Severe Thunderstorm Warning 67, NWS New Orleans, LA

AREA FORECAST DISSCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
836 AM CDT FRI MAR 18 2016

...SOUNDING DISCUSSION...

THE ATMOSPHERE IS STILL ENERGETIC. INVERSION FROM THE SURFACE TO
950 MB (2000 FT) IS HELPING TO RETAIN MOISTURE NEAR THE SURFACE.
THIS STABLE LAYER SHOULD MIX OUT LATER THIS MORNING. PWAT VALUES
AT 1.39 INCHES ARE STILL WELL ABOVE CLIMATOLOGICAL AVERAGE.
ADDITIONALLY...FCST CAPE VALUES ARE +1800 J/KG SO THE BUOYANCY
NEEDED FOR STORMS REMAINS IN THE AREA. THE LIFTING MECHANISM WILL
COME FROM THE STATIONARY BOUNDARY THAT CURRENTLY CUTS ACROSS THE
REGION. SURFACE WINDS ARE SOUTHEASTERLY AT 15 KTS WHILE ABOVE THE
INVERSION WINDS ARE WESTERLY WITH A MAX WIND SPEED OF 110 KTS.
THESE FACTORS WILL HELP SET THE STAGE FOR MORE THUNDERSTORMS LATER
TODAY IN THE AFTERNOON HOURS.

DRJ

&&

.PREV DISCUSSION... /ISSUED 343 AM CDT FRI MAR 18 2016/

DISCUSSION...
ANOTHER SOMEWHAT COMPLEX FORECAST FOR TODAY WITH QUASI-STATIONARY
FRONT STILL DRAPED ACROSS THE AREA. EARLIER OUTFLOW BOUNDARY
SERVED AS A PSEUDO COLD FRONT AND RESULTED IN SIGNIFICANT COOLING
ACROSS THE AREA. TEMPERATURES HAVE ALREADY BEGUN RECOVERING SOUTH
AND WEST OF THE TIDAL LAKES...AS WELL AS ON THE MISSISSIPPI COAST
AND EXPECT TEMPS TO REMAIN STEADY OR RISE SLOWLY THROUGH THE PRE-
DAWN HOURS THIS MORNING.

STORMS OVER NORTHERN LOUISIANA AND CENTRAL MISSISSIPPI HAVE NOT
MADE MUCH SOUTHWARD PROGRESS THROUGH THE NIGHT AND THE IMPULSE
DRIVING THOSE STORMS SHOULD STAY TO THE NORTH OF THE LOCAL AREA.
THE PRIMARY FOCUS FOR CONVECTION OVER SOUTHEAST LOUISIANA AND
SOUTHERN MISSISSIPPI WILL CONTINUE TO BE THE OLD FRONTAL BOUNDARY
WHICH CONTINUES TO MEANDER AROUND THE REGION.

TIMING AND INTENSITY OF CONVECTION IS PROVING TO BE A TRICKY
FORECAST AGAIN TODAY. LATEST HRR SUGGESTS CONVECTIVE COVERAGE WILL
BEGIN INCREASING AROUND MID DAY AND THIS COINCIDES WITH A WEAK
MID LEVEL VORT MAX MOVING THROUGH THE AREA. COLD TEMPERATURES
ALOFT CONTINUE TO RESULT IN FAIRLY IMPRESSIVE MID LEVEL LAPSE
RATES. APPEARS THAT LAPSE RATES SHOULD BE SUFFICIENT TO SUPPORT A
FEW STRONG/SEVERE STORMS...WITH LARGE HAIL AND DAMAGING WIND
GUSTS ONCE AGAIN BEING THE PRIMARY CONCERNS.

ON TO RAINFALL...NEW RAINFALL OF 1 TO 2 INCHES WITH LOCALLY
HIGHER AMOUNTS STILL SEEMS REASONABLE. BIGGEST CONCERN IS THAT THE
CURRENT LOCATION OF THE STALLED BOUNDARY MAY ONCE AGAIN FOCUS THE
HEAVIEST RAINFALL OVER AREAS THAT REMAIN SATURATED. IN THESE
AREAS...RAINFALL WILL QUICKLY BE CONVERTED TO RUNOFF AND ANY HIGH
RAINFALL RATES COULD LEAD TO PONDING OF WATER IN LOW LYING AREAS
AND AREAS OF POOR DRAINAGE. IF STORMS REMAIN MORE CELLULAR IN
NATURE...COULD ALSO SEE A FEW STORMS MOVE OVER THE SAME AREAS AND
THIS COULD LEAD TO LOCALIZED FLASH FLOODING.

