Weather
Post-Tropical Cyclone Helene Forecast Advisory Number 18
Issued at 2100 UTC FRI SEP 27 2024
539
WTNT24 KNHC 272034
TCMAT4
POST-TROPICAL CYCLONE HELENE FORECAST/ADVISORY NUMBER 18
NWS NATIONAL HURRICANE CENTER MIAMI FL AL092024
2100 UTC FRI SEP 27 2024
POST-TROPICAL CYCLONE CENTER LOCATED NEAR 37.5N 85.5W AT 27/2100Z
POSITION ACCURATE WITHIN 30 NM
PRESENT MOVEMENT TOWARD THE NORTH-NORTHWEST OR 330 DEGREES AT 15 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 984 MB
MAX SUSTAINED WINDS 30 KT WITH GUSTS TO 40 KT.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.
REPEAT...CENTER LOCATED NEAR 37.5N 85.5W AT 27/2100Z
AT 27/1800Z CENTER WAS LOCATED NEAR 36.7N 84.9W
FORECAST VALID 28/0600Z 37.9N 87.0W...POST-TROP/EXTRATROP
MAX WIND 25 KT...GUSTS 35 KT.
FORECAST VALID 28/1800Z 37.7N 87.2W...POST-TROP/EXTRATROP
MAX WIND 20 KT...GUSTS 30 KT.
FORECAST VALID 29/0600Z 37.5N 87.3W...POST-TROP/EXTRATROP
MAX WIND 20 KT...GUSTS 30 KT.
FORECAST VALID 29/1800Z 37.3N 87.0W...POST-TROP/EXTRATROP
MAX WIND 20 KT...GUSTS 30 KT.
FORECAST VALID 30/1800Z...DISSIPATED
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 37.5N 85.5W
THIS IS THE LAST FORECAST/ADVISORY ISSUED BY THE NATIONAL HURRICANE
CENTER ON THIS SYSTEM. FUTURE INFORMATION ON THIS SYSTEM CAN BE
FOUND IN FORECAST/ADVISORIES ISSUED BY THE WEATHER PREDICTION CENTER
BEGINNING AT 0300 UTC, UNDER AWIPS HEADER TCMAT4, WMO HEADER
WTNT24 KWNH, AND ON THE WEB AT WWW.HURRICANES.GOV.
RAINFALL FORECASTS FOR THE UNITED STATES CAN ALWAYS BE FOUND AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/QPF2.SHTML
AND OUTLOOKS OF FLASH FLOOD RISKS CAN BE FOUND AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/EXCESSIVE_RAINFALL_OUTLOOK_ERO.PHP
.
$$
FORECASTER CANGIALOSI
Categories: Weather
Hurricane Isaac Forecast Discussion Number 8
Issued at 500 PM AST Fri Sep 27 2024
537
WTNT45 KNHC 272034
TCDAT5
Hurricane Isaac Discussion Number 8
NWS National Hurricane Center Miami FL AL102024
500 PM AST Fri Sep 27 2024
Isaac's satellite presentation has improved since this morning. A
small ragged eye can be seen on infrared imagery with cooler cloud
tops surrounding it. An AMSR2 microwave pass from earlier today
showed the mid- and low-level centers co-located with a primary
band in the northwestern quadrant. Both the SAB and TAFB subjective
Dvorak classifications suggested that Isaac's intensity has
increased. Objective guidance aids are also suggesting the same.
Taking all of these into consideration, the intensity has been
increased to 75 kt.
The hurricane is moving eastward at 14 kt. Isaac is moving in the
mid-latitude zonal flow and will gradual turn to the east-northeast
later today. In about a day or so, Isaac will begin interacting with
an upper-level trough to its east and turn more northeastward and
slow down. The latest track forecast is very similar to the previous
forecast, however, the day four and five track positions were
adjusted westward as the model guidance has been shifting in this
direction.
Isaac is close to its peak intensity as the window for strengthening
is ending soon. By Saturday, it will move over cooler waters, into
an area of strong vertical wind shear, and a dry mid-level airmass.
The peak intensity has been adjusted upward to 80 kt because of the
recent strengthening. On Saturday, Isaac is expect to gradually
weaken and this trend will continue for the reminder of the forecast
period. Simulated satellite imagery from the global models show
Isaac losing its deep convection by Monday and the official forecast
now predicts the hurricane to become a post-tropical cyclone by 60
h.
