Hurricane Isaias (pronounced ees-ah-EE-ahs) plowed through the Bahama Island chain Friday and Saturday, making landfall over Andros Island in the northwest Bahamas late Saturday morning. Isaias is predicted to bring heavy rains and strong winds to the entire U.S. East Coast Saturday through Tuesday.
At 11 a.m. Saturday, August 1, Isaias was pounding the northwest Bahamas as a category 1 hurricane with 80 mph winds and a central pressure of 987 mb. An observing site at Blue Lagoon on New Providence Island recorded sustained winds of 61 mph, gusting to 63 mph, at 8:30 a.m. EDT Saturday. The capital of Nassau, on New Providence Island, reported sustained winds of 36 mph, gusting to 49 mph, at 11 a.m. EDT Saturday. A personal weather station on Crooked Island received 4.24” of rain on Friday.
Bahamas radar showed that Isaias has struggled to build an eyewall from Friday afternoon through Saturday afternoon, and has typically been able to maintain only about 50% of a complete eyewall, located along the north side of its center (see the excellent radar loop from Brian McNoldy). Unfortunately, Isaias is likely to pass very close on Saturday afternoon to one of the Bahama Islands hardest-hit by last year’s Hurricane Dorian, Grand Bahama Island.
Considerable damage in the Dominican Republic and Puerto Rico
In the Dominican Republic, floods from Isaias’s heavy rains killed two people, damaged or destroyed 167 homes, and caused the evacuation of 5,595 people, according to Dominican Today. Flooding knocked out 73 aqueducts, affecting the water supply for 1.4 million people. The peak 24-hour rainfall amount in the Dominican Republic was 11.00″ (279.4 mm) at Sabana De La Mar, on the north coast.
Isaias brought torrential rains and flooding to Puerto Rico, with preliminary flood damage to the municipality of Mayagüez, on the west coast of the island, estimated at $14 million, according to El Nuevo Dia. The storm knocked out power to more than 448,000 customers at its height on Thursday.
Entire U.S. East Coast to get impacts from Isaias
Tropical storm and hurricane warnings have been hoisted for most of the east coast of Florida, and it is likely that nearly the entire U.S. East Coast will be under a watch or warning from Isaias at some time between Saturday and Tuesday. The region at highest risk is eastern North Carolina, which on Monday may lie on the strong (right-hand) side of a potential landfall by Isaias.
Isaias’s first spiral band to affect Florida moved over Miami on Saturday morning, and rainfall amounts of 2 – 4 inches are expected along the state’s east coast through Monday. In the Lake Okeechobee watershed, rains of about two inches are expected. This should not be a concern for the lake’s water level, which stood at 13.21′ on July 31 – about 0.5 feet below average for the date. The Army Corps of Engineers tries to maintain the water levels in the lake below a maximum of 15.5′ in order to relieve pressure on the aging Herbert Hoover Dike that surrounds the lake. Two inches of rain can raise the water levels in the lake a little less than a foot, so Isaias’s rains should keep the lake well below the 15.5′ level. The increased water levels in the lake resulting from Isaias’s rains will not lead to water releases, which have created toxic algae blooms along both the east and west coasts of Florida in the past. I discussed the issues bedeviling the dike in a 2017 post after Hurricane Irma’s rains of 8 – 12″ raised the lake level by 3.5′.
Forecast for Isaias
Satellite images on Saturday afternoon showed that Isaias had a large area of intense thunderstorms along the east side of the center of circulation. Isaias was in a region dominated by southwesterly upper-level winds associated with a large-scale trough of low pressure. These winds were creating unfavorable conditions for intensification, with high wind shear of 20 – 25 knots. In addition, this shear was driving dry air from the west side of the hurricane into its center, keeping heavy thunderstorms limited on its west side. Sea surface temperatures (SSTs) were a warm 29 – 29.5 degrees Celsius (84 – 85°F), and Isaias was embedded in a moderately dry atmosphere with a mid-level relative humidity of 50 – 55%. Overall, these conditions favor only slow changes to Isaias’s strength through Monday. Most of the intensity models favor slow weakening, as does the official NHC forecast.
The models are very unified in bringing Isaias to a point very close to the coast in central Florida on Sunday afternoon, when Isaias is expected to turn more to the north and north-northeast as a result of the steering influence of the trough of low pressure to its west.
