Area Forecast Discussion


439 
FXUS64 KLIX 130852
AFDLIX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
352 AM CDT TUE AUG 13 2013
.SYNOPSIS...RIDGE OVER THE N-CNTRL GULF WEAKENING AND RIDGE IS NOW 
BUILDING OVER THE DESERT SW/4 CORNERS. WEAK NW FLOW STARTING TO SET 
UP OVER THE LOWER MS VALLEY. LARGE POLAR LOW IS OVER ONTARIO WITH 
THE L/W TROUGH SLOWLY DIGGING AND THE TROUGH AXIS RUNNING THROUGH 
LAKE MICHIGAN AND JUST EAST OF THE MID MS VALLEY. AT THE 
SFC...STALLED FRONT STILL REMAINS WELL OFF TO THE NORTH DRAPED FROM 
NRN OK...ALONG THE MO/AR BORDER AND INTO THE OHIO VALLEY. RADAR WISE 
A FEW STORMS HAVE BEGUN TO DEVELOP OVER THE COASTAL WATERS
.SHORT TERM...SOUNDING LIKE A BROKEN RECORD HERE BUT IT WAS ONCE 
AGAIN A MOSTLY QUIET NIGHT. WE ARE STARTING TO GET A LITTLE 
DEVELOPMENT OVER THE MARINE ZONES A TAD FASTER THAN PREV NIGHTS AND 
SOME OF THIS ACTIVITY HAS LIGHTNING WITH IT. EXPECT COVERAGE TO 
SLOWLY INCREASE ACROSS THE COASTS THROUGH THE MORNING. 
TODAY SCT TO NUM CONVECTION IS EXPECTED ONCE AGAIN. RIDGE HAS ALREADY 
BROKEN DOWN ACROSS THE GULF AND L/W TROUGH IS SLOWLY DIGGING OVER 
THE ERN CONUS. THIS IS CAUSING THE HGHTS TO LOWER EVER SO SLOWLY 
OVER THE LOWER MS VALLEY AND WITH ABUNDANT MOISTURE TO WORK 
CONVECTION WILL GET GOING ONCE WE START HEATING UP. CONVECTION WILL 
LIKELY BE MORE DIURNALLY DRIVEN INITIALLY AND THEN DRIVEN BY 
BOUNDARY/OUTFLOW INTERACTIONS. THE REASON FOR THIS IS THERE DOESNT 
APPEAR TO BE ANY NOTICEABLE DISTURBANCE EMBEDDED IN THE NW FLOW 
COMING DOWN INTO OUR AREA UNTIL THE OVERNIGHT HRS AND TOMORROW. A 
FEW STRONG TO SEVERE STORMS CANT BE RULED OUT AND IF THEY DEVELOP IT 
WILL LIKELY BE OVER THE NRN HALF OF THE CWA. 
TONIGHT AND TOMORROW...CONVECTION WILL INITIALLY DIE DOWN DURING THE 
EVNG HRS ONCE WE LOSE THE DAYTIME HEATING BUT AFTER MIDNIGHT 
CONVECTION MAY START TO RE-FIRE IF NOT MOVE IN FROM THE NW. A STRONG 
IMPULSE ASSOCIATED WITH CONVECTION IN THE SRN/CNTRL PLAINS WILL WORK 
SE INTO THE LOWER MS VALLEY TODAY AND INTO OUR AREA TONIGHT AND 
THERE SHOULD BE SUFFICIENT CONVECTION ASSOCIATED WITH IT. THIS 
IMPULSE WILL SLOWLY MOVE ACROSS THE CWA DURING THE DAY WED AND IT 
WILL HELP TO DIG THE ERN CONUS L/W TROUGH ALL THE WAY INTO THE GULF. 
