New Orleans NWS on the drought, La Nina, and analog seasons

[BayouVenteux]

Our local NWS office issued a special statement this morning regarding the worsening drought that's affected SE Louisiana and much of the Gulf Coast this winter and now, spring. FWIW, some interesting observations were made with regard to La Nina and the upcoming hurricane season:

WWUS84 KLIX 041402
SPSLIX

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
800 AM CDT TUE APR 4 2006

LAZ034>040-046>050-056>070-MSZ068>071-077-080>082-051300-
AMITE MS-ASCENSION LA-ASSUMPTION LA-EAST BATON ROUGE LA-
EAST FELICIANA LA-HANCOCK MS-HARRISON MS-IBERVILLE LA-JACKSON MS-LIVINGSTON LA-LOWER JEFFERSON LA-LOWER LAFOURCHE LA-LOWER PLAQUEMINES LA-LOWER ST. BERNARD LA-LOWER TERREBONNE LA-ORLEANS LA-PEARL RIVER MS-PIKE MS-POINTE COUPEE LA-ST. CHARLES LA-ST. HELENA LA-ST. JAMES LA-ST. JOHN THE BAPTIST LA-ST. TAMMANY LA-TANGIPAHOA LA-UPPER JEFFERSON LA-UPPER LAFOURCHE LA-UPPER PLAQUEMINES LA-UPPER ST. BERNARD LA-UPPER TERREBONNE LA-WALTHALL MS-WASHINGTON LA-WEST BATON ROUGE LA-WEST FELICIANA LA-WILKINSON MS-

800 AM CDT TUE APR 4 2006

...A DRY START TO 2006 AND THE ONSET OF A DROUGHT FOR SOUTHEAST LOUISIANA AND COASTAL MISSISSIPPI...

THE FIRST THREE MONTHS OF 2006 HAVE COMBINED TO SET A RECORD FOR LOWEST RAINFALL AT BATON ROUGE AND NEW ORLEANS. THIS COMPARES TO THE VERY DRY STARTS OF 2000 AND 1962.

AT BATON ROUGE SINCE JANUARY 1ST THROUGH APRIL 3RD...ONLY 6.41 INCHES OF RAINFALL HAS BEEN MEASURED. NORMAL RAINFALL FOR THE SAME PERIOD IS 16.89 INCHES. THIS IS A DEFICIT OF 10.48 INCHES BELOW NORMAL. THE PREVIOUS DRIEST PERIOD WAS 2000...WHICH MEASURED 7.20 INCHES THROUGH APRIL 3RD.

AT NEW ORLEANS SINCE JANUARY 1ST THROUGH APRIL 3RD...6.74 INCHES OF RAINFALL WAS MEASURED AND COMPARES TO A NORMAL OF 17.09 INCHES...A DEFICIT OF 10.35 INCHES BELOW NORMAL. THE PREVIOUS DRIEST 3 MONTH PERIOD THROUGH APRIL 3RD WAS 6.81 INCHES IN 1962. IN ADDITION... 2000 HAD 7.09 INCHES AT NEW ORLEANS FOR THE SAME PERIOD.

SINCE JANUARY 1 2005...NEW ORLEANS HAS A RAINFALL DEFICIT OF 21.49 INCHES...DESPITE BIG RAINFALL EVENTS FROM HURRICANE CINDY AND HURRICANE KATRINA. AT BATON ROUGE...THE 15 MONTH DEFICIT FROM JANUARY 1 2005 IS AROUND 18.76 INCHES BELOW NORMAL.

THE REASON FOR THE UNUSUALLY DRY CONDITIONS AND THE ONSET OF A MODERATE AGRICULTURAL DROUGHT IS BELIEVED TO BE LINKED TO THE LA NINA PHENOMENON OF THE EQUATORIAL PACIFIC OCEAN. COOLER THAN NORMAL WATER TEMPERATURES ALONG THE EQUATOR IN THE EASTERN PACIFIC OCEAN ALTERS THE TRACKS OF STORM SYSTEMS TO WELL NORTH OF THE GULF STATES...THEREBY LIMITING THE OPPORTUNITIES FOR TYPICAL RAIN EPISODES. THE CURRENT LA NINA CYCLE IS CONSIDERED TO BE WEAK. COMPARABLE YEARS WITH SIMILAR LA NINA CONDITIONS SINCE 1950 INCLUDE 1960-1961...1984-1985...1995-1996...2001-2002. THIS YEAR IS THE SECOND PART OF A 2005-2006 CYCLE.

