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Attention Turns to Jose, Two More Systems Active Over the Open Atlantic

Good Afternoon! 

The tropics have begun to really ramp up yet again, with Jose still meandering north of the southern Bahamas, newly formed Tropical Depression 14, and a vigorous tropical wave that has been designated Invest 96L.

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Tropical storm Jose has been on the upswing over the past 18 hours or so, as the strong wind shear that has been blasting it ever since Irma made landfall has finally abated to some degree. The storm developed very cold convection right over the center last evening, and this likely worked to help reorganize the storms core a bit, since earlier microwave passes showed that the system had become severely tilted to the point that the mid level and low level centers were no longer aligned. At this post is being written, the hurricane hunters are currently investigating the system, and have found winds just around the threshold for a Category 1 hurricane along the southeast portion of the circulation. Typically the strongest winds are found in the northeast quadrant, so I would no be surprised if this mission found winds of around 80 mph, but I will wait for the NHC to make that official decision of reclassifying it as a hurricane. As stated, shear has begun to weaken, and Jose will be over very warm sea surface temperatures of around 29-30C for the next 36 hours, along with relatively moist mid level atmospheric conditions. This should allow the system to strengthen back to a high-end Category 1 Hurricane, or even a low-end Category 2 before shear really begins to increase to high levels in about 48-60 hours.

Current hi-res visible satellite imagery of Tropical Storm Jose over the open Atlantic with 70mph winds.

Current hi-res visible satellite imagery of Tropical Storm Jose over the open Atlantic with 70 mph winds.

The track of Jose is what remains the hot-ticket item. Over the past few days, there has been a noticeable shift westward, with some global models even showing Jose making landfall along the east coast. Once Jose is positioned between Bermuda and North Carolina on Monday, steering currents will begin to break down and the storm should begin to slow a bit while moving to the north. As the storm slows down, the consensus from the reliable models seems to show that more mid level ridging will build over and around Jose to slow it down even more once we get to the Tuesday afternoon period. By this time, a the storm will likely be encountering very strong wind shear and much cooler waters, which should force it to become a large extra-tropical system near the 40/70 ‘benchmark’ by Wednesday. While direct impacts are unlikely from this system outside of some gusty winds and possible rainfall along with coasts, strong wave action and life-threatening rip currents are likely to last well into next week as the storm slowly moves eastward over time. There will also be an enhanced threat for beach erosion, especially if the storm slows down as it nears the area. We will have a special update this weekend if conditions change, and direct impacts from Jose seem to be on the increase.

This afternoons ECMWF model showing Jose south of New England and heading towards the east

This afternoons ECMWF model showing Jose south of New England and heading towards the east

Invest 96L East of the Lesser Antilles 

A strong tropical wave with a healthy amount of spin is currently located about 1000 miles east of the Lesser Antilles, and has become much better organized over the past day and a half. This system was a par of a large eastern Atlantic monsoon trough, which split into two halves, with the right side of the trough organizing into TD14. During the day today, the system has been able to sustain moderate to heavy amounts of convection over its presumed center of circulation. Visible satellite imagery shows that this system may have a weak surface reflection, with banding beginning to show up on the southern periphery of the invest. However, we have not had a reliable scatterometer pass of this system that is able to show whether or not a system has a closed surface circulation. Regardless, the system is currently within a very favorable area of windshear which lies around the 5-10 knot range. Additionally, the system is over warm waters of 28-29C, and remains embedded within a very moist pouch that surrounds the system. The environment looks very favorable for continued development of this system over the next day or so, and I would not be surprised to see the system become a tropical depression or storm as early as Saturday evening.

