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

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160
FXUS64 KLIX 242040
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
340 PM CDT SUN AUG 24 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED OVER VIRGINIA THIS AFTERNOON WITH A WEAKER
HIGH PRESSURE AXIS FROM ARKANSAS INTO THE WESTERN GULF. WHAT IS
EFFECTIVELY A BACKDOOR COLD FRONT IS ALONG THE GEORGIA-ALABAMA
BORDER INTO NORTHEAST FLORIDA. THERE IS SCATTERED TO BROKEN
CONVECTION MOVING WEST WITH THIS FEATURE. LOCALLY...VERY LITTLE
CONVECTION IS OCCURRING AT THIS TIME. SKIES ARE MOSTLY SUNNY
ACROSS THE AREA. AFTERNOON TEMPERATURES HAVE BEEN MORE DEPENDENT
ON DEW POINTS THAN ANYTHING. AREAS THAT HAVE MIXED DOWN SOME DRIER
AIR HAVE SEEN DEW POINTS FALL INTO THE MID AND UPPER 60S...AND
HAVE HAD TEMPERATURES INTO THE 95 TO 100 RANGE...WITH BILOXI
SITTING AT 100 THIS HOUR. WHERE DEW POINTS HAVE REMAINED IN THE
MID AND UPPER 70S...TEMPERATURES ARE GENERALLY IN THE MID 90S.
HEAT INDEX READINGS RANGE FROM 100 TO 109 AT THIS HOUR.

&&

.SHORT TERM...

FORECAST QUESTION FOR TONIGHT IS WHETHER CONVECTION ALONG THE
BACKDOOR FRONT REACHES THE AREA. WOULD EXPECT SOMEWHAT OF A
DIMINISHING TREND WITH THE LOSS OF SURFACE HEATING...BUT WITH THE
FORWARD SPEED OF THE FEATURE...CONVECTION COULD REACH THE EASTERN
PORTIONS OF OUR AREA AS EARLY AS 04-05Z...SO WILL GO A BIT HIGHER
THAN GUIDANCE ON POPS TONIGHT. UPPER IMPULSE WORKING CLOCKWISE
AROUND THE UPPER RIDGE IS EXPECTED TO AFFECT THE AREA DURING THE
AFTERNOON ON MONDAY...AND CONCUR WITH GUIDANCE POPS IN THE LIKELY
RANGE. THIS WILL ALSO BRING COOLING TO THE AREA...SO ONCE HEAT
INDEX READINGS FALL THIS EVENING...ANTICIPATE CANCELLATION OF HEAT
ADVISORY...AND IT LOOKS LIKE WE SHOULD NOT NEED ONE TOMORROW. CELL
MOVEMENT ON STORMS TOMORROW SHOULD BE IN THE 8-10 KNOT RANGE. IF
REPEAT CONVECTION OCCURS IN ANY LOCATION...HEAVY RAIN IS LIKELY TO
BE AN ISSUE AS PRECIPITABLE WATER VALUES ON THE BUFR SOUNDINGS IS
AROUND 2.25 INCHES. THERE WILL ALSO BE A SMALL THREAT OF DAMAGING
WINDS...AND SPC HAS 5 PERCENT PROBABILITIES FOR TOMORROW ACROSS
THE AREA.

AFTER IMPULSE MOVES WEST OF THE AREA MONDAY AFTERNOON OR
EVENING...RIDGE SHOULD REBUILD BACK INTO THE AREA WITH LOWER RAIN
CHANCES RETURNING FOR TUESDAY AND WEDNESDAY. TEMPERATURES WILL
ALSO RETURN TO MORE SEASONABLE LEVELS. 35

&&

.LONG TERM...

UPPER RIDGE SHIFTS EASTWARD TO FLORIDA BY THE END OF THE WEEK AS
AN UPPER TROF MOVES INTO THE GREAT PLAINS. THIS WILL ALLOW RAIN
CHANCES TO AGAIN INCREASE A BIT FOR NEXT WEEKEND...AROUND 40
PERCENT ON SATURDAY AND SUNDAY. TEMPERATURES WILL BE SLIGHTLY
ABOVE NORMAL FOR THE WEEKEND...90 TO 95. 35

&&

.AVIATION...

