Severe thunderstorm threats for parts of Northeast
Updated Jun 19, 2021 7:36 PM EDT
As usual, the most dangerous weather will affect a small fraction of the area. Here is the NWS Storm Prediction Center's convective storm forecast for Day 1, which includes the time up through early Sunday morning. Note that there is a separate marginal risk area covering northern New Hampshire and much of Maine:
Earlier today, the slight risk of severe thunderstorm threat area was painted farther north in Pennsylvania than in the midday update. This is because extensive cloudiness fanning out a head of earlier thunderstorms covered most of the area from Ohio through Pennsylvania. Such cloudiness limits the amount of daytime heating and therefore suppresses the chance for severe thunderstorms. However, even storms that do not produce damaging winds or hail can produce rain capable of causing flash flooding.
One area of concern is southeastern Pennsylvania, southern New Jersey and Delaware where it appears that some severe thunderstorms can suddenly develop late this afternoon or this evening.
In addition to the clouds and wet weather heading toward parts of the Northeast, the satellite radar composite shows Tropical Rainstorm Claudette in the Gulf states.
I think the National Hurricane Center faces administrative limitations in handling storms that are no longer classifiable according to wind but which still pose serious flood threats. In support of my opinion, here is a map produced by the National Hurricane Center on Saturday morning:
As you can see, the map only shows wind information and has nothing at all about flooding. This is not the fault of the National Hurricane Center and, in fact, other agencies within the National Weather Service produce excellent flood guidance. The partitioning of functions (creation of silos) is not just a concern in weather forecasting.
The maps below show the Storm Prediction Center's outlooks for Sunday and Monday:
This weekend is warm and more humid than recent days have been. The hottest day is likely to be Monday, but a strong cold front will move through the Northeast and Middle Atlantic regions by midweek. The following map sequence presents the forecast through next Thursday and is followed by a sampling of individual locality forecasts.
The weather forecast map for Saturday evening can be of helpful in deciding whether it could be wet where are you going to be, but you may want to keep checking your AccuWeather app to make sure about the status of any potentially severe thunderstorms, especially in the area outlined by the Storm Prediction Center. The map for Sunday shows the most significant showers and thunderstorms are likely to be in the central and western Great Lakes rather than in the Northeast.
However, the low pressure area you see over Wisconsin is forecast to move eastward with a cold front and will be coming into the East later Monday. Ahead of the front, temperatures may surpass 90° in the I-95 corridor. The cold front itself could produce severe thunderstorms, something we've already seen noted on the Storm Prediction Center's map for Monday.
The heat will be vanquished from the Northeast by Tuesday:
Unfortunately, some places that get flooding rains from Claudette will face more downpours as the cold front settles into the Southeast at midweek.
Warmth and humidity will start increasing in the Northeast later in the week.
Sample forecasts:
I often start this story with some pictures that I have taken just to set the stage for what I'm going to say. But not today.
Friday night's sunset was picturesque in my area. Do you wonder what's causing the dark column in the middle of the pinkish clouds? It is a shadow cast by some distant cloud or even a thunderstorm top. I have no easy way of determining if the cloud involved was part of a thunderstorm that visited our neighborhood a few hours later.
This morning when I was walking the dog, it felt humid and it was rather cloudy, but radar showed nothing nearby.
I like solving weather forecasting puzzles, but I've never been a fan of the kind of puzzles that many people like to work on. I thought of that when looking at this mat of flowers and noticing that it would be quite challenging if this photo was cut up into a puzzle that a hobbyist might then want to put together:
There are two more items I wanted to mention. One is the fact that it's National Lightning Safety Awareness Week starting Sunday, Father's Day. Dean DeVore, the famous broadcast meteorologist at AccuWeather, is interviewing one of the nation's leading researchers on lightning injuries as part of the podcast series "Everything Under the Sun" that regularly appears on the accuweather.com site. https://www.accuweather.com/podcast/everythingunderthesun
The second item is from spaceweather.com, where they have been commenting on noctilucent clouds.
