South Louisiana Flood Event?

[PTrackerLA]

I've noticed that the NWS New Orleans has really become concerned about the potential flood event Thursday and Friday from Texas system. The GFS has consistently been showing QPF bullseyes right over south-central and eastern Louisiana into southern Miss for a few days now and I think they are beginning to take this seriously. Not so much in south central LA but southeast LA has substantial rainfall deficits for the year, and with a Flood Watch posted for Thursday and Friday I have a feeling this could be a serious episode. It will be interesting to see how this all unfolds. Check out these discussions, it sounds ominous:

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NEW ORLEANS LA
614 PM CDT WED MAY 2 2007

.UPDATE...THIS IS AN INTERIM UPDATE TO INFORM THE MEDIA OF OUR
INTENTIONS THROUGHOUT THIS EVENING. AFTER A LENGTHY DISCUSSION AND
MODEL REVIEW...WE HAVE OPTED TO HEIGHTEN THE NEXT 24-48 HOURS
SEVERE WEATHER AND FLASH FLOOD POTENTIAL ONSETTING THURSDAY
AFTERNOON AND CONTINUING THROUGH FRIDAY AFTERNOON. WE WILL BE IN
COORDINATION WITH THE STORM PREDICTION CENTER...THE
HYDROMETEOROLOGICAL PREDICTION CENTER IN WASHINGTON AND THE LOWER
MISSISSIPPI RIVER FORECAST CENTER TO COME INTO AGREEMENT WITH OUR
PRODUCT WORDING FORTHCOMING LATER THIS EVENING. WE ARE LAUNCHING
THE 00Z FLIGHT AT THIS TIME AND WILL BE ANALYZING THE 00Z UPPER
AIR CHARTS AROUND 8 PM. AROUND 9 PM...ANTICIPATE AN ENTIRE UPDATE
TO THE ZONE AND DIGITAL DATA PRODUCTS TO REFLECT A SIGNIFICANT
UPGRADE TO SEVERE WEATHER AND HEAVY RAINFALL THREAT BASED ON
SEVERAL MODELS AND LOCAL PRECIPITATION CALCULATOR OUTPUT ON MODEL
SOUNDINGS. THIS UNFOLDING SYNOPTIC PATTERN IS QUITE SIMILAR TO MAY
8 1995 AND CAN RIVAL THAT EVENT SOMEWHERE IN SOUTHEAST LOUISIANA
AND EXTREME SOUTHERN MISSISSIPPI. HOPEFULLY WITH THE LATER
ANALYSIS AND CONTINUED MONITORING OF ONGOING TRENDS WE SHOULD BE
ABLE TO PRODUCE SOME FORECASTED RAINFALL AMOUNTS AND CONVECTIVE
INTEGRITY VALUES IN ANOTHER AFD AND UPDATED HWO AROUND 9 PM.

NO CHANGES AT THIS TIME BUT WILL TRY TO HAVE EVERYTHING UPDATED
AND READY FOR THE EVENING NEWS CYCLE...PARTICULARLY FOR THE BATON
ROUGE AND NEW ORLEANS MEDIA MARKETS. THE THREAT SEEMS LESS LIKELY
FOR THE MISSISSIPPI GULF COAST AT THIS TIME...OR AT LEAST DELAYED
UNTIL LATER FRIDAY. /24



AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1006 PM CDT WED MAY 2 2007

.UPDATE...
HAVE COORDINATED WITH LCH...SPC...HPC AND LMRFC CONCERNING
ANTICIPATED SIGNIFICANT WEATHER EVENT ABOUT TO UNFOLD FOR THURSDAY
AND FRIDAY POTENTIALLY OVER THE FORECAST AREA. SUBSEQUENT SEVERE
WEATHER OUTLOOK WILL INCLUDE SLIGHT RISK SEVERE FOR SOUTHEAST
LOUISIANA AND PERHAPS PORTIONS OF COASTAL MISSISSIPPI FOR THURSDAY
INTO FRIDAY MORNING WITH APPROACH OF ONGOING MCS AND OUTFLOW
BOUNDARIES RE-IGNITING IN MAX DAYTIME HEATING TOMORROW. GREATER
CONCERN MAY BE HIGHLY EFFICIENT RAINFALL WITH VERY LARGE
ACCUMULATIONS BY FRIDAY EVENING. THE GFS IS INDICATING IN EXCESS
OF 5 INCHES...INCLUDING A 8.73 INCH BULLS-EYE CENTERED OVER ST
TAMMANY PARISH FOR FRIDAY MORNING. MANY FACTORS POINT TO FAVORABLE
CONDITIONS FOR SUCH.

