Tropical Tidbits from the Tundra

Chantal, 99L, and potential rabbits

By: Levi32, 4:29 PM GMT on July 31, 2007

Afternoon Update on 99L:

99L is at the very best holding steady, but the circulation now looks very ragged and more like part of the ITCZ than an invest. After looking up the MJO today I saw that there is a huge downward motion pulse in the western Atlantic/Caribbean that is a graveyard for any tropical system right now. Until we move back into an upward motion pulse in 1-2 weeks we shouldn't expect a lot of developments. Unless 99L can pull a miracle during the diurnal max tonight...it's probably dead. Next wave in line probably dead as well as its too far south, and the next one after that just came off Africa and should be watched, although the outcome will probably be the same as the other 20 waves that have come off this season.


Morning Update:
Well TD 3 beat all odds and was upgraded to TS Chantal today with 50mph winds. In reality this is a sub-tropical storm not tropical because on satellite you can clearly see a warm front and a cold front, showing that there is obviously a lot of extratropical influence. Chantal is no threat to anyone except shipping lanes, and should move across the north Atlantic as a strong extratropical low for the next few days.

99L isn't feeling that good, and after attempting a comeback last night during the diurnal max, convection has once again all but completely died this morning due to dry air. The latest QuikScat pass is 7 hours old, but it shows a poorly defined elongated circulation which is still partially embedded in the ITCZ. I don't think we will see anything come from 99L today, as the dry air will continue to choke off any convection that tries to form. However with enough time, if it survives, the system could be a threat to develop once it's in the Caribbean, where the dry air will slack off a little bit. Wind shear remains favorable, although it is forecasted to increase slightly in the central Caribbean.

None of the models are really developing this system, but it is really hard to pick up because of how weak and small it is. Right now I think the only thing 99L really needs is a well-developed surface circulation. If it can get that, then it would probably be able to survive while these intermittent bursts of convection slowly moisten the atmosphere around it. The next QuikScat pass will be interesting to see if 99L was able to do any reorganization overnight. Bottom line, this thing still needs to be watched, and will be around for a long while before it develops.

In the rest of the Atlantic we still may have a few surprises popping out of the hat. Actually they're called rabbits in the Meteorology world, but I won't get into that now. An old but vigorous cold front coming off the SE coast is spawning deep thunderstorms in the NE Gulf of Mexico and off the Carolinas. Both these areas have potential to slowly develop over the next couple days. The area off the Carolinas has the most potential, but will be no threat to land even if something comes out of it. Something else worthy of attention is yet another new wave emerging off the coast of Africa as we speak. Convection is impressive at the moment, but as usually happens will probably die off as it moves over water. What I find interesting though is that this wave is very large, and is the farthest north we have seen a wave come off this year. It is actually at the latitude of the Cape Verde Islands, making it a true Cape Verde wave. The higher latitude position of this wave gives it a huge edge over the waves before it in being able to develop. Only time will tell, but the African wave train will start heating up really soon.

We shall see what happens!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 000
ABNT20 KNHC 311543
TWOAT

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1130 AM EDT TUE JUL 31 2007

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

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON RECENTLY
UPGRADED TROPICAL STORM CHANTAL...LOCATED ABOUT 305 MILES SOUTH OF
HALIFAX NOVA SCOTIA.

A WEAK AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS
CENTERED ABOUT 600 MILES EAST OF THE SOUTHERN WINDWARD ISLANDS AND
IS MOVING WESTWARD AROUND 10 TO 15 MPH. ALTHOUGH THIS SYSTEM HAS
BECOME LESS ORGANIZED OVER THE PAST FEW HOURS...IT STILL HAS THE
POTENTIAL TO BECOME A TROPICAL DEPRESSION DURING THE NEXT COUPLE OF
DAYS.

