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* We've had 3 phases to our Fay-rain so far: (1) light rain slowly spreading north; (2) broad rain bands moving northeast; (3) bands and clusters of heavy rain training northward over the same areas. We are starting to enter the fourth and final stage, which I will call the "showery upslope" stage. Some of the heavier radar echoes have been moving northwest within the broader area slowly slipping north-northeast. We are seeing the effects of southeast winds blowing uphill as the terrain rises in the western Piedmont up to the Blue Ridge. For the rest of the day and into the evening, expect to see more of a showery kind of rain, with even some breaks in between. Some of the showers -- and possibly even thunderstorms later in the day, especially south and east of Ronaoke -- could put down some heavy rain in a short down on soil that now has its top layer saturated. As a result, a flash flood watch remains in effect through this evening from Lexington south through Bedford, the Roanoke Valley, Franklin County and Martinsville.

* The atmosphere appears to be too stable for a significant severe weather/tornado threat in our area. A tornado watch covers much of central and eastern North Carolina. That could change if we get some sun between rain bands today, but it appears the tornado/gusty thunderstorm threat will be minimal for Southwest Virginia.

* The National Weather Service-Blacksburg's storm total radar composite (click this link, then storm total at left) shows that the heaviest rain has occurred in North Carolina from Greensboro southwest to north of Charlotte, where 6-8 inches is common. 2 to 4 inches appears to be common from Roanoke southward and also in another area south of Wytheville. Elsewhere, 1-2 inches is the norm. Keep in mind this is based on not-always-perfect radar estimates, which appear to pretty accurate overall considering ground reports from earlier this morning.

* So far, I've seen no reports of significant flooding in Virginia. There are several reports of roads flooded and closed in neighboring counties of North Carolina, but I have not seen any for Virginia. Please let me know, by a comment below or an e-mail, if you are aware of a flooded creek or road in Southwest Virginia.

* You may recall that Roanoke needed .66 inch of rain this week to avoid this being the driest August on record. Well, it was like Fay knew exactly how much needed to fall on Tuesday to stop the record ... Roanoke received .67 inch by midnight at its official weather station at the Roanoke Regional Airport. Since then, more than an inch of rain has fallen for a storm total exceeding 2 inches.

UPDATE 9:45 A.M.: A flash flood watch is now in effect for several counties along and east of the Blue Ridge, including Roanoke County, through this evening. Flash flood warnings are also in effect for Henry and Patrick counties, along with several counties in North Carolina. For the latest on watches, warnings and advisories, click on the National Weather Service's Current Events page. I've also added a list of area rain totals as of 8 a.m. in the extended entry at the bottom. END UPDATE

The next two or three hours will bring periods of intense rainfall to the Roanoke Valley and points south and southeast, along the Blue Ridge through Franklin, Floyd, Patrick, Henry and Bedford counties. Rainfall amounts may exceed an inch an hour at times as these patches of heavy rain move northward. Beware of localized stream flooding and ponding on roads ... but overall this surge of heavier rain is a good thing for depleted Smith Mountain Lake and the Blackwater River, where Rocky Mount draws its water. By mid-morning, we may start to see the rain become more showery, but this will introduce a new threat. Scattered severe thunderstorms may develop along a warm front moving northward later today, especially if there is any sunshine to warm temperatures at the surface and destabilize the atmosphere. The Storm Prediction Center has put much of Southwest Virginia under a slight risk of severe weather, (UDPATE 10 AM: The threat has been shifted eastward by SPC and no longer includes Southwest Virginia. Still some chance of storminess, though.) including the possibility of tornadoes, as winds moving different directions on each side of a warm front may create some spin in the atmosphere.

Click here for the latest National Weather Service radar

In the extended entry below is a list of rainfall amounts from the Naitonal Weather Service-Blacksburg's county warning area, as of 8 a.m. As always, feel free to drop a comment to tell everyone how much is in your rain gauge.

