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

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000
FXUS64 KLIX 212029
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
329 PM CDT THU AUG 21 2014

.SHORT TERM...

A STRONG H5 595 RIDGE WILL REMAIN PARKED OVER THE GULF SOUTH
THROUGH SATURDAY. THE RIDGE WILL WEAKEN SLIGHTLY ON SUNDAY
DROPPING DOWN TO AROUND A 590 RIDGE...BUT WILL STILL BE STRONG
ENOUGH TO KEEP CONVECTIVE CHANCES DOWN AND TEMPERATURES UP.
OVERALL RAIN CHANCES WILL BE HIGHEST ALONG THE COAST OF LOUISIANA
WHERE SEABREEZE BOUNDARY INTERACTIONS SHOULD BE SUFFICIENT TO
OVERCOME ANY CAPPING ALOFT AND ALLOW FOR DEEPER CONVECTION TO
FORM. OVERALL...EXPECT TO SEE SIMILAR PATTERNS OF CONVECTIVE
DEVELOPMENT AS OBSERVED THE LAST COUPLE OF DAYS. THE CONVECTION
WILL TEND TO DEVELOP DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS WHEN THE TEMPERATURE AND OVERALL CONVECTIVE INSTABILITY IS
MAXIMIZED. AWAY FROM THE SEABREEZE INDUCED CONVECTION...VERY
LITTLE IN THE WAY OF CONVECTION IS EXPECTED DUE TO THE WEAK LAPSE
RATES ALOFT. IF ANY CONVECTION FORMS IN NORTHERN AND EASTERN
ZONES...IT WILL BE DUE TO THE CONVECTIVE TEMPERATURE BEING
REACHED AND THE WEAK CAP ALOFT BEING BROKEN. HAVE PUT IN SLIGHT
CHANCE POPS FOR ALL OF THE AREA EACH AFTERNOON.

TEMPERATURES WILL BE A GOOD 5 DEGREES ABOVE AVERAGE THROUGH
SUNDAY...WITH HIGHS RANGING FROM THE MIDDLE TO UPPER 90S.
DEWPOINTS WILL GENERALLY RANGE AROUND 70 DEGREES THROUGH
SATURDAY...KEEPING HEAT INDEX READINGS BETWEEN 100 AND 105.
HOWEVER...AS THE RIDGE ALOFT WEAKENS THE ATMOSPHERE WILL BEGIN TO
MOISTEN A BIT. WITH DEWPOINTS RISING TO AROUND 75 DEGREES FOR
SUNDAY AND MONDAY...HEAT INDEX READINGS WILL CLIMB CLOSER TO 110
DEGREES. OVERNIGHT LOWS WILL ALSO BE HIGHER...WITH LOWS STRUGGLING
TO DROP BELOW 80 DEGREES IN METRO NEW ORLEANS SUNDAY NIGHT. THESE
MORE OPPRESSIVE CONDITIONS COULD PROMPT THE ISSUANCE OF HEAT
ADVISORIES FOR SUNDAY AND MONDAY.

.LONG TERM...

RAIN CHANCES ON MONDAY WILL BEGIN TO INCREASE LATE IN THE DAY...AS
THE UPPER LEVEL RIDGE CONTINUES TO WEAKEN AND THE RIDGE AXIS
SHIFTS TO THE NORTH AND WEST OF THE GULF COAST. A WEAK UPPER LEVEL
VORT MAX AND ASSOCIATED FORCING WILL SLIDE TOWARD THE AREA DURING
THE DAY ON MONDAY. A BROAD REGION OF INCREASED POSITIVE VORTICITY
ADVECTION SHOULD PROVIDE ENOUGH OMEGA TO PRODUCE SCATTERED
CONVECTION OVER THE EASTERN HALF OF THE FORECAST AREA MONDAY
AFTERNOON. HAVE KEPT IN CHANCE POPS TO REFLECT THIS RISK. THERE
WILL ALSO BE HIGHER RISK OF STRONG WINDS WITH THE DEEPEST
CONVECTION ON MONDAY AS DRY AIR IN THE MID-LEVELS BECOMES
ENTRAINED INTO THE STORMS.

THE MAIN SURGE OF MOISTURE AND OMEGA WILL OVERSPREAD THE AREA ON
TUESDAY AND LINGER INTO WEDNESDAY. HAVE KEPT IN CHANCE POPS FOR
THE ENTIRE FORECAST AREA EACH DAY. PW VALUES WILL RISE TO AROUND
2 INCHES WHICH INDICATES THAT A VERY TROPICAL AIRMASS WILL BE IN
PLACE. EXPECT TO SEE CONVECTION SPREAD INLAND FROM THE OFFSHORE
WATERS BY LATE MORNING AND THEN TURN MORE WIDESPREAD DURING THE
AFTERNOON HOURS. STORM MOTIONS WILL BE RELATIVELY SLOW...SO
LOCALLY HEAVY RAINFALL OF 2 TO3 INCHES IN AN HOUR WILL BE ENTIRELY
POSSIBLE WITH THE DEEPEST CONVECTION. WITH THE GREATER CLOUD COVER
AND RAINFALL IN THE AREA...TEMPERATURES WILL FALL BACK TO MORE
NORMAL LEVELS FOR LATE AUGUST. HIGHS WILL CLIMB INTO THE LOWER 90S
AND OVERNIGHT LOWS WILL GENERALLY BE IN THE LOWER TO MIDDLE 70S.

&&

.AVIATION...

VFR CONDITIONS SHOULD PREVAIL THROUGH THE PERIOD. ISOLATED SHOWERS
AND THUNDERSTORMS WILL PERSIST THROUGH THIS AFTERNOON. HAVE INCLUDED
VICINITY AND TEMPO GROUPS AT TERMINALS WHERE THUNDERSTORMS ARE MOST
LIKELY. OUTSIDE OF ANY CONVECTIVE INFLUENCES...EXPECT LIGHT WINDS
AND CLOUD BASES AROUND 4KFT DURING THE DAY...WITH LIGHT OR CALM
WINDS AND ONLY HIGH CLOUDS OVERNIGHT.

&&

.MARINE...

A RIDGE CENTERED OVER THE AREA...MESOSCALE INTERACTIONS WILL DRIVE
THE WIND IN THE COASTAL WATERS. A SEABREEZE/LANDBREEZE CYCLE WILL
DOMINATE...WITH OFFSHORE WINDS IN PLACE DURING THE MORNING HOURS
AND ONSHORE WINDS DEVELOPING DURING THE AFTERNOON HOURS. WINDS
WILL GENERALLY BE 10 KNOTS OR LESS THROUGH THE WEEKEND...AND SEAS
WILL GENERALLY BE 2 FEET OR LESS. THE WINDS WILL TAKE ON A MORE
PERSISTENT EASTERLY FLOW EARLY NEXT WEEK AS THE SURFACE HIGH
BECOMES CENTERED NORTH OF THE REGION. EAST WINDS OF 10 TO 15 KNOTS
AND SEAS OF 2 TO 3 FEET CAN BE EXPECTED MONDAY AND TUESDAY.

&&

.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  74  95  74  97 /  10  20  20  20
BTR  76  96  75  97 /  10  20  20  20
ASD  76  94  76  96 /  10  20  20  20
MSY  77  93  78  95 /  10  20  20  20
GPT  77  95  77  97 /  10  20  20  20
PQL  75  96  75  96 /  10  20  20  20

&&

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

$$

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