Katrina Becomes the 3rd MAJOR Hurricane!

[JamesFromMaine2]

Hurricane Katrina Advisory Number 16

Statement as of 5:00 am EDT on August 27, 2005


...Katrina becomes a major hurricane with 115 mph winds...

At 5 am EDT... 0900z... the Tropical Storm Warning has been
discontinued from the Seven Mile Bridge to Key Largo Florida and
for Florida Bay. A Tropical Storm Warning remains in effect from
west of the Seven Mile Bridge westward to Key West including the
Dry Tortugas.


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


At 5 am EDT...0900z...the eye of Hurricane Katrina was located by
radar and reconnaissance aircraft near latitude 24.4 north...
longitude 84.4 west or about 435 miles southeast of the mouth of
the Mississippi River and about 165 miles west of Key West Florida.


Katrina is moving toward the west near 7 mph... 11 km/hr. A
gradual turn toward the west-northwest is expected during the next
24 hours.


Maximum sustained winds are near 115 mph...with higher gusts.
Katrina is a category three hurricane on the Saffir-Simpson scale.
Some strengthening is forecast during the next 24 hours.


Reconnaissance aircraft data and surface observations indicate that
Katrina has become a larger hurricane. Hurricane force winds extend
outward up to 40 miles from the center...and tropical storm force
winds extend outward up to 150 miles. Tropical storm force winds
are occurring just offshore of the northern coast of western Cuba.


The minimum central pressure recently reported by an Air Force
reconnaissance aircraft was 945 mb...27.91 inches.

Storm surge flooding of 2 to 4 feet above normal tide levels...
can be expected along the southwest coast of Florida in areas of
onshore flow east of Cape Sable... and in Florida Bay. Storm surge
will gradually subside today.


Katrina is expected to produce rainfall amounts of 5 to 10 inches
over western Cuba... and 1 to 3 inches of rainfall is expected
over the Yucatan Peninsula. Rainfall is expected to slowly diminish
across the lower Florida Keys today... although an additional 1 to 2
inches of rain is possible in some of the heavier rain bands.


Isolated tornadoes are possible this morning over the lower Florida
Keys.


Repeating the 5 am EDT position...24.4 N... 84.4 W. Movement
toward...west near 7 mph. Maximum sustained
winds...115 mph. Minimum central pressure... 945 mb.


An intermediate advisory will be issued by the National Hurricane
Center at 8 am EDT followed by the next complete advisory at 11 am
EDT.


Forecaster Knabb

[ConvergenceZone]

yep, pretty much did what we thought it would by the 5:00 am update. The eye is really starting to show up now on the latest satellite photos

[Matt-hurricanewatcher]

The recon found very little support for the increase. But I guest 112 mph surface=a cat3. You have to remember that Emily was over 156 mph by the recon data. But she was never upgraded but it was runed down to 155 mph. But I guest this is the way it works.

[ConvergenceZone]

don't know. The sharp pressure falls and improved satellite signature is enough to raise it in my opinion.

[FritzPaul]

From 5am Disc:

THE EYE HAS BECOME CLEARLY DISCERNIBLE DURING THE PAST FEW HOURS IN
GOES-12 INFRARED IMAGERY. AIRCRAFT RECONNAISSANCE INDICATES THE
MINIMUM CENTRAL PRESSURE IS FALLING... MOST RECENTLY MEASURED AT
945 MB. WHILE SUCH A LOW PRESSURE IS TYPICAL OF SOME CATEGORY FOUR
HURRICANES... THE MAXIMUM 700 MB FLIGHT LEVEL WINDS HAVE NOT YET
EXCEEDED 104 KT WHICH CORRESPONDS TO ABOUT 95 KT AT THE SURFACE. GIVEN THE FALLING PRESSURE... AND DVORAK INTENSITY ESTIMATES
RANGING FROM 100 TO 115 KT... THE ADVISORY INTENSITY WILL BE
INCREASED TO 100 KT... MAKING KATRINA A CATEGORY THREE HURRICANE.
THE AIRCRAFT DATA AND A FEW SURFACE OBSERVATIONS ALSO INDICATE THAT
KATRINA HAS GROWN IN SIZE... WHICH PERHAPS EXPLAINS WHY THE MAXIMUM
WINDS HAVE NOT YET CAUGHT UP TO THE CENTRAL PRESSURE. THE INITIAL
AND FORECAST WIND RADII HAVE BEEN EXPANDED ACCORDINGLY.

[Mac]

Which was my exact point in another thread.

There is more error involved in making intensity estimates by sat presentation than by pressure readings. The pressures don't lie.

Her winds just haven't caught up to the pressure yet because she has expanded her wind field. When she does, she'll quickly go to cat 4, IMO.

[senorpepr]

Which was my exact point in another thread.

There is more error involved in making intensity estimates by sat presentation than by pressure readings. The pressures don't lie.

Her winds just haven't caught up to the pressure yet because she has expanded her wind field. When she does, she'll quickly go to cat 4, IMO.

Pressures don't always match up to wind speed. A) pressures drop before winds increase and B) the pressures only depend on the background pressure. A lower background pressure will falsely dip the pressure lower than normal.