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

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000
FXUS64 KLIX 271311
AFDLIX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
811 AM CDT WED MAY 27 2015

...SOUNDING DISCUSSION...

A VERY SHALLOW SATURATED LAYER BELOW THE TOP OF THE TEMPERATURE
INVERSION ALLOWED PATCHY FOG TO FORM IN A FEW SPOTS WITH REDUCED
VISIBLITY NOTED AT BOGALUSA...MCCOMB AND PASCAGOULA. THIS
TEMPERATURE INVERSION IS ALSO THE CAP IN PLACE WITH INHIBITION
CALCULATED AT ABOUT 150 J/KG. WE CONTINUE TO WATCH THE LINE OF
THUNDERSTORMS OVER CENTRAL LOUISIANA THAT IS MARCHING TOWARD
SOUTHEAST LOUISIANA AND SOUTHWEST MISSISSIPPI. PLENTY OF CAPE
AROUND 1500 J/KG FOR THIS LINE TO TAP INTO...BUT 500MB WINDS ARE
RATHER WEAK AT JUST 15 KNOTS. RADAR SHOW A DOWNWARD TREND IN
REFLECTIVITY VALUES SO IF LINE CONTINUES TO HOLD
TOGETHER...STRAIGHT LINE WINDS WOULD BE THE MAIN CONCERN. THERE IS
QUITE A BIT OF MOISTURE UP TO 15000 FEET ABOVE WHICH THERE IS
SIGNIFICANT DRYING. THIS DRIER AIR WOULD BE WHAT COULD CAUSE
DOWNBURST WINDS WITH A DOWNDRAFT CAPE AT 1260 J/KG...WHICH IS
ABOVE THE 950 J/KG THRESHOLD. HOWEVER...STRONGEST GUST OF 38 KNOTS
WAS OBSERVED AT 1201Z AT LAKE CHARLES AND 31 KNOTS AROUND 1300Z AT
JENNINGS.

AS MENTIONED...QUITE A BIT OF MOISTURE AND PRECIPITABLE WATER
VALUE OF 1.66 INCHES IS ABOVE NORMAL FOR THIS TIME OF YEAR. RADAR
ESTIMATES FROM KLCH WSR-88D HAVE SHOWN WIDESPREAD 1-2 INCHES WITH
THE INITIAL LINE OF THUNDERSTORMS AND AFTER THE STRATIFORM RAIN
FALLS BEHIND THE MAIN LINE...2-4 INCHES STORM TOTAL. WITH WEAK
UPPER LEVEL WINDS AS DISCUSSED ABOVE...MAY HAVE TO WATCH RAIN
RATES FOR FLASH FLOODING. RECENT MESOSCALE PRECIPITATION
DISCUSSION ISSUED BY WPC ALSO HIGHLIGHTS THIS MENTIONING POTENTIAL
RAIN RATES COULD EXCEED FLASH FLOOD GUIDANCE.

12Z BALLOON INFO: NO ISSUES WITH THE FLIGHT THIS MORNING THAT
ASCENDED TO A HEIGHT OF 19.8 MILES ABOVE THE GROUND BEFORE
BURSTING JUST NORTHWEST OF KILN 22 MILES DOWNRANGE FROM THE
OFFICE. THE ASCENT LASTED 107 INUTES.

ANSORGE

&&

.PREV DISCUSSION... /ISSUED 308 AM CDT WED MAY 27 2015/

DISCUSSION...QUIET NIGHT OVER THE CWA BUT WE CONTINUE TO WATCH THE
ACTIVITY WORKING SE OUT OF NERN TX AND INTO WRN LA. THIS SHOULD
IMPACT THE REGION LATER TODAY. THIS COMPLEX APPEARS TO BE ASSOCIATED
WITH A WEAK IMPULSE AND INCREASED LIFT STREAMING IN FROM THE PAC
OVER THE DESERT SW.

