Thursday, September 29, 2011

October Opens Colder

A major change in the jet stream Friday night into the weekend will allow a chunk of chilly Canadian air to move into our area.

This will produce highs in the upper 50s and lower 60s. Lows by Sunday morning will drop to the upper 30s and lower 40s.

This pattern will modify next week, and temps will return to normal levels.

Wednesday, September 28, 2011

Strong to severe thunderstorms are expected Wednesday

After receiving torrential downpours at times over the past week (1.57" on Tuesday alone!), we're still not done with the stormy weather while the big, closed low pressure system responsible for the rain here spins over the south-central Great Lakes region. The surface cold front linked to that low is in western Virginia Wednesday morning, and will slowly move through central Virginia by late tonight, allowing drier air to begin moving into the region. But a second, stronger surface cold front will rush through on Friday afternoon, bringing an end at last to our muggy, wet, warmer-than-average weather pattern that has held Virginia in its grip for more than a week. Recent rainfall, when added to the remnants of Tropical Storm Lee earlier this month, pushed us into the Top 10 wettest Septembers on record at Richmond International Airport, and it's still raining there as of this story posting.

This afternoon during the warmest, most unstable part of the day, strong to severe thunderstorms are possible, capable of damaging straight line wind gusts in excess of 60 mph, large hail, and also a couple brief tornadoes, if storms can rotate. Here's the slight risk map:

The greatest threat is in this region because it will be just east of the approaching cold front, where the atmosphere will be warm, humid, and unstable. The cold front will provide additional forcing for strong to severe storms to develop ahead of it. Stay weather aware this afternoon. And stay with CBS6, we'll keep you ahead of the storm!
--Meteorologist Carrie Rose

Monday, September 26, 2011

This September is one of the wettest on record for Richmond

Three systems this month have made this September one for the record books! As a result of rainfall from Hurricane Irene, the remnants of Tropical Storm Lee, and recent days of rainfall resulting from a cut-off, closed low pressure system to our northwest and an Atlantic high to our east funneling in rich moisture day after day...Richmond International Airport has now recorded enough rainfall to rank in the Top 10 Wettest Septembers on the book!

Quite a chunk (anywhere from 10% to 40% historically) of our September rainfall can be attributed to tropical systems (ranging from full-fledged hurricanes like Irene to merely the remnants of a system that once was tropical).

Several tropical systems affected Virginia in 1999, which contributed to our wettest September on record. Here are the tracks of those that passed through or came close to Virginia with rainfall in 1999:

You'll recognize some of the other years, like 2003, in the Top 10 (resulting from the Isabel bump in rainfall, which was similar to this year's Irene totals):

And 2006 is another year Virginians remember well because of Ernesto's impressive rainfall over central Virginia:

The closed low pressure system currently still stuck spinning around Chicago, IL will finally receive a kick from the upper-level jet stream by mid-week, allowing it to migrate eastward. Its trailing surface cold front will also sweep through central Virginia Wednesday, ending an entire week of muggy, cloudy, wet weather.
Stay with CBS6, we'll keep you ahead of the storm.
--Meteorologist Carrie Rose

Friday, September 23, 2011

Stagnant Weather Pattern

The primary jet stream remains in the northwestern United States into southern Canada. This is separating the chilly air way up to the north and mild/warm air over much of the lower 48 states.

A storm system has been cut off from the main jet stream, and is located near Chicago. There is a cool pool of air and frequent showers with it. The combination of having warm air surrounding the storm and its location away from the main jet stream is keeping it from moving.

Over the next few days, this storm will just slowly drift through the Midwest and Great Lakes.

With that storm stuck, our area will continue under the influence of southerly winds, warm temps and moderate humidity. The moisture and humidity in place will allow for occasional storms with heavy downpours in spots.

This overall pattern is slated to change during next week, allowing more seasonable temperatures and humidity levels to return to the area by mid and late week.

Autumn Has Begun

Wednesday, September 21, 2011

Odds Makers Favor a Pacific Landing of the NASA Satellite

The top bookie in Ireland, Paddy Power, has opened a book on where the NASA satellite UARS will land when it comes blazing into our atmosphere and crashing to earth late Friday. So far, it appears the greatest odds, not surprising, are for a landing in the vast Pacific Ocean. Here are the odds for the landing of the satellite in various areas around the globe, proof that just about anything can be gambled on:

First ocean landing to be reported:

8/11 Pacific

2/1 Atlantic

6/1 Indian

10/1 Arctic

10/1 Southern

First continent landing to be reported:

9/4 Africa

11/4 South America

3/1 Asia

3/1 North America

6/1 Australia

8/1 Europe

16/1 Antarctica

66/1 Part of the satellite to land on Ireland (Must be confirmed by NASA)


Saturday, September 17, 2011

There was another aftershock Friday afternoon. It occurred at 12:17 pm, and was a magnitude 2.1

Location 37.937°N, 77.987°W
Depth 2.9 miles

6 miles south Louisa & Mineral
16 miles northeast of Columbia
19 miles east of Lake Monticello
40 miles northwest of Richmond
86 miles southwest of Washington, DC

Source: Southeast U.S. Seismic Network

Friday, September 16, 2011

Perfect pairing of the Moon and Jupiter this Friday morning!

