Monitoring Tropical Wave And Latest On TD 4

Tropical Depression 4 has weakened and is no longer a tropical cyclone according to the National Hurricane Center (NHC). The system is now an open wave, but still has convection associated with the wave. The appearance on visible satellite imagery is not impressive at the moment, and Firsthand Weather is not expecting tropical cyclone development with this system for now.

Visible Satellite Imagery (Remnants of TD 4)

The next wave worth monitoring is is off of the western African coast. This wave is supported by numerical guidance to potentially undergo tropical development this upcoming week.

Visible Satellite Imagery (New Tropical Wave)

So why is this tropical wave seeing support from numerical guidance? The wave is in an environment that is conducive for slow tropical cyclone development. The latest vorticity map shows the tropical wave is beginning to show some environmental spin. This is needed for tropicalgenesis.

Current 850mp Vorticity Map (University of Wisconsin)

The latest numerical guidance is indicating this vocticity will continue to increase and become more symmetrical with time as the wave moves towards the WNW. The latest GFS (12Z) shows the environmental spin becoming well-defined by Wednesday.

Future (Wednesday) 850mp Vorticity Map (Tropical Tidbits)

This looks plausible based on the current atmospheric conditions the wave is encountering. The wave is in a moist environment with low environmental shear. Numerical guidance indicates the environmental will remain relatively favorable for organization over the next several days.

Current Environmental Wind Shear Map (University of Wisconsin)

Saharan Air Layer Map (University of Wisconsin)

As the tropical wave moves towards the WNW, the system needs to be monitored as tropical cyclone development is plausible. The general WNW motion is likely due to the strong ridge north of the system. This would potentially place the Lesser Antilles in a favorable geographical area to see impacts by the upcoming weekend. The latest GFS (12Z) shows the wave developing into a tropical cyclone, impacting the islands, and moving into the Caribbean by the weekend.

Future (Saturday) 850mp Vorticity Map (Tropical Tidbits)

It is too early to determine the strength and final movement of this system, but Firsthand Weather will continue to monitor this evolving forecast. Keep checking back for updates.

9 Billion Dollar Climate Events And 2nd Warmest YTD On Record For U.S.

The latest climate report from the National Oceanic and Atmospheric Administration (NOAA) says this is the United States’ 2nd warmest year to date (see full report and article here). The warmest temperatures to date have been marked by a growing drought in the Northern Plains, and severe heat and wildfires in the Southwest.

June has been impressive when looking at the month quantitatively. 70.3 degrees Fahrenheit was the average temperature for the continental United States. Most people at this point are probably thinking “well, isn’t June supposed to be warm?” Yes, but 70.3 degrees Fahrenheit is 1.9 degrees Fahrenheit above average (20th Century). This makes June of 2017 the 20th warmest June on record.

Even more eye-opening is the year to date numbers. 50.9 degrees Fahrenheit is the average temperature for the continental United States. This is a staggering 3.4 degrees Fahrenheit above average (20th Century). This makes January-June, 2017, the second warmest first-half of the year on record.

Mean Temperature Departure From Average: YTD (NOAA)

Not only is the year-to-date temperature the second warmest in the 20th-Century records, there have been several noteworthy climate events that have occurred in the United States. The United States experienced 9 billion dollar weather and climate disasters. This period trails only 2011 and 2016 when 10 billion dollar events occurred from January through June.

June 2017 Notable Climate Events (NOAA)

The numbers and figures in this article are directly from NOAA. Again, to see their report click here.

Tropical Depression 4 struggling in the Atlantic

Tropical Depression 4 formed last night after a major burst of convection, seen on the satellite image below.  This convection, while strong at the time, has weakened and the low level circulation has gradually weakened throughout this morning and early afternoon.   Some additional increase in strength is expected but Firsthand Weather does not anticipate that TD Four will become a Tropical Storm at this time.

Regional Conditions in the Tropics

Currently, dry air from an earlier Saharan Air Layer continues to be in place over the Atlantic as seen on the Water Vapor image above.  The entrainment of this dry air continues to be the biggest prohibiting factor preventing Tropical Depression 4 from increased development.  As Chris had forecast in his previous article, other conditions  are currently conducive for tropical development at this time, but wind shear is expected to increase as Tropical Depression 4 moves north of the Lesser Antillies.  This will cause the depression to weaken into a Post Tropical Cyclone and dissipate before reaching the coast of the United States.

Tropical Depression 4 Expected Track and Model Analysis

At this time, Tropical Depression 4 is moving West-Northwest around 21 mile per hour.  This track is expected to continue for then next couple of days as Tropical Depression 4 moves just north of the Lesser Antillies.  4 should then continue on that general heading until dissipation to the Northeast of the Bahamas.

Tropical depression 4

 

The latest GFS model, show below, does show some marginal strengthening in the short  term, and the forecast calls  for maximum sustained winds  to reach 35 miles per hour, but beyond the next day or 2, conditions become unfavorable and the Tropical depression quickly comes apart as shown in the second image.

As seen in this second image, the weakening system begins to dissipate while North of Puerto Rico and then completely dissipates in later images.

