Extratropical Irene Advisories

[cycloneye]

TROPICAL STORM IRENE FORECAST/ADVISORY NUMBER 14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092005
0300Z MON AUG 08 2005

TROPICAL STORM CENTER LOCATED NEAR 21.5N 47.7W AT 08/0300Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 300 DEGREES AT 10 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB
MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT.
34 KT....... 60NE 60SE 0SW 60NW.
12 FT SEAS.. 75NE 75SE 0SW 75NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 21.5N 47.7W AT 08/0300Z
AT 08/0000Z CENTER WAS LOCATED NEAR 21.3N 47.2W

FORECAST VALID 08/1200Z 22.2N 49.0W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 60NE 60SE 0SW 60NW.

FORECAST VALID 09/0000Z 22.9N 50.7W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 60NE 60SE 0SW 60NW.

FORECAST VALID 09/1200Z 23.6N 52.4W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 60NE 60SE 30SW 60NW.

FORECAST VALID 10/0000Z 24.5N 54.0W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 60NE 60SE 60SW 60NW.

FORECAST VALID 11/0000Z 27.0N 57.0W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT... 60NE 60SE 60SW 60NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 325 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 12/0000Z 30.0N 59.0W
MAX WIND 50 KT...GUSTS 60 KT.

OUTLOOK VALID 13/0000Z 33.0N 59.0W
MAX WIND 50 KT...GUSTS 60 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 21.5N 47.7W

NEXT ADVISORY AT 08/0900Z

FORECASTER PASCH

[cycloneye]

316
WTNT44 KNHC 080243
TCDAT4
TROPICAL STORM IRENE DISCUSSION NUMBER 14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT SUN AUG 07 2005

A FEW PATCHES OF DEEP CONVECTION REDEVELOPED NEAR THE CENTER AND IN
A SMALL BAND TO THE EAST AND SOUTHEAST...BUT OVERALL THE CLOUD
PATTERN IS RATHER PALTRY. EVEN THOUGH IRENE DOES NOT LOOK MUCH
LIKE A TROPICAL STORM ON SATELLITE IMAGES...A QUIKSCAT PASS FROM
AROUND 2115 UTC SHOWED SOME UNCONTAMINATED 35 KT VECTORS IN THE
CIRCULATION. THUS THE CURRENT INTENSITY IS KEPT AT 35 KT. THE
SYSTEM SHOULD CONTINUE TO MOVE THROUGH AN ENVIRONMENT OF
NORTHWESTERLY SHEAR AND DRY AIR FOR THE NEXT DAY OR TWO.
AFTERWARDS...ASSUMING IRENE SURVIVES...IT WILL ENCOUNTER WARMER SEA
SURFACE TEMPERATURES AND...PERHAPS...MORE FAVORABLE UPPER-LEVEL
CONDITIONS. THEREFORE SOME STRENGTHENING IS FORECAST AFTER 36
HOURS. THE OFFICIAL INTENSITY FORECAST IS IN GOOD AGREEMENT WITH
THE LATEST SHIPS OUTPUT.

INITIAL MOTION FOR THIS ADVISORY IS 300/10. THERE IS LITTLE CHANGE
TO THE SYNOPTIC REASONING FOR THE TRACK FORECAST. IRENE IS BEING
STEERED BY THE FLOW TO THE SOUTHWEST OF A MID-LEVEL ANTICYCLONE. A
GRADUAL TURN TO THE RIGHT...INTO A WEAKNESS IN THE SUBTROPICAL
RIDGE...IS EXPECTED TO BEGIN IN A COUPLE OF DAYS. THE OFFICIAL
FORECAST IS SIMILAR TO THE PREVIOUS ONE.

FORECASTER PASCH


FORECAST POSITIONS AND MAX WINDS

INITIAL 08/0300Z 21.5N 47.7W 35 KT
12HR VT 08/1200Z 22.2N 49.0W 35 KT
24HR VT 09/0000Z 22.9N 50.7W 35 KT
36HR VT 09/1200Z 23.6N 52.4W 35 KT
48HR VT 10/0000Z 24.5N 54.0W 40 KT
72HR VT 11/0000Z 27.0N 57.0W 45 KT
96HR VT 12/0000Z 30.0N 59.0W 50 KT
120HR VT 13/0000Z 33.0N 59.0W 50 KT

[Brent]

BULLETIN
TROPICAL STORM IRENE ADVISORY NUMBER 14
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM AST SUN AUG 07 2005

...POORLY-ORGANIZED IRENE CONTINUES WEST-NORTHWESTWARD OVER THE
CENTRAL ATLANTIC...

