689  
FXUS64 KLIX 242214  
AFDLIX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW ORLEANS LA  
514 PM CDT THU MAY 24 2018  
   
DISCUSSION
 
CONVECTION HAD FAR GREATER COVERAGE TODAY SEABREEZE  
THAN THE LAST FEW DAYS FINALLY. SEABREEZE/LAKEBREEZE INITIATED  
QUICKLY AND THEN MOST EVERYTHING BECOME DOMINATED BY OUTFLOW AND  
COLLIDING BOUNDARIES. DUE TO THE GREATER COVERAGE HIGHS WERE  
DEFINITELY IMPACTED WITH MOST PLACES ONLY IN THE 80S.  
 
THE RIDGE OVER THE CONUS JUST EAST OF THE MS WILL CONTINUE TO BREAK  
DOWN AS A TROUGH WORKS ACROSS THE ENTIRE MS VALLEY. WITH THAT AND  
INCREASING MOISTURE CONVECTION WILL HAVE VERY LITTLE DIFFICULTY  
DEVELOPING AGAIN TOMORROW. MUCH LIKE TODAY THE SEABREEZE/LAKEBREEZE  
SHOULD INITIATE SOMEWHAT EARLY AND THEN CONVECTION WILL ONCE AGAIN  
BE DICTATED BY OUTFLOW AND COLLIDING BOUNDARIES. OVERALL EXPECT MOST  
OF THE AREA TO AT LEAST SEE SOME RAIN OR BE FAIRLY CLOSE TO SEEING  
RAIN AND WHILE THAT MAY BE THE CASE AT ANY GIVEN POINT NOT EXPECTING  
MUCH MORE THAN SCATTERED COVERAGE.  
 
SATURDAY COULD BE A REPEAT OF FRIDAY WITH POSSIBLY EVEN SLIGHTLY  
GREATER COVERAGE OF RAIN. ONCE AGAIN CONVECTION WILL BE DRIVEN  
DIURNALLY AS OUR TROPICAL SYSTEM WE ARE WATCHING MAY ALREADY BE OR  
JUST STARTING TO TAKE SHAPE IN THE SOUTHERN GULF.  
 
NOW AS WE LOOK INTO SUNDAY AND THE FIRST HALF OF NEXT WEEK, SOME  
GOOD NEWS, SOME BAD NEWS. FIRST THE BAD NEWS MODELS HAVE STARTED  
COMING IN-LINE AND ARE INDICATING A BETTER CHANCE OF SEEING SOME  
SIGNIFICANT IMPACTS ACROSS PORTIONS OF THE AREA. GOOD NEWS THE  
MODELS HAVE STARTED TO COME IN-LINE AND ARE INCREASING THE  
CONFIDENCE OF WHERE IMPACTS COULD BE.  
 
OVER THE LAST 12-24 HOURS THE MODELS HAVE STARTED TO CONVERGE A  
LITTLE AND NOW INDICATE A TRACK MORE TOWARDS THE NORTH-CENTRAL LA  
WITH 90L. THEY CONTINUE TO SLOW THE SYSTEM AS IT GETS TRAPPED IN A  
VERY WEAK STEERING PATTERN SUNDAY THROUGH TUESDAY. FORECAST HAS IT  
BASICALLY JUST HEADING NORTH SLOWLY ALONG A SLIGHT WEAKNESS OVER THE  
LOWER MS VALLEY AND TN VALLEY LEFT OVER BY THE DEPARTING NORTHERN  
STREAM TROUGH. LATEST THINKING IS THAT 90L WILL EVENTUALLY BECOME A  
TROPICAL CYCLONE THIS WEEKEND AND SLOWLY APPROACH THE COAST OF  
SELA/MS/AL SOMETIME MONDAY.  
 
ONE OTHER CONCERNING THING IS NOW CONDITIONS COULD IMPROVE ENOUGH TO  
ALLOW FOR SLIGHTLY MORE STRENGTHENING THEN PREVIOUSLY THOUGHT. COME  
LATE SATURDAY AND THROUGH SUNDAY NIGHT THE SHEAR WILL WEAKEN AND  
MODELS ARE INDICATING THAT THERE COULD BE A FAVORABLE OUTFLOW  
CHANNEL TO THE NORTH OF THE SYSTEM. IN ADDITION THE WATER IS FAIRLY  
WARM ACROSS THE CENTRAL AND NORTH-CENTRAL GULF WHICH IS WHERE THIS  
SYSTEM WILL TRACK. LAST DRIER AIR IS NOT SHOWING UP AS MUCH IN THE  
WV AS YESTERDAY AND THE SYSTEM COULD BE INSULATED FROM DRY AIR. WITH  
THAT WE CAN NOT RULE OUT A STRONG TS POSSIBLY EVEN APPROACHING A LOW  
END HURRICANE APPROACHING THE COAST. THIS WOULD INCREASE THE IMPACTS  
FROM WIND AND TIDES BUT WE STILL STILL FEEL THAT HEAVY/FLOODING RAIN  
IS THE GREATEST CONCERN ESPECIALLY OVER COASTAL MS.  
 