On Monday and Tuesday, Isaias may experience a reduction in shear, to 10 – 20 knots, as shown in the 12Z Saturday run of the SHIPS model. With SSTs of 29 – 29.5 degrees Celsius (84 – 85°F) – unusually warm for late July – extending northwards all along the coasts of South and North Carolina, Isaias could be strengthening because of the reduced shear and warm water as it approaches a possible landfall in the Carolinas on Monday afternoon or evening.
Once Isaias moves beyond the warm Gulf Stream waters to the north of North Carolina, steady weakening is likely, with most of the intensity models and the official NHC forecast predicting it by then will be a strong tropical storm with 55 – 70 mph winds during its closest approach to New England on Tuesday night through Wednesday morning. Rainfall will be increasing on the west side of Isaias over time, and totals of 4″ – 6″ will be possible along the urban corridor from Washington to New York.
Short-lived Tropical Depression Ten forms off the coast of Africa
Tropical wave 93L developed into Tropical Depression Ten between the Cabo Verde Islands and the coast of Africa on Friday afternoon. The depression is unlikely to survive into Sunday, though, since on Saturday morning it moved over cool waters with SSTs of 25 degrees Celsius (77°F).
TD 10 had only a limited amount of heavy thunderstorm activity Saturday afternoon, as seen on satellite images. At 11 a.m. EDT Saturday, with top winds of 30 mph, TD 10 was headed northwestwards at 14 mph. This track will take it into a stable air mass and over even cooler waters, and TD 10 is expected to dissipate by Sunday morning.
Next system to watch for development
A westward-moving tropical wave located about 600 miles east of the Leeward Islands on Saturday morning was producing a bit of shower activity. Some slow development of this system is possible as it turns northwestward and passes well north of the Leeward Islands by Monday.
In an 8 a.m. EDT Saturday Tropical Weather Outlook, NHC gave the system two-day and five-day odds of formation of 10% and 60%, respectively. Although the system has some model support for development, it does not appear to be a threat to any land areas.
The next name on the Atlantic list of storms is Josephine. The current record for earliest 10th Atlantic named storm formation is August 22, 2005, when Jose formed.
7/31 Original Post
Hurricane Isaias (pronounced ees-ah-EE-ahs) made landfall as a tropical storm with 60 mph winds on Thursday afternoon on the southeast coast of the Dominican Republic, bringing damaging flooding, as well as drought relief, to Puerto Rico and the Dominican Republic. Isaias is predicted to bring heavy rains and strong winds to the entire Bahama Island chain Friday and Saturday, and to the entire U.S. East Coast Saturday through Tuesday.
At 11 a.m. Friday, July 31, Isaias was pounding the southeastern Bahamas as a category 1 hurricane with 75 mph winds. A private weather observing site at Long Bay Beach in Providenciales reported a sustained wind of 55 mph (86 km/h) and a gust to 59 mph (95 km/h) early Friday morning.
Damaging flooding, drought relief for Puerto Rico and Dominican Republic
Isaias brought torrential rains and flooding to Puerto Rico, with more than half of Puerto Rico receiving between five and 12 inches of rain (Figure 1). At the peak of the storm on Thursday, the National Weather Service in San Juan, Puerto Rico, listed seven rivers on the island that were above flood stage, and 15 others near flood stage.
Preliminary flood damage to the municipality of Mayagüez, on the west coast of the island, was estimated at $14 million, said the manager of the Municipal Emergency Management Office, Israel Martínez Cuevas, in an interview with El Nuevo Dia. The storm knocked out power to more than 448,000 customers in Puerto Rico on Thursday, Fernando Padilla, an official with the Puerto Rico Electric Power Authority, told Primera Hora. Main-trunk transmission lines that carry electricity from the south to the north of the island were down, as were local transmission lines.
In the Dominican Republic, floods from Isaias’s heavy rains knocked out power, flooded roads, and caused at least one death, according to Dominican Today. A Weather Underground personal weather station on the north shore of the Dominican Republic at Playa Bonita Beach reported 8 inches of rain on Thursday, July 30. At Hato Mayor del Rey in the east-central Dominican Republic, six feet of flooding occurred in some buildings, according to this tweet.
On the positive side, Isaias’s rains will help alleviate moderate to severe drought conditions that were affecting both Puerto Rico and the Dominican Republic, as explained in our YCC post on Wednesday.
