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DISCUSSION: As wildfires erupted across parts of the intermountain west, there continues to be a growing presence and coincident threat from associated smoke plumes. Here is a very neat perspective of the forecasted smoke concentrations courtesy of the U.S. Forest Service's Experimental Blue Sky Model as shown in the animated graphic below courtesy of the National Weather Service office in Pocatello, Idaho! Note how the orientation of the associated smoke plumes change so quickly in accordance with the change in the environmental wind direction! To learn more about other high-impact weather events from across North America, be sure to click here!
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DISCUSSION: As strong to severe thunderstorms roared through coastal sections of New Jersey earlier this evening, there are unbelievably majestic storm structure observed. One such example is the storm structure observed in and around Lakewood, New Jersey (as well as areas to the north and south of there). Having said that, in the image below, you can clearly see a picture-perfect shelf cloud moving directly over the boardwalk adjacent to the beach and shoreline in parts of Central to Northern New Jersey. The feature in the image below is a classic shelf cloud which generally forms as a result of warm air being rapidly lifted over the leading edge of the cooler air rushing away from the leading portion of the approaching thunderstorm. Along with the presence of this gorgeous shelf cloud earlier this evening there was also impressive lightning on display in association with these severe thunderstorms which affected parts of coastal New Jersey! To learn more about other high-impact weather events from across North America, be sure to click here!
DISCUSSION: As another hot day begins to slowly wind down across many parts of the Eastern United States, the worst appears to be just beginning based on the fact that over the next few days there will be persistent warm air advection out of the southeastern to south-central United States which will aid in the regeneration of sufficiently hot temperatures to warrant the issuance of the Heat Advisory discussed below! It is important to note that a heat advisory is issued when the forecast includes the likely potential for temperatures to reach the lower to middle 90s with associated heat index values close to or possibly in excess of 100°F in many places.
The primary factors which were helping to produce this persistent heatwave across much of the Central and Eastern United States is the combination of a slow moving low-pressure system across the northern tier of the country as well as a persistent subtropical high-pressure system positioned between the Eastern United States and the Western Atlantic Ocean. The combination of the low-pressure system's and the high-pressure system's position has aided in a persistent and strong warm air advection regime which has favored particularly hot temperatures across much of the eastern two-thirds of the nation for several days now. Having said that, keep in mind that dehydration and heat exhaustion can set in well before you begin to feel thirsty so continue to remain hydrated and where light colored clothing as you head out and as expressed in any current National Weather Service office forecast pertaining to this upcoming and persistent heat wave. To learn more about other high-impact weather events from across North America, be sure to click here! 
Stunning Downburst Observed Only 2 Days Ago Near Phoenix, Arizona! (credit: Severe Weather World)7/21/2016
DISCUSSION: As classic monsoon convection has gotten going in full-force over the past few days, there has been some impressive displays of fairly photogenic thunderstorms structure such as this storm which developed just outside of Downtown Phoenix, Arizona just 2 days ago. Note how you can clearly see the well-defined downburst which was generated by strong downward-motion within this thunderstorm.
Downbursts are typically generated as a consequence of strong downdrafts within the core parts of the thunderstorms which are generated as a result of persistently rain-cooled air which races towards the ground in a violent manner and spreads out. This process often generates wind speeds at the ground of up to or just over 160 MPH in some cases! Hence, these phenomena can be very life-threatening meteorological events which should always be taken seriously when they are forecast to be a legitimate possibility on a given day. To learn more about other high-impact weather events from across North America, be sure to click here! 
DISCUSSION: In the wake of an approaching cold front, several areas of intense thunderstorms erupted earlier yesterday afternoon and evening as a result of warm/moist air being lifted in the presence of an increasingly unstable atmosphere. As a result of this fairly high convective instability, a number of storms which formed in regions characterized by fairly high convective instability and decent wind shear exhibited very impressive outflow structures such as the storms captured below across parts of Central and Southern Connecticut during the afternoon/evening hours on Monday! Note the particularly low cloud-bases moving through those areas earlier in the day on Monday; likely caused large amounts of low-level moisture aiding in fantastic surface-based convective storms as seen below! To learn more about other high-impact weather events from across North America, be sure to click here!
