Tropical Wave at Caribbean

[Sanibel]

This system has persistence in an area that has formed almost every system to show such tendencies in 2005.

Let's see if this is the exception.



Have to be careful. Alpha was wiped out by Wilma. So, this disturbance could end up being wiped out by Beta. OR - Beta could go inland and 91L could take up its moisture and energy...

[Brent]

11:30am TWO:

A TROPICAL WAVE IS SPREADING CLOUDINESS AND SHOWERS OVER THE LESSER
ANTILLES AND THE SOUTHEAST CARIBBEAN SEA...WITH THE MOST
CONCENTRATED ACTIVITY NEAR THE WINDWARD ISLANDS. THERE ARE NO
SIGNS OF TROPICAL CYCLONE FORMATION AT THIS TIME. HOWEVER...
UPPER-LEVEL WINDS ARE BECOMING A LITTLE MORE CONDUCIVE FOR GRADUAL
DEVELOPMENT AS THE WAVE MOVES WESTWARD INTO THE EASTERN CARIBBEAN
SEA.

Gamma???

[Ivanhater]

11:30am TWO:

A TROPICAL WAVE IS SPREADING CLOUDINESS AND SHOWERS OVER THE LESSER
ANTILLES AND THE SOUTHEAST CARIBBEAN SEA...WITH THE MOST
CONCENTRATED ACTIVITY NEAR THE WINDWARD ISLANDS. THERE ARE NO
SIGNS OF TROPICAL CYCLONE FORMATION AT THIS TIME. HOWEVER...
UPPER-LEVEL WINDS ARE BECOMING A LITTLE MORE CONDUCIVE FOR GRADUAL
DEVELOPMENT AS THE WAVE MOVES WESTWARD INTO THE EASTERN CARIBBEAN
SEA.
Gamma???

they all start out this way

[bvigal]

Update:
Pressure falls of 2 millibars in 24 hours reported in the Windward Islands with the wave passage. This is fairly significant since the developmental threshold is near 3 millibars. This proves the point that the wave is quite vigorous for this time of year and must be watched for near-term development.

Hyperstorm, you bring up a very interesting point. Which airport readings did you take? Was it a steady drop with no rise, or down and back up? Diurnal pressure variations of 3-4mb in 24hr period are quite normal in the tropics, so time of readings are important in order to determine actual trend. Typically, lowest readings are around 4am and 4pm, highest readings 10am and 10pm. It's always been difficult for me to see the actual passage of a wave due to this.

Also, average pressures vary by latitude and month:
Month 12N 15N 18N
Oct 1011.0 1013.0 1013.5
Nov 1011.0 1012.5 1013.5
Feb 1013.5 1014.5 1016.5
etc.

[Hyperstorm]

Update:
Pressure falls of 2 millibars in 24 hours reported in the Windward Islands with the wave passage. This is fairly significant since the developmental threshold is near 3 millibars. This proves the point that the wave is quite vigorous for this time of year and must be watched for near-term development.

Hyperstorm, you bring up a very interesting point. Which airport readings did you take? Was it a steady drop with no rise, or down and back up? Diurnal pressure variations of 3-4mb in 24hr period are quite normal in the tropics, so time of readings are important in order to determine actual trend. Typically, lowest readings are around 4am and 4pm, highest readings 10am and 10pm. It's always been difficult for me to see the actual passage of a wave due to this.

Also, average pressures vary by latitude and month:
Month 12N 15N 18N
Oct 1011.0 1013.0 1013.5
Nov 1011.0 1012.5 1013.5
Feb 1013.5 1014.5 1016.5
etc.

Bvigal...

More important than how low the pressures are/were at a certain time, you have to look at the differences in pressure at certain times. Even though the lowest pressures usually occur during the early morning and mid-afternoon hours, the differences in EXACTLY a 24 hour period is what counts.

For example, at 4 am yesterday morning in Martinique, the pressure was 1012 millibars. This morning, at 4 am the pressure was 1010 millibars. Even though that is generally the time with the lowest pressures anyway, you can see the difference is 2 millibars, which is not exactly what is expected. That was right around the time when the wave was passing through the area, so it is assumed that it was caused by the passage of the wave.

The same type of observations were reported in Dominica, Trinidad and Tobago and other nearby islands.

[bvigal]

Thank you, Hyperstorm! That's exactly what I was wanting to know.

[Hyperstorm]

Thank you, Hyperstorm! That's exactly what I was wanting to know.

You're welcome, Bvigal.

On another note, it appears that the wave axis has raced quickly westward and is now located just south of Puerto Rico. You can see the thunderstorm activity trying to re-flare back up in the form of a north/south line, very typical of a wave. This very quick movement has caused the wave to catch up with the retreating southwesterly flow ahead of it.

The environment is still forecast by the GFS to become very favorable starting tomorrow, but right now we're seeing a "status quo" in relation to the development of the wave.

[Ivanhater]

5:30


MOST CLOUDINESS AND SHOWERS ASSOCIATED WITH A TROPICAL WAVE HAVE
MOVED WESTWARD OVER THE SOUTHEASTERN CARIBBEAN SEA. THERE ARE NO
SIGNS OF TROPICAL CYCLONE FORMATION AT THIS TIME. HOWEVER...
UPPER-LEVEL WINDS ARE EXPECTED TO BECOME A LITTLE MORE CONDUCIVE FOR
DEVELOPMENT AS THE WAVE MOVES WESTWARD INTO THE CENTRAL AND WESTERN
CARIBBEAN SEA.

