Today's Top Weather Stories
On Weather & Climate Through the Eyes of Mark Vogan
Graphic Courtesy of AccuWeather.com
BREAKING NEWS
Tropical Depression 6 Forms, Likely to Become Hurricane
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Heavy rain sparks flash floods in South Wales
BBC Weather
Hurricane Still Likely to Form in Atlantic Next Week
AccuWeather News
Are Thunderstorms Rare in Scotland?
See Weather Talk Below
Below-Normal Temperatures Return to Moscow
AccuWeather News
your america today forecast
by mark vogan
southwest
A glorious day throughout the Southwest region with low 70s for the beaches of Southern California, 60s for central and northern coasts. Look for highs in the mid-80s for downtown LA, mid to upper 70s for San Diego downtown and around 70 for San Francisco downtown, coastal valleys and canyons around LA should warm nicely into the upper 80s to mid-90s depending upon where you are, areas east of San Diego will likewise warm under sunshine and upper 80s to mid-90s. Riverside will see a hot 95 whilst Lancaster and Palmdale top around 98-100. The deserts will be once again hot with highs topping near 108-110 for Palm Springs and Baker whilst Phoenix and Vegas warms to between 107-109, Death Valley closing in once again on around 115-117. Lows tonight range from coastal 50s, mid-60s for LA, 60 for both San Francisco and San Diego, mid to upper 60s for canyons and coastal valleys and 70s to low 80s for the deserts. Spotty mtns thunderstorms can't be ruled out.
northwest
A very cool day for the beaches to I-5 corridor as well as the mountains, whilst more comfortable 80s will be had to the east oif the mountains. The trough is back and in full force with 50s likely to be the high for the beaches and mere mid to upper 60s for Seattle, near 70 for Portland with abundant clouds and fog which may have a tough time burning off around the Seattle area, Portland should see some part sunshine this afternoon. It will be sunnier east of the mountains. Tonight lows range from low 50s, even some 40s along the coast. Mid-50s for the I-5 urban corridor, 30s and 40s for the mountain communities whilst 60s should be the low east of the mtns tonight. The Great Basin and central and Northern Rockies will have a hot day under high pressure and lots of sunshine. Look for 80s to upper 90s, Lows in the 60s to around low 70s.
northeast & mid-atlantic
Today will be a beautiful day with mostly sunshine and ptahcy clouds across much of the Northeast, feeling comfortable with highs in the near-average range of low to mid-80s with 70s for the beaches. Highest temps will be as usual down around the Virginia Maryland, Delaware region where DC-Baltimore should warm under partly cloudy skies to around 87-88, Philadelphia to around 85, New York to 82 and a perfect 75 up in Boston with cooling mid-60s along the Massachussetts, Rhode Island and Connecticut coastline, perhaps a cooler 50s for the Maine coastal communities but interior New England within the sheltered valleys will be perfect with pleasant late August sunshine and temps rising into the low to mid-70s, grab a jacket for the evening hours which may drop into the 40s, it will be near 70 for the cities tonight, mid-70s for the DC to Baltimore downtowns, look for 50s and 60s across the rural areas!
southeast & florida
A classic late summer regime across the Southeast, guess what? Showers and Storms? Yes!, 80s to low 90s? Yes! TD 5's remnants remain believe it or not and this will play a factor in making for high potential for storm development this afternoon across Alabama, Georgia and as usual down into Florida where highs should warm into the upper 80s to around 90. Expect a high around 90 for Atlanta down to New Orleans this afternoon. Lows tonight range from upper 70s along coastal areas, mid to low 70s for the interior.
southern & northern plains
A hot day throughout the Plains from Houston to Rapid City where strong sunshine and highs in both of these cities should top around 97 degrees this afternoon as high pressure dominates. Whilst the central and eastern Plains warms into the low 90s it will be close to 100 degrees anywhere from western Plains to western South, even North Dakota as well as across the border into eastern Montana where some places may approach an impressive 105-degrees. There will be Front Range downslope winds and this will play a major factor in bringing 100s in spots all the way up the Western High Plains from Texas to North Dakota. Whilst Minneapolis reaches around 88, Chicago will be slightly cooler but very comfortable with a high around 83. Kansas City to St Louis should reach around 90. Oklahoma City down to Dallas will see another hot day this August with today expected to top around 100-102 whilst further south Houston will be another steambath with highs reaching 97, dew points reaching the mid-70s and heat index values reaching between 105-110. To the west and it will be blistering hot with 100% sunshine and a high around 100 for San Antonio and throughout the desert southwest interior of Texas. Lows tonight should range from 75 to 80 across the southern plains, 60s and 70s for the central and northern plains.
Today's Weather across America
From AccuWeather
Cincinnati, Louisville in Path of Heavy Thunderstorms
By Meghan Evans, Meteorologist
Stormy Weather Threatens Outdoor Plans in Northeast
By Heather Buchman, Meteorologist
Heat Relief Headed to the Plains
By Kristina Pydynowski, Senior Meteorologist
Northwest Warmth to Make a Comeback
By Kristina Pydynowski, Senior Meteorologist
Weather Talk
By Mark Vogan
WARMER AIR TRYING TO GET INTO SCOTTISH AIR SPACE, COLD AIR ABOVE, MAKING FOR NICE CLOUD FORMATIONS AND TORRENTIAL DOWNPOURS!
