Severe Thunderstorm Warning 229, NWS New Orleans, LA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS/BATON ROUGE LA
1120 AM CDT THU AUG 31 2000

ANOTHER ACTIVE WEATHER DAY IS SHAPING UP ACROSS MOST OF THE FORECAST
AREA FOR THIS AFTERNOON AND EVENING WITH HIGH HEAT INDICES AND
SEVERE THUNDERSTORMS EXPECTED.

THE UPPER LEVEL PATTERN IS SIMILAR TO YESTERDAY...A CUT-OFF LOW OVER
GA...AN ANTICYCLONE/RIDGE ACROSS E MEXICO INTO SE OK...AND A 250 MB
NORTHERLY WIND MAX FROM SW LA INTO THE W GULF. THE MAIN DIFFERENCE
IS THE SURFACE TROUGH HAS PUSHED W TO NEAR THE MS RIVER W OF KBTR...
ALLOWING DEEPER S FLOW IN THE LOW LEVELS. DEWPOINTS REMAIN VERY
HIGH...MAINLY IN THE 75 TO 80 DEGREE RANGE...EXCEPT FOR
EXCEPTIONALLY HIGH 82 READINGS AT KHUM AND KBTR. VISIBLE IMAGERY
SHOWS CUMULUS DEVELOPMENT IN THIS HIGH DEWPOINT CORRIDOR AND ACROSS
SW AL AND SE MS WHERE DEEPER MOISTURE IS PRESENT.

WILL UPDATE ZONES TO INCLUDE MENTION OF LOCALLY SEVERE THUNDERSTORMS
PER SWODY1 AND SPSNEW-THUNDERSTORM OUTLOOK. DOWNBURST WINDS AND HAIL
UP TO DIME SIZE WILL BE THE PRIMARY THREAT.

REGARDING THE HEAT ADVISORY...WILL LIKELY EXTEND THE HEAT ADVISORY
THROUGH FRIDAY IN THE AFTERNOON FORECAST PACKAGE WITH EXPECTED LOW
TEMPS AROUND 80 DEGREES AGAIN TONIGHT IN SE LA. EVEN SLIGHTLY COOLER
DAYTIME TEMPERATURES DUE TO SOUTH WIND WILL BE OFFSET BY THE HIGHER
DEWPOINTS...SO NO RELIEF IS IN SIGHT EXCEPT FOR THE COOLING
THUNDERSTORMS.

.NEW...NONE
LA...HEAT ADVISORY SE LA ZONES - LAZ058>070.
MS...NONE.

22

LAZ034>040-046>050-056>070-MSZ068>071-077-080>082-311900-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1046 AM CDT THU AUG 31 2000

...THERE IS A CHANCE OF SEVERE THUNDERSTORMS THIS AFTERNOON...

AN AREA OF LOW PRESSURE OVER THE LOWER MISSISSIPPI VALLEY IN
COMBINATION WITH INCREASING SOUTHEASTERLY FLOW WILL PRODUCE
SCATTERED THUNDERSTORMS DURING THE AFTERNOON.  SEA BREEZE AND LAKE
BREEZE BOUNDARIES WILL LIKELY FOCUS THE THUNDERSTORMS OVER THE
INLAND AREAS WITH SOME OF THE STORMS REACHING SEVERE LEVELS.

THE MAIN CONCERN WILL BE DAMAGING WIND GUSTS OF 45 TO 60 MPH...
MARBLE TO DIME SIZED HAIL...FREQUENT LIGHTNING AND BRIEF HEAVY
RAINFALL. THE PERIOD OF HIGHEST THREAT SHOULD ONSET AROUND 2 PM AND
CONTINUE THROUGH 830 PM. THE AREA OF CONCERN WILL BE ALL OF
SOUTHEAST LOUISIANA EAST OF THE ATCHAFALAYA RIVER AND SOUTHERN
MISSISSIPPI. MOVEMENT OF THE STORMS WILL VARY DEPENDING ON SEA
BREEZE INTERACTIONS1 BUT THE PREVAILING MOVEMENT SHOULD BE FROM THE
NORTH AT 10 TO 15 MPH.

FOR MORE WEATHER INFORMATION VISIT OUR WEB-SITE AT
WWW.SRH.NOAA.GOV/LIX (ALL LOWER CASE).

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1155 AM CDT THU AUG 31 2000

LAZ056>070-312300-
ASSUMPTION-LOWER JEFFERSON-LOWER LAFOURCHE-LOWER PLAQUEMINES-
LOWER ST BERNARD-LOWER TERREBONNE-ORLEANS-ST CHARLES-ST JAMES-
ST JOHN THE BAPTIST-UPPER JEFFERSON-UPPER LAFOURCHE-
UPPER PLAQUEMINES-UPPER ST BERNARD-UPPER TERREBONNE-
INCLUDING THE CITIES OF...GRAND ISLE...HOUMA...METAIRIE...NEW ORLEANS
1155 AM CDT THU AUG 31 2000

...A HEAT ADVISORY IS IN EFFECT THIS AFTERNOON...
...AFTERNOON HEAT INDICES 105 TO 115 DEGREES...

HIGH TEMPERATURES ARE EXPECTED TO BE IN THE 95 TO 100 DEGREE
RANGE AND HEAT INDICES ARE EXPECTED TO BE AT DANGEROUS LEVELS OF 105
TO 115 DEGREES. LOW TEMPERATURES TONIGHT WILL BE 80 DEGREES OR
HIGHER.

THE HEAT INDEX IS A MEASURE OF HOW HOT IT FEELS WHEN THE EFFECTS OF
HUMIDITY ARE COMBINED WITH THE TEMPERATURE. A HEAT INDEX OF 105
DEGREES IS THE LEVEL WHERE MANY PEOPLE BEGIN TO EXPERIENCE EXTREME
DISCOMFORT OR PHYSICAL STRESS. THE HEAT INDEX IS MEASURED UNDER
SHADY CONDITIONS...AND DIRECT EXPOSURE TO SUNLIGHT CAN INCREASE THE
HEAT INDEX AS MUCH AS 15 DEGREES.

EFFECTS CAN BE MINIMIZED BY REDUCING OUTDOOR ACTIVITIES...DRINKING
PLENTY OF WATER OR NON-ALCOHOLIC BEVERAGES...AND WEARING LIGHT-
COLORED CLOTHING. IF POSSIBLE...SPEND TIME IN AIR CONDITIONED
FACILITIES.

PETS CAN ALSO SUCCUMB TO THE EFFECTS OF EXCESSIVE HEAT. ENSURE PETS
HAVE ADEQUATE DRINKING WATER AND A SHADY PLACE TO REST. DO NOT KEEP
PETS IN CARS WITH WINDOWS ROLLED UP...EVEN PARTIALLY.

DO NOT LEAVE CHILDREN AND SMALL PETS IN CLOSED AUTOMOBILES.
TEMPERATURES INSIDE A CAR WITH THE WINDOWS UP CAN REACH OVER 150
DEGREES QUyICKLY...RESULTING IN HEAT STROKE AND DEATH FOR SMALL
CHILDREN AND PETS.

FOR MORE WEATHER INFORMATION PLEASE VISIT OUR WEB-SITE AT
WWW.SRH.NOAA.GOV/LIX (ALL LOWER CASE).