Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
600
FXUS64 KLIX 130821
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
321 AM CDT MON APR 13 2015

.SHORT TERM...
NEXT WEATHER PLAYER IS MCV MOVING OUT OF DEEP SOUTH TX INTO THE
GULF OF MEXICO TONIGHT. NO REAL SIGNS OF WEAKENING PER WSR88D AND
SATELLITE IMAGERY. MARGINAL RISK OF SEVERE WEATHER ASSOCIATED WITH
THE MCV IN THE FORM OF HIGH WINDS...FREQUENT LIGHTNING...AND
TORRENTIAL RAIN ASSOCIATED WITH THE STRONGER STORMS. LOOKING AT
THE 00Z SOUNDING ALSO INDICATES INSTABILITY IN THE POST WARM FRONT
ENVIRONMENT WITH PARCEL CAPE VALUES OF 900 TO 1000 J/KG AND BULK
SHEAR VALUES OF 22 M2/S2. PW MEASURED AT 1.94 INCHES INDICATES
RAIN THAT DOES FALL WILL BE QUITE EFFICIENT IN NATURE. HELICITY
IMPRESSIVE AT OVER 200 M2/S2. NOW THERE COULD BE SOME MODIFICATION
FROM 00Z TO THIS MORNING...WE WILL SEE ONCE WE LAUNCH THE 12Z
RADIOSONDE AND ADJUST IF NEEDED. EVEN THOUGH NOT WIDESPREAD...THERE
IS A NON- ZERO CHANCE OF A SOME WATERSPOUTS AND/OR BRIEF TORNADOES
ASSOCIATED WITH THE STRONGER STORMS AND ESPECIALLY WHEN THEY
INTERACT WITH MESOSCALE BOUNDARIES. I DID EXPAND AND EXTEND THE
FLASH FLOOD WATCH TO INCLUDE AREAS THAT RECEIVED HEAVY RAIN
YESTERDAY...IE THE MS GULF COAST WITH OVER 3 INCHES IN MANY AREAS
BETWEEN 00Z AND 06Z LAST NIGHT. ANY RAIN OVER THE WATCH AREA
BECOMES A PROBLEM AS ACCUMULATED RAINFALL TOTALS OVER THE LAST FEW
DAYS HAS LOWERED FFG VALUES TO AROUND 2 TO 2.5 INCHES PER HOUR
WHICH IS ATTAINABLE CONSIDERING THE THE CURRENT ENVIRONMENT.

HRRR TAKES THE MCV TO THE FORECAST AREA AROUND 13Z WITH SOME
SHRA DEVELOPING OUT AHEAD BEGINNING BETWEEN 8Z AND 9Z. RADAR
ALREADY SUPPORTING THIS FORECAST. THE MAIN MCV WILL REACH KBTR
AROUND 8AM...LAKE PONTCHARTRAIN BY 11AM/NOON... AND THE MS GULF
COAST AROUND 1 TO 2PM. /KEG/

.LONG TERM...
WEATHER MODELS ARE ALL A LITTLE OFF IN TIMING AND COVERAGE OF
RAIN BUT WE CAN TAKE AWAY AT LEAST A VERY EL NINOESK WET PATTERN
CONTINUING FOR MUCH OF THE WEEK. ECMWF LOW AT 06Z LAST NIGHT WAS
PLOTTED CLOSE TO SATELLITE PER THE 3.9U CHANNEL OBSERVATION. CLOSED
LOW WAS IN SW NM WITH PLENTY OF FORCING AND IMPULSES OUT AHEAD.
DIFFLUENT FLOW ALOFT ALSO AIDING IN CURRENT AND FUTURE SHRA/TSTM
ACTIVITY OVER OUR AREA.

