Storms have evolved into a couple of extensive, southeastward-moving linear segments over the past couple of hours. These storms have a history of occasional damaging wind gusts and isolated large hail. A few supercellular structures have been noted recently especially in southern New Jersey as updrafts interact with a nearly stationary surface boundary across that region. An isolated tornado cannot be completely ruled out here (in addition to a few instances of large hail), although the primary threat should be damaging wind gusts into the evening as storms migrate into a moderately unstable pre-convective airmass. North of the linear structures, recent convective overturning has stabilized localized areas (especially in southeastern Pennsylvania)

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Storms have evolved into a couple of extensive, southeastward-moving linear segments over the past couple of hours. These storms have a history of occasional damaging wind gusts and isolated large hail. A few supercellular structures have been noted recently especially in southern New Jersey as updrafts interact with a nearly stationary surface boundary across that region. An isolated tornado cannot be completely ruled out here (in addition to a few instances of large hail), although the primary threat should be damaging wind gusts into the evening as storms migrate into a moderately unstable pre-convective airmass. North of the linear structures, recent convective overturning has stabilized localized areas (especially in southeastern Pennsylvania)

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*As issued by the SPC* Pennsylvania remains in a general isolated thunderstorm risk. Thunderstorms extending from the Ohio Valley to the central Plains will remain capable of producing isolated strong to damaging winds this evening. Multiple clusters of loosely organized thunderstorms are present this evening from the OH Valley to the central Plains both along and ahead of a surface cold front. 30-40 kt of westerly mid-level flow across the lower Great Lakes and Mid-Atlantic should remain generally displaced to the north/east of ongoing convection through the remainder of this evening and continuing into tonight. A moist and moderately unstable airmass present from the southern OH Valley into the MO Valley

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*As issued by the SPC* Pennsylvania remains in a general isolated thunderstorm risk. Thunderstorms extending from the Ohio Valley to the central Plains will remain capable of producing isolated strong to damaging winds this evening. Multiple clusters of loosely organized thunderstorms are present this evening from the OH Valley to the central Plains both along and ahead of a surface cold front. 30-40 kt of westerly mid-level flow across the lower Great Lakes and Mid-Atlantic should remain generally displaced to the north/east of ongoing convection through the remainder of this evening and continuing into tonight. A moist and moderately unstable airmass present from the southern OH Valley into the MO Valley

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As issued by the SPC, Isolated severe thunderstorms are forecast on Thursday from Illinois eastward across Indiana, Ohio, and into western Pennsylvania. As a mid-level speed maximum moves off the Atlantic coast of the northeast states, a weak frontal wave will move off the southern New England coast early in the period. A front will extend from the southern New England coast through the OH Valley and into the central High Plains. …Lower Great Lakes and Ohio Valley region to the mid-Atlantic and southern New England…Morning convection and associated clouds will probably exist across portions of this broad region. Related outflow from overnight storm activity will also serve as a focus

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As issued by the SPC, Isolated severe thunderstorms are forecast on Thursday from Illinois eastward across Indiana, Ohio, and into western Pennsylvania. As a mid-level speed maximum moves off the Atlantic coast of the northeast states, a weak frontal wave will move off the southern New England coast early in the period. A front will extend from the southern New England coast through the OH Valley and into the central High Plains. …Lower Great Lakes and Ohio Valley region to the mid-Atlantic and southern New England…Morning convection and associated clouds will probably exist across portions of this broad region. Related outflow from overnight storm activity will also serve as a focus

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The stormy weather is not over! Here is the outlook for July 12, 2017. Scattered severe thunderstorms will be possible Wednesday within a corridor extending from portions of the upper Mississippi Valley to the lower Great Lakes region. More isolated activity is expected across the central Plains and across portions of the northern Middle Atlantic. Humidity levels will give these cells more moisture and warmer air, which will increase the severity of some isolated cells. Downstream into the northern Middle Atlantic…diurnal heating should prove instrumental in the development of scattered strong storms by early afternoon. Modest westerly flow across NY/PA suggests gusty winds could accompany this activity.

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The stormy weather is not over! Here is the outlook for July 12, 2017. Scattered severe thunderstorms will be possible Wednesday within a corridor extending from portions of the upper Mississippi Valley to the lower Great Lakes region. More isolated activity is expected across the central Plains and across portions of the northern Middle Atlantic. Humidity levels will give these cells more moisture and warmer air, which will increase the severity of some isolated cells. Downstream into the northern Middle Atlantic…diurnal heating should prove instrumental in the development of scattered strong storms by early afternoon. Modest westerly flow across NY/PA suggests gusty winds could accompany this activity.

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We all have heard of water spouts, dust devils, and tornadoes, but what about a firenado? The fire whirl is a rare occurrence in which a fire forms a tornado-like vortex of flames. These vicious cyclones of flame are also known as firenadoes or fire devils and no wonder – these babies look like they come straight out of the deepest bowels of hell! These hellish whirling dervishes of fire occur when trees, a hillside or flames force air to shift against competing air temperatures and speeds. While some fire whirls peter out pretty quickly, others can travel when the heat is able to stay afloat and surrounding gasses push it tighter

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We all have heard of water spouts, dust devils, and tornadoes, but what about a firenado? The fire whirl is a rare occurrence in which a fire forms a tornado-like vortex of flames. These vicious cyclones of flame are also known as firenadoes or fire devils and no wonder – these babies look like they come straight out of the deepest bowels of hell! These hellish whirling dervishes of fire occur when trees, a hillside or flames force air to shift against competing air temperatures and speeds. While some fire whirls peter out pretty quickly, others can travel when the heat is able to stay afloat and surrounding gasses push it tighter

