Hurricane Isaias Downgraded To A Tropical Storm As It Races Northward

Isaias Local Watch/Warning Statement/Advisory Number 30

National Weather Service Gray ME  AL092020

1105 AM EDT Tue Aug 4 2020

MEZ008-042315-

/O.CON.KGYX.TR.W.1009.000000T0000Z-000000T0000Z/

Northern Franklin-

1105 AM EDT Tue Aug 4 2020

...TROPICAL STORM WARNING REMAINS IN EFFECT...

* LOCATIONS AFFECTED

    - Carrabassett Valley

* WIND

    - LATEST LOCAL FORECAST: Equivalent tropical storm force wind

        - Peak Wind Forecast: 20-30 mph with gusts to 50 mph

    - THREAT TO LIFE AND PROPERTY THAT INCLUDES TYPICAL FORECAST

      UNCERTAINTY IN TRACK, SIZE AND INTENSITY: Potential for wind 39

      to 57 mph

        - The wind threat has remained nearly steady from the

          previous assessment.

        - PLAN: Plan for hazardous wind of equivalent tropical storm

          force.

        - PREPARE: Remaining efforts to protect property should be

          completed as soon as possible. Prepare for limited wind

          damage.

        - ACT: Move to safe shelter before the wind becomes hazardous.

    - POTENTIAL IMPACTS: Limited

        - Damage to porches, awnings, carports, sheds, and unanchored

          mobile homes. Unsecured lightweight objects blown about.

        - Many large tree limbs broken off. A few trees snapped or

          uprooted, leading to downed power lines.

        - A few roads impassable from debris, caused by downed

          branches and power lines. Hazardous driving conditions on

          bridges and other elevated roadways.

        - Scattered power and communications outages likely.

* FLOODING RAIN

    - LATEST LOCAL FORECAST: Flash Flood Watch is in effect

        - Peak Rainfall Amounts: Additional around 1 inch

    - THREAT TO LIFE AND PROPERTY THAT INCLUDES TYPICAL FORECAST

      UNCERTAINTY IN TRACK, SIZE AND INTENSITY: Potential for

      moderate flooding rain

        - The flooding rain threat has remained nearly steady from

          the previous assessment.

        - PLAN: Emergency plans should include the potential for

          moderate flooding from heavy rain. Evacuations and rescues

          are possible.

        - PREPARE: Consider protective actions if you are in an area

          vulnerable to flooding.

        - ACT: Heed any flood watches and warnings. Failure to take

          action may result in serious injury or loss of life.

    - POTENTIAL IMPACTS: Significant

        - Moderate rainfall flooding may prompt several evacuations

          and rescues.

        - Rivers and tributaries may quickly become swollen with

          swifter currents and overspill their banks in a few places,

          especially in usually vulnerable spots. Small streams,

          creeks, canals, and ditches will overflow.

        - Flood waters can enter some structures or weaken

          foundations. Several places may experience expanded areas

          of rapid inundation at underpasses, low-lying spots, and

          poor drainage areas. Some streets and parking lots take on

          moving water as storm drains and retention ponds overflow.

          Driving conditions will become hazardous. Some road and

          bridge closures.

* TORNADO

    - LATEST LOCAL FORECAST:

        - Situation is somewhat favorable for tornadoes

    - THREAT TO LIFE AND PROPERTY THAT INCLUDES TYPICAL FORECAST

      UNCERTAINTY IN TRACK, SIZE AND INTENSITY: Potential for a few

      tornadoes

        - The tornado threat has remained nearly steady from the

          previous assessment.

        - PLAN: Emergency plans should include the potential for a

          few tornadoes.

        - PREPARE: If your shelter is particularly vulnerable to

          tornadoes, prepare to relocate to safe shelter before

          hazardous weather arrives.

        - ACT: If a tornado warning is issued, be ready to shelter

          quickly.

