Archive for August, 2007

Only Rain Down the Drain
August 23, 2007

Go to the Illinois Watershed Partnership website to win prizes at WWW.IRWP.ORG

It is estimated that when rain falls on natural landscapes like forested areas, approximately half of the rainwater soaks into the ground, another 40% is lost into the atmosphere through evapotranspiration, and another 10% moves off-site through stormwater runoff. However, with urban development, increased impervious surfaces prevent much of the stormwater from naturally soaking into the ground. Instead, much larger volumes of runoff flow from rooftops, over paved areas, on saturated or compacted soil and across sloped lawns.

One impact of stormwater runoff is the collection and transport of soil, pet waste, pesticides, fertilizer, oil and grease, leaves, litter and other potential pollutants that are transported through storm drain systems. In a city, stormwater runoff entering a storm drain is discharged, untreated, into the waterbodies that our local communities use for swimming, fishing, and providing drinking water.

A second effect is the increased volume and speed that the stormwater generates as it is concentrated through the smooth, straight storm drain pipes. When this stormwater runoff reaches the drain outlet and empties into the receiving stream, the intense volume and power has a tremendous erosive effect on streambanks.

You don’t need a heavy rainstorm to carry pollutants into streams. Your home garden hose can supply enough water if you are washing your car in driveway, hosing stains or spills off the pavement or letting excess irrigation water spray into the street. Even if your home is not on a streambank, storm drains along your street gutter carry stormwater runoff from your neighborhood to the nearest body of water.

Stormwater is unavoidable, but you can minimize its effects by:
1) reducing the potential pollutants you might contribute before they are picked up in runoff
2) enhancing infiltration and reducing stormwater runoff


August 22, 2007

Take a close look within the eye of Hurricane Dean. There are actually several distinct sub-vortices, spiraling around within the center of the eye. Large Hurricanes often develop such phenomena. The spin around the center induces these smaller spins that also revolve in a counter-clockwise flow. Check out the still picture below.

The picture highlights possibly a “trio” of sub-vortices, though check out the picture below of Hurricane Isabel. Isabel remained a CAT5 for many days while at sea. During this time the eye did some amazing things such as captured in the image. This shot actually displays five distinct vortices, cycling around a center one.

Temperature spread!
August 22, 2007

This is an IR (Infrared) image from the polar-orbiting NOAA-18 satellite, displaying the eye of Hurricane Dean about 1 hour prior to landfall. Chetumal, Mexico is just to the south south west of the Eye (MMCM). The coldest IR brightness temperatures in the northern eyewall region were -83º C / -117 º F (black enhancement), while IR brightness temperatures within the eye region were as warm as +20º C/ 68 º F.

Just imagine… “expect a high of 68 F today with an overnight low of -117 F” :-o

Atmospheric Protection
August 21, 2007

The Gulf Coast is never usually hurricane proof, but we became protected when it came to Hurricane Dean’s track. A dominant ridge of high pressure has been established across the southeast, which helped to keep Dean to our south. I have highlighted that high in the picture above. Notice the easterly upper level winds near Dean. Instead of turning north, Dean basically moved due west through the Caribbean.

Typically this high during the late summer sets up off the east coast near Bermuda. Meteorologists call this a “Bermuda High”. That particular situation helps to usher systems into the Gulf where they move northwest toward the coast.

Fortunately, we had some atmospheric protection, but this gift may not last. The season will peak in the middle of September, so we have a few more months of the tropical weather season to endure. Stay tuned!

Sunlight is Ticking Away
August 21, 2007

The hot summer sun is relentless, and we’re definitely getting a taste of the heat this week. Here’s a thought to cool you down, we’re losing daylight each day; moreover, less daylight means we’re moving toward fall, and that means an opportunity for cooler weather.

Today the sun rose around 6:42 a.m. and will set around 8:00 p.m. On August 31 the sun will rise at 6:49 a.m. and will set at 7:46 p.m. What a difference a few days makes. We lose around 21 minutes of potential heating from today until the last day of August. Less light means less heating, so think about that when you’re sweating bullets in the 90 degree heat.

From Dean to Increasing Heat
August 21, 2007

How nice was this past weekend? Ok, we could have used a lot more rain, but the clouds and the 80 degree temperatures were perfect. Unfortunately, August heat is returning, and with a bit of a vengeance. I admit I thought after the weekend we were on the downhill slide, whoops, bad error in judgement. Come on, you know you had the same thought! This is Arklahoma, and September can be a scorcher! Take a look at the 90 day outlook for our area. Looks like the chance for above average temperatures will carry us right into fall. 850 temperatures increase this week, so expect highs in the 90s right into the weekend.

On the other hand, I should not be complaining about our tranquil weather. My heart goes out to those impacted by Hurricane Dean. This storm is a Category 5 monster! Jamaica for the most part was fortunate, but look at this satellite picture of the Yucatan Peninsula. Here is a picture of Dean while he was a minor tropical disturbance. It’s hard to believe a blob of convection can turn into something so organized!

Jamaica’s Close Call
August 19, 2007

Right now Dean is a violent category 4 hurricane passing over the island of Jamaica. Fortunately, the eye wall has dodged the island, but hurricane force winds continue to pound the small island. Look at the pictures above! Talk about a close call.

The center of Dean was located about 70 miles west-southwest of Kingston, Jamaica. Reported sustained winds on the island have ranged from 80 to 100 mph. Maximum sustained winds within Dean are estimated at 145 mph.

Dean could strengthen into a category 5 hurricane before plowing into the Yucatan Peninsula on Tuesday.

August 18, 2007

Model consistency is still very grouped in a mean westward track for Dean, though just a slight jog to the north in the long-range track would put the TX coast directly in the line of fire.

In mph these are 177 mph winds!

Surface winds, presently at a sustained 150 mph, make Dean a strong CAT 4 and just 5 mph shy from a CAT 5. An upgrade will likely take place later today. Central pressure is good gauge of strength; the lower, the stronger. Presently Dean is at 930 mb.

FYI: Katrina at its strongest had a central pressure of 902 mb, though it hit with a pressure of 918 mb. Wilma, also of the 2005 season, holds the record for the lowest pressure ever recorded for an Atlantic hurricane, 882 mb.

2007 Updated Hurricane Forecast
August 17, 2007

Now that Emily and Dean have come about quickly, it’s now time to re-visit the predictions for the rest of the 2007 year. The National Hurricane Center forecasts an 85% chance for an above normal 2007 tropical season. They also go on to predict between 13 to 16 named storms.

The peak of the hurricane season is typically during the month of September, and eventually weakening throughout October. Take a look at this graphic from the National Hurricane Center. These are the conditions that make the case for an above average year.

August 16, 2007

Dean “officially” became the seasons first hurricane as of the 5:00 AM update from the National Hurricane Center / Tropical Prediction Center (NHC TPC). Winds are presently sustained at 80 mph with gusts to 90 mph. By 120 hours the storm is forecasted to be a major Hurricane, with winds just about up to 150 mph! If it goes just to the north of the present track, sliding by the Yucatan peninsula and Cuba, then it’s in the Gulf. Time will tell.