Entire U.S. East Coast at risk from Isaias
Tropical storm and hurricane warnings have been hoisted for the entire Bahama Islands chain and portions of the Florida coast, and it appears likely that nearly the entire U.S. East Coast will be under a watch or warning from Isaias at some time between Friday and Tuesday. The region at highest risk is eastern North Carolina, which on Monday may lie on the strong (right-hand) side of a potential landfall by Isaias.
Satellite images on Friday afternoon showed that Isaias had a large area of intense thunderstorms, which were building over the center of circulation after it had been partially exposed on Friday morning by an intrusion of dry air. Isaias had begun bumping into a region dominated by southwesterly upper-level winds associated with a large-scale trough of low pressure. These winds were creating less favorable conditions for intensification, with moderate to high wind shear of 15 – 25 knots. Sea surface temperatures (SSTs) remained a warm 29 – 29.5 degrees Celsius (84 – 85°F), and Isaias was embedded in a moderately dry atmosphere with a mid-level relative humidity of 50 – 55%. Bahamas radar showed that Isaias had built about 50% of a complete eyewall.
Overall, these conditions favor only slow changes to Isaias’s strength through Saturday as the storm tracks to the northwest through the Bahamas and close to the east coast of Florida. Most of the intensity models favor slow weakening, but the official NHC forecast favors slow strengthening. A weaker Isaias will tend to track more to the west, potentially allowing a landfall in Florida, while a stronger storm will tend to feel the influence of the upper-level southwesterly winds on its west side, resulting in a more easterly track, keeping Isaias more to the east and preventing a Florida landfall. Unfortunately, Isaias is likely to pass close to the Bahama Islands hardest-hit by last year’s Hurricane Dorian, Grand Bahama Island and Great Abaco Island (Figure 4).
On Sunday and Monday, when Isaias is expected to turn more to the north and north-northeast as a result of the steering influence of the trough of low pressure to its west, the storm may experience a reduction in shear, to 10 – 20 knots (the technical reasons for this were well-explained in a Thursday night video discussion by Levi Cowan). SSTs of 29 – 29.5 degrees Celsius (84 – 85°F) – unusually warm for late July – extend northwards all along the coasts of South and North Carolina, so Isaias could be strengthening because of reduced shear and warm water as it approaches a possible landfall in the Carolinas on Monday.
Once Isaias moves beyond the warm Gulf Stream waters to the north of North Carolina, steady weakening is likely, with most of the intensity models and the official NHC forecast predicting it by then will be a strong tropical storm with 60 – 70 mph winds during its closest approach to New England on Tuesday.
Bahamas still recovering from 2019’s Hurricane Dorian
Isaias will be an unwelcome menace in the Bahama Islands, which are still recovering from the catastrophic impact of category 5 Hurricane Dorian of last year. After hitting St. Thomas in the U.S. Virgin Islands as a category 1 hurricane last August 28 and causing $150 million in damage to the Caribbean islands, Hurricane Dorian rapidly intensified into a category 5 mega-hurricane that powered ashore on Great Abaco Island in the Bahamas on September 1, 2019, with sustained winds of 185 mph. Dorian tied for third-strongest landfalling tropical cyclone in world history.
At landfall, Dorian was moving at just 5 mph, and portions of Dorian’s eyewall lashed Great Abaco and Grand Bahama islands with category 5 winds for a total of 22 hours before the great hurricane finally weakened to category 4 strength. Dorian’s extreme winds, storm surge of 20 – 25 feet, and rains of up to 3 feet (0.9 m) of rain combined to bring the Bahamas their most devastating natural disaster in history.
A November 15 report from the Inter-American Development Bank put damage in the Bahamas from Dorian at $3.4 billion – over 25% of their $12 billion GDP, and their most expensive disaster in history. Insurance broker Aon put Dorian’s damages at over $8 billion. Dorian killed 74 and left 282 people missing in the Bahamas, according to reliefweb.com. The authors of that report said that as of May 20, water, electricity, sanitation, and shelter continued to be challenges on Abaco Island. Medical care is also a problem, particularly with the COVID-19 pandemic occurring. The Bahamas began seeing a sharp increase in COVID-19 cases beginning in July, and had 508 total cases and 14 deaths as of July 30, according to worldometers.info.