The Moon and Jupiter are "hanging out" often lately in the night sky, and this Friday morning, they're perfectly paired closer to each other than most mornings so far this week. Visibility is great across the majority of central Virginia because of clearing skies overnight behind yesterday's strong cold front. If you can before sunrise at 6:52 a.m., look for the Moon and the bright, steady light just to its left. That light is the planet Jupiter!

Here is the sky-map looking Southwest from Richmond of the pairing shortly after 6:15, when I took the video below.

And here's that video I shot at the same time from outside the CBS 6 studios on West Broad Street:

If you missed this viewing opportunity this morning, don't worry, there will be other opportunities to see the two clearly in the night sky over the next week (just not this weekend because of cloud-cover). Learn more about this celestial pairing by clicking here.
--Meteorologist Carrie Rose

Thursday, September 15, 2011

First Fall cold front arrives today

A seasonably strong Fall cold front arrives in central Virginia today. As of this update, the front is already moving through the Valley of western Virginia, with dense fog and light rain, as well as cooler temperatures moving in behind the front. Here is the surface observation picture as the cold front is just moving into the Valley:

Temperatures to our northwest are already in the 40s and 50s this morning behind the front, and that's where we'll be Friday morning!

As for today, though, the rest of us in Virginia will see the increasing cloud-cover from the west through the first half of the day, with the front clearing the state to the southeast by sunset. Expect scattered showers and thunderstorms along and behind the front this afternoon and evening in most of central Virginia, with overcast skies and cooler temperatures. High temperatures Friday and Saturday will remain cooler-than-normal for mid-September in the 60s (average highs for those dates: 81 degrees). As for morning low temperatures, we'll be noticeably cooler in the 40s and low 50s, so it's safe to turn off the A/C and open the windows! A word of caution, though...mold spores are an issue right now after recent heavy rainfall, and if you have an allergic reaction to mold, you don't want to open all the windows and let the mold spores indoors. In addition, it's ragweed season, and if you're allergic to that, keep the windows closed! If you do open windows through the weekend with cooler temperatures, then you WILL need to keep running that A/C to filter your in-house air and remove the invading allergens.

Nevertheless! Enjoy the first taste of Fall through this weekend!
--Meteorologist Carrie Rose

Wednesday, September 14, 2011

Did You See Jupiter Last Night?

If not, don't worry, you can see it again tonight and for many nights over the next few months. More often than not, Jupiter is one of the brightest objects in the sky, and it's current magnitude of -2.7 makes it the brightest object in the Virginia night sky other than the moon. Jupiter will appear as a bright star to the naked eye, but a strong pair of binoculars or a backyard telescope will reveal the yellowish sphere and several of Jupiter's largest moons. To find the planet, look to the ENE after 9 PM. It will rise higher in the sky throughout the evening and overnight hours. Check it out! -Zach

Tuesday, September 13, 2011

Tropics Update: More Activity Next Week?

We had a rush of tropical activity leading up to the peak of hurricane season on Sept. 10th, but it has been pretty quiet ever since, with only the anemic Maria floundering in the western Atlantic. The medium range models continue to suggest we'll see a couple of systems try to develop next week, and given the proximity to the peak of the season and several disturbances coming off the west African coast, this seems reasonable. Below is a plot of tropical storm and hurricane frequency throughout the hurricane season, and you can see we're still very much in the meat of the peak time for tropical activity. Above is a plot of tropical cyclone origin during the September 11-20 ten-day time period which we are in right now, and over the years we've seen development in nearly all areas of the Atlantic Basin. Enjoy the lull while we have it! -Zach

Sunday, September 11, 2011

Coolest Weather Since May

A major pattern change later this week will allow highs in the 60s and overnight lows in the lower 50s (40s in the outlying areas). We haven't seen weather this cool since early/mid May.

Friday, September 9, 2011

Lee Drops Highest Rain Totals on Virginia

The remnant moisture of Tropical Storm Lee dumped torrential rainfall over nearly two dozen states over the past week. While other regions have seen greater problems due to flooded rivers, no other state experienced greater rainfall totals than Virginia. It's still raining up in Pennsylvania at the time of this post, so the order of these might change, but as it stands now, Colonial Beach received more rainfall than any other community. We'll fortunately have much drier weather this weekend into the first half of next week. -Zach

A week of heavy rain

The remnants of Tropical Storm Lee have kept frequent showers and storms in the area over the past few days. Some areas have received over 10" of rain just since Tuesday morning.

