FLORIDA: Both Systems Staying Away.
BY: WEATHER TEAM | BocaNewsNow.com
BOCA RATON, FL (BocaNewsNow.com) (Copyright © 2021 MetroDesk Media, LLC) — The National Hurricane Center early this morning issued a tropical storm watch for Bermuda as strong hurricane Sam nears the area. Sam is still in the midst of a turn and no threat to Florida. The system is packing winds of 145 MPH.
Meantime, Tropical Storm Victor is also growing in strength. The system, which formed Wednesday, is also expected to maintain a path away from the United States mainland. Victor’s winds are 45 MPH and expected to increase to 75 MPH over the next day.
A third tropical system — expected just yesterday to form into a storm — is now unlikely to become much of anything. The system, marked by the yellow X above, has just a ten percent chance of development.
The following is the early morning update for Sam, followed by the update for Victor.
Hurricane Sam Discussion Number 31 NWS National Hurricane Center Miami FL AL182021 500 AM AST Thu Sep 30 2021 Sam is a very impressive hurricane in infrared satellite imagery this morning. The 25-nm-wide eye remains very distinct and is surrounded by a ring of convection with cloud tops around -65C. The outflow is also well established in all quadrants. An Air Force Reserve Hurricane Hunter aircraft that performed three eyewall penetrations overnight has reported peak 700-mb flight-level winds of 139 kt in the northeastern, southeastern, and eastern eyewall, and peak SFMR surface winds of 119 kt. These data still support an initial wind speed of 125 kt. Sam's minimum pressure has fallen a few millibars since the NOAA aircraft mission last evening. The latest estimated pressure from dropsonde data gathered by the Air Force is 937 mb. NOAA buoy 41044 has recently reported a peak one-minute wind of 68 kt with a gust to 86 kt in the northeastern eyewall of Sam. The buoy has also reported peak seas of 40 ft. Sam could still strengthen a little today as it continues to move over a warm ocean eddy and remains in low vertical wind shear conditions. After that time, difficult-to-predict eyewall cycles however, could cause some fluctuations in intensity. After 48 hours, gradually decreasing SSTs and ocean heat content are likely to cause a more definitive weakening trend, with a faster rate of weakening likely after day 3. Sam is forecast to complete its extratropical transition by day 5, and it is predicted by the global model guidance to become a large and powerful extratropical low over the north Atlantic. Sam is moving northwestward or 320/10 kt. The track forecast reasoning is again unchanged from the previous advisory. Sam will move northwestward, and then northward around the western portion of a subtropical ridge during the next 48 hours. After that time, Sam is predicted to turn northeastward between the ridge and a large mid-latitude trough over the northeastern United States. As that trough lifts northeastward by day 3, Sam is forecast to continue on a northeastward heading, but it is not likely to accelerate as much as a typical recurving tropical cyclone over the north-central Atlantic. The dynamical model guidance remains in excellent agreement through 72 hours, but there is increasing spread after that time. The latest runs of the GFS and ECMWF models have come into somewhat better agreement at days 3 through 5, and the NHC track forecast is near the consensus of those typically reliable models. Although the core of Sam is forecast to pass east of Bermuda early Saturday, the tropical-storm-force wind field is forecast to expand and could pass very close to the island beginning late Friday night or early Saturday. Therefore, the Bermuda Weather Service has issued a Tropical Storm Watch for Bermuda. Key Messages: 1. Swells generated by Sam will impact the Northern Leeward Islands and the Greater Antilles, including Puerto Rico, during the next few days. Swells are expected to reach Bermuda and the Bahamas by Friday, and then spread to the United States east coast by this weekend. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office. 2. Tropical storm conditions are possible on Bermuda beginning Friday night or early Saturday, and a Tropical Storm Watch has been issued for that island. FORECAST POSITIONS AND MAX WINDS INIT 30/0900Z 21.5N 59.1W 125 KT 145 MPH 12H 30/1800Z 23.0N 60.2W 130 KT 150 MPH 24H 01/0600Z 25.6N 61.4W 125 KT 145 MPH 36H 01/1800Z 28.4N 61.8W 120 KT 140 MPH 48H 02/0600Z 31.1N 61.3W 115 KT 130 MPH 60H 02/1800Z 33.5N 59.9W 105 KT 120 MPH 72H 03/0600Z 35.5N 58.0W 95 KT 110 MPH 96H 04/0600Z 38.7N 52.6W 80 KT 90 MPH 120H 05/0600Z 44.3N 45.0W 65 KT 75 MPH...POST-TROP/EXTRATROP
Tropical Storm Victor Discussion Number 4 NWS National Hurricane Center Miami FL AL202021 800 AM CVT Thu Sep 30 2021 Victor is gradually getting better organized. AMSR2 microwave data from 0300 UTC showed that the low-level circulation has become more defined, with most convective banding features located west and southwest of the center. Victor's intensity is now estimated to be 40 kt based on Dvorak estimates of T3.0 and T2.5 from TAFB and SAB, respectively, and objective numbers from UW-CIMSS around 40 kt. Victor's vector is toward the west-northwest (290 degrees) at 11 kt, and this heading should continue for the next 36 hours while the storm is located to the south a deep-layer ridge located over the subtropical eastern and central Atlantic. In about 2 days, a mid- to upper-level low is forecast to develop over the central Atlantic, causing Victor to curve around the western periphery of the ridge, which gets shunted eastward between the Azores and the Canary Islands. The track models are in generally good agreement on this scenario, and most of them are clustered tightly among each other. Two notable exceptions, which are discounted at this time, are the HWRF and ECMWF models. The HWRF, which is stronger than the other models, is way off to the east, while the ECMWF lies off to the south and west, a tendency that we've observed recently with other storms in the deep tropics. The NHC track forecast is not changed much from the previous iteration and lies close to the GFS, HCCA, Florida State Superensemble, and TVCA solutions. If the low-level circulation is in fact becoming better defined as shown by microwave imagery, Victor should be able to continue strengthening for the next couple of days in an environment of low vertical shear and over warm waters of roughly 28 degrees Celsius. The NHC intensity forecast is near the upper end of the guidance during this period and continues to show Victor reaching hurricane strength in about 36 hours. Once the aforementioned mid- to upper-level low forms, strong southerly to southwesterly deep-layer shear is expected to develop over Victor and induce a weakening trend in about 3 days. The intensity forecast has been lowered a bit during the latter part of the forecast period given the trends in the intensity models, but it is not as low as the HCCA and IVCN aids. Interestingly, many of the global models suggest that the shear could be so strong that Victor might weaken to a depression or even degenerate into a remnant low by day 5. FORECAST POSITIONS AND MAX WINDS INIT 30/0900Z 8.7N 27.3W 40 KT 45 MPH 12H 30/1800Z 9.4N 28.8W 50 KT 60 MPH 24H 01/0600Z 10.2N 30.6W 60 KT 70 MPH 36H 01/1800Z 11.2N 32.3W 65 KT 75 MPH 48H 02/0600Z 12.6N 33.8W 65 KT 75 MPH 60H 02/1800Z 14.4N 35.3W 60 KT 70 MPH 72H 03/0600Z 16.6N 37.0W 55 KT 65 MPH 96H 04/0600Z 22.0N 40.2W 40 KT 45 MPH 120H 05/0600Z 27.3N 41.9W 35 KT 40 MPH
