Tuesday August 4, 2020
Tropical Storm Isaias

Hurricane Center Isaias Track Plot
Hurricane and Tropical Storm Force Wind Swath Along the Path

National Hurricane Center Wind Field Track for Isaias

Isaias had a troubled tropical lifecycle struggling against dry air and hostile upper level winds at times on its trek across the islands of the Caribbean and the Bahamas, toggling back and forth between tropical storm and category 1 hurricane status as it approached the Florida coastline. The storm made an anticipated sharp right turn before reaching Florida due to strong southwest steering flow which was generated over the Southeast by a deep mid latitude jet stream trough that had dug south through the east central part of the country. Upper level wind conditions briefly became favorable to vent the storm, rather than shear it, as it approached the north Carolina coast on August 3, which allowed the Isaias to better organize while over the very warm gulf stream waters and briefly intensify into an 85 mph Hurricane prior to making landfall. From North Carolina, Isaias accelerated up the coast, tracking inland through the mid Atlantic states, to near Albany around 5pm on August 4, then into Canada prior to midnight as a tropical storm.

The storm maintained a good amount of punch on its arrival in the Northeast, despite tracking over land, due to its interaction with the strong upper level trough which maintained favorable venting of the system allowing to maintain a strong circulation and ability to generate torrential tropical rain and strong wind gusts all the way into New York. The storm's rapid forward motion, 40-45 mph, also aided in bringing a stronger storm into the Northeast vs. had it been moving slower which would have allowed it to spin down to a greater extent prior to a Northeast arrival.

Torrential rain occurred locally along and west of the track, impacting the Hudson valley and points west. A brief period of strong gusty wind also occurred and was maximized for a short period as the heavy rain was ending during the late afternoon and early evening. Further east into New England, rainfall was comparatively light, but the period of strong wind gusts resulted in widespread damage to trees and power lines with Connecticut particularly hard hit with 861,000 customers losing power (a top 5 power outage event for the state) with major outages lasting over week. Through the duration of the storm as it moved up from the Carolinas into the Northeast power went out for millions with an estimated 6.4 million utility customers affected with 3.8 million out of power at one time. On top of the major power outages in Connecticut, It's estimated that 1.65 million lost power in New Jersey, 1.19 million in New York (about 90,000-100,000 in the WRGB County coverage area with Dutchess County hardest hit with 66,000 reported outages on the 5th.) Further, 570,000 lost power in Pennsylvania, 520,000 in Virginia, 495,000 in North Carolina and 1.12 million in other states. (Power outage statistics provided by PowerOutage.US)

The following four Satellite/Radar composite images illustrate the positions of Isaias as it tracked up the coast and through the heart of the Capital Region on Tuesday August 4, 2020

11am Tuesday August 4, 2020

11am Tuesday August 4, 2020 - Satellite/Radar Composite Image

2pm Tuesday August 4, 2020

2pm Tuesday August 4, 2020 - Satellite/Radar Composite Image

5pm Tuesday August 4, 2020

5pm Tuesday August 4, 2020 - Satellite/Radar Composite Image

8pm Tuesday August 4, 2020

8pm Tuesday August 4, 2020 - Satellite/Radar Composite Image 

Local Time Line

Midnight to Noon Tuesday August 4
Rain broke out across the region, mainly in the form of showers, well in advance of the arrival of the storm with a cluster of downpours and t'storms moving up through parts of the mid Hudson valley into the Berkshires shortly after midnight. Initial rainfall, however, through the pre-dawn hours, was scattered and light. Rainfall, did, however, become more concentrated and steadier in areas from the Hudson valley on west after 6-8am with areas of tropical downpours embedded within the rain shield as well as over the Capital Region and Hudson valley area. It is arguable that this area of lead rain was part of a pseudo predecessor (PRE) event created by strong jet stream divergence aloft interacting with the tropical moisture plume coming up in advance of Isaias. Missing, however, was a strong surface boundary, separating a cooler, drier air mass from incoming tropical air mass, for the moisture to overrun. Had a less homogeneous air mass been in place over the region, rainfall would have been heavier in the PRE as well as during the period when the core of the storm moved through.