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While many people may know the definitions of weather-related terms such as tornado and blizzard, the root origins of these and other terms may not be as familiar. English navigators unfamiliar with certain weather events would either ask native people about the appropriate term or invent a word themselves based on the language they already knew. Explored below are the origins of nine additional weather terms. Defined as a “widespread and usually fast-moving windstorm that can produce damaging straight-line winds over areas hundreds of miles long,” derecho originated in the late 19th century. It’s really the Latin word ‘directus,’ meaning ‘straight,’ taken in and given a sort of Spanish pronunciation so that it evolves away

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While many people may know the definitions of weather-related terms such as tornado and blizzard, the root origins of these and other terms may not be as familiar. English navigators unfamiliar with certain weather events would either ask native people about the appropriate term or invent a word themselves based on the language they already knew. Explored below are the origins of nine additional weather terms. Defined as a “widespread and usually fast-moving windstorm that can produce damaging straight-line winds over areas hundreds of miles long,” derecho originated in the late 19th century. It’s really the Latin word ‘directus,’ meaning ‘straight,’ taken in and given a sort of Spanish pronunciation so that it evolves away

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As humidity levels soar early this week, the number of communities registering highs in the 90’s will also increase. On Tuesday, high’s in the lower to mid 90’s will be common for areas surrounding the Philadelphia area. Temperatures will then continue to soar into the 90’s in these cities and surrounding areas through at least Thursday. More record highs will be challenged, and the hottest communities will be near 100 F. Average temperatures peak in July, but high’s in the 80’s are more common. Northern states especially Pennsylvania, will be dodging thunderstorms, but the cooler temperatures won’t stick around long, a heat wave will push through mid-week. While the heat wave unfolds to

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As humidity levels soar early this week, the number of communities registering highs in the 90’s will also increase. On Tuesday, high’s in the lower to mid 90’s will be common for areas surrounding the Philadelphia area. Temperatures will then continue to soar into the 90’s in these cities and surrounding areas through at least Thursday. More record highs will be challenged, and the hottest communities will be near 100 F. Average temperatures peak in July, but high’s in the 80’s are more common. Northern states especially Pennsylvania, will be dodging thunderstorms, but the cooler temperatures won’t stick around long, a heat wave will push through mid-week. While the heat wave unfolds to

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A low-pressure system will slide into the Midwest by Monday, and this boundary will help to provide some of the lift needed to produce thunderstorms. This area of low pressure will then push eastward Tuesday. Farther to the west, a separate low-pressure system will sweep from Montana into the northern Plains by midweek, bringing a risk of severe weather to those areas, as well. On Tuesday, the severe weather moves into Pennsylvania. The risk of severe thunderstorms will be found from southeast Iowa and northeast Missouri eastward into portions of Pennsylvania, New Jersey, New York and into much of New England. Portions of Minnesota, eastern North Dakota and northwest Wisconsin could also see severe storms

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A low-pressure system will slide into the Midwest by Monday, and this boundary will help to provide some of the lift needed to produce thunderstorms. This area of low pressure will then push eastward Tuesday. Farther to the west, a separate low-pressure system will sweep from Montana into the northern Plains by midweek, bringing a risk of severe weather to those areas, as well. On Tuesday, the severe weather moves into Pennsylvania. The risk of severe thunderstorms will be found from southeast Iowa and northeast Missouri eastward into portions of Pennsylvania, New Jersey, New York and into much of New England. Portions of Minnesota, eastern North Dakota and northwest Wisconsin could also see severe storms

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Often, when we think of weather, we think of moisture, atmospheric pressure, temperature and other qualifiers. However, many of these conditions don’t exist in the vacuum of space. The key components of space weather include electromagnetic energy (ie. light, x-rays), magnetic fields, and plasma – ionized or charged atomic particles. Below are some of the most prominent space weather phenomenon and some resources that you can use to monitor these events. Sunspots are cooler, darker areas on the sun’s surface. They are caused by intense magnetic activity. They are a sign of possible solar flares, coronal mass ejections, etc. They tend to cluster in bands just above and below the equator. Scientists have been

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Often, when we think of weather, we think of moisture, atmospheric pressure, temperature and other qualifiers. However, many of these conditions don’t exist in the vacuum of space. The key components of space weather include electromagnetic energy (ie. light, x-rays), magnetic fields, and plasma – ionized or charged atomic particles. Below are some of the most prominent space weather phenomenon and some resources that you can use to monitor these events. Sunspots are cooler, darker areas on the sun’s surface. They are caused by intense magnetic activity. They are a sign of possible solar flares, coronal mass ejections, etc. They tend to cluster in bands just above and below the equator. Scientists have been

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As a high pressure system hangs over the mid-Atlantic today, severe weather risks move through the Midwest. Precipitation will remain at zero today, before another low pressure system moves through on Monday. Most of the state has been placed in a marginal risk for thunderstorms, as the low pressure system moves towards the mid- Atlantic region for Monday, July 10. Some storms may be isolated and severe at times. The chance of damaging storms and wind is about one to five percent. Additional updates will be made as needed. To continue monitoring potential severe weather, follow our forecasts at Pennsylvania Weather Authority.

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As a high pressure system hangs over the mid-Atlantic today, severe weather risks move through the Midwest. Precipitation will remain at zero today, before another low pressure system moves through on Monday. Most of the state has been placed in a marginal risk for thunderstorms, as the low pressure system moves towards the mid- Atlantic region for Monday, July 10. Some storms may be isolated and severe at times. The chance of damaging storms and wind is about one to five percent. Additional updates will be made as needed. To continue monitoring potential severe weather, follow our forecasts at Pennsylvania Weather Authority.

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