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

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FXUS64 KLIX 291307
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
807 AM CDT MON SEP 29 2014

...SOUNDING DISCUSSION...

DESPITE DRIER AIR WORKING INTO THE UPPER LEVELS /ABOVE
450MB/ SINCE LAST EVENING/S BALLOON...ATMOSPHERIC PROFILE REMAINS
SATURATED WITH PRECIPITABLE WATER VALUE AROUND 2.2 INCHES. MLCAPE
WAS CALCULATED AROUND 250 J/KG SO INSTABILITY IS LIMITED TODAY
MORE SO THAN YESTERDAY. THERE ARE NO TEMPERATURE INVERSIONS ON THE
PROFILE WITH TEMPERATURES GENERALLY A DEGREE OR TWO HIGHER OR
LOWER AT ANY GIVEN LEVEL SINCE YESTERDAY AT THIS TIME.

WINDS ARE PRIMARILY FROM THE EAST OR NORTHEAST FROM THE SURFACE TO
12000 FEET...THEN LIGHT AND VARIABLE UNTIL 23500 FEET WHERE WINDS
BECOME FROM THE NORTHWEST THROUGH THE REMAINDER OF THE PROFILE. A
PEAK WIND OF 42 KNOTS WAS LOCATED AT 36000 FEET.

12Z BALLOON INFO: BALLOON FLIGHT LASTED 88 MINUTES AND REACHED A
HEIGHT OF 16 MILES ABOVE THE GROUND BURSTING OVER LAKE BORGNE 22
MILES DOWNRANGE.

ANSORGE

&&

.PREV DISCUSSION... /ISSUED 405 AM CDT MON SEP 29 2014/

SYNOPSIS...DEEP MID LVL LOW CURRENTLY LOCATED OVER THE SIERRA
NEVADA WITH THE DISTURBANCE THAT BROUGHT THE RAIN OVER OUR REGION
NOW IN PHASE WITH A TROUGH MOVING INTO THE OH/TN VALLEYS AND TWRDS
THE APPALACHIANS. A RIDGE IS BETWEEN THE CLOSED LOW IN THE WEST AND
TROUGH IN THE EAST. AT THE SFC...A STATIONARY BNDRY IS DRAPED ACROSS
THE NRN GULF WITH BROAD HIGH PRESSURE DOMINATING MUCH OF THE ERN
CONUS. A COLD FRONT IS LOCATED OVER THE NRN GRT LAKES AND DRAPED
ACROSS THE NRN PLAINS AND INTO THE ROCKIES. THIS FRONT WILL
EVENTUALLY BECOME THE FRONT THAT MOVES THROUGH AT THE END OF THE
WEEK. /CAB/

SHORT TERM...LINGERING SHRA ALONG AND JUST OFF THE MS COAST AND WEST
INTO SELA HAVE CONTINUED THROUGH MUCH OF THE NIGHT AND WILL LIKELY
DO SO TILL SUNRISE WHILE SLOWLY DRIFTING SOUTH. HUMID NIGHT OUT
THERE WITH TEMPS ONLY IN THE LOWER TO MID 70S WHICH IS RIGHT AROUND
THE CURRENT DEWPOINTS.

OVER THE NEXT 3 DAYS THE PATTERN WILL BEGIN TO SHIFT SOME BUT OUR
SENSIBLE WEATHER WILL BE FAIRLY SIMILAR EACH DAY. OUR DISTURBANCE
HAS CONTINUED TO MOVE EAST ACROSS THE NRN GULF AND RIDGING WILL MOVE
IN PLACE TODAY AND TOMORROW. THAT SAID HGHTS DON/T REALLY INCREASE
WITH H5 HGHTS B/T 584-586DM THROUGH WED. IN ADDITION WE WILL NOT
SEE MUCH IN THE WAY(IF ANY) OF DRYING OUT. PWS WILL REMAIN ABV 1.5
INCHES OVER THE SAME TIME FRAME. LAST AS PREVIOUS FCSTER
MENTIONED...THAT BNDRY DRAPED ACROSS THE NRN GULF IS EXPECTED TO
REMAIN CLOSE TO THE COAST TODAY BEFORE WASHING OUT TONIGHT. THIS
WILL ACT AS A FOCUS FOR ADDITIONAL SHRA ACTIVITY TODAY ALONG WITH
A LITTLE OVERRUNNING. INSTABILITY WILL BE QUITE LIMITED TODAY AND
TONIGHT SO HAVE OPTED OUT OF INCLUDING THUNDER IN THE FCST.