Invest 93L off the coast of Africa unlikely to develop
A tropical wave with a well-defined surface circulation between the Cabo Verde Islands and the coast of Africa, designated Invest 93L, was suffering from high wind shear on Friday, and had only a limited amount of heavy thunderstorm activity, as shown on satellite images. The system was headed northwards into a stable air mass and over cooler waters, and it is likely to dissipate early next week. In an 8 a.m. EDT Friday Tropical Weather Outlook, NHC gave 93L two-day and five-day odds of formation of 20%.
A westward-moving tropical wave located about 1,000 miles east of the Lesser Antilles on Friday morning was producing a limited amount of shower activity. Some slow development of this system is possible as it turns northwestward over the western Atlantic by early next week. In an 8 a.m. EDT Friday Tropical Weather Outlook, NHC gave the system two-day and five-day odds of formation of 0% and 20%, respectively. Although the system has some model support for development, there does not appear to be a threat to any land areas.
The next name on the Atlantic list of storms is Josephine. The current record for earliest 10th Atlantic named storm formation is August 22, when Jose formed in 2005.
Thanks go to Bob Henson for assisting with this post.
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CDO begun to the east of center due to shear, eye becoming evident. Banding beginning to become evident to the west. Can the CDO fill in the western side? Dry air vs Gulf Stream. https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/taw/13/1800×1080.jpg
A CDO filling in cyclonically is highly unlikely through dry continental air. Never bet against the NHC or Levi. The western side of Isaias will be under the Gulf Stream tonight during D-max. But the dry air will be knocking too. What a storm and questions yet to be answered.
Positive tilt Isaias. Positive tilt anti-cyclone. I storm on the Gulf Stream in 2020. Tonight will tell. https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/taw/08/1800×1080.jpg http://tropic.ssec.wisc.edu/real-time/atlantic/winds/wg8shr.GIF
Still a lot of rain over Grand Bahama…
Well … Finally getting some more rain … Somehow I didn’t think we were done with Isaias …. 😁
Guess I’ll be posting this here since I’m still banned on C6
Following a July that set a record for activity, I found my previous forecast update to be lower than my current expectations. Thus, I have raised my numbers for the season overall based on continued environmental trends. As a reminder, I am not a meteorologist, and the information disseminated here should not be taken over the data presented by NOAA.
August Forecast for the AHS
Hyperactive – 70%
Active – 25%
Average – 5%
Below Average – near 0%
Named Storms – 21 to 24 (14.75) [11.691]
Hurricanes – 9 to 12 (7.541) [6.294]
Major Hurricanes – 4 to 7 (3.458) [2.588]
ACE – 180 to 210 (132.393) [102.920]
ENSO
As expected, the subsurface cold pool in the equatorial Pacific has continued to progress east. A lull in anomalously strong trade winds forced by the strengthening of the ASW and the +IOD it stimulated is now over, and anomalous easterlies are once again prevalent in the nino regions. This has allowed for the propagation of a new upwelling kelvin wave, which should keep us in -ENSO (if not La Nina) territory through ASO and likely into 2021.
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/weeklyenso_clim_81-10/wkteq_xz.gif
http://www.atmos.albany.edu/student/ventrice/real_time/timeLon/u.anom.30.5S-5N.gif
TAO Buoy Array https://cdn.discordapp.com/attachments/733552978572869632/738860917902540890/dep_lon_EQ_20200728_t_mean_20200728_t_anom_500_0_500_0_hf_2020073113.png
As implied earlier, the expected transition to a negative IOD has not taken place. This can largely be attributed to the scale of the rising motion associated with the African Standing wave. The consequences of the state of the IOD at this point in time are rather limited, and the ASW would be powerful regardless. The rare juxtaposition of atmospheric -ENSO and +IOD also seems to be suppressing tropical activity in the Western and Eastern Pacific.
https://cdn.discordapp.com/attachments/733552978572869632/738863375865610361/compday.png
Interestingly enough, velocity potential anomalies closely resemble that of a stronger Nina event (albeit shifted a bit west). This is again likely a result of a dipole forced by the powerful ASW
https://cdn.discordapp.com/attachments/662369814085632020/716690019372236800/Ckwpjkkog4.png
The warmest SST anomalies in the entirety of the Pacific Ocean are located at about 40N/160W, which is usually a good indicator of a negative PDO. The aforementioned SST’s are up to six degrees celsius above average, and are generally surrounded by colder anomalies. A negative PDO encourages the development of a stronger La Nina event as the associated subtropical ridge induces northeasterly flow over the NPMM region.
