Vigorous Tropical Waves/Watching The Tropics

[srainhoutx]

Morning analysis across the Atlantic Tropical Basin indicates a tropical wave in the Bay of Campeche and another nearing the Lesser Antilles. Further East over Africa, another vigorous wave is about to emerge off the Coast of Africa and traverse the Atlantic in the mean easterly flow beneath the sub tropical upper ridge. The MJO pulse continues to look rather healthy arriving in early July and conditions may well become conducive for tropical development for any tropical wave nearing the Western Caribbean Sea and potentially the Gulf of Mexico.

[srainhoutx]

Sunday morning analysis across the Tropical Atlantic as well as Hemispheric Pattern features suggest a vigorous Tropical Wave has exited the African Coast into the far Eastern Atlantic. There is some noticeable spin associated with the wave, but convection has decreased as the Saharan Arid Layer (African Dust) and the strong sub tropical Atlantic Ridge indicates sinking air, or subsidence which is prohibitive of allowing thunderstorms to develop at this time. At the surface as well as via mimic imagery, the 'spin' is clearly evident and should arrive in the Caribbean Sea in about 8 -10 days which coincides with the arrival of a Convectively Coupled Kelvin Wave and MJO pulse which means rising air and greater instability could increase across the Western Caribbean Sea and the Gulf of Mexico. While the Global models do not indicate any potential tropical development at this time, past experience suggests when tropical waves interact with the CCKW and MJO pulse, the potential exists for tropical development as tropical thunderstorms can organize in a better environment of rising air and greater instability. The GFS Super Ensembles do indicate an Upper Air Pattern of a Desert SW Ridge and a trough in the East that may allow a weakness between those upper air features to be in place over portions of the NW and Northern Gulf Coast. As always, we can not fully trust the computer models beyond the 3 to 5 day period but the Hemispheric pattern is suggesting there may be some potential for tropical mischief in a couple of weeks. We will continue to monitor and update as need be.

[brooksgarner]

Great update, and I concur.

[tireman4]

As usual Srain, great update.

[srainhoutx]

Tuesday morning Tropical analysis suggest the strong sub tropical ridge and its subsidence across the Main Development Region (MDR) continues as a couple of tropical waves move West in the mean Easterly surface flow. There is a bit more convection noticed today along the Inter Tropical Convergence Zone (ITCZ) and additional tropical waves are moving across Africa near 10 degrees latitude. African Dust or SAL continues to inhibit an influence over the Central Atlantic, but there are some indications that the West African Monsoon Season may begin in the next week or so and may decrease that Dust. An excellent tool I use and some will find it helpful as well, is Polar Orbiting Satellite imagery that provides a 48 hour loop of the Northern Hemisphere and shows the various weather features across the Globe, North of the Equator.

http://climate.cod.edu/flanis/satellite ... olar-wv-48

In the Pacific, the MJO pulse continues to advances East over the Pacific Ocean along with a rather robust Convectively Couple Kelvin Wave (CCKW) and the Global models are beginning to indicate possible tropical development in the Eastern Pacific as those Hemispheric features near Mexico next week. Rising air and increased instability could allow for tropical thunderstorms to congeal and organize in the Eastern Pacific Basin that has had no Tropical Cyclones to date. Typically this is one of the most active Basins around the Globe for Tropical Cyclones, but in a neutral ENSO State potentially near a weak La Nina it is understandable that TC's have not been able to organize with the cooler waters increasing off the Western South America Pacific Coast and higher wind shear.

[srainhoutx]

This morning a Tropical Disturbance in the Eastern Pacific just West of Guatemala may organize into the 1st Eastern Pacific Tropical Cyclone of the 2016 Pacific Season. This is rather late and we typically see 1 to 3 storms have formed by this date and it likely is indicative of the approaching MJO Pulse and Convectively Coupled Kelvin Wave that has been mentioned for over a week. The GFS is very aggressive developing multiple areas of surfaces low pressure systems while the ECMWF is a bit less aggressive, but does indicate the possibility of a TC organizing. The NHC is currently giving the tropical disturbance a 60% chance for developing over the next 5 days as it moves slowly West to West North West.

