Severe Thunderstorm Warning 142, NWS New Orleans, LA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS/BATON ROUGE LA
225 PM CDT SAT JUL 22 2000

MODELS ARE IN GENERAL AGREEMENT IN HANDLING THE QUASI-STATIONARY LOW
LEVEL BOUNDARY IN PERSISTENCE THROUGH 48 HOURS AND BEYOND. DEEPENING
AMPLIFICATION OF RETROGRADING TROUGH AT H50 WILL INCREASE
INSTABILITY WITH COLD AIR ADVECTION...SHORT-WAVE PROGRESSIONS AND
VORTICITY ADVECTION TRENDS THROUGH TUESDAY. WILL BE GOING FAIRLY
CLOSE TO AVN WHICH IS A COMPROMISE OF THE OTHER MODELS AND CLOSER TO
SHORT-TERM TRENDS.

IN THE SHORT TERM...BELIEVE THE CONVECTION WILL BREAK OUT IN
WIDESPREAD COVERAGE GENERALLY FROM KMCB-KHUM EASTWARD. AS A RESULT
WILL HANDLE WITH A REMAINDER OF THIS AFTERNOON GROUPING TO ADDRESS
CONVECTIVE TRENDS AND SEVERITY. THEREAFTER...TEND TO COMPROMISE ON
MODEL AND CONTINUITY TEMPS AND POPS.

IN THE EXTENDED...REMARKABLY DIFFERENT PATTERN FROM TYPICAL SUMMER
WITH DEEP TROUGHING ALOFT OVER THE REGION WHICH SHOULD MAINTAIN GOOD
CHANCE POPS THROUGH THURSDAY. TEMPS WILL BE NEAR CLIMATOLOGY DURING
THE PERIOD.

MCB 70/93/67/91 2615    BTR 73/92/69/91 2625
MSY 77/92/75/91 2725    GPT 73/92/73/90 2715

.NEW...NONE.
LA...XNONE.
MS...NONE.
24

LAZ034>040-046>050-056>070-MSZ068>071-077-080>082-221930-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1020 AM CDT SAT JUL 22 2000

...THERE IS A CHANCE FOR SEVERE THUNDERSTORMS TODAY...

A STATIONARY FRONT EXTENDING FROM HATTIESBURG MISSISSIPPI TO
ALEXANDRIA LOUISIANA WILL BE THE FOCUS OF THUNDERSTORM DEVELOPMENT
DURING THE EARLY AFTERNOON HOURS. SEA AND LAKE BREEZES WILL ALSO
AID IN THUNDERSTORM DEVELOPMENT.

THE PRIMARY THREAT OF SEVERE WEATHER WILL BE DAMAGING WIND GUSTS OF
55 TO 65 MPH...DIME TO NICKEL SIZED HAIL AND FREQUENT DEADLY
LIGHTNING. ISOLATED WEAK TORNADOES CAN NOT BE RULED OUT THIS
AFTERNOON. RAINFALL WILL ALSO BE LOCALLY HEAVY BUT MOST STORMS SHOULD
MOVE STEADILY AT 15 TO 20 MPH. THE MAIN TIME OF SEVERE WEATHER THREAT
WILL BE FROM NOON THROUGH 5 PM MAINLY NORTH OF LAKE PONTCHARTRAIN AND
THE SOUTHERN MISSISSIPPI COUNTIES. A THREAT FOR SEVERE WEATHER WILL
EXIST SOUTH OF THE TIDAL LAKES GENERALLY FROM 2 PM THROUGH SUNSET.

IN ADDITION...THE HIGHLY UNSTABLE AIRMASS WILL BE CAPABLE OF
WATERSPOUT DEVELOPMENT IN THE COASTAL MARSHES AND WATERS DURING THE
LATE MORNING AND EARLY AFTERNOON HOURS. MARINERS SHOULD KEEP A
CLOSE EYE ON THE WEATHER IN THEIR AREA AND MOVE AWAY FROM ANY
WATERSPOUTS.

EMERGENCY MANAGERS AND LOCAL LAW ENFORCEMENT OFFICIALS SHOULD STAFF
ACCORDINGLY THIS AFTERNOON FOR A SEVERE WEATHER POTENTIAL. STORM
SPOTTERS MAY BE ACTIVATED THIS AFTERNOON IN SOME LOCATIONS. THE
GENERAL PUBLIC SHOULD PAY CLOSE ATTENTION TO THE WEATHER AND BE
PREPARED TO TAKE NECCESARY PRECAUTIONS SHOULD THREATENING WEATHER
DEVELOP. STAY TUNED TO LOCAL AND CABLE TV...LOCAL RADIO AND NOAA
WEATHER RADIO FOR STATEMENTS AND POSSIBLE WARNINGS THROUGHOUT THE
DAY.

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