https://cyclonicwx.com/data/sst/crw_ssta_global.png
The latest CPC/IRI forecast shows probabilities for a continuing neutral slowly decreasing as time goes on, with the probabilities for La Nina going up.
https://iri.columbia.edu/wp-content/uploads/2020/07/figure1.png
This is in conjunction with recent CFSv2 forecasts that continue to predict a La Nina event occurring by the end of the year.
https://www.cpc.ncep.noaa.gov/products/CFSv2/imagesInd3/nino34Mon.gif
Generally, a -ENSO event portends to lower than average shear in the Atlantic and higher stability in the Pacific.
AMO/WAM
The dominant SSTA pattern in the North Atlantic doesn’t exactly resemble a canonical +AMO, but features the trademark warm MDR. The subtropics are notably warm, though not warm enough compared to the MDR to force any considerable subsidence.
https://cyclonicwx.com/data/sst/crw_ssta_natl.png
This graphic from @webberweather is rather worrying, showing that a vast region of the MDR is at record warm levels. This increases instability, and overall provides a more favorable environment for TC’s.
https://cdn.discordapp.com/attachments/733552978572869632/738867623906902106/EduY_CQXgAEQG5S.png
To put this into perspective, here are some charts from @cyclonicwx and myself comparing 2020 to some other years that have notoriety for their MDR warmth – 2005, 2010, and 2017.
https://cdn.discordapp.com/attachments/733552978572869632/738871726254981221/oisstdif.png
https://cyclonicwx.com/data/sst/2010compare.png
https://cyclonicwx.com/data/sst/2005compare.png
Continued WWB’s over the Tropical Atlantic should allow for the maintenance or intensification of this warmth through the next few months.
https://cyclonicwx.com/data/models/gfs/gfs_15N_hov_uanom_2020073118.png
The West African Monsoon has been (and will continue to be) anomalously strong. Not only is there strong rising motion over Africa, but it has also set up in a north/south dipole that matches the maximum precipitation and humidity anomalies. This will continue to lead to vigorous AEW’s emerging from Africa throughout the majority of ASO.
https://cdn.discordapp.com/attachments/733552978572869632/738983196024242186/compday.png
https://cdn.discordapp.com/attachments/733552978572869632/738983533909114880/compday.png
https://cdn.discordapp.com/attachments/733552978572869632/738983969437122640/compday.png
Activity will likely pick up in the latter portion of August, as the ITCZ begins to recede from its seasonal peak latitude. The recession would imply less SAL, and strong waves tracking over warm SST’s with decent RH.
Other
Meanwhile, in the Gulf of Mexico, a large eddy appears to have been broken off. Alongside this, TCHP levels appear to be relatively high. Both of these can fuel storms by maintaining their intensity or intensifying in the Gulf or Caribbean, although they aren’t absolutely necessary.
https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/glfmexspdcur_nowcast_anim30d.gif
Overall I continue to expect a hyperactive hurricane season, given the continuation of -ENSO alongside a record warm tropical Atlantic. It should be noted, however, that it only takes one storm to make a memorable season, and everyone should be prepared beforehand regardless. This is an unofficial forecast created by a highschool student, with what amounts to a piecemeal knowledge of meteorology. Thank you for reading everyone!
Good evening !
In 1979 I was woken up In the middle of the night by fire truck lights and sirens and a man on a bullhorn telling us to evacuate Cape Canaveral because hurricane David had strengthened and changed course. I was 16 and my mom told me to quickly grab the most important 3 things from my room and get in the car. Of course I grabbed my guinea pig and we drove to a friends house in Rockledge on the mainland. I remember going outside in the eye in total awe. And I remember the back side feeling 100 times worse than the front. It was the scariest night of my life even until now. Sitting here tonight brings back lots of David memories. I know this isn’t a David but sure hoping this one stays below cat 2. A direct hit from a cat 2 is about as much as I would ever want to see. And I would prefer not to see another!
Closely watching Isaias’s evolution as he approaches Florida. The storm is expected to move near or over NJ in 3-5 days and will bring impacts to my area.
