UPDATE 8 AM, 7/17: Tropical heat builds into midweek; desert heat stays west, helps push through a cold front by late week
UPDATE 8 AM, 7/17: In general, a repeat of Monday on this Tuesday — perhaps a bit hotter (mid 90s for Roanoke, maybe upper 90s Southside, upper 80s-near 90 New Rive Valley) and fewer afternoon showers and storms with weak downsloping westerly surface winds heating and drying things up a bit. A cold front approaching Wednesday and Thursday will increase the chance of storms again before turning it cooler for late week. END UPDATE
There are two kinds of hot spells we get in Virginia. One comes from the tropics; the other comes from the desert. Two and a half weeks ago, an air mass built over much of the central and eastern U.S. from the Desert Southwest, intensifying over the Plains and spreading eastward. That eventually gave Roanoke 12 straight days of 90-plus temperatures, including 10 97-plus and 4 100-plus. Heat is again building in the early to middle 
part of this week, but it is the other kind, from the tropics. High pressure over the western Atlantic — what we often call a “Bermuda high” — has been pumping in southerly to southeasterly winds, bringing moisture off the Gulf and Atlantic Ocean. While the surface winds may actually turn westerly with a center of the high located to our south in the Southeast U.S., the tropical humidity has already been laid down, and the heat will build into that. This kind of hot spell usually doesn’t produce widespread 100-degree temperatures — a couple of such readings can’t be ruled out, especially in Central and Southside Virginia (map at left is NOAA projection for highs Tuesday)– but it does produce humid conditions and lots highs in the low to mid 90s over most locations from Roanoke eastward, and mid-upper 80s to the west. So while the actual temperature probably won’t challenge the hottest days of the recent extreme heat wave, the feeling outside may be similar, or a little worse at times, because of dew points in the upper 60s to low 70s. With the heat and humidity will come daily chances of showers and thunderstorms, the kind that dump an inch or more of rain in one spot and sprinkles or nothing a mile or two away.
The good news for folks who don’t like the heat (most of you, according to my feedback — there are some exceptions, though) is that it appears very unlikely that the next round of “desert heat” spreading into the central and northern Plains with triple-digit temperatures this week will spread eastward to our region, at least through the next 7 days or so. In fact, the clockwise spin around that “heat dome” high pressure will help push a decent cold front through from the north by late in the week, perhaps Thursday or early Friday. That front will knock the top off this hot spell, likely driving high temperatures back into the upper 70s/lower 80s by the coming weekend. The front pushing into the heat and humidity will raise the risk of storms sometime in the Wednesday-Friday time frame, with severe weather always a possibility in such a scenario.
July 15, 2012 - 9:27 PM
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Yes! Great forecast, cold front just in time for the weekend! That means we will have great weather to play in at the Castle Rock Member Guest, kind of a home coming for me since that is the one time of the year I get to return and play my old haunt, LOL. Even better to get out of Central Virginia and get some of that refreshing NRV air! This is gonna be a treat! Hopefully that 100 degree heat will stay away the rest of the summer!
Tina B – yes, it looks like the storm cell got hung up around the Doppler and we got the rain yesterday – sorry about that Doug. Nice breeze out there early this morning and with the soil wet, it made for a good morning to pull some weeds.
Back from SOBX (Atlantic Beach area) – other than the heavy rain on the drive Wednesday through the Raleigh, the weather was pretty respectable during the day – Friday was overcast and moody but cleared as day progressed and we were able to kayak on the sound that late afternoon. Saturday was an awesome all-day-on-the-beach day. Nurse Shannon – hope you have had good weather at your beach. Beach weather there seems so different – their normal forecast is 30% rain/t-storms nearly everyday but the day usually turns out great. Do tides and prevailing winds influence that?
Storms have moved through Washington County this am. Pretty intense rain here in Abingdon. My garden was still too wet to till yesterday and my late beans and corn are very weedy. Oh to be a human being and never be completely satisfied. I am thankful for the rain and my pastures have recovered nicely. I was actually looking to move my cattle due to the dry conditions but that is not necessary now. Second cutting of hay will be short but it still will happen. I do hope all will get a rain this week. We do not mean to hog it by any means.