AT 11 PM AST...0300Z...THE CENTER OF TROPICAL STORM IRENE WAS
LOCATED NEAR LATITUDE 21.5 NORTH... LONGITUDE 47.7 WEST OR ABOUT
1025 MILES...1650 KM... EAST-NORTHEAST OF THE NORTHERN LEEWARD
ISLANDS.

IRENE IS MOVING TOWARD THE WEST-NORTHWEST NEAR 12 MPH
...19 KM/HR...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR
THE NEXT 24 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 40 MPH... 65 KM/HR...WITH HIGHER
GUSTS. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 24
HOURS.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 70 MILES
...110 KM FROM THE CENTER.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB...29.68 INCHES.

REPEATING THE 11 PM AST POSITION...21.5 N... 47.7 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 12 MPH. MAXIMUM SUSTAINED
WINDS... 40 MPH. MINIMUM CENTRAL PRESSURE...1005 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
5 AM AST.

FORECASTER PASCH

[arlwx]

Tropical Storm Irene Advisory Number 15


Statement as of 5:00 am AST on August 08, 2005


...Irene moving west-northwestward through the open Atlantic as a
minimal tropical storm...

at 5 am AST...0900z...the center of tropical storm Irene was located
near latitude 21.9 north...longitude 48.9 west or about 955
miles...1540 km...east-northeast of the northern Leeward Islands.

Irene is moving toward the west-northwest near 14 mph...22 km/hr...
and this general motion is expected to continue for the next 24
hours.

Maximum sustained winds are near 40 mph... 65 km/hr...with higher
gusts. Little change in strength is forecast during the next 24
hours.

Tropical storm force winds extend outward up to 70 miles
...110 km from the center.

Estimated minimum central pressure is 1006 mb...29.71 inches.

Repeating the 5 am AST position...21.9 N... 48.9 W. Movement
toward...west-northwest near 14 mph. Maximum sustained
winds... 40 mph. Minimum central pressure...1006 mb.

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

Forecaster Beven

[arlwx]

Tropical Storm Irene Discussion Number 15


Statement as of 5:00 am EDT on August 08, 2005


A new burst of convection has developed just east of the center of
Irene during the past 6 hr...although the burst is less impressive
that the one at this time last night. Satellite intensity estimates
are 30 kt from all agencies...and based on this Irene may have
weakened to a depression. However...any downgrade can wait until
after data from the next Quikscat overpass arrives. The initial
intensity remains 35 kt for this package.
The 12-hr initial motion is 295/12...and the short-term motion may
be a little left of that and faster. Irene remains south of a
low/mid-level ridge...with large-models forecasting this to persist
for 48-72 hr. This should keep Irene on a general west-northwest
heading for that time. Beyond 72 hr...many models forecast Irene
to turn more northward into a weakness in the ridge caused by a
frontal system moving off the U. S. Northeast coast. The dynamical
models agree on this scenario...with the UKMET and NOGAPS turning
Irene northeastward after 96 hr...the NOGAPS doing so in spite of a
significant westward shift since its last run. On the other
hand...the BAM models do not show a northward turn...continuing
Irene west-northwestward through 120 hr. The official forecast
track continues to show a northerly turn after 72 hr...although the
entire track has been shifted somewhat westward from 6 hr ago.
However...the track is not as far west as the NOGAPS and UKMET are
through 96 hr...and it may have to be shifted farther westward
after the next round of model runs.
Irene is in an environment of moderate northwesterly vertical
shear...and this will likely continue for 36-48 hr. This should
limit strengthening even though the storm will be moving over
warmer sea surface temperatures. After that time...the large-scale
models are in poor agreement on the evolution of the upper-level
winds near Irene. The NOGAPS builds a large anticyclone over the
storm...while the GFS...UKMET...and Canadian build a more modest
ridge. How much of this development is due to the model outflow
from Irene is unknown...but it is possible that the models may be
overdoing this more favorable environment. The intensity forecast
is based on a gradual decrease in shear that will allow some
strengthening through 72 hr. After that...the forecast track takes
Irene over cooler SSTs...which should limit strengthening. The
intensity forecast is based on the SHIPS model. It should be noted
that the GFDL is again dissipating Irene in less than 48 hr.

Forecaster Beven


forecast positions and Max winds

initial 08/0900z 21.9n 48.9w 35 kt
12hr VT 08/1800z 22.6n 50.5w 35 kt
24hr VT 09/0600z 23.4n 52.4w 35 kt
36hr VT 09/1800z 24.2n 54.1w 40 kt
48hr VT 10/0600z 25.1n 55.9w 45 kt
72hr VT 11/0600z 27.0n 58.5w 50 kt
96hr VT 12/0600z 30.0n 60.5w 50 kt
120hr VT 13/0600z 33.0n 60.0w 50 kt

[HURAKAN]

Irene weakens to a depression, not a surprise at all!