TODAY SHOULD BE FAR MORE ACTIVE THAN YESTERDAY. WE HAVE NOW
RECOVERED AND ABUNDANT MOISTURE IS IN PLACE. COMBINE THAT WITH
DAYTIME HEATING TODAY...THE COMPLEX MOVING IN FROM THE NW...WEAK
TROUGHING ALOFT...AND THE INCREASE IN LIFT WORKING IN AND WE
SHOULD SEE SCT TO NUM SHRA AND TSRA WITH CONVECTION BEGINNING TO
DEVELOP POSSIBLY AS EARLY AS LATE MORNING. CONVECTION WILL
CONTINUE TO INCREASE COVERAGE AS ADDED INFLUENCE FROM THE
SEA/LAKE BREEZE KICKS IN. GREATEST CONCENTRATION OF STORMS LOOKS
LIKE IT COULD BE JUST SOUTH OF THE SWRN MS COUNTIES AND NORTH OF A
LINE FROM HUM TO NBG. AS FOR STRONG TO SVR STORMS...THERE WILL BE
SUFFICIENT INSTABILITY IN PLACE ALONG WITH STEEP MID LVL LAPSE
RATES AND THIS SHOULD GET A FEW STORMS TO OVERACHIEVE. LACK OF
SIGNIFICANT SHEAR AND MID LVL FLOW WILL KEEP ORGANIZED SVR WEATHER
FROM DEVELOPING. MAIN CONCERN FROM STORMS WILL STRONG TO DAMAGING
STRAIGHTLINE WINDS...FREQUENT LIGHTNING...AND TORRENTIAL
DOWNPOURS.

AS HAS BEEN MENTIONED CONVECTIVE COVERAGE SHOULD BE A LITTLE LESS ON
THU AS S/W RIDGING MOVES IN. GIVEN THAT...AFTN HEATING AND ONLY WEAK
SUBSIDENCE ALOFT SHOULD NOT HOLD CONVECTION AT BAY ALL DAY. ISLTD
TO SCT STORMS WILL STILL BE POSSIBLE DURING THE AFTERNOON THU. AS
WE HEAD INTO FRI AND THE WEEKEND THINGS WILL BECOME MORE
SUMMERLIKE AS CONVECTION WILL BE DRIVEN BY DIURNAL INFLUENCES.
AFTN CONVECTION WILL OCCUR OVER LAND AREAS AND THEN ISLTD ACTIVITY
WILL LIKELY DRIFT TOWARDS THE MARINE ZONES. /CAB/

AVIATION... TAFS ARE STILL CONTINGENT ON DEVELOPMENTS WITH SQUALL
LINE ADVANCING OUT OF NE TEXAS EARLY THIS MORNING AND INTERACTING
WITH GULF BREEZE CONVERGENCE BOUNDARIES AHEAD OF SQUALL. INDICATING
TEMPO GROUPS GENERALLY BETWEEN 17Z-21Z THAT MAY NEED TEMPORAL
ADJUSTMENTS BASED ON RADAR TRENDS LATER THIS MORNING.
OTHERWISE...VFR CONDITIONS ARE EXPECTED OUTSIDE PERIODS OF
CONVECTION.

MEFFER/RR

MARINE... BERMUDA HIGH EXTENDS ACROSS THE ENTIRE GULF OF MEXICO AND
WILL REMAIN IN PLACE THROUGH THE REST OF THE WEEK. THIS WILL KEEP
SOUTHEAST WINDS GENERALLY IN THE 8 TO 14 KNOT RANGE DURING THIS
PERIOD WITH SEAS 1 TO 3 FEET. AN APPROACHING COLD FRONT MID WEEKEND
WILL BREAK DOWN THE SURFACE HIGH AND LEAD TO WEAK PRESSURE FIELD
OVER THE AREA. THUS WINDS AND SEAS WILL RELAX SUNDAY THRU EARLY NEXT
WEEK WITH WINDS UNDER 10 KTS AND SEAS LESS THAN A FOOT.

MEFFER

DECISION SUPPORT...
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.

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 RISK SVR AND/OR DIRECT
         TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  86  70  85  69 /  50  30  50  20
BTR  87  71  86  71 /  60  30  50  20
ASD  86  72  85  72 /  60  30  40  20
MSY  86  74  86  74 /  50  20  40  20
GPT  84  74  85  74 /  60  30  40  20
PQL  84  71  85  71 /  60  30  40  20

&&

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

$$



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