RAN PRECIPITATION CALCULATOR/RICKS INDEX SCHEME USING GFS MODEL
SOUNDING OVER KBTR AREA VALID 18Z THURSDAY USING A LIFT OF 336K
LIFTED FROM 900 MB. OUTPUT INDICATES 94 PERCENT CHANCE OF
PRECIPITATION...29 PERCENT CHANCE SEVERE THUNDERSTORMS. FORECASTED
PRECIPITATION 1.92 INCHES WITH POTENTIAL 5.25 INCHES FOR TEMPS
BELOW 72F. CONVECTIVE GUST POTENTIAL 53KT/61 MPH...MARBLE TO PENNY
HAIL...TORNADO POTENTIAL UP TO EF1...SOUNDING VIL 57 YIELDING
PENNY HAIL...AR VIL OF THE DAY IS 56. ALL OF THIS LOOKS PLAUSIBLE
AND GIVEN THE APPEARANCE OF TRAIN ECHO AND SLOW MOVING CONVERGENT
BOUNDARIES...POTENTIAL AMOUNTS MAY BE A DOUBLE PUMP EPISODE...WITH
10.50 INCHES ACCUMULATIONS POSSIBLE LOCALLY DUE TO HIGH
EFFICIENCY. HENCE THE FLOOD WATCH ISSUANCE AT THIS TIME. TWENTY HOUR
LEAD TIME SHOULD ALLOW FOLKS TO TAKE APPROPRIATE PREPAREDNESS
MEASURES IN THE MORNING BEFORE RAINS AND SEVERE WEATHER ONSETS.

HAVE UPDATED QPF...POP AND WEATHER GRIDS TO REFLECT ABOVE
RATIONALE. LEFT TEMPERATURES AND WIND GRIDS ALONE AT THIS TIME.
PRODUCTS OUT SHORTLY.


...FLOOD WATCH IN EFFECT FROM THURSDAY EVENING THROUGH FRIDAY
AFTERNOON...

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* FLOOD WATCH FOR PORTIONS OF SOUTHEAST LOUISIANA AND SOUTHERN
MISSISSIPPI...INCLUDING THE FOLLOWING AREAS...IN SOUTHEAST
LOUISIANA...ASCENSION...ASSUMPTION...EAST BATON ROUGE...EAST
FELICIANA...IBERVILLE...LIVINGSTON...LOWER JEFFERSON...LOWER
LAFOURCHE...LOWER PLAQUEMINES...LOWER ST. BERNARD...LOWER
TERREBONNE...ORLEANS...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...
WASHINGTON...WEST BATON ROUGE AND WEST FELICIANA. IN SOUTHERN
MISSISSIPPI...AMITE...HANCOCK...HARRISON...JACKSON...PEARL
RIVER...PIKE...WALTHALL AND WILKINSON.

* FROM THURSDAY EVENING THROUGH FRIDAY AFTERNOON

* A STRONG UPPER LEVEL DISTURBANCE MOVING ACROSS TEXAS THIS
EVENING WILL BE MOVING SLOWLY OVER LOUISIANA THURSDAY...AND
SOUTHERN MISSISSIPPI BY FRIDAY AFTERNOON. A MOISTURE RICH
SOUTHERLY FLOW WILL PERSIST AND EVEN INCREASE IN STRENGTH
THURSDAY NIGHT OVER THE AREA. RAINFALL RATES OF TWO INCHES OR
MORE PER HOUR MAY BE COMMON CAUSING PONDING OF WATER TO OCCUR
RATHER QUICKLY.

SOME NUMERICAL FORECAST MODELS ARE INDICATING COPIOUS RAINFALL
AMOUNTS THAT MAY MATERIALIZE...INCLUDING ACCUMULATIONS BETWEEN 5
AND 10 INCHES WITHIN SIX HOUR PERIODS. IF THIS OCCURS...THEN
FLOODING CAN ENSUE AND POSSIBLY BECOME EXTENSIVE. A LOCAL
RAINFALL FORECASTING TECHNIQUE THAT HAS BEEN EFFECTIVE IN ITS
APPLICATIONS ALSO SUPPORTS POTENTIAL RAINFALL ACCUMULATIONS OF 5
TO 10 INCHES ONSETTING THURSDAY AFTERNOON THROUGH FRIDAY
AFTERNOON.

HISTORICALLY...MAY 3RD MARKS A SIGNIFICANT FLOOD DATE FOR THE
CITY OF NEW ORLEANS FROM 1978...WHEN WIDESPREAD FLOODING
OCCURRED DUE TO A SLOW MOVING AND NEARLY STATIONARY COLD FRONT
NEAR THE CITY. ON MAY 8TH AND 9TH...HISTORIC HEAVY RAINS
PRODUCED AS MUCH AS 24 INCHES OF RAINFALL IN TWO DAYS OVER
SOUTHEAST LOUISIANA AND SOUTHERN MISSISIPPI. THIS CURRENT
WEATHER SITUATION RESEMBLES THE WEATHER PATTERN OF MAY 1995.

[Ptarmigan]

The radar is quiet, but it's deceptive. All I can say is YIKES! Everyone in South Louisiana must keep an eye on the weather. Could be the biggest since Hurricane Katrina. Our storm will be the rainmaker for Sout Louisiana. We're under it right now.

[CrazyC83]

Could it be a "homegrown Katrina"?

[PTrackerLA]

It doesn't look like we'll be getting too much rain at the moment as the storms to our west have turned into a predominately moderate rain area with a few embedded thunderstorms. Flooding will only occur if storms redevelop over South LA tonight and begin to train.