ATL: TROPICAL DEPRESSION HENRI (10L)

[Gustywind]

000
AXNT20 KNHC 061046
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT TUE OCT 06 2009

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST
FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED
ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1000 UTC.

...SPECIAL FEATURES...

AN ACTIVE TROPICAL WAVE EXTENDS FROM 20N47W TO 10N54W MOVING WNW
NEAR 13 KT. SATELLITE IMAGERY INDICATES A 1010 MB SURFACE LOW
CIRCULATION ALONG THE WAVE AXIS NEAR 16N50W. THE WAVE COINCIDES
WITH A DEEP LAYER MOISTURE MAXIMUM OBSERVED IN TOTAL
PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/STRONG CONVECTION
IS FROM 13N-18N BETWEEN 48W-51W. ISOLATED MODERATE CONVECTION IS
TO THE NE DUE TO UPPER LEVEL SHEAR FROM 19N-21N BETWEEN 43W-51W.
THERE IS A MEDIUM CHANCE...30 TO 50 PERCENT...OF THIS SYSTEM
BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HRS.

$$
WALTON

[caribepr]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
311 AM AST TUE OCT 6 2009

.SYNOPSIS...TROPICAL WAVE EXITED THE REGION OVERNIGHT AND HAS
TRACKED A MUCH DRIER AIR MASS INTO THE REGION. EXPECT A DRYING
TREND THROUGH THE WEEK AS A MUCH MORE STABLE AIRMASS MOVES INTO
THE REGION. A STRONG TROPICAL WAVE MAY AFFECT THE REGION THIS
UPCOMING WEEKEND...INCREASING SHOWER AND THUNDERSTORM ACTIVITY
ACROSS THE ENTIRE AREA.


&&

.DISCUSSION...THREE TROPICAL WAVES OF INTEREST ARE THE MAIN PLAYERS IN
TERMS OF LOW LEVEL MOISTURE ADVECTION OVER THE NEXT 5-7 DAYS. THE
FIRST...EXITING THE REGION OVERNIGHT IS HEADED FOR HISPANIOLA AND
TRAILING A MUCH DRIER AIR MASS INTO THE VI/PR NOTABLE ON RADAR AND
SATELLITE. A SECOND...VERY WEAK AND LOW AMPLITUDE WAVE ALONG 60W
OVER THE LEEWARD ISLANDS WILL TRACK WESTWARD THROUGH THE SE
CARIBBEAN THROUGH 36 HOURS. THIS WILL LIKELY EVEN DRY OUT THE
ATMOSPHERE MORE...AS DRY AIR ALONG THE TOP EDGE OF THE WAVE
ADVECTS INTO LOCAL AREA NEXT 36 HOURS. THE THIRD FEATURE...THE
STRONGEST WAVE OF THE THREE IS NEAR 50 WEST AND IS FORECAST TO
HEAD SLOWLY NORTHWESTWARD OVER THE NEXT FEW DAYS...RUNNING INTO A
SOLID WALL OF SOUTHWESTERLY SHEAR. DRY AIR SURROUNDS ALL THREE
SYSTEMS AND WILL BE OVER PUERTO RICO FOR MOST OF THE
WEEK...ESPECIALLY THURSDAY AND FRIDAY AS MID LEVEL RIDGING BECOMES
STRONG OVER THE SW ATLC.

THEREFORE...EXPECTING ONLY ONE MORE DAY OF MODERATE CONVECTION OVER
WESTERN PUERTO RICO THIS AFTERNOON...FOLLOWED BY A SHARP DRYING
TREND WITH STRONG CAPPING TO BUILD AT TOP OF BOUNDARY
LAYER...ENSURING ONLY ISOLATED ACTIVITY AND PLENTY OF SUN FOR THE
REST OF THE WEEK.

BY THE WEEKEND...THE THIRD WAVE MENTIONED ABOVE IS FORECAST TO
WOBBLE AND DIVE SOUTHWESTWARD AND TRACK DEEP MOISTURE ADVECTION INTO
LOCAL REGION. LOOKS LIKE A WET WEEKEND AHEAD...BUT WILL HIGHLY
DEPEND ON THE LONGEVITY OF THIS WAVE.

http://forecast.weather.gov/product.php ... glossary=1

Lots of words to say we may have a lot of rain...or we may not! Good head's up though to remind the complacent that the season is NOT over.