MOSTLY VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH MONDAY
MORNING...HOWEVER CONDITIONS MAY LOWER TO MVFR TO BRIEFLY IFR DURING
ISOLATED TO SCATTERED SHRA/TSRA TONIGHT WITH A BETTER CHANCE OF
LOWER CONDITIONS IN MORE WIDESPREAD SHRA/TSRA DEVELOPING ON MONDAY.
HAVE NOT CARRIED THESE LOWER CONDITIONS AS PREVAILING OR TEMPO DUE
TO UNCERTAINTY IN TIMING...HOWEVER A PROB30 STATEMENT MAY BE
APPROPRIATE AT SOME POINT TONIGHT WITH TEMPO TO PREVAILING
DEVELOPING ON MONDAY. NEXT UPDATED OR REGULARLY UPDATED TAFS WILL
HOPEFULLY HAVE A BETTER HANDLE ON TIMING OUTFLOW BOUNDARIES AND
OTHER FEATURES THAT WILL FOCUS THE CONVECTION. 22/TD

&&

.MARINE...

WEAK HIGH PRESSURE TO THE WEST AND NORTH OF THE COAST WILL MAINTAIN
MOSTLY NORTHERLY WINDS THROUGH THIS EVENING. A WEAK BACKDOOR COLD
FRONT WILL MOVE FROM NORTHEAST TO SOUTHWEST ACROSS THE COASTAL
WATERS TONIGHT AND MONDAY. REINFORCING HIGH PRESSURE WILL BUILD FROM
A LARGE HIGH PRESSURE RIDGE OVER THE ATLANTIC COAST STATES IN THE
WAKE OF THE FRONT MONDAY INTO TUESDAY. AN UPPER LEVEL DISTURBANCE
MOVING FROM EAST TO WEST ACROSS THE CENTRAL GULF COAST REGION IS
LIKELY TO PRODUCE SOME STRONG THUNDERSTORMS WITH STRONG GUSTY
WINDS...FREQUENT LIGHTNING...AND TORRENTIAL DOWNPOURS POSSIBLY
STARTING TONIGHT AND CONTINUING IN WAVES...MOSTLY ALONG AND SOUTH OF
THE FRONTAL BOUNDARY...THROUGH TUESDAY MORNING.

THE PRESSURE GRADIENT WILL TIGHTEN AND RESULT IN EASTERLY WINDS OF
15 TO 20 KNOTS OVER MUCH OF THE MARINE AREA FOR MUCH OF THE PERIOD
FROM MONDAY THROUGH WEDNESDAY. HEADLINES FOR /SMALL CRAFT EXERCISE
CAUTION/ MAY BE NECESSARY STARTING MONDAY...AND SMALL CRAFT
ADVISORIES COULD BE REQUIRED FOR SOME OF THE COASTAL WATERS ZONES ON
TUESDAY. HIGH PRESSURE WILL WEAKEN AND THE WINDS WILL SUBSIDE TO
EITHER 10 TO 15 KNOTS OR AROUND 10 KNOTS THURSDAY AND FRIDAY. 22/TD

&&

.DECISION SUPPORT...

DSS CODE...YELLOW.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...HEAT ADVISORY...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  74  91  71  92 /  30  60  20  20
BTR  76  93  74  93 /  30  60  20  30
ASD  76  90  73  92 /  30  60  20  20
MSY  81  91  77  91 /  30  60  20  30
GPT  78  90  75  91 /  40  60  20  20
PQL  77  90  71  91 /  40  60  20  10

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...HEAT ADVISORY UNTIL MIDNIGHT MONDAY FOR THE FOLLOWING ZONES:
     ASCENSION...ASSUMPTION...EAST BATON ROUGE...EAST
     FELICIANA...IBERVILLE...LIVINGSTON...LOWER
     JEFFERSON...LOWER LAFOURCHE...LOWER PLAQUEMINES...LOWER ST.
     BERNARD...LOWER TERREBONNE...NORTHERN
     TANGIPAHOA...ORLEANS...POINTE COUPEE...SOUTHERN
     TANGIPAHOA...ST. CHARLES...ST. HELENA...ST. JAMES...ST.
     JOHN THE BAPTIST...ST. TAMMANY...UPPER JEFFERSON...UPPER
     LAFOURCHE...UPPER PLAQUEMINES...UPPER ST. BERNARD...UPPER
     TERREBONNE...WASHINGTON...WEST BATON ROUGE...AND WEST
     FELICIANA.

GM...NONE.
MS...HEAT ADVISORY UNTIL MIDNIGHT MONDAY FOR THE FOLLOWING ZONES:
     AMITE...HANCOCK...HARRISON...JACKSON...PEARL
     RIVER...PIKE...WALTHALL...AND WILKINSON.

GM...NONE.
&&

$$







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