|
NHC Atlantic |
| Active tropical cyclones in the Atlantic, Caribbean, and the Gulf of Mexico
|
Atlantic Tropical Weather Outlook
|
|
000
ABNT20 KNHC 161745
TWOAT
Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Wed Aug 16 2017
For the North Atlantic...Caribbean Sea and the Gulf of Mexico:
The National Hurricane Center is issuing advisories on Hurricane
Gert, located a few hundred miles north of Bermuda.
A low pressure system located about 800 miles east of the Lesser
Antilles has become a little better defined since yesterday, but
most of the associated shower and thunderstorm activity is
displaced to the west of the center of circulation. Upper-level
winds are forecast to become more conducive for development during
the next day or so while the low moves westward at 15 to 20 mph
across the tropical Atlantic Ocean, crossing into the Caribbean Sea
on Friday. An Air Force Reserve reconnaissance aircraft is
scheduled to investigate this system on Thursday, if necessary, and
interests in the Lesser Antilles should monitor the progress of the
disturbance.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...50 percent.
A second area of low pressure is located about 800 miles west
of the Cabo Verde Islands, and its associated shower and
thunderstorm activity remains disorganized. Gradual development of
this system is possible during the next few days while it moves
west-northwestward at 15 to 20 mph, but upper-level winds are
expected to become less conducive for tropical cyclone formation
when the disturbance moves north of the Leeward Islands this
weekend.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...50 percent.
A tropical wave near the west coast of Africa is producing a
large area of disorganized showers and thunderstorms.
Environmental conditions appear conducive for gradual development of
this wave while it moves westward to west-northwestward at about 15
mph during the next several days.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 5 days...medium...40 percent.
$$
Forecaster Berg
|
Summary for Hurricane Gert (AT3/AL082017)
|
|
...GERT BECOMES A CATEGORY 2 HURRICANE OVER THE NORTHWESTERN ATLANTIC...
As of 5:00 PM AST Wed Aug 16
the center of Gert was located near 38.7, -62.4
with movement NE at 31 mph.
The minimum central pressure was 970 mb
with maximum sustained winds of about 100 mph.
|
Hurricane Gert Public Advisory Number 16
|
Issued at 500 PM AST Wed Aug 16 2017
000
WTNT33 KNHC 162032
TCPAT3
BULLETIN
Hurricane Gert Advisory Number 16
NWS National Hurricane Center Miami FL AL082017
500 PM AST Wed Aug 16 2017
...GERT BECOMES A CATEGORY 2 HURRICANE OVER THE NORTHWESTERN
ATLANTIC...
SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...38.7N 62.4W
ABOUT 410 MI...665 KM S OF HALIFAX NOVA SCOTIA
ABOUT 725 MI...1170 KM SW OF CAPE RACE NEWFOUNDLAND
MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H
PRESENT MOVEMENT...NE OR 55 DEGREES AT 31 MPH...50 KM/H
MINIMUM CENTRAL PRESSURE...970 MB...28.65 INCHES
WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.
DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
At 500 PM AST (2100 UTC), the center of Hurricane Gert was located
near latitude 38.7 North, longitude 62.4 West. Gert is moving
quickly toward the northeast near 31 mph (50 km/h). An even faster
motion toward the east-northeast is expected through Thursday,
followed by some deceleration and a turn toward the northeast
Thursday night and Friday.
Maximum sustained winds have increased to near 100 mph (155 km/h)
with higher gusts. Little change in strength is expected through
tonight, but weakening is forecast to begin on Thursday. Gert
should become an extratropical low by early Friday.
Hurricane-force winds extend outward up to 35 miles (55 km) from the
center, and tropical-storm-force winds extend outward up to 140
miles (220 km).
The estimated minimum central pressure is 970 mb (28.65 inches).
HAZARDS AFFECTING LAND
----------------------
SURF: Swells generated by Gert will spread northward along the
east coast of the United States from Virginia northward to
New England and Atlantic Canada during the next day or two.
Swells are also expected to continue to affect Bermuda through
tonight. These swells are likely to cause life-threatening surf and
rip current conditions. Please consult products from your local
weather forecast office.
NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.
$$
Forecaster Berg
|
Hurricane Gert Forecast Advisory Number 16
|
Issued at 2100 UTC WED AUG 16 2017
000
WTNT23 KNHC 162032
TCMAT3
HURRICANE GERT FORECAST/ADVISORY NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL AL082017
2100 UTC WED AUG 16 2017
THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT.
HURRICANE CENTER LOCATED NEAR 38.7N 62.4W AT 16/2100Z
POSITION ACCURATE WITHIN 20 NM
PRESENT MOVEMENT TOWARD THE NORTHEAST OR 55 DEGREES AT 27 KT
ESTIMATED MINIMUM CENTRAL PRESSURE 970 MB
EYE DIAMETER 10 NM
MAX SUSTAINED WINDS 85 KT WITH GUSTS TO 105 KT.
64 KT....... 30NE 30SE 0SW 0NW.
50 KT....... 50NE 60SE 30SW 20NW.
34 KT....... 90NE 120SE 80SW 50NW.
12 FT SEAS..120NE 240SE 180SW 150NW.
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 38.7N 62.4W AT 16/2100Z
AT 16/1800Z CENTER WAS LOCATED NEAR 38.2N 64.1W
FORECAST VALID 17/0600Z 40.7N 56.9W
MAX WIND 85 KT...GUSTS 105 KT.