[Blown Away]

NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0037 UTC TUE OCT 6 2009

DISTURBANCE INVEST (AL912009) 20091006 0000 UTC
LAT LON LAT LON LAT LON LAT LON
...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
091008 0000 091009 0000 091010 0000 091011 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 22.0N 58.6W 24.6N 60.5W 24.9N 56.6W 22.6N 53.3W
BAMD 21.6N 54.1W 22.8N 54.7W 19.4N 55.6W 16.8N 60.7W
BAMM 21.0N 55.6W 22.9N 58.0W 21.7N 59.5W 20.5N 63.0W
LBAR 22.9N 51.1W 24.8N 47.0W 26.8N 41.3W 29.6N 33.0W
SHIP 44KTS 36KTS 33KTS 38KTS
DSHP 44KTS 36KTS 33KTS 38KTS

May not mean anything but Ships showing a slight increase in intensity at 120 hours?

[cycloneye]

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
800 AM EDT TUE OCT 6 2009

FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...

SHOWERS AND THUNDERSTORMS ASSOCIATED WITH AN AREA OF LOW PRESSURE
LOCATED ABOUT 575 MILES EAST OF THE LEEWARD ISLANDS HAVE BECOME
LESS ORGANIZED OVER THE PAST FEW HOURS. UPPER-LEVEL WINDS NO
LONGER APPEAR CONDUCIVE FOR DEVELOPMENT OF THIS SYSTEM AS IT MOVES
NORTHWESTWARD NEAR 15 MPH. THERE IS A LOW CHANCE...LESS THAN 30
PERCENT...OF THIS SYSTEM BECOMING A TROPICAL CYCLONE DURING THE
NEXT 48 HOURS.

ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.

$$
FORECASTER BERG

[Blown Away]

TPC's 72 hour forecast.

[HURAKAN]

Latest

[Gustywind]

From Crownweather Discussion:
Discussion http://www.crownweather.com/?page_id=325
I continue to keep an eye on a broad area of low pressure, Invest 91L, located about 750 miles east of the Lesser Antilles. This system is tracking west-northwest at a forward speed of 15 mph. This forward movement is expected to continue for the next 2 to 3 days or so. Satellite imagery this morning indicated that this system is still quite disorganized, however, shear tendencies indicate that overall shear is decreasing over Invest 91L. The shear forecast calls for an increase in shear over the next 24 to 36 hours and this will likely further disrupt the organization of Invest 91L; however, shear values are forecast to decrease to around 10 knots or less by Thursday and Invest 91L may start organizing and developing by late this week.

As I have already mentioned, Invest 91L is expected to track west-northwest over the next 2 to 3 days and may turn back to the west by late this week. Interests in the northern Leeward Islands, the Virgin Islands and Puerto Rico should keep an eye on Invest 91L. At this point, I think very slow development is likely from Invest 91L. For the next couple of days or so, I expect Invest 91L to become less organized due to higher wind shear values, however, it may become more organized by late this week and it is possible that Invest 91L may be a tropical depression by this weekend as it gets close to the Virgin Islands and Puerto Rico.

It should be noted that the only global model that forecasts development is the Canadian model and that model even forecasts weak development; so, it is highly possible that Invest 91L will not survive the shear over the next couple of days.

[HURAKAN]

Great structure

[wxman57]

Current surface analysis/satellite indicates that the rotation we're seeing may not be at the surface. Note the buoy with the persistent easterly wind south of the rotation. Center is near 16.8N/52.1W. Maybe a little east of that point though, based on a newer image. Experiencing moderate shear. Models are often clueless about shear over the open waters. We just don't have adequate data out there. Development chances definitely diminishing, as per the now "code yellow". Good news for you folks in the Caribbean.

[Blown Away]

Recent convection building on the SE quadrant.
http://www.ssd.noaa.gov/goes/east/tatl/loop-vis.html

[gatorcane]

looks like it is starting to show hints of a more WNW bend already. Also convection is increasing again. There is a swath of some good SW shear that it is heading through now (which was forecasted by GFS), but after that, north of the Caribbean, doesn't look all that bad (10-15K of shear at the moment) so we'll see how it handles this shear. I wouldn't write it off quite yet.

[HURAKAN]

Semi-exposed now

[Blown Away]

Convection continues to build over the LLC.

[HURAKAN]

12 UTC Best Track

AL, 91, 2009100612, , BEST, 0, 169N, 518W, 30, 1007

[HURAKAN]

766
WHXX01 KWBC 061217
CHGHUR
TROPICAL CYCLONE GUIDANCE MESSAGE
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1217 UTC TUE OCT 6 2009

DISCLAIMER...NUMERICAL MODELS ARE SUBJECT TO LARGE ERRORS.
PLEASE REFER TO NHC OFFICIAL FORECASTS FOR TROPICAL CYCLONE
AND SUBTROPICAL CYCLONE INFORMATION.

