Iceresistance Posted October 12, 2023 Posted October 12, 2023 (edited) EXTREMELY Strong Signal on the 12z Euro-Ensembles, including this 901 mb member NHC is in Spoiler Spoiler 1. Eastern Tropical Atlantic (AL94): Shower and thunderstorm activity remains limited and disorganized in association with a broad area of low pressure located several hundred miles south of the Cabo Verde Islands. Environmental conditions are expected to become more conducive for development of this system early next week, and a tropical depression could form by the middle of the week while moving westward or west-northwestward at about 10 mph across the eastern and central tropical Atlantic. * Formation chance through 48 hours...low...10 percent. * Formation chance through 7 days...medium...50 percent. Edited October 28, 2023 by StretchCT 1
Iceresistance Posted October 14, 2023 Author Posted October 14, 2023 (edited) Odds increasing, now all High at 70/90 Edited October 14, 2023 by Iceresistance
Moderators StretchCT Posted October 19, 2023 Moderators Posted October 19, 2023 Tropical Storm Tammy Advisory Number 6 NWS National Hurricane Center Miami FL AL202023 500 PM AST Thu Oct 19 2023 ...CENTER OF TAMMY EXPECTED TO APPROACH THE LEEWARD ISLANDS ON FRIDAY... ...TROPICAL STORM CONDITIONS AND HEAVY RAIN ARE EXPECTED IN PORTIONS OF THE LEEWARD ISLANDS BEGINNING FRIDAY... SUMMARY OF 500 PM AST...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...13.7N 56.6W ABOUT 200 MI...320 KM E OF BARBADOS ABOUT 300 MI...485 KM ESE OF MARTINIQUE MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H PRESENT MOVEMENT...WNW OR 285 DEGREES AT 13 MPH...20 KM/H MINIMUM CENTRAL PRESSURE...1001 MB...29.56 INCHES Tammy has a tight cluster for track, a good sign. All over with the intensity NHC forecast FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 13.7N 56.6W 50 KT 60 MPH 12H 20/0600Z 14.2N 58.2W 50 KT 60 MPH 24H 20/1800Z 15.0N 59.9W 55 KT 65 MPH 36H 21/0600Z 16.4N 61.4W 60 KT 70 MPH 48H 21/1800Z 17.9N 62.4W 65 KT 75 MPH 60H 22/0600Z 19.5N 63.1W 70 KT 80 MPH 72H 22/1800Z 21.0N 63.3W 75 KT 85 MPH 96H 23/1800Z 24.3N 62.3W 75 KT 85 MPH 120H 24/1800Z 28.5N 57.5W 75 KT 85 MPH
Moderators StretchCT Posted October 19, 2023 Moderators Posted October 19, 2023 A little concerned with HAFS A and it missing the trough HWRF scoops it up As does the GFS
Moderators StretchCT Posted October 23, 2023 Moderators Posted October 23, 2023 (edited) Wide envelope on this one this morning. Seems it misses the trough. Edited October 23, 2023 by StretchCT
Moderators StretchCT Posted October 24, 2023 Moderators Posted October 24, 2023 Still a lot of solutions for the track. \
Moderators StretchCT Posted October 25, 2023 Moderators Posted October 25, 2023 Seems Tammy wants to overperform, perhaps getting some inspiration from Otis. Now forecast to hit 105MPH. Spoiler Hurricane Tammy Discussion Number 28 NWS National Hurricane Center Miami FL AL202023 500 AM AST Wed Oct 25 2023 Satellite data indicate Tammy has strengthened this morning. Proxy-vis and infrared imagery depict a ragged eye has developed with deep convection wrapping around the center. There has been no microwave imagery this morning, but earlier SSMI/S and GMI images showed a tight inner core. The subjective Dvorak final-T intensity estimates have increased this cycle with a T5.0 and T4.5 from SAB and TAFB, respectively. Given the improved satellite imagery and using a blend of these estimates, the initial intensity is raised to 85 kt for this advisory. Although vertical wind shear is analyzed to have increased over the hurricane, the system is strengthening beneath upper-level divergence associated with a deep-layer trough over the western Atlantic. Models suggest some additional strengthening is possible over the next 12 hours or so, which is reflected in the NHC intensity forecast. Tammy is then expected to merge with a cold front, which is currently analyzed by TAFB and OPC just northwest of the system. Tammy is expected to undergo an extratropical transition, with this transition forecast to be complete within 24 hours. As this transition occurs Tammy's wind field will expand as it becomes a hurricane-force extratropical cyclone. Global models are in fairly good agreement that the cyclone will then weaken throughout the remainder of the forecast period. There is some potential it could shed its frontal structure this weekend, but for now the model-simulated satellite imagery does not show much increase in convection during that time. Tammy is moving northeastward at an estimated motion of 45 degrees at 9 knots, within the flow between a deep-layer trough over the western Atlantic and a subtropical ridge over the central Atlantic. Tammy is expected to turn northward later today, then move slowly northwestward in 2-3 days within weaker steering currents. The long-range forecast remains uncertain, with not much run-to-run model consistency and ensemble solutions that move in opposite directions. Given the uncertainty, there is little change from the previous forecast at this time range, with the NHC forecast track showing the cyclone slowing and meandering through the end of the the period. FORECAST POSITIONS AND MAX WINDS INIT 25/0900Z 25.6N 60.2W 85 KT 100 MPH 12H 25/1800Z 27.0N 59.4W 90 KT 105 MPH 24H 26/0600Z 28.9N 59.3W 75 KT 85 MPH...POST-TROP/EXTRATROP 36H 26/1800Z 30.0N 60.4W 65 KT 75 MPH...POST-TROP/EXTRATROP 48H 27/0600Z 30.6N 61.6W 60 KT 70 MPH...POST-TROP/EXTRATROP 60H 27/1800Z 31.0N 62.3W 55 KT 65 MPH...POST-TROP/EXTRATROP 72H 28/0600Z 31.3N 62.9W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 29/0600Z 31.2N 63.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 30/0600Z 31.0N 63.9W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Kelly Just as recently as the 5pm discussion yesterday, the top wind was forecast for 80mph. Spoiler Hurricane Tammy Discussion Number 26 NWS National Hurricane Center Miami FL AL202023 500 PM AST Tue Oct 24 2023 There have not been many changes in the satellite appearance of Tammy since the previous advisory. Bursts of convection continue to wrap around the estimated surface center. An AMSR2 microwave satellite pass at 1657 UTC showed a closed low-level circulation. While a couple of ASCAT passes showed surface winds less than hurricane strength, the resolution of the instrument likely cannot capture the peak winds in Tammy's small inner core. The initial intensity is held at 65 kt, closest to the TAFB satellite intensity estimate, though this could be generous. Simulated satellite imagery suggests Tammy could strengthen slightly within a day or so when the hurricane enters a region of enhanced upper-level divergence. Beyond this time frame, strong southwesterly shear, dry mid-level relative humidities, and cooling sea surface temperatures should cause Tammy to steadily weaken. Global models now indicate the hurricane should transition into a gale-force extratropical cyclone by 48 h, and this is reflected in the official intensity prediction. Tammy is moving to the northeast at about 7 kt. A mid-latitude trough should turn the hurricane north-northeastward and northward in a day or so. By Thursday, Tammy should bend to the northwest and slow down within the light steering currents between two ridges. A gradual westward turn is expected by the end of the forecast period. The latest NHC track prediction is slightly to the south of the previous advisory, and forward speed in the long-term forecast has been slowed. FORECAST POSITIONS AND MAX WINDS INIT 24/2100Z 24.6N 61.7W 65 KT 75 MPH 12H 25/0600Z 25.6N 60.7W 70 KT 80 MPH 24H 25/1800Z 27.5N 59.6W 70 KT 80 MPH 36H 26/0600Z 29.2N 59.4W 65 KT 75 MPH 48H 26/1800Z 30.4N 60.3W 55 KT 65 MPH...POST-TROP/EXTRATROP 60H 27/0600Z 31.1N 61.2W 50 KT 60 MPH...POST-TROP/EXTRATROP 72H 27/1800Z 31.6N 62.2W 50 KT 60 MPH...POST-TROP/EXTRATROP 96H 28/1800Z 32.0N 63.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 29/1800Z 32.0N 64.4W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ Forecaster Bucci
Moderators StretchCT Posted October 25, 2023 Moderators Posted October 25, 2023 Still crazy spread on the track.
Moderators StretchCT Posted October 25, 2023 Moderators Posted October 25, 2023 11:00 AM AST Wed Oct 25 Location: 26.6°N 59.3°W Moving: NE at 13 mph Min pressure: 965 mb Max sustained: 105 mph
Moderators StretchCT Posted October 25, 2023 Moderators Posted October 25, 2023 Tammy became a hurricane 5 days ago. Spoiler Hurricane Tammy Tropical Cyclone Update NWS National Hurricane Center Miami FL AL202023 1000 AM AST Fri Oct 20 2023 ...TAMMY BECOMES A HURRICANE... NOAA and Air Force Reserve hurricane hunter aircraft data indicate that Tammy has become a hurricane. The maximum winds are estimated to be 75 mph (120 km/h) with higher gusts. The initial and forecast intensities will be updated with the next advisory that will be issued at 1100 AM AST (1500 UTC). SUMMARY OF 1000 AM AST...1400 UTC...INFORMATION ----------------------------------------------- LOCATION...14.1N 58.5W ABOUT 90 MI...150 KM NE OF BARBADOS ABOUT 170 MI...275 KM ESE OF MARTINIQUE MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H PRESENT MOVEMENT...WNW OR 290 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...992 MB...29.29 INCHES $$ Forecaster Brown 1
Moderators StretchCT Posted October 25, 2023 Moderators Posted October 25, 2023 Tammy seems to have peaked. Nice discussion of the frontal interaction, limited outflow and erosion of the northern eyewall. I'll spare the rant on how an 80mph hurricane just becomes post-tropical while maintaining that strength. The discussion does mention the chance that Tammy regains tropical status. But it's path isn't quite certain and it would need to be over warmer waters. I don't get why they just don't keep it a hurricane or TS until it's demise. Spoiler Hurricane Tammy Discussion Number 30 NWS National Hurricane Center Miami FL AL202023 500 PM AST Wed Oct 25 2023 Tammy is beginning to interact with a front to its north. The eye has lost some of its definition as the northern eyewall slowly erodes. Outflow is now limited to the southern and eastern portions of the circulation. Subjective and objective satellite intensity estimates have fallen since the last advisory. Final T-numbers from SAB and TAFB are both T4.5 and ADT is down to T4.2. Given the recent degradation in satellite appearance, the initial intensity has been lowered to 85 kt. It appears that Tammy has moved out of the region with favorable upper-level dynamics. Strong upper-level winds and surrounding dry air are expected to steadily weaken the system through the forecast period. Model guidance shows that the hurricane should become entangled with the frontal feature to its north and transition into an extratropical cyclone within the next 24 hours. By 48 hours, the global models depict Tammy occluding and shedding its front. Therefore, the most recent NHC forecast shows the system as a post-tropical cyclone instead of extratropical beginning at day 2. There is a possibility that Tammy could regain tropical or subtropical status as the vortex meanders over sufficiently warm ocean waters during days 2 and 3. Tammy is still moving northeastward, but model guidance insists that the hurricane will make a turn to the north shortly. This is followed by a northwestward turn with a slower forward speed by Thursday. By Friday, Tammy is expected to meander over the northwestern Atlantic in the light steering currents between two building ridges over the eastern Atlantic and southeastern United States. The official NHC track forecast shows Tammy slowly turning back to the east by the weekend. However, more model guidance is showing a faster turn to the east resulting in a large spread in the track guidance envelope. The current forecast is on the western edge of the track solutions and is closest to the GFS. Further adjustments may be needed if these trends continue. FORECAST POSITIONS AND MAX WINDS INIT 25/2100Z 28.0N 57.9W 85 KT 100 MPH 12H 26/0600Z 29.5N 58.4W 80 KT 90 MPH 24H 26/1800Z 30.5N 59.4W 70 KT 80 MPH...POST-TROP/EXTRATROP 36H 27/0600Z 31.1N 60.4W 60 KT 70 MPH...POST-TROP/EXTRATROP 48H 27/1800Z 31.5N 61.1W 55 KT 65 MPH...POST-TROPICAL 60H 28/0600Z 31.8N 61.5W 50 KT 60 MPH...POST-TROPICAL 72H 28/1800Z 32.1N 61.7W 50 KT 60 MPH...POST-TROPICAL 96H 29/1800Z 32.5N 61.5W 45 KT 50 MPH...POST-TROPICAL 120H 30/1800Z 32.8N 61.0W 40 KT 45 MPH...POST-TROPICAL $$ Forecaster Bucci/R. Zelinsky
Moderators StretchCT Posted October 26, 2023 Moderators Posted October 26, 2023 The circle of uncertainty
Moderators StretchCT Posted October 26, 2023 Moderators Posted October 26, 2023 Last advisory, still 85mph. At least it's not around land, except Bermuda... and while it looks extratropical, the discussion mentions it's still warm core, and can regenerate into a tropical system. Do they hash it?
Moderators StretchCT Posted October 27, 2023 Moderators Posted October 27, 2023 And back to a Tropical Storm.
Moderators StretchCT Posted October 28, 2023 Moderators Posted October 28, 2023 11:00 AM AST Sat Oct 28 Location: 33.3°N 58.7°W Moving: E at 12 mph Min pressure: 995 mb Max sustained: 50 mph Should head east and weaken to depression/postropical tomorrow.
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