The attachment 06292016 5AM PDT two_pac_5d0.png is no longer available

TROPICAL WEATHER OUTLOOK
NWS NATIONAL HURRICANE CENTER MIAMI FL
500 AM PDT WED JUN 29 2016

For the eastern North Pacific...east of 140 degrees west longitude:

1. A broad area of low pressure is expected to form south of the Gulf
of Tehuantepec later this week in association with a westward-moving
tropical wave that is currently located south of Guatemala.
Environmental conditions are forecast to be conducive for gradual
development of the disturbance, and a tropical depression could
form over the weekend while the system moves generally westward or
west-northwestward at 10 to 15 mph, remaining well offshore of the
coast of Mexico.
* Formation chance through 48 hours...low...near 0 percent
* Formation chance through 5 days...medium...60 percent

Forecaster Stewart


In the Atlantic Basin, a vigorous tropical wave is about midway between Africa and the Lesser Antilles, but lacks convection and is pushing a swath of dry air out in front of it. There is a bit of spin indicated by Mimic as it remains attached to the ITCZ heading West.

Further East toward Africa, additional tropical waves continue to move across Africa and the Eastern Atlantic that will need to be monitored in the days ahead as the MJO Pulse and CCKW move across the Atlantic Basin and may bring conditions more favorable for tropical development as we begin July and particularly in about 10 to 12 days.

[srainhoutx]

Tropical wave activity continues to increase across the Tropical Atlantic, but SAL or African Dust and subsidence from the Sub Tropical Atlantic Ridge continues to keep convection in check E of 50 degrees Longitude. There is a TUTT low spinning near the SE Bahamas inducing wind shear across the Caribbean Sea and that feature will keep any tropical waves from gaining convection throughout the weekend into next week.

The robust Madden Julian Oscillation (MJO) Pulse continues its slow trek Eastbound and will likely assist in developing a couple of Tropical Cyclones in the Eastern Pacific over the next week or so as they safely move generally West away from land into the open Pacific. The Convectively Coupled Kelvin Wave appears somewhat stronger this morning over the Eastern Pacific lending to greater rising air and instability which will further assist in TC Genesis in the Eastern Pacific Ocean. Eventually around the mid July timeframe, those Hemispheric features will move far enough East to begin impacting the Western Atlantic Basin. Some of the longer range ensemble computer guidance suggest the Upper Ridge will retreat West over the SW United States and pressures begin to fall across the NW Caribbean Sea and the Western Gulf. We will continue to monitor for any potential tropical troubles as we begin the slow, but steady march toward peak Hurricane Season 2016 and hope all have a Safe and Happy Independence Day!

[srainhoutx]

From Levi Cowan:

Levi Cowan ‏@TropicalTidbits · 28m28 minutes ago
GFS short-term correction is toward a more vigorous tropical wave to move through Lesser Antilles on Monday:

[Ounce]

As a side question, is it normal for High pressure to encompass the whole North Atlantic Ocean in the Summer?

[srainhoutx]

As a side question, is it normal for High pressure to encompass the whole North Atlantic Ocean in the Summer?

Different years and different Hemispheric Patterns that can be very complicated tend to factor into the strength of the Azores Ridge and its impact on our sensible weather. One of the visual tools that I use to show the causal weather observer is the Analogs which is basically a 'snapshot in time' of similar weather patterns that may offer clues to what we may experience when similar pattern of past years have occurred. Todays Day 11+ Analogs via the Global Forecasting System Super Ensembles (American Models and its individual ensemble Members) suggest 1979 is a good fit for today looking out a couple of weeks. These analogs vary daily, but are a good general snapshot in time of when Northern Hemispheric Patters were somewhat similar.

[hurricanetrack]

Greetings! Got an invitation to join up here so here I am! Been to Houston a lot these past few years doing some testing and other R&D work. The floods certainly kept us busy and have helped us to be ready for deploying our equipment this season and beyond. When and if the time comes for that, I will create a new thread about what we plan to do to cover a hurricane at landfall. The technology we have in place is astounding, especially compared to where we came from over the past decade or more. So for now, thought I would post a link to my video discussion for today. I produce these several times per week during the season and once per week during the off-season. They are on YouTube and populate our app, Hurricane Impact, for easy access on the go. It just so happens that today I began a new weekly segment called "this week in hurricane history". Hope you find the video discussion helpful - I'll post more as the season moves on.

Stay windy my friends!
Mark Sudduth - HurricaneTrack.com

https://youtu.be/fED50Q5oyds

[unome]

great to see you here, Mark ! I thoroughly enjoyed your "flood cams" earlier this year in Houston, and of course, the rest of your work

[srainhoutx]

Getting word that the latest Seasonal ECMWF Outlook not available to the public suggests about 11 named storms with near normal ACE and increased rainfall across the Tropical Atlantic during the August to November timeframe. Also the Tropical activity in the Pacific has led to some cooling of the sea surface temperatures suggesting the further decay of the Super El Nino as we transition toward a weak La Nina Global Hemispheric Pattern meaning less in the way of wind shear across the Atlantic Basin as peak season draws closer by the day.