AS WE APPROACH THE UPCOMING HURRICANE SEASON...SEVERAL CORRELATIONS TO THE LA NINA AND ATLANTIC TROPICAL CYCLONE ACTIVITY WILL BE MADE. RECENT STUDIES INDICATE THAT THE LA NINA PHASE OF THE ENSO CYCLE IS TYPICALLY MORE ACTIVE...SLIGHTLY ABOVE NORMAL...THAN THE EL NINO COUNTERPART OF THE ENSO CYCLE. THE COMPARABLE OR ANALOG YEARS PREVIOUSLY MENTIONED AVERAGED 12 NAMED STORMS AND 7 HURRICANES IN THE ATLANTIC BASIN IN THE SECOND SEASON OF THE PHASE. ON AVERAGE IN THE
GULF OF MEXICO IN ANALOG YEARS...3 NAMED STORMS AND 2 HURRICANES TYPICALLY DEVELOP. WHILE THESE ARE STATISTICAL AVERAGES...THEY DO NOT FULLY REVEAL WHAT KIND OF ACTIVITY CAN BE EXPECTED IN THE UPCOMING SEASON NOR INDICATE AREAS OF HIGHER CHANCES OF LANDFALLING HURRICANES.

HISTORICALLY...SOUTHEAST LOUISIANA AND COASTAL MISSISSIPPI HAD SEVERAL TROPICAL STORMS AND HURRICANES OCCUR IN THE COMPARABLE YEARS. IN 1960...HURRICANE ETHEL HIT LOUISIANA AND MISSISSIPPI. IN 1985...HURRICANE ELENA STRUCK THE MISSISSIPPI COAST AND HURRICANE JUAN MEANDERED OVER SOUTH LOUISIANA FOR SEVERAL DAYS. THE 1995-1996 SEASONS HAD NO LANDFALLS IN LOUISIANA OR MISSISSIPPI. IN 2001... TROPICAL STORM ALLISON AFFECTED SOUTHEAST TEXAS...LOUISIANA AND MISSISSIPPI. IN 2002...AN ACTIVE SEASON SAW TROPICAL STORMS BERTHA...HANNA AND ISIDORE MAKE LANDFALL IN THE CENTRAL GULF STATES ALONG WITH HURRICANE LILI INTO SOUTH-CENTRAL LOUISIANA. FINALLY....THE 2005 SEASON SAW 10 NAMED STORMS AND 6 HURRICANES IN THE GULF OF MEXICO WITH HURRICANES CINDY...KATRINA AND RITA MAKING HISTORICAL LANDFALLS ON LOUISIANA AND MISSISSIPPI SHORES.

THE NATIONAL WEATHER SERVICE OFFICE IN SLIDELL WILL CONTINUE TO MONITOR THE TRENDS IN THE UPCOMING MONTHS REGARDING THE DROUGHT SITUATION. FOR MORE INFORMATION REGARDING THE NATION'S DROUGHT CONDITIONS...VISIT THE NATIONAL DROUGHT MONITOR WEBSITE AT HTTP://WWW.DROUGHT.UNL.EDU/DM/DRMON.GIF (ALL LOWER CASE). FOR ADDITIONAL INFORMATION ON LA NINA...VISIT THE CLIMATE PREDICTION CENTER WEBSITE AT HTTP://WWW.CPC.NCEP.NOAA.GOV (ALL LOWER CASE) AND THE CLIMATE DIAGNOSTIC CENTER WEBSITE AT HTTP://WWW.CDC.NOAA.GOV
(ALL LOWER CASE).

$$

24

[tailgater]

Well, aren't we just full of good news. j/j

Sounds like we should be prepare for at least a Hurricane or drought busting(flooding) TS

[Javlin]

Must have something to do with that May dry theory hmmm.....




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