When you add this to the rain Irene brought the other weekend, area totals have exceeded 10" in many areas with a few isolated spots near 20" east of I-95.

Here is a map of total rainfall through Thursday morning:

Thursday, September 8, 2011

Dense fog descends Thursday morning

After torrential downpours over the past two days, dense fog has descended upon all of central Virginia Thursday morning. Visibilities this morning are being reduced in places to a half-mile or worse. Please use extra caution commuting this morning, as visibility can suddenly plummet. Allow extra distance between you and surrounding vehicles, slow down, and use your low-beam headlights, even though we are past sunrise. Fog should begin to mix out by mid-morning.

Here are some of the pictures from this morning's dense fog around the Richmond metro area.
Dominion Cam in Downtown Richmond (pointed SW toward the James River):

WTVR CBS 6 Rooftop Cam (pointed east along West Broad Street toward the Science Museum):

Richmond Zoo Camera:

So how much rain have we received the last couple of days? Record rainfall for Richmond International Airport!

And here's a radar-estimated map of central Virginia rainfall the past two days:

Stay with CBS 6, we'll keep you ahead of the storm.
--Meteorologist Carrie Rose

Wednesday, September 7, 2011

Tropics Update: Maria Forms and Nate Developing

The tropics are teeming with activity today, and right on schedule, as the peak of hurricane season arrives this weekend. Hurricane Katia continues to move northwestward, but all models are in very good agreement of a northerly and then northeasterly turn over the next 24 to 48 hours. The main threat to the U.S. will continue to be large waves and dangerous rip tides. Tropical Storm Maria formed this morning in the central Atlantic, and is expected to be slow to strengthen as it heads west-northwestward over the next several days. Here's the latest official track from the National Hurricane Center (NHC):

The system is expected to be at roughly 70 degrees west and 23 degrees north and on a northwesterly track on Monday morning. An upper-level trough is depicted by some of the medium range models to be in place which would help to erode the subtropical ridge and impart a more northerly turn to Maria by the middle of next week. There is a quick shift, however, to more of a ridge across the eastern U.S. later in the week, which could be more favorable for an East Coast landfall. Needless to say, Maria will be in interesting storm to track over the next week, as much could change in the eventual course. Another system is in the developing stage in the Gulf of Mexico. Here's the latest spaghetti plot of model guidance for this disturbance:

This disturbance is not even a tropical depression at the time of this blog entry, but given the intensity forecast below, there's the likelihood of this becoming Tropical Depression Fifteen and then Tropical Storm Nate.

I'll continue to track these systems and bring you updates over the next several days. -Zach

Monday, September 5, 2011

Heavy rain likely over the next several days

Heavy rainfall is likely over the next several days in central Virginia, and in much of the Eastern U.S., as a result of an upper trough swinging out of the Upper Midwest and pulling in the remnants of Tropical Storm Lee from the Gulf Coast states. Widespread rainfall totals of 1"-3" are likely over the next several days, with higher totals up to 6"-10" in some locations.
Flash Flood Watches extend from the Canadian border in the Northeast all the way through Virginia and down to the Gulf Coast.

Our heaviest rainfall should occur Tuesday afternoon, overnight, and through Wednesday, when we have our Flash Flood Watch in effect for parts of west, southwest, and north-central Virginia.

Stay with CBS 6, we'll keep you ahead of the storm.
--Meteorologist Carrie Rose

Thursday, September 1, 2011

Third-biggest aftershock rattles Virginia Thursday morning

The third-biggest aftershock since "the big one" a week ago Tuesday woke many Virginians up a little early Thursday, September 1 at 5:09 AM EDT as a magnitude 3.4 earthquake centered slightly northeast of the town of Cuckoo, south of Mineral, occurred. This aftershock has been reviewed by a seismologist, and you can read their full report by clicking here.

USGS Topographic Map, Resolution: 16.0 meters/pixel

Here is the ranking now of our earthquake and the biggest aftershocks since last Tuesday:

This morning's magnitude 3.4 ties the aftershock from August 24th, less than 24 hours after the initial 5.8 earthquake. There have been an official total of 22 aftershocks in the Central Virginia Seismic Zone since "the big one." As of this blog posting, people are reporting into the USGS feeling this morning's aftershock as far north as Baltimore and into southern Virginia from around Lynchburg to Chesapeake.

More aftershocks are likely in the coming weeks, but are not likely to surpass the magnitude of the first earthquake, 5.8.
Stay with CBS 6, we'll keep you ahead of the storm.
--Meteorologist Carrie Rose