[sdanseo]

TD TEN has gone from a blip, to 50% chance of cyclone, to a TD in less than 24hrs.

2 systems now and one more potentially in the Atlantic basin.

All Atlantic systems this year, though we are at I in the alphabet already, have been weak enough so far. Isaias a bit different, it exceeded the initial NHC speed predictions in very short order and even they are saying current wind speed estimate is probably conservative, but future forecast now seems downgraded a little again in the latest discussion (there were 80kt values previously)

Hurricane Isaias Discussion Number 15
NWS National Hurricane Center Miami FL AL092020
500 PM EDT Fri Jul 31 2020

Deep convection, with occasional overshooting cloud tops of -85C to
-90C just north of the center, has continued to develop during the
normal diurnal convective minimum period, which is quite impressive.
The most recent Air Force Reserve recon flight-level wind data,
along with ASCAT surface wind data, indicate that the inner-core and
outer wind field have both contracted in size. Furthermore, radar
data from the Bahamas and an 1810Z AMSR-2 microwave pass also
indicate that a small 10-nmi-wide mid-level eye is forming. The last
recon central pressure was 991 mb and the 700 mb height had
decreased by 30 meters since the earlier maximum height around
1230Z. These data indicate that Isaias is getting better organized.
The initial intensity remains 65 kt based on an earlier 700-mb
flight-level wind speed of 72 kt, which reduces to a 65-kt surface
wind speed using a 90-percent adjustment factor.

FORECAST POSITIONS AND MAX WINDS

INIT 31/2100Z 22.6N 75.7W 65 KT 75 MPH
12H 01/0600Z 23.9N 77.2W 70 KT 80 MPH
24H 01/1800Z 25.4N 78.8W 75 KT 85 MPH
36H 02/0600Z 26.8N 79.9W 70 KT 80 MPH
48H 02/1800Z 28.3N 80.4W 65 KT 75 MPH
60H 03/0600Z 30.0N 80.4W 60 KT 70 MPH
72H 03/1800Z 32.5N 79.4W 60 KT 70 MPH
96H 04/1800Z 39.0N 74.5W 55 KT 65 MPH
120H 05/1800Z 45.4N 65.9W 50 KT 60 MPH...POST-TROP/EXTRATRO

[Gaoth Laidir]

The arse has fallen out of Isaias a bit this evening as it's back down to Tropical Storm 60 kts. Dry air, windshear and the Bahamas islands have interfered with its circulation, which never properly formed in the first place. It is expected to strengthen slightly back to 65 knots over the next day or so as it passes close to the east Florida coast, though with any real winds well out to its east there should be no real problems for Florida. Rain bands have been coming into the Miami - Pompano Beach area this evening but they're fairly broken up and relatively light. The partial eyewall is visible on Miami radar but it's nothing more than a curved band.

Tropical Depression Ten passed just north of Cabo Verde and fizzled out having maxed out briefly at 35 knots.

[Gaoth Laidir]

Not surprisingly, the latest NHC discussion has found Isaias to be weaker and suffering from dry air and 25 kt of wind shear. The intensity has been lowered to 55 knots (in a small area to the east) and no further strengthening is forecast as it brushes up along the east coast of Florida and into the Carolinas.

Winds along the Florida coast are in the 15-25-kt range.

[Oneiric 3]

Coming up against a large bank of drier air now which won't help any potential further development:




And looking at a live cam of Miami beach, nothing seems out of the ordinary wind wise. A mere flutter:

[Oneiric 3]

North Carolina live cam. Sky there currently looks similar to what we have had 95% of the time here in the west of Ireland this summer, but this is east coast America, and such a sky will always proceed something just a bit bigger than a few spits of patchy light rain and drizzle.

https://www.youtube.com/watch?v=iZh6lBhALwU

[Gaoth Laidir]

Isaias made it back to hurricane strength just before landfall in southern North Carolina. Some isolated hurricane-force winds were recorded along the extreme coast but the majority of stations were well below it.

Hurricane Isaias Tropical Cyclone Update
NWS National Hurricane Center Miami FL
AL092020 1115 PM EDT Mon Aug 3 2020

Doppler radar imagery and surface observations indicate that eye of Hurricane Isaias made landfall in southern North Carolina around 1110 PM EDT (0310 UTC) near Ocean Isle Beach, with maximum sustained winds of 85 mph (140 km/h).

A weather station at Oak Island, North Carolina, recently reported sustained winds of 76 mph (122 km/h) and a gust to 87 mph (140 km/h).

A data buoy near the coast of North Carolina has recently reported a minimum pressure of 988 MB (29.18 inches).

[Gaoth Laidir]

Some tornados have sprung up

...1200 PM EDT POSITION UPDATE...
...STRONG WINDS...HEAVY RAINFALL...AND TORNADOES OCCURRING OVER SOUTHERN NEW JERSEY AND SOUTHEASTERN PENNSYLVANIA WILL CONTINUE TO SPREAD NORTHWARD ALONG THE MID-ATLANTIC COAST THIS AFTERNOON...

A Weatherflow weather station at Long Beach Island Surf, New Jersey, recently reported a sustained wind of 46 mph (74 km/h) and a gust to 59 mph (94 km/h). Around 1053 AM EDT, this same weather observing station measured a wind gust of 109 mph (176 km/h), which was associated with a tornadic thunderstorm.

Doppler weather radar data from Ft. Dix, New Jersey, indicated Doppler velocities as high as 112 mph (180 km/h) at an altitude of 1,590 above ground level at this same location. However, this wind is not considered to be representative of Isaias' larger wind field.

