Severe Thunderstorm Warning 12, NWS New Orleans, LA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS/BATON ROUGE LA
230 AM CST WED MAR 15 2000

ETA IS MODEL OF CHOICE WITH BEST INITIALIZATION. 500 TROF OVER SOUTH
TEXAS WILL MOVE NE ACROSS THE WATCH AREA THROUGH 40 HOURS. STRONG
DYNAMICS WILL PRECEDE THE TROF AS IT MOVES EASTWARD. STRONG OMEGA
WILL REMAIN OVER THE AREA THROUGH 36 HOURS WITH STRONGEST UPWARD
MOTION TODAY AND EARLY TONIGHT. AREA REMAINS IN THE RIGHT REAR OF
THE JET THROUGH TONIGHT. ATMOSPHERE IS TROPICAL AN NEAR SATURATION
AND IS EXPECTED TO CONTINUE TO BECOME MORE UNSTABLE AS UPPER TROF
APPROACHES. A SOUTH BY SOUTHEAST LOW LEVEL JET OF 40 KNOTS ALREADY
IN PLACE OVER THE AREA. A SQUALL LINE EXTENDING FROM OFF THE
SOUTHWEST LOUISIANA COAST TO NORTHEAST MEXICO IS MOVING EAST IN
RESPONSE TO THE UPPER TROF OVER SOUTHERN TEXAS. THIS HAS THE
POTENTIAL OF CUTTING OFF MOISTURE MOVING ONSHORE AND SIGNIFICANTLY
REDUCING PRECIPITATION. GUIDANCE LOOKS REASONABLE AND WILL MAKE ONLY
SMALL ADJUSTMENTS. THE POTENTIAL REMAINS .50 TO .75 INCH OF RAINFALL
ACROSS THE AREA WITH LOCALLY HEAVIER AMOUNTS.

QPF DISCUSSION...UTILIZED THE PRECIPITATION CALCULATOR METHODOLOGY
UPON A SPECIAL TEST 06Z KSIL RELEASE. LOW LEVEL THETAE VALUES WERE
AT 322K WHICH WAS ANTICIPATED FROM YESTERDAY'S DISCUSSION BUT IN A
DEEPER LAYER THAN WHAT MODELS INDICATED. LATEST ETA RUNS SHOWED A
325K TROPOPAUSE FOLD CONNECTING WITH THE LOWER LEVEL THETAE BULGE
FOR THE 18Z-00Z TIMEFRAME.

OUTPUT FROM PCPN CALCULATOR...USING 325K AT 860MB...POP 69%...PCPN
0.66 INCHES...POTL PCPN 2.40 INCHES FOR SURFACE TEMPS BELOW
66F...FMAP 0.58 INCHES...RI=100...POSVR 0%...CONVECTIVE GUSTS
31-41KTS...HAIL AND TOR THREAT NIL.

IT WOULD SEEM WITH ESE FLOW ALONG THE COAST...THE BEST LOCATION FOR
HEAVIEST RAINFALL WOULD BE THE PARISHES SOUTH OF THE TIDAL
LAKES...NAMELY THE NEW ORLEANS METRO AREA SOUTHWARD TO THE COASTAL
MARSHES. THIS AREA SHOULD SEE 1 TO 2 INCHES THROUGH THURSDAY
AFTERNOON. THE 0.66" OUTPUT IS REASONABLE FOR LOCATIONS FARTHER N
AND W OF THE METRO AREA.

MCB 70/60/73/50 +874
BTR 70/62/75/55 +874
MSY 72/64/74/58 +873
BIX 70/65/70/58 +883

.NEW...SMALL C.RAFT ADVISORY KPQL TO K7R3.
LA...NONE
MS...NONE.

23/24

LAZ034>040-046>050-056>070-MSZ068>071-077-080>082-151900-

THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS/BATON ROUGE LA
1045 AM CST WED MAR 15 2000

NUMEROUS SHOWERS ALONG WITH A FEW EMBEDDED THUNDERSTORMS WILL AFFECT
THE ENTIRE FORECAST AREA THROUGH TONIGHT.  THIS IS THE RESULT OF AN
UNSTABLE AND MOISTURE RICH AIRMASS COVERING ALL OF SOUTHEAST
LOUISIANA AND SOUTHERN MISSISSIPPI.  THE PRIMARY THREAT FROM ANY
THUNDERSTORMS WILL BE BRIEF PERIODS OF HEAVY RAIN...FREQUENT
LIGHTNING AND GUSTY WINDS.  THE THREAT OF RAIN SHOULD BEGIN TO
DIMINISH ACROSS THE FORECAST AREA BY THURSDAY AS THE SHOWER AND
THUNDERSTORM ACTIVITY SHIFTS TOWARD THE EAST.

FOR MORE INFORMATDION...VISIT THE NEW ORLEANS/BATON ROUGE NATIONAL
WEATHER SERVICE FORECAST OFFICE WEB SITE AT WWW.SRH.NOAA.GOV/LIX
(ALL LOWER CASE LETTERS).

SPSNEW
LAZ034>040-046>050-056>070-MSZ068>071-077-080>082-152100-

THUNDERSTORM OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS/BATON ROUGE LA
100 PM CST WED MAR 15 2000

THE ATMOSPHERE OVER MUCH OF SOUTHEAST LOUISIANA AND SOUTHERN
MISSISSIPPI HAS CONTINUED TO DESTABILIZE DURING THE LAST COUPLE OF
HOURS.  THIS HAS RESULTED IN AN INCREASE IN THUNDERSTORM POTENTIAL
ACROSS THE FORECAST AREA THROUGH TONIGHT.  THE BEST CHANCE FOR
THUNDERSTORM ACTIVITY IS ALONG COASTAL SECTIONS PRIMARILY NEW
ORLEANS SOUTHWARD.  THE PRIMARY THREAT FROM THESE THUNDERSTORMS
REMAINS BRIEF PERIODS OF HEAVY RAIN...FREQUENT LIGHTNING AND GUSTY
WINDS.  HOWEVER...A FEW OF THESE THUNDERSTORMS MAY APPROACH SEVERE
THRESHOLDS THIS AFTERNOON LEADING INTO TONIGHT WITH THE GREATEST
THREAT BEING SMALL HAIL WITH STRONG DAMAGING WINDS.

FOR MORE INFORMATION...VISIT THE NEW ORLEANS/BATON ROUGE NATIONAL
WEATHER SERVICE FORECAST OFFICE WEB SITE AT WWW.SRH.NOAA.GOV/LIX
(ALL LOWER CASE LETTERS).