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Weather Questions tagged “rain”

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Question: I live in Apex and would like to know why the majority of rain storms pass either to the north or to the south of Apex. In the last week alone I have had 0 drops of rain fall in my yard. But I can look out my windows and see lighting and dark grey storm clouds both to the north and south of me. This happens all the time. Unless there is a major storm the rain just seems to go around us. — Dave Nordaby

Answer: We suspect you're having a common perception that most of us do through the warmer half of the year, when convective showers and storms tend to occur in cells, clusters and small line segments that on a lot of days may only affect 10 or 20% of the area, so that by definition many more people see storms in the distance, hear thunder, or see them peppered about on radar displays (which tend to exaggerate a little how much surface area is actually receiving rain) than actually get rained on. This leads to the feeling that storms are almost always missing to the east, north, etc. However, we receive questions or comments to that effect from pretty much every corner of our viewing area, and when we check combined gauge and radar-based precipitation totals over the course of several weeks or months (along with long-term averages of those readings), we do not see notable small scale variations in the "normal" amounts, indicating that over time the coverage evens out. Through the course of late spring to early fall, almost all of us in the region can say that the majority of showers and storms pass us by, while a minority do cross over our locations and provide the sporadic rains (often including an occasional heavy downpour) that make up our overall precipitation during that span of time.
Jul. 26, 2017 | Tags: folklore, rain, thunderstorms, weather radar

Question: Hi! Is there a calendar online that shows when we last had rain; specific daily rainfall amounts for the area (instead of aggregate monthly or yearly data for the area (or less helpfully - the State))? Getting the right amount of water to my summer garden is tricky and being able to look back and determine how much water it needs would be helpful - relying on my memory alone is a faulty system. — Anonymous

Answer: There are a number of resources we can suggest, keeping in mind that rainfall can vary a good bit over a short distance. In terms of looking at specific dates and how much was received in rain gauges at individual stations, you can use the "Almanac" function of our web site to check a selected date - when you do that, the default is to show a single day's info for RDU. However, you can then change the view to "monthly," which will allow you to quickly scan a table of observations near the bottom of the page that includes daily precipitation observations for the entire month - you can also use the "Search for Another Location" box to change the observation site to another town. Another place to look for a fairly dense network of daily precipitation observations is the Community Collaborative Rain, Hail & Snow network, at www.cocorahs.org. Once you learn your way around the site a bit, you can get good localized history of recent precipitation for the region there. Another option is a National Weather Service Precipitation Analysis page that uses radar estimates of precipitation, adjusted to fit with rain gauge reports, to plot daily contours of precipitation that you can step through. The advantage here is that radar fills in some of the gaps between fixed observation sites. The page also allows you to view precipitation amounts summed over the past week, past month, past 90 days, etc, and to view how those amounts compare to normal. The address is water.weather.gov/precip/, and you might like to go to the "location" button, select "WFO," choose "Raleigh" and click on the county borders for a good view of our area.
Jul. 17, 2017 | Tags: cool sites, past weather, rain

Question: Elizabeth displayed a green chart this morning showing rain days and how much each day of June. Will this be posted on line? I would like to see this calendar page posted each month. It would help when planning when to plant and water. — Reginald tharrington

Answer: We're glad you liked that graphic, which shows the current month and how much precipitation was recorded at RDU on each day. Right now, we show that on a sporadic basis on the air, and post it on occasion in the "Weather Feed" space on our web site and app. We can look into posting it on a more regularly scheduled basis. We would also note that there are a couple of resources you can find on our site already that convey the same information in different forms. One is the set of cumulative rainfall graphs for RDU that cover the past 30 days, 90 days, year to date and past year. These graphs also include a line showing what would be the "normal" rainfall over those periods. In addition, you can go to our "Almanac" page, and click the "send" button under the "Enter Date" box - if you leave the date blank, it will default to the current day - this will take you to a history page for RDU. If you click the "Monthly" tab at that page and scroll to the bottom, you'll find a table that includes a column with daily precipitation values for each day of the selected month.
Jul. 8, 2017 | Tags: cool sites, past weather, rain, wral.com

Question: Is there a place where I can find running 24 hour rainfall totals? — Glenn

Answer: There are a couple of locations where you can get running 24-hour precipitation estimates based mainly on radar returns. One map of that sort is hosted at the Southeast River Forecast Center, at www.weather.gov/images/serfc/24_hour_precip.png, and a similar, but zoom-able, and more interactive, map at www.iweathernet.com/total-rainfall-map-24-hours-to-72-hours (you can click on any point there, and after a short delay, a box will appear that shows the estimated precipitation amount for that location).
Jul. 1, 2017 | Tags: cool sites, rain, weather radar

Question: My husband and I take our morning walks along the "Mountain to the Sea" trail along the Neuse River. The last few days the river appears to be very low. Any idea as to why? — Janie McAdams

Answer: The Corps of Engineers regulates flow from the Falls Lake dam into the Neuse River downstream based on the amount of inflow to the lake from upstream, the elevation of the lake surface and the need for flow downstream from the lake. Starting around a week into June, flows into the lake became rather low and by around the 10th or 11th of the month, the lake level had fallen and outflow from the lake downstream was minimized, which likely led to the low river level you noticed not far downstream from the lake before sending in your question on June 16th. Conversely, very heavy rain upstream of the lake on the 19th into the 20th has sent inflows and the lake level sharply upward, and we suspect you may have seen, or will shortly, noticeably higher river levels due to increased releases from the lake. You can check on a variety of level, inflow, outflow and water temperature data for Falls Lake at epec.saw.usace.army.mil/fall.htm, and more generally for lakes in our region at epec.saw.usace.army.mil/index.asp.
Jun. 24, 2017 | Tags: cool sites, lakes and rivers, rain

