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Tropical Storm Arlene Discussion Number 12
Statement as of 4:00 am CDT on June 11, 2005

 
infrared satellite imagery indicates that convection associated with
Arlene has become rather disorganized...with no new significant
convective bursts to replace the one that dissipated just after
00z.  An Air Force Reserve hurricane hunter has found maximum
flight-level winds of 69 kt well northeast of the center at 850
mb...along with a minimum central pressure of 993 mb.  Comparison
of aircraft winds with buoys and C-man stations south of
Apalachicola suggests the flight-level winds are not being mixed to
the surface at the normal 70-80 percent values...at least at that
distance from the center.  The maximum sustained winds will remain
60 kt for this advisory...although this might be a bit generous.

 
The initial motion is 320/16.  Arlene is being steered by deep layer
ridging over the eastern United States...with all available
guidance indicating the storm should gradually recurve around the
western periphery of the ridge over the next two days.  All
dynamical models agree with this scenario...and the official
forecast calls for arelene to gradually turn north-northwestward
before landfall on the northern Gulf Coast in 12-18 hr.  Gradual
recurvature into the westerlies is expected after landfall.

 
There seem to be two possibilities for the intensity before
landfall.  The first is that a new convective burst develops during
the upcoming diurnal maximum...and Arlene makes another attempt to
become a hurricane.  The intensity forecast will follow this
possibility.  However...the second possibility is that the abundant
dry air seen in water vapor imagery near Arlene has been entrained
into the storm and will suppress convection during the remaining
time before landfall.  If that happens...Arlene may well weaken
before landfall.  It will likely take one more forecast cycle
before it becomes clear which possibility is occurring.

 
There is a distinct possibility that Arlene will not become a
hurricane.  However...the Hurricane Warning for the northern Gulf
Coast will remain in effect until it becomes clear that this will
not happen.

 
Forecaster Beven

Tropical Storm Arlene Intermediate Advisory Number 12a

Statement as of 7:00 am CDT on June 11, 2005

...Arlene continues toward the northern Gulf Coast as a strong
tropical storm...

a Hurricane Warning remains in effect for portions of the north
central Gulf Coast from Pascagoula Mississippi eastward to Destin
Florida. A Hurricane Warning means that hurricane conditions are
expected within the warning area...generally within 24 hours.

A Hurricane Watch and a Tropical Storm Warning remain in effect
from the mouth of the Pearl River eastward to west of Pascagoula
Mississippi...and also from east of Destin Florida eastward to
Indian Pass Florida. A Hurricane Watch means that hurricane
conditions are possible within the watch area...generally within
36 hours.

A Tropical Storm Warning remains in effect for the northern Gulf
Coast from Grand Isle Louisiana to the mouth of the Pearl
River.....Including the city of New Orleans and Lake
Pontchartrain...and also from Indian Pass Florida eastward to
Steinhatchee river Florida. A Tropical Storm Warning means that
tropical storm conditions are expected within the warning area
within the next 24 hours.

Interests elsewhere in the eastern Gulf of Mexico and adjacent land
areas should closely monitor the progress of this system.

For storm information specific to your area...including possible
inland watches and warnings...please monitor products issued
by your local weather office.

At 7 am CDT...1200z...the center of Tropical Storm Arlene was
located by a reconnaissance plane near latitude 29.0 north...
longitude 87.2 west or about 115 miles east of the mouth of the
Mississippi River and about 105 miles south-southeast of Mobile
Alabama.

Arlene is moving toward the north-northwest near 15 mph. This
motion should bring the center of Arlene to the northern Gulf Coast
later today.

Maximum sustained winds remain near 70 mph...with higher gusts.
There is still potential for Arlene to become a hurricane before
landfall.

Tropical storm force winds extend outward up to 160 miles...mainly
to the north and east of the center.

The minimum central pressure just reported by an Air Force Reserve
hurricane hunter aircraft is 990 mb...29.23 inches.

Coastal storm surge flooding of 3 to 5 feet above normal tide
levels...along with large and dangerous battering waves...can be
expected near and to the east of where the center makes landfall.
Water levels are currently about one foot above normal tide
levels along the northern Gulf Coast.

Arlene is expected to produce total rain accumulations of 4 to 8
inches along and to the east of the forecast track across the
Florida Panhandle...the southeast...the Tennessee Valley...and into
the lower to middle Ohio Valley. Isolated maximum amounts of up to
10 inches are possible along the eastern Gulf Coast.

Isolated tornadoes are possible over portions of southern
Alabama...southwestern Georgia...the Florida Panhandle...and
northwestern Florida today.

Repeating the 7 am CDT position...29.0 N... 87.2 W. Movement
toward...north northwest near 15 mph. Maximum sustained
winds... 70 mph. Minimum central pressure...990 mb.

The next advisory will be issued by the National Hurricane Center at
10 am CDT.

Forecaster Avila/Knabb