    - POTENTIAL IMPACTS: Limited

        - The occurrence of isolated tornadoes can hinder the

          execution of emergency plans during tropical events.

        - A few places may experience tornado damage, along with

          power and communications disruptions.

        - Locations could realize roofs peeled off buildings,

          chimneys toppled, mobile homes pushed off foundations or

          overturned, large tree tops and branches snapped off,

          shallow-rooted trees knocked over, moving vehicles blown

          off roads, and small boats pulled from moorings.

* FOR MORE INFORMATION:

    - http://ready.gov/hurricanes

$$

430 

WTNT44 KNHC 041459

TCDAT4

Tropical Storm Isaias Discussion Number  30

NWS National Hurricane Center Miami FL       AL092020

1100 AM EDT Tue Aug 04 2020

Doppler radar data from Dover, Delaware (KDOX), and Ft. Dix, New 

Jersey (KDIX) this morning continue to indicate 70-80 kt winds 

between 4000-7000 ft over the ocean just offshore the Delmarva 

peninsula and the southeastern coast of New Jersey, which would 

normally correspond to 65-70 kt surface winds. However, these 

velocity values have been collocated with only 15-25 dBZ 

reflectivity echoes, so the typical 80-85 percent reduction factors 

likely don't apply. Sustained observed surface winds of 50-55 kt 

have been reported, so the initial intensity will be held at 60 kt, 

but that is only for winds over the ocean and near the coast.

Isaias is moving north-northeastward or 020/30 kt. The cyclone will 

continue to accelerate north-northeastward today and tonight within 

strong southwesterly flow ahead of a deep-layer trough and 

associated cold front approaching the mid-Atlantic and New England 

areas from the west. By 24 h, the Isaias is expected to slow down 

and degenerate into a post-tropical cyclone over Maine before it is 

absorbed by a larger extratropical low located over southeastern 

Canada.  The new NHC track forecast is just an extension of the 

previous advisory, and lies very close to the tightly clustered 

consensus track models.

As Isaias moves north-northeastward through the Mid-Atlantic coast,

interaction with a strong upper-level jet maximum is forecast to

maintain the tropical storm's intensity longer than what typically 

would be expected for inland decaying tropical cyclone. The global 

models continue to indicate that Isaias is likely to produce 

widespread tropical-storm conditions, with hurricane-force wind 

gusts possible along the mid-Atlantic coast through this afternoon. 

As a result, the gust factor at 12 h remains above the  standard 

20-percent value in the Forecast/Advisory Product (TCMAT4).

In addition to the wind threat, Isaias is expected to produce heavy 

rainfall along and just west of the I-95 corridor today, and the 

Weather Prediction Center has placed a portion of this area in a 

high risk for life-threatening flash flooding.

There also remains a significant risk of tornadoes across the 

mid-Atlantic coast and southeastern New York this afternoon, 

possibly spreading into southern New England tonight.

Key Messages:

1. Widespread sustained tropical storm force winds and gusts to 

hurricane force are expected along the mid-Atlantic coast, including 

portions of the Chesapeake Bay region, through this afternoon, which 

could cause tree damage and power outages. Tropical storm conditions 

are expected to spread across New England tonight.

2.  Heavy rainfall along the East Coast, near the path of Isaias, 

will result in flash flooding, some of which may be significant in 

the mid-Atlantic and Northeast through tonight. Potentially 

life-threatening urban flooding remains possible in Philadelphia 

and elsewhere along and just west of the I-95 corridor today. 

Scattered minor to moderate river flooding is likely across portions 

of the and the Mid-Atlantic. Quick-responding rivers in Northeast 

will also be susceptible to minor river flooding. 

3.  Numerous tornadoes have already occurred over portions of the 

mid-Atlantic coast this morning. The threat of tornadoes will 

continue along the mid-Atlantic coast spread into New England this 

afternoon.

FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 39.1N  76.1W   60 KT  70 MPH...INLAND

 12H  05/0000Z 43.2N  73.8W   50 KT  60 MPH...INLAND

 24H  05/1200Z 48.2N  71.7W   35 KT  40 MPH...POST-TROP/INLAND

 36H  06/0000Z 52.0N  71.1W   30 KT  35 MPH...POST-TROP/EXTRATROP

 48H  06/1200Z 53.6N  69.5W   20 KT  25 MPH...POST-TROP/EXTRATROP

 60H  07/0000Z...DISSIPATED INLAND

$$

Forecaster Stewart

8:36 AM ADT Tuesday 04 August 2020

Tropical cyclone information statement for:

New Brunswick

Québec - south:

Amqui - Matapédia Valley

Beauce

Charlevoix

Eastern Townships

Forillon National Park - Gaspé - Percé

Gaspésie National Park - Murdochville

Kamouraska - Rivière-du-Loup - Trois-Pistoles

Matane

Montmagny - L'Islet

New Carlisle - Chandler

Québec

Restigouche - Bonaventure

Rimouski - Mont-Joli

Sainte-Anne-des-Monts - Grande-Vallée

Témiscouata

For Tropical Storm Isaias.

The next information statement will be issued by 2:00 p.m. EDT today.

1. Summary of basic information at 8:00 a.m. EDT.

Location: 37.7 North 76.8 West.

About 54 kilometres east-northeast of Richmond, VA.

Maximum sustained winds: 100 kilometres per hour.

Present movement: north-northeast at 46 kilometres per hour.

Minimum central pressure: 994 millibars.

2. Public weather impacts and warnings summary.

The Canadian Hurricane Centre is closely monitoring the progress of Tropical Storm Isaias (pronounced ees-ah-EE-ahs). Isaias will approach Quebec and New Brunswick through New England tonight. The expected impacts for Canada are heavy rainfall in southern and eastern parts of Quebec and moderate gusty winds including New Brunswick.

a. Wind.

Southeasterly winds gusting to 50 km/h are likely over New Brunswick and parts of Quebec including eastern Townships and areas along the St. Lawrence River tonight. As the low moves northward through Quebec Wednesday expect warm and humid southerly winds across the region. New Brunswick and the Gaspe region could see gusts up to 70 km/h Wednesday afternoon.

b. Rainfall.

A brief period of heavy rain from the direct remnants of the storm is expected over parts of southern Quebec after midnight tonight into early tomorrow morning. The eastern Townships northward to the Quebec City area is most likely to be affected with up to 60 mm. Most of the rain will fall over a short period of time (2-3 hours) therefore some minor flooding may occur in prone locations.

Additional note on rainfall as of Tuesday morning: Showers well ahead and to the west of the storm track throughout today are not directly related to Isaias. Also note that heavy rainfall may occur further west into the Montreal area as well due to a combination of Isaias' remnants and a non-tropical low farther west.

c. Surge/Waves.

Nothing significant expected. Waves of 2-3 m along the southwestern portion of New Brunswick are expected tonight and into Wednesday.

3. Marine weather impacts and warnings summary.

Marginal gale-force winds can be expected over westernmost Maritime marine regions including the mouth of the St. Lawrence River tonight and into Wednesday. Seas of 2-3 metres are expected. Small craft operators should take precautions.

Forecasters: Fogarty/Spencer/Hatt

Please continue to monitor alerts issued by the Canadian Hurricane Centre and forecasts issued by Environment Canada.

Isaias Local Watch/Warning Statement/Advisory Number 29

National Weather Service Caribou ME  AL092020

537 AM EDT Tue Aug 4 2020

MEZ030-041745-

/O.CON.KCAR.TR.W.1009.000000T0000Z-000000T0000Z/

Coastal Washington-

537 AM EDT Tue Aug 4 2020

...TROPICAL STORM WARNING REMAINS IN EFFECT...

