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

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632
FXUS64 KLIX 010854
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
354 AM CDT WED OCT 1 2014

.SHORT TERM...IT WAS A MOSTLY QUIET DAY YESTERDAY A FEW SHRA BROKE
OUT BUT OVERALL IT WAS DRY. THINGS HAVE REMAINED QUIET OVERNIGHT
WITH TEMPS GENERALLY RANGING FROM THE LOWER TO MID 70S BY 7Z.

RAIN LOOKS TO RETURN TODAY AND THERE IS SOME INDICATION THAT THERE
MAY BE SOME DECENT RAIN IN SPOTS TODAY...MOSTLY WEST OF THE 55
CORRIDOR. MOISTURE IS ALREADY SLOWLY INCREASING AND THERE WILL BE A
BELT OF LL MOISTURE STREAMING NNW ACROSS THE WRN HALF OF THE CWA
TODAY. THIS BELT WILL PROVIDE SOME LL CONVERGENCE AND IS ALREADY
EVIDENT TO OUR SW AS SHRA ACTIVITY HAS PICKED UP IN THE GULF JUST
OFF THE SWRN LA COAST. AS THIS AREA MOVES OVER OUR CWA A WEAK
IMPULSE WILL ALSO APPROACH THE REGION CURRENTLY MOVING THROUGH THE
BIG BEND REGION OF TX. THIS SHOULD LEAD TO SCT CONVECTION THIS
AFTERNOON ACROSS MUCH OF THE CWA WEST OF THE PEARL RIVER WITH THE
HIGHEST POPS AROUND THE BTR METRO.

NOT MUCH HAS CHANGED IN THE THINKING FOR THU AND FRI. THE L/W TROUGH
MOVING ACROSS THE PLAINS WILL SHARPEN AND CONTINUE TO SLIDE EAST. SW
FLOW ALOFT WILL INCREASE OVER THE REGION WITH GREATER BROAD SCALE
LIFT IN PLACE ON THU. COMBINE THAT WITH ABUNDANT MOISTURE AND BROAD
DIVERGENCE ALOFT WE WILL LIKELY SEE SCT TO POSSIBLY NUMEROUS SHRA
AND TSRA THU. CONVECTION WILL LIKELY TAPER OFF SOME THU EVNG BUT
AFTER MIDNIGHT THINGS WILL BEGIN TO PICK BACK UP AS OUR COLD FRONT
FRONT APPROACHES.

OUR L/W TROUGH OVER THE CNTRL CONUS WILL CONTINUE TO PUSH EAST WITH
THE TROUGH AXIS APPROACHING THE MS VALLEY OVERNIGHT THU DRIVING OUR
COLD FRONT INTO THE MID AND LOWER MS VALLEY WELL BEFORE SUNRISE FRI.
THIS FRONT WILL HAVE AMPLE FORCING AND COULD REACH THE COAST BY
MIDDAY/EARLY AFTN FRI. SHRA AND TSRA WILL HAVE LITTLE TROUBLE
DEVELOPING AHEAD AND WITH THE FRONT WITH SOME LINGERING LIGHT SHRA
IMMEDIATELY BEHIND THE FRONT. AFTER FRONTAL PASSAGE MUCH COLDER AND
DRIER AIR WILL QUICKLY BE ON ITS HEELS. STILL NOT OVERLY IMPRESSED
WITH THE STRONG/SVR POTENTIAL. THERE WILL BE SOME INSTABILITY TO
WORK WITH AND THE MID LVL FLOW IS A TAD BETTER WITH H5 WINDS NEAR 40
KTS. SHEAR WILL NOT BE SUBSTANTIAL UNTIL AFTER FRONTAL PASSAGE.
AHEAD OF THE FRONT 0-6KM BULK SHEAR ONLY APPROACHES 20KTS.
DIRECTIONAL SHEAR IS ALSO LACKING WITH WINDS TRYING TO GO
UNIDIRECTIONAL BEFORE 18Z. MID LVL LAPSE RATES CONTINUE TO BE RATHER
SHALLOW AT OR BELOW 6 C/KM AND VT WILL ONLY BE AROUND 24-25C. AGAIN
CANT RULE OUT A ROGUE STRONG/SVR STORM OR TWO BUT OVERALL NOT
IMPRESSED WITH THE SVR POTENTIAL WITH THIS SYSTEM. THE LOCATIONS
WITH THE GREATEST RISK OF SEEING ANY STRONG STORMS IS ALONG AND NW
OF A LINE FROM BATON ROUGE TO FRANKLINTON. /CAB/

.LONG TERM...NOTHING HAS REALLY CHANGED IN THE EXTENDED PORTION OF
THE FCST. THE MEDIUM RANGE MDLS CONTINUE TO SHOW VERY PLEASANT
AUTUMN WEEKEND IN STORE. MDLS CONTINUE TO TREND A TAD COOLER WITH
THE ECMWF STILL THE COLDEST. AGAIN WILL USE A BLEND OF THE MDLS BUT
WILL GIVE A LITTLE MORE WEIGHT TO THE ECMWF GIVEN THE TRENDS.

HEADING INTO FRI NIGHT AND THIS WEEKEND LOOK FOR OUR FIRST REAL
TASTE OF AUTUMN. STRONG COLD AIR ADV OVERNIGHT FRI AND THE MDLS HAVE
COME IN A LITTLE STRONGER AND FASTER WITH THIS. THIS CAA WILL
OVERCOME ANY MIXING FROM WINDS AND SHOULD COOL THINGS OFF
IMPRESSIVELY WITH LOWS SAT MORNING LIKELY RANGING FROM THE MID 50S
IN SWRN MS TO MID 60S ALONG THE COAST. IF THE FRONT IS ANY FASTER
THEN LOWS COULD BE A FEW DEGREES COOLER. THAT SAID LOOK FOR SUN
MORNING TO BE THE COLDEST MORNING SINCE MID MAY. AS FOR HIGHS ON
SAT...H925 TEMPS OF 15C WOULD SUGGEST HIGHS STRUGGLING TO GET OUT OF
THE 70S!!! COMBINE THAT WITH RATHER BREEZY CONDITIONS FOR MUCH OF
THE DAY AND RATHER DECENT MIXING SHOULD HELP KEEP HIGHS IN THE MID
70S FOR MUCH OF THE AREA.

