Thursday, September 30, 2010

Rain Totals

Here is a rough estimate of the rain totals so far with this storm.

Flooding Picture From Fort Eustis

Flash Flood Watch Continues, Tornado Watch For Some Until 7AM

A long moisture plume stretching from Nicole's remnants in the Atlantic continues to spread heavy rains northward through the Commonwealth early this Thursday morning. The Flash Flood Watch remains in effect through this evening, with average rainfall totals of 2"-4", but with higher totals possible around 5" in spots. Overnight we are already getting multiple reports around central Virginia of flooded intersections and poorly drained areas, especially in urban regions. Do not drive your vehicle over water-covered roads. You cannot tell if the road beneath has washed out. Until daylight, please use extra caution if you must travel, as flooding threats are most dangerous in the dark when you cannot see far enough ahead on the road to tell if it is water-covered.

In addition to the flooding threat, there is also the risk for isolated tornadoes in eastern Virginia overnight and through this morning. A Tornado Watch has already been issued for our southeastern area, including Sussex, James City, and Surry Counties, and the City of Williamsburg until 7 a.m. This watch may need to be extended northward into more of the eastern half of Virginia if the threat continues this morning. There have already been three tornado reports in northeast North Carolina overnight. We're in monitoring the threat overnight and all morning! Stay with CBS6, we'll keep you ahead of the storm.

Wednesday, September 29, 2010

Tropical Storm Nicole

Since my last update, Tropical Depression #16 was upgraded to Tropical Storm Nicole at 11AM Wednesday with maximum sustained winds of 40 mph. Nicole is tracking over western Cuba and will clip southern Florida today. Nicole will lose its tropical characteristics as it approaches North Carolina tomorrow, meaning that we will receive Nicole's remnants in Virginia through Thursday night. The system is still expected to merge with a frontal boundary along the Southeast and lift rapidly northeast early Friday. The Flash Flood Watch remains in effect for nearly the entire Commonwealth, with 2"-4" of rainfall expected by late Thursday as a result of the moisture plume feeding into Virginia from the Atlantic. Isolated higher totals are possible if any embedded thunderstorms occur, especially along and east of I-95.

Flash Flood Watch Tonight-Thursday

A Flash Flood Watch is in effect for nearly the entire Commonwealth for heavy rain expected, mainly tonight through Thursday as Tropical Storm Nicole (just upgraded at 11AM) hurls tropical moisture into the region. Here is the visible satellite image of the storm (the surface center is moving over western Cuba now):
We are already getting our first rounds of rain this Wednesday morning as moisture surges from the Atlantic through the Southeast into Virginia. Periods of heavy rain will be likely off and on the rest of today, so keep your umbrella handy. You can see the cloud-cover expanding into Virginia here:
The prolonged heavy rain event will start overnight and continue most of Thursday as the tropical low pressure system tracks toward Virginia. The low itself will track over Virginia late Thursday into early Friday, ending our rain pre-dawn Friday. Tropical Storm Nicole will rapidly merge with the stalled front along the southeast coastline, which will only enhance moisture transport and heavy rainfall from the Carolinas into Virginia. In Virginia's watch area, 2"-4" is possible through Thursday, with locally lesser and higher amounts possible. Embedded thunderstorms overnight into Thursday would lead to higher local rainfall accumulations. Wind shouldn't be a major concern widespread, as this is a "weak" system wind-wise, with maximum sustained winds right now of 35 mph. In Virginia, we're expecting sustained winds of 10-20 mph in central Virginia, with 20-30 mph sustained winds in the Peninsulas, and 40mph sustained winds in the Bay and Eastern Shore. Flash flooding in heavily paved cities and poorly drained areas will be our main concern overnight through Thursday.

Tuesday, September 28, 2010

Tropical Depression #16 Forms

As expected, Tropical Depression #16 was officially designated this morning for the low we've been watching in the northwest Caribbean south of Cuba. TD 16 is just below Tropical Storm strength, and will likely reach that later today or tomorrow and be named Nicole. This system is expected to track over Cuba and southern Florida tomorrow, then hug along the Southeast US Thursday. Heavy rain is possible in the Commonwealth from late Wednesday through Thursday while this system interacts with the surface boundary that will stall along the coast today. This is the front moving through today associated with the potent low pressure system tracking north of us this morning.

More Rain Coming...From The Tropics

A low pressure system in the Caribbean just south of Cuba is becoming better organized early this Tuesday morning. It could become a Tropical Depression or Storm at any time. The next name on our list this year is Nicole. Regardless of what happens with its intensity, we expect this low to track northeast over the next two days, passing over Cuba and Florida, pushing tropical moisture northeast into the Mid-Atlantic Wednesday and Thursday.
It looks like heavy rain will be possible in the Commonwealth mainly on Thursday as a result of this storm system tracking through our area. It will quickly exit northeast late Thursday, and a strong cold front will sweep through from the northwest Friday bringing our first true taste of Fall for the weekend into early next week.

