER SABINE BASIN WITH ELEVATED FLOWS ON THE LOWER NECHES
AND ITS TRIBUTARIES DUE TO COLDER TEMPERATURES PRODUCING HIGHER
RUNOFF. DRIER CONDITIONS HAVE ALLOWED STREAMFLOWS TO RECEDE TO BELOW
NORMAL FOR THIS TIME OF YEAR. RESERVOIRS ON THE SABINE AND NECHES
BASINS ARE CURRENTLY NEAR OR JUST BELOW CONSERVATION POOL LEVELS.
SOIL MOISTURE CONTENT IS NORMAL AND NO FLOODING IS OCCURRING OR
EXPECTED DURING THE NEXT SEVERAL DAYS.

BASED ON EXISTING SOIL MOISTURE...STREAMFLOW...AND NORMAL SPRING
RAINFALL PATTERNS...THE POTENTIAL FOR SPRING FLOODING IS NORMAL TO
SLIGHTLY BELOW 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 MONTHS, PRECIPITATION HAS BEEN BELOW NORMAL OVER
THE CALCASIEU AND MERMENTAU BASINS BUT SEASONAL FLOODING HAS
OCCURRED DUE TO COLDER TEMPERATURES PRODUCING HIGHER RUNOFF. DRIER
CONDITIONS HAVE ALLOWED STREAMFLOW TO RECEDE TO BELOW NORMAL
CONDITIONS. SOIL MOISTURE CONTENT IS NORMAL AND NO FLOODING IS
OCCURRING OR EXPECTED DURING THE NEXT SEVERAL DAYS. OBSERVED DAILY
STREAMFLOWS AS A PERCENT OF MEAN ARE GIVEN BELOW.

                                              3/5
CALCASIEU RIVER              GLENMORA LA      36%
CALCASIEU RIVER                KINDER LA      62%
MERMENTAU RIVER             MERMENTAU LA      79%

IN ADDITION...THE OBSERVED DAILY STREAMFLOW FOR THE VERMILION RIVER
AT LAFAYETTE SURREY STREET AS OF MARCH 5 IS SLIGHTLY ABOVE ITS
HISTORICAL MEAN.

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 BELOW NORMAL FOR THE RED RIVER BASIN DOWNSTREAM OF
FULTON ARKANSAS. DROUGHT CONDITIONS CONTINUE OVER THE UPPER RED
BASIN WITH ABNORMALLY DRY CONDITIONS OVER THE BASIN DOWNSTREAM OF
FULTON ARKANSAS.  HOWEVER OVERALL SOIL MOISTURE CONTENT IS NEAR
NORMAL. NO FLOODING IS OCCURRING OR EXPECTED IN THE LOWER RED RIVER
BASIN.

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

...ATCHAFALAYA RIVER...
SNOWFALL HAS OCCURRED ACROSS THE MIDDLE AND UPPER MISSISSIPPI
VALLEYS THE PAST SEVERAL WEEKS...WITH THE MOST SIGNIFICANT SNOW
DEPTHS ACROSS THE UPPER PORTIONS OF THE VALLEY. HOWEVER...SNOW MELT
FROM THIS SNOW IS NOT EXPECTED TO IMPACT THE FLOOD POTENTIAL OVER
THE LOWER MISSISSIPPI VALLEY...INCLUDING THE ATCHAFALAYA BASIN.

ALTHOUGH A FEW OF THE SMALLER TRIBUTARIES OF THE MISSISSIPPI RIVER
HAVE EXPERIENCED SEASONAL FLOODING THIS WINTER...NO FLOODING HAS
OCCURRED ON THE LOWER OHIO AND MISSISSIPPI RIVERS. WARMER
TEMPERATURES LAST WEEK MELTED MUCH OF THE SNOW IN THE MID AND UPPER
OHIO VALLEY AND WELL BELOW FLOOD STAGE CRESTS ASSOCIATED WITH
SNOWMELT AND RAIN ARE APPROACHING MEMPHIS, TN.

SOIL MOISTURE CONDITIONS ARE GENERALLY NORMAL OVER THE ATCHAFALAYA
RIVER VALLEY. AS OF MARCH 5...STREAMFLOW ON THE ATCHAFALAYA RIVER
NEAR SIMMESPORT WAS NEAR 102% OF NORMAL.

BASED ON EXISTING SOIL MOISTURE...STREAMFLOW CONDITIONS...AND NORMAL
SPRING RAINFALL PATTERNS...AN AVERAGE FLOOD POTENTIAL IS EXPECTED
ALONG THE LOWER MISSISSIPPI AND ATCHAFALAYA RIVERS. 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.  HOWEVER...RAIN SHOULD
REMAIN LIGHT WITH AMOUNTS EXPECTED TO REMAIN LESS THAN ONE INCH.

CLIMATOLOGICAL OUTLOOK...

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

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

DROUGHT OUTLOOKS SHOW A GENERAL IMPROVEMENT EXPECTED IN THE
ABNORMALLY DRY CONDITIONS THROUGH EARLY SPRING...ALTHOUGH THE
SEASONAL OUTLOOK SHOWS DROUGHT CONDITIONS POSSIBLY RETURNING TO
COASTAL SOUTHEAST TEXAS AND SOUTHWEST LOUISIANA BY MAY.


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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