Hurricane Season Starts Monday

Tomorrow...June 1st...is the official start to the 2009 Atlantic Hurricane Season. Right now the tropics are very quiet, but we will be watching off the eastern coast of Florida for some potential development later this week (wind shear will be weak in this area).

Instability Showers

Isolated showers have again popped up in the area. This time they have developed in northern Hanover and King William counties. These type of showers will be possible across the entire area until after sunset.

Given the fact that these showers are very isolated, the chances for rain will remain slim. I will have an update during the 6:30 PM newscast!

Rain Likely This Morning

A line of showers and isolated thunderstorms has now entered into Central Virginia. These are racing to the east at 40 mph. Although I'm not expecting these storms to cause widespread damage, we should see strong wind gusts and very heavy rain while they pass. I will be tracking them during the morning newscast from 6 to 8 AM, see you there!

Showers Headed This Way

Spotty showers are just to the west of the Blue Ridge and are headed this way. Once they pass the mountains, they will weaken; however, I still expect some rain to make it into central Virginia tonight. Showers will linger into tomorrow morning, then taper by the afternoon.

Isolated Showers In The Area

Two or three showers have developed this afternoon and are quickly moving to the southeast. If you encounter one of these showers, expect a brief downpour and maybe a clap of thunder. Chances for rain will otherwise remain very slim for the rest of the afternoon and evening.

Nice Start To The Day!

Humidity levels have dropped off significantly since last night. You will definitely feel it in the air today, so enjoy it! I'm tracking a small storm in the upper Midwest this morning which could bring a few sprinkles to the area tonight. Otherwise, most of this weekend will be dry and comfortable.

Severe Thunderstorm Watch Extended Southward

Another Severe Thunderstorm Watch has been issued for the southern half of our area and is in effect until 10 PM.

Watch Likely Farther South

Conditions are becoming more favorable for severe storms to fire south of I-64, so a Severe Thunderstorm Watch could be issued very shortly.

Severe Thunderstorm Watch Until 8 PM

A Severe Thunderstorm Watch has been issued for the northern half of Virginia and is in effect until 8 PM this evening. Strong thunderstorms capable of damaging winds and/or large hail will be possible this afternoon and evening. We will have more updates as conditions warrant.

Stay with CBS 6, we'll keep you ahead of the storm!

Strong Storms Possible Friday Afternoon

Strong to severe thunderstorms will be possible Friday afternoon across Virginia as a cold front pushes through the state. Ahead of the front is ample low-level moisture and peak heating into the mid- to upper-80's. As the front progresses, it will serve as a lifting mechanism for further storm development. Any of the storms that form this afternoon will be capable of heavy downpours, frequent lightning, and gusty winds. The severe storms will be able to produce large hail and damaging wind gusts.

The visible satellite image at 12:30 p.m. Friday shows the developing thunderstorms in northern Virginia.

In fact, you can see the cumulus development along and ahead of the cold front as it progresses toward the Appalachians. Also notice the clearing in Ohio behind the front. This front will sweep out much of the low-level moisture that has been in place across the region all week, and bring dry conditions for the weekend.

--Carrie

Close...But Not Ana

Tropical Depression One continues to track East-Northeast at 15 mph through the Atlantic about 500 miles Northeast of Virginia Beach, or about 260 miles Southeast of Nantucket, Massachusetts.

Maximum sustained winds are still at 35 mph, which is not quite to Tropical Storm strength. If TD One could have reached 39 mph sustained winds, it would have been dubbed the first named storm of the 2009 Atlantic Hurricane Season, Tropical Storm Ana. It is close, but probably not going to happen today as the storm moves into the colder waters of the North Atlantic. The low pressure system will lose its tropical characteristics as it accelerates further into the North Atlantic, not threatening land. For the latest on TD One, click here.

Showers Continue To Develop

Showers and isolated thunderstorms have blossomed this early afternoon, especially along and west of I-95. The threat for rain will continue for the entire area into the evening.

Atlantic Hurricane Season Starts Early!

The first tropical system of the 2009 Atlantic Hurricane Season has formed today! Tropical Depression One is moving northeast in the Atlantic east of Virginia. For the latest information on One, click here. This system may become Tropical Storm Ana if it strengthens over the next day.

The official start of the Atlantic Hurricane Season is June 1.

