From the ABC 7 Weather team

Archive for category The Outside Story July 2014

Cooler and comfortable end to July

July 26, 2014 - 06:00 AM
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After a hot start to July with eight of the first fourteen days above 90 degrees, the pattern shifted. Since then, high temperatures topped out in the low to mid 80s seven times and reached 90 degrees only once.

Looking ahead to the end of July and the beginning of August, temperatures are still expected to be cooler than normal. Once we get through the weekend, which will feature more heat, humidity, and the chance for showers and the possibility of severe storms, cooler air is forecast to filter in next week.

500mb vorticity plot for next Tuesday

While a large ridge is expected to continue to build over the southwestern U.S., a potent shortwave will move through the Midwest and into the Northeast this weekend bringing the potential for severe storms.

This shortwave will spin around an area of low pressure centered over the eastern part of the Hudson Bay in Canada (above), which looks like it will be blocked from moving anywhere as high pressure sets up east over Canadian Maritimes and the northern Atlantic.

6 to 10 day temperature outlook from the CPC

In reality, what does this mean for the D.C. area? Temperatures may only approach the 80 degree mark Tuesday and low to mid 80s Wednesday through Friday of next week. In addition, humidity levels should be low, with dew points in the 50s expected Tuesday through Thursday before more moisture slides back into the region Friday.

Tuesday afternoon 2-meter temperature anomalies (Credit: WeatherBell Models)

With record heat dominating the headlines, including the hottest global June on record per NOAA, this will most certainly be enjoyed throughout the eastern half of the U.S. next week. Portions of the eastern U.S. will enjoy afternoon temperatures 10 to possibly 20 degrees below the seasonal average.

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Severe Storms Possible Sunday and Monday

July 25, 2014 - 03:07 PM
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Say goodbye to the beautiful weather of Friday and hello again to summer in Washington, D.C. for the weekend. That means a return of heat and humidity as well as a return of summertime thunderstorms. Saturday will feature very warm temperatures, right around 90 degrees for a daytime high with increasing clouds and increasing humidity late in the day. Another thing that will increase on Saturday will be the chances of showers and thunderstorms. Albeit, it is only a slight chance of showers and thunderstorms through the PM and overnight hours on Saturday, but still a chance.


An upper level piece of energy will approach the region on Saturday night. Mainly our western areas will be the breeding ground for any action, but by Sunday, we all have equal chances to see showers and thunderstorms across the area as that disturbance passes through the D.C. area.

ZZZZZ

 

Also what we are watching after Sunday’s disturbance is a very strong cold front will be dropping out of the upper Midwest and down into the region for Monday. Therefore, we have a chance of showers and thunderstorms Saturday night – Monday, some of which could be strong to severe.
Above graphic, at the top, shows the slight risk area for severe weather Saturday through Monday. The risk moves from the Ohio Valley Saturday to our area on Sunday and Monday. On the bottom of the graphic, the surface features show an area of high pressure overhead bringing us very pleasant on conditions on Friday. Then through 8 p.m. Saturday, the area of high pressure scoots off the coast giving us a southerly flow bringing humid air from the south and transporting it right here into the D.C. area as a warm front approaches the region. By Sunday and Monday morning, the strong cold front is still to the north and west of the area.


So now that we know what is going on, what can we except through the weekend? Well considering that warm front is just to the south on Saturday night, lift from warm advection around the warm front and the piece of energy approaching us from westerly flow aloft will give us that about a 20% chance of storms on Saturday afternoon and evening continuing through the overnight hours. There will be a good chance of severe weather across our area through the day on Sunday as that disturbance moves through the region. One thing that still remains a question is temperatures on Sunday. Right now I have temperatures fairly warm, nearing 90 degrees. But, if we get some thunderstorms in the morning hours, that could down our temperatures for the afternoon and lessen the instability in the atmosphere. Either way, it will still be very muggy outside through the day on Sunday with mainly clouds hanging around. Some of our models do suggest that we get some thunderstorms during the first part of the day on Sunday.

 

ZZZZZ

 

Caption: Showers and thunderstorms around the region weaken slightly as they travel to our area from the north and west. This is around 11a.m. on Sunday.

We do know that any of these storms could produce damaging winds, possible hail and heavy rain. There will certainly be substantial moisture around the region given the nice southerly flow, therefore localized flash flooding is definitely a concern. Take a look at our precipitable water values:

 

ZZZZZ

 

You may have heard this term or “PWATS” quite a bit this summer. Really what preciptable water values are are the amount of water within a vertical column above the surface if it were all precipitated out. These values are over 2.00” in some spots and when we see that, we know there is enough moisture available to create flooding conditions.


