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

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667
FXUS64 KLIX 110834
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
334 AM CDT THU SEP 11 2014

.SHORT TERM...DEEPER MOISTURE IS ALREADY PUSHING IN AND THIS IS
EVIDENT WITH ISLTD SHRA ALREADY DEVELOPING OVER COASTAL AREAS. OTHER
THAN THAT THINGS HAVE BEEN FAIRLY QUIET WITH TEMPS ONLY DOWN INTO
THE MID 70S TO LOWER 80S AT 7Z.

OVER THE NEXT 3 DAYS LOOK FOR RAIN TO BECOME MORE
FAVORABLE...ESPECIALLY FRI AND SAT AS A FRONT SLIDES INTO AND STALLS
OVER THE REGION. AS MENTIONED EARLIER DEEPER MOISTURE IS ALREADY
MOVING IN AND WILL CONTINUE TO DO SO AHEAD OF THE APPROACHING FRONT
TODAY. THE NEGATIVE ISSUE THAT WE HAVE HAD WITH RESPECT TO
CONVECTION THE LAST FEW DAYS HAS BEEN THE RIDGE SITTING OVERHEAD
WITH FAIRLY WARM MID LVL TEMPS BUT THIS APPEARS TO BE CHANGING
TODAY. WITH THE ADDITION OF MORE MOISTURE AND THE STRONG S/W
DROPPING SOUTH ACROSS THE BIG SKY/HIGH PLAINS REGION MID LVL TEMPS
WILL COOL A TAD. NOW H5 TEMPS WILL ONLY DROP FROM -4 TO -6C BUT THIS
SMALL CHANGE WILL HAVE A BIG DIFFERENCE FROM VERY ISLTD CONVECTION
LATE IN THE AFTN TO SCT CONVECTION LIKELY BEGINNING AROUND MIDDAY
ALONG THE COAST. FURTHER INLAND CONVECTION WILL LIKELY STILL BE
ISLTD BUT THIS WILL CHANGE ON FRI.

THU NIGHT A BROAD L/W TROUGH WILL DOMINATE MUCH OF THE NRN HALF OF
THE CONUS WITH THE AFOREMENTIONED HIGH PLAINS S/W DROPPING SE. THIS
IS SENDING A RATHER COOL AIRMASS SOUTH THROUGH THE PLAINS AND WILL
DRIVE A COLD FRONT INTO THE LOWER MS VALLEY FRI. ABUNDANT MOISTURE
WILL POOL ALONG AND AHEAD OF THIS FRONT. COMBINE THAT WITH A
WEAKENING RIDGE...DEVELOPING SEABREEZE AND MAYBE EVEN THE RRQ OF A
WEAK UPPER LVL JET STREAK AND WE COULD SEE SCT TO NUM SHRA AND TSRA
FRI AFTN AND INTO THE EARLY EVNG HRS FRI. STORM MOTION WILL BE
FAIRLY SLOW AND THERE IS EVEN THE POSSIBILITY OF TRAINING SO SOME
HEAVY RAIN IS NOT OUT OF THE QUESTION.

HEADING INTO THE WEEKEND THE FRONT WILL STALL OVER THE REGION
PROVIDING A FOCUS FOR CONVECTION. WILL CONTINUE TO SHOW SCT TO
POSSIBLY NUM STORMS ON SAT BUT THERE ARE A FEW NEGATIVES WHICH COULD
REALLY DROP THE STORM POTENTIAL SAT. FIRST THE MID LVL RIDGE BEGINS
TO REBUILD OVER THE REGION AND SECOND IF THE FRONT IS A LITTLE
STRONGER THAN ANTICIPATED OR GETS ADDED INFLUENCE FROM OUTFLOW/COLD
POOLING AND SURGES DEEPER INTO THE GULF THE AIRMASS MAY BECOME
MODIFIED ENOUGH LEADING TO LESS CONVECTION. AGAIN NOT ANTICIPATING
THE FRONT TO PUSH INTO THE GULF SO WILL HOLD ONTO 50% POPS. MOVING
INTO SUN RAIN CHANCES DROP SOME WITH THE HIGHER POPS CONFINED CLOSER
TO THE COAST. THERE IS SOME QUESTION ABOUT THAT THOUGH THAT COULD
LEAD TO HIGHER RAIN CHANCES. HEADING INTO SAT NIGHT AND SUN THERE IS
THE POTENTIAL FOR A WEAK TROPICAL WAVE COMING ACROSS FL AND THROUGH
THE GULF WHICH COULD SERVE TO BRING AN EVEN GREATER FOCUS FOR
CONVECTION SUN. HOWEVER...LATEST MDL RUNS(CANADIAN IS THE EXCEPTION)
ACTUALLY SHOW THIS WAVE PUSHING MORE WSWRD AND THUS KEEPING THE
DEEPER MOISTURE SOUTH OF THE AREA. AS PREV FCSTER MENTIONED THE KEY
AND MAIN QUESTION FROM AN IMPACT STANDPOINT WILL BE WHETHER THE
FRONT AND THIS WAVE INTERACT/INTERSECT WITH EACH OTHER. IF THE
CURRENT MDL RUNS ARE CORRECT AND THIS WAVE STAYS TO THE SOUTH THEN
THE IMPACTS WILL BE MINIMAL BUT IF THE FRONT STALLS OVER THE REGION
AND THE WAVE IS CLOSER TO THE COAST OR EVEN INLAND SOMEWHAT THEN
VERY HEAVY LIKELY FLOODING RAIN COULD BECOME A ISSUE. WE WILL
CONTINUE TO MONITOR THIS POTENTIAL. /CAB/