DISCUSSION: As a weak low-pressure system slowly emerges off of the Eastern Pacific Ocean and slowly tracks to the northeast with time, increasing amounts of deep-layer moisture will gradually fill into many parts of the Southwestern United States. As this gradually occurs, the combination of variable terrain coupled with increasing East Pacific moisture will promote favorable conditions conducive for heavy rainfall. Thus, due to the inherent factor characterized by terrain-based enhancement of precipitation (scientifically referred to as orographically-enhanced precipitation). Thus, this will also promote flooding and potentially flash flooding threats; particularly within regions which are located at lower elevations (e.g., town/cities positioned within valleys adjacent to more elevated mountains/plateaus). To learn more about other high-impact weather events from across North America, be sure to click here!
DISCUSSION: As a long cold front pushed through the greater tri-state area this evening, there was quite a robust atmospheric response to the particularly hot temperatures and respectively high dew points in place through the course of the day. This response was in the form of a fairly organized line of very intense thunderstorms which initially starting developing and then quickly strengthened just to the west of Manhattan earlier this afternoon. As daytime heating continue to destabilize the lowest parts of the atmosphere across the tri-state area towards the early to middle part of the afternoon, the atmosphere quickly became primed for strong thunderstorm activity. As the nearby air parcels were lifted in the vicinity of the approaching cold front, they were lifted and destabilized which quickly resulted in the development of the aforementioned intense thunderstorm line.
More specifically, the air parcels were lifted by an atmospheric mechanism which is scientifically referred to as the "pre-frontal trough" which is the atmospheric feature that precedes the passage of a cold front and is most often affiliated with the generation of strong convective storms during the late Spring to early Fall-time period out ahead of approaching cold fronts. As seen in the video attached below (courtest of ABC7 News based in New York, New York), you can clearly see how quickly this portion of the thunderstorm line raced through Manhattan before impacting Western and Central Nassau County on Long Island before quickly dissipating due to the thunderstorm line ingesting the more stable air associated with the marine layer tied to the nearby Atlantic Ocean. To learn more about other high-impact weather events from across all of North America, be sure to click here! 
LIFE-THREATENING FLOODING ACROSS CENTRAL/SOUTHERN MINNESOTA! (credit: NWS Duluth, Minnesota)7/12/2016
DISCUSSION: As a weak low-pressure continues to produce very persistent and intense rainfall across parts of the North-Central U.S. through the rest of the overnight hours, there will be a continued and increasing threat for heavy rainfall capable of generating flooding and/or flash flooding conditions. See the details below courtesy of the National Weather Service office in Duluth, Minnesota! To learn more about other high-impact weather events from across North America, be sure to click here!
Look at that huge red blob across Kansas (Fig. 1). That feature is what meteorologists call an MCS or “Meso-scale Convective System”…To read the full story about MCS’, click here.  DISCUSSION: As a cold front associated with a relatively weak low-pressure system positioned over Southern Canada continues to slowly move eastward through the course of this afternoon and this evening, a pronounced severe weather threat remains in place across many parts of the Northeast. As of this afternoon, a broken line of strong to severe thunderstorms has erupted in a broken line extending from Northern New Jersey to near the Capital District of East-Central New York with an array of severe thunderstorm warnings as well as 1 or 2 tornado warnings being issued already. As a result of this continued severe weather threat, is imperative to keep an eye to the sky this afternoon and evening as you head out for your holiday weekend plans and be sure to take shelter in the presence of thunder or lightning so as to not put yourself in harms way. Currently, the largest threat appears to be across Eastern and Southeastern New York as well as Western Massachusetts. However, through the remainder of this afternoon and evening, the primary threat region for strong to severe storms will move east in accordance with the eastward progression of the aforementioned cold front. Be sure to stay tuned right here at the Global Weather and Climate Center for more updates later today! To learn more about other high-impact weather events across North America, be sure to click here!  |
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