* LOCATIONS AFFECTED

    - Eastport

    - Machias

    - Cherryfield

* WIND

    - LATEST LOCAL FORECAST: Tropical storm force wind

        - Peak Wind Forecast: 25-35 mph with gusts to 50 mph

    - THREAT TO LIFE AND PROPERTY THAT INCLUDES TYPICAL FORECAST

      UNCERTAINTY IN TRACK, SIZE AND INTENSITY: Potential for wind 39

      to 57 mph

        - The wind threat has remained nearly steady from the

          previous assessment.

        - PLAN: Plan for hazardous wind of equivalent tropical storm

          force.

        - PREPARE: Remaining efforts to protect property should be

          completed as soon as possible. Prepare for limited wind

          damage.

        - ACT: Move to safe shelter before the wind becomes hazardous.

    - POTENTIAL IMPACTS: Limited

        - Damage to porches, awnings, carports, sheds, and unanchored

          mobile homes. Unsecured lightweight objects blown about.

        - Many large tree limbs broken off. A few trees snapped or

          uprooted, but with greater numbers in places where trees

          are shallow rooted. Some fences and roadway signs blown

          over.

        - A few roads impassable from debris, particularly within

          urban or heavily wooded places. Hazardous driving

          conditions on bridges and other elevated roadways.

        - Scattered power and communications outages.

* STORM SURGE

    - No storm surge inundation forecast

    - THREAT TO LIFE AND PROPERTY THAT INCLUDES TYPICAL FORECAST

      UNCERTAINTY IN TRACK, SIZE AND INTENSITY: Little to no storm

      surge flooding

        - The storm surge threat has remained nearly steady from the

          previous assessment.

        - PLAN: There is little to no threat of storm surge flooding.

          Rough surf, coastal erosion, and life-threatening rip

          currents are possible.

        - PREPARE: Little to no preparations for storm surge flooding

          are needed.

        - ACT: Follow the instructions of local officials. Monitor

          forecasts.

    - POTENTIAL IMPACTS: Little to None

        - Little to no potential impacts from storm surge flooding.

* FLOODING RAIN

    - LATEST LOCAL FORECAST:

        - Peak Rainfall Amounts: Up to 1 inch

    - THREAT TO LIFE AND PROPERTY THAT INCLUDES TYPICAL FORECAST

      UNCERTAINTY IN TRACK, SIZE AND INTENSITY: Little or no

      potential for flooding rain

        - The flooding rain threat has remained nearly steady from

          the previous assessment.

        - PLAN: There is little or no potential for flooding rain.

        - PREPARE: Little to no preparations are needed to protect

          against flooding rain at this time.

        - ACT: Monitor for changes to the forecast.

    - POTENTIAL IMPACTS: Little to None

        - Little to no potential impacts from flooding rain.

* TORNADO

    - LATEST LOCAL FORECAST:

        - Situation is somewhat favorable for tornadoes

    - THREAT TO LIFE AND PROPERTY THAT INCLUDES TYPICAL FORECAST

      UNCERTAINTY IN TRACK, SIZE AND INTENSITY: Potential for a few

      tornadoes

        - The tornado threat has increased from the previous

          assessment.

        - PLAN: Emergency plans should include the potential for a

          few tornadoes.

        - PREPARE: If your shelter is particularly vulnerable to

          tornadoes, prepare to relocate to safe shelter before

          hazardous weather arrives.

        - ACT: If a tornado warning is issued, be ready to shelter

          quickly.

    - POTENTIAL IMPACTS: Limited

        - The occurrence of isolated tornadoes can hinder the

          execution of emergency plans during tropical events.

        - A few places may experience tornado damage, along with

          power and communications disruptions.

        - Locations could realize roofs peeled off buildings,

          chimneys toppled, mobile homes pushed off foundations or

          overturned, large tree tops and branches snapped off,

          shallow-rooted trees knocked over, moving vehicles blown

          off roads, and boats pulled from moorings.

* FOR MORE INFORMATION:

    - http://maine.gov/mema/weather/hurricane.shtml

$$

Hewitt