Tropical Storm Hanna Approaches
Friday, September 5, 2008; 2:00 PM
The metropolitan Washington weather forecast today is partly to mostly sunny skies in the morning with the afternoon bringing increasing clouds with a 40 percent chance of evening showers.
"The main event comes overnight and tomorrow with heavy rains -- 2-4" inches in some areas with locally heavier amounts -- that could cause flooding in spots, and winds that could reach sustained speeds of 30 mph and occasional gusts to around or above 50 mph. Overcast skies will limit highs tomorrow to the 70s," reports the Capital Weather Gang on their blog.
Meteorologist Steve Tracton of the Capital Weather Gang was online Friday, Sept. 5, at 2 p.m. ET to discuss the latest information on the approaching storm.
A transcript follows.
New Baltimore, Va.: Is it unusual for rain to precede a tropical storm by 375 miles? It's already raining in the Outer Banks, and the storm is still 375 miles southwest of Wilmington.
Steve Tracton: There are some relatively narrow bands of rain to the north, northeast of Hanna. I don't think they are the the oft mentioned feeder bands normally referred to. Rather, they seem to be the result of interaction with a broad warm frontal band - in geek terms, referred to as resulting from warm air advection. It's not unusual at all for the character of the precipitation and wind field to broaden and become more asymmetrical when a tropical storm begins to interact with frontal zones, etc at higher latitudes
Reston, Va.: Do you think NASCAR will be able to actually have the Richmond Sprint Cup race Saturday night? With the projected rain and wind, I think would cause them to postpone the race until Sunday, but NASCAR has not made a decision yet. When do you think we'll know the actual course of the storm through Virginia? Thanks!
Steve Tracton: I'm not sure what it takes to postpone a NASCAR race, but there's little doubt there will be very heavy rain SAT PM and evening - at best an extremely wet course. I don't think winds should be too much of the problem - it's the rain that will likely be the deciding factor.
Arlington, Va.: Steve,
I'm supposed to do a long bike ride tomorrow that starts in Thurmont, Md., and goes up to Antietam and Gettysburg before returning to Thurmont. Looking at various weather forecasts (including your fantastic interactive map), it looks like we'll be okay since we're starting early in the morning and should be finished around 1:00. I figure there will be some wind and rain, but we'll be done before the worst hits. Am I reading things right? (There are about 1700 other cyclists who are also planning to do this ride). Thanks!
Steve Tracton: I agree the worst effects likely will not be before early Sat PM. But, there could be intermittent heavy downpours before then. Hope you folks have some good rain gear.
Arlington, Va.: Hi -- I'm planning to travel to Philadelphia tomorrow morning, leaving around 7:00 a.m. Think I'll be ahead of the storm, or am I better off leaving tonight? Thanks!
Steve Tracton: Rain now well ahead of the actual storm could very well begin early evening tonight with a possible break before the main rain area of the storm reaches the Washington Philly corridor tomorrow PM.
Bethesda, Md.: What's your guess as to road conditions between Baltimore and Bethesda tomorrow (Saturday) at 9 a.m.? At 1.p.m.?
I'm having a huge family event tomorrow at 4 p.m. (not reschedulable), and want to figure out what to recommend to people regarding travel times.
Steve Tracton: All I can say is that it's likely to be raining heavily with fairly strong winds. If it were me, I'd plan on well below normal speed limits just about all day Sat. All driving should be done with extra care - better to take more time in travel than risk driving as if the roads were dry.
Alexandria, Va.: We have a couple of small dead trees in our yard we have been meaning to cut down, but haven't gotten to yet. Are the winds going to be strong enough that I should be concerned? Do we need to secure anything "loose" in our yard?
Steve Tracton: Small trees should not be a problem. If they have stood up to thunderstorms this summer, I expect they'll withstand Hanna
Rockville, Md.: The forecasts I see seem to show Hanna over or near D.C. Saturday evening (the 1100 hours NHC 5-day forecast for example), yet the weather guys on the radio are talking about rain during the day on Saturday. Is this because the size of the storm is so big that we will be impacted well before the storm is on top of us?