--Carrie

Front Friday To Sweep Out High Humidity

Central Virginia has remained in a warm, humid air mass all week. For those of you who are not pleased with the soupy atmosphere, relief is on the way! A cool front is currently moving through the Midwest (click this morning's image below to enlarge).

This front will sweep through the Commonwealth Friday evening, pushing the deep moisture to our south. Until that front moves through, though, there will be chances for scattered showers and thunderstorms both Thursday and Friday afternoon. Ahead of the front Friday, there may be some strong thunderstorms that develop east of I-95, capable of producing damaging winds.

After the front passes, dry and warm weather will be in place for the weekend!

--Carrie

D.C. Downpour Tuesday Morning

The Washington D.C. metro received quite a downpour Tuesday morning, smack-dab during the first morning commute after the holiday weekend. Parts of the area picked up one to two inches of rain in an hour alone, putting rain totals this morning in just a few hours at two to three inches. Part of the reason why there have been such high rainfall accumulations is because of how slow-moving these showers have been, drifting to the north at just five miles-per-hour. You can get hourly weather readings and rain totals for the D.C. airport here.

Because of the heavy rain in a short amount of time, and in a metropolitan area (i.e., lots of concrete), a Flash Flood Warning is in effect until 11:30 a.m. Tuesday for the entire D.C. metro region. An additional accumulation of one to two inches is possible before this batch of rain finally passes northward. Excessive runoff is a concern in metro areas because of limited natural locations to absorb the water. Instead, highways and underpasses tend to be the popular water collection location until the influx flushes out of the concrete jungle. So far, there have been several motorists rescued from vehicles stranded in high water this morning, and some roads have been closed.
--Carrie

Warm, Humid Until Weekend

A warm, humid air mass will remain in the Commonwealth through the end of the work week, with at least a slight chance for afternoon showers and thunderstorms each day. A cool front will move through Central Virginia Friday evening, though, and sweep out the higher levels of moisture. This will bring drier, but still seasonably warm, air to the region for the weekend.
--Carrie

Memorial Day: Chance Showers & Storms

For the Memorial Day observance today, the Commonwealth and much of the Southeast remain in a humid, warm air mass. This type of environment is conducive to afternoon scattered showers and thunderstorms, where brief downpours with some lightning strikes are possible. Winds can become gusty as well, up to 40 mph. During outdoor activities today, have a back-up plan in place in case one of those showers/storms moves over your location. Do not underestimate the threat from these quick hit-or-miss downpours, because these can be accompanied by lightning strikes! Seek shelter until the shower/storm has passed, and resume your enjoyment and observance of the holiday.

--Carrie

Watching The Tropics

Right now the polar jet stream is all the way up into Canada, while the sub-tropical jet looms over the Gulf of Mexico. Wind shear will be weak in between both of these area in the coming days.

Latest data shows a low pressure developing a few hundred miles off the eastern coast of Florida by Tuesday. This low could possibly take on some tropical characteristics, however, the chances are looking pretty slim at this point. Nonetheless, we will be carefully watching this area in the coming days and will keep you posted!

Flooding In Daytona

The past several days have been generally dry in our area, especially when you compare our rain totals to parts of Florida.


Rain totals 5/16 to 5/22

Over 17" of rain fell near Daytona Beach, which resulted in widespread flooding in the region. Check out these photos from the Speedway!



(Courtesy of Autoweek.com)

Close But No Cigar

The storm system along the Gulf Coast almost became a tropical depression earlier this morning. However, it has now moved inland and will gradually weaken over the next few days. Some of the moisture associated with this system will migrate into our area, so isolated showers will be possible tomorrow and Monday.


Satellite/radar loop from this afternoon - notice how the circulation is now inland.

Summer Climate Outlook

The Climate Prediction Center issued its Summer Climate Outlook for June, July, and August 2009 this morning. These three-month outlooks are usually heavily influenced by what is going on with the El Nino Southern Oscillation (ENSO) cycle. However, in the Spring this year, the Equatorial Pacific transitioned from La Nina conditions to ENSO neutral, meaning that there are no significant anomalies of sea surface temperatures in that region, either much warmer or much cooler than average. So in the absence of a strong climate driver like El Nino or La Nina, forecasters must rely on recent trends in precipitation and heavily on climate model output for a long-term outlook.