64 KT... 30NE 35SE 15SW 0NW.
50 KT... 50NE 70SE 40SW 30NW.
34 KT... 90NE 140SE 110SW 60NW.
FORECAST VALID 17/1800Z 44.3N 48.2W
MAX WIND 70 KT...GUSTS 85 KT.
64 KT... 20NE 35SE 20SW 0NW.
50 KT... 40NE 70SE 50SW 0NW.
34 KT... 90NE 150SE 120SW 60NW.
FORECAST VALID 18/0600Z 48.3N 40.4W
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 30NE 60SE 30SW 0NW.
34 KT...110NE 150SE 120SW 60NW.
FORECAST VALID 18/1800Z 51.6N 35.7W...POST-TROP/EXTRATROP
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...150NE 180SE 150SW 60NW.
FORECAST VALID 19/1800Z 54.3N 32.6W...POST-TROP/EXTRATROP
MAX WIND 40 KT...GUSTS 50 KT.
34 KT...180NE 120SE 150SW 150NW.
EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 200 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY
OUTLOOK VALID 20/1800Z...ABSORBED BY A LARGER EXTRATROPICAL LOW
REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 38.7N 62.4W
NEXT ADVISORY AT 17/0300Z
$$
FORECASTER BERG
|
Hurricane Gert Forecast Discussion Number 16
|
Issued at 500 PM AST Wed Aug 16 2017
000
WTNT43 KNHC 162033
TCDAT3
Hurricane Gert Discussion Number 16
NWS National Hurricane Center Miami FL AL082017
500 PM AST Wed Aug 16 2017
Cloud tops with temperatures colder than -65 deg C have wrapped
almost entirely around Gert's center, although eye temperatures
have been fluctuating all day. Dvorak intensity estimates vary
widely, from T4.5 from TAFB to around T5.5 from the UW-CIMSS ADT,
and since a warm eye has been unable to persist for an extended
period of time, the initial intensity is raised conservatively to
85 kt. This makes Gert the first category 2 hurricane of the
season. The window of opportunity for additional strengthening
appears to be closing. Gert will be moving over the colder waters
north of the Gulf Stream in about 12-18 hours, and southwesterly
shear will be increasing to well over 30 kt in about 12 hours.
Therefore, a fast weakening trend is forecast to begin on Thursday,
with Gert becoming a tropical storm by 36 hours. The FSU
phase-space diagrams indicate that Gert should be extratropical
just after 36 hours, and the GFS, ECMWF, and UKMET all have the
cyclone being absorbed by a larger extratropical low over the north
Atlantic by day 4.
Acceleration continues with the initial motion now 055/27 kt. With
Gert firmly embedded within the mid-latitude westerlies, the
hurricane's forward speed should increase for the next 24 hours,
followed by some deceleration as the cyclone begins to interact
with a large cut-off low moving east of Atlantic Canada. Most of
the track guidance is a little faster on this cycle, although the
ECMWF is significantly slower. The new NHC forecast is nudged a
little faster from 12-48 hours, but not too fast given the latest
ECMWF solution. The post-tropical portion of the track, intensity,
and wind radii forecasts incorporate guidance from NOAA's Ocean
Prediction Center.
Swells from Gert are affecting portions of the mid-Atlantic coast of
the United States, and are expected to spread northward to New
England and Atlantic Canada during the next day or two. These
swells are likely to produce dangerous surf and rip current
conditions. Please consult products from your local weather forecast
office for more information.
FORECAST POSITIONS AND MAX WINDS
INIT 16/2100Z 38.7N 62.4W 85 KT 100 MPH
12H 17/0600Z 40.7N 56.9W 85 KT 100 MPH
24H 17/1800Z 44.3N 48.2W 70 KT 80 MPH
36H 18/0600Z 48.3N 40.4W 55 KT 65 MPH
48H 18/1800Z 51.6N 35.7W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 19/1800Z 54.3N 32.6W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 20/1800Z...ABSORBED BY A LARGER EXTRATROPICAL LOW
$$
Forecaster Berg
|
Hurricane Gert Wind Speed Probabilities Number 16
|
Issued at 2100 UTC WED AUG 16 2017
000
FONT13 KNHC 162033
PWSAT3
HURRICANE GERT WIND SPEED PROBABILITIES NUMBER 16
NWS NATIONAL HURRICANE CENTER MIAMI FL AL082017
2100 UTC WED AUG 16 2017
AT 2100Z THE CENTER OF HURRICANE GERT WAS LOCATED NEAR LATITUDE 38.7
NORTH...LONGITUDE 62.4 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 85 KTS
...100 MPH...155 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 WED 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 WED 06Z THU 18Z THU 06Z FRI 18Z FRI 18Z SAT 18Z SUN
PERIODS TO TO TO TO TO TO TO
06Z THU 18Z THU 06Z FRI 18Z FRI 18Z SAT 18Z SUN 18Z MON
FORECAST HOUR (12) (24) (36) (48) (72) (96) (120)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
LOCATION KT
HIBERNIA OILFD 34 X 3( 3) 2( 5) X( 5) X( 5) X( 5) X( 5)
$$
FORECASTER BERG
|
Hurricane Gert Graphics
|
5-Day Uncertainty Track last updated Wed, 16 Aug 2017 20:38:32 GMT
Wind Speed Probabilities last updated Wed, 16 Aug 2017 21:24:27 GMT |
|