AS FOR THE RAIN THIS IS STILL TRICKY AS WE APPEAR TO BE IN THE  
GRADIENT. OVERALL ACROSS SELA AND SOUTHERN/COASTAL MS WE COULD SEE  
RAIN RANGE FROM JUST OVER AN INCH IN THE WEST TO OVER 8 INCHES AND  
POSSIBLY A GOOD BIT MORE IN THE EAST. EVEN THOUGH CONFIDENCE HAS  
INCREASED IN THE FORECAST WE WOULD LIKE TO NOT GET TOO DETAILED AT  
THIS TIME ON THE WHERE THE CUT OFF WOULD BE FOR HEAVY POSSIBLY FLASH  
FLOODING RAIN AND THE TYPICAL DAYTIME THUNDERSTORMS. THAT SAID WE  
FEEL THE BEST LOCATION FOR HEAVY RAIN WILL BE EAST OF I-55 WITH A  
FOCUS LIKELY OVER COASTAL MS WHERE OVER 10 INCHES IS NOT OUT OF THE  
QUESTION. WIDESPREAD 4-8 IS EXPECTED WITH SOME LOCATIONS POSSIBLY  
SEEING MORE THAN DOUBLE THAT WHEN EVERY THING IS SAID AND DONE (YES  
MORE THAN 16 INCHES IS POSSIBLE IF THE SYSTEM MOVES AS SLOW AS  
EXPECTED AND OVER COASTAL MS/SELA).  
 
OBVIOUSLY WITH A POSSIBLE STRONGER STORM THE IMPACT FROM WINDS AND  
TIDES/SURGE IS HIGHER ESPECIALLY NEAR THE COAST OF MS AND SELA EAST  
OF THE MS RIVER. WITH THE CURRENT FORECAST APPROACHING THE MS COAST  
AND APPROACHING SLOWLY WATER WILL PILE UP ALONG THE COAST OF SELA  
EAST OF THE MS RIVER ALONG WITH LAKE P AND ACROSS COASTAL MS. AT  
THIS TIME WE ARE FORECASTING A SLIGHTLY CONSERVATIVE (DUE TO  
UNCERTAINTY) 1-3 FEET OF SURGE IN THE LAKE AND 2-4 ACROSS COASTAL MS  
AND THE THE EAST FACING COASTS OF SELA. OTHER ISSUE TO KEEP AN EYE  
ON SURGE WISE WOULD BE INSIDE BARATARIA BAY WHERE STRONG PERSISTENT  
WINDS OUT OF THE WEST COULD PILE UP WATER ON THE WEST SIDE OF  
PLAQUEMINES PARISH. WINDS WOULD HAVE THE GREATEST IMPACT RIGHT ALONG  
THE COAST AND LIKELY DECREASE PRETTY QUICKLY INLAND AND ESPECIALLY  
TO THE NORTHWEST OF THE SYSTEM.  
 
BIGGEST CONCERN WITH THESE IMPACTS IS TRACK. CURRENT TRACK IS NOT  
THE GREATEST NEWS FOR OUR AREA. A SLIGHT JOG TO THE WEST POSSIBLY  
OVER SELA WITH A SIMILAR SLOW FORWARD MOTION WOULD INCREASE PRETTY  
MUCH ALL OF THE IMPACTS FOR A GOOD PORTION OF THE CWA WITH FLOODING  
RAIN A SIGNIFICANT ISSUE. A JOG TO THE EAST STAYING TOWARDS AL WILL  
LOWER MOST OF THE IMPACT'S FOR PRETTY MUCH ALL OF THE CWA EXCEPT  
COASTAL MS. A TRACK EVEN FURTHER EAST (NOT OUT OF THE QUESTION SINCE  
WE STILL DONT EVEN HAVE A DEVELOPED SYSTEM YET) WOULD PRETTY MUCH  
TAKE ALL OF THE IMPACTS OUT OF OUR AREA.  
 
WE DO WANT TO POINT OUT THAT NOTHING HAS EVEN DEVELOPED YET AND  
MODELS WILL STRUGGLE AND SWING SIGNIFICANTLY UNTIL THERE IS  
SOMETHING DEVELOPED. SO CONTINUE TO FOLLOW THE FORECAST AS THIS  
EVOLVES THIS HOLIDAY WEEKEND.  
 