Despite a continued unsettled pattern with heavy showers one minute and sunshine and warmth the next, I am seeing what's going on up there by simply looking at the sky and what it's telling me, how so? Notice those clouds, their appearance, without feeling the air, their a good indicator that warmth is at the low levels... just feel it in the air. No it's not all that warm but it's certainly not cold, there's also a stickiness to the air also, even when it's cloudy, that's telling me it's coming up from the sub-tropics... that means warmer Atlantic air is coming from the southwest, not west, then look at the sky and see those towering clouds and their "dark underbelly". The good large-scale clear, sunny skies have embedded within them, large clouds and these clouds are coming from the northwest. What does that mean? Whilst surface air is coming up from a southwest direction bringing warmth and moisture (adding humidity and the sticky feeling), colder air is riding over top of the warm low-level air from a northwest direction. By Bringing these two air masses together, sliding one under or over the other you've got the ingredients in which to produce cloud formation, warmth and heavy downpours. In order for these clouds to build or rise vertically from the warm low to mid-levels into the much colder upper levels, they must rise, what will force it to rise? Surface warmth! As the sun heats the ground, this ignites the "thermals" or rising columns of air, the colder to upper levels and the warmer the low levels, the faster the air will excellerate vertically. The clouds are already there and fully formed as stratus, but these clouds then transition into what is close to becoming the classic thunderstorm cloud, the "Cumulonimbus". As the warm air is heated by the sun, bouyancy is created and with the clouds already in place, they simply build vertically, rise into the colder upper levels, as they climb, they grow, cool further and condense, producing more water droplets, eventually they rise to a point, building their droplets ever bigger until their too heavy to be supported or suspended in the air, once at that level and height of saturation, they, they then fall to the earth bringing pockets of torrential rains which create big hazrads to road users, lowering visability extremely fast.. What's stopping these towering clouds from becoming thunder and lightening producers is that they don't have enough surface heat to generate the sufficient motion in the atmosphere.
If we were seeing temps push into the mid to upper 70s or warmer, then these clouds would rise even higher bringing the right ingredients for positive and negative charging of the cloud from bottom to top, the updrafts would be stronger allowing a charging up of the cloud with downward and upward air flow, ultimately electrically charging the cloud this would happen more in Scotland if we had more heat. Stronger thermals and updrafts move the molecules faster and as they collide and rube together, tiny little ice crystals grow as they rise by collecting moisture, once heavy enough they begin falling downwards back through the cloud they climbed into at the start of their life cycle, as you descend down through the cloud, thy collide with rising water droplets and ice crystals, thus creating an electrical charge, eventually, a build-up of negative charge is accumulated at the bottom of the cloud and positive at the top, like a giant battery in the sky is created, eventually a spark is created and lightening is formed... the lightening bolt rips through the sky to neautralise the opposing charge, with this lightening bolt, comes a rumble of thunder, the shockwave the the lightening creates....
Thunderstorms are relatively rare in Scotland thanks to several factors.
Our northerly latitude means cold air masses are easier to tap than hot ones. We also are on a small island, surrounded by cool waters. Those cool waters moderate warm air masses as they travel over the UK land mass, meaning there is a limited amount of heat that can be accumulated at the surface, therefore meaning a limited intensity of upwards motion can be created... The past few days and even weeks are a great example of this, though we've been under a trough much of the summer, we have seen sunny periods and warmth (mid 60s to low 70s) thanks to two things... (1) sunshine in August is strong and heats the ground easily, (2) the air is cold aloft.. if there was stronger surface warmth, these half hearted stratus clouds would become fully fledged thunderstorm clouds but the limuted warming of the surface means they stop half way through the process, meaning all we see from these towers of the sky are eye-catching clouds and these passing overgead bringing downpours... nothing more. England being that little bit further south sees more thunderstorms thanks to warmer temperatures. We would be much hotetr in summer, even at this high latitude, if we didn't sit underneath the prevailing westerly flow and sitting right on the doorstep of the Atlantic, means milder, oceanic air masses visit more than hot, high pressure cells that migrate north during the Northern Hemisphere summer. Remember we do live close to due north of the Sahara, however these air masses need to travel over both the Med Sea as well as over the England Channel, two bodies of water that can take the heat out of the air mass itself. This is wahy central Europe, though can get hot, doesn't match those numbers seen on the Sahara.. The Med modifies and humidifies the air whilst travelling from Africa to Europe. Also it's departing it's point of origin, therefore loosing some intensity.
Though there's pleasant conditions at the surface it's be no means warm or hot, merely comportably pleasant, in fact, the clouds seen across Scotland and the rest of the UK's airspace of late is indicative to a very cold upper atmosphere associated with the trough, not so much the warmth at the surface.
During my drive in my truck between Bathgate, West Lothian and Aberdeen, I've enjoyed seeing the towering clouds and have ran into some torrential rains at times, whilst the sun is out, it feels wonderful and pretty warm. The past couple of days, it's been very nice with the best of the sunshine and pleasant weather more so between Dundee and Aberdeen with yesterday (Friday) being a particularly nice and sunny day with truck temperatures registering between 22-24C or 72-75 degrees under mostly sunny skies, this was at the same time my wife was texting me to say it was raining, cloudy and sticky back here at my house in Lennoxtown, East Dumbartonshire.
What's Reaching Today's Blogs?
Saturday Morning Severe Weather Outlook
Henry Margusity, AccuWeather
10th Accuversary (not-so) Spectacular
Frank Strait, AccuWeather
Today's Extremes here at my house
High: 65 degrees
Low: 56 degrees
TODAY'S COND
A generally breezy day with good spells of sunshine at times but also times in which there was clouds and heavy showers, becoming a little autumnal looking and feeling at times.
Thanks for reading.
-Mark
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