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

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FXUS64 KLIX 280051
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
651 PM CST THU NOV 27 2014

...SOUNDING DISCUSSION...

THE NOCTURNAL BOUNDARY LAYER WAS BEGINNING TO DEVELOP ALLOWING
DECOUPLING TO OCCUR AND SURFACE WINDS TO BECOME LIGHTER AS THE
BALLOON BEGAN ITS ASCENT. WINDS ALOFT ARE STILL STRONG...BUT NOT AS
STRONG AS THE PAST COUPLE OF DAYS. A PEAK WIND OF 81 KNOTS WAS
LOCATED AT 48300 FEET. WINDS WERE FROM THE NORTH AT THE SURFACE
AND THEN BACKED TO FROM THE WEST-NORTHWEST AROUND 15000 FEET.
ANOTHER TEMPERATURE INVERSION WAS LOCATED AROUND 925 TO 850 MB AND
IN THIS LAYER IT WAS QUITE DRY. OVERALL...THE SOUNDING IS DRY AS
IS TYPICAL FOR LATE NOVEMBER WITH A PRECIPITABLE WATER VALUE OF
0.42 INCHES.

00Z BALLOON INFO: A SUCCESSFUL FLIGHT THIS EVENING THAT LASTED 103
MINUTES AND REACHED A HEIGHT OF 20.4 MILES ABOVE THE GROUND
BEFORE BURSTING OVER THE GULF OF MEXICO NEAR HORN ISLAND SOUTH OF
BILOXI 66 MILES DOWNRANGE.

ANSORGE

&&

.PREV DISCUSSION... /ISSUED 307 PM CST THU NOV 27 2014/

SYNOPSIS...

AXIS OF SURFACE HIGH PRESSURE EXTENDS FROM IOWA TO NORTHERN
LOUISIANA THIS AFTERNOON. LITTLE IN THE WAY OF CLOUDS ACROSS THE
AREA THIS AFTERNOON...AND NONE REALLY EXPECTED THROUGH TOMORROW.
IT HAS BEEN A COOL AND DRY THANKSGIVING DAY WITH TEMPERATURES
GENERALLY AROUND 60 AT MID-AFTERNOON AND DEW POINTS AROUND 30. A
NORTH BREEZE AT 10 TO 15 MPH HAS PROBABLY MADE IT FEEL A LITTLE
COOLER THAN THAT.

SHORT TERM...

HIGH PRESSURE WILL SLOWLY MOVE EASTWARD OVER THE NEXT FEW DAYS AND
BE OFF THE ATLANTIC COAST ON SUNDAY. NOT MUCH IN THE WAY OF
MOISTURE RETURN...EVEN THROUGH SUNDAY. WITH WIND BECOMING ONSHORE
BY LATE FRIDAY OR SATURDAY...CANNOT RULE OUT A LITTLE BIT OF FOG
OR LOW CLOUDS DURING THE LATE NIGHT/EARLY MORNING HOURS SATURDAY
AND SUNDAY MORNINGS...BUT CONFIDENCE NOT HIGH ENOUGH TO MENTION IN
THE FORECAST AT THIS TIME. NO PRECIPITATION THROUGH THE WEEKEND.

OVERNIGHT LOWS TONIGHT WILL DROP TO NEAR FREEZING IN THE NORMALLY
COLDER LOCATIONS. THESE AREAS HAVE HAD SEVERAL FREEZES...SO NO
WARNINGS NECESSARY. POSSIBLE LIMITING FACTOR WOULD BE IF THE WIND
STAYS UP AROUND 5 MPH...THEN FORECAST LOWS WOULD BE TOO COOL. HIGH
TEMPERATURES TOMORROW WILL BE SIMILAR TO TODAYS. TEMPERATURES THEN
BEGIN TO MODERATE AS ONSHORE FLOW RETURNS. HAVE TAKEN A BLEND OF
GUIDANCE APPROACH FOR TEMPERATURES...GENERALLY SHADED TOWARD THE
WARMER GUIDANCE. 35

LONG TERM...

