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

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429
FXUS64 KLIX 122039
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
339 PM CDT FRI SEP 12 2014

.SHORT TERM...
TROPICAL MOISTURE CONTINUES TO STREAMI INLAND IN ADVANCE OF A
STATIONARY OUTFLOW BOUNDARY CURRENTLY SITUATED FROM
BIRMINGHAM...TO JACKSON...TO ALEXANDRIA AND NORTH OF HOUSTON
METROPLEX. SYNOPTIC FRONTAL ZONE REMAINS WELL NORTH OF THAT
FEATURE AND HAS ALL THE APPEARANCES OF STALLING UNDER PARALLEL
FLOW ALOFT AND OVER-RUNNING MODIFICATION. THIS PARTICULAR SET-UP
DOES NOT BODE WELL FOR THE GULF SOUTH AS THERE ARE MANY
OPPORTUNITIES FOR MESO-SCALE AND SUB-SYNOPTIC SCALE FOCI FOR HEAVY
RAIN POTENTIAL. AFTER CONSIDERABLE COORDINATION WITH HPC FOR
RAINFALL POTENTIAL OVER THE WEEKEND...WE WILL BE INDICATING A
WETTER SOLUTION THAN SYNOPTIC MODELS SUGGEST DUE IN LARGE PART FOR
ANTICIPATED INTERACTIONS OF GULF BREEZE AND LAKE BREEZE BOUNDARIES
AMONG OTHER COMPLEXITIES EVOLVING WITH THE FRONTAL ZONE IN
PROXIMITY AND ANY ATTENDENT OUTFLOW STRUCTURES THAT OCCUR. HAVING
SAID THAT...WE WILL BE INDICATING A 2 INCH ACCUMULATION AVERAGE
BULLSEYE OVER SOUTHEAST LOUISIANA WITH A 1 INCH ACCUMULAION
AVERAGE EXTENDING ALONG THE MISSISSIPPI COAST FOR SATURDAY. A
SIMILAR BULLSEYE OF AROUND 1 INCH WILL BE INDICATED FOR
SUNDAY...WHICH CAN TALLY TO AVERAGE AMOUNTS AROUND 3 INCHES FOR
THE NEXT COUPLE OF DAYS. IF ANY BANDING TAKES PLACE ALONG THESE
FOCUSING BOUNDARIES...WHICH IS HIGHLY LIKELY...THEN LOCALIZED
AMOUNTS TO 5 INCHES ARE NOT FAR-FETCHED. RAINFALL PROCESSES WILL
BE HIGHLY EFFICICIENT IN THIS SITUATION...WITH RATES AROUND 2
INCHES PER HOUR COMMON OVER THE NEXT COUPLE OF DAYS. GIVEN
ANTECEDENT CONDITIONS AND HYDROLOGIC CAPACITY...HAVE HOLD ON
ISSUING ANY FLASH FLOOD WATCH AT THIS TIME....BUT MAY HAVE TO
REVISIT TONIGHT OR EARLY SATURDAY IF CONFIDENCE GAINS WITH
SUBSEQUENT MODEL RUNS. BOTTOM LINE...CALLING FOR GENERALLY 1-3
INCHES WITH LOCALLY AROUND 5 INCHES ACCUMULATION ACROSS THE
FORECAST AREA...PRIMARILY SOUTHERN AND EASTERN PORTIONS...THROUGH
MONDAY MORNING 12Z CUT-OFF. TEMPERATURES SHOULD BE NEAR TO
SLIGHTLY ABOVE NORMAL...PARTICULARLY ON MORNING LOWS THIS
WEEKEND...BUT VARIABLE BASED ON RAINFALL COVERAGE THROUGHOUT THE
DAYTIME.

.LONG TERM...
MONDAY AND BEYOND WILL BE HIGHLY CONTINGENT ON ANY TROPICAL
DEVELOPMENTS IN THE GULF BUT THE FRONTAL ZONE IS ANTICIPATED TO BE
WASHED OUT BY THAT TIME FRAME. A WEAKER OR NON-EXTISTENT TROPICAL
DEVELOPMENT WOULD REVERT THE FORECAST BACK TO TYPICAL SUMMER
ONSHORE FLOW REGIME. A STRONGER DEVELOPMENT OF ANY TROPICAL SYSTEM
WILL LIKELY INDUCE MORE CONTINENTAL AIR INTO THE AREA AS MOISTURE
BECOMES MORE CYCLONICALLY ORIENTED. AGAIN...NOT VERY CLEAR OR
HIGHLY CONFIDENT IN FORECAST BEYOND SUNDAY BUT HAVE INDICATED A
MORE TYPICAL REGIME AT THIS TIME ON TEMPERATURES AND RAIN CHANCES.

&&

.AVIATION...
NUMEROUS SHRA AND TSRA AFFECTING MOST TERMINALS THIS AFTERNOON. THIS
IS PRODUCING TEMPORARY MVFR CIGS AND VSBYS. MOST CONVECTION SHOULD
DISSIPATE BY OR PRIOR TO 02Z. AS HAS BEEN THE CASE THE LAST FEW
NIGHTS...OVERNIGHT CONVECTION LIKELY TO DEVELOP OVER THE GULF OF
MEXICO AND COULD MOVE ONSHORE TOWARD KGPT...KHUM...KMSY AND KNEW
PRIOR TO 12Z. WHILE FOG IS POSSIBLE WHERE RAIN OCCURS THIS
AFTERNOON...PROBABILITIES NOT HIGH ENOUGH TO CARRY AS A PREVAILING
CONDITION. THE MOIST AND UNSTABLE AIRMASS WILL AGAIN BRING BROKEN
CLOUDS AND CONVECTIVE POTENTIAL TO MOST TERMINALS BY MID-MORNING
SATURDAY. WILL CARRY VCSH/VCTS DURING THE MORNING HOURS TOMORROW.

&&

.MARINE...
COASTAL FORECAST REMAINS CONTINGENT ON EVENTUAL DEVELOPMENTS IN
THE GULF OF MEXICO. THE CURRENT FORECAST WILL BE BASED ON A WIND
FIELD REFLECTIVE OF A LOW PRESSURE CIRCULATION MOVING ACROSS THE
MIDDLE GULF THROUGH THE WEEKEND INTO EARLY NEXT WEEK. WINDS REALLY
STAY BELOW 15 KNOTS FOR MUCH OF THE FORECAST PACKAGE GIVEN THE
UNCERTAINTIES OF ANY DEVELOPMENTS WITH THIS PARTICULAR SYSTEM.
THERE REMAINS A SMALL WINDOW OF OPPORTUNITY FOR SOME DEVELOPMENT
IN THE NEXT 24-48 HOUR PERIOD...BUT CONDITIONS BECOME LESS
CONDUCIVE BEYOND THAT TIME FRAME. NONETHELESS...TIDE LEVELS DUE TO
PERSISTENT ONSHORE FLOW WILL LIKELY INCREASE 1 FOOT ABOVE NORMAL
WITH SOME LOCALIZED UP TO 2 FEET ABOVE NORMAL ALONG EAST FACING
SHORES BY SUNDAY EVENING. 24/RR

&&

.DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT. MONITORING INVEST 92L.

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  70  87  68  88 /  50  50  30  20
BTR  72  88  69  90 /  50  50  30  30
ASD  74  89  72  90 /  40  50  30  50
MSY  77  90  77  90 /  40  50  30  50
GPT  76  87  73  89 /  40  50  30  50
PQL  73  88  71  90 /  30  50  30  50

&&

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

$$

24/RR
35







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