Tuesday, May 31, 2011

Virginia experiences dangerous heat Tuesday

Dangerous heat and unhealthy air quality will affect much of central Virginia Tuesday. High temperatures this afternoon will approach record levels from 1991. The record for today's date at Richmond International Airport is 98 degrees. Here are the expected highs across central Virginia this afternoon:

Afternoon heat index values will range 100-105 degrees in central Virginia, but remember the heat index is a value measured in the shade for what your body senses to be the air temperature. When you're in the sunshine, the added effect of radiational heat on your skin will make it feel even hotter, more like 110 degrees this afternoon. And if you get a sunburn, you'll feel even hotter! Wear that sun protection today, especially between 10AM and 4PM, when the UV Index will be maxed out at 10 (Very High).

In addition to the heat threat, there is also a Code Orange Air Quality Alert for the following counties highlighted on this map:

If you must be outdoors today, here are some crucial heat safety tips to keep in mind:

Pay close attention to your kids and to the elderly, as these age groups are more prone to heat-related illnesses. Do not sit in vehicles for even a few minutes without A/C, as temperatures can skyrocket to 130 degrees within a matter of minutes! Even with the windows cracked, dangerous heat can build up inside the vehicle well above 100 degrees.

If you intend to cool off in the James River today, you are required by law to wear a life jacket (because the river level will remain above 5 ft). Here's the forecast for today:

Memorial Day may have been the "unofficial start of Summer," but the Summer Solstice is not until June 21st at 1:16PM EDT. Stay with CBS 6, we'll keep you ahead of the storm.

Sunday, May 29, 2011

Watching The Tropics

Hurricane season officially starts June 1st and it already looks like we might have something brewing in the tropics. Latest data this morning shows something forming in the western Caribbean by the end of the upcoming workweek. Satellite imagery shows lots of thunderstorm activity in this area, but nothing too organized.

Regardless, wind shear will weaken in the tropics over the next few days, so this cluster could become better organized in the next few days. In fact, most of the global computer forecasts show an area of low pressure forming by the end of the upcoming workweek (indicated by the green circle in the western Caribbean).

Tropical systems typically form in the Gulf of Mexico and Caribbean early in June (see map below), so this is a plausible forecast. We will be watching this very closely over the next several days and will have more updates.

Friday, May 27, 2011

A Severe Thunderstorm Watch is in effect for much of Virginia until this evening

Severe Thunderstorm Watches are in effect until 7-8PM for much of Virginia, including the Richmond and Petersburg metro areas. The Watch in north-central Virginia into D.C. does not expire until 8PM, whereas the rest of central and southern Virginia's Watch expires at 7PM. Strong to severe thunderstorms are developing mid-day Friday in central North Carolina, and are tracking Northeast at 20-25 mph toward south-central Virginia. In anticipation of those storms crossing over into the Commonwealth, these watches were issued shortly after Noon:

Threats from these severe storms will primarily include damaging wind gusts in the 60-70 mph range, and also large hail up to the size of 1.5"-2.0" diameter hail. The severe storms in North Carolina have already produced hail large enough to break windows and dent vehicles! In addition to these threats, any of the thunderstorms this afternoon will also produce frequent lightning and heavy downpours. We'll be providing updates on air and online as needed. Stay with CBS6, we'll keep you ahead of the storm!

Virginia has a Slight Risk for severe thunderstorms Friday

The same storm system that has produced widespread severe weather from the Plains through the Midwest into the Eastern US this week will bring central Virginia an opportunity for severe thunderstorms Friday afternoon and early evening. Once we reach the peak afternoon heating, clusters of strong to potentially severe thunderstorms should track through central Virginia. These storms will be capable of frequent lightning, damaging wind gusts in excess of 60 mph, heavy downpours, and large hail.

Intensity of the storms should heighten between 5-7PM, just as they are passing through the Richmond Metro Area. All thunderstorm activity will exit to the northeast by 9PM. After the locally heavy rainfall, overnight fog will likely develop in central Virginia for early Saturday morning. If you're planning to hit the road early Saturday morning for the long holiday weekend, please be prepared for that and use extra caution.