NOW LOOKING AT SAT NIGHT...DEWPOINTS ARE EXPECTED TO DROP INTO THE
LOWER 40S IF NOT THE 30S ACROSS THE REGION AND SAT NIGHT OPTIMAL RAD
COOLING CONDITIONS COULD SET UP. THERE ARE SOME TIMING DIFFERENCES
B/T THE MDLS WITH RESPECT TO THE SFC HIGH BUT IT LOOKS LIKE IT WILL
SIT RIGHT OVER THE REGION THAT NIGHT PROVIDING RATHER LIGHT WINDS.
SKIES SHOULD BE CLEAR AND LL TEMPS WILL NOT BE WARMING YET AND ALL
OF THIS WOULD BE GREAT FOR RAD COOLING POTENTIAL. IF THE SFC HIGH
PUSHES EAST A TAD FASTER THAN WE MAY START TO SEE RETURN FLOW IN THE
LL WHICH COULD HURT LOWS BUT THE OTHER LIMITING FACTOR COULD BE
GROUND MOISTURE. IF WE OVERACHIEVE WITH THE RAINFALL ON FRI THEN
THERE COULD STILL BE ENOUGH MOISTURE TO HURT THE COOLING POTENTIAL.
AS MENTIONED EARLIER THE TREND FROM ALL OF THE MLDS HAS BEEN TO GO A
LITTLE COOLER WITH EACH MDL RUN AND THIS HAS BEEN THE CASE FOR 4
DAYS NOW. SEE NO REASON TO DISAGREE WITH THIS AND HAVE DROPPED LOWS
ANOTHER FEW DEGREES IN THE FCST. THE ECMWF HAS BEEN THE MOST BULLISH
AND ACTUALLY SHOWS MID 40S IN SWRN MS AND SOME LOCATIONS OF SELA
ALONG THE 10/12 CORRIDOR (45 TO BE EXACT IN MCB AND ASD). STILL NOT
GOING TO GO THAT LOW BUT WILL SHOW UPPER 40S AND RIGHT AT 50 FOR
SOME AREAS. ECMWF GUI ACTUALLY SHOWS THE COLDEST READING OF 42 AT
PQL AND THIS WOULD BE THANKS TO COLD AIR DRAINAGE IN THE PASCAGOULA
RIVER BASIN.

TEMPS BEGIN TO MODERATE SUN BUT WE WILL STILL BE ON THE COOL SIDE
FOR HIGHS SUN AND LOWS MON MORNING. ANOTHER WEAK REINFORCING FRONT
LOOKS TO TRY TO APPROACH THE REGION MID WEEK. /CAB/

&&

.AVIATION...

PATCHY LIGHT FOG IS LIKELY THROUGH 13-14Z AT ALL TAF SITES...A FEW
POINTS...MCB...ASD...BXA AND HDC MAY EXPERIENCE IFR CONDITIONS WITH
VSBY AND CEILING RESTRICTIONS THROUGH 12Z. MOISTURE SURGE TODAY WILL
BRING SOME MVFR CIGS ALONG WITH ISOLATED TO SCATTERED SHRA/TSRA
MAINLY WEST OF LAKE PONTCHARTRAIN. HAVE MAINTAINED PROB30 STATEMENT
FOR TSRA DURING THE LATER MORNING INTO THE AFTERNOON AND WILL
CONVERT TO TEMPO BTR...MCB AND BTR. 18

&&

.MARINE...

LIGHT EAST TO SOUTHEAST FLOW WILL PREVAIL TODAY THROUGH EARLY
FRIDAY. THIS FLOW WILL INCREASE TONIGHT 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 LATE FRIDAY AFTERNOON INTO
FRIDAY EVENING. 1000 TO 700MB THICKNESS LAYERS WILL HOVER AROUND
3045M BEFORE THE FRONTAL PASSAGE. STRONG COLD AIR ADVECTION AFTER
THE FRONT WILL ALLOW LAYERS TO DROP TO 2990M BY SATURDAY 12Z AND NOW
GFS HOLDS THE THIS LAYER THROUGH THROUGH SUNDAY MORNING...SIMILAR TO
EURO. GFS HAS THE SURFACE HIGH OVER THE LOWER MISSISSIPPI VALLEY
WHILE EURO HAS THE HIGH OVER CENTRAL TEXAS COAST. BOUNDARY LAYER
WINDS OF 23 TO 25 KNOTS WILL MIXED DOWN 100 PERCENT TO SEA SURFACE
FRIDAY NIGHT THROUGH SATURDAY MORNING. AS A RESULT...A SMALL CRAFT
ADVISORY HEADLINES WILL LIKELY BE NEEDED FOR ALL COASTAL WATERS
FRIDAY NIGHT INTO SATURDAY. 18

&&

.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  86  72  85  71 /  40  40  60  60
BTR  87  72  86  73 /  50  40  60  60
ASD  86  73  86  73 /  30  30  60  50
MSY  86  76  87  76 /  50  40  60  50
GPT  85  74  84  74 /  20  30  50  50
PQL  86  70  85  73 /  20  20  50  50

&&

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

$$

SHORT/LONG TERM: CAB
AVIATION/MARINE: 18




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