Tornado Warning 53, NWS New Orleans, LA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
315 PM CDT FRI APR 29 2005

.DISCUSSION...

STILL SOME QUESTIONS IN THE AIR THIS AFTERNOON...AS MODELS CONTINUE
TO DISAGREE ON FRONTAL POSITION FOR THE WEEKEND...AND INGREDIENTS
FOR CONVECTION TONIGHT INTO TOMORROW COME TOGETHER.  SATELLITE AND
SURFACE TRENDS ARE SHOWING STRONG LLJ ACROSS THE AREA...AND DECENT
MOISTURE ADVECTION TAKING PLACE IN THE LOW-MID LEVELS OF THE
ATMOSPHERE.  EXPECT THIS LLJ TO REMAIN OVER THE REGION INTO THE
EARLY OVERNIGHT HOURS...AS DEEPENING LOW IN TEXAS BEGINS TO EJECT
INTO THE TENNESSEE AND OHIO VALLEYS.  AMPLE MOISTURE AND HEAT
TRANSPORT WILL CONTINUE DUE TO THIS LLJ...AS SHARP FRONTAL BOUNDARY
SLIDES INTO THE CENTRAL GULF REGION.  HOWEVER...IT APPEARS THAT SOME
WEAK CAPPING WILL STILL BE IN PLACE IN THE MID-UPPER LEVELS.  THIS
SHOULD INHIBIT DEVELOPMENT OVER THE AREA UNTIL SOMETIME AFTER
MIDNIGHT.  EXPECT ONLY ISOLATED SEVERE THREAT IN THE AREA...AS BEST
FORCING QUICKLY PULLS TO THE NORTHEAST...AS THE LOW EJECTS INTO THE
TENNESSEE VALLEY.  HOWEVER...WE WILL BE IN A REGION OF GENERAL
ASCENT AS RIGHT ENTRANCE REGION OF 100KT JET STREAK MOVES ACROSS THE
LOWER MISSISSIPPI VALLEY.  EXPECT BOWING SEGMENTS TO BE THE MAIN
THREAT TONIGHT DUE TO DEEP UNIDIRECTIONAL FLOW AND DRY SLOT IN THE
MID TO UPPER LEVELS.

GOING INTO TOMORROW AND TOMORROW NIGHT...HAVE DECIDED TO GO WITH A
BLEND OF THE GFS/NAM.  WILL KEEP FRONT OVER THE NEARSHORE COASTAL
WATERS...WITH HIGHEST POPS OVER THE COASTAL WATERS.
HOWEVER...EXPECT SOME AFTERNOON CONVECTIVE DEVELOPMENT OVER COASTAL
SECTIONS OF LOUISINA...AS LOW LEVEL FORCING AND AMPLE HEAT AND
MOISTURE REMAIN IN THE REGION.  FARTHER TO THE NORTH...STRONGER
SUBSIDENCE AND CAPPING WILL INHIBIT CONVECTIVE DEVELOPMENT IN THE
AFTERNOON AND EVENING HOURS.

SUNDAY AND MONDAY...SURFACE AND UPPER LEVEL RIDGING WILL DOMINATE
THE AREA...WITH STRONG SUBSIDENCE AND WARMER TEMPERATURES.  THE HIGH
WILL BEGIN TO SHIFT TO THE EAST ON TUESDAY...ALLOWING THE FRONTAL
BOUNDARY OVER THE NORTHERN GULF TO SWING BACK ACROSS THE CWA AS A
WARM FRONT.  THIS FRONT WILL STALL OVER THE REGION ON WEDNESDAY...AS
A LOW IN TEXAS SWINGS THROUGH THE NORTHERN GULF OF MEXICO AND STRONG
RIDGING BECOMES ENTRENCHED OVER THE MIDWEST AND GREAT LAKES.  IT
APPEARS THAT A SERIES OF WEAK IMPULSES WILL RIDE ALONG THE FRONT
THROUGH THE WEEKEND.  DUE TO THIS...AM CONCERNED ABOUT HEAVY
RAINFALL POTENTIAL WITH THIS SYSTEM.  WILL LEAVE CHANCE POPS IN
THROUGH SATURDAY...DUE TO OVERALL UNCERTAINTY IN TIMING OF WEAK
IMPULSES.  TEMPERATURES WILL REMAIN NEAR NORMAL THROUGH THE PERIOD
AS OVERALL ZONAL FLOW DOMINATES THE REGION.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  66  74  50  77 /  50  30  20   0
BTR  68  75  53  79 /  40  30  20   0
MSY  73  77  59  78 /  40  50  30   0
GPT  72  76  56  76 /  50  60  30   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
MS...NONE.
SE LA AND MS COASTAL WATERS...NONE.

&&

32

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1000 PM CDT FRI APR 29 2005

LAZ034>040-046>050-056>070-MSZ068>071-077-080>082-301100-
AMITE-ASCENSION-ASSUMPTION-EAST BATON ROUGE-EAST FELICIANA-HANCOCK-
HARRISON-IBERVILLE-JACKSON-LIVINGSTON-LOWER JEFFERSON-LOWER
LAFOURCHE-LOWER PLAQUEMINES-LOWER ST. BERNARD-LOWER TERREBONNE-
ORLEANS-PEARL RIVER-PIKE-POINTE COUPEE-ST. CHARLES-ST. HELENA-ST.
JAMES-ST. JOHN THE BAPTIST-ST. TAMMANY-TANGIPAHOA-UPPER JEFFERSON-
UPPER LAFOURCHE-UPPER PLAQUEMINES-UPPER ST. BERNARD-UPPER
TERREBONNE-WALTHALL-WASHINGTON-WEST BATON ROUGE-WEST FELICIANA-
WILKINSON-
1000 PM CDT FRI APR 29 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL AND SOUTHEAST
LOUISIANA AND EXTREME SOUTHWEST...SOUTH CENTRAL AND COASTAL
MISSISSIPPI.

.DAY ONE...REMAINDER OF TONIGHT

A DEEPENING AREA OF LOW PRESSURE OVER SOUTHEAST ARKANSAS AND
NORTHERN MISSISSIPPI WILL CONTINUE PUSHING INTO THE TENNESSEE VALLEY
TONIGHT. A TRAILING COLD FRONT WILL SLIDE INTO SOUTH MISSISSIPPI AND
SOUTHEAST LOUISIANA AS THIS LOW PULLS EAST. AMPLE WARMTH AND
MOISTURE...COMBINED WITH THE APPROACHING FRONT WILL ALLOW A LINE OF
THUNDERSTORMS TO DEVELOP TONIGHT. A FEW OF THE THUNDERSTORMS COULD
BECOME SEVERE AT TIMES. THE MAIN THREAT FROM THESE THUNDERSTORMS IS
EXPECTED TO BE DAMAGING WINDS AND HAIL.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A FEW STRONG TO LOCALLY SEVERE THUNDERSTORMS WILL CONTINUE OVER THE
OFFSHORE COASTAL WATERS SATURDAY MORNING...BUT THE THREAT OF
THUNDERSTORMS WILL BE OVER ACROSS SOUTHEAST LOUISIANA AND SOUTH
MISSISSIPPI...AS HIGH PRESSURE BUILDS IN FOR THE WEEKEND. THERE IS
THE POSSIBILITY THAT A FEW WEAK THUNDERSTORMS COULD DEVELOP OVER
COASTAL SECTIONS OF LOUISIANA SUNDAY AFTERNOON...AS THE COLD FRONT
STALLS IN THE COASTAL WATERS.

ANOTHER THREAT OF THUNDERSTORMS WILL RETURN TUESDAY AND WEDNESDAY AS
WARM...MOIST AIR FROM THE GULF OF MEXICO RETURNS TO THE REGION.

.SPOTTER INFORMATION STATEMENT...

THE ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS AND EMERGENCY
MANAGEMENT PERSONNEL...IN SUPPORT OF SEVERE WEATHER OPERATIONS...IS
NOT REQUESTED AT THIS TIME.

8