GOING INTO SATURDAY...UPPER LOW WILL MOVE TOWARD THE GREAT LAKES
REGION WITH AN UPPER TROUGH DIGGING INTO CENTRAL TEXAS. THIS WILL
FORCE A COLD FRONT THROUGH THE AREA DURING THE DAY SATURDAY AND
WILL PUT AN END TO THE RAINFALL. A MUCH COOLER AND DRIER CANADIAN
AIR MASS WILL BUILD INTO THE AREA BEHIND THE COLD FRONT. SUNDAY
AND MONDAY AFTERNOON HIGHS WILL GENERALLY TOP OUT IN THE LOW TO
MID 60S. COLDEST TEMPERATURES WILL OCCUR SUNDAY NIGHT INTO MONDAY
MORNING AS THE HIGH BECOMES MORE CENTERED OVER THE AREA. CLEAR
SKIES...LIGHT WINDS...AND DEWPOINTS IN THE UPPER 20S AND 30S WILL
ALLOW TEMPERATURES TO PLUMMET AFTER SUNSET AND WE SHOULD BE
LOOKING AT OUR COLDEST MORNING SINCE THE LAST WEEK OF FEBRUARY.
SOME ENSEMBLE MEMBERS DO SUGGEST FREEZING TEMPS FOR OUR TYPICALLY
COLDER SPOTS...BUT THINK THAT MAY BE A BIT OVERDONE. FOR NOW WILL
STICK WITH FORECAST TEMPS IN THE MID TO UPPER 30S FOR AREAS THAT
ARE GENERALLY ALONG/NORTH OF THE I-10/12 CORRIDOR.

ONCE THE HIGH BEGINS TO SHIFT EASTWARD ON TUESDAY...EXPECT A
GRADUAL WARMING TREND TO BEGIN. TEMPS WILL RETURN TO NEAR NORMAL
TUESDAY AND WEDNESDAY...AND WILL BE A FEW DEGREES ABOVE NORMAL BY
THURSDAY.

AVIATION...
CEILINGS SHOULD STAY BETWEEN BKN030-060 THROUGH THIS TAF CYCLE.
ANOTHER ROUND OF TS WILL BE AROUND MOST IF NOT ALL TERMINALS TODAY
AND WILL SHOW THIS AS AT LEAST VCTS. THIS ACTIVITY SHOULD START UP
DURING THE MORNING HOURS AND LAST THROUGHOUT THE DAY WITH A GRADUAL
DECAY DURING THE EVENING HOURS. WILL FRAME THE MORNING ACTIVITY WITH
A TIME FOR THE MORNING HOURS AS TEMPO OR PREVAILING DEPENDING ON
WHERE TS SHOULD BE MOST ABUNDANT.

MARINE...
THUNDERSTORMS WILL CONTINUE OVER THE COASTAL WATERS WITH SOME OF
THESE BECOMING SEVERE. A STRONG COLD FRONT IS EXPECTED TO MOVE
THROUGH THE COASTAL WATERS SATURDAY AFTERNOON AND EVENING.
ANTICIPATE SMALL CRAFT ADVISORY CONDITIONS BY LATE SATURDAY
AFTERNOON OR SATURDAY EVENING...CONTINUING THROUGH SUNDAY NIGHT
BEFORE EASING. A BRIEF BREAK IN THE ACTION FOR MONDAY AND TUESDAY
BEFORE MODERATE ONSHORE FLOW RETURNS.

DECISION SUPPORT...
DSS CODE....BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...MODERATE RIVER FLOODING.
             MARGINAL TO SLIGHT RISK OF SEVERE WEATHER.

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  76  56  62  40 /  80  60  40  10
BTR  78  60  65  42 /  80  70  40  10
ASD  76  62  69  44 /  80  70  60  10
MSY  78  62  68  48 /  80  70  60  10
GPT  74  64  69  44 /  80  70  60  20
PQL  75  62  70  45 /  80  70  60  20

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS LA
433 AM CDT FRI MAR 18 2016