[cycloneye]

KNHC 081438
TCMAT4
TROPICAL DEPRESSION IRENE FORECAST/ADVISORY NUMBER 16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092005
1500Z MON AUG 08 2005

TROPICAL DEPRESSION CENTER LOCATED NEAR 22.4N 50.7W AT 08/1500Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 14 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1009 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 22.4N 50.7W AT 08/1500Z
AT 08/1200Z CENTER WAS LOCATED NEAR 22.2N 49.9W

FORECAST VALID 09/0000Z 22.9N 52.1W
MAX WIND 30 KT...GUSTS 40 KT.

FORECAST VALID 09/1200Z 23.5N 54.3W
MAX WIND 30 KT...GUSTS 40 KT.

FORECAST VALID 10/0000Z 24.0N 56.5W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 60NE 60SE 60SW 60NW.

FORECAST VALID 10/1200Z 24.6N 58.8W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 60NE 60SE 60SW 60NW.

FORECAST VALID 11/1200Z 26.5N 63.0W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 60NE 60SE 60SW 60NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 325 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 12/1200Z 29.0N 66.5W
MAX WIND 45 KT...GUSTS 55 KT.

OUTLOOK VALID 13/1200Z 31.0N 67.0W
MAX WIND 45 KT...GUSTS 55 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 22.4N 50.7W

NEXT ADVISORY AT 08/2100Z

[cycloneye]

TROPICAL DEPRESSION IRENE ADVISORY NUMBER 16
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM AST MON AUG 08 2005

...IRENE WEAKENS TO A TROPICAL DEPRESSION...

AT 11 AM AST...1500Z...THE CENTER OF TROPICAL DEPRESSION IRENE WAS
LOCATED NEAR LATITUDE 22.4 NORTH... LONGITUDE 50.7 WEST OR ABOUT
855 MILES...1375 KM... EAST-NORTHEAST OF THE NORTHERN LEEWARD
ISLANDS.

THE DEPRESSION IS MOVING TOWARD THE WEST-NORTHWEST NEAR 16 MPH
...26 KM/HR...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE DURING
THE NEXT 24 HOURS.

MAXIMUM SUSTAINED WINDS ARE NEAR 35 MPH... 55 KM/HR...WITH HIGHER
GUSTS. LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 24
HOURS.

ESTIMATED MINIMUM CENTRAL PRESSURE IS 1009 MB...29.80 INCHES.

REPEATING THE 11 AM AST POSITION...22.4 N... 50.7 W. MOVEMENT
TOWARD...WEST-NORTHWEST NEAR 16 MPH. MAXIMUM SUSTAINED
WINDS... 35 MPH. MINIMUM CENTRAL PRESSURE...1009 MB.

THE NEXT ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT
5 PM AST.

[Thunder44]

The track has been shifted much further left than the previous advisory.

[cycloneye]

The track has been shifted much further left than the previous advisory.

Yes now it passes the Bermuda Longitud.

[wxwatcher91]

Tropical Depression Irene Discussion Number 16


Statement as of 11:00 am EDT on August 08, 2005



the exposed low-level circulation has become increasingly separated
from what is left of the convection to its east that occurred
overnight. A Quikscat overpass near 0820z missed most of the
circulation but did indicate some 35 kt winds just outside of the
deep convection in the northeastern quadrant. However... at that
time the convection was deeper and more involved with the low-level
center than it has been during the past couple of hours... so it is
probably safe to assume that the winds have decreased since then.
Dvorak intensity estimates have also fallen to 30 kt. Irene is
therefore downgraded to a tropical depression with 30 kt winds. A
limited amount of convection has resumed just east of the
center...but it remains to be seen if this is the start of a
comeback. The intensity forecast is adjusted downward from the
previous advisory...and closer to the GFDL than the SHIPS guidance.

The track and intensity forecasts are always interdependent to some
degree...but for Irene...especially in the 3-5 day period...one
could affect the other perhaps more so than usual. The initial
motion estimate is 285/14. Based on a Irene remaining weaker than
previously expected...a continued west-northwestward motion within
the low to mid level flow is forecast until very late in the
forecast...which would take the system farther west than the
previous advisory. This scenario is in best agreement with the
GFDL...ECMWF...and BAM shallow solutions.