THIS WILL ALSO DRIVE THAT STALLED BNDRY TO OUR NORTH TO THE SOUTH 
AND INTO THE CWA WED. THE COMBINATION OF MID/UPPER LVL SUPPORT...LL 
FORCING...AND PWS ATA 2.25" SUGGEST NUM TO EVEN WIDESPREAD SHRA AND 
TSRA...SOME WHICH COULD BE HEAVY. HEAVY RAIN IS A CONCERN AS THIS 
FRONT HAS BEEN ASSOCIATED WITH HEAVY RAIN IN MULTIPLE AREAS. K INDEX 
VALUES WILL BE IN THE UPPER 30S...PWS WILL BE 130% OF NORMAL AND 
COULD BE JUST UNDER 2.5". THE H85 THETA E RIDGE WILL BE DRAPED 
ACROSS THE CWA ALL DAY. IN ADDITION THE MDLS ARE SHOWING THAT WE 
COULD HAVE SOME DIVERGENCE ALOFT TO WORK WITH AS WELL. WILL KEEP THE 
MENTION OF HEAVY RAIN IN THE GRIDS/ZONES AND SLIGHTLY BEEF UP THE 
WORDING IN THE HWO W/RESPECT TO FLOODING ON WED.
WED NIGHT THROUGH FRI...THE COLD FRONT WILL HAVE A PRETTY GOOD PUSH AND 
COULD GET ALL THE WAY INTO THE GULF BY THURSDAY MORNING. YES THAT IS 
CORRECT A COLD FRONT INTO THE GULF ON AUG 15TH AND THIS WILL DO A 
FEW THINGS. FIRST OFF IT COULD ALLOW THE CWA TO BEGIN TO DRY OUT 
OVER THE NRN PORTIONS OF THE CWA A LITTLE FASTER THAN EXPECTED WITH 
ONLY ISLTD TO SCT CONVECTION ON FRI...BEST CHANCE FOR RAIN WILL BE 
THE SERN HALF/3RD OF THE CWA ON FRI. IT COULD ALSO PROVIDE VERY 
PLEASANT CONDITIONS FOR AUG. THE MDLS ARE INDICATING DEWPOINTS 
DROPPING SIGNIFICANTLY ACROSS THE NWRN HALF OF THE CWA THU AND FRI 
WITH THE LATEST MEX GUI SUGGESTING LOWS IN THE LOWER 60S ACROSS SWRN 
MS. 
.LONG TERM...WITH THE EXCEPTION OF THE TROPICAL WAVE THE MEDIUM 
RANGE MDLS ARE IN DECENT AGREEMENT. BOTH THE GFS AND ECMWF SHOW THE 
FRONT STALLED OVER THE NRN GULF THE L/W TROUGH REMAINING OVER THE 
AREA THROUGH THE WEEKEND. OVERALL LITTLE DEVIATION MADE FROM LATEST 
MEX. 
THIS WEEKEND WILL LIKELY BE A LITTLE MORE QUIET WITH ONLY ISLTD TO 
SCT CONVECTION...MOST OF THE RAIN WILL FOCUS ACROSS THE SERN HALF OF 
THE CWA. THIS IS DUE TO THE BNDRY GETTING INTO THE GULF AND THE L/W 
TROUGH AXIS SETTING UP RIGHT OVER THE REGION WITH THE MOISTURE BEING 
SHUNTED OFF TO THE EAST. AFTER HIGHS WILL BE NEAR NORMAL BUT MORNING 
LOWS ON SAT COULD BE A TAD BELOW NORMAL ESPECIALLY ACROSS OUR NW. 