Read more »

It appears that we have shifted into the second gear of this rain event. The first began during the day and continued into early evening, involving drizzle and very light rain advancing slowly northward. Now, bands of rain moving northeastward, some with locally heavy downpours, are moving across the area. This radar image from just after 10 p.m. shows one band over the Roanoke area, a break just to the west, and then a second band moving in from the southwest. It appears that more of these bands will move through overnight, each dumping moderate to heavy rain as it goes by. On Wednesday, we may enter a phase where bands are moving due northward as the circulation center gets closer, creating the possibility of "training" or rain and storms moving over the same areas repeatedly, boosting rain totals by a matter of inches in localized areas. Later Wednesday, the passing low may draw in southeast winds that will create a phase of the storm where upslope flow over the mountains is the predominant means of precipitation.

One thing that we'll have to keep an eye on with the bands on Wednesday is whether any sunshine can break through in the gaps between bands, boosting instability. This would create a heightened risk of locally severe thunderstorms with gusty winds and even the possibility of tornadoes. Tropical systems typically spin off tornadoes as they move inland, and Fay has done just that over Florida, Alabama, Georgia and South Carolina. At this time, tornadoes are not expected to be a major risk in Southest Virginia on Wednesday, but it's just something to stuff away in the back of our minds as a possibility to consider if certain conditions develop. The main threat continues to be locally heavy rainfall that could flood streams or roads quickly in the heavier bands on Wednesday.

There's no time to get into details now, but let's also keep Hurricane Gustav in the back of our minds for down the road once Fay gets on by us. Lashing Haiti now, Gustav is projected to enter the open waters of the Gulf of Mexico by the weekend, and may be a threat to the U.S. Gulf Coast next week.

With the exception of some amounts approaching an inch in the highest elevations of Grayson County, rainfall amounts so far this afternoon across Southwest Virginia have generally been a quarter-inch or less. The Roanoke Valley has seen a tenth of an inch or less in slow drizzle and light rain that began about noon. National Weather Service-Blacksburg radar (current scan linked here), however, shows that the colors are changing from the blues representing very light rain to the greens representing steady light to moderate rain. It appears that hours of steady rain are on tap tonight as the circulation center of what used to be Tropical Storm Fay spins in Tennessee, gradually moving northeastward, pulling abundant tropical moisture northward. Later tonight and into Wednesday, heavy bands of rain farther south in Georgia and South Carolina are expected to move into the area, and this is where the real heavy rain threat could begin. A flash flood watch has been issued for a few counties along the Virginia-North Carolina border southward. No flood watch is in effect farther north, but the National Weather Service is projecting 2 to 4 inches of rain to fall up and down the Blue Ridge, including in the Roanoke and New River valleys.

You can follow the latest watches, warnings and rainfall expectation on the National Weather Service's Current Events page.

Everything is in place and on schedule for a much-needed, widespread rainfall starting later today and continuing possibly as late as Thursday. The old circulation center of what was Tropical Storm Fay is still back in Alabama, but it is still drawing moisture from the Gulf of Mexico and it is spreading a shield of moderate to heavy rain across much of east Tennessee, northern Georgia, expanding into the Carolinas. For those of you who follow winter storms, this might seem a little similar, as the bands of precipitation slowly spread northward today. In fact, it is a little like a typical winter weather scenario around here, as Gulf moisture is being pulled over the top of a cooler, drier air mass. Light rain and drizzle has been occurring south of Roanoke, and this should develop here later today. The heavier stuff with the bulk of the system should arrive late this afternoon or tonight and continue at least into Wednesday. Some heavy rain is already occurring near Charlotte, N.C., which may be partly in response to a cold frontal boundary that has sagged southward into that region. We'll have to see if that spreads northward today, which could give us an early shot of heavier rain. As this map from the National Weather Service in Blacksburg shows, widespread amounts of 4 inches or more are expected along the Blue Ridge from Roanoke southward into North Carolina by Thursday evening. Upslope effects of southeast winds drawing Atlantic moisture up the eastern slopes of the mountains, condensing the moisture as it is lifted, will kick in late tonight and Wednesday as winds switch to the southeast with the storm center passing west of us. Localized flooding is still possible in spite of the moderate to severe drought that exists across the area.

The odds are very high and improving by the minute that this will be the large-scale rainfall we desperately need ... though again, hopefully it won't end up being too much of a good thing.

If a continuous rain does fall through the period ... 5 to 8 inches of rain on the eastern slopes [of the Blue Ridge] is not out of the question. Generally speaking ... 2 to 5 inches of rain is possible across the entire area with some localized flooding in stronger rain bands.

-- National Weather Service at Blacksburg, Monday afternoon forecast discussion, referring to Tuesday night to Thursday time period

Southeast U.S. radar at 5 p.m.

With mandatory water restrictions in Rocky Mount and concerns about lowering water levels in Smith Mountain Lake, and moderate to severe drought status over most of Southwest Virginia, this would be a perfect time to see rainfall in inches across the area. And that is exactly what is projected over the next 3 or 4 days. Large areas of rain have formed over states to our south and southwest as the remanants of Tropical Storm Fay, and moisture pulled in off both the Atlantic and Gulf of Mexico by Fay's remnant circulation over south Mississippi, converge. Fay's remnants are expected to drift northeast over the next couple of days, drawing yet more moisture farther and farther north and northeastward over a shallow dome of cooler, drier air near the surface, and up the eastern slopes of Appalachians on southeast winds. The combination of these overrunning and upslope effects promises a solid chance at our best widespread rain in months, and one that is desperately needed.

National Weather Service-Blacksburg radar at 5 p.m.

Already, there are some notable areas of showers and thunderstorms near us this afternoon, particularly over north-central and northwest North Carolina -- a light-to-moderate area of rain resulting directly from Fay's circulation of moisture into the area -- and to the north of Roanoke, resulting from an area of instability sinking south in association with a diffuse cold front. National Weather Service-Blacksburg radar from about 5 p.m. distinctly shows both of these areas. The area to our north is slowly working south and southeast and has some chance of giving us some rain this evening before dissipating. The area to the south has been slowly building north but may need another full day to reach us with significant rain. But it's all good for our dry region: Moisture is building, and several pieces are coming together that are likely to produce meaningful rain.

HPC map depicting risk of excessive rainfall

It's all good if it doesn't get too carried away with itself. Getting several inches of rain in a short time would still have the potential to cause flash flooding in spite of the extremely dry ground. The Hydrometoeorlogical Prediction Center has actually placed much of our region in a slight to moderate risk of excessive rainfall for the period from Tuesday evening through Wednesday evening. Hopefully, the rain will come slow and steady over a couple of days, rather than torrents all at once. Those torrents would certainly help refill streams and reservoirs, but could send some streams and rivers out of their banks. It's the touchy situation we always have when tropical moisture is involved ... our region usually needs a certain amount of tropical-induced rains each year to alleviate droughts and meet annual norms, but most of our most infamous floods have occurred as a result of inland tropical systems. A flood on the scale of November 1985 or even September 2004 is highly unlikely, but don't be surprised to see flood watches or warnings eventually go up in some areas by late Wednesday.

The table is set for a big rain, but it doesn't mean a thing until the water starts falling.

There is a new tropical storm, Gustav, in the Caribbean that could be a factor for the Gulf of Mexico and possibly our area many days out. But first, let's see if the fading Fay will bless us or curse us.

It's been a long time since a 5-day rain forecast map showed anything like this over western Virginia. Taken literally, this would be rainfall of 3-plus inches throughout our region through Friday. But of course, colors on a map and actual rainfall are two very different things.