Forecaster Knabb


forecast positions and Max winds

initial 08/1500z 22.4n 50.7w 30 kt
12hr VT 09/0000z 22.9n 52.1w 30 kt
24hr VT 09/1200z 23.5n 54.3w 30 kt
36hr VT 10/0000z 24.0n 56.5w 35 kt
48hr VT 10/1200z 24.6n 58.8w 40 kt
72hr VT 11/1200z 26.5n 63.0w 40 kt
96hr VT 12/1200z 29.0n 66.5w 45 kt
120hr VT 13/1200z 31.0n 67.0w 45 kt


$$

[wxman57]

Interesting that I'm measuring a steady 296.7 deg movement at 16 kts and the NHC moves it at 8 kts for the first 9 hours then 9.5 kts for the next 72-84 hours and down to 6 kts the last 24 hours.

The center should be well past their 00Z position by 21Z. As for the new track, it's a hedge. Either Irene gets ripped apart by shear or some low-level energy could continue WNW, but possibly south of the new NHC track.

[Ivanhater]

Interesting that I'm measuring a steady 296.7 deg movement at 16 kts and the NHC moves it at 8 kts for the first 9 hours then 9.5 kts for the next 72-84 hours and down to 6 kts the last 24 hours.

The center should be well past their 00Z position by 21Z. As for the new track, it's a hedge. Either Irene gets ripped apart by shear or some low-level energy could continue WNW, but possibly south of the new NHC track.

thats what im saying in the irene thread, i was under the assumption it either caught the weakness or missed it all together, maybe you can help

[cycloneye]

082040
TCMAT4
TROPICAL DEPRESSION IRENE FORECAST/ADVISORY NUMBER 17
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL092005
2100Z MON AUG 08 2005

TROPICAL DEPRESSION CENTER LOCATED NEAR 22.5N 51.5W AT 08/2100Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 10 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1009 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 22.5N 51.5W AT 08/2100Z
AT 08/1800Z CENTER WAS LOCATED NEAR 22.4N 50.9W

FORECAST VALID 09/0600Z 23.0N 53.1W
MAX WIND 30 KT...GUSTS 40 KT.

FORECAST VALID 09/1800Z 23.6N 55.4W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 60NE 40SE 20SW 60NW.

FORECAST VALID 10/0600Z 24.3N 57.8W
MAX WIND 35 KT...GUSTS 45 KT.
34 KT... 60NE 40SE 20SW 60NW.

FORECAST VALID 10/1800Z 25.1N 59.7W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 60NE 40SE 20SW 60NW.

FORECAST VALID 11/1800Z 27.0N 63.5W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT... 60NE 40SE 20SW 60NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
ON DAY 4 AND 325 NM ON DAY 5...AND FOR INTENSITY NEAR 20 KT EACH DAY

OUTLOOK VALID 12/1800Z 29.5N 66.5W
MAX WIND 45 KT...GUSTS 55 KT.

OUTLOOK VALID 13/1800Z 31.5N 67.0W
MAX WIND 45 KT...GUSTS 55 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 22.5N 51.5W

NEXT ADVISORY AT 09/0300Z

FORECASTER KNABB

[cycloneye]

[deltadog03]

ok, that is .1N and .8W in 6 hours folks...almost due WEST...irene is going to give someone fits...

[Ivanhater]

westward ho!!

[feederband]

Hmmmm .....just hmmmm...

[Ivanhater]

Tropical Depression Irene Discussion Number 17


Statement as of 5:00 PM EDT on August 08, 2005



convection has persisted to the east of the low level
center this afternoon... often emanating from the center itself.
However... the low level center remains exposed Dvorak intensity
estimates remain t2.0/30 kt. Although it is possible that tropical
storm force winds are reaching the surface in a limited area within
the sparse convection... Irene is maintained as 30 kt depression
for this advisory. The system is struggling to reorganize within a
fairly dry and stable environment with moderate vertical shear.
These conditions should be slow to change along the forecast
track... and accordingly the SHIPS guidance shows gradual
strengthening to 45 kt by 60 hours...continuing on to 62 kt by 120
hours. However... the GFDL dissipates the system within a couple
of days. The official forecast will compromise and remain similar
to the previous advisory... showing modest and gradual
strengthening.

When the convection redeveloped this morning... the low level center
slowed down in response. Smoothing through the stop-and-go motion
during the past 12 hours or so yields an initial motion of 285/10.
The new official forecast is basically an update of the previous
advisory... and there is a little more confidence in this track now
since some of the models that were eastern outliers this morning...
such as the UKMET and NOGAPS... have shifted westward.
Therefore... models are coming into better agreement that a system
of moderate tropical storm strength will move west-northwestward
along the southern periphery of the lower/mid level subtropical
ridge. The slow motion shown at the end of the official forecast
is indicative of the great uncertainty late in the period...when
the spread in the models is still quite significant.

