5pm AST Thursday: 120mph; Tropical storm conditions beginning to spread over Turks and Caicos
Posted by Chris in Tampa
on 9/21/2017, 5:13 pm
Normal Satellite Floater:
Wider Atlantic views: http://www.ssd.noaa.gov/PS/TROP/trop-atl.html
GOES-16 1 minute mesoscale sector 1 floater (you can switch these to visible too):
Hurricane Maria Discussion Number 23
NWS National Hurricane Center Miami FL AL152017
500 PM AST Thu Sep 21 2017
The last pass of today's Air Force reconnaissance flight found
maximum flight-level winds of 117 kt in the northeastern eyewall,
which supported increasing the intensity to 105 kt in the 2 PM
intermediate advisory. The SFMR instrument continued to report
higher winds, as was mentioned in the previous discussion. However,
Maria has been moving over the Navidad and Silver Banks to the
north of the Dominican Republic, where water depths are less than
30 meters deep in some places, and it is likely that shoaling
effects inflated some of these numbers.
Maria continues to move northwestward, or 315/8 kt, around the
southwestern periphery of a mid-level high centered south of
Bermuda. As Maria moves around this high, and toward an elongated
trough extending from Tropical Storm Jose southwestward into the
Gulf of Mexico, it is expected to turn north-northwestward within
24 hours and then north-northeastward by the end of the forecast
period. This motion will take Maria's center very close to the
Turks and Caicos Islands and the southeastern Bahamas during the
next 24 hours, but the hurricane should then stay over the waters
of the western Atlantic through day 5. The track models remain
stable, and there is very little cross-track spread even at day 5.
The guidance has slowed down a bit by the end of the forecast
period due to Maria possibly interacting with a shortwave trough
moving off the southeastern U.S. coast, and the new NHC forecast is
therefore a little slower than the previous one at that time.
SHIPS diagnostics indicate that southwesterly shear will be
increasing over Maria during the next 12-24 hours, even though the
hurricane will begin to move over an area of higher oceanic heat
content. While it can't be ruled out that Maria might still
strengthen a bit, the preponderance of the guidance suggests that
the cyclone will only maintain its intensity for the next 12 hours
and then begin a gradual decrease in strength on Friday. That
trend should continue through the end of the forecast period, but
Maria is expected to remain a hurricane through day 5. For now,
the NHC forecast remains just above the intensity consensus,
hedging toward the slower decay shown by the SHIPS model.
1. Flash flood warnings continue in portions of Puerto Rico due
to persistent heavy rainfall from Maria's trailing rainbands.
Catastrophic flooding is occurring on the island, especially in
areas of mountainous terrain, and everyone in Puerto Rico should
continue to follow advice from local officials to avoid these
life-threatening flooding conditions.
2. A Hurricane Warning is in effect for the northern coast of the
Dominican Republic, the Turks and Caicos Islands, and the
southeastern Bahamas, where Maria is expected to bring dangerous
wind, storm surge, and heavy rainfall.
3. Swells from Maria are expected to begin reaching the coast of
the southeastern United States on Friday. These swells are likely
to cause dangerous surf and life-threatening rip currents along the
coast for the next several days, even with Maria forecast to remain
well offshore over the western Atlantic Ocean.
FORECAST POSITIONS AND MAX WINDS
INIT 21/2100Z 20.8N 69.8W 105 KT 120 MPH
12H 22/0600Z 21.6N 70.4W 105 KT 120 MPH
24H 22/1800Z 23.0N 71.2W 100 KT 115 MPH
36H 23/0600Z 24.5N 71.7W 100 KT 115 MPH
48H 23/1800Z 26.1N 72.1W 95 KT 110 MPH
72H 24/1800Z 28.9N 72.1W 95 KT 110 MPH
96H 25/1800Z 31.0N 71.0W 85 KT 100 MPH
120H 26/1800Z 33.0N 70.0W 75 KT 85 MPH
Hurricane Maria Advisory Number 23
NWS National Hurricane Center Miami FL AL152017
500 PM AST Thu Sep 21 2017
...TROPICAL STORM CONDITIONS BEGINNING TO SPREAD OVER THE TURKS AND
SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
ABOUT 90 MI...145 KM NE OF PUERTO PLATA DOMINICAN REPUBLIC
ABOUT 95 MI...155 KM ESE OF GRAND TURK ISLAND
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 315 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...960 MB...28.35 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
The government of the Dominican Republic has discontinued the
Tropical Storm Warning along the southern coast of the Dominican
Republic west of Cabo Engano.