Rainfall steadily increased along and west of the Hudson valley with more of a showery tropical downpour scenario in the Hudson valley and across western New England, the part of our area on the eastern side of the circulation. A high shear and somewhat unstable environment existed in this region, favorable for transient brief tornado spin-ups, in a tropical storm that had a history of spawning numerous tornadoes across the Carolinas and mid Atlantic the previous night. A tornado watch was issued by the Storm Prediction Center from essentially the Hudson valley area on east at 12:45pm as an alert for this potential. The watch was initially issued with a 9pm expiration, but was cancelled around 5pm as the tornado threat had passed by that time. There were two tornado warned cells locally, one that impacted northern Columbia and SW Rensselaer counties, the other for Windham and Bennington counties in Vermont. No tornado touchdowns were confirmed, although radar indicated strong rotation aloft in both warned downpour cells.

Tornado watch area Tuesday August 4, 2020 valid from 12:45pm to 5pm

The core of the storm impacted the region roughly from 2pm through 7pm with torrential tropical rains concentrated along and west of the storm's track which was along and immediately west of the Hudson river. 1"-2" per hour rainfall rates were common with a widespread blinding rain over the Capital Region from 3-6pm, a period where two to three inches of rain fell resulting in widespread flash flooding with many flooded streets and basements. Flash flooding was also widespread in the Catskills where anywhere from 4"-7" of rain fell with the higher totals closer to 7" falling in terrain favored areas of Greene and Ulster counties.

2pm NHC Isaias track path forecast Tuesday August 4, 2020

With the fast forward speed of the storm, rain quickly shut down from SW to NE across the region from the late afternoon through the evening with significant rain out of all areas between 7 and 8pm. A swath of 3"-5" rains stretched from northern Washington and Warren counties, south through the Saratoga-Capital Region, eastern Mohawk valley, Schoharie County, and Catskills. Rainfall generally ranged from 1"-2" in the mid Hudson valley with up to 3" in terrain favored areas in southern Vermont. No river flooding occurred anywhere in the local area as rivers and streams were running very low in advance of the storm due to prolonged antecedent dry conditions. The eastern half of the local area, according to the Northeast Drought monitor prior to the storm, was the driest part of the region. This was also the part of the region that got the least amount of rainfall.

Albany National Weather Service Rainfall Amount and Distribution Analysis, August 4, 2020 - Tropical Storm Isaias

Albany NWS Rainfall Analysis for Tropical Storm Isaias

3.92" of rain fell at Albany (airport location) setting a 24 hour rainfall record for the date. This, to date, is also the 4th heaviest single day rainfall on record at Albany.

Albany, NY Rainfall Record for August 4, 2020

Highlight List of CBS6 WeatherNet 6 spotter rainfall reports for August 4, 2020

Select WeatherNet 6 Rainfall Reports - August 4, 2020 


WeatherNet 6 Storm Total Rainfall Reports for August 4, 2020
(NYSM = New York State Mesonet Observation)
(CBS6 = Freihofer's Weather Station Observation)

Town County Rainfall Report Town County Rainfall Report
Hancock, MA Berkshire 1.66" Pittsfield, MA Berkshire 1.31"
Great Barrington, MA Berkshire 1.47" Becket, MA Berkshire 1.63"
Pittsfield, MA Berkshire 1.31" Clarksburg, MA Berkshire 2.85"
Pittsfield, MA (CBS6) Berkshire 1.61"      
Albany (ASOS) Albany 3.92"* Record Albany (Downtown) Albany 4.43"
Albany (Downtown) Albany 5.35" Rensselaerville Albany 3.25"
Glenmont Albany 3.05" to 4.22" Cohoes Albany 3.55"
Colonie Albany 3.50" Delmar Albany 3.00"
South Berne Albany 2.80" Voorheesville (NYSM) Albany 3.46"
Empire State Plaza (CBS6) Albany 2.18"      
Livingston Columbia 1.50" Taghkanic Columbia 1.10"
Germantown Columbia 3.00" Kinderhook (NYSM) Columbia 2.26"
Copake (NYSM) Columbia 2.16"      
Denver Delaware 2.45" Arkville Delaware 5.02"
Roxbury Delaware 3.13" Margaretville Delaware 4.02" to 4.35"
Davenport Delaware 2.85"      
Red Hook Dutchess 1.61" Pine Plains Dutchess 1.25"
Stratford Fulton 4.00" Perth Fulton 1.95"
Broadalbin Fulton 3.50" Oppenheim (NYSM) Fulton 2.59"
South Cairo Greene 3.60" Greenville Greene 3.41"
Halcott Greene 4.42" Cairo Greene 4.15" to 5.00"
Prattsville Greene 5.30" West Kill Greene 3.28"
Catskill Greene 2.36" to 2.69" Haines Falls Greene 5.80"
Tannersville (NYSM) Greene 5.00"      
Indian Lake Hamilton 1.40" Piseco (NYSM) Hamilton 2.62"
Piseco Hamilton 2.50" Indian Lake (NYSM) Hamilton 2.42"
Amsterdam Montgomery 2.08" to 2.37" Fonda Montgomery 2.72"
Glen Montgomery 3.23" Hessville Montgomery 2.38"
Palatine Bridge Montgomery 2.12" Sprakers (NYSM) Montgomery 2.87"
Johnstown (NYSM) Montgomery 2.20" Amsterdam (CBS6) Montgomery 1.90"
Oneonta Otsego 2.70" to 2.92" East Worcester Otsego 3.15"
Worcester Otsego 3.23"      
Castleton Rensselaer 3.14" Center Brunswick Rensselaer 2.15"
Speigletown Rensselaer 4.50" Petersburg Rensselaer 1.46"
Hoosick Falls Rensselaer 1.72" Schaghticoke Rensselaer 3.75"
Stephentown (NYSM) Rensselaer 1.64" Troy (CBS6) Rensselaer 2.21"
Charlton Saratoga 4.30" Galway Saratoga 3.22"
Clifton Park (Oaks) Saratoga 3.40" Saratoga Springs Saratoga 2.53" to 2.90"
Malta Saratoga 3.42" Edinburg Saratoga 2.74"
Wilton Saratoga 3.50" Lake Desolation Saratoga 2.50"
Ballston Spa (NYSM) Saratoga 3.03" Saratoga (Broadway - CBS6) Saratoga 1.09"
Delanson Schenectady 2.76" to 3.50" Schenectady Schenectady 3.38"
Duanesburg Schenectady 5.22" Rotterdam Schenectady 2.92"
East Glenville Schenectady 3.53" Schenectady (State St.- CBS6) Schenectady 2.73"
Huntersland Schoharie 3.47" to 3.67" Conesville Schoharie 4.50"
Richmondville Schoharie 4.13" Jefferson Schoharie 4.75"
Warnerville Schoharie 4.05" Charlotteville Schoharie 3.70"
Schoharie Schoharie 3.50" Middleburgh Schoharie 3.67"
Phoenicia Ulster 7.01" Kingston Ulster 1.95"
Esopus Ulster 1.42" Claryville (NYSM) Ulster 3.03"
Warrensburg Warren 3.55" Queensbury Warren 3.26"
Glens Falls Warren 2.65" to 3.33" Lake Luzerne Warren 2.80"
Chestertown (NYSM) Warren 3.26" Lake George (CBS6) Warren 2.20"
Glens Falls (CBS6) Warren 2.17"      
Hartford Washington 4.01" Hudson Falls Washington 3.71"
Hebron Washington 3.40" Greenwich Washington 3.88"
Granville Washington 3.84" Whitehall (NYSM) Washington 3.25"
Woodford, VT Bennington 2.64" West Arlington, VT Bennington 1.16"
Landgrove, VT Bennington 1.68" Manchester, VT Bennington 2.57"
Danby, VT Rutland 1.85" Wilimington, VT Windham 1.91"

Although the National Hurricane Center maintained Isaias as a 60 mph tropical storm as it moved through the Capital Region, most of that wind was aloft prior to and during the peak of the storm. In fact very light wind conditions were common in most areas through much of the day and especially in the heavy rain areas west of the Hudson valley. However, 30-50 mph gusts did occur in localized bursts during the storm as heavier rain elements mixed down some stronger wind from aloft mainly in areas along and east of the track in the from the Hudson river on east into western New England. A brief period of more widespread strong wind gusts occurred late in the afternoon and during the early evening on the southern and eastern side of the circulation as some of the high momentum air from aloft was mixed down right as the rain was ending and also coincident with developing breaks of sunshine. These gusts, coupled with the very wet ground conditions was more than sufficient to blow down trees and power lines causing numerous power outages.

A wind advisory was in effect for the event with a tropical storm warning for Berkshire and Litchfield counties. Despite no difference in expected wind conditions, tropical storm warnings are mandated by the NWS for Berkshire and Litchfield counties when the rest of Massachusetts and Connecticut are under that alert. This is why there were two different types of advisories for wind posted by the NWS for our region.

