Wednesday, August 29, 2012

Daily Weather Briefing for 08-29-2012


Here is the forecast for the rest of the week and a look at what Isaac is up to this morning...


Today: A chance of showers, with thunderstorms also possible after 9am. Mostly cloudy, with a high near 84. Calm wind. Chance of precipitation is 40%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.


Hazardous Weather Outlook: SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE LIKELY ACROSS THE AREA TODAY AND TONIGHT WITH THE BEST COVERAGE EXPECTED SOUTH OF INTERSTATE 40. THE BIGGEST THREAT WITH THESE STORMS WILL BE CLOUD TO GROUND LIGHTNING AND PERIODS OF HEAVY RAINFALL THAT COULD PRODUCE LOCALIZED URBAN FLOODING ACROSS POOR DRAINAGE AND LOW

LYING AREAS.

Tonight: A chance of showers and thunderstorms. Patchy fog after 1am. Otherwise, mostly cloudy, with a low around 62. Calm wind. Chance of precipitation is 40%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.


Thursday: A chance of showers and thunderstorms. Areas of fog before 8am. Otherwise, mostly cloudy, with a high near 83. Light and variable wind. Chance of precipitation is 40%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.


Thursday Night: A chance of showers and thunderstorms, mainly before 9pm. Mostly cloudy, with a low around 64. Calm wind. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.


Friday: A chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 83. Calm wind. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.


Friday Night: A chance of showers and thunderstorms, mainly before midnight. Mostly cloudy, with a low around 64. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.


Tropical Outlook:


BULLETIN

HURRICANE ISAAC ADVISORY NUMBER  33
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL092012
400 AM CDT WED AUG 29 2012

...ISAAC BEGINNING TO MOVE INLAND IN SOUTHEAST LOUISIANA...DANGEROUS STORM SURGE AND FLOOD THREAT FROM HEAVY RAINS LIKELY TO CONTINUE THROUGH TODAY AND TONIGHT...



SUMMARY OF 400 AM CDT...0900 UTC...INFORMATION

----------------------------------------------
LOCATION...29.2N 90.5W
ABOUT 30 MI...50 KM SSE OF HOUMA LOUISIANA
ABOUT 60 MI...95 KM SSW OF NEW ORLEANS LOUISIANA
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...969 MB...28.61 INCHES


WATCHES AND WARNINGS

--------------------
CHANGES WITH THIS ADVISORY...

NONE.


SUMMARY OF WATCHES AND WARNINGS IN EFFECT...


A HURRICANE WARNING IS IN EFFECT FOR...

* EAST OF MORGAN CITY LOUISIANA TO THE MISSISSIPPI-ALABAMA BORDER...
INCLUDING METROPOLITAN NEW ORLEANS...LAKE PONTCHARTRAIN...
AND LAKE MAUREPAS

A HURRICANE WATCH IS IN EFFECT FOR...

* INTRACOASTAL CITY TO MORGAN CITY LOUISIANA

A TROPICAL STORM WARNING IS IN EFFECT FOR...

* THE MISSISSIPPI-ALABAMA BORDER TO DESTIN FLORIDA
* MORGAN CITY TO SABINE PASS TEXAS

A TROPICAL STORM WATCH IS IN EFFECT FOR...

* EAST OF HIGH ISLAND TEXAS TO JUST WEST OF SABINE PASS

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST

OFFICE. 


DISCUSSION AND 48-HOUR OUTLOOK

------------------------------
AT 400 AM CDT...0900 UTC...THE CENTER OF HURRICANE ISAAC WAS LOCATED NEAR LATITUDE 29.2 NORTH...LONGITUDE 90.5 WEST. ISAAC IS MOVING TOWARD THE WEST-NORTHWEST NEAR 8 MPH...13 KM/H.  A GENERAL NORTHWESTWARD MOTION AT A SLOWER FORWARD SPEED IS EXPECTED TODAY AND TONIGHT...FOLLOWED BY A TURN TOWARD THE NORTH-NORTHWEST BY THURSDAY NIGHT OR EARLY FRIDAY.  ON THE FORECAST TRACK...THE CENTER OF ISAAC WILL MOVE OVER LOUISIANA TODAY AND TOMORROW AND OVER SOUTHERN ARKANSAS EARLY FRIDAY.