Here is the national temperature outlook for June-August 2009, where the blue shades indicate below-average temperatures and the orange shades indicate above-average temperatures. The Commonwealth has a chance of warmer-than-average temperatures for the Summer months this year.





As for precipitation, most of the country has equal chances (EC) of being either wetter or drier than average this Summer, including Virginia. The green shades indicate wetter than average conditions, while the orange shades indicate drier than average conditions.


In other words...this Summer's outlook just might be any one's guess in the absence of an obvious influence like El Nino or La Nina. This is pretty much what a slew of computer models "think" will happen.
--Carrie

Update Thursday Mid-day:
NOAA also announced its 2009 Atlantic Hurricane Season Outlook this morning, and they are predicting an average hurricane season, which means there is a good chance for "nine to 14 named storms, of which four to seven could become hurricanes, including one to three major hurricanes (Category 3, 4 or 5)." Again, because of the absence of an El Nino or La Nina, there is no significant, possible driving influence on hurricane formation or inhibition. Basically NOAA is saying it is important to be prepared for tropical cyclones if you live within a couple hundred miles of the coast (remember, there is the flooding threat from heavy rain that exists from tropical systems moving inland). For more on how to be prepared for hurricane season, click here.
--Carrie

Look East Before Dawn Thursday

A lovely space sighting will occur Thursday morning before dawn (sunrise Thursday in Richmond is at 5:55 a.m.), so set your alarm early if you want to witness the show! Look to the east and you will see a triangle composed of the crescent Moon, Mars, and Venus (in that order from left to right as you look east).

(Image: SpaceWeather.com)

--Carrie

Hump-Day High & Florida Flood

High pressure remains over the Commonwealth and the Mid-Atlantic Wednesday. Sunny skies, gradually warming temperatures, and a return to Southeasterly winds will be the result of this high pressure in our region. With such pleasant conditions, there must be an opposite somewhere, like the balanced yin and yang.

(Click to enlarge)

Sure enough, the Sunshine State remains under the influence of the low pressure system parked just off Southwest Florida. This storm system is barely drifting westward at the moment, and continues to spin over the state, dumping inch upon inch of rain. Check out some of the totals so far from this system.

...SELECTED STORM TOTAL RAINFALL IN INCHES FROM 800 AM EDT MON MAY18 THROUGH 500 AM EDT WED MAY 20...

NW PALM COAST 12.20"
PIERSON 10.17"
UMATILLA 9.24"
DAYTONA BEACH 9.1 WSW 9.06"
ORMOND BEACH 3.5 SE 8.76"
DE LEON SPRINGS 0.4 SE 8.07"
ST. AUGUSTINE SOUTH 2.1 SSW 7.87"
ST. AUGUSTINE SHORES 0.7 ESE 7.65"
SANFORD/ORLANDO 7.10"
DE LAND 5.7 NW 7.06"
HASTING 6.54"
APOPKA 6.23"
OKAHUMPKA 6.21"
DELTONA 2.9 SE 5.71"
NEW SMYRNA BEACH 1.5 E 5.47"
MELBOURNE 8.2 NW 5.27"
PALM SHORES 1.4 W 5.18"
HOMESTEAD AFB 4.17"
LEESBURG MUNI ARPT 3.98"
DOVER 3.74"
BROOKSVILLE 3.68"
VERO BEACH MUNI ARPT 3.37"
FORT PIERCE/ST LUCIE 3.27"
MIAMI 4.1 SE 3.06"

Yowza, that's a lot of rain for Florida!

The low will gradually drift westward through the Gulf of Mexico, but it will take its sweet time and continue to unleash heavy rain on Florida. Here are the forecast totals through the end of this week:

That's another six inches possible on top of up to a foot of rain that has already fallen in Northeast Florida. High pressure over the Mid-Atlantic (what's bringing us the pleasant, dry weather) will steer the low westward, steering clear of us. The low will eventually weaken over the Gulf Southeast States.

--Carrie

Florida Not Living Up To Its Name

Florida is nicknamed "The Sunshine State," but this week it is not living up to that title. Heavy rain is inundating the entire state right now, as a stalled cold front interacts with a developing area of low pressure drifting through the region. So far, widespread 2"-4" have fallen in Florida this week, and here is what Floridians can expect over the next 24 hours alone.

