Severe Thunderstorm Warning 46, NWS New Orleans, LA

AREA FORECAST DISSCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
824 AM CDT THU MAR 17 2016

...SOUNDING DISCUSSION...

SOUNDING LOOKS PRETTY ACTIVE THIS MORNING AND THE AIR COLUMN
ABOVE IS VERY MOIST. THE SATURATED LAYER BELOW 1000 FT SHOULD MIX
OUT BY LATER THIS MORNING. THE PWAT VALUE OF 1.38 INCHES PUTS US
IN THE 90 PERCENTILE RANGE FOR THIS TIME OF YEAR. CAPE VALUES ARE
3000-2000 J/KG WHICH IS FAIRLY HIGH AND CONDUCIVE OF STRONG
UPDRAFTS. THE FZL LEVEL IS BELOW 13 KFT AND WITH LAPSE RATES
APPROX. 7 C/KM...PEA TO QUARTER SIZED HAIL COULD BE ASSOCIATED
WITH THE FORECASTED ISOLATED THUNDERSTORMS. WINDS ARE WSW AT 45
KTS AT 500 MB (19 KFT) AND 125 KTS AT 200 MB (40 KFT). THESE MID
AND UPPER LEVEL WINDS WILL ALSO ASSIST WITH THE SEVERITY OF THE
STORMS LATER TODAY.

DRJ

&&

.PREV DISCUSSION... /ISSUED 359 AM CDT THU MAR 17 2016/

DISCUSSION...
ANOTHER ACTIVE WEATHER PERIOD WILL BEGIN TODAY. CURRENT SURFACE
ANALYSIS INDICATES A QUASI-STATIONARY BOUNDARY IS CURRENTLY
STRETCHED ROUGHLY ALONG THE LA/MS BORDER AND IT WILL MEANDER
AROUND THE AREA FOR THE NEXT COUPLE DAYS SERVING AS A FOCUS FOR
CONVECTION UNTIL IT IS FINALLY PUSHED OFF SHORE AS A STRONGER
FRONT MOVES THROUGH THE AREA SATURDAY.

THERE ARE A COUPLE POTENTIAL CONCERNS WITH THE EXPECTED
CONVECTION OVER THE NEXT COUPLE DAYS. FIRST...RAINFALL. AREA
AVERAGE RAINFALL IS GENERALLY EXPECTED TO BE IN THE 1 TO 2.5 INCH
RANGE...BUT AS IS USUALLY THE CASE WITH CONVECTIVE STORMS LOCALLY
HIGHER AMOUNTS WILL BE POSSIBLE. MUCH OF THE RAIN WILL BE
IMMEDIATELY CONVERTED TO RUNOFF IN AREAS WHERE THE GROUND REMAINS
SATURATED FOLLOWING LAST WEEK/S HEAVY RAINFALL. IF THE RAIN FALLS
TOO QUICKLY OVER THESE AREAS...IT COULD RESULT IN ADDITIONAL
FLOODING OR EXACERBATE ONGOING FLOODING IN AREAS WHERE THE WATER
HAS NOT YET RECEDED.

SECOND CONCERN WILL BE POTENTIAL FOR ISOLATED SEVERE THUNDERSTORMS
PRIMARILY THIS AFTERNOON. DESPITE WEAK FORCING IN THE AREA...THE
STALLED BOUNDARY WILL SERVE AS A FOCUS AND VERTICAL WIND SHEAR
APPEARS ENOUGH TO SUPPORT A FEW STRONG/SEVERE STORMS. WITH DECENT
MID LEVEL LAPSE RATES...IT LOOKS LIKE HAIL WILL BE THE PRIMARY
THREAT. SPC HAS INTRODUCED A SLIGHT RISK OF SEVERE WEATHER FOR
AREAS GENERALLY ALONG/NORTH OF THE I-10/12 CORRIDOR AND A MARGINAL
RISK FOR PARTS OF THE SOUTH SHORE. THIS IS ROUGHLY IN THE VICINITY
OF THE STALLED FRONTAL BOUNDARY...WHERE MOST OF THE CONVECTION
SHOULD BE FOCUSED TODAY.

FRIDAY...THE FRONT CONTINUES TO MEANDER AROUND THE AREA WITH THE
SAME CONCERNS AS TODAY...THOUGH SEVERE WEATHER LOOKS A BIT LESS
LIKELY AS VERTICAL WIND SHEAR IS EXPECTED TO DECREASE. CAN/T RULE
OUT ONE OR TWO STRONG/SEVERE STORMS...THOUGH...AND SPC IS
INDICATING A MARGINAL RISK ACROSS ALL OF SE LA AND S MS.

BY SATURDAY...AN UPPER LOW MOVING INTO THE MIDDLE/UPPER
MISSISSIPPI VALLEY WILL FORCE A STRONGER COLD FRONT THROUGH THE
AREA PUTTING AN END TO THE RAIN AFTER IT PASSES. IN ALL...STORM
TOTAL RAINFALL IS NOT EXPECTED TO CAUSE ANY SIGNIFICANT ISSUES AS
THE HIGHEST TOTALS ARE CURRENTLY EXPECTED ACROSS THE MS COASTAL
COUNTIES WESTWARD THROUGH THE SOUTH SHORE AREA. HOWEVER...AS
PREVIOUSLY MENTIONED...IF THE RAINFALL SHIFTS A BIT TO THE
NORTHWEST...FLOODING AND FLASH FLOODING CONCERNS WOULD BE
GREATER.

FOLLOWING SATURDAY/S FRONTAL PASSAGE IT LOOKS LIKE WE/LL SEE ONE
LAST GASP OF WINTER-LIKE MORNING TEMPERATURES AS A COLD CANADIAN
HIGH PRESSURE SETTLES OVER THE AREA. THE COLDEST MORNING LOOKS TO
BE MONDAY WITH TEMPS FALLING INTO THE MID TO UPPER 30S ALONG/NORTH
OF THE I-10/12 CORRIDOR AND INTO THE 40S SOUTH OF THE TIDAL LAKES.
NORTHERNMOST AREAS MAY EVEN SEE SOME FROST DURING THE EARLY
MORNING HOURS. AFTERNOON TEMPERATURES IN THE 60S CAN BE EXPECTED
SUNDAY AND MONDAY BEFORE THE HIGH SHIFTS EASTWARD AND SETS OFF A
WARMING TREND.

AVIATION...
VARIABLE CONDITIONS AROUND THE AREA THIS MORNING WITH SOME TERMINALS
VFR AND OTHERS MVFR OR IFR. EXPECT CONDITIONS TO CONSOLIDATE IN THE
LOW END OF MVFR WITH MOST CEILINGS FL010-015 PRIOR TO SUNRISE.
CANNOT RULE OUT A FEW IN THE IFR RANGE THROUGH ABOUT 14Z BEFORE
THINGS GENERALLY IMPROVE TO VFR BY LATE MORNING. THERE WILL BE A FEW
THUNDERSTORMS ONCE CONVECTIVE TEMPERATURES ARE REACHED PRIOR TO 17Z.
MOST LIKELY AREAS FOR THE CONVECTION WILL BE NEAR THE INTERSTATE
10/12 CORRIDOR. THIS WOULD INCLUDE ALL TERMINALS EXCEPT KHUM AND
KMCB. WILL CARRY VCTS IN THOSE TERMINALS FOR THE AFTERNOON
HOURS...AND AMEND TO PREVAILING WHERE NECESSARY ONCE STORMS DEVELOP.
THREAT OF CONVECTION SHOULD EASE DURING THE OVERNIGHT HOURS...WITH
MOST AREAS VFR 00Z-08Z. COULD SEE SOME DEGRADATION OF CONDITIONS
BEYOND 08Z.

MARINE...
RELATIVELY QUIET CONDITIONS ON THE COASTAL WATERS FOR ABOUT THE NEXT
48 HOURS...UNTIL THE PASSAGE OF A STRONG COLD FRONT DURING THE DAY
SATURDAY. 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.

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  77  59  73  57 /  60  60  60  50
BTR  80  64  75  60 /  60  50  60  50
ASD  79  64  73  61 /  60  50  70  60
MSY  79  65  75  62 /  60  50  70  60
GPT  76  64  73  61 /  60  60  70  60
PQL  77  61  74  61 /  60  60  70  60

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS LA
417 AM CDT THU MAR 17 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>082-172130-
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-
417 AM CDT THU MAR 17 2016

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

.DAY ONE...TODAY AND TONIGHT

SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND TONIGHT
ACROSS SOUTHEAST LOUISIANA AND SOUTHERN MISSISSIPPI NEAR A
STATIONARY FRONT. A FEW THUNDERSTORMS COULD BE SEVERE ALONG AND
NORTH OF THE INTERSTATE 10 AND 12 CORRIDOR. THERE IS A SLIGHT RISK
OF SEVERE THUNDERSTORMS IN THIS AREA. THE MAIN THREAT WITH ANY
SEVERE THUNDERSTORMS WOULD BE LARGE HAIL. IN ADDITION...GUSTY
WINDS TO 40 MPH...OCCASIONAL LIGHTNING AND BRIEF HEAVY RAIN MAY
RESULT.