Question: Recently something is not working for me with the Doppler that was working before and I wondered if there was an explanation. For example, this morning at 10 am the Doppler showed Raleigh and most of NC clear with just a few scattered rain area SW from SC. I use 30 mph for approximate movement, which should have put any rain here pretty late in the day or night. Now it is 1 pm and heavy rain is falling with a large area of storming over central NC. I have used the Doppler successfully for a long time to plan my day (painting, clothes drying, hiking, etc) but now it does not seem to be working. It is causing problems. Do you have any explanation? — Margaret Parrish

Answer: We're actually a little surprised that planning based on a view of Doppler radar returns at any given time has worked all that well for planning out long periods of the day, since the radar can only show precipitation that currently exists, or, in time lapses, how it has evolved over a period of time. While one can reasonably extrapolate for a short time into the future based on the recent movement of rain areas or storm cells/bands, etc, it is quite common for rain areas and convective cells (showers and thunderstorms) to rather rapidly increase or decrease in size and intensity, to speed up or slow down in terms of forward motion, for existing rain areas to dissipate, or for new showers or storms to develop where none previously existed. We attempt to account for this as best we can in forecasts based on projecting current patterns, accounting for the typical behavior of the atmosphere when certain features (fronts, lows, upper troughs, etc) are in the vicinity, and using computer models that produce projected estimates of the future location and intensity of precipitation areas. We'd suggest combining your use of the Doppler display with checking the probability of precipitation in hourly forecasts, reading the text discussion of the forecast in our 7-day forecast, using extra tools such as the "FutureCast Radar" layer in our iControl display, and checking in on TV in the morning, when we often show forecast models that give a rough sense of the timing and location of any precipitation areas throughout the day ahead.
Jun. 9, 2017 | Tags: general meteorology, rain, weather radar, wral.com

Question: Why don't you show the monthy and ytd rainfall totals vs historical avg. At least put it on your website and update it. — James Spoo

Answer: We actually do that already, and then some. Just look in the "Weather Resources" section of our site, go to the second page and you'll see a link for "RDU Rainfall Totals -- Normal vs. Actual." It shows graphs and boxes with observed versus normal rainfall at RDU over periods that include, 30 days, 90 days, year-to-date, one year and five years. The direct address is www.wral.com/weather/page/1934052/.
Jun. 7, 2017 | Tags: normals, rain, wral.com

Question: How can you measure the speed of rainfall by looking at radar from one town to another? Does any of WRAL's apps provide means to measure the speed rain is traveling? — Bobby

Answer: The radar sections of our apps do not have a readout or built-in means of showing what the speed of rain areas is, but you can get a sense of that by using the lapse functions either on the Dual Doppler 5000 displays, where you would choose the view you’re interested in and then select the “1-hour” lapse, or by viewing the iControl radar display and clicking the “play” arrow, which will show about a 50-minute long lapse. You can figure a rough speed by following a rain area or storm cell across an area of known distance and dividing that distance by the elapsed time. For example, on the 1-hour lapse, if a band of rain moves halfway from Raleigh to Rocky Mt, that’s about 25 miles, so the band is moving around 25 mph.

Also, in situations where there are severe thunderstorm or tornado warnings in place, you can read the text of the warning and it will usually include a statement that gives the direction and speed of movement of the storm responsible for the warning.

May. 21, 2017 | Tags: rain, thunderstorms, weather radar

Question: Why did you remove the current rainfall amounts from the "Current Conditions" page? — Stefan M

Answer: When the web site was being changed a bit to accommodate changes in the graphics system that we use on-air, we decided it made sense to have the rainfall data consolidated with other kinds of maps in the "Map Center" section of the site. You can find the most recent daily precipitation values (the amount since midnight) for many stations around the viewing area by going to the Map Center page and clicking "other maps" where you'll see "rainfall" as one of the selections. There is a Map Center link in the "Maps & More" box just below the 7-day section of our main weather page.
May. 17, 2017 | Tags: maps & codes, rain, wral.com

Question: In the Sanford area what was the amount of rainfall on Monday night, May 1st? Also, what was the speed of wind gusts for the same day and area? — Joe Russell

Answer: For rainfall in that period, we checked observations from the Sanford-Lee County airport and also radar rain estimates for the surrounding area. The airport recorded .19 inches of rain, with radar indicating a general range of about 1-3 tenths of an inch across the county. Winds were gusty in the afternoon and evening, with the top gust at the Sanford airport reaching 30 mph, but some nearby locations recorded gusts as high as 35-40 mph. In addition, there were quite a few reports of thunderstorm gusts strong enough to bring down trees just to the west, although that band of storms tended to weaken by the time it moved east of about Randolph County. To see a Storm Prediction Center map of reported high wind damage from the afternoon and evening leading into that Monday night, see www.spc.noaa.gov/climo/reports/170501_rpts.html.
May. 14, 2017 | Tags: cool sites, past weather, rain, severe weather, winds

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