That red bulls eye in Northeast Florida is up to 5.5" of rain possible from today into early Wednesday morning.

And by this weekend, check out the totals this low pressure system will be capable of producing over the next five days:

Wow, that's more than 10" of rain possibly along the Northeast Florida coast!

As the low tracks westward into the Gulf of Mexico, it could become the first named storm of the 2009 Atlantic Hurricane Season, Ana. It would have to develop at least partial tropical characteristics to earn that designation, though, and it may end up being nothing more than a prolific rain-producing low pressure system passing through the Gulf States this week. However, because of at least the slight potential for tropical cyclone development, the National Hurricane Center has been keeping an eye on the system (well, technically the low over the Bahamas is being absorbed into the low over Florida, but they're watching it).

In case you're wondering, here's the full list of names for the 2009 season, which official begins June 1st.

--Carrie

Tuesday Morning Chill On The Way

The cold front that moved through the Commonwealth Sunday left a noticeably cooler, drier airmass in place Monday, and not only here, but also across our region. Check out the low temperatures this morning (click image to enlarge), which dipped into the upper 30's in western Virginia.

The cold front made it into Northern Florida this morning, and as of this post, was halfway through the Sunshine State.

So it's fair to say this was a pretty strong front. Behind that front, high pressure will move into the Mid-Atlantic at the surface, keeping winds light overnight. With the cooler, drier airmass in place, combined with clearing skies, we should have a pretty chilly night Monday into Tuesday morning. Frost Advisories are in effect Tuesday morning from 3-9 a.m. for far western and north-central Virginia, where low temperatures are expected to drop into the mid-30's overnight. A few spots will probably reach the freezing mark, too.
In Central Virginia, we are expecting lows Tuesday morning in the upper 30's and low 40's.

--Carrie

Update On The Tropics

I just got done looking at the latest data, and it still looks like a low pressure will develop off the western coast of Florida early Wednesday.



There will be an upper-level circulation associated with this low so it will not start as a tropical system. In addition, it will be completely cut off from the jet stream (which will be all the way in Canada), so it will have an erratic track.



However, if this low continues to drift into the warm waters of the Gulf Of Mexico, then it could begin to develop more tropical characteristics (i.e. become a sub-tropical or tropical storm). A lot can change in the coming days, but we will continue to monitor this closely because it could become the first named storm of the season...Ana.

Talk About Opposites...

While we are dealing with chilly weather here across the Mid Atlantic, it is a different scenario out West, where they are in the midst of a heat wave!

Weekend Rain Totals

Although rain totals for Richmond and Petersburg were roughly around a half inch, amounts were much more impressive elsewhere. Check out the totals for some of our western communities - Doppler estimates are anywhere from 2 to possibly 5" for Orange, Albemarle and Buckingham counties!

Showers Persist This Morning

Showers and an occasional downpour will be possible this morning. Showers will become more isolated in the afternoon, so today will not be a complete washout. We will then be completely dry in the evening.

Thunderstorms Possible Tonight

There is plenty of energy in the atmosphere to feed the thunderstorms out west...especially in the northeast corner of the state.


Surface-based CAPE

These storms are crawling to the east at around 20 to 25 mph and should affect metro Richmond between midnight and 2 AM.

Although I am not expecting these storms to be severe (i.e. causing damage), you can expect very heavy rain, 40 mph wind gusts, and frequent lightning. The strongest storms will stay north of I-64, where most of the energy resides.

Ana?

This is a loooong way away (i.e. a lot can change), but it is something we are carefully watching. Latest data has been very consistent with developing a low pressure in the Gulf next week.

The water is already very warm:


In addition, the jet stream will migrate to the north, so wind shear will be low:

If this all comes together, we could see a sub-tropical storm develop....the first named storm of the season: Ana.

Rain Totals

Here is a map of Doppler estimates of rainfall over the past 24 hours. The areas shaded in dark green have seen at least 2" of rain!

Severe Storms This Weekend?

We are tracking a storm system that is currently spinning over the Northern Rockies this morning.

A front will pass the area from late Saturday into early Sunday. During this time, we will have plenty of fuel for thunderstorms (heat and humidity).