The Roanoke Valley is bullseye for storms today. Severe thunderstorm warning until 5 p.m. Came home just in time for thunder, lightning and some rain.
52 mph peak wind gust in storm today at Roanoke Regional Airport. A report of power lines blown down not far northwest, on Nover Avenue near Peters Creek Road.
It poured rain where I was delivering on Troutland Avenue, NW about 4 PM. It poured at Melrose Post Office. There were signs that it poured everywhere on my way home north of Brandon Avenue. Even the parking lot at Promenade Plaza (across Electric Road from North Cross School) got some rain. But you all can guess where it did NOT rain. Nancy said we had plenty of thunder, just to get the dog breathing hard. But alas, it was full of sound and fury, signifying no rain.
Wow – I never noticed anything here in BBurg unless it sneaked by when I was at the grocery store. Was surprised to see your storm remarks Kevin and checked the VT Airport history online and sure enough, they report a t-storm in the area around 630 and again at 715. I was outside walking around 7 and it was overcast but no thunder. Sun poking out now.
Storm just went through – some thunder and lightning and a total of “0.11″ inches of rain.
I got about 2/10 in quick hitting shower in southern Roanoke County. Main part of storm went just east of me on other side of US 220 corridor.
My brother in Vinton reported no appreciable rain at his house. No rain here at the Chapel this afternoon. The morning rain ensured that I would not till the garden. Sounds as if tomorrow will be dry but then the cold front will bring more rain. Maybe everyone will get a decent rain before the weekend. If not, we may have to go to Doug’s and do a rain dance. He is in the dry slot now.
About .40″ here in Franklin Co near Windy Gap. Saw your tweet Kevin on the side here about trees down on 116/122 and I’m not surprised. This area got a good bit of tree damage from the derecho and the limbs/trees that were weakened then I’m sure will be quick to come down with a good gust.
Measured 1 inch of rain in under 20 minutes from a powerful thunderstorm at 6:30pm where I live near Shawsville. Wind gusts were strong enough to break numerous small branches from trees. Very impressive cloud to ground lightning. As dark as the sky got, part of the sky to the northeast remained clear and blue during the entire storm. It was a fun storm to watch!
Thanks for thinking of me, Michael. But if only one of us can have rain, I am glad that it is you. Your livelihood depends on it.
I am surging ahead now in the race for Mayor of Brownsville, and I have not even had to run any political ads, negative or of questionable truth or otherwise. If I don’t get any substantial rain by Saturday, I am declaring myself Mayor. According to Robin Reed and friends (plus Jeff H. on Fox 21/27), the best rain chances locally are Thursday and Friday.
Has wd dropped off the face of the planet? I hope that he and his are OK.
Speaking of areas that have not had rain, Kevin have you looked at what has been happening in SW Missouri, southern ILL., western KY, western Tenn. and most of your former home state of Arkansas? Big drought. I think that a new drought monitor gets issued tomorrow, although they may not post it until Wed. or Thursday.
One area of the nation that is doing just fine, thank you, for rainfall and its pond and lake levels is southern New England. It was great to see green lawns and full ponds and lakes. They have been having a nice first half of summer after a wet April and May, I was told.
Looks like others got dibs again yesterday. Not a drop of rain here. Rained 1/2 a mile down the road but none here. David Gravell…I saw that storm in my way home from C’burg, off in the distance! It did look impressive!