BY TUE THE CLOSED LOW THAT IS CURRENTLY OVER THE SIERRA NEVADA
WILL HAVE LIFTED OUT ACROSS THE CONTINENTAL DIVIDE LEAVING A L/W
TROUGH OVER THE WRN CONUS. THIS WILL QUICKLY PUSH THE RIDGE OVER
THE CNTRL CONUS EAST AND THUS FLATTENING IT OUT OVER THE LOWER MS
VALLEY. THIS WILL NOT PROVIDE MUCH SUBSIDENCE IN THE MID LVLS NOW
WHILE THERE WILL BE SOME LL CONVERGENCE IN PLACE ACROSS THE
REGION. COMBINE THAT WITH VERY WEAK ISENTROPIC LIFT AROUND THE
305K LVL AND THIS SHOULD AID IN ISLTD TO SCT CONVECTION AS WE HEAT
UP. THERE WILL BE A LITTLE MORE INSTABILITY IN PLACE SO WILL
INCLUDE THUNDER IN THE FCST FOR TUE.

BY WED WHATEVER IS LEFT OF THE RIDGE OVER THE REGION WILL SHIFT
EAST AND WE WILL SLOWLY BEGIN TO MOVE UNDER SW FLOW. A WEAK
IMPULSE MAY MOVE THROUGH DURING THIS TIME AND PROVIDE ADDITIONAL
SCT SHRA AND TSRA DURING THE DAY. /CAB/

LONG TERM...OVERALL THE MEDIUM RANGE MDLS ARE IN RATHER GOOD
AGREEMENT. THE MAIN DIFFERENCES THROUGH NEXT WEEKEND APPEAR TO BE
SOME SMALL TIMING DIFFERENCES WITH THE ERN CONUS L/W TROUGH AND THE
AMPLITUDE OF THE PATTERN OVER THE CONUS. THE MDLS CONTINUE TO TREND
FASTER WITH THE ECMWF BEGIN THE FASTER MDL. THE ECMWF IS ALSO MORE
AMPLIFIED. THAT SAID THE GFS TRENDED FASTER AS WELL AND WITH THAT
HAVE USED A BLEND APPROACH WITH A HIGHER WEIGHT TWRDS THE ECMWF FOR
FRI AND THIS WEEKEND GIVEN THE TRENDS.

THU WILL BE A WETTER DAY. AS THE L/W TROUGH STARTS WORKING EAST SW
FLOW WILL INCREASE OVER THE AREA. MOISTURE WILL BE ON THE RISE AS
WELL. ONCE THE L/W TROUGH AXIS STARTS TO PUSH EAST OF THE ROCKIES
CYCLOGENESIS WILL OCCUR OVER THE CNTRL PLAINS. THIS LOW WILL RACE
NE THU NIGHT AS THE L/W TROUGH MOVES IN THE PLAINS AND DIGS. THIS
WILL FINALLY GET THE COLD FRONT THAT IS SITTING OVER THE NRN
PLAINS TO SURGE SOUTH AND BY LATE THU NIGHT WILL BE ON OUR
DOORSTEP. AHEAD OF THIS FRONT LOOK FOR SHRA AND EMBEDDED TSRA TO
INCREASE.