FORECAST POSITIONS AND MAX WINDS
INIT 27/2100Z 37.8N 45.3W 75 KT 85 MPH
12H 28/0600Z 38.8N 42.7W 80 KT 90 MPH
24H 28/1800Z 40.3N 39.8W 75 KT 85 MPH
36H 29/0600Z 41.8N 37.9W 70 KT 80 MPH
48H 29/1800Z 43.1N 36.3W 65 KT 75 MPH
60H 30/0600Z 44.4N 34.5W 60 KT 70 MPH...POST-TROPICAL
72H 30/1800Z 45.7N 32.7W 50 KT 60 MPH...POST-TROPICAL
96H 01/1800Z 50.1N 29.9W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 02/1800Z 52.9N 27.3W 35 KT 40 MPH...POST-TROP/EXTRATROP
$$
Forecaster Bucci/Rosado
Categories: Weather
Summary for Hurricane Isaac (AT5/AL102024)
...ISAAC IS INTENSIFYING...
As of 5:00 PM AST Fri Sep 27
the center of Isaac was located near 37.8, -45.3
with movement E at 16 mph.
The minimum central pressure was 976 mb
with maximum sustained winds of about 85 mph.
Categories: Weather
Hurricane Isaac Public Advisory Number 8
Issued at 500 PM AST Fri Sep 27 2024
000
WTNT35 KNHC 272034
TCPAT5
BULLETIN
Hurricane Isaac Advisory Number 8
NWS National Hurricane Center Miami FL AL102024
500 PM AST Fri Sep 27 2024
...ISAAC IS INTENSIFYING...
SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...37.8N 45.3W
ABOUT 995 MI...1600 KM W OF THE AZORES
MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H
PRESENT MOVEMENT...E OR 80 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...976 MB...28.82 INCHES
WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.
DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Hurricane Isaac was located
near latitude 37.8 North, longitude 45.3 West. Isaac is moving
toward the east near 16 mph (26 km/h). A gradual turn to the
east-northeast is expected with a slight decrease in forward speed
over the next day or so. On Saturday, a gradual turn to the
northeast is forecast and this motion should continue through
Monday.
Maximum sustained winds have increased to near 85 mph (140 km/h)
with higher gusts. Some slight additional strengthening is expected
tonight or Saturday morning followed by gradual weakening through
early next week. Isaac is expected to be a post-tropical cyclone on
Monday.
Hurricane-force winds extend outward up to 15 miles (30 km) from the
center and tropical-storm-force winds extend outward up to 90 miles
(150 km).
The estimated minimum central pressure is 976 mb (28.82 inches).
HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Isaac and a large wind fetch from a
deep-layer trough could spread into the Azores by this weekend.
These swells are likely to cause life-threatening surf and rip
current conditions. Please consult products from your local weather
office.
NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.
$$
Forecaster Bucci/Rosado
Categories: Weather
Hurricane Isaac Wind Speed Probabilities Number 8
Issued at 2100 UTC FRI SEP 27 2024
000
FONT15 KNHC 272034
PWSAT5
HURRICANE ISAAC WIND SPEED PROBABILITIES NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024
2100 UTC FRI SEP 27 2024
AT 2100Z THE CENTER OF HURRICANE ISAAC WAS LOCATED NEAR LATITUDE
37.8 NORTH...LONGITUDE 45.3 WEST WITH MAXIMUM SUSTAINED WINDS NEAR
75 KTS...85 MPH...140 KM/H.
Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH)
ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME
EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME
CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME
WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS
CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST
...34 KT (39 MPH... 63 KM/H)...
...50 KT (58 MPH... 93 KM/H)...
...64 KT (74 MPH...119 KM/H)...
FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS
PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE
OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING
AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY)
(CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN
18Z FRI AND THE FORECAST HOUR (CUMULATIVE PROBABILITY)
PROBABILITIES ARE GIVEN IN PERCENT
X INDICATES PROBABILITIES LESS THAN 1 PERCENT
PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN
THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT.
PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY
64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT.
- - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - -
FROM FROM FROM FROM FROM FROM FROM
TIME 18Z FRI 06Z SAT 18Z SAT 06Z SUN 18Z SUN 18Z MON 18Z TUE
PERIODS TO TO TO TO TO TO TO
06Z SAT 18Z SAT 06Z SUN 18Z SUN 18Z MON 18Z TUE 18Z WED
FORECAST HOUR (12) (24) (36) (48) (72) (96) (120)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
LOCATION KT
SANTA CRUZ AZO 34 X X( X) 1( 1) 2( 3) 2( 5) X( 5) X( 5)
$$
FORECASTER BUCCI
Categories: Weather
Hurricane Isaac Forecast Advisory Number 8
Issued at 2100 UTC FRI SEP 27 2024
000
WTNT25 KNHC 272033
TCMAT5
HURRICANE ISAAC FORECAST/ADVISORY NUMBER 8
NWS NATIONAL HURRICANE CENTER MIAMI FL AL102024
2100 UTC FRI SEP 27 2024
HURRICANE CENTER LOCATED NEAR 37.8N 45.3W AT 27/2100Z
POSITION ACCURATE WITHIN 30 NM
PRESENT MOVEMENT TOWARD THE EAST OR 80 DEGREES AT 14 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 976 MB
EYE DIAMETER 20 NM
MAX SUSTAINED WINDS 75 KT WITH GUSTS TO 90 KT.