Wind Advisory county outline map Tuesday August 4, 2020

Peak Gust Wind Measurements From Across The Region - August 4, 2020
(NYSM = New York State Mesonet Observations)
(CBS6 = Freihofer's Weather Station Observations)

Town County Peak Gust Time of Gust
Pittsfield, MA (ASOS) Berkshire 46 mph 2:56pm
Pittsfield, MA (CBS6) Berkshire 46 mph  
Peru, MA Berkshire 41 mph 12:01pm
Albany (ASOS) Albany 39 mph 4:05pm
Medusa (NYSM) Albany 35 mph 3:30pm
Empire State Plaza (CBS6) Albany 37 mph  
Copake (NYSM) Columbia 50 mph 3:55pm
Beacon (NYSM) Dutchess 51 mph 2:40pm
Dover Plains Dutchess 45 mph 3:15pm
Johnstown (NYSM) Montgomery 40 mph 4:40pm
Amsterdam (CBS6) Montgomery 39 mph  
Stephentown (NYSM) Rensselaer 40 mph 4:55pm
Troy (CBS6) Rensselaer 39 mph  
Saratoga Springs (CBS6) Saratoga 35 mph  
Schenectady (CBS6 - 100') Schenectady 53 mph  
East Glenville Schenectady 36 mph 3:45pm
Lake George (CBS6) Warren 43 mph  
Glens Falls (CBS6) Warren 37 mph  
Bennington, VT Bennington 31 mph 3:08pm
Mount Washington, NH Coos 147 mph Highest August Gust on Record
Mount Mansfield, VT Lamoille 70 mph 10:50pm
Rutland, VT Rutland 40 mph 5:03pm

Wind Damage in Chatham Center - Columbia County - Photograph shot and contributed by WeatherNet 6 Spotter Jim Meehan on Wednesday August 5, 2020

Wind Damage in Chatham Center, Columbia County

Wind damage in South Egremont, MA (Berkshire County) on August 4, 2020: Photograph contributed by WeatherNet 6 spotter Jim Meehan

Wind damage in South Egrement, MA, Berkshire County August 4, 2020

NWS Storm Reports for Tuesday August 4, 2020. Note, these reports are used to verify the NWS warnings/Advisories which were issued for the tropical storm and therefore do not necessarily represent an accounting for all of the wind damage which may have occurred.