The key to our severe potential will be jet stream winds. The strongest "lift" and speed shear will stay mainly north and west of the area on Saturday. The majority of severe weather will remain in this area, however, we could still see few strong storms in VA as well.



Jet stream winds will strengthen Saturday night and into early Sunday. This will be the best time where we could see a few severe storms. If this system slows down, then we will have an enhanced threat for severe weather on Sunday (heating from the sun will fuel storms).

Severe Weather Outbreak In Midwest

A massive complex of severe thunderstorms extends from the Great Lakes all the way down to Texas! This squall has caused a lot of damage in the Midwest, including several reports of tornadoes. Here is a map of storm reports from the past 24 hours. The red dots indicate tornado reports, blue are hail reports, and green represent hail reports.



Here is video from some storm chasers who got too close to the storm.





Here is coverage from KMBC, a local TV station in Kansas City.

Heat Burst Event in Oklahoma

Early Wednesday morning in Oklahoma, dying thunderstorms produced a rare (although they can occur several times a year in the Plains as overnight storms weaken) and fascinating event--a "heat burst." Check out the temperatures just before 4 a.m. CDT.

In the red shade, those are low 80-degree temperatures. Surrounding that red bulls-eye, there are 60-degree temperatures and into the low 70's. What could possibly cause a 10-degree localized difference in temperature? Well, let's look at the three hour trend.

This shows that temperatures were dropping in most of the state overnight, but then temperatures rose quickly about 10 degrees or more in that localized spot. I looked at radar, and saw that there were thunderstorms moving east through the state that were rapidly weakening. When a thunderstorm "dies" like this, it can produce a dry downburst of cooler, denser air that is "compressionally warmed" as it descends from high up in the cloud to the ground very quickly. Winds can become very gusty, which they were at the time I took the above snapshots of temperature. Gusts were around 45 mph, but had been up to near 60 mph as that dying thunderstorm moved through Central Oklahoma!

These strong winds are another interesting aspect that make heat burst events so rare. This is because the sinking, warming air must descend faster than the rate at which it is warming. Cooler air is denser than warmer air, and it is that initial density difference that drives the cool, dense air to sink. If it warms, though, it should then be more buoyant than the surrounding air and rise again. But the strong winds descending keep that parcel of air plummeting toward the ground at a rapid pace, so the rapidly warming air slams into the ground with very strong wind gusts.

Heat bursts can occur in the Mid-Atlantic, as well. In fact, there was one on the Eastern Shore of Maryland a few weeks ago. Read about it here.

For a list of other documented heat burst events, click here. And check out another Oklahoma heat burst event that caused temperatures to rise in a matter of minutes at night from 91 degrees to 102 degrees!

--Carrie

Shuttle Atlantis Launch Video & Update

In case you missed the Shuttle Atlantis launch Monday afternoon, you can watch the video here. In fact, NASA has a YouTube page where they post all sorts of interesting video related to ongoing projects, research, expert discussions, etc.


(IMAGE: NASA)
You can get updates on how this Hubble service mission is going here. Here is this morning's update:
"A busy day is ahead for the crew of space shuttle Atlantis as they continue to close in on the Hubble Space Telescope. Today's wake-up music was "Kryptonite" performed by 3 Doors Down. It was played shortly after 5 a.m. EDT for STS-125 Pilot Greg Johnson."
--Carrie

Forecast Good for Shuttle Atlantis Launch Monday

Shuttle Atlantis is ready to launch Monday afternoon at 2:01 p.m. EDT from the Kennedy Space Center at Cape Canaveral, FL. You can watch the launch live online through NASA-TV here.

(IMAGE: NASA)

This eleven-day mission will be NASA’s last trek to the Hubble Space Telescope for service, and the first since 2002. Five spacewalks are planned, when the team of astronauts will add two new science instruments, repair a couple others, and replace other hardware that will extend the already extended life of the telescope. Hubble was originally designed to operate for five years, but the telescope’s batteries have survived more than 18 years, making it the longest-lived low-orbit spacecraft. After the tune-up is complete, Atlantis will act as a “tugboat” of sorts, lifting the telescope to a higher altitude in its Earth orbit and distancing it a bit more from the pull of gravity.

(IMAGE: ScienceBlogs.com)

Atlantis will not make a pit-stop at the International Space Station during this mission, as their sole focus will be to visit and service the Hubble Telescope.
--Carrie