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Hurricane Frances Intermediate Advisory Number 30a

Statement as of 8:00 am AST on September 01, 2004

...Dangerous Hurricane Frances heading toward the Bahamas...
A Hurricane Warning is in effect for the southeastern Bahamas...
which includes Acklins...crooked...Inaguas...Mayaguana and
Ragged Islands...and for the Turks and Caicos Islands.

A Hurricane Watch is in effect for the central Bahamas which
includes Cat...Exumas...long islands...Rum Cay and San Salvador.

A Hurricane Warning means that hurricane conditions are expected
within the warning area within the next 24 hours. Preparations to
protect life and property should be rushed to completion. A
Hurricane Watch means that hurricane conditions are possible
within the watch area...generally within 36 hours.

A Tropical Storm Warning remains in effect the north coast of the
Dominican Republic from Punta Gorda westward to Manzanillo Bay.

At 8 am AST...1200z...the eye of Hurricane Frances was located
by a reconnaissance aircraft near latitude 21.4 north...longitude
69.1 west or about 130 miles... 210 km...east of Grand Turk island
or 780 miles...1260 km...east-southeast of Palm Beach Florida.

Frances is moving toward the west-northwest near 16 mph...26 km/hr.
This general motion is expected to continue with a gradual decrease
in forward speed during the next 24 hours. On this track...the
core of the hurricane will be passing near or over the the Turks
and Caicos Islands...and the southeastern Bahamas during the next
24 hours.

Maximum sustained winds are near 140 mph...220 km/hr...with higher
gusts....a category 4 hurricane on the Saffir-Simpson hurricane
scale. While fluctuations in intensity are expected during the
next 24 hours...Frances could still intensify a little more before
reaching the Hurricane Warning area.

Hurricane force winds extend outward up to 80 miles...130 km...
from the center...and tropical storm force winds extend outward up
to 185 miles...295 km.

The latest minimum central pressure reported by an Air Force Reserve
hurricane hunter aircraft was 937 mb...27.67 inches.

Rainfall amounts of 1 to 3 inches...locally higher...are possible
over the Dominican Republic today.

Large and dangerous waves are possible along the north coast of
Hispaniola...and swells generated by Frances will affect portions of
the southeastern coast of the United States today.

Repeating the 8 am AST position...21.4 N... 69.1 W. Movement
toward...west-northwest near 16 mph. Maximum sustained winds...140
mph. Minimum central pressure...937 mb.

For storm information specific to your area...please monitor
products issued by your local weather office.

The next advisory will be issued by the National Hurricane Center at
11 am AST.

Forecaster Avila

Hurricane Frances Discussion Number 30

Statement as of 5:00 am EDT on September 01, 2004

reports from the latest Air Force Reserve hurricane hunter
monitoring Frances show maximum flight-level winds at 700 mb of 123
kt...down a little from the earlier flight. However...the central
pressure has dropped to 935 mb. Based on this...the initial
intensity will remain 120 kt for this advisory. The WSR-88D at San
Juan shows that Frances has concentric eyewalls...and the aircraft
data shows three concentric wind maxima. Indeed...on the latest
pass through the southeastern quadrant the highest wind was in the
maxima associated with the outer eyewall.
The initial motion is a wobbly 285/15. Frances remains on the south
side of a subtropical ridge which large-scale models forecast to
weaken somewhat over the next 72 hr. This should allow the
hurricane to move west-northwestward in the general direction of
the Florida Peninsula. Dynamical model guidance agrees with this
scenario...except for the GFDL which continues to call for a
unrealistic looking motion toward the northwest. The official
forecast through 72 hr is shifted a little west of the previous
track based mainly on the initial position and motion and is on the
left side of the dynamical guidance. After 72 hr...there is
divergence in the guidance as a shortwave ridge develops north of
Frances over the eastern United States. The official forecast
track for that time is shifted to the southwest of the previous
track...although not as far as the UKMET which marches Frances
westward across central Florida and into the Gulf of Mexico.

The intensity forecast is modified only slightly from the previous
package. Upper-level winds are favorable through at least 36-48
hr...so Frances should remain strong. A slight weakening is
indicated at 72 hr based on land interaction and some possible
westerly shear. The main controlling factor on intensity will be
the structure of Frances and concentric eyewall cycles...both of
which are difficult at best to time. Given the current structure
of the hurricane...changes in intensity will likely be relatively
slow to occur.

Forecaster Beven

forecast positions and Max winds

initial 01/0900z 21.2n 68.5w 120 kt
12hr VT 01/1800z 22.0n 70.6w 125 kt
24hr VT 02/0600z 23.2n 72.9w 125 kt
36hr VT 02/1800z 24.3n 74.8w 130 kt
48hr VT 03/0600z 25.5n 76.6w 130 kt
72hr VT 04/0600z 27.0n 79.5w 125 kt
96hr VT 05/0600z 28.5n 81.5w 85 kt...inland
120hr VT 06/0600z 31.0n 84.0w 35 kt...inland