GMZ530-532-534-536-538-550-552-555-557-570-572-575-577-LAZ034>037-
039-040-046>050-056>072-MSZ068>071-077-080>082-182145-
LAKE PONTCHARTRAIN AND LAKE MAUREPAS-MISSISSIPPI SOUND-
LAKE BORGNE-CHANDELEUR SOUND-BRETON SOUND-
COASTAL WATERS FROM PORT FOURCHON LA TO LOWER ATCHAFALAYA RIVER
LA OUT 20 NM-
COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER
TO PORT FOURCHON LOUISIANA OUT 20 NM-
COASTAL WATERS FROM BOOTHVILLE LA TO SOUTHWEST PASS OF THE
MISSISSIPPI RIVER OUT 20 NM-
COASTAL WATERS FROM PASCAGOULA MISSISSIPPI TO STAKE ISLAND OUT
20 NM-
COASTAL WATERS FROM PORT FOURCHON LOUISIANA TO LOWER ATCHAFALAYA
RIVER LA FROM 20 TO 60 NM-
COASTAL WATERS FROM SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO
PORT FOURCHON LOUISIANA FROM 20 TO 60 NM-
COASTAL WATERS FROM STAKE ISLAND LA TO SOUTHWEST PASS OF THE
MISSISSIPPI RIVER FROM 20 TO 60 NM-
COASTAL WATERS FROM PASCAGOULA MISSISSIPPI TO STAKE ISLAND
LOUISIANA OUT 20 TO 60 NM-POINTE COUPEE-WEST FELICIANA-
EAST FELICIANA-ST. HELENA-WASHINGTON-ST. TAMMANY-IBERVILLE-
WEST BATON ROUGE-EAST BATON ROUGE-ASCENSION-LIVINGSTON-ASSUMPTION-
ST. JAMES-ST. JOHN THE BAPTIST-UPPER LAFOURCHE-ST. CHARLES-
UPPER JEFFERSON-ORLEANS-UPPER PLAQUEMINES-UPPER ST. BERNARD-
UPPER TERREBONNE-LOWER TERREBONNE-LOWER LAFOURCHE-LOWER JEFFERSON-
LOWER PLAQUEMINES-LOWER ST. BERNARD-NORTHERN TANGIPAHOA-
SOUTHERN TANGIPAHOA-WILKINSON-AMITE-PIKE-WALTHALL-PEARL RIVER-
HANCOCK-HARRISON-JACKSON-
433 AM CDT FRI MAR 18 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST
LOUISIANA...SOUTH MISSISSIPPI AND THE ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE WESTERN
HALF OF THE AREA AND A MARGINAL RISK FOR THE REMAINING EASTERN
HALF THROUGH TONIGHT. THE MAIN HAZARDS EXPECTED WILL BE LARGE
HAIL AND DAMAGING WINDS.

1 TO 3 INCHES OF RAINFALL MAY OCCUR WITH THUNDERSTORMS THROUGH
TONIGHT. IF THIS AMOUNT OF RAIN FALLS WITHIN A SHORT TIME ON
SATURATED GROUND...IT MAY RESULT IN LOCALIZED FLOODING.

NUMEROUS RIVERS ARE IN FLOOD. FOR DETAILED INFORMATION CONSULT
THE LATEST FLOOD WARNINGS AND FLOOD STATEMENTS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

A STRONG COLD FRONT WILL MOVE THROUGH THE AREA SATURDAY MORNING
AND THROUGH THE COASTAL WATERS SATURDAY AFTERNOON AND EVENING. THE
FRONT WILL BE FOLLOWED BY STRONG NORTHERLY WINDS THAT WILL CREATE
HAZARDOUS CONDITIONS FOR SMALL CRAFT SATURDAY NIGHT THROUGH SUNDAY
NIGHT. SMALL CRAFT ADVISORIES MAY BE ISSUED LATER TODAY AS TIMING
OF THIS EVENT IS BETTER ESTABLISHED.

SCATTERED FROST WILL BE POSSIBLE OVER SOUTHWEST MISSISSIPPI AND
ADJACENT PORTIONS OF SOUTHEAST LOUISIANA MONDAY MORNING AS
OVERNIGHT LOW TEMPERATURES FALL INTO THE MIDDLE 30S.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1032 AM CDT FRI MAR 18 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1000 AM     HAIL             3 N HOUMA               29.62N 90.71W
03/18/2016  E1.00 INCH       TERREBONNE         LA   PUBLIC

            REPORT OF QUARTER SIZED HAIL. TIME OF EVENT ESTIMATED BY
            RADAR.

&&

FREVITTE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1042 AM CDT FRI MAR 18 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0958 AM     HAIL             GRAY                    29.68N 90.78W
03/18/2016  E1.25 INCH       TERREBONNE         LA   BROADCAST MEDIA

            PUBLIC REPORT RELAYED BY THE MEDIA

1008 AM     HAIL             5 SE THIBODAUX          29.74N 90.76W
03/18/2016  E1.00 INCH       LAFOURCHE          LA   TRAINED SPOTTER

1017 AM     HAIL             1 N RACELAND            29.73N 90.60W
03/18/2016  E1.75 INCH       LAFOURCHE          LA   TRAINED SPOTTER

            GOLFBALL HAIL REPORTED ON LOUISIANA HIGHWAY 1 JUST NORTH
            OF RACELAND.

1032 AM     HAIL             GRAY                    29.68N 90.78W
03/18/2016  E1.25 INCH       TERREBONNE         LA   PUBLIC

            PUBLIC REPORT OF HALF DOLLAR HAIL.

&&

FREVITTE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1051 AM CDT FRI MAR 18 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1014 AM     HAIL             4 ESE THIBODAUX         29.77N 90.76W
03/18/2016  E2.00 INCH       LAFOURCHE          LA   PUBLIC

            PUBLIC REPORT AND PHOTO VIA SOCIAL MEDIA

&&

FREVITTE