We will be providing frequent updates on air and online as necessary this afternoon and evening with the severe threat. Stay with CBS 6, we'll keep you ahead of the storm.

Tuesday, May 24, 2011

A Severe Thunderstorm Watch is in effect for nearly all of Virginia

A new Severe Thunderstorm Watch is in effect for all of central Virginia until 8 PM, extending past this morning's watch for southwest Virginia (which remains in effect until 5 PM). Threats from any severe storms this afternoon and early evening will include damaging wind gusts to 70 mph, large hail the size of ping pong balls, and frequent lightning.

The severe threat in Virginia is part of a broad system that will likely produce a significant severe outbreak, particularly in the nation's heartland. Here is the updated severe risk map for the eastern U.S., with a continued rare High Risk over parts of Oklahoma, Kansas, and Texas.

We will be closely monitoring our severe threat this afternoon and evening. Stay with CBS 6, we'll keep you ahead of the storm.

A Severe Thunderstorm Watch is in effect for part of Virginia

A Severe Thunderstorm Watch is in effect until 5 PM for southwest Virginia into Buckingham, Appomattox, and Charlotte Counties. Threats from any severe storms that develop include damaging wind gusts to 70 mph and large hail up to 1.5" in diameter (ping pong size).

Watches may be issued into the rest of central Virginia as the day and evening progresses because we, like a large chunk of the country, are under a slight risk for severe thunderstorms this afternoon and evening. It will be very hot into the upper 80s and low 90s this afternoon, and humid as well. Here's the map with the Slight Risk in yellow, a Moderate Risk in orange, and a rare High Risk in red over the heart of Tornado Alley (Oklahoma and Kansas):

It's the orange and red areas in the Heartland that have the potential for a significant tornado outbreak this afternoon and evening. Unfortunately, this covers some of the same areas that were hard-hit this weekend and yesterday with severe thunderstorms and tornadoes...including devastated Joplin, Missouri from Sunday. Stay with CBS 6, we'll keep you ahead of the storm.

Monday, May 23, 2011

Severe Thunderstorm Watch in Effect Until 11 PM

A severe thunderstorm watch is now in effect for central and southern VA, including all of the Richmond metro area, until 11 PM. Wind gusts to 70 mph and hail to 2" in diameter will be possible with the strongest storms. -Zach

A Severe T-Storm Watch is in effect for part of Virginia

A Severe Thunderstorm Watch is in effect until 6 PM for north-central and parts of west-central Virginia (the counties highlighted in yellow on the map below).

As we enter the warmest part of the day this afternoon, strong to severe thunderstorms are expected to develop in western Virginia, then intensify and track eastward this afternoon and evening. Expect wind gusts to 70 mph and hail the size of ping pong balls (1.5" diameter hail) with the severe thunderstorms. Torrential downpours and frequent lightning are also expected with any of the storms that develop. Follow the latest severe weather updates in our Storm Room this afternoon by clicking here. Stay with CBS6, we'll keep you ahead of the storm.

Virginia has a slight risk for severe t-storms Monday

This week we are in a for a stretch of Summer-like weather with highs in the upper 80s and low 90s. We will have just enough moisture and lift to generate mainly afternoon and evening thunderstorms most days. Monday afternoon and evening there is a Slight Risk for severe thunderstorms for all of Virginia.

I expect thunderstorms to initially develop in western Virginia during the peak afternoon heating, then intensify as they track east-southeast through central Virginia this evening. The threats associated with these storms, which may combine into one squall line, will include damaging wind gusts in excess of 60 mph, large hail an inch in diameter (quarter-size hail), frequent lightning and torrential downpours. Although an isolated tornado cannot be ruled out, that threat appears low today. Thunderstorms are expected to exit east into the Bay after 9PM, with quiet weather overnight.