Invest 96L this afternoon showing the system gradually becoming better organized

Invest 96L this afternoon showing the system gradually becoming better organized

Over the next few days 96L should continue heading west/west northwest towards the Lesser Antilles, possibly reaching the islands as soon as Tuesday. With favorable environmental conditions, it appears likely that the system will at least be a mid-grade tropical storm at that point, with some of the other model guidance showing a hurricane nearing the islands. Due to the fact that we do not even know whether or not the system has a closed circulation, it is very heard to gauge exactly how strong this will be once it nears the islands, but the Islands should very closely monitor the progress of this system over the next five days, especially the island of Antigua, which is currently housing the population of Barbuda, which was completely destroyed by Irma when it was a 185 mph hurricane. The track of this system beyond the islands will be heavily reliant on the future of Jose, so make sure to check back over the next few days when these details become clearer.

This afternoons GFS model showing 96L becoming a strong tropical storm/hurricane just before reaching the Lesser Antilles

This afternoons GFS model showing 96L becoming a strong tropical storm/hurricane just before reaching the Lesser Antilles

Tropical Depression 14-No Threat To Land

TD14 formed over the far eastern Atlantic from a strong tropical wave, and was designated by the NHC yesterday evening. The system seems to be experiencing some moderate amounts of mid level shear this afternoon, which has displaced the heaviest convection from the low level center. Despite this, the system will be over warm waters and within a moist environment over the next 72 hours, and is expected to become a tropical storm over the next few days as it gradually heads WNW. TD 14 is thousands of miles away from land, and most models show the storm eventually dissipating as it encounters very strong shear and dry air from an upper level trough over the central Atlantic. Depending on what 96L does over the next 48 hours, the next two names on the list of Lee and Maria.

We will have a full update on Monday!

Afternoon visible shot of Tropical Depression 14 over the far Eastern Atlantic

Afternoon visible shot of Tropical Depression 14 over the far Eastern Atlantic

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Have a great weekend!

Steve Copertino

Cooler risks, Harvey concerns over the next week

A wonderful Tuesday morning to you, and thank you for joining us for our daily morning roundup. If you haven’t checked your email box for the latest details, we will (as always) lay them out in an understandable post-based format here. Today we’re jumping straight into discussion regarding the cooler risks in the weather pattern over the Central United States as well heightened tropical risks across the Western Gulf of Mexico late week and into the weekend.

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Dual Rain Threats This Week, Tropical Storm Gert Intensifying Off the East Coast

Good Evening! 

Today started off decently clear and warm over much of the area, but as the day progressed onward, the elongated area of high pressure just to our south began to move offshore. As it did so, this allowed low level moisture and cloudiness to begin to filter over the region, but still allowed conditions to remain slightly below-average, with highs locked in the upper 70’s to lower 80’s. As of this evening, cloudiness has begun to increase in earnest across the area in response to an impulse of mid level energy working its way north and east along mid level trough. In addition to cloudy skies, this impulse of energy has also sparked some showers over the northern portions of the Mid-Atlantic, with sections of Maryland, Delaware, Pennsylvania, and southern New Jersey all reporting light to moderate showers moving across that area this evening. This area of showers should continue to head east-northeast over the next few hours, but may have trouble making too much northern progress as there is some residual mid level dry air over portions of northern NJ and Long Island. This mid level dry air has also been noted on this evenings radar, as numerous areas of virga (rain not able to reach the ground due to dry conditions) popped up and quickly dissipated soon after.  Overall, conditions should remain cloudy with a chance of a light shower the further south you go, but with increasing moisture, light southerly winds, and increasing clouds at all levels-radiational cooling will be very hard to come except for locations in northern Pennsylvania as well as central New York. This will keep low temperatures in the mild range of the upper 60’s to lower 70’s, with temperatures around 5 degrees cooler to the north and west.

This evenings latest high resolution GEOS 16 visible satellite imagery, regional radar mosaic, surface observations, and WPC frontal locations.

This evenings latest high resolution GEOS 16 visible satellite imagery, regional radar mosaic, surface observations, and WPC frontal locations.

