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HURRICANE GERT
08-16-2017, 06:45 AM
Post: #31
RE: HURRICANE GERT
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08-16-2017, 08:40 AM
Post: #32
RE: HURRICANE GERT
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08-16-2017, 03:12 PM (This post was last modified: 08-16-2017 03:14 PM by Her-icane.)
Post: #33
RE: HURRICANE GERT
JM

Quote: [Image: gert-aug16.jpg]

One Hurricane and 3 Tropical Waves to Watch in the Atlantic
Dr. Jeff Masters · August 16, 2017, 15:49



Above: Hurricane Gert as seen by the GOES-16 satellite at 10:45 am EDT August 16, 2017. At the time, Gert was a Category 1 storm with 90 mph winds. Image credit: NOAA/CIRA/RAMMB. NOAA’s GOES-16 satellite has not been declared operational and its data are preliminary and undergoing testing.


We’ve entered the last half of August, when the busiest portion of the Atlantic hurricane season begins. Befitting this time of year, there is plenty of action in the Atlantic today. We have one hurricane, and three African waves that various models predict could develop into tropical cyclones. None of these systems raise alarm bells for me as having the potential to cause serious destruction, but this is the time of year when unexpected development often occurs, and we should watch all of these threat areas with vigilance. One factor that may interfere with development of this week’s storms is the presence of a parade of three tropical upper tropospheric troughs (TUTTs) across the Atlantic (Figure 1.) TUTTs often interfere with tropical cyclone development by bringing dry air and high wind shear.


[Image: tutts-aug16.png]Figure 1. Three tropical upper tropospheric troughs (TUTTs) are positioned just north of Invests 91L, 92L, and a new eastern-Atlantic wave. The sequence of troughs can be seen in orange and green, stretching from the Cape Verde Islands to the Bahamas, in this depiction of low-level atmospheric vorticity, or spin, between the layers of 850 and 925 mb, or between about 0.5 and 1 mile above the ocean surface. This 24-hour forecast depiction is for 2 am EDT Thursday, August 17. TUTTs often interfere with tropical cyclone development by bringing dry air and high wind shear. Image credit: Michael Ventrice/The Weather Company.


Gert becomes the strongest Atlantic hurricane so far in 2017


Hurricane Gert has become the strongest hurricane of this young 2017 Atlantic hurricane season, intensifying to a Category 1 storm with 90 mph winds at 11 am EDT Wednesday. The other Atlantic hurricane of 2017, Hurricane Franklin, peaked out at 85 mph winds shortly before it made landfall on the Mexican Gulf Coast on August 10.


Satellite images on Wednesday morning showed that Gert had a solid ring of heavy thunderstorms surrounding a prominent eye, despite moderate wind shear of about 15 knots and an environment of dry air with a relative humidity at mid-levels of the atmosphere near 45%. Sea surface temperatures of 27.5°C (81°F) were just warm enough to allow continued strengthening.


Forecast for Gert


Gert has only a few hours remaining over the warm waters of the Gulf Stream, in a region where wind shear is low enough to permit continued intensification. The 12Z Wednesday SHIPS model predicted that wind shear over Gert would increase dramatically to the high range, 25 - 30 knots, on Wednesday night, and that Gert would cross into a region with sea surface temperatures (SSTs) below 24°C (75°F) on Thursday morning. These conditions should put the brakes on further intensification by Thursday morning. Our top dynamical intensity models, the HWRF, COAMPS-TC, and the new HMON model (the replacement for the old GFDL model), all predicted in their 6Z Wednesday runs that Gert would peak as a major Category 3 hurricane by Wednesday night or early Thursday morning. Our best statistical intensity models, the DSHIPS and LGEM, were more restrained, predicting that Gert would peak with 90 – 95 mph winds on Wednesday night. The official NHC forecast follows the less aggressive statistical intensity forecast models, with the 11 am EDT Wednesday NHC advisory calling for Gert to peak as a Category 2 hurricane with 100 mph winds on Wednesday night. Gert should transition to a hurricane-strength extratropical storm by Friday. The models are in excellent agreement in a track arcing to the northeast, taking Gert out to sea well south of the Canadian Maritime Provinces.
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08-16-2017, 04:37 PM
Post: #34
RE: HURRICANE GERT
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
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08-17-2017, 02:55 PM (This post was last modified: 08-17-2017 02:56 PM by Her-icane.)
Post: #35
RE: HURRICANE GERT
Henson for JM



Quote:Deep Atlantic Tropics Are Bubbling: Three Systems to Watch Bob Henson · August 17, 2017, 15:32


[Image: gert-ir-1515Z-8.17.17.jpg]
Figure 4. Hurricane Gert’s asymmetric structure is evident in this enhanced infrared satellite image from 1515Z (11:15 am EDT) Thursday, August 17, 2017. Image credit: NOAA/NESDIS.


Hurricane Gert tops out at Category 2 strength

Hurricane Gert became the Atlantic’s strongest hurricane of the year on Wednesday, hitting Category 2 strength while scooting across the open northwest Atlantic. Gert intensified further overnight, packing top sustained winds of 90 knots (105 mph) at 11 pm EDT Wednesday, but strengthening wind shear and cooler waters began taking their toll on Thursday morning. Gert was again a Category 1 storm as of 11 am Thursday, with top sustained winds of 70 knots (80 mph). Located about 700 miles east of Halifax, Nova Scotia, and racing east-northeast at about 40 mph, Gert was rapidly evolving into a midlatitude (extratropical) storm, and it will likely be classified as post-tropical by Thursday night.
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