Rob

 

 

Severe Storms Possible This Afternoon-Tonight

Severe thunderstorms are possible across much of Oklahoma and northern Texas this afternoon–continuing through the overnight hours. Many of the local lakes and camping areas are packed with people celebrating the holiday, so it will be important to remain alert throughout the rest of today. The region was heavily impacted by severe storms yesterday. Wind damage was common across Oklahoma and northern Texas. Here is a look at the severe weather reports from yesterday.

Storm Reports From Yesterday (Storm Prediction Center: SPC)

These same areas will see severe thunderstorms again this evening. The SPC has a slight risk of severe thunderstorms for much of Oklahoma and northwestern Texas. There is even an enhanced risk for much of western Oklahoma and far northwestern Texas.

SPC Thunderstorm Outlook For Today-Overnight

The main threat is damaging wind. This threat will be enhanced as a thunderstorm complex evolves and rapidly advances southward. Winds associated with this thunderstorm complex may exceed 70mph. A secondary threat is large hail. This is why the SPC has a Severe Thunderstorm Watch through 11:00PM CDT.

Severe Thunderstorm Watch In Place (SPC)

It is possible this watch may be extended further southeast with time. Latest high-resolution short-range models are showing the thunderstorm complex that is currently developing in northwestern Oklahoma will advance through most of Oklahoma and northern Texas.

Future Radar Early Morning (3km NAM)

Please remain alert if you’re camping tonight. Damaging wind is not the only threat. Frequent cloud to ground lighting and flash flooding is possible for all of Oklahoma and northern Texas.

Tropics Brewing!!

Firsthand Weather is still monitoring the strong tropical wave in the eastern Atlantic (see Firsthand Weather’s first article regarding the wave and explanation of what an African Easterly Wave is HERE!). The National Hurricane Center (NHC) has now given this wave a 50% chance of development into a tropical cyclone (tropical depression or tropical storm) within the next five days.

NHC Monitoring Area For Tropical Development

Firsthand Weather is not concerned about rapid development, but a more gradual development over the next several days is plausible. The wave still does not have the best presence on satellite, and lacks deep, organized convection.

Current Satellite View

This will likely change beyond 48-72 hours since the wave is in an environment conducive for convection to slowly organize and deepen. This environment is characterized by relatively low environmental shear and above normal moisture.

GFS Shear Map (Current)

GFS Moisture Map (Current)

The favorable environmental conditions should persist as the wave moves towards the west over the next few days. This will increase the chances of tropical cyclone development by late in the week. By Saturday, the system will begin more of a west-northwest motion as it approaches the Lesser Antilles. Beyond this upcoming weekend is when the numerical guidance begins differing, and shows slightly different synoptic patterns. It is too early to determine the synoptic pattern, which will influence the track of this wave (or tropical cyclone at this point if it develops); and, the numerical guidance is not of much help with the synoptic pattern this far out.

GFS 500mb Map (Wednesday; July 12th)

Canadian 500mb Map (Wednesday; July 12th)

European 500mb Map (Tuesday; July 11th)

It appears a trough will dig into the central/eastern United States around this time-frame (mid-next week–not this upcoming week). Depending on the exact placement and strength of this trough, the strength of the potential tropical cyclone, and the placement of the Bermuda high will play large factors in the movement of this system. Again, the numerical guidance is handling these features differently, which is why they’re forecasting different tracks. It is too early to say if the United States is in the all clear or if there will be impacts. Firsthand Weather will continue to keep an eye on this wave, so keep checking back frequently for updates as confidence begins to increase.

Tropics Brewing!

Firsthand Weather is still monitoring the strong tropical wave in the eastern Atlantic (see Firsthand Weather’s first article regarding the wave and explanation of what an African Easterly Wave is HERE!). The National Hurricane Center (NHC) has now given this wave a 50% chance of development into a tropical cyclone (tropical depression or tropical storm) within the next five days.

NHC Monitoring Area For Tropical Development

Firsthand Weather is not concerned about rapid development, but a more gradual development over the next several days is plausible. The wave still does not have the best presence on satellite, and lacks deep, organized convection.

Current Satellite View

This will likely change beyond 48-72 hours since the wave is in an environment conducive for convection to slowly organize and deepen. This environment is characterized by relatively low environmental shear and above normal moisture.

GFS Shear Map (Current)

GFS Moisture Map (Current)

The favorable environmental conditions should persist as the wave moves towards the west over the next few days. This will increase the chances of tropical cyclone development by late in the week. By Saturday, the system will begin more of a west-northwest motion as it approaches the Lesser Antilles. Beyond this upcoming weekend is when the numerical guidance begins differing, and shows slightly different synoptic patterns. It is too early to determine the synoptic pattern, which will influence the track of this wave (or tropical cyclone at this point if it develops); and, the numerical guidance is not of much help with the synoptic pattern this far out.

GFS 500mb Map (Wednesday; July 12th)

Canadian 500mb Map (Wednesday; July 12th)

European 500mb Map (Tuesday; July 11th)

It appears a trough will dig into the central/eastern United States around this time-frame (mid-next week–not this upcoming week). Depending on the exact placement and strength of this trough, the strength of the potential tropical cyclone, and the placement of the Bermuda high will play large factors in the movement of this system. Again, the numerical guidance is handling these features differently, which is why they’re forecasting different tracks. It is too early to say if the United States is in the all clear or if there will be impacts. Firsthand Weather will continue to keep an eye on this wave, so keep checking back frequently for updates as confidence begins to increase.