SEVERE WEATHER THREAT: 11/22 - 11/23

043
FLUS44 KLIX 221123
HWOLIX

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS LA
523 AM CST SAT NOV 22 2014

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>082-222330-
LAKE PONTCHARTRAIN AND LAKE MAUREPAS-MISSISSIPPI SOUND-
LAKE BORGNE-CHANDELEUR SOUND-BRETON SOUND-
COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER OUT
20 NM-
COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER
TO PORT FOURCHON OUT 20 NM-
COASTAL WATERS FROM BOOTHVILLE LA TO THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER OUT 20 NM-
COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA OUT 20 NM-
COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER FROM
20 TO 60 NM-
COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER
TO PORT FOURCHON FROM 20 TO 60 NM-
COASTAL WATERS FROM STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER FROM 20 TO 60 NM-
COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 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-
523 AM CST SAT NOV 22 2014

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

.DAY ONE...TODAY AND TONIGHT

A VIGOROUS STORM SYSTEM WILL BRING A MULTITUDE OF IMPACTS TO THE
REGION THIS WEEKEND. SEVERE WEATHER...HEAVY RAIN...COASTAL
FLOODING...AND MARINE ISSUES ARE ALL HIGHLIGHTED.

THE MAIN CONCERN WITH THIS SYSTEM WILL BE THE THREAT OF STRONG
AND SEVERE THUNDERSTORMS. THE STORM PREDICTION CENTER HAS PLACED
MOST OF THE OUTLOOK AREA UNDER AN ENHANCED RISK FOR SEVERE
WEATHER. THE MAIN TIME FRAME WILL BE TONIGHT AND THROUGH SUNDAY
MORNING WITH SEVERE WEATHER POSSIBLE ACROSS THE ENTIRE REGION BUT
THE AREA WITH THE GREATEST THREAT FOR SEVERE STORMS WILL BE ALONG
AND EAST OF A LINE FROM NEAR BATON ROUGE TO NEAR MCCOMB. ALL MODES
OF SEVERE WEATHER WILL BE POSSIBLE...HOWEVER THE MAIN THREATS WILL
BE DAMAGING THUNDERSTORM WINDS AND ISOLATED TORNADOES.

IN ADDITION TO THE SEVERE THREAT HEAVY RAINFALL COULD BECOME AN
ISSUE TOO. MULTIPLE ROUNDS OF MODERATE TO HEAVY RAIN COULD
DEVELOP WITH THE FIRST BATCH OF RAIN POSSIBLE SATURDAY AFTERNOON
AND EVENING WITH THE WARM FRONT MOVING NORTH. WIDESPREAD 2 TO 3
INCHES OF RAIN ARE ANTICIPATED WITH LOCALLY HIGHER AMOUNTS
POSSIBLE THROUGH THE WEEKEND.

AS THIS SYSTEM CONTINUES TO DEVELOP AND MOVE INTO THE MID AND
LOWER MISSISSIPPI VALLEY WINDS WILL INCREASE OVER THE COASTAL
WATERS. SMALL CRAFT ADVISORIES ARE IN EFFECT FOR ALL OF THE
COASTAL WATERS. STRONG EAST WINDS NEAR 20 KNOTS WITH GUSTS UP TO
30 KNOTS ALONG WITH ROUGH SEAS CAN BE EXPECTED.

LAST BUT NOT LEAST...THE STRONG ONSHORE EASTERLY FLOW WILL PRODUCE
HIGHER THAN NORMAL TIDES AND A POTENTIAL COASTAL FLOOD THREAT
FROM THIS AFTERNOON THROUGH EARLY SUNDAY MORNING. A COASTAL
FLOOD ADVISORY IS IN EFFECT FOR THIS TIME PERIOD FOR THE EAST
FACING SHORES FROM BAY ST LOUIS MISSISSIPPI TO THE MOUTH OF THE
MISSISSIPPI RIVER...INCLUDING LAKE BORGNE... THE RIGOLETS AND CHEF
MENTEUR PASS. TIDES ARE EXPECTED TO BE 1 TO 2 FEET ABOVE NORMAL
WHICH MAY RESULT IN MINOR FLOODING OF ACCESS AREAS NEAR THE COAST
OUTSIDE THE HURRICANE LEVEE PROTECTION SYSTEM.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THE STRONG WINDS WILL CONTINUE OVER THE COASTAL WATERS THROUGH THE
REST OF THE WEEKEND WITH SMALL CRAFT ADVISORY CONDITIONS EXPECTED
OVER ALL OF THE COASTAL WATERS...INCLUDING THE SOUNDS AND TIDAL
LAKES. WINDS MAY TEMPORARILY SLACK OFF SUNDAY NIGHT BUT AS A COLD
FRONT MOVES THROUGH MONDAY AND WINDS VEER AROUND TO THE NORTHWEST
THEY WILL LIKELY PICK BACK UP TO AROUND 20 KNOTS WITH HIGHER
GUSTS.

.SPOTTER INFORMATION STATEMENT...

THE ACTIVATION OF STORM SPOTTERS...AND EMERGENCY MANAGEMENT
PERSONNEL IN SUPPORT OF SEVERE WEATHER OPERATIONS MAY BE NEEDED
FOR PORTIONS OF THE REGION SATURDAY NIGHT THROUGH SUNDAY MORNING.
OZONE AMATEUR RADIO CLUB...W5SLA...WILL BE ACTIVATED SATURDAY
EVENING THROUGH SUNDAY MORNING.

$$

CAB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOBILE AL
503 AM CST SAT NOV 22 2014

[SUNDAY AND MONDAY]...A POTENT NEGATIVELY TILTED UPPER SHORTWAVE
MOVING OVER THE ARKLATEX REGION SUNDAY MORNING WILL LIFT
NORTHEAST THROUGHOUT THE DAY. AN AREA OF SURFACE LOW PRESSURE
OVER OKLAHOMA WILL ALSO LIFT NORTHEAST AND STRENGTHEN...REACHING THE
GREAT LAKES REGION BY SUNDAY NIGHT. AN ASSOCIATED WARM FRONT IS
EXPECTED TO BE JUST SOUTH OF THE NORTHERN GULF COAST EARLY SUNDAY
MORNING...AND THEN ADVANCE RAPIDLY NORTHWARD ACROSS THE FORECAST
AREA THROUGH NOON SUNDAY. PLENTY OF MOISTURE WILL BE AVAILABLE TO
FEED INTO THIS NEXT WEATHER SYSTEM....WITH 850 MB DEWPOINTS RANGING
FROM 12C TO 14C AND SURFACE DEWPOINTS RANGING FROM 63F TO 68F ACROSS
THE FORECAST AREA.

THE UPPER LEVEL SYSTEM WILL HAVE A 100 KNOT JET STREAK AT 300 MB
OVER MISSISSIPPI SUNDAY MORNING...WITH MODERATE DIFFLUENCE ALOFT IN
THE RIGHT ENTRANCE REGION OVER THE FORECAST AREA. THE 850 MB JET
WILL MAXIMIZE SUNDAY MORNING OVER THE FORECAST AREA. BOTH THE 00Z
GFS AND ECMWF MODELS HAVE AN 850 MB JET OF 50 TO 55 KNOTS...WHILE
THE 06Z NAM12 HAS A 850 MB JET OF 60 TO 70 KNOTS.

STRONG DYNAMICS WILL ACCOMPANY THIS SYSTEM AND LOW LEVEL SHEAR WILL
BE EXTREMELY HIGH. BOTH THE 00Z ECMWF AND GFS MODELS ARE INDICATING
0-1KM HELICITY VALUES OF 300 TO 500 M2/S2 ALONG AND NORTH OF I-10
SUNDAY MORNING...WHILE THE NAM12 COMES IN WITH A STAGGERING 0-1KM
HELICITY VALUES OF 650 M2/S2 BY LATE SUNDAY MORNING.

INSTABILITY CONTINUES TO BE LOW WITH MLCAPES LESS THAN 500 J/KG
ACROSS MUCH OF THE FORECAST AREA. HOWEVER...WITH THE SYSTEM NOW
SLIGHTLY SLOWER...THE FOCUS FOR POTENTIALLY HIGHER MLCAPES NEAR 1000
J/KG COULD OCCUR SOUTH OF THE ADVANCING WARM FRONT AIDED BY DAYTIME
HEATING. THIS ENVIRONMENT WILL SUPPORT ROTATING THUNDERSTORM
UPDRAFTS WITH THE POTENTIAL FOR STRONG TO SEVERE STORMS WITH
ISOLATED TORNADOES AND DAMAGING STRAIGHT-LINED WINDS. IF ANY
TORNADOES DO FORM WE WOULD EXPECT FAST MOVING EF-0 AND EF-1
TORNADOES. A SIGNIFICANT TORNADO IN THE EF-2 CATEGORY IS NOT OUT OF
THE QUESTION ALONG OR JUST NORTH OF I-10 SUNDAY MORNING.

STRONG DEEP LAYER WINDS WILL RESULT IN STORMS MOVING TOWARD THE
NORTHEAST AT 40 TO 50 MPH...AND ANY SEVERE WEATHER THREATS WILL
LIKELY HAPPEN VERY QUICKLY IF A WARNING IS ISSUED. STAY TUNED TO
FURTHER DEVELOPMENTS AND INFORMATION AS THEY BECOME AVAILABLE.

THE BULK OF THE RAINFALL WILL BE ASSOCIATED WITH THE MAIN SQUALL
LINE AS IT MOVES FROM SOUTHWEST TO NORTHEAST ACROSS THE FORECAST
AREA SUNDAY MORNING. WIDESPREAD RAINFALL AMOUNTS WILL RANGE FROM 2
TO 3 INCHES...WITH LOCALIZED HIGHER AMOUNTS OF 4 TO 6 INCHES
POSSIBLE...ESPECIALLY ACROSS COASTAL AL/NW FL. DRY ANTECEDENT
CONDITIONS WILL LIKELY LIMIT THE THREAT OF FLASH FLOODING AND RIVER
FLOODING AS MANY RIVER STREAM FLOWS ARE AT OR BELOW NORMAL. THE MAIN
THREAT AT THIS TIME APPEARS TO BE URBAN AND SMALL STREAM FLOODING...
AS WELL AS LOCALIZED FLASH FLOODING IN URBAN AREAS...ESPECIALLY
ALONG THE I-10 CORRIDOR.

Another graphic...

A quick note ... they added a significant hail corridor for today. Storms are starting to ramp up outside but near the current SPC threat areas including a special marine warning off the coast of TX.

Also of note is freezing rain reports up north. Yuck!

SPC has taken out the "Enhanced" risk on the new Day 2 outlook

The greatest instability remains in south Texas along the Rio Grande. So far, not much instability across southeast Texas.