Monday, September 27, 2010

Slight Risk For Severe Storms

Rounds of welcome rain have been moving through central Virginia overnight, but strong to severe storms will be possible Monday afternoon and tonight. Wind will be the primary threat, but isolated tornadoes could also develop. The strong upper-low pressure storm system responsible for our first significant rainfall since mid-August will lift northward Tuesday, ending our rain and storm chances mid-day. But while ample lift and moisture remain in our region, severe storms are possible. Don't be surprised if you wake up to thunder overnight tonight.
A second storm system will bring more rain late Wednesday and Thursday. This storm is currently in the Caribbean near Cuba, and is expected to track northward through Florida and along the Southeast coastline the next several days, overspreading tropical moisture into Virginia Wednesday and Thursday. You can see the white clouds south of Cuba and east of the Yucatan associated with that broad low pressure system this morning:
This system should result in more much-needed rain in drought-ridden central Virginia.

Sunday, September 26, 2010

Watching The Caribbean

Tropical Depression Matthew continues to dissipate over southern Mexico this Sunday morning, but we will be monitoring the Caribbean south of Cuba over the next several days for a potential low pressure system developing. There is some indication that a new tropical system may organize in this region of the Caribbean by Wednesday, and track toward Florida and along the Southeast U.S. coast later this week. However, this scenario is highly uncertain right now, as the system is currently non-existent. Still, we will be monitoring the region and provide updates on any potential impacts this might have for the Commonwealth by the end of the week.

Friday, September 24, 2010

Record Heat Continues

We set a new record high in Richmond Friday of 96 degrees, breaking the old record for this date of 95 degrees from 1970. This is about 20 degrees above our average high for this time of the year!

Notable hot Late Summer/Fall records:
Hottest Temperature in October: 99 degrees (Oct 6, 1941)
Latest 100 degree day in the year: September 11, 1983

Here's where we stand year-to-date with our hot temperature tally through Sept 24:
100+ degree days: 10 (new record this year...beat 1954 with 9)
95+ degree days: 40 (new record this year...beat 2002 with 35)
90+ degree days: 77 (new record this year...beat 1977 with 70)

Thursday, September 23, 2010

Full Harvest Moon & Jupiter

I shot this photo outside the CBS6 studio at 4 a.m. Thursday of the Full Moon, nicknamed the "Harvest Moon" because it is the full moon nearest to the Autumnal Equinox (this was the first time in nearly 20 years that the Full Moon occurred on the same night of the Autumnal Equinox). To the lower left of the Moon, you can see a bright white light, and that's the planet Jupiter. You can still see the bright planet Jupiter near the Moon the rest of this month.

Wednesday, September 22, 2010

Summer Goes Out With a Bang

Today was the last day of summer and it was a stormy one for much of western Virginia. A weak upper-level disturbance was enough of a trigger for numerous severe thunderstorms to develop in a hot and humid air mass. Several counties reported wind damage and large hail as the storms moved through. The above photo was taken at Keswick Resort near Charlottesville.

Autumnal Equinox & Full Moon Tonight

Tonight is a "special" one, astronomically speaking, because for the first time in nearly 20 years the Full Moon is on the same night as the Autumnal Equinox. In fact, these two moments occur a mere six hours apart from each other. NASA's Dr. Tony Phillips writes, "There hasn't been a comparable coincidence since Sept 23, 1991, when the difference was about 10 hours, and it won't happen again until the year 2029." As a result of these two big events occurring on the same night, tonight's full moon has been dubbed the "Super Harvest Moon." The full moon closest to the Autumnal Equinox is always nicknamed the "Harvest Moon" because farmers rely upon clear skies and the light of the full moon to work past sunset into the night to bring in crops (at least before or without artificial lighting). But astronomers have added the "Super" onto it this year because it is the "ideal" Harvest Moon, occurring at the start of Fall! The Full Moon rises tonight in the east around sunset, and will be overhead at the Autumnal Equinox at 11:09 PM. While you are observing that full moon overnight, you will see a bright white light near it, and that's the planet Jupiter! It's very close to Earth this month.
(A Moon-Jupiter conjunction on Aug. 26, 2010. Credit: Tom Cocchiaro.)
The Autumnal Equinox, or the official start of Fall, is tonight at 11:09 EDT. This is the moment when the Earth's axial tilt is aligned with the Sun, and from our perspective on Earth, the Sun's most direct rays are over the Equator. For the Northern Hemisphere our days become shorter than the nights. The reason why we have seasons is because of that axial tilt I just mentioned. Earth's rotation axis is not perpendicular to its orbital plane, as seen in this diagram:
So as the Earth orbits the Sun in a year, different parts of the Earth will be more "exposed" to the Sun than others, leading to seasons in the Northern and Southern Hemispheres. The tilt of the Earth never changes, but from our perspective on Earth as we move around the Sun, the Sun appears to be higher or lower in our sky through the year...seasons!