Here is an hour-by-hour forecast during the time storms are expected in central Virginia.







Be sure to "Like" Chief Meteorologist Zach Daniel's Facebook page by clicking here and also Meteorologist Carrie Rose's Facebook page by clicking here to receive early online updates on our severe threat today and this evening. Stay with CBS 6, we'll keep you ahead of the storm.

Thursday, May 19, 2011

NOAA issues 2011 hurricane forecast

The scientists at the Climate Prediction Center, in conjunction with the National Hurricane Center and NOAA, issued their official 2011 Hurricane Forecast for the Atlantic Basin today. As the CBS 6 Storm Team expected, this is an above-average forecast for the tropical season, which begins June 1 and continues through November 30.

2011 NOAA Forecast:
  • 12-18 Named Storms (39 mph+ sustained winds)
  • 6-10 of those will become Hurricanes (74 mph+ sustained winds)
  • 3-6 of those hurricanes will become Major Hurricanes of Category 3-5 (111 mph+ winds)
An Average Tropical Season:
  • 11 Named Storms
  • 6 of those become Hurricanes
  • 2 become Major Hurricanes of Category 3-5
You can view the full list of storm names for the Atlantic Basin by clicking here.

Watch this video for more details on the forecast and what impacts the tropical season tends to have for us here in Virginia:

The above-average forecast is primarily as a result of the following factors:
  • We continue to be in a "high activity era" of enhanced tropical activity in the Atlantic Basin
  • Sea surface temperatures in the tropical Atlantic where tropical cyclones form are currently two degrees Fahrenheit above-average. This warmer-than-normal water will serve as an excellent fuel source for developing storms.
  • Even though La Nina in the equatorial Pacific is weakening, lower wind shear should linger in the Atlantic into Hurricane Season.
Visit the Red Cross by clicking here to learn how to prepare for a natural disaster like a tropical system. And Stay with CBS6, we'll keep you ahead of the storm.

Wednesday, May 18, 2011

Severe T-Storm Watch in effect until 9PM Wednesday

A Severe Thunderstorm Watch is in effect for part of central Virginia until 9 PM Wednesday for the counties highlighted in yellow on this map:

A set-up similar to the past two days persists in Virginia with a slow-moving upper-level low pressure system pulling in rich Atlantic moisture and providing both lift and spin for storms that can develop this afternoon during the warmest part of the day. With all of these dynamics and the cool air aloft, strong to severe thunderstorms are possible this afternoon and evening. Threats include damaging wind gusts to 70 mph, large hail up to the size of ping pong balls (1.5" diameter), and even an isolated, brief tornado or two. Stay with CBS 6, we'll keep you ahead of the storm.

Tuesday, May 17, 2011

After morning heavy rain, severe storms are possible this afternoon and evening

Heavy rains this morning produced flash flooding in west-central parts of Virginia as a line of showers and storms tracked over the same locations again and again, basically along I-64 from the Richmond Metro up into Albemarle County. Here is a snapshot of some of the rainfall totals through 10AM:

You can see in red on the map below the Flash Flood Warned areas, where at least 1"-2" of rain fell within a few hours this morning:

All the other counties in green remain under a Flash Flood Watch until late tonight. More showers and thunderstorms are expected to develop in central Virginia and track northwest into the Blue Ridge this afternoon and evening, and can produce heavy downpours again. With these two rounds of rain, first this morning and then later today, flooding will continue to be a problem in this part of the state.

Some of the storms that form this afternoon and evening may become severe, capable of damaging wind gusts in excess of 60 mph. A brief, isolated tornado cannot be ruled out, but that chance looks low.

The reason why we have an enhanced threat for severe thunderstorms today is because the center of the upper low-pressure system that has been spinning over the eastern U.S. the past few days is going to drift northeast over the Commonwealth today and tonight, bringing additional lift and dynamics for storms to potentially rotate. As it does so, it is pulling in rich Atlantic moisture from the east and southeast into central Virginia to serve as ample fuel for rain and storm development. Also, we can get topographical lift from a flow like this as the elevation rises from the coast to the mountains. This process is what aided heavy rain and storm development Tuesday morning.

