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

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520
FXUS64 KLIX 201335
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
735 AM CST TUE JAN 20 2015


.SOUNDING DISCUSSION...

THE SOUNDING THIS MORNING HAD CALM WINDS AT THE SFC AND WESTERLY
WINDS JUST ABOVE. THERE IS A STRONG 14 F INVERSION AT 1200 FT. THE
JET MAX IS 100 KTS AT 175 MB. ABOVE THE SURFACE LAYER THE AIRMASS
IS MAINLY DRY WITH A PW OF .68 INCHES.

&&


.PREV DISCUSSION... /ISSUED 304 AM CST TUE JAN 20 2015/

SYNOPSIS...

HIGH PRESSURE EXTENDS FROM FLORIDA ACROSS MUCH OF THE NORTHERN
GULF OF MEXICO. LOW PRESSURE NEAR THE CONFLUENCE OF THE OHIO AND
MISSISSIPPI RIVERS HAS A COLD FRONT TRAILING SOUTHWEST INTO TEXAS
EARLY THIS MORNING. SATELLITE AND SURFACE OBSERVATIONS INDICATE A
BAND OF CLOUDS MOVING ACROSS THE AREA WITH CEILINGS BETWEEN 2500
AND 5000 FEET. AWAY FROM MARINE INFLUENCES...TEMPERATURES ARE
GENERALLY IN THE 40S WITH LIGHT WINDS.

SHORT TERM...

NOT MUCH HAS CHANGED IN THE SHORT TERM PORTION OF THE FORECAST. A
STRONG SHORTWAVE MOVING THROUGH THE SOUTHERN GREAT LAKES WILL PUSH
THE COLD FRONT THROUGH THE AREA LATE TONIGHT INTO WEDNESDAY
MORNING. THERE IS BASICALLY NO MOISTURE WITH THIS FRONT...AND
OTHER THAN SOME CLOUDS...NOT MUCH CHANGE IN AIRMASS.

UPPER SYSTEM MOVING THROUGH THE 4 CORNERS PORTION OF THE COUNTRY
WILL START TO SET UP SOME ISENTROPIC UPGLIDE DURING THE DAY ON
THURSDAY. COULD START TO SEE SOME LIGHT PRECIPITATION AS EARLY AS
THURSDAY MORNING...BUT MORE LIKELY TO OCCUR THURSDAY AFTERNOON.
HAVE GONE WITH CATEGORICAL POPS FOR THURSDAY NIGHT...BUT COULD
STILL BUMP UP ANOTHER 10 PERCENT IN A LATER FORECAST. THERMAL
PROFILE AT MCCOMB THURSDAY NIGHT INDICATES NO REAL THREAT OF
WINTRY PRECIPITATION.

TEMPERATURE GUIDANCE LOOKS PRETTY CONSISTENT THROUGH
THURSDAY...ALTHOUGH I CANNOT EXPLAIN WHY ECMWF WOULD INDICATE 75
AT BATON ROUGE TODAY. WILL KEEP IT CLOSER TO 70 THERE. IF RAIN
ONSETS TOO EARLY ON THURSDAY...MAY NEED TO TRIM HIGHS THERE. 35

LONG TERM...

MAIN DIFFERENCE IN FORECAST PACKAGE FROM 24 HOURS AGO IS THAT ALL
MODELS ARE SLOWER IN MOVING SOUTHERN STREAM SYSTEM ACROSS THE AREA
ON FRIDAY. THIS WILL NECESSITATE HOLDING ON TO RAIN CHANCES INTO
FRIDAY NIGHT...BUT WILL NOT KEEP CHANCES AS HIGH AS ECMWF SOLUTION
INDICATES. BEYOND FRIDAY NIGHT...LITTLE OR NO PRECIPITATION FOR
REMAINDER OF THE FORECAST PERIOD.

RAIN AND CLOUD COVER WILL KEEP TEMPERATURES WELL BELOW NORMAL FOR
HIGHS ON FRIDAY. WILL START TO SEE A LITTLE SUN ON SATURDAY...AND
TEMPERATURES SHOULD FALL JUST SHORT OF NORMAL. SUNDAY THROUGH
TUESDAY TEMPERATURES ARE REMARKABLY CLOSE ON GUIDANCE. WILL TEND
TOWARD SLIGHTLY COOLER NUMBERS AS COOL AIR GETS REINFORCED IN
NORTHWEST FLOW. 35

AVIATION...

EXPECT MOSTLY VFR CONDITIONS AT ALL TERMINALS THROUGH THE TAF
PERIOD. THERE HAVE BEEN A FEW OBSERVATIONS THIS MORNING IN THE MVFR
CATEGORY. A FEW TERMINALS COULD SEE A BRIEF PERIOD OF MVFR
CONDITIONS EARLY THIS MORNING BUT VFR CONDITIONS WILL PREVAIL AT ALL
TERMINALS TODAY. 13/MH

MARINE...

STRONG SURFACE HIGH IS OVER THE COASTAL WATERS AND THAT HAS KEPT
WINDS LIGHT OVERNIGHT AND SHOULD KEEP THEM LOW TODAY AS WELL. WINDS
SHOULD SHIFT TO A MORE NORTHERLY DIRECTION WEDNESDAY AROUND 10 KNOTS
AS A GULF LOW BEGINS TO FORM IN THE WESTERN GULF OF MEXICO. NOT MUCH
CHANGE IN THE THINKING FOR STRONG ADVISORY TO POSSIBLE GALE FORCE
WINDS WITH THIS LOW ON THURSDAY NIGHT. WILL HAVE TO WATCH THIS
FEATURE. HAVE NOT MADE MUCH CHANGE FROM PREVIOUS FORECAST. WINDS ARE
EXPECTED TO REMAIN ELEVATED FRIDAY AS THE SURFACE LOW PASSES THROUGH
THE NORTHERN GULF. CONDITIONS WILL GRADUALLY EASE FRIDAY NIGHT INTO
SATURDAY...BUT STILL EXPECT TO SEE ADVISORY CONDITIONS THROUGH
SATURDAY MORNING AS THE SURFACE LOW AND AN ASSOCIATED FRONTAL
BOUNDARY PULL AWAY FROM THE REGION. 13/MH

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  69  44  65  44 /   0   0  10  10
BTR  71  47  68  46 /   0   0  10  10
ASD  69  46  68  46 /   0   0  10  10
MSY  70  47  67  48 /   0   0  10  10
GPT  68  46  67  45 /   0   0  10  10
PQL  70  44  68  45 /   0   0  10  10

&&

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

$$







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