Forecaster Knabb


forecast positions and Max winds

initial 08/2100z 22.5n 51.5w 30 kt
12hr VT 09/0600z 23.0n 53.1w 30 kt
24hr VT 09/1800z 23.6n 55.4w 35 kt
36hr VT 10/0600z 24.3n 57.8w 35 kt
48hr VT 10/1800z 25.1n 59.7w 40 kt
72hr VT 11/1800z 27.0n 63.5w 40 kt
96hr VT 12/1800z 29.5n 66.5w 45 kt
120hr VT 13/1800z 31.5n 67.0w 45 kt

[cycloneye]

342
WTNT44 KNHC 082102
TCDAT4
TROPICAL DEPRESSION IRENE DISCUSSION NUMBER 17
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT MON AUG 08 2005

CONVECTION HAS PERSISTED TO THE EAST OF THE LOW LEVEL
CENTER THIS AFTERNOON... OFTEN EMANATING FROM THE CENTER ITSELF.
HOWEVER... THE LOW LEVEL CENTER REMAINS EXPOSED DVORAK INTENSITY
ESTIMATES REMAIN T2.0/30 KT. ALTHOUGH IT IS POSSIBLE THAT TROPICAL
STORM FORCE WINDS ARE REACHING THE SURFACE IN A LIMITED AREA WITHIN
THE SPARSE CONVECTION... IRENE IS MAINTAINED AS 30 KT DEPRESSION
FOR THIS ADVISORY. THE SYSTEM IS STRUGGLING TO REORGANIZE WITHIN A
FAIRLY DRY AND STABLE ENVIRONMENT WITH MODERATE VERTICAL SHEAR.
THESE CONDITIONS SHOULD BE SLOW TO CHANGE ALONG THE FORECAST
TRACK... AND ACCORDINGLY THE SHIPS GUIDANCE SHOWS GRADUAL
STRENGTHENING TO 45 KT BY 60 HOURS...CONTINUING ON TO 62 KT BY 120
HOURS. HOWEVER... THE GFDL DISSIPATES THE SYSTEM WITHIN A COUPLE
OF DAYS. THE OFFICIAL FORECAST WILL COMPROMISE AND REMAIN SIMILAR
TO THE PREVIOUS ADVISORY... SHOWING MODEST AND GRADUAL
STRENGTHENING.

WHEN THE CONVECTION REDEVELOPED THIS MORNING... THE LOW LEVEL CENTER
SLOWED DOWN IN RESPONSE. SMOOTHING THROUGH THE STOP-AND-GO MOTION
DURING THE PAST 12 HOURS OR SO YIELDS AN INITIAL MOTION OF 285/10.
THE NEW OFFICIAL FORECAST IS BASICALLY AN UPDATE OF THE PREVIOUS
ADVISORY... AND THERE IS A LITTLE MORE CONFIDENCE IN THIS TRACK NOW
SINCE SOME OF THE MODELS THAT WERE EASTERN OUTLIERS THIS MORNING...
SUCH AS THE UKMET AND NOGAPS... HAVE SHIFTED WESTWARD.
THEREFORE... MODELS ARE COMING INTO BETTER AGREEMENT THAT A SYSTEM
OF MODERATE TROPICAL STORM STRENGTH WILL MOVE WEST-NORTHWESTWARD
ALONG THE SOUTHERN PERIPHERY OF THE LOWER/MID LEVEL SUBTROPICAL
RIDGE. THE SLOW MOTION SHOWN AT THE END OF THE OFFICIAL FORECAST
IS INDICATIVE OF THE GREAT UNCERTAINTY LATE IN THE PERIOD...WHEN
THE SPREAD IN THE MODELS IS STILL QUITE SIGNIFICANT.

FORECASTER KNABB


FORECAST POSITIONS AND MAX WINDS

INITIAL 08/2100Z 22.5N 51.5W 30 KT
12HR VT 09/0600Z 23.0N 53.1W 30 KT
24HR VT 09/1800Z 23.6N 55.4W 35 KT
36HR VT 10/0600Z 24.3N 57.8W 35 KT
48HR VT 10/1800Z 25.1N 59.7W 40 KT
72HR VT 11/1800Z 27.0N 63.5W 40 KT
96HR VT 12/1800Z 29.5N 66.5W 45 KT
120HR VT 13/1800Z 31.5N 67.0W 45 KT