As we get breaks in the clouds mid-day and this afternoon, the atmosphere should warm enough to become unstable with storm initiation occurring. Here's a snapshot of the upper low before sunset today, with scattered showers and thunderstorms ongoing in central Virginia:

I expect storms to rapidly weaken a few hours after sunset, with any severe threat overwith by Midnight. We should remain dry in central Virginia through Wednesday morning, but as the upper low begins tracking just to our northeast, we could receive more showers and a few thunderstorms on the southwest side of the low Wednesday afternoon. Until this low completely exits our region at the end of the week, at least some showers and storms will be possible in central Virginia, which is why we are keeping rain chances in the forecast through Friday. By this weekend, our closed upper low will be replaced with a ridge of high pressure, allowing us a few days to dry out after much-needed rainfall.
--Meteorologist Carrie Rose
Click here to "Like" Carrie on Facebook!

Saturday, May 14, 2011

Severe Thunderstorm Watch Until 11 PM

A Severe Thunderstorm Watch is now in effect until 11 PM for central and southern VA, including all of the Richmond metro area. Winds to 70 mph and hail to 2" in diameter will be possible. -Zach

Friday, May 13, 2011

Severe Thunderstorm Watch Until 11 PM

Severe thunderstorms will be possible in southwest Virginia this evening. An isolated thunderstorm could migrate into central Virginia, however, the air is very stable, so storms should weaken.

Virginia counties included: Bedford, Campbell, Carroll, Charlotte, Craig, Floyd, Franklin, Giles, Halifax, Henry, Montgomery, Patrick, Pittsylvania, Pulaski, Roanoke.

Tuesday, May 10, 2011

Look East Before Sunrise To See A Planet Party

If you're awake about a half-hour before sunrise (which is just a few minutes after 6AM this week), look east toward the dawn and you'll notice a cluster of bright lights just above the horizon (in green) like this:

(Image from Planets 3.0 by Dana Peters http://qcontinuum.org/planets )

That cluster of bright lights is composed of the following planets: Mercury, Venus, Mars and Jupiter less than 10o apart from each other in the sky (from our perspective here on Earth). The planets appear so close together that you could cover them all with your outstretched hand! Dr. Tony Phillips of NASA says, "The best morning is May 11th, when Venus and Jupiter converge to form a tight pair only 1/2o apart. (Now you can hide them using no more than one finger.) Venus and Jupiter are so bright you might think you've witnessed a double supernova beaming through the morning twilight. But, no, it's just the two brightest planets in our own solar system."

If you miss Wednesday morning's show, don't worry, this planet convergence continues through the end of May. For more information on what these planets will be up to in our sky this month, click here.

Watch this NASA video explaining the Planet Party this month:

You can check the exact sunrise time for your location by clicking here.
--Blog by Meteorologist Carrie Rose

Sunday, May 1, 2011

April 2011: A Historic Month For Tornadoes

This is not the type of record you want to break, but April of 2011 will probably end up with more tornadoes than any other month in modern day history. There were 871 tornado reports from last month! These are preliminary numbers, so more than likely the total will drop by one or two hundred.

Regardless, the previous record in April was 267 tornadoes which occurred in 1974. The highest number of of tornadoes for any month was May of 2003 (May is typically the most active month), where there were 558 tornado reports. So more than likely April 2011 will shatter all old tornado records.

Here is a map of all the reports:

The top five states were Alabama (144), Mississippi (115), North Carolina (86), Texas (64) and Tennessee (54). Virginia ended up with 35, which is an unusually high amount. You can find the entire list at the following link:


To put things into perspective, here is the map from May of 2003:

You can see that there significantly less tornadoes in the Mid-Atlantic, though it was a terrible month in the Midwest, especially around Kansas City and Springfield Missouri.