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The Roanoke Valley's two main water supply reservoirs are full and the state of Virginia is almost out of drought (the yellow on the map represents "abnormally dry" on the latest U.S. Drought Monitor ... there were orange and red colors on there for severe to extreme drought a few months ago) and yet Roanoke has STILL not had a single month this year with above-normal rainfall. We were a half-inch down in January, nearly 2 inches down in February, about a third of an inch down in March and, with 3.20 inches, will finish April .41 inch below normal in what seemed like a pretty wet month until the late hit of hot, dry weather (accompanied by a yellow film of pollen on EVERYTHING as the trees exploded into full-leaf mode in the Roanoke Valley in what seemed like a few hours).

The picture is a little skewed because it focuses only on the official rainfall measurement at the Roanoke Regional Airport. Rainfall amounts in many systems have been higher in surrounding areas, and of course much of that drains downward into the soil and the valleys and the reservoirs. Several rains have been widespread rather than just spotty. It's been about timing, too: Several good steady rains at a time of the year when tree roots aren't sucking everything out of the ground. Well, now they will be, so we might need to pick up the pace a bit if we are to keep everything nice and green and the soil moist through the months ahead.

Upcoming this weekend: Likely some thunderstorms, as a pretty strong cold front pushes into the region with some warm, humid air in place. But it appears the rain is focusing west of us the next several days.

This snowy field in Floyd County (for bigger version, click here) isn't a snowy field at all. No, that's hail, two hours after it had fallen at Indian Valley ... so there was even more before this shot was taken by occasional Weather Journal blog commenter "Indian Valley John." If you look closely, you can even see some hail fog at ground level ... moisture condensing in air cooled by the fallen and melting hail. A slow-moving storm combined with a low freezing level (just below 11,000 feet) caused large amounts of mostly small hail to be dumped on a portion of Floyd County Wednesday afternoon. Up to 5 inches of hail accumulated at some spots near Willis and Indian Valley.

So, while some of you didn't even see rain in your back yard (most of the Roanoke Valley), others not far away had quite a stormy show. That will be the pattern the next few days, as spotty showers and storms occur with a flip-flopping front waving across the area and a series of disturbances. More organized action may occur by the weekend.

Click here for a few more photos from Indian Valley John, all taken about 2 hours after the hail storm:

Ankle-deep hail

Hail piled up along a highway

Another roadside hail pile

The weather has been very settled since last week, with days of warm to hot, dry weather. But the weather will become unsettled over the next several days. A cold front has pushed in from the north today and has become stationary to our south. Some showers have developed, mainly just to our north along the Interstate 64 corridor, but a little afternoon heating (highs in the low to mid 70s, rather than mid to upper 80s) could trigger additional showers and even a few thunderstorms elsewhere across the area today. This front's presence near us, the approach of a new cold front from the west this weekend, and several disturbances moving from southwest to northeast into next week will ensure a period of unsettled weather, with showers and storms developing on many days, but few or no periods of widespread rainfall.

We've been losing a couple of degrees on our April heat wave each day ... Roanoke's high was 91 on Saturday, 89 on Sunday, 87 on Monday. We could easily lose two more degrees today, with highs in the mid 80s. But whatever today's high, it will likely be the last extreme high, relative to normal, for many days at least. An approaching cold front will bring a chance of showers and thunderstorms on Wednesday, and because the front will have a hard time pushing east against the high pressure system that has brought us the hot weather, it is expected to stall near our region, leading to several days of shower and thunderstorm chances. This morning's 5-day rainfall potential map from the Hydrometeorological Prediction Center suggests the heaviest rain will be west of our region, but Western Virginia is on the eastern edge of significant rainfall.

As a side note about rainfall ... both Carvins Cove and Spring Hollow Reservoir are now at full pond, according to the Western Virginia Water Authority. (Thanks to reader Wayles Dandridge for pointing this out.)

Using the National Weather Service-Blacksburg data set, Blacksburg set another record high of 85 today, topping the 84 for April 26 set in 1990. (See my last blog entry and comments for the issues concerning the conflicting data sets.) Roanoke's high of 89 today fell 4 degrese short of the 93 set in 1915.

There appears to be two more days of this summer preview left, with highs in the mid 80s to low 90s possible Monday and Tuesday under strong high pressure.  By Wednesday, a cold front begins to make headway into the hot air mass, additional moisture returns. Highs closer to normal in the 70s are expected those days. By late in the week, a cold front will finally push through the heat dome, and more normal temperatures will return to the area.