When would you expect significant rain to starting falling in and around D.C.?
Steve Tracton: Rain well ahead of what might be expected from Hanna alone could very well be in the DC area by midnight.
Alexandria, Va.: Hi Steve and HELP!
I'm scheduled to fly from Dulles to Johannesburg, S. Africa tomorrow evening (5:30).
Any early word on major airport delays/cancellations or other horrors?
Steve Tracton: Normally rain alone doesn't affect aircraft operations and commercial aircraft normally are not bothered by winds expected from Hanna. However, you never know with airlines, especially arrivals and departures at Dulles can be affected by problems elsewhere, e.g., if your flight originates from NYC.
Washington, D.C.: I admit it. I'm having trouble reading the map. What time do we expect the worst of it to hit the D.C. area tomorrow?
Steve Tracton: It's a pretty sure bet the worst should occur between early tomorrow afternoon through most of the night.
Arlington, Va.: Hi there! I'm throwing a dinner party tonight. We're planning to be outside, on a porch with a decent overhang. Party starts at 7:30. Do I need to make an in-door rain plan? Hoping the answer is no!!
Steve Tracton: What's a decent overhang?? I have one I think is decent, but while you won't get wet directly from overhead, wind blown droplets and spray at my home would certainly call for moving indoors .Sorry about that -- been there done that!!
Alexandria, Va.: Please help me. I actually need a loaf of bread for tomorrow. I don't think I can make it through the Kafka-esque nightmare that is a Washington supermarket the day before a storm.
Steve Tracton: Make sure you get plenty of toilet paper and milk with the bread.
Stafford, Va.: Steve, are we looking at 2-4" in North Central Stafford County as well? I have been hearing forecasts of 3-6" and more for the area. The less the better, especially in such a short time frame.
Steve Tracton: Predicting the amount of precipitation at any given location is one of the most difficult problems in meteorology. The way I'd put it is for rainfall to be about 1 - 2 inches with higher amounts possible.
Bethesda, Md.: I have to drive from Bethesda to Centerville, Va., tomorrow afternoon for a number of athletic events. As of today they are not canceled. Can you give me an idea of what changes in conditions would mean they will be? I can't understand why some things are being canceled while others are going on just fine. Do counties make their own rules? organizations?
Steve Tracton: Each activity and responsible party has to weigh the forecasts and decide what to do. It depends upon what they consider their "threshold of pain" - what are they willing to accept before makng the call.
Baltimore, Md.: Longer term forecast: There are other storms out there -- notably Ike. I am flying out of BWI early next Saturday and was wondering if the models show other storms tracking this over the coming week. Thanks.
Steve Tracton: It's impossible - and don't let anyone tell you differently -- to provide a reliable forecast for over a week from now!!!Having said that there is a non zero, but low probability IKE could be a factor. Stay tuned to CWG.
Arlington, Va.: The amounts of rain are all over the map -- what do you expect in DC? 2, 4, 6 inches?
Steve Tracton: As mentioned in a previous reply, forecasting the amounts of rain at any given location is extremely difficult and come with lots of uncertainty. It's clearly going to be a substantial rain event, but exactly how much, break out a rain gauge and see for yourself after the fact - this is not meant to be a copout, just a fact of life
Alexandria, Va.: My family has a week's time share in Kitty Hawk, North Carolina, beginning tomorrow. What time do you think it would be safe to hit the roads this weekend to head south and do you think anyplace along the N.C. coast would be flooded out by Hanna? Thanks
Steve Tracton: I can't say anything specifically on flooding, but if you don't leave soon, it'll be to late to avoid the worst.
Friday Plans: Jazz at the Sculpture Garden, tonight, outside, 5 - 8. Yes or no?
Steve Tracton: YES, but your time frame is not to far from at least a possible no.
Washington, D.C.: Is the general rule of thumb for travel tomorrow that earlier is better? I have a 9:40 a.m. flight out of BWI tomorrow morning and was wondering if it's worth trying to switch onto the 8:40 a.m. flight instead. Would an hour be likely to make a difference?