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

PUBLIC ADVISORIES ON TROPICAL STORM CHANTAL ARE ISSUED UNDER WMO
HEADER WTNT33 AND UNDER AWIPS HEADER MIATCPAT3. FORECAST/ADVISORIES
ON TROPICAL STORM CHANTAL ARE ISSUED UNDER WMO HEADER WTNT23 AND
UNDER AWIPS HEADER MIATCMAT3.

$$
FORECASTER BLAKE~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

^Click for Loop^



^Click for Loop^




~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NASA zoomed-in visible loop of 99L

Model tracks for 99L

Model intensity forecasts for 99L


SSD Dvorak Intensity Estimates

CIMSS Dvorak Intensity Estimates

SSD tropical formation probability and other maps

CIMSS satellite derived winds and analysis

Atlantic Models

Navy Tropical Cyclone Page

National Hurricane Center


NASA High-resolution GOES Satellite Imagery


CIMSS Saharan Air Layer Analysis

METEOSAT Satellite Imagery (Updated every hour)

North Atlantic WV Loop (The Big Picture)

Updated: 8:02 PM GMT on July 31, 2007

Permalink

Chantal, 99L, and potential rabbits

By: Levi32, 4:28 PM GMT on July 31, 2007

Well TD 3 beat all odds and was upgraded to TS Chantal today with 50mph winds. In reality this is a sub-tropical storm not tropical because on satellite you can clearly see a warm front and a cold front, showing that there is obviously a lot of extratropical influence. Chantal is no threat to anyone except shipping lanes, and should move across the north Atlantic as a strong extratropical low for the next few days.

99L isn't feeling that good, and after attempting a comeback last night during the diurnal max, convection has once again all but completely died this morning due to dry air. The latest QuikScat pass is 7 hours old, but it shows a poorly defined elongated circulation which is still partially embedded in the ITCZ. I don't think we will see anything come from 99L today, as the dry air will continue to choke off any convection that tries to form. However with enough time, if it survives, the system could be a threat to develop once it's in the Caribbean, where the dry air will slack off a little bit. Wind shear remains favorable, although it is forecasted to increase slightly in the central Caribbean.

None of the models are really developing this system, but it is really hard to pick up because of how weak and small it is. Right now I think the only thing 99L really needs is a well-developed surface circulation. If it can get that, then it would probably be able to survive while these intermittent bursts of convection slowly moisten the atmosphere around it. The next QuikScat pass will be interesting to see if 99L was able to do any reorganization overnight. Bottom line, this thing still needs to be watched, and will be around for a long while before it develops.

In the rest of the Atlantic we still may have a few surprises popping out of the hat. Actually they're called rabbits in the Meteorology world, but I won't get into that now. An old but vigorous cold front coming off the SE coast is spawning deep thunderstorms in the NE Gulf of Mexico and off the Carolinas. Both these areas have potential to slowly develop over the next couple days. The area off the Carolinas has the most potential, but will be no threat to land even if something comes out of it. Something else worthy of attention is yet another new wave emerging off the coast of Africa as we speak. Convection is impressive at the moment, but as usually happens will probably die off as it moves over water. What I find interesting though is that this wave is very large, and is the farthest north we have seen a wave come off this year. It is actually at the latitude of the Cape Verde Islands, making it a true Cape Verde wave. The higher latitude position of this wave gives it a huge edge over the waves before it in being able to develop. Only time will tell, but the African wave train will start heating up really soon.

We shall see what happens!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 000
ABNT20 KNHC 311543
TWOAT

TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1130 AM EDT TUE JUL 31 2007

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

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON RECENTLY
UPGRADED TROPICAL STORM CHANTAL...LOCATED ABOUT 305 MILES SOUTH OF
HALIFAX NOVA SCOTIA.

A WEAK AREA OF LOW PRESSURE ASSOCIATED WITH A TROPICAL WAVE IS
CENTERED ABOUT 600 MILES EAST OF THE SOUTHERN WINDWARD ISLANDS AND
IS MOVING WESTWARD AROUND 10 TO 15 MPH. ALTHOUGH THIS SYSTEM HAS
BECOME LESS ORGANIZED OVER THE PAST FEW HOURS...IT STILL HAS THE
POTENTIAL TO BECOME A TROPICAL DEPRESSION DURING THE NEXT COUPLE OF
DAYS.