Ryan Maue ‏@RyanMaue · 7h7 hours ago
Weekly change in SST nicely shows "Transequatorial Tropical Instability Waves" ... cooling in tropical EPAC

[srainhoutx]

While the Atlantic Basin is quiet and Saharan Dust continues to spread West across the Atlantic Ocean, we are beginning to see some potential changes as we end July and begin August. The very long Range Seasonal Guidance is suggesting the Eastern Pacific active period may relax and shift into the Atlantic Basin. Monsoonal activity across the Sahel Region of Africa where our Tropical Waves originate is forecast to become increasingly active and those Tropical Wave will continue to trek West in the mean Easterly flow beneath the Azores and Bermuda Ridge. With pressures remaining rather high across the Main Development Region, potential tropical development looks to remain in check across the Central Atlantic. The fly in the ointment is that it appears conditions across the Caribbean Sea, particularly the Western Caribbean will become increasingly favorable as mid/upper level wind shear relaxes, pressures begin to fall and the African Dust abates. Some of the very long range Ensembles are picking up on the potential favorable conditions suggesting Tropical Cyclone Genesis may be possible. With a rather strong Upper Ridge parked of the Central Plains, that tends to favor any tropical mischief to traverse West to WNW beneath the Ridge where we live. We will continue to monitor the trends as the month of July ends and we transition into August which is the beginning of our Hurricane Season 'Prime Time' and will update if we see any significant changes or potential threats.

[Ounce]

I guess that answers my question of how long it takes the atmosphere to get into a position to develop waves, when the dust stops coming off the Sahara...a week or two. Thanks.

[srainhoutx]

I guess that answers my question of how long it takes the atmosphere to get into a position to develop waves, when the dust stops coming off the Sahara...a week or two. Thanks.

There are some indications that the SAL Outbreak may relax in about 10 to 14 days. The 12Z GEFS Ensemble Members are 'sniffing' potential Tropical Cyclone Genesis in the NW Caribbean as the dust abates and mean sea level pressures begin to lower. We will see.

[srainhoutx]

A rather vigorous monsoonal low is existing the West African Coast this morning and appears to have a low and mid level spin as well as convection associated with the wave. While the Saharan Arid Layer is still and inhibiting factor, we often see a strong tropical wave work in tandem to eventually ease the African Dust that is typical in July. While no development is expect as it crosses the Central Atlantic, condition may become a bit more conducive for develop in about a week to 10 days as it enter the Caribbean Sea. Some of the longer range models have been suggesting possible Tropical Cyclone Genesis in the NW Caribbean Sea/Southern/Western Gulf during the later days of July. We will continue to monitor the Tropics in the Atlantic Basin as it appears the Eastern Pacific parade of Tropical Cyclones is about to ease and shut off as colder sea surface temperatures from upwelling and a suppressed Madden Julian Oscillation settles over the Central and Eastern Pacific.

[srainhoutx]

The overnight GFS 00Z and 06Z schemes are suggesting a very vigorous Tropical Wave emerging off the African Coast and slowly organizes into a Tropical Cyclone across the Central Atlantic. There are growing indications that a suppressed Convectively Coupled Kelvin Wave arrives in the Eastern Pacific shutting down the parade of EPAC tropical cyclones we have seen most of July. The Madden Julian Oscillation is currently in a wet phase across the Atlantic Basin and following a moderate bout of Saharan Dust emerging into the Atlantic Ocean next week, conditions may become a bit more favorable for Tropical Development particularly closer to 50W. We will continue monitoring the tropics for any mischief that may spin up as we end July and begin August when we start the march towards peak Hurricane Season that culminates around September 12th or so. Stay tuned.

[srainhoutx]

Michael Ventrice ‏@MJVentrice · 2m2 minutes ago
GEFS up to 60% now on MDR genesis.. ECMWF finally showing a 10% risk. It all comes down to how models handle AEWs




The Madden Julian Oscillation 200mb velocity schemes do suggest conducive conditions across Africa and the Indian Ocean where convective tropical waves organize and begin their trek West over Africa. The computer models may be 'sniffing' these enhanced conditions, so next week as we end July attention turns to our East. Tis that time of year folks... #ItOnlyTakesOne #HurricaneStrong

[DoctorMu]

Incubator in place: