Severe Thunderstorm Warning 47, NWS New Orleans, LA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS/BATON ROUGE LA
155 PM CDT THU JUL 4 2002

SCATTERED SHOWERS AND THUNDERSTORMS DEVELOPED EARLIER TODAY.
HOPEFULLY...THIS MEANS MOST OF THE ACTIVITY WILL DIE DOWN FOR THE
EVENING INDEPENDENCE DAY CELEBRATIONS. ONE FEATURE OF CONCERN IS
NOTED ON WATER VAPOR LOOPS...A STRENGTHENING VORT MAX/LOBE OVER
NORTHERN AND CENTRAL AL AND NORTHWEST MS WHICH IS MOVING SOUTH.
THUNDERSTORMS ARE INCREASING IN COVERAGE AND INTENSITY JUST AHEAD OF
A MID LEVEL DRY SLOT ACROSS EAST CENTRAL MS AND SOUTHWEST AL.
EXTRAPOLATION WOULD BRING THIS ACTIVITY DOWN TO THE MS GULF COAST
PEARL RIVER BASIN AREA DURING THE EVENING. WILL MONITOR INTENSITY OF
THE THUNDERSTORMS AS THEY APPROACH FROM THE NORTH...AS THIS PATTERN
WOULD SUPPORT STRONG DOWNBURST WINDS...ESPECIALLY WHERE THERE ARE
CELL MERGERS AND OUTFLOW BOUNDARY COLLISIONS. AM CURRENTLY THINKING
THE 40 PERCENT POPS WILL HOLD FOR MOST OF THE FORECAST AREA THE
REMAINDER OF TODAY...AND WILL RAISE POPS TO AT LEAST 40 PERCENT IN
THE NORTHEAST AND EAST ZONES FOR THIS EVENING. FOR THE LATE
AFTERNOON HOURS...INCREASED CLOUD DEBRIS FROM THE LARGE AREA OF
SCATTERED SHOWERS AND THUNDERSTORMS SHOULD KEEP MOST OF THE
THUNDERSTORMS BELOW STRONG TO SEVERE LEVELS.

THE MODELS ARE FAIRLY SIMILAR WITH THE BASIC PATTERN THE NEXT FEW
DAYS. THE UPPER LOW/TROUGH THAT HAS BEEN RESPONSIBLE FOR THE
FLOODING IN TEXAS IS FORECAST TO MOVE WEST INTO THE HIGH PLAINS AND
WEAKEN. AT THE SAME TIME...AN UPPER HIGH OVER THE MID MS VALLEY WILL
STRENGTHEN AND BUILD SLOWLY SOUTH AND WEST INTO THE CENTRAL AND
SOUTHERN PLAINS...MERGING WITH A MASSIVE STRONG UPPER HIGH WHICH
DEVELOPS OVER THE ROCKIES AND INTERMOUNTAIN WEST SUNDAY THROUGH
EARLY NEXT WEEK. THE POSITION OF THE UPPER HIGH...COUPLED WITH A
RETROGRADING UPPER TROUGH OVER THE NORTHEAST AND CENTRAL GULF OF
MEXICO...WILL CONTINUE TO BRING DISTURBANCES SOUTHWEST AND WEST
ACROSS THE CENTRAL GULF COAST REGION. A WEAK SURFACE LOW/TROUGH IS
EXPECTED TO APPROACH FROM THE EAST FRIDAY AND SATURDAY. RESULTANT
OFFSHORE WINDS WILL KEEP THE SEA BREEZE AT BAY...BUT UPPER LEVEL
ENERGY AND PRECIPITABLE WATER VALUES REMAINING HIGH / 1.8 TO AROUND
2 INCHES/ WILL CONTINUE A DECENT CHANCE OF CONVECTION FOR FRIDAY AND
SATURDAY. SOUTHEAST TO EAST SURFACE WINDS WILL RETURN FOR SUNDAY
INTO THE MIDDLE OF NEXT WEEK AS A STRENGTHENING MID ATLANTIC COAST
SURFACE HIGH PUMPS ATLANTIC MOISTURE INTO THE MIX. THIS WILL
MAINTAIN DECENT CHANCES OF SHOWERS AND THUNDERSTORMS OUT THROUGH DAY
SEVEN.

MCB 70/91/71/91 3424  BTR 72/91/73/92 2424
MSY 75/90/76/91 3524  GPT 72/90/73/91 4524

.NEW...NONE
LA...NONE.
MS...NONE.

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