ATLANTIC OBJECTIVE AIDS FOR

DISTURBANCE INVEST (AL912009) 20091006 1200 UTC

...00 HRS... ...12 HRS... ...24 HRS. .. ...36 HRS...
091006 1200 091007 0000 091007 1200 091008 0000

LAT LON LAT LON LAT LON LAT LON
BAMS 16.9N 51.8W 18.9N 54.9W 20.4N 57.5W 21.9N 59.3W
BAMD 16.9N 51.8W 18.6N 53.5W 20.3N 54.7W 21.8N 55.3W
BAMM 16.9N 51.8W 18.4N 54.3W 19.6N 56.3W 20.4N 57.7W
LBAR 16.9N 51.8W 19.1N 53.9W 21.5N 55.3W 23.5N 55.3W
SHIP 30KTS 29KTS 29KTS 29KTS
DSHP 30KTS 29KTS 29KTS 29KTS

...48 HRS... ...72 HRS... ...96 HRS. .. ..120 HRS...
091008 1200 091009 1200 091010 1200 091011 1200

LAT LON LAT LON LAT LON LAT LON
BAMS 23.1N 60.6W 25.1N 58.0W 24.1N 47.2W 27.6N 37.1W
BAMD 22.6N 55.6W 21.2N 53.8W 17.3N 54.8W 16.0N 57.7W
BAMM 20.8N 59.5W 20.3N 62.9W 18.3N 68.4W 17.2N 74.6W
LBAR 25.6N 53.8W 28.2N 45.6W 32.0N 37.4W 31.6N 23.1W
SHIP 26KTS 29KTS 39KTS 52KTS
DSHP 26KTS 29KTS 39KTS 51KTS

...INITIAL CONDITIONS...
LATCUR = 16.9N LONCUR = 51.8W DIRCUR = 305DEG SPDCUR = 20KT
LATM12 = 14.9N LONM12 = 48.3W DIRM12 = 300DEG SPDM12 = 22KT
LATM24 = 12.6N LONM24 = 45.5W
WNDCUR = 30KT RMAXWD = 45NM WNDM12 = 30KT
CENPRS = 1007MB OUTPRS = 1012MB OUTRAD = 120NM SDEPTH = M
RD34NE = 0NM RD34SE = 0NM RD34SW = 0NM RD34NW = 0NM

$$
NNNN

[HURAKAN]

Jeff Masters - http://www.wunderground.com/blog/JeffMa ... rynum=1341

A tropical wave (91L) near 17N, 52W, about 550 miles east of the Lesser Antilles Islands, continues to generate considerable heavy thunderstorm activity as it moves northwest at 15 mph. The wave is under high wind shear, 20 - 25 knots, and is over warm waters, 29°C. This morning's QuikSCAT pass showed no closed circulation, and top winds of 30 mph. However, satellite loops show that 91L now has a closed surface circulation, though strong upper-level winds out of the west are keeping the heavy thunderstorm activity confined to the east side of the center. Since there is not much dry air to the storm's west, the shear will not have as great a negative impact as we've seen in similar high-shear situations this year.

None of the computer models develop the wave, and they show moderate to high wind shear affecting 91L over the next 2 - 3 days. The storm will be steered northwest for the next 2 - 3 days by a trough of low pressure passing to the north. The northern Lesser Antilles may see some heavy rain showers and gusty winds from the southern portion of 91L on Thursday and Friday. By Friday, the trough will have passed far to the east, and high pressure will build in, which may force 91L to the southwest into the Caribbean, according to some model projections. Wind shear is expected to fall to the low to moderate range 3 - 5 days from now. If 91L holds together for the next 2 - 3 days and avoids interaction with the high mountains of Hispaniola late this week, the storm could be trouble. NHC is currently giving 91L a low (less than 30% chance) of developing into a tropical depression by Thursday, and the Hurricane Hunters are not on call to fly the storm. I think the storm has more potential to develop than NHC does, and put the odds of development over the next two days at medium (30 - 50%).

[HURAKAN]

Latest

[HURAKAN]

06/1145 UTC 16.9N 51.8W T1.0/1.0 91L -- Atlantic

No change. Dvorak matches Best Track

[Derek Ortt]

if it forms, it is out of here

CMC does develop this but shoots it straight north, then stalls it. Not enough ridging to drive this west

[Aric Dunn]

Its clearly a depression.. the nearby buoy is outside the small circulation and provides little help .. but its too late as the NHC will not upgrade with the upper environment getting worse. well its mostly that its moving into less favorable area had it not moved as far north over night it would be in a better area..