[skysummit]

Holy POO....Gamma on the horizon.

[Coredesat]

10:30 TWO should be up shortly.

[arkess7]

Thank you, Hyperstorm! That's exactly what I was wanting to know.

uhhh thanks for your avatar.........i know its true but it freaks me out!!! just makes me more aware

[cycloneye]

I changed the title of thread as no models haved been running for this system for more than 24 hours.

[Brent]

10:30pm TWO:

CLOUDINESS AND SHOWERS ASSOCIATED WITH A TROPICAL WAVE OVER THE
EASTERN CARIBBEAN SEA HAVE DIMINISHED. IT APPEARS THAT THE CHANCES
FOR DEVELOPMENT HAVE ALSO DISMINISHED.

[krysof]

Tropical Weather Outlook


Statement as of 10:30 PM EDT on October 27, 2005


10:30 TWO

Cloudiness and showers associated with a tropical wave over the
eastern Caribbean Sea have diminished. It appears that the chances
for development have also disminished.
Elsewhere...tropical storm formation is not expected through
Saturday.
Forecaster Avila
$$

Chances are gone for Gamma.

[cycloneye]

[tampaflwx]

CLOUDINESS AND SHOWERS ASSOCIATED WITH A TROPICAL WAVE OVER THE
EASTERN CARIBBEAN SEA HAVE DIMINISHED. IT APPEARS THAT THE CHANCES
FOR DEVELOPMENT HAVE ALSO DISMINISHED.

Just an interesting little tidbit....At first glance it may seem like Disminished is just a typo. However, I think that particular spelling mistake stems from the fact that Forecaster Lixion Avila, the only hispano forecaster with the NHC, wrote that. The verb To diminish is Disminuir in spanish, so that's probably why Avila put the extra 's' in there

[cycloneye]

000
ABNT20 KNHC 280920
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 AM EDT FRI OCT 28 2005

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

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM BETA... LOCATED IN THE SOUTHWESTERN CARIBBEAN SEA ABOUT
35 MILES EAST-SOUTHEAST OF SAN ANDRES ISLAND.

CLOUDINESS AND SHOWERS ASSOCIATED WITH A TROPICAL WAVE OVER THE
EASTERN CARIBBEAN SEA HAVE INCREASED THIS MORNING. HOWEVER... ALL OR
A PORTION OF THIS WAVE WILL LIKELY BECOME ABSORBED BY TROPICAL
STORM BETA... WHICH WILL DECREASE THE POTENTIAL FOR ANY TROPICAL
CYCLONE DEVELOPMENT.

ELSEWHERE...TROPICAL STORM FORMATION IS NOT EXPECTED THROUGH
SATURDAY.

FORECASTER STEWART


5:30 AM TWO

It will be very interesting to see what kind of interaction Beta and the wave will have.

[caneman]

000
ABNT20 KNHC 280920
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 AM EDT FRI OCT 28 2005

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

THE NATIONAL HURRICANE CENTER IS ISSUING ADVISORIES ON TROPICAL
STORM BETA... LOCATED IN THE SOUTHWESTERN CARIBBEAN SEA ABOUT
35 MILES EAST-SOUTHEAST OF SAN ANDRES ISLAND.

CLOUDINESS AND SHOWERS ASSOCIATED WITH A TROPICAL WAVE OVER THE
EASTERN CARIBBEAN SEA HAVE INCREASED THIS MORNING. HOWEVER... ALL OR
A PORTION OF THIS WAVE WILL LIKELY BECOME ABSORBED BY TROPICAL
STORM BETA... WHICH WILL DECREASE THE POTENTIAL FOR ANY TROPICAL
CYCLONE DEVELOPMENT.

ELSEWHERE...TROPICAL STORM FORMATION IS NOT EXPECTED THROUGH
SATURDAY.

FORECASTER STEWART


5:30 AM TWO

It will be very interesting to see what kind of interaction Beta and the wave will have.

This wave is looking very healthy and apparantly has a MLC!

[Hyperstorm]

Satellite imagery indicates that there is northerly flow that is impeding any developing from this wave. The GFS was forecasting an upper-level high developing near Dominican Republic and Puerto Rico by this time and that has not yet materialized. As long as we have that northerly flow, it won't develop regardless of a MLC or surface circulation.

On the other hand, I honestly don't think that it will be absorbed by Beta like the outlook mentions. Beta is a very small tropical cyclone that is located in the extreme SW Caribbean Sea well away from this feature. In fact, the tropical wave NE of Beta is the one that very well could interact with Invest 91L and cause an explosion of thunderstorms. Usually, those types of interactions with troughs and waves creates development (pending favorable conditions).

Watch for any signs of outflow developing...

EDIT: THE UPPER HIGH DID DEVELOP JUST SOUTH OF HISPANIOLA AND PUERTO RICO LAST NIGHT, BUT IT IS MOVING WESTWARD WITH ITS CENTER NOW NEAR THE COAST OF HISPANIOLA. This faster westward movement has left Invest 91L on its northerly flow. The high is forecast to move toward the western Caribbean in a few days, so development potential is still there, if it manages to develop a better structure.

[Wacahootaman]

Mighty high cloud tops in the IR pic this morning!

Including some of those black IR signatures.