SUMMARY OF WATCHES AND WARNINGS IN EFFECT:
A Hurricane Warning is in effect for...
* Dominican Republic from Cabo Engano to Puerto Plata
* Turks and Caicos Islands and the Southeastern Bahamas
A Tropical Storm Warning is in effect for...
* Dominican Republic west of Puerto Plata to the northern border of
the Dominican Republic and Haiti
A Tropical Storm Watch is in effect for...
* Central Bahamas
A Hurricane Warning means that hurricane conditions are expected
somewhere within the warning area. Preparations to protect life and
property should be rushed to completion.
A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area.
A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.
Interests elsewhere in Hispaniola and the Bahamas should monitor the
progress of Maria.
For storm information specific to your area, please monitor
products issued by your national meteorological service.
DISCUSSION AND 48-HOUR OUTLOOK
At 500 PM AST (2100 UTC), the large eye of Hurricane Maria was
located near latitude 20.8 North, longitude 69.8 West. Maria is
moving toward the northwest near 9 mph (15 km/h), and this general
motion is expected to continue through tonight. A turn toward the
north-northwest is forecast early Friday, with that motion
continuing through Saturday. On the forecast track, Maria's
eye will continue to pass offshore of the northern coast of the
Dominican Republic this evening, and then move near or just east of
the Turks and Caicos Islands and southeastern Bahamas tonight and on
Maximum sustained winds are near 120 mph (195 km/h) with higher
gusts. Maria is a category 3 hurricane on the Saffir-Simpson
Hurricane Wind Scale. Little change in strength is expected during
the next couple of days.
Hurricane-force winds extend outward up to 70 miles (110 km) from
the center, and tropical-storm-force winds extend outward up to 160
miles (260 km).
The estimated minimum central pressure is 960 mb (28.35 inches).
HAZARDS AFFECTING LAND
WIND: Hurricane and tropical storm conditions continue across
portions of the Dominican Republic. Tropical storm conditions are
beginning to spread across the Turks and Caicos Islands and the
southeastern Bahamas, and hurricane conditions are expected tonight
or early Friday. Tropical storm conditions are possible in the
central Bahamas beginning late Friday.
STORM SURGE: A dangerous storm surge accompanied by large and
destructive waves will raise water levels by as much as 4 to 6 feet
above normal tide levels in the hurricane warning area in the
Dominican Republic, and 1 to 3 ft elsewhere along the northern
coasts of the Dominican Republic and Haiti.
A dangerous storm surge accompanied by large and destructive waves
will raise water levels by as much as 9 to 12 feet above normal
tide levels within the hurricane warning area of the southeastern
Bahamas and the Turks and Caicos Islands.
RAINFALL: Maria is expected to produce the following rainfall
accumulations through Saturday:
Puerto Rico...additional 4 to 8 inches, isolated maximum storm total
amounts 40 inches
Northern and eastern Dominican Republic, Turks and Caicos, and
Mayaguana in southeast Bahamas...8 to 16 inches, isolated 20 inches
Inagua Islands, Crooked Island, and rest of southeast Bahamas...4 to
Northern Haiti...4 to 8 inches
Rainfall on these islands will continue to cause life-threatening
flash floods and mudslides.
SURF: Swells generated by Maria are affecting Puerto Rico, the
Virgin Islands, the northern coast of Hispaniola, the Turks and
Caicos Islands, and the southeastern Bahamas. These swells will
reach the remainder of the Bahamas tonight and should reach portions
of the United States southeastern coast on Friday. These swells are
likely to cause life-threatening surf and rip current conditions.
Please consult products from your local weather office.
Next intermediate advisory at 800 PM AST.
Next complete advisory at 1100 PM AST.
In this thread:
5pm AST Thursday: 120mph; Tropical storm conditions beginning to spread over Turks and Caicos - Chris in Tampa, 9/21/2017, 5:13 pm< Return to message board
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