>FOR REGULAR WEATHER UPDATES (OFTEN ON THE ROAD) FOLLOW THE BLOG ON FACEBOOK & TWITTER

TODAY’S TOP WEATHER STORIES
On Weather & Climate Through the Eyes of Mark Vogan

US SEVERE WEATHER: MORE DEATH AND DESTRUCTION

At Least 17 Dead as Severe Storms Hit Deep South
FOX NEWS

Tornadoes’ death toll rises to 17 in 4 states
CBS NEWS

Storms, tornadoes kill at least 17 across the South
CNN

Record flooding has affected half a million Namibians, Red Cross says
CNN

TODAY’S WEATHER ACROSS UK & EUROPE By Mark Vogan

A high has built back in across British airspace and this will aid in rising those temperatures up into the 16 to 18C range across much of the Scottish Central Belt tomorrow (Sunday) and points northwards for areas such as Pitlochry, Aviemore and Inverness as well as places to the south such as Moffat, Hawick and across to Dumfries where there sould be pleasant and warm sunshine with light winds. Slight sea breezes will keep coastal areas cooler than inland, perhaps 14 to 16C for such places as Stranraer, Girvan up to Largs in the west, Kirkcaldy, Arbroath and Aberdeen harbor in the east. On the Scottish West coast, temperatures in spots may struggle to top 11 or 12C if winds are more brisk, the flow is slight westerly and this may trim temperatures on the islands and west coast that are open to west winds off the Atlantic, Minches and even the Firth of Clyde, same goes for West coast of Englanbd and Wales.

Areas up and down the west, south and east coasts of England will warm slightly more than across the Scottish coasts, perhaps reach 17 or 18C with inland areas widely reach 18 to 20C with perhaps the odd 21C this afternoon around Greater London.

Moderate strength High covering much of Europe portrays mild temps but cloud and showers remain a threat

Despite a high covering much of the continent, it’s not a particularly strong one, thus pressure heights aren’t strong enough to erase or burn off mid-level cloud formation and therefore surface temperatures stretching from Amsterdam to Berlin will range from around 15 to 18C, not far off seasonal averages for this mid point in April and it’s certainly not nearly as warm as a week to 10 days ago. The large-scale flow is coming from the Atlantic Ocean and not directly up from Africa and Spain. Conditions are cool enough aloft to support snowfall in the Alps of Austria, Switzerland and Italy as well as the mountains of northern Norway and Sweden.

Interestingly, some of the strongest ‘heights’ (warmest temps aloft) from this large high stretching from the North Atlantic all the way to central Europe, will be over Scotland tomorrow!

In tomorrow’s Euro, I shall look at the weather week ahead across Europe… Stay tuned. 

TODAY’S WEATHER ACROSS AMERICA By Mark Vogan

This Evening is the Final Phase of the current Severe weather outbreak

After a rough afternoon across the Carolinas, Virginia and the urban corridor from Washington to Philly, the severe weather threat will linger over the eastern Carolinas including the Outer Banks and perhaps extremes southeast Virginia also.

Mid-Atlantic within a pocket of unstable and unpredictable atmosphere!

Because there is currently a large area of relatively strong thunderstorm cells with pockets of intense thunder, lightning, rainfall and gusty winds clustering within an atmospheric box, sandwiched between eastern Virginia & North Carolina that runs north all the way to New York City. The boundary of these storms is the front to the west, warm front to the north and Atlantic to the east with a strong and moist southerly flow racing up and fuelling these storms. The problem is, some of these could become severe through this evening. As you can see from the below graphic, there is strong thunderstorm cells forming across the eastern coastal plain of stretching from North Carolina all the way to New York.

Warmth finally builds once again across the Desert Southwest, but for how long?

With all the troughiness now centered over the East thanks to the carving out from the storm system, we’re seeing a nice ridge pump warm air northwards from Mexico and throughout the West all the way up into the Pacific Northwest today. Across the deserts, highs today will top the 90s in places like Phoenix, a huge difference from the upper 50s to low 60s during mid last week, thanks to the early effects of the storm now exiting the East. The LA basin will see sunshine and upper 80s whilst beautiful 70s create a perfect weekend beach day!

WEATHER TALK
By Mark Vogan

After this killer storm exits the US East Coast tonight, another already awaits to move out onto the playing field! This time next week may be a similar story

This pattern will continue, the end in sight will be ‘summer’.

KEY ELEMENTS IN PRODUCING A PATTERN SIMILAR TO the RECORD 2008 TORNADO YEAR

1) Fading La Nina
2) Warmer Gulf waters
3) Colder-than-normal S. Canada
4) Active Pacific jet stream

The pattern that has been somewhat hyper-active in the last 3-4 weeks I believe is down to the type of winter we’ve seen across the Lower 48, the fading of what was a strong La Nina and that is having major implications in the upper-level set-up above the US and further afield. At the surface, we’re seeing warmer than normal Gulf of Mexico sea surface temperatures and this is a fuel, feeding the atmosphere when those Pacific systems cross the Rockies and out over the Plains. Once these huge machines of air get across the Rockies, they pull air from the south. If those Gulf waters are warmer, then the air getting injected into the storm will have more fuel both in heat and perhaps more importantly, humidity!

The problem, like in 2008 is the fact that the La Nina tends to produce cooler than normal springs across the Northern tier of the country. This air too gets sucked down by the storm, infuse the two together over the Plains and it’s the highest available fuel to run the huge atmospheric engines.

THE SPRING ATMOSPHERE OF 2011 IS PRIMED FOR MAXIMUM SUPERCELL DEVELOPMENT

Those two air masses of large departure from normal increase a cross-continental jet flowing in off the north Pacific. That too increases deepening of storms over the Plains and enhances ‘lift’ and the lapse rate, ‘cape values’ and the ability for the atmosphere to excellerate from low to upper levels. A stronger lapse rate (rate of cooling in the atmosphere with height) and greater thermal contrast within a short distance means taller, stronger thunderstorms can fire up alone a strong cold front. The strong front and the excelleration of south winds ahead of the front, combined with a powerful northwest upper-level jet creates the rotation along the boundary for thunderstorms to transition into rotary supercell beasts. Those are the dangers out there in producing tornadoes.

WHAT’S REACHING TODAY’S BLOGS?

Tornado Watch Issued for Parts of the Region
PhillyWeather
 
Travel delays likely Saturday in heavy rain
Maryland Weather

WHAT’S ON TODAY’S WEATHERBELL BLOGS?

Severe Weather Pattern Ramping Up, ala 2008
Joe Bastardi’s Blog, WeatherBell.com

Ingredients for continued stormy regime ahead
Joe D’Aleo’s Blog, WeatherBell.com

THE EXTREMES OF THE DAY

TODAY’S US EXTREMES
COURTESY OF ACCUWEATHER

HIGH: 100 degrees at Yuma, AZ
LOW: 7 degrees at Clayton Lake, ME

TODAY’S UK EXTREMES
COURTESY OF THE MET OFFICE

HIGH: 67 degrees (19.3C) at Astwood Bank (Buckinghamshire)
LOW: 33 degrees (0.7C) at Bala (Gwynedd)

TODAY’S EXTREMES HERE AT MY HOUSE

HIGH: 53 degrees
LOW: 46 degrees

Thanks for reading.
-Mark