"Summer 2013 weather extremes tied to extraordinarily unusual polar jet stream"
at least the past one or two decades the adjective extreme has
increasingly become used in describing unusual weather. It’s virtually
impossible now to escape news of extreme drought, excessive rainfall and
floods, record breaking heat waves, cool spells and severe weather
outbreaks, etc. which seem to recur year after year around the Northern
Hemisphere. This summer was no different except that the behavior and
configuration of the polar jet stream, the river of high altitude winds
marking the divide between warm and cool air, were rare and
to my good friend Matt Dux for the picture below, who got quite a start
from this little guy. He said that it was only 8 hours between drive
times, so spiderman made quite a web it that short time!
about weather whiplash... how about this. PM Wednesday, there was a
report of a tornado in northern MN near Lake of the Woods and on
Thursday night/AM Friday, there were FROST/FREEZE headlines in place!
Weather Whiplash Continued...
strong to severe thunderstorms across northern Minnesota on Wednesday,
frost and freeze headlines were posted for PM Thursday/AM Friday for
temperatures expected to dip into the upper 20s in some cases! Time of
cover those tomatoes!!
Signs of Fall
don't know about you, but it feels like it's too early for Fall to be
settling in, doesn't it? Thanks to the National Weather Service out of
Bismarck, ND for the image below, which shows "Roost Rings" or birds
leaving early in the morning in search of food. They tend to spread out
in rings, which can be picked up on radar. Note how many "Roost Rings"
there are! This is one sure sign of fall!!
Heading South of Winter
another sign of fall, maybe even winter! This comes from Gates of the
Arctic National Park and Preserve, where caribou have been spotted
heading south for winter!
See more HERE:
rainfall and major flooding took place late Wednesday night into
Thursday. Rainfall reports of up to 8"+ came in over a short amount of
time with other reports of 15ft. to 20ft. walls of water roaring down
canyons. The image below is from instagram user @brandish in Boulder,
CO, where significant flooding took place.
Significant Rainfall Reports
NWS has an amazing network of CoCoRaHS reporters across the nation and
several of those users reported significant rainfall from PM Wednesday
to AM Thursday along the Front Range of the Rockies near Denver and
Boulder, CO. The pink/purple circles indicate the more significant
amount, wich near 8"+ in a few spots!
Read more about CoCoRaHS HERE:
the radar estimated rainfall suggests 4" to 8"+ across parts of
northcentral Colorado! Note the deep red color over Boulder, where
nearly 8" to 9" of rain was reported.
"A flash flood emergency Colorado killed at least three people, prompted evacuations and destroyed several roads and highways."
Read more on the flooding from 9 NEWS out of Denver, CO HERE:
Example of Rapidly Rising Flood Waters
is just one example of why flash flooding can be so deadly. Take a look
at the river rise at the St. Vrain Creek at Lyons, CO. In less than 6
hours, there was nearly a 5 foot jump in water levels.
Denver didn't see quite as much rain as folks north and west of town, but low visibility made for an interesting day there.
Why Such Heavy Rain?
a look at the water vapor imagery below from Thursday. Thanks to a slow
moving upper level low pressure system over the Southwest, tropical
moisture has been streaming up along its eastern periphery. The training
thunderstorm activity, unfortunately, is responsible for the
significant flooding reports.
another satellite image of the storm below. Interestingly, two storms
appear to be connected. The storm in the Southwest was squeezing out
significant rains along the Front Range, while strong to severe
thunderstorms were breaking out in the Northeast.
more heavy rain on the way for folks along the Front Range of the
Rockies. According to NOAA's HPC 3 day rainfall forecast, an additional
1" to 3"+ can be expected through PM Sunday.
Monsoon Season Continues...
of heavy rainfall aren't all that uncommon during monsoon season, but
this year, it is record breaking for the Bisbee-Douglas area in
southeastern Arizona. 16.25" of rain has fallen so far this monsoon
(June 15 - September 30) and we're not even done yet! The previous
record was 15.9" set in 1964.
Watching the Tropics
1st hurricane of the 2013 Atlantic hurricane season developed earlier
this week and was only 3 hours short of becoming the latest 1st
hurricane on record. Humberto will be a "Fish Storm" meaning it'll only
be an issue for ships and slow moving whales, but there's another wave
near the Yucatan Peninsula, which could become a little more interesting
over the next several days in the Gulf of Mexico/Bay of Campeche.
thing that this storm may bring is healthy rainfall to southern Texas.
Extended rainfall forecasts suggest appreciative rainfall amounts
possible through early next week. We'll cross our fingers that some of
this beneficial rainfall moves in!
Thanks for checking in and have a great weekend ahead!
Don't forget to follow me on Twitter @TNelsonWNTV