I’m glad the HPC has us getting 1.50″ of rain the next 5 days because the CPC has us going hot and dry in the 8-14 day span. We’ll need that extra moisture to stay green and not be like most of the country. Doug: We have to mow grass after 4 days, since we had so much rain last week. Sorry you got elected as Mayor of Brownsville again.
http://www.cpc.ncep.noaa.gov/products/predictions/814day/814prcp.new.gif
The drought across much of the U.S. covers the widest area since 1956, according to a NOAA report.
http://www.freep.com/article/20120717/NEWS07/207170375/U-S-drought-widest-since-1956-report-shows
http://in.reuters.com/article/2012/07/17/us-usa-crop-ratings-idINBRE86G00L20120717
Rick: That HPC map is probably too smoothed out again for the area as a whole. 1.50 over 5 days likely translates into 3 inches for a few spots, most get half an inch or less and some get sprinkles or nothing.
Concern for us long-term is whether that heat dome centered in the Northern Plains grows back over us beyond the late week cooler push. If it does, another run of triple-digit heat would be possible. Keep it northwest, and we’ll keep alternating hot periods and cold fronts.
That heat dome can just keep its distance as far as I am concerned!
Doug: The next Drought Monitor is posted by the CPC at 10am EST on Thursday and is based on rainfall up to 8am today, Tuesday.
My grandmother always said one extreme follows another in the field of weather. Not sure what that means for us. We have had extreme heat and extreme dryness but also extreme wetness in some areas. Winter could definitely be interesting. Just have to start looking at how high the bees nests are, hard black are the wooly worms, how heavy are the corn shucks, etc… There are endless ways to predict the weather, the best being after it happens.
Kevin is there a website to get MTD avg hi/lo. I want to get it for D.C. and Blacksburg. Thanks
Those HPC rainfall prediction maps are fun to play with. Note: the area is too small to show on those maps, but in each of them there is a tiny white area (= no rain) about 8 or 9 miles SW of downtown Roanoke. My subdivision.
Not that I am pessimistic or anything ……
Played at Draper again. Creeks looked a little bit better today than on the 4th. Fairly heavy fog, but not where I feared it (at bridge over New River and at mile markers 102 and 101, just west of Claytor Lake). Just NE of the I-81 bridge over the Roanoke River (near the Ironto exit) and from the western C-burg exit (Exit 114) to just past the rest area at milepost 108. Clear sailing after that on the way there.
Matt:
Below is monthly/daily weather stats dating back to 1999 for all of the major sites in Blacksburg’s area (Blacksburg, Roanoke, Bluefiled, Lynchburg, Danville)
http://www.erh.noaa.gov/rnk/climate/f6/html/F6.html
You can all up Washington DC stats on this side by clicking on “Prelimary Monthly Climate Data (CF6)” at left and month you want on right:
http://www.nws.noaa.gov/climate/index.php?wfo=lwx
Michael Hoback – don’t forget counting the number of foggy mornings in August
Although I would love it, I don’t expect this winter to be another mild one, at least not significantly mild. The “experts” are all pretty sure that there will be an El Nino that is likely to reach minus 1.0 degrees in the 3.4 measurement area for at least three months, so unless the NAO (and/or AO) goes negative for an extended period, it is also unlikely to be a significantly cold winter, either. I foresee two basic scenarios: an overall average winter, probably with a few cold spells and also some periods of extended (14 days +) thaw. Or the storms happen at the same time that the cold spells are in place and we get 30 inches of snow (in ROA) … well above average. The latter is based on the fact that when there was an active winter in both the 80s and 90s, we got two others within a few years. If this winter falls below average again for snowfall, I will wonder if 2009-10 was an extreme anomaly in the overall snow drought that started in 1997.
Hey, Rick, comment 22. Thanks very much. How did you know that?
I have been watching Dave T.’s website for an update, but no update since July 5. Maybe he’s hiding since he kinda predicted that the midwest would turn rainy in July.
I’ll be very intested in the CPC’s August outlook for both temps and precip…………that comes out at 10am on Thursday.
I know from Twitter that Dave Tolleris has been on vacation. He came back today touting little change in U.S. weather pattern.
Doppler Carol, I will get my dried beans and my canning jar. One bean goes in the jar for each fog in August. Of course, we live in a valley and almost every morning in August is usually foggy and we never have that many snows unless you count the upslopes and flurries and then we probably do.