Tuesday Through Friday 

Tuesday morning will likely start off with numerous clouds and possible showers over the region, and another shortwave trough begins to move just to the southwest of the area, bringing another new batch of mid level instability and moisture. At this time, it appears that the best chance for steady rain will be tomorrow morning, likely over the southern portions of the New York Metro area, with locally heavy areas of rainfall possible. As the day progresses, the steadiest rain should begin to head east and off the Mid Atlantic coast. This will likely give way to improving conditions by the mid afternoon hours, with some clearing possible the further away from the coast that you area. With the mid level still feeding moisture in from the south and east, any clearing will likely allow for some instability to build up. Though we will have some instability and weak wind shear to work with tomorrow over the interior, the models indicate an area of sinking air associated with a dissipating mid level system to our north. This should greatly reduce the potential for thunderstorm coverage, but in general isolated shower and thunderstorm development is likely across portions of New York and Pennsylvania tomorrow afternoon and into the evening hours. With the lack of severe parameters coming together, the overall threat for severe weather should be quite low tomorrow, but some stronger storms could produce gusty winds, very heavy rainfall, and even small hail.

As we get closer to New York City, cloud cover and much more stable/sinking air over the region should generally limit and thunderstorm development through the evening hours, and any storms that track close to the area should be on the weakening trend and will likely die-off. With winds coming off of the Atlantic, tomorrow evening will likely be another mild and somewhat-muggy one as lows will likely stay in the low 70’s to upper 60’s across much of the area.

Wednesday should be a much more pleasant day across the Northeast, as dry air behind the mid level disturbance begins to overspread the area, knocking out much of the cloud cover during the early morning hours of the day. Mid to upper level ridging will allow for temperatures on Wednesday afternoon to get quite warm, with highs likely reaching up into the upper 80’s and into the lower 90’s across the region. Few clouds are expected through the evening hours, as a backdoor coldfront pushes from north to south across our area, working to lower dewpoints region-wide.

Thursday looks to be relatively nice for the majority of the day, as the backdoor coldfront halts its progress around the Mid Atlantic region, keep the area warm, but less humid during the day. With dry northwesterly flow established, conditions should be mostly clear across the area. This looks to change later in the evening, as a large mid level system over the Great Lakes looks to approach the Northeast after sunset and into Friday. This system will be accompanied by a strong cold front, which could be responsible for shower and thunderstorm development late Thursday and into Friday, but at this time, it does not appear that this system will carry much of a severe weather threat as well as a flooding threat. This will likely have to be reassessed later in the week, so check back for updates!

This afternoons NAM model showing the progression of Tropical Storm Gert off the east coast, as well as a mid level system over the central part of the county, which may work to bring showers and thunderstorms over our area later this week,

This afternoons NAM model showing the progression of Tropical Storm Gert off the east coast, as well as a mid level system over the central part of the county, which may work to bring showers and thunderstorms over our area later this week

Tropical Storm Gert Nearing Hurricane Intensity 

As of 5pm this evening, Tropical Storm Gert was located roughly 450 miles to the west-southwest of Bermuda, and moving north at around 8 miles per hour. Gert has taken advantage of a relatively favorable environment today characterized by low vertical wind shear, very warm sea surface temperatures, moist air, and slow storm motion. This allowed the storm to develop intense thunderstorms near the core of the system, which in turn began a period of intensification to just below hurricane status-at 70 mph. Recent visible satellite images from the GOES-16 satellite showed that the cloud tops of Gert were warming a little, maybe indicating a brief halt in the intensification process, but with the storm located over very warm water and under a favorable environment, it appears quite likely that Gert will become a hurricane within the next 12-18 hours.