Town County Tropical Storm - Flood - Wind Damage Report Time
Wingdale Dutchess Multiple trees blown down 1:35pm
LaGrange Dutchess Multiple large tree limbs down in LaGrange and Uniondale 2:00pm
Ravena Albany Large honey locust tree blown down on a property 2:00pm
2 Miles SSW of Charlton Schenectady Large tree blown down at the intersection of Sacandaga Rd. and Goldfoot Rd. 2:00pm
Hawthorne Hill Schenectady Large tree snapped and falling to the side of the road near Oakmont Terrace and Consaul Road 3:00pm
Millbrook Dutchess Trees and wires blown down 3:00pm
Ballston Spa Saratoga Trees and wires blown down 3:05pm
Winsted, CT Litchfield Trees and live wires down on a house in town 3:06pm
Milton Saratoga Wires blown down on Old Post Road 3:09pm
Torrington, CT Litchfield Trees blown down onto a building on Main Street 3:18pm
Dalton Berkshire Trees blown down 3:25pm
Pittsfield, MA Berkshire Trees blown down 3:25pm
Dorset, VT Bennington Tree an dpower lines down on Mount Aeolus Lane 4:04pm
Niskayuna Schenectady Trees down 4:08pm
Hudson Falls Washington Trees down on Blenor Avenue 4:09pm
Peru, MA Berkshire Downed trees 4:10pm
Hinsdale, MA Berkshire Downed trees 4:12pm
Rotterdam Schenectady FLASH FLOOD: Flooding of the underpass on Curry Road in the area of Cederlawn Avenue 4:15pm
Colonie Albany FLASH FLOOD: Flooding blocking the intersection of Locust Park and Thunder Road in Colonie 4:20pm
Richmond, MA Berkshire Large tree limbs blown down 4:20pm
Delmar Albany FLASH FLOOD: Route 443 E/W at Route 335 in Bethlehem, all lanes closed due to flooding 4:23pm
Niskayuna Schenectady Wires down and arcing on River Road and Van Antwerp Road 4:24pm
Delmar Albany FLASH FLOOD: Flooding at the intersection of Delaware Avenue and Kenwood Avenue 4:26pm
Hollowville Columbia Wind damage: Transformer fire at the power substation near the intersection of Route 23 and County Route 11 4:28pm
Pittsfield, MA Berkshire Large tree blown down 4:30pm
Poughkeepsie Dutchess Large tree branches blown down 4:30pm
Fort Ann Washington Tree and power lines down on Sate Route 149 4:30pm
Delmar Albany FLASH FLOOD: All lanes near Route 335 at Feura Bush Road closed due to flooding 4:32pm
Halfmoon Saratoga Tree blown down onto a home 4:35pm
Westmere Albany FLASH FLOOD: Route 20 closed between Schoolhouse Road and Fuller Road due to flooding. Water depth estimated to be four feet 4:38pm
Dorset, VT Bennington Power lines blown down on Upper Hollow Road 4:42pm
Perth Fulton Trees blown down on Reidel Road 4:42pm
Broadalbin Fulton Wires blown down on Route 155 4:42pm
Wilton Saratoga All lanes closed Near Route 9 and Ballard Road due to downed trees 4:43pm
Niskayuna Schenectady FLASH FLOOD: Flooding on Dean Street and Baker Avenue 4:45pm
Ballston Spa Saratoga Wires blown down on Middleline Road 4:50pm
Dorset, VT Bennington Power lines blown down on Route 30 4:52pm
Westmere Albany Route 20 closed between Schoolhouse Road and Fuller Road due to severe flooding 4:54pm
Saratoga Lake Saratoga Trees and wires blown down on Riley Cove Road 4:55pm
Philmont Columbia Tree down on Rigor Hill Road just west of the Taconic Parkway 4:58pm
Chatham Columbia Multiple trees and utility poles blown down. Damage to the Chatham Middle School Roof 5:05pm
Scotia Schenectady FLASH FLOOD: Route 147 from Swan to Neal Street in Scotia, all lanes closed due to flooding 5:10pm
Nassau Rensselaer All lanes of Route 20 in Nassau closed at Jefferson Hill Road due to downed trees 5:14pm
Fort Ann Washington Trees and power lines down on Hadlock Pond Road 5:14pm
Charlton Saratoga Trees and wires down on Eastern Avenue 5:17pm
Greenwich Washington Tree and power lines down on McClay Road 5:20pm
Dorset, VT Bennington Trees and wires down in Dorset and East Dorset from wind 5:25pm
Albany Albany FLASH FLOOD: Multiple reports of flooded roads in the city and stranded cars 5:30pm
Argyle Washington Power pole fire on Lehret Road 5:51pm
Rockton Montgomery Trees down near Miami Avenue and Midline Road 5:55pm
Amsterdam Montgomery FLASH FLOOD: State Highway 30 south of Amsterdam from Fuller Road to Sate Highway 161 in Florida closed due to flooding 6:00pm
Fort Ann Washington Tree down on power lines on Goodman Road 6:03pm
Mariaville Schenectady FLASH FLOOD: All lanes closed on Route 159 at Route 30 due to flooding 6:05pm
Fort Ann Washington Tree down on power lines on Buttermilk Falls Road 6:09pm
Heuletts Landing Warren Tree blown down on County Route 7 in Dresden 6:13pm
East Glenville Schenectady FLASH FLOOD: Route 50 at Route 914V in Glenville closed due to flooding, all lanes closed 6:16pm
Greenfield Center Saratoga Tree and power lines blown down 6:35pm
Hawthorne Hill Schenectady Tree down blocking River Road 6:38pm
Whitehall Washington Tree blown down on Hutton Square Road in Putnam 6:47pm
Fort Ann Washington Tree and power lines blown down on Lake Nebo Road 6:58pm
New Baltimore Greene Route 144 in New Baltimore closed due to a downed pole and wires 7:00pm
West Sand Lake Rensselaer Route 43 in West Sand Lake closed at Breigle Lane due to a downed tree 7:10pm
Fort Ann Washington Tree blown down on Buttermilk Falls Road 7:38pm
Cambridge Washington Tree and power lines blown down on King Road 7:51pm
Fort Ann Washington Tree and power lines down on Burquist Road 8:17pm