Scattered Flooding Possible Throughout The Region Due To Stalled Frontal Boundary Update Three

Record Setting Category Five Hurricane Irma Takes Aim At Florida

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WTNT41 KNHC 072059
TCDAT1

Hurricane Irma Discussion Number  35
NWS National Hurricane Center Miami FL       AL112017
500 PM EDT Thu Sep 07 2017

Hurricane Irma continues to have an impressive satellite
presentation with a very distinct eye. There is not much more to add
about the current intensity except that numerous data from the Air
Force reconnaissance plane indicate that the winds remain at 150
kt.

The environment along the future track of Irma is favorable for the
hurricane to maintain most of its current intensity, although some
fluctuations are likely due to eyewall replacement cycles which are
difficult to predict. There are no obvious reasons why Irma should
not remain a powerful major hurricane for the next 3 days while it
is heading for Florida or its adjacent surroundings. Thereafter, an
increase in the wind shear and the interaction with land should lead
to gradual weakening.

The best estimate of the initial motion is toward the west-northwest
or 285 degrees at 14 kt. Irma is being steered by the flow around
the south side of the subtropical ridge, but in 2 or 3 days the
hurricane is expected to be located on the southwestern edge of the
aforementioned ridge, and a turn to the northwest and north-
northwest should then begin. The forecast track for the first 2 days
was adjusted a little bit to the south given that the ridge to the
north continues to be strong, and the ECMWF and HFIP corrected
consensus (HCCA) models have shifted southward a little bit. These
two models have been performing very well during Irma.  This
adjustment also results in a westward shift of the track near
Florida and northward.


KEY MESSAGES:

1. Irma is a potentially catastrophic category 5 hurricane and will
continue to bring life-threatening wind, storm surge, and rainfall
hazards to the northern coast of Hispaniola tonight. These hazards
are already spreading across the Turks and Caicos and will affect
the Bahamas tonight through Saturday. Hurricane conditions will also
spread over portions of the north coast of Cuba, especially over
the adjacent Cuban Keys through Saturday.

2. It has become more likely that Irma will make landfall in
southern Florida as a dangerous major hurricane, and bring
life-threatening storm surge and wind impacts to much of the state.
A Hurricane Watch is in effect for South Florida, the Florida Keys,
Lake Okeechobee, and Florida Bay, and will likely be expanded
northward tonight.

3. A Storm Surge Watch is in effect for portions of South Florida
and the Florida Keys. This means there is the possibility of
life-threatening inundation from rising water moving inland from the
coastline during the next 48 hours in these areas. The Potential
Storm Surge Flooding Map depicts a reasonable worst-case scenario -
the amount of inundation that has a 10 percent chance of being
exceeded. Because the Flooding Map is based on inputs that extend
through 72 hours, it best represents the flooding potential in the
watch area.

4. There is a chance of direct impacts in portions of Georgia,
South Carolina, and North Carolina, but it is too early to specify
the magnitude and location of these impacts.

FORECAST POSITIONS AND MAX WINDS

INIT  07/2100Z 20.9N  71.1W  150 KT 175 MPH
 12H  08/0600Z 21.6N  73.1W  145 KT 165 MPH
 24H  08/1800Z 22.2N  75.5W  140 KT 160 MPH
 36H  09/0600Z 22.7N  77.6W  135 KT 155 MPH
 48H  09/1800Z 23.4N  79.3W  135 KT 155 MPH
 72H  10/1800Z 26.2N  80.7W  115 KT 130 MPH...INLAND
 96H  11/1800Z 31.5N  82.0W   80 KT  90 MPH...INLAND
120H  12/1800Z 36.0N  84.0W   40 KT  45 MPH...INLAND

$$
Forecaster Avila

Scattered Flooding Possible Throughout The Region Due To Stalled Frontal Boundary Update Two

12:12 PM ADT Thursday 07 September 2017
Rainfall warning in effect for:

Moncton and Southeast New Brunswick
Rain, at times heavy, is expected.

Significant rainfall has already occurred over the region since Wednesday afternoon. A further 10 mm of rain is possible before tapering to showers early this afternoon. The rain may be very heavy at times giving poor driving conditions.

Heavy downpours can cause flash floods and water pooling on roads. If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop.

Rainfall warnings are issued when significant rainfall is expected.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to ec.weatheraspc.ec@canada.ca or tweet reports using #NBStorm.

10:52 AM ADT Thursday 07 September 2017
Special weather statement in effect for:

Pictou County
A developing low pressure system over Maine will intensify as it tracks northeastward to lie over central Labrador tonight.

Showers and thunderstorms associated with this system are expected to intensify over southwestern Nova Scotia this morning and spread eastward.

At this time 20 to 40 mm of rain is expected with the heaviest amounts possibly exceeding 50 mm by Friday morning however, there remains some uncertainty with the intensity and track of this system. Changes in the forecast track of this feature could significantly alter total rainfall accumulation. Rainfall warnings are currently in effect for the Halifax and eastern shore areas of Nova Scotia where 50 to 70 millimetres are forecast.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to ec.weatheraspc.ec@canada.ca or tweet reports using #NSStorm.

10:51 AM ADT Thursday 07 September 2017
Rainfall warning in effect for:

Halifax Metro and Halifax County West
Rain, at times heavy, is expected.

A developing low pressure system over Maine will intensify as it tracks over northern New Brunswick this afternoon then track to lie over Labrador tonight. Rain associated with this low could give amounts of 50 to 70 millimetres with locally higher amounts possible. Rain is expected to taper to a few showers this evening.

Heavy downpours can cause flash floods and water pooling on roads. If visibility is reduced while driving, turn on your lights and maintain a safe following distance.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to ec.weatheraspc.ec@canada.ca or tweet reports using #NSStorm.