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After three days of cool, damp weather from a persistent (somebody got on to me for saying pesky, though it may fit by now) low pressure system wandering around aimlessly along the coast, maybe today will finally offer some longer breaks of sun as the low moves farther away. This low has been frustrating by keeping dank, drizzly, showery weather in place while not producing enough rain to really do anything for the drought.

Thursday and Friday look dry and warmer, but we'll just have to see how fast the wedge gets broken as to whether today will be any different than the last three have been.

The persistent upper-level low and its surface reflection are slowly moving southeast away from us, and the effects from the system will gradually diminish overnight into Tuesday. Still, the northeast wind whirling around it will push Atlantic moisture against the Blue Ridge overnight, and there could be some showers or light drizzle, which could even hang onto into the morning hours on Tuesday. Amounts will be likely be light, as the bulk of moisture, atmospheric wind shear and instability will be drifting farther south.

Rain has been moving into the Roanoke Valley area from an unusual direction tonight ... from the east and northeast. It's because the center of the upper-level low has shifted southeast of the area, and the spin around it is bringing in the moisture. Expect to see showers and some storms moving in from a similar direction at times overnight into Monday, though showers should slowly dwindle as time goes along. A few showers might linger into early Tuesday before the low moves far enough east for its effects to drift away.

Whether or not we can add to the .64 inch of rain we got in Roanoke from showers and storms the last 24 hours (similar amounts across the area) depends on whether the upper-level low, as it moves east and slightly south of the area, can throw back enough moisture for a rain band to develop in our area overnight and early Monday. Right now, it appears the heaviest rain will occur just northeast of the area, but these sluggish upper-level lows often wobble and whirl a bit, so being off a few miles could make a major difference in the forecast.

Latest National Weather Service-Blacksburg radar

By the way ... severe weather reports from eastern Virginia and eastern North Carolina have included a few tornado reports today.

The Storm Prediction Center has put out a "mesoscale discussion" for Southwest Virginia, extending south into the Carolinas, for the potential of localized severe weather this evening. A line of moderate to heavy showers and storms pressing eastward ahead of a cold front may encounter enough atmospheric shear -- winds changing direction with height -- for enough spin to develop to kick out some brief severe-level wind gusts in a few isolated areas. The Storm Prediction Center even suggests that "a brief tornado" could be possible.

Latest National Weather Service-Blacksburg radar

Latest warnings and advisories from National Weather Service-Blacksburg

A band of rain is moving across Tennessee and Kentucky overnight ahead of a slow-moving low-pressure system and cold front, and should arrive in western Virginia in some form during this afternoon or evening, a little faster than earlier forecasts. The Storm Prediction Center even thinks there may be enough daytime heating, leading to instability, plus enough winds aloft for a small chance of severe-level thunderstorm winds (58 mph or greater) and hail (3/4 inch or more). The 5 percent threat on the map indicates a 5 percent chance that such winds or hail will occur within 30 miles of any given location. It's looking more like half-inch type rain rather than widespread rains of an inch or more, but the showers could linger well into Sunday.

Friday will be a warm day, likely in the low 80s in the Roanoke Valley. Enjoy it, as a rainy period could be on the way. One interpretation of what could happen is shown in the inset map (bigger version here) , which is the 5-day rainfall forecast from the Hydrometeorological Prediction Center. As of Thursday night, this is the official interpretation, based on a low-pressure system poking eastward directly at us against resistant high pressure the next 3-5 days. Computer models have struggled to pinpoint how this system will move. A much more northerly track would leave us in more of a showery regime while a more southerly track would provide lighter rain and cooler weather. There's time later to refine this forecast, but suffice it to say after what could be a decent Saturday, there will be a threat of rain, needed as it may be.

I neglected to mention that Blacksburg's low of 24 on Wednesday morning set a new record, breaking the old April 16 record of 25 set in 1963.

There will be no record cold this afternoon, as highs soar into the 70s. We might see 80s on Friday.

Roanoke's temperature at 7 a.m. was 31 degrees, meaning that the city officially experienced a freeze. The average last spring freeze from 1948 to 2007 was April 12, so this would only be 4 days later than average, provided there is not another freeze later in the spring. The latest date on record for a last freeze was May 11 in 1966, though it dropped to 33 on May 22, 2003, missing a freeze 11 days later by 1 degree. The earliest date for a last spring freeze was March 18 in 1978. The last spring freeze was very early that year even though it followed an extremely cold winter.

Temperatures almost everywhere else in Southwest Virginia were below freezing for a few hours this morning. There is the potential for damage to anything that is budding or blooming, but that seems to be much less than last year, since our March wasn't as warm.

A few areas may get to freezing again Thursday morning, though the overall trend the next several days will be for much warmer weather.

Roanoke is still sitting at 52 degrees at 10 p.m. The dew point is low, 18 degrees, so there is plenty of room for the temperature to fall. It will have to do so hurriedly in the after-midnight hours to get us to freezing. It can do it, but I would not be surprised if the urban areas of Roanoke escape with temperatures just above freezing. Still, a close enough call to get in some sensitive plants. We'll see how it pans out.

Most outlying areas will drop below freezing by Wednesday morning, the second in a row for many locations. A freeze warning is in effect for most counties from Roanoke south and east. The counties north and west of Roanoke will get to freezing, too, but their growing season is not far enough long to warrant a freeze warning, according to the National Weather Service.

Click here for current temperatures at stations across the area