>Sub-Polar Canadian high dominates Midwest to Deep South, whilst Florida Panhandle sees 50s this morning

Although we have now witnessed 11 consecutive days over 120 degrees and a peak temp reaching 128 degrees at Death Valley and much of the West has endured fierce heat, WGN-TV Chief Meteorologist Tom Skilling stated in his blog that nearly half the nation is suffering a cooler-than-normal July. Chicago ranking 5.6 below normal and having endured the second least 80-degree or higher days in some 81 years and the cooldest July so far in 42 years leads to big questions. The dominant Canadian high is keeping humidity low and trimming back temperatures to astonishingly low levels and this pattern is holding it’s own and may stand out as one of if not thee coolest July on record for some areas stretching from the Upper Midwest where it’s running 6 below normal to the mid Tennessee/Mississippi valleys.

M.V: A strong Canadian High pressure that beats the odds and pushes out the normal sub-tropical ridge from the Deep South nearly brings out the jackets for mid-July mornings along the beaches of the Gulf Coast.

What amazes me is the fact that areas such as Tennessee couldn’t buy a cool day in July and August 2007 when highs were constantly hitting the 100s, 80-degree nights were in fact warmer than recent high’s at the moment as upper 70s is about as good as it gets.

To put things into perspective, at this time of year sub-tropical ridges are normally firmly in control across AT LEAST the southern tier North America and recent years have showed stronger high pressure and covering greater areas of the US, resulting in warmer than normal conditions. What I am very surprised at is that remembering how far south in latitude the southern USA is, how cool air from Canada can penetrate south into the subtropical regions and cool nights that typically are at least 70-degrees for a low down into the 50s of course by removing the tropical humidity from the air by forcing a cold front out over the Gulf of Mexico where waters are in the upper 80s to around 90 degrees… Canadian air which has dominated the eastern half of the country over the past 4-5 days has no right being that far south in mid-July and I would go as far as to say this magnitude of cooling and the fact that under strong-July sunshine, holding highs to the mid-70s in Tennessee is remarkable, especially when this would be considered tough to do for places further north such as Chicago which has also been very cool of course.

If you look closely at the maps, there is an uninterupted flow of air from Hudson Bay to the Florida panhandle and with Fort Severn, Ontario struggling to get to 43 for a high several days ago and upper 30s by noon, this illustrates how chilly the surface air is near Hudson Bay which is still considerably frozen over in the southwest side of the bay, this ice chills the air above and has likely chilled much of the air to high levels before being transported south. This cold air is draining south via a deep trough. The depth of this trough is keeping temps from warming much in places that are hot. Lack of humidity from this sub polar origin air is allowing radational cooling even along the Florida Panhandle beaches, breezes MAY be creating wind chill believe it or not.

Western high pressure blob, helping Midwest, Deep South chills?

With the strong pressure heights that are supporting the Western heat and the contrasting deep layered trough drapped across the east, these contrasts are actually a faster flow of air from the Arctic to Deep South, greater pressure and temp differences is forcing faster flow of air and bringing it south faster, therefore meaning it doesn’t have as much time to warm further south than when the air flow is slower in the mid-upper levels.

Some interesting stats just in from the Weather Channel…. http://www.weather.com/newscenter/topstories/todayinweather.html?from=hp_news1#reclows0721

Nashville, TN breaks 132 year cold record with low of 58 degrees.

-Chattanooga, TN 60

-Pinson, AL 55

-Tallahassee, FL 60 (beats old record by 7 degrees)

-Macon, GA 56 (beats old record by 9 degrees)

There are possibly reports of low 50s in the Florida panhandle.. stay tuned for updates on that as I try to find the info..

Thanks for reading and shall post later.

-Mark