Friday, July 7, 2017

DEPRESSION DEGENERATES TO AN OPEN WAVE LAST POST ON THIS SYSTEM

JULY 7, 2017 0500 PM EDT

TROPICAL DEPRESSION FOUR DEGENERATES INTO AN OPEN TROPICAL WAVE ONCE AGAIN.  DRY AIR AND FAST FORWARD MOTION DID THIS SYSTEM IN.  THIS WILL BE THE LAST POST ON THIS WEATHER SYSTEM UNLESS REGENERATION OCCURS.

RTW  http://ralphstropicalweather.myfreesites.net








TROPICAL WEATHER OUTLOOK JULY 7, 2017 1215 PM EDT

Tropical Wave # 1 west of the African Coast has a lot of dry air and Sahara dust intruding into the surrounding of this wave.  This minimizes the development of thunderstorms along the northern axis of the wave.  However there seems to be some thunderstorms along the southern axis of the wave at present.

Tropical Wave # 2 over the East Caribbean is also encountering dry air, Sahara dust and wind shear.  The likelihood of development is not likely at this. time

Tropical Wave# 3 is is encountering wind shear and this wave is moving over the Yucatan.

Elsewhere tropical cyclone formation is not expected for the next couple of days.  I will be monitoring to coast of Africa next week for another possible strong wave.

RTW  http://ralphstropicalweather.myfreesites.net


TROPICAL DEPRESSION 4 JULY 7, 2017 1051 AM EDT

Tropical Depression 4 is still moving too fast and is presently still moving through dry air.  Neither of these conditions are favorable for this system to continue to develop.  More than likely this system will have to be downgraded to an open wave as it continues to track toward the west-northwest.

I am working on the Tropical Weather Outlook maps and should have it posted here within an hour or so.  Sorry for the inconvenience its just me doing all this.
 RTW





Thursday, July 6, 2017

TROPICAL DEPRESSION 4 UPDATE JULY 6 2017 0500 PM EDT

As of 0500 PM EDT Tropical Depression Four remains disorganized as it tracks through dry air and speeds across the Atlantic near 23 mph forward speed.  This speed for tropical cyclone does not help in the development process and the storm produces its own wind shear of over the cloud structure.

The depression is tracking almost due west, however, according to 18z model XTRP the direction of travel is west of due north while the Invest previous and present track is directly westward.

Not much change is expected unless it slows down but that does not look likely, as a 1029 mb High pressure system near 35° N. Long. and 35° W. Lat. is helping to steer this system quickly across the Central Atlantic.

Remember what I mentioned yesterday a weak system always tends to track west to west-northwest. A tropical cyclones path are governed by trough and low pressure weakening the High pressures ridge.  As the High pressure ridge is weaken it opens a passage way for a well organized tropical cyclone to move into.  However, in the case of an Andrew storm the High pressure got stronger and the ridge built westward over the cyclone strengthening it and turning it westward.  There was no strong low pressure system or trough to prevent that westward track.  So this depression could remain on the westward or west-northwest track until it weakens further and dissipates.

RTW  http://ralphstropicalweather.myfreesites.net 







TROPICAL WEATHER OUTLOOK JULY 6, 2017 0416 PM EDT

Other than weak tropical depression four the tropical Atlantic remains quiet for now.  Sahara dust and dry air over off the African coast affecting wave number one and wave number three is also being affected by dry and African dust that has made its way toward the Lesser Antilles.  This dry air limits the development of thunderstorms along these waves axis.  Some wind shear is also present over the west Caribbean that is also affecting tropical wave number 4.  Elsewhere all remains quiet.

I will have an update on TD Four as soon as the data is released.

RTW http://ralphstropicalweather.myfreesites.net

TROPICAL UPDATE JULY 6, 2017 1100 AM EDT

RTW:  Ralph's Tropical Weather
TROPICAL DEPRESSION FOUR LOOKING ILL DEFINE THIS MORNING.  MOST OF THE CONVECTION (THUNDERSTORMS) HAVE DIMINISHED.  


THE DEPRESSION IS MOVING THROUGH DRY AIR AND IS PRESENTLY MOVING TO FAST 21 MPH FORWARD SPEED.  

THIS PRODUCES SHEAR OVER THE THUNDERSTORMS AND THEY BEGIN TO LOSE THEIR INTENSITY.  ON VISIBLE SATELLITE YOU CAN SEE FEATHERING OF THE CLOUD SURROUNDING THE DEPRESSION.  THAT IS WIND SHEAR OVER THE STORM.

IF THIS TREND CONTINUES IT MAY HAVE TO BE DOWNGRADED TO AN OPEN WAVE AGAIN...RTW

http://ralphstropicalweather.myfreesites.net 






Wednesday, July 5, 2017

TOMORROW'S THUNDERSTORM OUTLOOK

3
Tomorrow's Severe Thunderstorm Outlook.


TROPICAL WEATHER UPDATE JULY 5, 2017 04:14 PM EDT

RTW:

The center of circulation of 94L is remains exposed to the right of the convection (thunderstorms) ahead of the low level circulation.  Most of the models keep this system weak and some even show it diminishing as it nears the Eastern Bahamas.  This system has its own moisture surrounding the low but there is a wide area of dry air that this system has to track through and moderate easterly shear is also affecting the low/wave.  It still has a chance for development before it runs into a more unfavorable environment.  As for the track a weak system will tend to track west-to a west-northwest.  However, this system has been generally tracking toward the northwest per model and past position/track issued for this invest during each model run.  Some models still have that left bias and once again this could be that the Atlantic high will build westward in time or we will be dealing with a weak disorganized system that will not be influenced by any troughs moving off the east coast... Stay tuned here daily for the latest update on 94L.

Ralph's Tropical Weather RTW  http://ralphstropicalweather.myfreesites.net










12z MODEL RUN IS OUT JULY 5, 2017 01:39 PM EDT

RTW:
The 12z model run is out and there is still a leftward bias on most of the tracks.  however, we don't have a well developed system, and its still to far out in the Atlantic to get tight accurate run.

So far this system is struggling with some moderate easterly shear between 36° and 45° west Latitude.  There is also dry air between 40° and 60° west Latitude that this system will have to deal with.  However, the Low seems to be surrounded by its own moisture, so some slow development is possible as this system begins tracking to the west-northwest.  94L has been tracking mainly toward the northwest.

0200 PM EDT UPDATE from NHC
NHC drops probability for development, see below.
* Formation chance through 48 hours...medium...60 percent
* Formation chance through 5 days...medium...60 percent

Ralph's Tropical Weather RTW


TODAY'S THUNDERSTORM OUTLOOK

30
Today's Updated Thunderstorm Outlook.


TROPICAL WEATHER OUTLOOK JULY 5, 2017 1057 AM EDT


RTW:
There is an area of showers  with a small nucleus of colder cloud tops where the stronger storms are located ahead of the Low Level Circulation (LLC).  If this circulation can manage to catch up with the convectiom (thunderstorms) then we will see a depression form later today or tomorrow. Most of the models are still suggesting a weak system although intensity models say a tropical storm.  According to atmospherirc data the conditions ahead of this system will become unfavorable in the coming days and this could be what the models are suggesting.  I will keep you posted.  http://ralphstropicalweather.myfreesites.net

  
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NATIONAL HURRICANE CENTER


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