Gert will continue to track to the north as it rounds the western edge of the Bermuda high tomorrow, likely continuing to strengthen as it does so. Gert will likely begin to accelerate and take on more of an easterly component later tomorrow, as a shortwave trough moves over the Northeast. As the storm begins to interact with the shortwave trough over the northern Atlantic ocean, it will likely begin its extra-tropical transition by late Wednesday. Thereafter, the storm is likely to remain a powerful extra-tropical system, which may eventually threaten portions of Europe further down the line. Impacts for the east coast will be limited to increased wave swells and a high risk of rip currents. The main risk from Gert will be help by any maritime craft venturing off the east coast this week.  Elsewhere in the Atlantic, there is an area of disturbed weather located in the far eastern Atlantic which may try to gradually develop into a tropical cyclone over the next few days as it heads generally WNW at 15mph.

GOES-16 visible satellite imagery of Tropical Storm Gert off of the southeastern coast of the US this evening (Courtesy of simuawips.com)

GOES-16 visible satellite imagery of Tropical Storm Gert off of the southeastern coast of the US this evening (Courtesy of simuawips.com)

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Have a great evening!

Steve Copertino

Public Analysis: Unsettled Conditions Continue, Keeping An Eye on Tropical Storm Cindy

Good Evening! 

As discussed back on Monday, some residual moisture and weak instability worked its way into the area during the morning and afternoon hours, and when coupled with some forcing just to our northeast, we saw scattered showers and thunderstorms develop across much of the region. These showers and thunderstorms had some decent dynamics to work with, with wind shear being high, lapse rates being quite steep, and the upper level jet streak being located in a favorable position for divergence aloft. Since these conditions came together just at the right time, we actually saw some strong to locally severe thunderstorms develop over New Jersey, Pennsylvania, and portions of Connecticut. A segment developed in Pennsylvania and went on to track east, leaving numerous wind damage reports in its wake. Further north, isolated cells developed over southern New York and went on to track into Connecticut, which brought a few small hail reports and isolated wind damage reports.

As of right now, these storms have begun to weaken and are moving off the coast as the best dynamics and instability begin to fade away. Despite the storms and occasional cloudiness, temperatures were able to rise into the low to middle 80’s across much of the area. The cold front which acted as the lifting mechanism for today’s storms will begin to move through the region and bring a drier airmass in its wake later this evening. Clouds should begin to diminish by sunset, which should allow temperatures to fall back down into the 60’s tonight, with lows in the 50’s possible farther north and east of the city.

This evenings latest high resolution visible satellite imagery, regional radar mosaic, and surface station plots, showing the bulk of the shower and thunderstorm activity pushing to the east.

This evenings latest high resolution visible satellite imagery, regional radar mosaic, and surface station plots, showing the bulk of the shower and thunderstorm activity pushing to the east.

Thursday into Friday 

Thursday should start off as a rather beautiful day with low humidity, clear skies, and light winds from the west. Weak high pressure at the surface and aloft will allow the area to stay mostly-sunny during the day tomorrow, with just some upper level cirrus clouds likely approaching the area. Temperatures aloft will be rather mild thanks to the ridging overhead, so expect to see highs in the low to middle 80’s once again tomorrow, except this time it will feel more pleasant due to the lower dew points. Later in the evening tomorrow, low level moisture advection will begin to overspread the area due to a weak warm front aloft. This moisture will be quite rich in nature, as the majority of it is being fed from the deep south and portions of the Gulf of Mexico thanks to Tropical Storm Cindy. Some elevated showers and thunderstorms may try to develop late tomorrow evening as the moisture feed begins to overspread the region, but at the very least it seems likely that clouds will increase in earnest tomorrow night. The increased cloudy skies and rich moisture feed will lead to low temperatures not really being able to fall all that much, with temperatures in the low 70’s likely across most of the area.

This afternoons Rapid Precision model, showing the potential for heavy rains associated with the remnants of Tropical Storm Cindy to affect the region on Friday and into Saturday (Credit: WSI)

This afternoons Rapid Precision model, showing the potential for heavy rains associated with the remnants of Tropical Storm Cindy to affect the region on Friday and into Saturday (Credit: WSI)

The forecast on Friday becomes quite complex as a strong northern stream disturbance begins to interact with the remnants of Tropical Storm Cindy, which will likely be situated over the Ozarks by Friday morning. The aforementioned warm front that we talked about for Thursday evening should be through the area by Friday afternoon, leaving most of the area with partly cloudy skies and warm temperatures once again.