MAXIMUM SUSTAINED WINDS ARE NEAR 80 MPH...130 KM/H...WITH HIGHER GUSTS.  ISAAC IS A CATEGORY ONE HURRICANE ON THE SAFFIR-SIMPSON HURRICANE WIND SCALE.  WEAKENING IS FORECAST AS ISAAC MOVES OVER LAND DURING THE NEXT 48 HOURS.


HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 60 MILES...95 KM...FROM THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 175 MILES...280 KM.  A SUSTAINED WIND OF 51 MPH WITH A GUST TO 66 MPH WAS REPORTED WITHIN THE PAST HOUR AT LAKEFRONT AIRPORT IN NEW ORLEANS.  A SUSTAINED WIND OF 51 MPH WITH A GUST TO 70 MPH WAS REPORTED WITHIN THE PAST HOUR AT BOOTHVILLE LOUISIANA.


ESTIMATED MINIMUM CENTRAL PRESSURE IS 969 MB...28.61 INCHES.



HAZARDS AFFECTING LAND

----------------------
STORM SURGE...THE COMBINATION OF A STORM SURGE AND THE TIDE WILL CAUSE NORMALLY DRY AREAS NEAR THE COAST TO BE FLOODED BY RISING WATERS. THE WATER COULD REACH THE FOLLOWING DEPTHS ABOVE GROUND IF THE PEAK SURGE OCCURS AT THE TIME OF HIGH TIDE...

* MISSISSIPPI AND SOUTHEASTERN LOUISIANA...6 TO 12 FT

* ALABAMA...3 TO 6 FT
* SOUTH-CENTRAL LOUISIANA...3 TO 6 FT
* FLORIDA PANHANDLE AND APALACHEE BAY...2 TO 4 FT

THE DEEPEST WATER WILL OCCUR ALONG THE IMMEDIATE COAST IN AREAS OF ONSHORE WINDS.  SURGE-RELATED FLOODING DEPENDS ON THE RELATIVE TIMING OF THE SURGE AND THE TIDAL CYCLE...AND CAN VARY GREATLY OVER SHORT DISTANCES.  FOR INFORMATION SPECIFIC TO YOUR AREA...PLEASE SEE PRODUCTS ISSUED BY YOUR LOCAL WEATHER SERVICE OFFICE.  NEAR THE COAST...THE SURGE WILL BE ACCOMPANIED BY LARGE AND DANGEROUS WAVES.


WIND...TROPICAL STORM CONDITIONS WILL CONTINUE ACROSS THE WARNING AREA THIS MORNING...AND HURRICANE CONDITIONS WILL CONTINUE TO SPREAD ONSHORE ACROSS SOUTHEASTERN LOUISIANA.


WINDS AFFECTING THE UPPER FLOORS OF HIGH-RISE BUILDINGS WILL BE SIGNIFICANTLY STRONGER THAN THOSE NEAR GROUND LEVEL. AT ABOUT THE 30TH STORY...WINDS WOULD LIKELY BE ONE SAFFIR-SIMPSON CATEGORY STRONGER THAN AT THE SURFACE.


RAINFALL...ISAAC IS EXPECTED TO PRODUCE TOTAL RAINFALL AMOUNTS OF 7 TO 14 INCHES...WITH POSSIBLE ISOLATED MAXIMUM AMOUNTS OF 20 INCHES...OVER MUCH OF LOUISIANA...SOUTHERN MISSISSIPPI...AND SOUTHWEST ALABAMA THROUGH FRIDAY MORNING.  THESE RAINS COULD

RESULT IN SIGNIFICANT LOWLAND FLOODING.  RAINS ARE EXPECTED TO INCREASE NORTHWARD INTO ARKANSAS ON THURSDAY WITH AMOUNTS OF 3 TO 6 INCHES EXPECTED OVER SOUTHERN ARKANSAS BY FRIDAY MORNING.

TORNADOES...ISOLATED TORNADOES ARE POSSIBLE ALONG THE CENTRAL GULF COAST REGION AND PARTS OF THE LOWER MISSISSIPPI RIVER VALLEY THROUGH WEDNESDAY.


SURF...DANGEROUS SURF AND RIP CURRENT CONDITIONS WILL CONTINUE TO AFFECT THE WEST COAST OF FLORIDA AND THE NORTHERN GULF COAST FOR THE NEXT DAY OR SO.

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