.LONG TERM...MEDIUM RANGE MDLS ARE IN DECENT AGREEMENT. BOTH THE GFS
AND ECMWF SHOW THE RIDGE TEMPORARILY OVER THE REGION BEFORE IT
BREAKS DOWN AND ANOTHER COLD FRONT ON THE HEELS OF OUR FIRST. THE
PATTERN BECOMES MORE AMPLIFIED THROUGH THE EXTENDED PORTION OF THE
FCST WITH WHAT SEEMS TO BE THE THEME OF THE PAST YEAR...EAST
COAST/CONUS L/W TROUGH AND A RIDGE OVER THE CONTINENTAL DIVIDE. THIS
WILL DROP THAT SECOND COLD FRONT SOUTH INTO THE REGION AROUND MID
WEEK AND THUS CONTINUED ABV NORMAL RAIN CHANCES. /CAB/

&&

.AVIATION...VFR CONDITIONS TO PREVAIL THROUGH AT LEAST 09Z. SOME
PATCHY RADIATIONAL FOG MAY DEVELOP AT KMCB TOWARDS DAYBREAK THURSDAY
THAT MAY BRING BRIEF IFR CIGS/VSBY BUT MOST OTHER LOCATIONS SHOULD
REMAIN VFR OVERNIGHT. RADAR SHOWS SHOWERS ALREADY DEVELOPING AND
MOVING INLAND ALONG THE COASTAL AREAS. WILL HAVE VCSH FOR HUM TO GPT
BY THE START OF THE TAF PERIOD. MORE INLAND LOCATIONS WILL BE A FEW
HOURS BEHIND THAT AS CONVECTION BEGINS TO SPREAD NORTH. WITH
COVERAGE OF AROUND 40 PCT...WILL HAVE VCTS NOTATION AT ALL
LOCATIONS. GUST POTENTIAL IS AROUND 20 TO 30 KT RANGE. VFR TO RETURN
FOR THE EVENING AND MOST HOURS IN THE NIGHT. /MEFFER/

&&

.MARINE...BERMUDA RIDGE IS STILL STRONG IN THE WESTERN ATLANTIC AND
EXTENDS WELL INTO THE GULF OF MEXICO. GENERALLY LIGHT WINDS OF 10
KNOTS OR LESS AND 1 FOOT SEAS EXPECTED TODAY AND TOMORROW WITH THIS
PATTERN IN PLACE.  MODELS INDICATING THAT A COLD FRONT WILL PUSH
INTO THE COASTAL WATERS FRIDAY NIGHT INTO SATURDAY MORNING. IT WILL
BE WEAKENING AS IT DOES SO...MORESO LIKE A BACKDOOR FRONT AS THE
UPPER RIDGE TO THE NORTH THAT BROUGHT THE FRONT IN WILL ALREADY BE
LIFTING AWAY. THUS WINDS WILL BE MORE OF A NORTHEAST AND EAST
DIRECTION ON SATURDAY. WINDS WILL QUICKLY SHIFT BACK TO SOUTHEAST AS
THE BOUNDARY DIMINISHES. SPEEDS WILL BE 10 TO 15 KNOT WITH SEAS UP
TO 3 FEET IN THE OUTER WATERS THIS WEEKEND. /MEFFER/

&&

.DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY 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 TO HIGH RISK SVR
         AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
         SIGNIFICANCE.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  90  73  89  71 /  40  30  60  40
BTR  92  74  90  72 /  40  30  60  40
ASD  90  74  90  72 /  40  30  60  40
MSY  91  77  90  76 /  40  30  60  40
GPT  89  75  89  74 /  40  30  50  40
PQL  90  72  90  71 /  40  30  50  30

&&

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

$$

SHORT/LONG TERM: CAB
AVIATION/MARINE: MEFFER





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