Also, a Weatherflow observing site located at Rutgers/Little Egg Harbor, New Jersey, recently reported a sustained wind of 52 mph (84 km/h) and a gust to 70 mph (113 km/h).

SUMMARY OF 1200 PM EDT...1600 UTC...INFORMATION ----------------------------------------------- LOCATION...39.6N 75.8W
ABOUT 10 MI...20 KM WSW OF WILMINGTON DELAWARE
ABOUT 35 MI...55 KM WSW OF PHILADELPHIA PENNSYLVANIA
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...NNE OR 25 DEGREES AT 35 MPH...56 KM/H
MINIMUM CENTRAL PRESSURE...993 MB...29.32 INCHES

[hatrickpatrick]

Once Isaias burns out, we're likely to see a lull in activity lasting until August 10th or so, with the Atlantic floodgates potentially opening during the last fortnight of August as a large sinking cell settles over the Pacific and allows wind shear and surface pressures to drop in the tropical Atlantic.

[Gaoth Laidir]

Not quite hurricane-related but still along the same lines

From the BOM weekly update today

http://www.bom.gov.au/climate/mjo/#mjo7

Tropical cyclone activity over the western North Pacific Ocean
For the first time since at least 1949, no named storms (i.e. equivalent to a category 1 or stronger Australian tropical cyclone) developed in the western North Pacific basin in July 2020. In a typical year, this region sees between 3 and 4 tropical cyclones in July. This continues the well below-average tropical cyclone activity in the western North Pacific Ocean this year. Only one typhoon (equivalent to a category 3 Australian tropical cyclone) had been observed to the end of July 2020, compared to the long-term average of about 5.

In the past week, 2 named storms developed over the western North Pacific Ocean, bringing the 2020 total to 4 tropical storms, compared to an average of between 8 and 9.

Ex-tropical storm Sinlaku passed over Hainan Island and the east coast of northern Vietnam on 2 August as a weak tropical storm (equivalent to category 1 Australian tropical cyclone). Sinlaku generated strong winds and heavy rain as it made landfall. As it tracks further inland as a tropical depression, it is expected to produce heavy rains across parts of mainland China.

Typhoon Hagupit (Dindo) formed to the east of the Philippines and has recently tracked towards the north. It passed close to Taiwan in the last 24 hours and more recently made landfall on mainland China's east coast with mean winds estimated at more than 125 km/h.

The active MJO pulse over the Maritime Continent, along with another tropical atmospheric wave—an equatorial Rossy wave—contributed to the development of tropical cyclones Sinlaku and Hagupit.

[star gazer]

NOAA's Climate Prediction Centre has a projection for an 85% chance of an above normal hurricane season incuding 7 to 11 Hurricanes of which 3 to 6 Major Hurricanes. The hurricane season ends on the 30th November.
possible extremely active Atlantic hurricane season

“This year, we expect more, stronger, and longer-lived storms than average, and our predicted ACE range extends well above NOAA’s threshold for an extremely active season,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center.

Current oceanic and atmospheric conditions that make an “extremely active” hurricane season possible are warmer-than-average sea surface temperatures in the tropical Atlantic Ocean and Caribbean Sea, reduced vertical wind shear, weaker tropical Atlantic trade winds and an enhanced west African monsoon. These conditions are expected to continue for the next several months. A main climate factor behind these conditions is the ongoing warm phase of the Atlantic Multi-Decadal Oscillation, which reappeared in 1995 and has been favoring more active hurricane seasons since that time.

Another contributing climate factor this year is the possibility of La Nina developing in the months ahead. Indicative of cooler-than-average sea surface temperatures in the equatorial regions of the eastern Pacific Ocean, La Nina can further weaken the wind shear over the Atlantic Basin, allowing storms to develop and intensify.

ACE- Accumulated Cyclone Energy
The next three named storms: Josphine, Kyle, Laura

[Gaoth Laidir]

Tropical Depression 11 has formed in the MDR and will likely be named Josephine very soon. However, the max intensity forecast is 45 knots, after which conditions will become more hostile as it passes to the north of the Leeward Islands over the weekend, by which time it could well disintegrate into an open trough.

Meanwhile, Hurricane Elida in the eastern Pacific is currently 85 knots but will weaken rapidly as it passes over cold waters in the next day or so, staying well out to sea from southern Baja California.

[Gaoth Laidir]

TS Josephine has just been named and is the earliest 10th named Atlantic system on record. Next was Jose on August 22nd, 2005.

Currently intensity is 40 knots and slight strengthening to 50 knots is expected before it disintegrates to a tropical wave in about 3-5 days. It will stay clear of land.

[littlema]

Is anyone following TS Kyle which is heading NE from USA and could be wandering over the Atlantic ??

[Gaoth Laidir]

TS Kyle will not amount to much as it moves northeastwards in the western Atlantic. The official forecast has it peaking at 45 knots before dissipating by 5 days. Kyle is the earliest eleventh-named Atlantic system on record, with Katrina (2005) the the previous holder (22nd (August). Josephine is also on death row ąt 35 knots and aetiology to weaken and dissipate over the weekend.

Again, none or these systems has been anything of note, yielding a still low ACE total for the number of system. We're ahead of average on named storm numbers/days and hurricanes but still behind on major hurricanes.

ATLANTIC SEASON STATS SO FAR (14 AUG)

Named storms: 11 (average 2.8)
Named storm days: 25.25 (9.5)
Hurricanes: 2 (0.8)
Hurricane days: 3.0 (2.1)
Major hurricanes: 0 (0.3)
Major hurricane days: 0 (0.4)
Total ACE: 24.0 (12.0)

[Scrabbel]

ECM seems to show Kyle’s tail end, merged with another low, giving us a windy day on Friday.