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Weather Blogs / Northeast US weather
Severe thunderstorm threats for parts of Northeast
Updated Jun 19, 2021 7:36 PM EDT
As usual, the most dangerous weather will affect a small fraction of the area. Here is the NWS Storm Prediction Center's convective storm forecast for Day 1, which includes the time up through early Sunday morning. Note that there is a separate marginal risk area covering northern New Hampshire and much of Maine:
Earlier today, the slight risk of severe thunderstorm threat area was painted farther north in Pennsylvania than in the midday update. This is because extensive cloudiness fanning out a head of earlier thunderstorms covered most of the area from Ohio through Pennsylvania. Such cloudiness limits the amount of daytime heating and therefore suppresses the chance for severe thunderstorms. However, even storms that do not produce damaging winds or hail can produce rain capable of causing flash flooding.
One area of concern is southeastern Pennsylvania, southern New Jersey and Delaware where it appears that some severe thunderstorms can suddenly develop late this afternoon or this evening.
In addition to the clouds and wet weather heading toward parts of the Northeast, the satellite radar composite shows Tropical Rainstorm Claudette in the Gulf states.
I think the National Hurricane Center faces administrative limitations in handling storms that are no longer classifiable according to wind but which still pose serious flood threats. In support of my opinion, here is a map produced by the National Hurricane Center on Saturday morning:
As you can see, the map only shows wind information and has nothing at all about flooding. This is not the fault of the National Hurricane Center and, in fact, other agencies within the National Weather Service produce excellent flood guidance. The partitioning of functions (creation of silos) is not just a concern in weather forecasting.
The maps below show the Storm Prediction Center's outlooks for Sunday and Monday:
This weekend is warm and more humid than recent days have been. The hottest day is likely to be Monday, but a strong cold front will move through the Northeast and Middle Atlantic regions by midweek. The following map sequence presents the forecast through next Thursday and is followed by a sampling of individual locality forecasts.
The weather forecast map for Saturday evening can be of helpful in deciding whether it could be wet where are you going to be, but you may want to keep checking your AccuWeather app to make sure about the status of any potentially severe thunderstorms, especially in the area outlined by the Storm Prediction Center. The map for Sunday shows the most significant showers and thunderstorms are likely to be in the central and western Great Lakes rather than in the Northeast.
However, the low pressure area you see over Wisconsin is forecast to move eastward with a cold front and will be coming into the East later Monday. Ahead of the front, temperatures may surpass 90° in the I-95 corridor. The cold front itself could produce severe thunderstorms, something we've already seen noted on the Storm Prediction Center's map for Monday.
The heat will be vanquished from the Northeast by Tuesday:
Unfortunately, some places that get flooding rains from Claudette will face more downpours as the cold front settles into the Southeast at midweek.
Warmth and humidity will start increasing in the Northeast later in the week.
Sample forecasts:
I often start this story with some pictures that I have taken just to set the stage for what I'm going to say. But not today.
Friday night's sunset was picturesque in my area. Do you wonder what's causing the dark column in the middle of the pinkish clouds? It is a shadow cast by some distant cloud or even a thunderstorm top. I have no easy way of determining if the cloud involved was part of a thunderstorm that visited our neighborhood a few hours later.
This morning when I was walking the dog, it felt humid and it was rather cloudy, but radar showed nothing nearby.
I like solving weather forecasting puzzles, but I've never been a fan of the kind of puzzles that many people like to work on. I thought of that when looking at this mat of flowers and noticing that it would be quite challenging if this photo was cut up into a puzzle that a hobbyist might then want to put together:
There are two more items I wanted to mention. One is the fact that it's National Lightning Safety Awareness Week starting Sunday, Father's Day. Dean DeVore, the famous broadcast meteorologist at AccuWeather, is interviewing one of the nation's leading researchers on lightning injuries as part of the podcast series "Everything Under the Sun" that regularly appears on the accuweather.com site. https://www.accuweather.com/podcast/everythingunderthesun
The second item is from spaceweather.com, where they have been commenting on noctilucent clouds.