64 KT....... 0NE 15SE 10SW 0NW.
50 KT....... 20NE 40SE 30SW 20NW.
34 KT....... 40NE 80SE 70SW 60NW.
12 FT SEAS.. 90NE 180SE 180SW 90NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.
REPEAT...CENTER LOCATED NEAR 37.8N 45.3W AT 27/2100Z
AT 27/1800Z CENTER WAS LOCATED NEAR 37.5N 46.2W
FORECAST VALID 28/0600Z 38.8N 42.7W
MAX WIND 80 KT...GUSTS 100 KT.
64 KT... 10NE 20SE 15SW 10NW.
50 KT... 30NE 50SE 40SW 30NW.
34 KT... 80NE 100SE 80SW 80NW.
FORECAST VALID 28/1800Z 40.3N 39.8W
MAX WIND 75 KT...GUSTS 90 KT.
64 KT... 15NE 20SE 15SW 10NW.
50 KT... 40NE 50SE 40SW 40NW.
34 KT...120NE 120SE 100SW 100NW.
FORECAST VALID 29/0600Z 41.8N 37.9W
MAX WIND 70 KT...GUSTS 85 KT.
64 KT... 0NE 20SE 15SW 0NW.
50 KT... 40NE 55SE 50SW 40NW.
34 KT...170NE 130SE 110SW 120NW.
FORECAST VALID 29/1800Z 43.1N 36.3W
MAX WIND 65 KT...GUSTS 80 KT.
64 KT... 0NE 0SE 20SW 0NW.
50 KT... 40NE 60SE 55SW 50NW.
34 KT...180NE 130SE 110SW 160NW.
FORECAST VALID 30/0600Z 44.4N 34.5W...POST-TROPICAL
MAX WIND 60 KT...GUSTS 75 KT.
50 KT... 40NE 55SE 45SW 45NW.
34 KT...180NE 130SE 110SW 180NW.
FORECAST VALID 30/1800Z 45.7N 32.7W...POST-TROPICAL
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 0NE 50SE 35SW 30NW.
34 KT...180NE 130SE 110SW 160NW.
EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 125 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY
OUTLOOK VALID 01/1800Z 50.1N 29.9W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...190NE 110SE 90SW 110NW.
OUTLOOK VALID 02/1800Z 52.9N 27.3W...POST-TROP/EXTRATROP
MAX WIND 35 KT...GUSTS 45 KT.
34 KT...190NE 180SE 80SW 0NW.
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 37.8N 45.3W
NEXT ADVISORY AT 28/0300Z
$$
FORECASTER BUCCI
Categories: Weather
Local Statement for Greenville-Spartanburg, SC
Issued at 228 PM EDT Fri Sep 27 2024
Categories: Weather
Atlantic Tropical Weather Outlook
000
ABNT20 KNHC 271752
TWOAT
Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Fri Sep 27 2024
For the North Atlantic...Caribbean Sea and the Gulf of Mexico:
Active Systems:
The National Hurricane Center is issuing advisories on Tropical
Depression Helene, located inland over the southern Appalachians,
on Hurricane Isaac, located over the central Subtropical Atlantic
Ocean, and on recently-formed Tropical Storm Joyce, located over
the central Tropical Atlantic Ocean.
Western Caribbean:
An area of low pressure could form over the western Caribbean Sea by
the middle of next week. Environmental conditions are expected to be
conducive for slow development thereafter while the system moves
generally northwestward, potentially entering the Gulf of Mexico by
the end of next week.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...30 percent.
Eastern Tropical Atlantic:
An area of low pressure could form over the eastern tropical
Atlantic by the early to middle part of next week. Environmental
conditions are expected to be conducive for slow development
thereafter while the system moves generally northwestward at 10 to
15 mph.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...low...30 percent.
&&
Public Advisories on Tropical Storm Joyce are issued under WMO
header WTNT31 KNHC and under AWIPS header MIATCPAT1.