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

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

RIVER FLOODING IS EXPECTED TO CONTINUE. FOR DETAILED INFORMATION
CONSULT THE LATEST FLOOD STATEMENTS AND WARNINGS.

THUNDERSTORMS WILL BE POSSIBLE FRIDAY AND SATURDAY. A FEW STORMS
COULD BE STRONG TO SEVERE FRIDAY AFTERNOON AND FRIDAY NIGHT WITH
THE POTENTIAL FOR LARGE HAIL AND STRONG GUSTY WINDS AS WELL AS
BRIEF HEAVY RAINFALL. DEPENDING ON WHERE THE HEAVIER RAINS
ALIGN...SOME OF THE FLOOD AREAS MAY BE EXPANDED OR EXTENDED FOR
LONGER DURATION.

A STRONG COLD FRONT IS EXPECTED TO BE FOLLOWED BY STRONG
NORTHERLY WINDS THAT WILL CREATE HAZARDOUS WAVE CONDITIONS FOR
SMALL CRAFT SATURDAY NIGHT INTO SUNDAY.

SCATTERED FROST WILL BE POSSIBLE OVER SOUTHWEST MISSISSIPPI AND
PORTIONS OF SOUTHEAST LOUISIANA NORTH OF INTERSTATE 12 MONDAY
MORNING AS OVERNIGHT LOW TEMPERATURES FALL INTO THE MIDDLE 30S.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NO LONGER REQUIRED AT THIS TIME BUT RIVER
LEVEL READINGS FROM FLOOD AREAS ARE STILL REQUESTED.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
853 AM CDT THU MAR 17 2016

LAZ034>037-039-040-046>050-071-072-MSZ068>071-077-080>082-171445-
EAST FELICIANA-POINTE COUPEE-ST. TAMMANY-EAST BATON
ROUGE-LIVINGSTON-WEST FELICIANA-SOUTHERN TANGIPAHOA-NORTHERN
TANGIPAHOA-IBERVILLE-WASHINGTON-ST. HELENA-WEST BATON
ROUGE-ASCENSION-WALTHALL-PEARL
RIVER-AMITE-WILKINSON-HARRISON-JACKSON-PIKE-HANCOCK-
853 AM CDT THU MAR 17 2016

...LOW CLOUDS AND FOG OVER EAST CENTRAL LOUISIANA AND SOUTHERN
   MISSISSIPPI...

WITH A STATIONARY FRONT EXTENDING FRONT FROM CENTRAL LOUISIANA TO
SOUTHEAST MISSISSIPPI AND SATURATED AIR MASS JUST OF THIS
FRONT...LOW CLOUDS AND FOG HAVE DEVELOPED OVER THE EAST CENTRAL
LOUISIANA AND SOUTHERN MISSISSIPPI THIS MORNING.

MOST AIRPORTS REPORTED VISIBILITY READINGS BETWEEN 1 AND 2
MILES...BUT A BATON ROUGE...BOGALUSA AND SOUTHERN HANCOCK REPORTED
VISIBILITY VALUES AROUND A QUARTER OF MILE DUE TO FOG. THIS FOG WILL
SLOWLY LIFT AND DISSIPATE BY 930 AM.

LAT...LON 3043 8893 3042 8901 3040 8886 3033 8938
      3031 8933 3030 8933 3030 8934 3039 9020
      3028 9037 3026 9159 3098 9180 3102 9158
      3122 9158 3136 9130 3135 9011 3100 8983
      3101 8935 3065 8934 3074 8841 3035 8839
TIME...MOT...LOC 1342Z 240DEG 49KT 3071 9076

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
955 AM CDT THU MAR 17 2016

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

0945 AM     HAIL             10 NNW TYLERTOWN        31.25N 90.21W
03/17/2016  E1.50 INCH       WALTHALL           MS   PUBLIC

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1034 AM CDT THU MAR 17 2016

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

0950 AM     HAIL             8 NNW SALEM             31.34N 90.17W
03/17/2016  E2.75 INCH       WALTHALL           MS   PUBLIC

&&