IF THIS SYSTEM DEVELOPS INTO A TROPICAL CYCLONE (WHICH WE  
THINK IT EVENTUALLY WILL) AND ATTAIN TROPICAL STORMS STATUS IT WOULD  
BE NAMED ALBERTO. HURRICANE HUNTERS ARE SCHEDULED TO INVESTIGATE  
TOMORROW IF THERE IS SOMETHING TO INVESTIGATE. IN ADDITION WE WILL  
BEGIN 6 HOURLY BALLOON LAUNCHES AT 18Z TOMORROW. /CAB/  
 

 
   
MARINE
 
WINDS ARE STILL ON THE LIGHTER SIDE AND LOOK TO BE  
THROUGH FRIDAY NIGHT AND POSSIBLY INTO SATURDAY WITH OUR SYSTEM  
FINALLY MOVING THROUGH THE SOUTHERN GULF. MODELS HAVE COME INTO  
AGREEMENT WITH A LIKELY TROPICAL CYCLONE MOVING INTO THE NORTH-  
CENTRAL GULF LATE THIS WEEKEND EARLY NEXT WEEK. WINDS WILL BEGIN TO  
RESPOND SUNDAY OUT OF THE NORTHWEST AND THERE IS A GOOD CHANCE THAT  
GALE CONDITIONS COULD BEGIN TO DEVELOP THEN BUT AT THAT TIME WE ARE  
ANTICIPATING A TROPICAL DEPRESSION IF NOT TROPICAL STORM AND WITH  
THAT WARNINGS WILL LIKELY BE IN PLACE. IF THE SYSTEM GOES FURTHER  
EAST THEN WE WOULD LIKELY HAVE SMALL CRAFT ADVISORIES IN PLACE.  
CONDITIONS MAY NOT REALLY IMPROVE UNTIL LATE TUESDAY OR MORE SO  
WEDNESDAY AS THE SYSTEM WILL BE VERY SLOW TO MOVE. /CAB/  
 

 
   
AVIATION
 
CONVECTION ACROSS THE FORECAST AREA HAS REALLY  
DIMINISHED THANKS TO THE OUTFLOW BOUNDARIES THAT MOVED THROUGH THE  
REGION. THE ONE AREA WITH ACTIVITY NOT TOO FAR AWAY IS MCB AND  
AROUND PQL AS WELL. EXPECT MVFR TO VFR CONDITIONS TO PREVAIL  
THROUGH THE OVERNIGHT HOURS. THERE COULD BE SOME EARLY MORNING  
PATCHY FOG THAT SHOULD QUICK DISSIPATE AFTER SUNRISE. EXPECT VFR  
CONDITIONS AND AFTERNOON SHOWERS TO PREVAIL ONCE AGAIN FOR  
WEDNESDAY. 13/MH  
 

 
   
DECISION SUPPORT
 
 
DSS CODE: GREEN.  
DEPLOYED: NONE.  
ACTIVATION: NONE.  
ACTIVITIES: NONE.  
 
DECISION SUPPORT SERVICES (DSS) CODE LEGEND  
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION.  
BLUE = LONG-FUSED WATCH, WARNING, OR ADVISORY IN EFFECT OR  
HIGH VISIBILITY EVENT; MARGINAL RISK SEVERE OR EXCESSIVE RAIN.  
YELLOW = HEIGHTENED IMPACTS WITH SHORT-FUSED WATCH, WARNING OR  
ADVISORY ISSUANCES; RADAR SUPPORT FOR SLIGHT RISK SEVERE OR  
EXCESSIVE RAIN.  
ORANGE = HIGH IMPACTS; ENHANCED RISK SEVERE; NEARBY TROPICAL EVENTS;  
HAZMAT OR OTHER LARGE EPISODES.  
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK OF SEVERE AND/OR  
EXCESSIVE RAIN, OR DIRECT TROPICAL THREATS; EVENTS OF  
NATIONAL SIGNIFICANCE.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
MCB 69 85 68 86 / 50 50 30 60  
BTR 72 88 71 88 / 40 60 30 60  
ASD 71 89 71 86 / 30 60 40 70  
MSY 74 88 74 87 / 20 70 30 60  
GPT 73 87 73 85 / 30 60 50 70  
PQL 70 86 70 85 / 30 60 50 70  
 

 
   
LIX WATCHES/WARNINGS/ADVISORIES
 
 
LA...NONE.  
GM...NONE.  
MS...NONE.  
GM...NONE.  

 
 

 
 
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