Highs will likely be able to climb into the middle 80’s with ease, but the increasing moisture from the south will also raise the dewpoints over the area, possibly making for a very muggy afternoon. With sunshine likely during the afternoon hours and an abundance of moisture also in place, instability will build over the area, and will be accompanied by some modest wind shear over the area. The pieces will be in place for heavy showers and thunderstorms to go up over the area during the afternoon hours, but the item in question will be whether or not we have a direct trigger to set off any storms. At this time, it appears likely that an adequate amount of mid level energy will be in place to set off the development of some isolated showers and thunderstorms capable of producing gusty winds and very heavy rainfall rates, possibly causing some localized flooding.

As we head into the late afternoon and evening, the threat for more showers and thunderstorms will increase markedly as the direct remnant moisture from Tropical Storm Cindy begin to crash into a cold front located to our west. Again, the main question that will be determining whether or not we see widespread heavy rainfall comes down the need for a “trigger” mechanism. One possible outcome is that Cindy deteriorates after making landfall to the point that the systems energy is dissipated, and all that is left is just some moisture. This outcome would lead to showers and thunderstorms being more scattered during the later portion of Friday, but still have the potential for heavy, tropical downpours.

The second option would be that Cindy does maintain itself as a coherent and trackable system in at least the mid levels of the atmosphere. This would allow the residual lift from the decaying tropical storm to spark numerous showers and thunderstorms during the afternoon hours of Friday, and would carry a much greater threat of torrential downpours and localized flooding concerns. At this time, it is looking likely that what will happen will be a healthy blend of both scenarios, with Cindy retaining some mid level energy that will set off heavy showers and storms just to the west of the NYC area, which will have the potential to track eastward and put down some impressive rainfall totals in a short period of time. This solution is baked up by this afternoons European model and the American model. Since Cindy has not yet made landfall, this solution may still change, so be sure to stay up to date and check back again over the coming days! Also, please keep an eye on the latest NWS products in the event that Flood Watches are issued down the line.

Image showing very impressive amounts of water vapor being advected north over our area, which will greatly increase the threat of heavy showers and thunderstorms.

Image showing very impressive amounts of water vapor being advected north over our area, which will greatly increase the threat of heavy showers and thunderstorms.

Saturday and Beyond

Heavy showers and storms may continue into the early morning hours of Saturday and possibly even the afternoon as the cold front pushes through the area, dragging the rest of the deep tropical moisture with it. There are still some model difference on fast the cold front with tropical moisture moves offshore Saturday afternoon. If the front is slower, a more showers and thunderstorms could linger into Saturday afternoon. But latest model trends have been faster, so we are still leaning to more clearing skies by Saturday afternoon. More sunshine will help temperatures rise into middle 80s on Saturday afternoon.

The cold front and its associated moisture should then begin to shift well offshore, leaving an area of weak high pressure in its wake. Sunday should be quite pleasant, with clearing skies and highs in the lower 80’s, also accompanied by a much more comfortable airmass.

An active northern stream will keep conditions relatively unsettled for the foreseeable future, with a chance at a cool-down later in the week as well.

This afternoons European ensemble mean showing a shot at some cooler weather into the middle portion of next week (Courtesy of WeatherBell)

This afternoons European ensemble mean showing a shot at some cooler weather into the middle portion of next week (Courtesy of WeatherBell)

For more information and posts like this one, make sure you sign up for Premium Forecasts — where multiple detailed articles, videos, and interactives are posted each day. Also, come interact with our staff and many other weather enthusiasts at 33andrain.com!

Have a great evening!

Steve Copertino