Meanwhile, the Northwest Pacific basin has two tropical storms now, after a record lull of no TS-strength storms in July.
Japan Meteorological Agency
Tropical Cyclone Advisory #17 – 9:00 AM JST August 2 2020
TROPICAL STORM SINLAKU (T2003)
———————————-
Gulf of Tonkin
At 0:00 AM UTC, Tropical Storm Sinlaku (992 hPa) located at 19.2N 106.1E has 10 minute sustained winds of 35 knots with gusts of 50 knots. The cyclone is reported as moving west at 9 knots.
Gale Force Winds
===================
600 nm from the center in southern quadrant
300 nm from the center in northern quadrant
Dvorak Intensity: T2.5-
Forecast and Intensity
========================
24 HRS: 20.2N 102.4E – Tropical Depression over land Laos
The anti-cyclone is very undernoted to strengthening potential. It’s positive tilt is feeding Isaias and venting the system. http://tropic.ssec.wisc.edu/real-time/atlantic/winds/wg8shr.GIF
Hurricane Uniting would be nice. Let me know when that lands.
Japan Meteorological Agency
Tropical Cyclone Advisory #9 – 9:00 AM JST August 2 2020
TROPICAL STORM HAGUPIT (T2004)
———————————-
220 km southeast of Ishigaki Island (Okinawa Prefecture)
At 0:00 AM UTC, Tropical Storm Hagupit (1000 hPa) located at 22.6N 125.1E has 10 minute sustained winds of 40 knots with gusts of 60 knots. The cyclone is reported as moving northwest at 11 knots.
Gale Force Winds
==================
120 nm from the center in northeastern quadrant
90 nm from the center in southwestern quadrant
Dvorak Intensity: T2.5-
Forecast and Intensity
========================
24 HRS: 25.1N 123.0E – 65 knots (CAT 3/Strong Typhoon) 70 km north of Yonaguni Island (Okinawa Prefecture)
48 HRS: 29.6N 120.2E – 55 knots (CAT 2/Severe Tropical Storm) Over land central China
72 HRS: 35.8N 121.3E – 40 knots (CAT 1/Tropical Storm) Yellow Sea
Eye evidenced and CDO still rapidly growing. Does not look good. Notice the eye is surrounded by reversed curved banding. A sign of strenghtening. The eye has an eyebrow above and below. Now is the time to prepare for a stronger storm by morning. One will note the convection is connected to the anti-cyclone directly south. https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/taw/13/1800×1080.jpg
We’re often slow to catch up to what’s actually happening. Would this blowup happen if shear hadn’t relaxed? No. Is that a problem with Isaias beginning the turn slowly feeding off the Gulf Stream? Yes. Should we expect D-Max to be a show? Likely. Will we wake up to a stronger Isaias tomorrow? Almost guaranteed.
What’s up with the low level swirl moving west?
I figured we’d need an Ignore/Block list by the end of September. Any chance we get one sooner rather than later? There’s a small number of inveterate wishcasters that are practically begging to go on my block list. I’d like that functionality ASAP, please.
Evening all. After several hours of on again off again, it seems our power has been fully re-established. After observing a rather satisfactory shredding of Isaias this afternoon, I’m a bit dismayed to see such a healthy blowup in the last couple of hours. Hopefully this will not bring too much rain to Grand Bahama ….
Yup, hope it spares Abacos as well
Good to hear that this one didn’t completely explode into a monster for once. That almost seems to be the exception nowadays. Ya’ll can use a break
Isaias is feeding off the anti-cyclone below Cuba. Double the pleasure with this anti-cyclone, wind shear venting and moisture feed. Nothing wrong with preparing for a stronger storm. If you’re in Florida, don’t be surprised if you wake up to a 100mph Isaias, with it’s eye right off shore. https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/taw/13/1800×1080.jpg
Charleston, S.C looking like ground zero for landfall. Been ground zero for Covid-19 for some time in South Carolina. Hottest county for outbreak in the State.
NHC go low and catch up as conditions warrant. I downstream look with logical reasoning. Not like hurricanes have been obeying forecasts for a long time. Could Isaias be still a tropical storm with dry air entraining by morning? Yes. Could it be a hurricane approaching category 2 strength? Yes. Always prepare for the worst. No matter how many times you’ve been fortunate.