Steve Tracton: I doubt that little difference in departure times will make a difference - at best is a 50- 50 proposition
Alexandria, Va.: Hey Steve,
What can we expect from Hurricane Ike that is coming up behind Hanna? He seems to be on her heels when looking at a map but I imagine that can be deceiving. Could the two storms together start to add up for us? And when, if at all, may we expect Ike in this area.
Steve Tracton: Its much too early to say anything useful on IKE at this point. The best guess -- and that's all it really is or could be -- is a strike over southern Florida, but it equally as well could move south of Florida into the Gulf or curve northwards along the east coast. Again, stay tuned to CWG for the most up to date and reliable information!
Chesapeake Beach, Md.: I live on the Bay (my backyard) and am anticipating some pretty heavy waves and flooding. They're saying a surge of 2-4 feet and I was just wondering what was Isabel's surge (by way of comparison)? We're already preparing for a few days of no power and no well water.
Steve Tracton: Sorry, but I don't have information on the surge of Isabel readily at hand. The key with Hanna is whether the storm tracks east or west of the Bay - west being the worst situation - southerly winds pushing water into the Bay. Good move to prepare, since it could go either way.
Arlington, Va.: In predicting Hanna's path on the Capital Weather Gang's map, it looks like there are 10 or so forecast models. How do these models differ from one another (in terms of input, parameters, etc.) and how are their results used to get one "predicted track"?
Steve Tracton: I'll be doing an article on this subject which is expected to be on the CWG site on Monday. It will not get into the nitty gritty of the differences between models. Feel free to comment on this post and I'll provide more in a reply.
Thanks for your interest - it's an important subject!!
Pawleys Island, S.C.: We aren't expecting Hanna to be here until midnight or so and we have had very heavy downpours for the last hour. Winds started picking up around 9 a.m. this morning. The sea is beautiful but angry as it is churning. Though it's just supposed to be a tropical storm here, I would recommend putting your deck furniture near the house and taking any hanging plants down or anything else that is hanging around your house.
Steve Tracton: Good advice: Even if not officially a hurricane, the damage and danger can be as great as a CAT 1 storm. The rain you've been experiencing,m as I've mentioned earlier is associated with, but not the direct influence of Hanna alone.
Bethesda, Md.: Hi Steve. I'm a Bostonian and I was a kid when Bob came through, and even then, where I was, we just got a lot of rain and very little wind, so, I'm not used to tropical storms/hurricanes/etc. Living in a high-rise apt. in Bethesda, are there any preparations I need to be taking? I have plenty of water, canned goods, manual can opener, flashlights, etc. Do I need to worry about the side of my apartment that's all floor to ceiling windows, and if so, what do I do? Should I be staying away from the windows during the day tomorrow? (essentially confining me to the bathroom or the first floor lounge?)
Steve Tracton: I just love Bostonians - naturally, that's where I'm from. I doubt you'll experience anything more with Hanna than with Bob. Except for the minimal chance of tornado touching down in Bethesda, If you've made it through some of the severe thunderstorms this summer, I wouldn't sweat about windows blown out.
To all: I've tried to avoid giving advice on what to do - though in haste I may not have been totally successful. Following the great advice I've received from Bob Ryan, the best approach is to say what I (or he) would do - not what you should do. We provide the best information possible - you all decide what to do. That's likely to be different for every individual or circumstance.
Steve Tracton: It's about time to sign off - I greatly appreciate your interest. On behalf of the entire CWG thanks and good by.
But, I'll take some questions offline via email. Send to Stevet@mailinator.com. I can't promise, however, an immediate response.
washingtonpost.com: Tropical Cyclone Report/Hurricane Isabel ( National Hurricane Center)
Editor's Note: washingtonpost.com moderators retain editorial control over Discussions and choose the most relevant questions for guests and hosts; guests and hosts can decline to answer questions. washingtonpost.com is not responsible for any content posted by third parties.