Weekend Outlook: August 7-10, 2020

It won’t be all sunshine and warm temperatures, but we should be able to salvage a decent weekend around here.

The high pressure system providing us with a nice day today will slide off to the east tonight, while a weak low pressure system moves along a frontal boundary that has stalled out to our south. That will send clouds our way tonight and Friday. Some showers and maybe even a thunderstorm are expected on Friday as the front tries to lift northward, but they’ll likely be confined to areas south of the Mass Pike. With plenty of cloud cover and east to northeast winds, it definitely be cooler than it has been for a while.

Temperatures may stay in the 70s all day Friday across much of the region. Image provided by WeatherBell.

As we get to Saturday, a weak upper-level disturbance will move across the region. We’ll still have plenty of clouds, especially early, with a few showers or thunderstorms possible as the disturbance moves through. However, once it exits, skies should start to clear out late in the day, and we’ll get a bit warmer. High pressure returns for Sunday and Monday, with warm and humid conditions returning to the area.

The drought will continue to get worse until we get some significant rain on a regular basis. Image provided by the National Drought Mitigation Center.

Thursday night: Becoming mostly cloudy. Low 61-68.

Friday: Plenty of clouds with showers, possibly a thunderstorm, mainly south of the Mass Pike. High 74-81.

Friday night: Mostly cloudy with a few showers possible. Low 60-67.

Saturday: Cloudy with some showers or a thunderstorm early, some sunshine develops in the afternoon. High 75-82.

Saturday night: Clear to partly cloudy. Low 61-68.

Sunday: Sunshine and a few clouds. High 83-90.

Sunday night: Clear skies. Low 64-71.

Monday: Partly to mostly sunny. High 86-93.

Tropical Storm Isaias Nears the Carolinas

Tropical Storm Isaias is near the Carolina coastline this afternoon, but struggling to maintain its intensity.

The center of Isaias now shows up on radar off the South Carolina coast. Loop provided by Weathertap

As of 2pm Monday, Tropical Storm Isaias was centered about 115 miles south of Charleston, South Carolina, moving toward the north at 13 mph, though radar and data from Air Force reconnaissance aircraft appear to show a motion more toward the north-northeast. The National Hurricane Center says maximum sustained winds are near 70 mph, but again, data from reconnaissance aircraft show the system to be weaker than that.

Forecast track for Tropical Storm Isaias. Image provided by the National Hurricane Center.

A Hurricane Warning is in effect from South Santee River, South Carolina to Surf City, North Carolina. A Storm Surge Warning is in effect from Edisto Beach, South Carolina to Cape Fear, North Carolina, and also from Oregon Inlet, North Carolina to the Virginia/North Carolina border, including Pamlico and Albemarle Sounds. Between Cape Fear and Oregon Inlet, a Storm Surge Watch is in effect. A Tropical Storm Warning is in effect south of South Santee River to Altamaha Sound, Georgia, and north of Surf City, all the way to the Mouth of the Merrimack River in Massachusetts, , including Chespeake Bay, the Tidal Potomac, River, Delaware Bay, and Long Island Sound. North of the Merrimack River, a Tropical Storm Watch is in effect to Eastport, Maine.

Isaias should continue heading north-northeastward, making landfall near the South Carolina/North Carolina border this evening. Although the official forecast calls for the storm to strengthen back into a hurricane before landfall, this appears unlikely at this point. There really isn’t much difference between a strong tropical storm and a weak hurricane anyway, so it’s a moot point. Once inland, it should continue on a north-northeast track, moving up the coastline, steered by an upper-level trough moving in from the west. Normally, tropical storms weaken rapidly as they move over land and away from warm water, which is their main source of energy. However, Isaias will be making the transition into an extratropical storm, so it may not weaken that rapidly.

There are a few differences between tropical and extratropical storms.Image provided by the University of Rhode Island Graduate School of Oceanography

Storm surge will be a threat along the Carolina coast, near and east of where the center makes landfall. A surge of up to 5 feet above normal tide levels could result in some coastal flooding. Strong winds will also be a threat, mainly east of the storm’s center. Wind gusts of 40-50 mph have been reported just off the South Carolina coastline this afternoon. As it moves northward, some strong winds will be likely across eastern North Carolina as the storm moves inland, and possibly across eastern New England late Tuesday as the system moves across the Northeast.

The strongest winds will be east of the storm’s track and mainly offshore. Image provided by WeatherBell.

By far, the biggest threat with Isaias is heavy rainfall and the resulting flooding. The heaviest rain is likely along and west of the storm’s track. Rainfall totals of 3-6 inches and locally heavier are likely from the Carolinas into eastern Canada, which will produce flooding in many areas. The storm’s relatively quick motion will preclude even heavier totals. East of the storm’s track, rainfall will be much lighter, with many places likely seeing less than 1 inch, which won’t help with the drought developing across eastern New England.

Isaias will produce heavy rainfall along and west of its track from the Carolinas into eastern Canada. Image provided by Weathermodels.com

Elsewhere, we’re keeping an eye on a tropical wave located a few hundred miles south of Bermuda. Conditions could become favorable for it to develop into a tropical depression in a few days. Model forecasts show it heading northwestward for the next few days, staying over open water. By mid-week, most forecasts show it stalling out about midway between Bermuda and the Bahamas. It does not look like a threat to any land areas at this time.

Weekly Outlook: August 3-9, 2020

The forecast for the upcoming week is both complex and simple at the same time.

Barring a surprise, Isaias will almost certainly track to our west. Image provide by Tropical Tidbits.