NOW WE HAVE BEEN KEEPING AN EYE ON THIS WAVE IN THE CNTRL CARIBBEAN 
AND LATEST GFS CONTINUES TO HOLD ONTO A SFC REFLECTION...ALBEIT 
WEAK...DRIFTING TO THE N AND THEN RE-CURVING TO THE NORTH AND NE 
WHILE IN THE ERN GULF. WITH A STALLED BNDRY AND BEING JUST 
DOWNSTREAM OF THE TROUGH AXIS IT MERGES WITH A WEAK WAVE ALONG THE 
STALLED FRONT AND TRIES TO SPIN UP A SFC LOW...THIS IS NOT 
COMPLETELY TROPICAL IN NATURE BUT IT IS SOMETHING. GOOD NEWS IS IT 
LOOKS LIKE IF THAT HAPPENS IT WILL BE EAST OF OUR AREA. AS FOR THE 
ECMWF IT CONTINUES TO NOT LIKE THE SYSTEM AND SHOWS AN OPEN WAVE 
MOVING INTO THE YUCATAN. GIVEN HOW WEAK THE SYSTEM IS AND HOW FAR 
SOUTH IT CURRENTLY IS THE ECMWF MAKES MORE SINCE. NOW WITH THAT ALL 
SAID GOOD THING FOR US IS BOTH OF THE MDLS STILL SHOWED MOSTLY THE 
SAME SENSIBLE WEATHER FOR OUR AREA AND THUS HAVE STUCK TO THE MEX 
GUI. ONE SMALL ISSUE IS THE GFS IS DRIER AND SLIGHTLY COOLER FOR OUR 
AREA AND THIS COULD BE AN INDIRECT IMPACT OF IT TRYING TO SPIN UP A 
LOW IN THE GULF. WE WILL CONTINUE TO WATCH AND SEE. /CAB/
&&
.AVIATION... THERE HAS BEEN LITTLE TO NO SHOWER ACTIVITY IN THE CWA 
UP UNTIL THE LAST HALF HOUR OR SO. A FEW SHOWERS HAVE BEGIN TO 
DEVELOP EAST OF THE CHANDELEUR SOUND. MESO MODELS INDICATE THIS 
ACTIVITY WILL EXPAND OVER COASTAL PARISHES AT THE IMMEDIATE COAST 
THROUGH SUNRISE AND THEN FURTHER INLAND POSSIBLY AFFECTING MSY AND 
HUM. THE REST OF THE TERMINALS COULD BE IMPACTED LATE MORNING 
THROUGH THE AFTERNOON AS CONVECTION INCREASES WITH DAYTIME HEATING. 
SHORT TERM VIS RESTRICTIONS ARE POSSIBLE AT A FEW SITES NEAR SUNRISE 
AS LIGHT FOG MAY DEVELOP AND PRODUCE MVFR VIS. WHILE MOSTLY ONLY 
HIGH CLOUDS ARE IN PLACE ATTM...MID LEVEL DECK WILL LOWER TODAY WITH 
NEAR MVFR/VFR HEIGHTS. WILL KEEP AFTERNOON TEMPO GROUPS FOR 
THUNDERSTORMS. /MEFFER/
&&
MARINE...WEAK SURFACE HIGH PRESSURE RIDGE LOCATED OVER THE CENTRAL 
GULF OF MEXICO WILL MAINTAIN MOSTLY LIGHTER WINDS THROUGH  WEDNESDAY 
...ALTHOUGH SOME OF THE EASTERN WATERS AND THE MISSISSIPPI SOUND  
MAY RISE A BIT SLIGHTLY ABOVE 10 KNOTS AT TIMES. AN UNSEASONABLY 
STRONG COLD FRONT WILL MOVE SOUTH TOWARDS THE CENTRAL GULF COAST 
LATE WEDNESDAY INTO THURSDAY MORNING AND WILL GRADUALLY SAG TO THE 
COAST BEFORE STALLING THROUGH THE WEEKEND. THIS WILL GENERALLY KEEP 
WINDS OFFSHORE TO SOUTHWEST AT AROUND 10 KNOTS UNTIL THE FRONT 
FINALLY DISSIPATES. /MEFFER/
&&
DECISION SUPPORT...
DSS CODE...BLUE. 
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  72  87  68 /  70  50  80  30 
BTR  92  75  90  72 /  50  40  80  40 
ASD  91  75  87  71 /  60  40  80  40 
MSY  91  77  88  75 /  50  30  80  50 
GPT  90  75  87  72 /  60  40  80  40 
PQL  92  75  89  70 /  60  40  70  40 
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
SHORT/LONG TERM: CAB
MARINE/AVIATION: MEFFER