By Monday, the chance of showers and storms remains through the day as the cold front finally travels through the region. Again, some of there could be strong to severe but by Tuesday, we are in for another treat.

ZZZZZ

A nice refreshing airmass moves into the region bringing low humidity and refreshing temperatures. Daytime highs on Tuesday are in the upper 70s to lower 80s! We just got to make it through some summertime storms to get the reward by mid-next week!

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45th Anniversary of Landing on the Moon

July 20, 2014 - 05:00 AM
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"One small step for man, one giant leap for mankind".  These are the words Neil Armstrong said 45 years ago today after he stepped onto the surface of the moon.

Astronauts Neil Armstrong, Buzz Aldrin, and Michael Collins were all aboard the infamous Apollo 11 flight to the moon.

NASA

The three launched into space aboard Apollo 11 on July 16, 1969 via the Saturn V rocket at the Kennedy Space Center in Florida.  Armstrong and Aldrin then climbed into the lunar module Eagle (below) that would descend onto the moon, while Collins orbited in command module Columbia.

NASA

At 4:18pm EDT, Armstrong connected with mission control in Houston saying "Houston, Tranquility base here.  The Eagle has landed". 

At 10:56 pm EST, Armstrong set foot onto the surface of the moon.  You can see in the image below the American flag the astronauts planted on the lunar surface.

NASA

Buzz Aldrin then joined Armstrong on the moon and the two spent time deploying instruments that would be used for experiments, gathering samples of lunar soil, and taking pictures. 

Here's a great "Moonwalk Montage" that takes us back to that day:

 

The three astronauts accomplished something the Russians had not.  NASA states they did not want to focus on the "victory" of the mission, but rather emphasized the "peaceful lunar landing by the United States. 

The patch designed for the mission was created by Michael Collins.  On the patch, the American Bald Eagle is depicted landing on the lunar surface, delivering an olive branch of peace.   The words "Apollo 11" were chosen for the top of the patch above a distance crescent shaped Earth.

NASA

The United State's determination in exploration through the Space program has taken us to the point where we now have a rover on Mars.  The mission 45 years ago today reemphasizes the spirit of our country and the desire to explore and discover outer space.

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Rocket Launch from Wallops on Saturday

July 10, 2014 - 07:04 AM
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First it was engine trouble and then thunderstorms delaying the launch of an unmanned commercial rocket that will resupply the International Space Station.  As of today, all signs point to a "go" for the Cygnus Rocket launch at 1:14p.m. on Saturday at Wallops Flight Facility in Virginia. The rocket was rolled out onto the pad this morning at Wallops as shown here in a tweet by NASA.


Antares Rocket on the Launch Pad at Wallops Flight Facility

 The rocket will be carrying 3,300 pounds of supplies for the ISS, including food, science experiments to expand the research capability of the space station's Expedition 40 crew members, and tools.  Many student experiments will be on board as well.  This is the second of eight scheduled rocket launches for Orbital Sciences, a private company based in Virginia that has a contract with NASA for the resupply  missions.


Orbital Sciences

 Although the launch will take place in the daylight hours, the burn off from the rocket may still be bright enough to see, even here in Washington, D.C.  Weather looks cooperative with partly cloudy skies forecast. You need to look at about 5 degrees above the  horizon in the southeastern sky about a minute or two after the launch.  Here is a map where it would be visible.

 


visibility of launch expected from Orbital Sciences

 You can also watch it live on NASA TV starting at 12:30p.m. ET.  If the launch happens on time, it will reach the International Space Station on Tuesday, July 15th. 

 

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Arthur Update and Fireworks Forecast

July 4, 2014 - 09:05 AM
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Hurricane Arthur has put a damper on numerous firework's displays with many locations having to postpone or cancel.  Fortunately for us, the fireworks should be able to get off without a hitch in the Nation's Capital.  Here's a list of cities where fireworks have been rescheduled.

Hurricane Arthur made landfall near Beaufort, N.C. around 11:15 p.m. Thursday night.  Arthur was downgraded to a category 1 hurricane with winds at 90 mph as of the 9 a.m. update from the National Hurricane Center.  The storm has moved off the coast of the Outer Banks, NC and is quickly moving northeast.
(National Hurricane Center)
As a cold front slides through our area and Arthur moves farther out to sea, skies will clear from west to east, as drier air filters in.  It'll also be quite breezy, with winds gusting to around 30 mph through the day.
Winds will subside by the time the fireworks are set to go off downtown at 9:10pm.  And we couldn't ask for a more pleasant fireworks forecast.  It will be very comfortable, with low humidity and still just a bit breezy.  Click here for a full list of Fourth of July parades, events, and fireworks' displays.
The rest of the holiday weekend looks fantastic!  The humidity will remain low with plenty of sunshine and seasonable temperatures.

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