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

PUBLIC ADVISORIES ON TROPICAL STORM CHANTAL ARE ISSUED UNDER WMO
HEADER WTNT33 AND UNDER AWIPS HEADER MIATCPAT3. FORECAST/ADVISORIES
ON TROPICAL STORM CHANTAL ARE ISSUED UNDER WMO HEADER WTNT23 AND
UNDER AWIPS HEADER MIATCMAT3.

$$
FORECASTER BLAKE~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

^Click for Loop^



^Click for Loop^




~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NASA zoomed-in visible loop of 99L

Model tracks for 99L

Model intensity forecasts for 99L


SSD Dvorak Intensity Estimates

CIMSS Dvorak Intensity Estimates

SSD tropical formation probability and other maps

CIMSS satellite derived winds and analysis

Atlantic Models

Navy Tropical Cyclone Page

National Hurricane Center


NASA High-resolution GOES Satellite Imagery


CIMSS Saharan Air Layer Analysis

METEOSAT Satellite Imagery (Updated every hour)

North Atlantic WV Loop (The Big Picture)

Permalink

Invest 99L a threat to develop

By: Levi32, 3:04 PM GMT on July 30, 2007

Hey guys. Been a while lol. Sorry I haven't been here but I've been pretty busy and my mom is having major major eye surgery tomorrow so things are a little stressful around here. But I always come back when a storm is brewing :)

This morning our little wave in the central Atlantic has decided to rear its head, and has been designated 99L. The primary reason for this is probably the increase in convection and the development of a possible surface circulation overnight. The latest QuikScat scan hasn't come in yet, but visible loops definitely show west winds at the surface in the southern semi-circle. Convection isn't all that impressive due to dry air in the area, but it's the most intense we've seen with a wave this far west all year, and there are already signs of upper-level outflow trying to establish itself.

The central Atlantic west of 40w has been the graveyard for most African waves this season. This is due to a large amount of dry air that has been hanging around that area for several weeks. 99L has a lot of this dry air to overcome before reaching the central Caribbean, which is where its present course is taking it. Convection with the system has decreased in intensity over the past couple hours, but the moisture shield is spreading slowly northward, and I think the wave has a fighting chance to survive the dry air if it continues to look this healthy. The wave is also moving into an area of 0-10 knot shear, increasing its chances significantly. This system is not in a situation where it can organize rapidly because of dry air, but all else looks good and slow development should progress. The major models have not yet initialized the system on the 6z runs, but they should have it on the 12z and 18z runs, which will be very interesting to look at. The strong upper ridge over the central Atlantic should steer this into the central Caribbean before it makes any move north. Bottom line is that this has the potential to become TD #3 sometime tomorrow, and is something to be watched intently over the coming days.

To coin a phrase: "ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE NEXT 48 HOURS."

We shall see what happens!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 000
ABNT20 KNHC 301501
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1130 AM EDT MON JUL 30 2007

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

SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH A LOW PRESSURE AREA
CENTERED ABOUT 175 MILES WEST-NORTHWEST OF BERMUDA HAS BECOME
BETTER ORGANIZED THIS MORNING. ENVIRONMENTAL CONDITIONS ARE ONLY
MARGINALLY FAVORABLE FOR SIGNIFICANT DEVELOPMENT. HOWEVER...THE
SYSTEM COULD BECOME A TROPICAL OR SUBTROPICAL CYCLONE BEFORE
MERGING WITH A FRONTAL BOUNDARY IN A COUPLE OF DAYS AS IT MOVES
NORTHEASTWARD AROUND 15 MPH.

AN AREA OF CLOUDINESS AND SHOWERS LOCATED ABOUT 950 MILES EAST OF
THE SOUTHERN WINDWARD ISLANDS IS ASSOCIATED WITH A WESTWARD-MOVING
TROPICAL WAVE. THIS AREA SHOWS SIGNS OF ORGANIZATION...AND SOME
SLOW DEVELOPMENT OF THIS SYSTEM IS POSSIBLE DURING THE NEXT COUPLE
OF DAYS.

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

$$
FORECASTER BROWN/PASCH ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

^Click for Loop^



^Click for Loop^




~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NASA zoomed-in visible loop of 99L

Model tracks for 99L

Model intensity forecasts for 99L


SSD Dvorak Intensity Estimates

CIMSS Dvorak Intensity Estimates

SSD tropical formation probability and other maps

CIMSS satellite derived winds and analysis

Atlantic Models

Navy Tropical Cyclone Page

National Hurricane Center


NASA High-resolution GOES Satellite Imagery


CIMSS Saharan Air Layer Analysis

METEOSAT Satellite Imagery (Updated every hour)

North Atlantic WV Loop (The Big Picture)

Updated: 3:33 PM GMT on July 30, 2007

Permalink

About Levi32

Levi Cowan has been tracking tropical systems since 2002, and is currently working on his bachelor's degree in physics at UAF.

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