Roanoke's official high this afternoon was 91 degrees, making this the first 90-degree day in the Star City since April 16, 2002. Lynchburg and Danville also each hit 91 degrees. None of the three sites set records, however, which are in the mid 90s.

The automated weather station at Martinsville was reporting temperatures as high as 97 degrees this afternoon.

The National Weather Service is reporting that Blacksburg has set a record high of 86, topping the previous record for April 25 of 84 set in 1960. This report is somewhat different than the Southeast Regional Climate Center, which lists 88 in 1957 as the record for the date in Blacksburg. I'll see if I can get a clarification on that.

The heat was enough to kick up a few showers and thunderstorms, as moisture in the middle layers and cooler air aloft combined with the surface heating. Sunday is likely to be very similar, both in terms of heat and scattered short-lived afternoon showers and storms.

UPDATED 9:30 AM SATURDAY FOR NEW MAP LINKS

The Storm Prediction Center has Southwest Virginia and nearby parts of the central and southern Appalachians in western Virginia, West Virginia, North Carolina and Tennessee under a "See Text" on Saturday. (Click here for severe risk map) This denotes a region of potential strong to locally severe thunderstorms that doesn't quite warrant a "slight risk," and the "See Text" refers Web visitors to the discussion underneath the map. (Current Day 1 or Saturday discussion linked here) The text notes that southerly winds on the back side of a developing high (the one that is going to bring us several days of summerlike temperatures) may deliver just enough moisture into an air mass that may be just unstable enough (with some cooler air aloft) for a few thunderstorms to develop along the mountain ridges as tempereatures soar close to 90 on Saturday. It is possible that a few of these storms may produce large enough hail ... 3/4 inch or larger ... or put out a wind gust of 58 mph or greater to warrant a severe thunderstorm warning.

Really, this is like many afternoons in July or August when temperatures get hot and the daytime heating, combined with a few other marginal factors, is enough to trigger a few thunderstorms. If you happen to be under one of these storms, it might be momentarily spectacular, but most people will not be under one on Saturday. Don't be surprised to hear a distant rumble of thunder even if it stays sunny and warm where you are. The storm threat for any particular location is very low, and no reason to cancel outdoor plans entirely ... but just enough to keep an ear and eye out for any suddenly developing storms.

"See Text" advisories sometimes go away and sometimes turn into "Slight Risk" zones depending on how things come together.

The atmosphere is expected to become more stable Sunday through Tuesday as high pressure continues to build and the atmosphere warms and stabilizes at all levels, so chances of storms will dwindle from slight to miniscule as the mercury possibly challenges 90 each of those days.

Don't let the chilly start to Friday fool you. Friday will likely be the start of at least 5 straight days of 80-degree-plus weather in Roanoke. We haven't had as many as four straight days in the 80s since Oct. 13 to 16 of last year, and haven't had as many as five since there were 11days at or above 80 from Aug. 29 to Sept. 7. I would place our chances at scraping 90 one day in this warm stretch at about 1 in 4.  Normal highs this time of year are low 70s in Roanoke and mid 60s in Blacksburg, so we could be topping those by 15 degrees or more. With Blacksburg exactly at normal and Roanoke a little more than a degree below normal through the first three weeks of April, this little hot spell will likely make April an above-normal temperature month overall, though much of it was rather cool and damp.

Never mind that the U.S. Drought Monitor shows that Myrtle Beach is out of the drought. Dry winds behind the cold front that pushed thorugh here have fanned a huge wildfire that has burned dozens of homes near the popular coastal tourist destination for Southwest Virginia residents.

We're about to shift out of the mode of posting photos of late April snow (some links posted in the comments of my last entry) to watching how high the mercury can climb. Thursday will be a nice spring day in the upper 60s to mid 70s, but the next four or five days after that are likely to be in the 80s. As high pressure builds in at the surface and aloft, we'll get a setup similar to a summer heat dome going, with stable air aloft inhibiting clouds and precipitation, and bright sunny skies each day to push the temperature up. Various forecasts are currently peaking Roanoke in the mid to upper 80s on Saturday, but I think there's even some chance we could scrape 90. Even if we do, it won't be setting any records. Record high for April 25 is 95 set in 1925, it's 93 for April 26 set in 1915, and it's 95 for April 27 set in 1957. Roanoke's earliest 90-degree day was March 19, set in 1945.

Blacksburg's records for those three dates are 88, 86, and 90, respectively, all set in 1957, so those probably will stand, too. (Blacksburg's records go back to 1952, Roanoke's to 1912).  That must have been a torrid late April in 1957 ... all of Blacksburg's record highs between April 25 and May 1 date to 1957.