Here are the steps to getting this kind of rain:
(1) A weak cold front moves through during the next 24 hours.
(2) That front stalls somewhere near us.
(3) The remnants of Fay begins moving northeast, responding to a low pressure trough to the west, spreading moisture into various levels of the atmosphere.
(4) A somewhat cooler, drier wedge of air builds in at the surface from the northeast.
(5) Tropical moisture overrunning that cooler wedge condenses, producing widespread rain. Wednesday appears the most likely day.
(6) A stronger cold front pushes in from the west, helping focus some final rain as it eventually pushes Fay out of the way late this week.

What's left of Tropical Storm Fay is circling a little north of New Orleans in southern Mississippi tonight. In fact, New Orleans is getting some of the heavier rain wrapping around the west and south sides of the old circulation center. There is also abundant moisture streaming in from the Gulf of Mexico into Georgia. As this develops this week, don't get too hung up on where exactly the old center of Fay is. In time, it may become unrecognizeable, and it will be just as important what kind of moisture is being drawn off the Gulf of Mexico and the Atlantic ocean as the system is eventually pulled northeast. Flow over the cooler air mass to the north and upslope flow into the mountains will be as important, if not more so, as where the actual old rainbands of Fay move.

We've got a serious shot at some drought-easing (though not drought-erasing) rains this week. Let's just watch how it does or doesn't come together.

Don't call it "Tropical Storm" any more ... Fay is now a lowly tropical depression. Its circulation center has been inland for hours and its winds, dispersed far from the center, are no higher than 35 mph. It still has a broad shield of rain, though, mostly north of its old circulation center. The most important thing now is to see if it makes its advertised turn northward in the coming week, and whether a passing trough of low pressure to the north and/or a weak cold front can start lifting some of Fay's moisture our way. Fay never became a hurricane, but it hardly mattered, as much of Florida has been inundated by flooding from the pesky system and at least 11 people have died. It goes once again to prove you can't write off any tropical system just because it doesn't carry the moniker "hurricane."

Floridians aren't crying over Fay's demise. And we won't be either if its remnants can cry a small river for us this week.

It seems like we've been talking about Tropical Storm Fay even longer than Barack Obama dragged out his running mate announcement. And, just as that turned out the way a lot of people thought it would for months, the result of Fay may actually end up being exactly what I've been bantering about for more than a week: that we will eventually get at least some decent rain. The latest 5-day precipitation map from the Hydrometeorological Prediction Center shows the bright colors stretching northeastward ever closer to us, which is a change from previous forecast maps that showed us staying in the lighter shades of green, or under a half-inch of rain. Fay, which has killed 11 people in making four separate landfalls in Florida, is still moving west along the Gulf Coast, and is projected to move across southern Alabama and Mississippi to just north of New Orleans before being pulled northward and northeastward by a low-pressure trough moving through the central U.S. As it weakens inland, some of Fay's tropical moisture may stream away from the dying circulation center, so it's possible we could start seeing some rain about mid-week even as the circulation center is still meandering somewhere to our southwest.

Fay formed 8 days ago on Aug. 15 and, originally, we thought it might be a factor in our weather as early as the middle of this past week. Now, it could be a full week later. We'll see. I think the waterloogged folks in Florida are just ready to see Fay quit strutting her many hours upon their stage, and we'd like to see a little rain before Fay diminishes.

Having thoroughly waterlogged most of Florida's peninsula, Tropical Storm Fay is now soaking Florida's panhandle

The circulation center of Tropical Storm Fay is over the Gulf of Mexico again, just a few miles south of the Florida coast, as it continues its trudge west. The warm Gulf waters may help feed Fay enough to keep it at tropical storm strength through much of Saturday, but ultimately this system is likely to end up inland over Alabama and Mississippi and weaken to a depression. It's still up in the air whether we'll get any appreciable rain out of Fay next week, though an increase of moisture, at least, does appear likely. Many forecast models show the remnant circulation of Fay wandering around like a drunken fool over the Deep South for several days next week.

Meanwhile ... another beautifully sunny, not-hot day in Roanoke, with our high temperature hitting exactly normal, 85 degrees. It's too bad that, to get needed rain, we have to sacrifice these wonderfully not-humid days we've been having.