A stronger storm, with the eye hugging the coast of eastern Florida, will likely have a unique storm surge effect too. Half onshore half off for the eye even a possibility. We are now in CDO blowup that is looking like the real deal. I storm riding the Gulf Stream. I don’t like it.
Most recent recon pass looks like it found a center at 994-ish right under that blow up. I think it’s probably too little, too late for RI, but my money is on Isaias regaining hurricane status next update.
Much more concerning is that, if this is actually the center they just flew through, it looks like Isaias has stalled right over the Gulf Stream…
The 5 PM Forecast Discussion says, “Isaias is forecast to regain hurricane status tonight”, so your prediction of what happens on the next update isn’t much of a prediction. Ain’t nobody putting any money on that.
Miami radar appears to indicate a very small eye forming
Wrapping up tightly
Is the eye going to be in the new blow up or just to the southwest of the blowup? If the true eye is in the growing CDO, then it’s more likely for real intensification and possibly explosive growth. If the eye is the low level feature southwest of the convection, then the CDO would have to cyclonic wrap into massively dry air to the west. That just won’t work. A lot yet to be determined. https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/taw/13/1800×1080.jpg
Holy bloomers, Batman!
To my eyes, the entire western half is already nicely organized and spinning, eh? Is that eastern half going to wrap/attach for enhanced convection? Seems primed. Ugh.
It looks spot on to the NHC discussion from 5pm, this is the last good window Isaias has for intensifying
Lightning activity as detected by the Blitzortung detector network over the past 120 minutes. White crosses indicate strikes in the last 20 minutes. Dark red ones are the oldest strikes.
https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/taw/13/1800×1080.jpg I storm over the Gulf Stream. Isaias finally showing up dressed for the show tonight? May not have underwent RI, but after losing it’s southern blob helper days ago, still intensified while looking like a weak tropical storm. Real blowup of a CDO tonight? We’ve seen the CDO similiar to how it looks now for the last day. Clearly taking a big drink of the Gulf Stream right now. We see the CDO take off, not only is more intensity likely, so are higher rain totals.
Isaias is such a curious storm to follow and study, huh?
First, these days I strongly hedge towards storms fighting off any adverse conditions, based on recent storms/seasons. Also, potential/ability to RI – above modeling. Second, it’s never had great structure or convection IMO. Third, that question of initial separation, then spawning a twin brother. Gaining *some* nice circulation, organization, and structure immediately after a landfall? Yeah, seems more towards that hedge I just mentioned already. Isaias’ forward speed early on could’ve killed it, didn’t. Seems like so many crazy factors. Stayin’ alive. For now…
Trough of shear continues to move west, anti-cyclone just south of Cuba has continued to strengthen, Isaias finally looking clear for takeoff. Shear is not only lowering, the dry air is losing fast now to the Gulf Stream. Anti-cyclone being directly south of Isaias seems to be venting the new blowup nicely for now. Can this blowup sustain and grow into a real CDO? Hope not. http://tropic.ssec.wisc.edu/real-time/atlantic/winds/wg8shr.GIF
13News Now meteorologist Tim Pandajis is a rare exception to bad TV storm/weather reporting. I’ve been down this road for decades and Masters has been a lone voice of science. Kudos to Mr. Pandajis!
Won’t miss Weather.Com talking head in a raincoat in the lee of a beachside motel shouting over the wind about bla..bla..bla.. Blather.com
Dunno if others are here, I guess almost all prefer to stay on Disqus platform from Cat 6. I really like this format of updates… on the existing post for Isaias. Works nicely to give comprehensive info. And being able to once again comment directly on Dr. Masters great posts… Excellent.
But without power, water, and roads? In tropical August weather? Not good. With the virus and all its complications for rescue, relief, shelters, support services. Very not good. Testing sites being closed, also… not. good. And I’m thinking of the elevations across some regions, the downstream flooding effects. Ugh. Might not have the label of a destructive hurricane when interacting or landfall in the States, but I sure hope people are prepared.
Stay vigilant, stay safe! Cuídate!
Donde Esta?
I’m in Saipan, CNMI. Other side o’ the world. But, as another commonwealth territory of the States, feel a sort of distant kinship to my fellow tropical islanders. Knowing about the specific vulnerabilities we face and such, after a major storm like Hurricane Maria or Super Typhoons Yutu/Soudelor… Where are you? Cheers.