Tuesday, September 21, 2010

12th Named Storm of the Season Forms

Tropical Depression #14 strengthened early Tuesday into Tropical Storm Lisa west of the Cape Verde Islands in the east-central Atlantic Ocean. It is just barely at tropical storm strength with maximum sustained winds of 40 mph. Lisa is drifting north at just 5 mph, and will likely never impact the U.S. It is expected to stay in the open Atlantic for the duration of its life. Its track is highly uncertain right now, though, as seen in this ensemble guidance track plot:
There is some indication in extended forecast data that a tropical system may be closer to the US at the end of this month, so we'll be monitoring those trends in the coming days.

Monday, September 20, 2010

Tropical Depression Fourteen Forms

Tropical Depression Fourteen formed this evening in the eastern Atlantic Ocean just west of the Cape Verde Islands. If this depression intensifies, it would become Tropical Storm Lisa.

Saturday, September 18, 2010

River Level On The James

The river level at Westham in Richmond is 3.4 feet. Although this is exceptionally low, it still doesn't make the list of the all-time lowest...yet. Here is the list:

1) 2.00 ft on 09/22/1966
2) 2.94 ft on 10/21/1968
3) 2.94 ft on 10/10/1970
4) 3.00 ft on 09/25/1936
5) 3.00 ft on 09/17/1943
6) 3.12 ft on 09/30/1981

You can find more about river levels at the following links:

Friday, September 17, 2010

Drought Likely Through Christmas

The severe drought conditions plaguing central Virginia right now will likely persist until at least Christmas. There has been no change to the drought conditions over the past week, as indicated by our weekly update map here:

But the big concern is when will this drought end? Because of a strengthening La NiƱa in the equatorial Pacific Ocean, expected rainfall through the end of the year in Virginia will likely not be enough to pull us out of the deep rainfall deficit. As of today, Richmond International Airport is 9.35" below average for our year-to-date precipitation. Most of this deficit is as a result of missing Summer rains, which were held off by persistent high pressure ridges inhibiting storm tracks from reaching us, and also limiting afternoon and evening storm development because excessive heat accelerated drying. July is usually our wettest month of the year, picking up 4.67". This year, we accumulated just 1.19". Our precipitation tally stands at 22.96" this year of liquid precipitation (including the melt-down from winter snow). On average, Richmond has an annual rainfall of 43.91" (1971-2000 normals). If we don't get another drop of rain the rest of this year it would be our second driest year on record. Here's the Top Ten Driest:

1.) 1941 22.91"
2.) 1876 27.65"
3.) 1970 28.29"
4.) 1965 29.76"
5.) 1921 30.59"
6.) 1930 31.26
7.) 1925 31.42"
8.) 1954 31.45"
9.) 2001 31.52"
10.)1877 31.71"

If rainfall is scant through Christmas, it's feasible, if not likely, this will be one of our driest years on record.

You can read a full summary of the drought impacts in our region here. You can also learn more about the long-range drought outlook forecast here.

Wednesday, September 15, 2010

Two Cat 4 Hurricanes At Once

After rapid, unexpected, explosive intensification late Tuesday into early Wednesday, Hurricane Julia reached Category 4 strength this morning, making it the most intense hurricane to ever occur so far to the east in the Atlantic Ocean. Julia is only a little weaker than Hurricane Igor, also at Category 4 strength today. Having two hurricanes of similar, major intensity at the same time is incredibly rare. This situation has only happened once before (on record). September 16, 1926 is the only other time we know of since 1900 that had two Category 4 hurricanes occurring simultaneously in the Atlantic basin (Hurricane #4 and the Great Miami Hurricane). In fact, getting two major (category 3 or stronger, if only briefly) hurricanes at the same time is rare to begin with. It's only happened nine previous times on record:

1933 (Storms #11 & #12)
1950 (Dog & Easy)
1951 (Easy & Fox)
1955 (Hilda & Ione)
1958 (Helene & Ilsa)
1961 (Carla and Debbie)
1964 (Dora &Ethel)
1969 (Camille & Debbie)
1999 (Floyd & Gert).
(Archive data released by the National Hurricane Center)
What is going on in the Atlantic right now is incredibly rare and noteworthy. (It is important, though, to also mention that we didn't have reliable satellite information on storms until after the space age, of course...meaning there may have been hurricanes well into the Atlantic like Julia that were missed or not properly recorded the first half of the 20th century). Both of these powerful hurricanes, Igor & Julia, will remain well away from the U.S. However, Bermuda is poised to receive a direct hit from Igor, which may still be at major hurricane strength when it passes over the tiny Atlantic island this weekend.