We start the week off with a hot and humid day today, thanks to high pressure located over the Atlantic (more on that in a bit). Temperatures will get into the upper 80s and 90s across the region this afternoon. When you combine that with dewpoints generally in the 60s, it’ll feel like it’s in the mid 90s during the afternoon. Clouds will quickly start to stream in at night, making for a rather warm and muggy evening.

The heaviest rain from Isaias will stay well to our west. Image provided by Weathermodels.com

As we head into Tuesday, we turn our eyes to the southwest and Tropical Storm Isaias. The combination of a trough of low pressure approaching from the west and that high pressure over the Atlantic will steer Isaias into the Carolinas late tonight or early Tuesday. After that, it will start to quickly move north-northeastward, likely passing west of the region late Tuesday night or early Wednesday. Most of the heavy rain will be located west of the track, but we’ll still have some showers and tropical downpours around here late Tuesday and Tuesday night. The storm should also be weakening and passing far enough to our west to spare us from any significant wind issues. It’ll be breezy, with some gusts to 40 mph or so possible, especially along the South Coast, but overall, it really shouldn’t be too big of a deal. Once again, the hype will be likely worse than the reality.

The potential exists for wind gusts to 50 mph, but they’ll likely be lower. Image provided by WeatherBell.

By Wednesday morning, Isaias is out of here and skies will clear out, with drier air settling in as high pressure builds into the region. That high should remain in place for the rest of the week and into the weekend, with seasonably warm temperatures and comfortable humidity levels.

Dry weather for the latter half of the week will not help with the developing drought. Image provided by the National Drought Mitigation Center.

Monday: Partly to mostly sunny, breezy, and hot. High 86-93.

Monday night: Becoming mostly cloudy with a few showers possible. Low 67-74.

Tuesday: Cloudy and becoming windy with showers likely, some of them may be briefly heavy. High 79-86.

Tuesday night: Mostly cloudy and windy with showers ending, skies may start to clear late at night. Low 67-74.

Wednesday: Becoming partly to mostly sunny. High 81-88.

Thursday: A mix of sun and clouds. High 79-86.

Friday: Partly sunny. High 78-85.

Saturday: Sunshine and a few clouds. High 79-86.

Sunday: Partly to mostly sunny. High 82-89.

Tropical Storm Isaias Nears Florida, Heads for the Carolinas

While crossing the Bahamas on Saturday, Hurricane Isaias weakened to a tropical storm, but it remains a threat to much of the East Coast.

Tropical Storm Isaias continues to spin off the Florida Coast this afternoon. Loop provided by NOAA.

As of 2pm Sunday, Tropical Storm Isaias was centered about 45 miles east-southeast of Vero Beach, Florida, moving toward the north-northwest at 9mph. Maximum sustained winds were near 65 mph, and should remain near that level for the next day or two, with some fluctuations in strength possible. Tropical Storm Warnings are in effect from Jupiter Inlet, Florida to Surf City, North Carolina, with a Tropical Storm Watch north of Surf City to Duck, North Carolina, including Albemarle and Pamlico Sounds. A Storm Surge Watch is in effect from Edisto Beach, South Carolina to Cape Fear, North Carolina.

Isaias moved across the Bahamas as a hurricane late Friday into early Saturday, before weakening to a Tropical Storm Saturday afternoon. The combination of southwesterly wind shear and some dry air due to Saharan Dust contributed to the weakening. Isaias is maintaining its strength this afternoon despite the presence of more wind shear.

Forecast track for Tropical Storm Isaias. Image provided by the National Hurricane Center.

Isaias should continue to head towards the north today, in between a large area of high pressure of the east, and an approaching trough of low pressure from the west. As the trough continues to move towards the East Coast, it will help turn Isaias more towards the north-northeast and eventually northeast. On this track, Isaias will parallel the coast of Florida and Georgia today and tomorrow, then likely make landfall in either South Carolina or North Carolina late Monday night or early Tuesday. Once inland, Isaias will continue northeastward, and although it will weaken a bit, it should maintain some strength as it moves up the coast, as it starts to transition into an extratropical storm.

Storm surge will be a threat along the Carolina coast, near and east of where the center makes landfall. A surge of up to 4 feet above normal tide levels could result in some coastal flooding. Strong winds will also be a threat, mainly east of the storm’s center. Winds have been gusting as high as 50 mph along the Florida coast this afternoon. As it moves northward, some strong winds will be likely across eastern North Carolina as the storm moves inland, and possibly across eastern New England late Tuesday into early Wednesday as the system moves across the Northeast.

Most of the strongest winds should remain offshore. Image provided by WeatherBell.

By far, the biggest threat with Isaias is heavy rainfall and the resulting flooding. Some bands of heavy rain have moved across parts of Florida, and that will continue through tonight. Rainfall totals of 1-3 inches are possible across parts of Florida and Georgia over the next 24-36 hours. As you head north, heavier rain is likely from the Carolinas into the Mid-Atlantic states and the Northeast, mainly along and west of the storm’s track. Rainfall totals of 3-6 inches and locally heavier are likely, which will produce flooding in many areas. The storm’s relatively quick motion will preclude even heavier totals. East of the storm’s track, rainfall will be much lighter, with many places likely seeing less than 1 inch.

Isaias will produce heavy rainfall across much of the East Coast over the next few days. Image provided by WeatherBell.

Elsewhere, we’re keeping an eye on a tropical wave located a few hundred miles east of the Leeward Islands. Conditions could become favorable for it to develop into a tropical depression in a few days. Model forecasts show it heading northwestward, staying north of the Caribbean over the next few days. By mid-week, most forecasts show it stalling out about midway between Bermuda and the Bahamas. It does not look like a threat to any land areas at this time.