CURRENT LOW PROGGED OVER THE TX PANHANDLE AT 06Z TUE AS YET
ANOTHER TROUGH DIGS IN SOUTH OVER THE ROCKIES LATE IN THE WEEK.
A LOW CLOSES OFF AT THE BASE OF THE TROUGH OVER THE 4 CORNERS
AROUND 06Z THU. MODELS INDICATING THIS SETTING UP SIMILAR TO THE
CURRENT SITUATION WITH IMPULSES EJECTING EAST AND A DIFFLUENT
UPPER PATTERN. THIS SPELLS ADDITIONAL SHRA/TSTM CHANCES INTO
THU/FRI/SAT HOWEVER CONFIDENCE NOT QUITE AS HIGH ESPECIALLY
GETTING INTO NEXT WEEKEND. BY 18Z SUN THE CLOSED LOW HOVERS AROUND
WESTERN KS AND SHOULD BE PUSHING RAIN CHANCES EASTWARD WITH IT.
INTERESTING TO NOTE YET ANOTHER TROUGH AND ASSOCIATED CLOSED LOW
DIVES SOUTH OFF THE CA COAST PER THE GFS AND ECMWF AT THE 200 TO
240 HOUR MARK. LOTS OF UNCERTAINTY WITH THIS BUT DOES CONTINUE THE
CURRENT TREND OF A VERY ACTIVE SOUTHERN STREAM WITH SYSTEM LINED
UP FOR THE NEXT WEEK AND POSSIBLY BEYOND. /KEG/

&&
.AVIATION...JUST ABOUT ALL OF THE TERMINALS ARE DEALING WITH SOME
LOW CIGS AND/OR LOWERED VSBYS. CIGS ARE EVEN AS LOW AS 100-200 FT.
THIS WILL CONTINUE THROUGH THE EARLY MORNING HRS BUT BOTH CIGS AND
VSBYS SHOULD BEGIN TO IMPROVE AFTER 13Z. THAT SAID IT IS HIGHLY
LIKELY THAT MVFR CIGS WILL PLAGUE MOST TERMINALS THROUGH THE DAY. AS
FOR CONVECTION WE ARE IN A LULL FOR THE MOST PART UNTIL ABOUT
13/14Z. AT THAT TIME SCT SHRA WILL LIKELY START TO BREAK OUT AGAIN
AHEAD OF WHAT SHOULD BE A STRONG LINE OF SHRA AND TSRA. THIS LINE
MOVED OFF THE SRN AND CNTRL TX COAST AROUND 7Z AND WILL CONTINUE TO
WORK TO THE NE THROUGH THE MORNING. IT SHOULD HOLD FOR THE MOST PART
REACHING THE CWA AROUND 14/15Z. /CAB/

&&

.MARINE...OUTSIDE OF CONVECTION WINDS SHOULD GENERALLY BE OUT OF THE
SE AND S THROUGH THE NEXT FEW DAYS. WINDS NEVER REALLY SEEM TO GET
VERY STRONG SO ONLY LOOKING FOR MODERATE ONSHORE AT TIMES...IN THE
10-15KT RANGE. B/C CONCERN WOULD BE IN THE NEXT 12 HRS WITH
CONVECTION CURRENTLY MOVING OVER THE NW GULF. THIS LINE OF STORMS IS
STRONG AND IF IT HOLDS WILL LIKELY PROMPT MARINE WARNINGS AS IT
MOVES INTO AND THROUGH THE COASTAL WATERS. /CAB/

&&

.DECISION SUPPORT...
DSS CODE...BLUE.
DEPLOYED...METS WRAPPING UP AT AVONDALE AND NEW ORLEANS COMMAND
CENTER ACTIVATION...YES.
ACTIVITIES...FLASH FLOOD WATCH
             FRENCH QUARTER FEST PUBLIC SAFETY SUPPORT
             GRAND PRIX OF LOUISIANA PUBLIC SAFETY SUPPORT

DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN  = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE   = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
         VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
         WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
         TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED    = FULL ENGAGEMENT FOR MODERATE TONIGHT RISK SVR
         AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
         SIGNIFICANCE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  73  67  74  65 / 100  50  80  60
BTR  75  68  75  66 / 100  50  80  50
ASD  75  69  77  67 / 100  50  80  50
MSY  76  70  76  68 / 100  50  70  50
GPT  72  71  74  70 / 100  40  70  50
PQL  75  71  78  70 / 100  40  70  50

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR LAZ040-046>050-
     056>070-072.

GM...NONE.
MS...FLASH FLOOD WATCH THROUGH TUESDAY EVENING FOR MSZ080>082.

GM...NONE.
&&

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.