Tuesday, September 14, 2010

New Pictures From Lake Chesdin

One of our CBS6 viewers, Cindy Crowder, took these pictures Sunday afternoon from Chesdin Landing on Lake Chesdin, showing us just how low the lake level is right now. By the grass that grew over the Summer, you can see the level has been falling for a while. Cindy says where the grass is now, she used to be able to stand in knee-high water.

Monday, September 13, 2010

Tropics Update Monday Noon

Major Hurricane Igor (image: east of the Leeward Islands) and Tropical Storm Julia (image: far right storm just coming into satellite view) are tracking through the open Atlantic Ocean today, and both storms will likely never impact any landmasses, other than Bermuda. Here is Igor's expected long-range track, which curves over Bermuda this weekend and tracks northeast into the North Atlantic, losing its tropical characteristics next week. The reason why Igor is expected to make this curve northeast is because a trough will sweep through the East Coast Friday and out to sea on Saturday, giving Igor the nudge northeast it needs to avoid any U.S. impacts.
And here's Julia's track, which will also remain in the open Atlantic even farther away from the U.S.:
Tropical Storm Julia could strengthen into a hurricane mid-week.
Hurricane Igor is likely already about at its peak intensity, and should gradually weaken over the week, but remain a major Category 3 or stronger storm while it remains over very warm ocean waters with limited disruptive shear.
A disorganized disturbance in the central Caribbean is also being monitored for potential organization right now.
There is a chance this could organize in the coming days into a tropical system. If it does, the next name on our list is Karl.

Seeing Early Fall Colors?

You may be noticing some trees already showing "Fall" colors (mainly dark red or brown) in central Virginia. This is not directly a result of our Summer winding down, but rather because of the severe drought plaguing central Virginia. The trees on which you are seeing early color are young, recently damaged, or "distressed" (i.e., very dry). In our parking lot at CBS6, I found one such example of a distressed tree:
This tree is relatively young, doesn't get special watering from a sprinkler system (which if it were there, would unhelpfully be in the middle of the parking lot), and it lost some limbs earlier this year during a severe wind event. Therefore, this tree is certainly stressed, and is trying to save itself by pulling nutrients into the core of the tree, thus conserving water, and allowing the leaves to drop early. Going dormant is the tree's self-preservation tactic.

Because of our severe Summer drought, this could delay the onset of healthy tree Fall color a few weeks later than average (see map below for average Fall color peaks). However, distressed trees will "peak" early in the season and drop their leaves.
If warmer than average temperatures continue through the Fall as they did through Spring and Summer, our colors in the Commonwealth could be dulled, too. So if you're in Virginia and you want to see typical color for our state, you'll need to go where the drought is over: southwest Virginia. In central Virginia, our Fall colors may be lack-luster as trees struggle to survive this drought. Here's the latest Drought Monitor:
You can read official Fall foliage reports for Virginia here all season.

Sunday, September 12, 2010

Tropics Update - Sunday 6:15 PM

Igor is a major hurricane in the central Atlantic. It looks very impressive on the satellite imagery this afternoon. The current weather pattern should steer Igor away from the East Coast by the end of next weekend. In fact, almost every computer forecast keeps this storm several hundred miles off the coast. We are also watching Tropical Depression 12 near the Cape Verde Islands and a strong tropical wave in the northern Caribbean. We will bring you more updates through the week...stay tuned!

Thursday, September 9, 2010

La Nina Expected Thru Winter

Cooling of the surface waters of the Equatorial Pacific west of South America continues, and these La Nina conditions are expected to persist through the Northern Hemisphere Winter 2010-2011. Large negative anomalies (cooler than average surface temperatures) started in June, and continue to deepen. In the Fall, Virginia is typically about average for temperatures and drier than normal during a La Nina. That does not bode well for our drought situation right now. So what type of weather typically happens in the U.S. when we have a La Nina Winter setup?
(here's another view of the same information...)
In Virginia, we're right on that borderline of wet versus dry conditions, but there tends to be at least one of the jet streams dipping or tracking right over us, allowing storm tracks to head our way. That may be able to bring us the precipitation we sorely need.

Wednesday, September 8, 2010

Tropical Storm Igor Named

The 9th named storm of the 2010 Atlantic Hurricane season developed today from a tropical wave off the west coast of Africa. Tropical Storm Igor is a weak tropical storm with maximum sustained winds of 40 mph right now. However, strengthening is expected over the next couple of days, when it could become a hurricane by week's end. A subtropical ridge of high pressure in the central Atlantic should steer Igor in a general westward track through the weekend. It is still too soon to say whether Igor will track to the U.S., but we'll be monitoring the steering winds and strength of the system over the next week!