Forecast/Advisories on Tropical Storm Joyce are issued under WMO
header WTNT21 KNHC and under AWIPS header MIATCMAT1.
$$
Forecaster Bucci/Rosado
Categories: Weather
Tropical Depression Helene Graphics
5-Day Uncertainty Track last updated Fri, 27 Sep 2024 17:48:15 GMT
Wind Speed Probabilities last updated Fri, 27 Sep 2024 15:23:05 GMT
Categories: Weather
Summary for Tropical Depression Helene (AT4/AL092024)
...HELENE STILL PRODUCING HISTORIC AND CATASTROPHIC FLOODING OVER PORTIONS OF THE SOUTHEAST AND SOUTHERN APPALACHIANS...
As of 2:00 PM EDT Fri Sep 27
the center of Helene was located near 36.6, -84.6
with movement NNW at 28 mph.
The minimum central pressure was 982 mb
with maximum sustained winds of about 35 mph.
Categories: Weather
Tropical Depression Helene Public Advisory Number 17A
Issued at 200 PM EDT Fri Sep 27 2024
000
WTNT34 KNHC 271746
TCPAT4
BULLETIN
Tropical Depression Helene Intermediate Advisory Number 17A
NWS National Hurricane Center Miami FL AL092024
200 PM EDT Fri Sep 27 2024
...HELENE STILL PRODUCING HISTORIC AND CATASTROPHIC FLOODING OVER
PORTIONS OF THE SOUTHEAST AND SOUTHERN APPALACHIANS...
SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...36.6N 84.6W
ABOUT 125 MI...205 KM SSE OF LOUISVILLE KENTUCKY
MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H
PRESENT MOVEMENT...NNW OR 330 DEGREES AT 28 MPH...44 KM/H
MINIMUM CENTRAL PRESSURE...982 MB...29.00 INCHES
WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:
All Tropical Storm Warnings have been discontinued.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
There are no coastal watches or warnings in effect.
For storm information specific to your area, please monitor
products issued by your local National Weather Service forecast
office.
DISCUSSION AND OUTLOOK
----------------------
At 200 PM EDT (1800 UTC), the center of Tropical Depression Helene
was located near latitude 36.6 North, longitude 84.6 West. Helene is
moving toward the north-northwest near 28 mph (44 km/h). A slowdown
in forward speed is expected, and the depression is forecast to
stall over the Tennessee Valley tonight and through the weekend.
Maximum sustained winds have decreased to near 35 mph (55 km/h)
with higher gusts. Continued slow weakening is expected, and
Helene is forecast to become extratropical later this afternoon.
The estimated minimum central pressure based on surface
observations is 982 mb (29.00 inches).
HAZARDS AFFECTING LAND
----------------------
Key Messages for Helene can be found in the Tropical Cyclone
Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC
and on the web at hurricanes.gov/text/MIATCDAT4.shtml
STORM SURGE: Water levels will continue to recede along the Florida
Gulf Coast and portions of the southeast U.S. coast throughout the
day.
WIND: Gusts to tropical-storm-force are still occurring in portions
of the Appalachians and off the South Carolina coast, but they
should subside by this evening.
RAINFALL: Over portions of the Central and Southern Appalachians,
Helene is expected to produce additional rainfall amounts of 3 to 6
inches leading to total rain accumulations of 6 to 12 inches, with
isolated totals around 20 inches. This rainfall will result in
catastrophic and potentially life-threatening flash and urban
flooding, along with significant and record river flooding. Numerous
significant landslides are expected in steep terrain across the
Southern Appalachians.
For a complete depiction of forecast rainfall associated with
Helene, please see the National Weather Service Storm Total Rainfall
Graphic, available at hurricanes.gov/graphics_at4.shtml?rainqpf and
the Flash Flood Risk
graphic at hurricanes.gov/graphics_at4.shtml?ero.
For a list of rainfall observations (and wind reports) associated
this storm, see the companion storm summary at WBCSCCNS4 with the
WMO header ACUS44 KWBC or at the following link:
www.wpc.ncep.noaa.gov/discussions/nfdscc4.html
TORNADOES: Tornadoes are possible today across eastern South
Carolina, central and eastern North Carolina, and southern Virginia.
SURF: Swells generated by Helene will affect the coasts of Georgia
and the Carolinas during the next day or so. These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.
NEXT ADVISORY
-------------
Next complete advisory at 500 PM EDT.
$$
Forecaster Cangialosi
Categories: Weather
Tropical Storm Joyce Graphics
5-Day Uncertainty Track last updated Fri, 27 Sep 2024 14:41:53 GMT
Wind Speed Probabilities last updated Fri, 27 Sep 2024 15:37:27 GMT
Categories: Weather
Hurricane Isaac Graphics
5-Day Uncertainty Track last updated Fri, 27 Sep 2024 14:39:39 GMT
Wind Speed Probabilities last updated Fri, 27 Sep 2024 15:30:31 GMT
Categories: Weather
Summary for Hurricane Isaac (AT5/AL102024)
...HURRICANE ISAAC HEADING EASTWARD OVER THE NORTH CENTRAL ATLANTIC OCEAN...
As of 11:00 AM AST Fri Sep 27
the center of Isaac was located near 37.4, -46.8
with movement ENE at 18 mph.
The minimum central pressure was 981 mb
with maximum sustained winds of about 75 mph.
Categories: Weather
Hurricane Isaac Public Advisory Number 7
Issued at 1100 AM AST Fri Sep 27 2024
535
WTNT35 KNHC 271438 CCA
TCPAT5
BULLETIN
Hurricane Isaac Advisory Number 7...Corrected
NWS National Hurricane Center Miami FL AL102024
1100 AM AST Fri Sep 27 2024
Correct headline
...HURRICANE ISAAC HEADING EASTWARD OVER THE NORTH CENTRAL ATLANTIC
OCEAN...
SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...37.4N 46.8W
ABOUT 1080 MI...1740 KM W OF THE AZORES
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...ENE OR 65 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...981 MB...28.97 INCHES
WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.
DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the center of Hurricane Isaac was located
near latitude 37.4 North, longitude 46.8 West. Isaac is moving
toward the east-northeast near 18 mph (30 km/h). A gradual turn to
the east-northeast with a slight acceleration in forward speed is
expected over the few days.
Maximum sustained winds are near 75 mph (120 km/h) with higher
gusts. Additional strengthening is expected during the next day or
so followed by gradual weakening by the end of this weekend.
Hurricane-force winds extend outward up to 15 miles (30 km) from the
center and tropical-storm-force winds extend outward up to 70 miles
(110 km).
The estimated minimum central pressure is 981 mb (28.97 inches).
HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Isaac and a large wind fetch from a
deep-layer trough could spread into the Azores by this weekend.
These swells are likely to cause life-threatening surf and rip
current conditions. Please consult products from your local weather
office.
NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.
$$
Forecaster Bucci
Categories: Weather
Tropical Storm Joyce Forecast Discussion Number 1
Issued at 1100 AM AST Fri Sep 27 2024
000
WTNT41 KNHC 271438
TCDAT1
Tropical Storm Joyce Discussion Number 1
NWS National Hurricane Center Miami FL AL112024
1100 AM AST Fri Sep 27 2024
Tropical Storm Joyce has formed over the central tropical Atlantic
Ocean, becoming the tenth named storm in the basin this season.
First-light visible satellite imagery showed low-level clouds
moving westward, indicating the surface circulation has closed.
Deep, organized convection has been persistent for the past day or
so with decent outflow noted in the northern semicircle of the
circulation. This initial intensity is set to 35 kt, representing
the subjective satellite estimates from both TAFB and SAB.
Joyce has a short window for potential intensification. For the
next day or so, deep-layer vertical wind shear should be
moderate-to-low with warm sea surface temperatures along the
forecast track. Mid-level humidities around Joyce are sufficient,
but expected to dry in the coming days. Global models predict the
vertical wind shear should increase and the storm will likely
experience dry air intrusions. The official forecast shows Joyce
strengthening to a peak of 50 kt on Saturday, followed by gradual
weakening through next week. Deep convection should be stripped
away by Tuesday and Joyce is expected to become a remnant low
at that point before opening into a trough. However, the GFS
suggests this could happen even sooner.
The storm is moving northwestward at 11 kt. A weak mid-level ridge
centered over the eastern Atlantic Ocean is expected to steer Joyce
generally northwestward for the next day or so, followed by a
gradual turn to the north-northwest and north with a slowing forward
speed. Model guidance is in relatively good agreement about this
evolution and the NHC track forecast follows the various simple and
corrected consensus aids.
FORECAST POSITIONS AND MAX WINDS
INIT 27/1500Z 18.1N 42.9W 35 KT 40 MPH
12H 28/0000Z 18.8N 44.3W 40 KT 45 MPH
24H 28/1200Z 19.4N 46.1W 50 KT 60 MPH
36H 29/0000Z 19.8N 47.7W 45 KT 50 MPH
48H 29/1200Z 20.7N 48.8W 40 KT 45 MPH
60H 30/0000Z 21.6N 49.4W 40 KT 45 MPH
72H 30/1200Z 22.6N 49.4W 35 KT 40 MPH
96H 01/1200Z 23.9N 48.8W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 02/1200Z...DISSIPATED
$$
Forecaster Bucci
Categories: Weather