BEYOND MONDAY...FORECAST CONFIDENCE DIMINISHES CONSIDERABLY AS
ECMWF AND GFS PRETTY MUCH BECOME COMPLETELY OUT OF PHASE BY MID-
WEEK. A BLENDED APPROACH LEANING TOWARD THE ECMWF SOLUTION HAS
BEEN USED. THIS BRINGS SOME MENTION OF PRECIPITATION FOR MONDAY
THROUGH WEDNESDAY...BUT NOT MUCH MORE THAN 20-30 PERCENT AT THIS
TIME. HAVE ALSO DONE THIS WITH THE TEMPERATURE FORECAST TO FIT
WITH NEIGHBORING OFFICES...BUT WILL NOTE THAT IF GFS SOLUTION
PREVAILS AT MID-WEEK NEXT WEEK...TEMPERATURE FORECAST WILL HAVE TO
BE INCREASED BY 5 TO 10 DEGREES FROM CURRENT FORECAST. 35

AVIATION...

STEADY NORTH WINDS WILL RELAX AROUND MIDNIGHT...LENDING TO LIGHT
NORTHEAST WINDS OVERNIGHT AT MOST TERMINALS. MSY AND NEW WILL REMAIN
ELEVATED AS CAA INCREASES SPEEDS OVER LAKE PONTCHARTRAIN. RIDGE
SLIDING EAST WILL ALLOW WIND DIRECTION TO KEEP ROTATING AROUND TO
ONSHORE FLOW TOMORROW. NO CLOUD COVER OF ANY SIGNIFICANCE EXPECTED.

MEFFER

MARINE...

A REINFORCEMENT OF CONTINENTAL COOL HIGH PRESSURE WILL BE TAKING
PLACE OVERNIGHT. WRF MESO MODEL SEEMS TO BE PICKING UP ON THIS AND
SUGGESTING A NOCTURNAL INCREASE IN WINDS IN THE COASTAL WATERS. AS
FAR AS HOW STRONG...IT APPEARS WINDS WILL BE BORDERLINE SCS AND SCA.
THINKING IS THAT THE PRESSURE GRADIENT WILL BE SUCH THAT STEADY 20
KNOT WINDS WILL EXIST IN OFFSHORE WATERS EAST OF THE MS RIVER.
EVERYWHERE ELSE SHOULD AT LEAST BE 15 KNOTS. SO HAVE ISSUED EXERCISE
CAUTION AND ADVISORY ACCORDINGLY. SHOULD BE A SHORT EVENT WITH THE
CENTER OF THE RIDGE REACHING THE NORTHERN GULF COAST BY NOON FRIDAY.
THEREFORE WILL BE IN EFFECT. HIGH PRESSURE IS EXPECTED TO INFLUENCE
THE WIND FIELD THROUGH THE WEEKEND BEFORE MOVING EAST AND MODERATING
LATTER PART OF THE WEEKEND. ONSHORE FLOW ONSETS AHEAD OF NEXT HIGH
PRESSURE SURGE EARLY NEXT WEEK. LATEST MODEL RUNS NOW SHOW THE FRONT
MAKING IT TO THE COAST...MAYBE HIGH PRESSURE BRIDGING THE FRONT INTO
THE NORTH GULF LATER NEXT WEEK.

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  32  60  44  69 /   0   0   0  10
BTR  34  63  48  72 /   0   0   0  10
ASD  34  60  44  70 /   0   0   0   0
MSY  42  62  51  71 /   0   0   0   0
GPT  37  59  47  69 /   0   0   0   0
PQL  33  59  41  70 /   0   0   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM FRIDAY FOR THE FOLLOWING ZONES:
     BRETON SOUND...CHANDELEUR SOUND...COASTAL WATERS FROM
     BOOTHVILLE LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI
     RIVER OUT 20 NM...COASTAL WATERS FROM PASCAGOULA MS TO
     STAKE ISLAND LA FROM 20 TO 60 NM...COASTAL WATERS FROM
     PASCAGOULA MS TO STAKE ISLAND LA OUT 20 NM...AND COASTAL
     WATERS FROM STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER FROM 20 TO 60 NM.

MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM FRIDAY FOR THE FOLLOWING ZONES:
     BRETON SOUND...CHANDELEUR SOUND...COASTAL WATERS FROM
     BOOTHVILLE LA TO THE SOUTHWEST PASS OF THE MISSISSIPPI
     RIVER OUT 20 NM...COASTAL WATERS FROM PASCAGOULA MS TO
     STAKE ISLAND LA FROM 20 TO 60 NM...COASTAL WATERS FROM
     PASCAGOULA MS TO STAKE ISLAND LA OUT 20 NM...AND COASTAL
     WATERS FROM STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE
     MISSISSIPPI RIVER FROM 20 TO 60 NM.

&&

$$






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