Severe Thunderstorm Warning 4, NWS New Orleans, LA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS/BATON ROUGE LA
945 PM CST SUN JAN 23 2000

DECIDED TO INCREASE TONIGHTS RAIN CHANCES TO 60 PERCENT FOR RAIN IN
SW MS AND 70 PERCENT FOR SHOWERS AND THUNDERSTORMS ELSEWHERE AS AREA
OF CONVECTION CONTINUES TO BLOSSOM FROM NEAR AND SOUTH OF KBTR TO
THE NORTH SHORE OF LAKE PONTCHARTRAIN. AREA SHOULD SPREAD SOUTH AND
EAST BEFORE ENDING BY DAYBREAK.

905 PM DISCUSSION...

SCATTERED THUNDERSTORMS HAVE BEEN SLOWLY DECREASING IN NUMBER...BUT
A FEW STRONG STORMS CONTINUE. ONE CELL SOUTH OF LAFITTE RECENTLY HAD
A VIL OF 47...BUT WAS MOVING ESE OVER MARSHLAND AND SWAMPS.
INTERESTINGLY...THERE HAS BEEN VARIABLE MOVEMENT OF THUNDERSTORMS
WITH LEFT MOVERS AND RIGHT MOVERS DEVIATING FROM THE MEAN DUE EAST
MOVEMENT. SO FAR...NO REPORTS OF STRONG WINDS OR HAIL.

THE DECREASE IN THUNDERSTORM COVERAGE SHOULD BE A TEMPORARY LULL
WITH THE APPROACH OF A VERY POTENT 500 MB SHORTWAVE TROUGH WITH -30
CELSIUS TEMPS IN NE OKLAHOMA AND A 150 KNOT 250 MB JET MAX OVER NW
TEXAS. STRONG PVA AND THE LEFT FRONT EXIT REGION OF THE UPPER JET IS
ACTING TO CAUSE AN INCREASE IN LIGHT RAIN JUST SOUTH OF THE 850 MB
COLD FRONT OVER CENTRAL MS. THE 925 MB COLD FRONT WAS ANALYZED ABOUT
HALFWAY BETWEEN KJAN AND KSIL IN EXTREME S MS WITH THE SURFACE FRONT
FARTHER SOUTH FROM JUST S OF KLFT TO JUST N OF KSIL TO JUST N OF
KMOB.

WITH SURFACE CONVERGENCE BECOMING LESS AND LESS...WILL LOOK NEAR THE
925 MB FRONT FOR ADDITIONAL SHOWER AND ISOLATED THUNDER DEVELOPMENT
THE NEXT SEVERAL HOURS. RADAR LOOPS SHOW THIS OCCURRING AT THIS TIME
WITH RAPIDLY INCREASING SHOWERS ALONG I-12 BETWEEN KBTR AND KSIL AND
W OF KBTR ON I-10. CURRENT ZONE FORECAST HAS 50 PERCENT POPS ACROSS
THE BOARD AND THIS STILL LOOKS ABOUT RIGHT FOR THE REMAINDER OF
TONIGHT. UVV ASSOCIATED WITH THE UPPER TROUGH AND JET SHOULD WEAKEN
LATE TONIGHT...SO EXPECT CLEARING SKIES DURING THE MID TO LATE
MORNING HOURS MONDAY WITH BREEZY TO WINDY CONDITIONS DEVELOPING IN
THE WAKE OF THE FRONT.

ONLY OTHER FORECAST PROBLEM IS FOG. VERY LIGHT WINDS AND HIGH TEMPS
AND DEWPOINTS OVER COOLER WATER BODIES IS PRODUCING AREAS OF DENSE
FOG S OF I-10 IN COASTAL MS AND AN OFF-DUTY OBSERVER DRIVING ON I-10
WEST OF KENNER ON THE BONNET CARRE SPILLWAY REPORTED VISIBILITY
BETWEEN ONE-QUARTER AND ONE-HALF MILE. FORTUNATELY...THIS WILL BE
SHORT-LIVED WITH THE FRONT COMING THROUGH...SO DO NOT EXPECT T$O
ISSUE A DENSE FOG ADVISORY.

.NEW...SMALL CRAFT ADVISORY KPQL TO K7R3 INCLUDING LAKES
PONTCHARTRAIN AND MAUREPAS.
LA...NONE.
MS...NONE.

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