FRI...STILL LOOKING HIGHLY LIKELY THAT OUR FIRST TRUE COLD FRONT
WILL MOVE THROUGH AT THE END OF THE WORK WEEK PROVIDING WHAT WILL
FEEL LIKE A FALL WEEKEND. MDLS ARE INDICATING A FASTER FRONTAL
PASSAGE WITH THE FRONT POSSIBLY IN THE GULF FRI AFTN. SHRA AND
TSRA ARE LIKELY WITH THE FRONT BUT WILL QUICKLY COME TO AN END
AFTER FRONTAL PASSAGE WITH SOME LOCATIONS IN OUR NW POSSIBLY RAIN
FREE NO LATER THAN 15Z. NOT ANTICIPATING ORGANIZED SVR WEATHER BUT
WITH MID LVL FLOW APPROACHING 40 KTS...SOME INSTABILITY TO WORK
WITH...ALONG WITH RATHER STRONG FORCING THANKS TO THE FRONT AND
TROUGH AXIS...CANT RULE OUT A FEW STRONG AND POSSIBLY SVR STORMS
ALONG AND JUST AHEAD OF THE FRONT FRI.

AFTER THE COLD FRONT MOVES THROUGH MUCH DRIER AND COOLER AIR WILL
MOVE IN. DEWPOINTS ARE NOW BEING ADVERTISED BY THE RAW MDL TO DROP
INTO THE LOWER 40S AT LEAST. THE COLDEST MORNING LOOKS TO BE SUN AS
THE SFC HIGH SITS RIGHT OVER THE REGION PROVIDING THE BEST RAD
COOLING CONDITIONS. CURRENTLY HAVE LOWER TO MID 50S IN THE FCST FOR
AREAS ALONG AND NORTH OF THE 10/12 CORRIDOR. THE SOUTHSHORE COULD
SEE LOWER 60S. /CAB/

AVIATION...

MVFR AND IFR CONDITIONS EARLY THIS MORNING DUE PRIMARILY TO LOW
CEILINGS WILL ONLY GRADUALLY IMPROVE THROUGH THE MORNING HOURS AFTER
SUNRISE. IN THE AFTERNOON...VFR CONDITIONS WILL GENERALLY PREVAIL.
SCATTERED SHOWERS WILL REMAIN POSSIBLE AT ALL OF THE TERMINALS
TODAY. MAINLY VFR CONDITIONS ARE EXPECTED TONIGHT AND EARLY TUESDAY
MORNING...ALTHOUGH PATCHY FOG MAY RESULT IN OCCASIONAL MVFR VSBYS
AFTER 06Z. 11

MARINE...

GENERALLY LIGHT EAST TO NORTHEAST...BUT OCCASIONALLY VARIABLE...
WINDS WILL PREVAIL TODAY AND TONIGHT ACROSS THE COASTAL
WATERS...ALTHOUGH SOMEWHAT HIGHER WINDS WILL BE POSSIBLE ACROSS
AREAS TO THE EAST OF THE MISSISSIPPI RIVER. ONSHORE FLOW WILL BEGIN
TO DEVELOP LATE TUESDAY INTO WEDNESDAY...AND WILL INCREASE WEDNESDAY
NIGHT INTO THURSDAY AS THE PRESSURE GRADIENT INCREASES BETWEEN A
DEPARTING HIGH OVER THE EASTERN SEABOARD AND DEVELOPING LOW IN THE
PLAINS. A STRONG COLD FRONT WILL PUSH ACROSS THE COASTAL WATERS
FRIDAY AND FRIDAY NIGHT. 11

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  85  69  86  70 /  40  30  30  10
BTR  86  71  87  71 /  40  30  40  20
ASD  85  69  86  70 /  40  40  30  20
MSY  85  73  86  73 /  40  40  30  20
GPT  85  70  85  71 /  50  40  30  20
PQL  85  68  85  68 /  50  40  30  20

&&

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

$$







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