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Posted at 9:00 PM ET, 09/ 5/2008

Showers Streaming In Ahead of Hanna

By Jason Samenow
Radar: Latest mid-Atlantic radar loop shows movement of precipitation over past two hours. Click here or on image to enlarge. Refresh page to update or restart animation. Powered by HAMweather.

*Tropical Storm Warning issued for immediate metro area and Eastern shore.*
*Wind Advisory for north and west suburbs between 8 a.m. and 11 a.m. Saturday*
*Flash Flood Watch for metro area Saturday morning through afternoon*

Live Chat Transcript

Hanna continues its relentless northward push towards our region. Rain showers have developed well ahead of the storm, and the first drops have already reached the metro area.

hanna-0905-2100.jpg
Hanna as of 9 p.m. Friday evening. Courtesy NOAA.

As of 8 p.m., Hanna was located about 200 miles south-southwest of Wilmington, N.C. with maximum winds of 70 mph. Thunderstorms have exploded around the center of Hanna. The cloud top heights in some of Hanna's thunderstorms now reach an astonishing 59,000 feet -- an indicator of intense convection. The bright red colors at the center of Hanna in the image to the right illustrate this convection. Hanna may briefly peak at minimal hurricane intensity before making landfall near Myrtle Beach, South Carolina late tonight.

Intermittent rain showers should continue overnight, with the rain increasing in coverage and intensity towards morning. A general 2-4" rainfall is likely over the immediate metro area, with the heaviest amounts along the I-95 corridor and just to the east. Winds will also pick up towards morning, with the strongest winds occurring from mid-morning to early afternoon.

RAINFALL MAP AND TIMELINE [UPDATED 9 P.M.]

9 PM FRI to 12 AM SAT
Occasional showers likely. Winds sustained from the south and southeast at 10-20 mph.
12 AM SAT to 8 AM SAT
Frequent showers with a few thunderstorms. A couple periods of steady rain. Winds sustained from the northeast at 15-25 mph.
8 AM SAT to 6 PM SAT
Heavy rain bands move through with thunderstorms mixed in. Winds sustained at 20-35 mph. Gusts to 50 mph.
6 PM SAT to 9 PM SAT Steady rain tapers quickly from southwest to northeast. Scattered showers and thunderstorms linger. Winds sustained at 20-30 mph. Gusts to 40 mph.
After 9 PM
Clearing skies and decreasing winds.

USEFUL LINKS

How to Prepare for Flooding, Blackouts and High Winds | Track Hanna | Satellite image | Southeast radar | Northeast radar

STORM FAQ [UPDATED 9 P.M.]


Estimated sustained winds and gusts Saturday.

How strong will the winds be? Could there be wind damage and power outages?

Occasional strong gusts of over 50 mph could be capable of bringing down some trees and power lines especially east of I-95. Some power outages are possible in the metro area. The most outages are likely to be near the Bay and to the east.

What precautions should I take?

No need to board up windows. But do ensure outdoor furniture and plants are secured and/or brought inside before you go to bed tonight. Does your sump pump work if your basement leaks? Have a flashlight handy in case the power goes out, and food and supplies that could last you and your family through a day or two without power, which is probably the worst-case scenario we would see with this storm. Here are a couple additional useful tips:

*Turning your fridge and freezer temperatures lower ahead of time and placing a 2-liter bottle of water in the freezer can help keep food colder longer if the power goes out.
*Remember to charge your cell phones and laptops tonight.

Keep reading for answers to more FAQs about the storm, including the forecast into early next week.

How confident are you in your forecast?

Confidence is toward the high side because most computer models are in agreement on Hanna's track. It's doubtful the storm will miss us. There's a small chance it could veer further east than expected and thus leave us with less rain and slightly weaker winds. There is also the chance that Hanna tracks somewhat further west than forecast, shifting the areas of heaviest rain and strongest winds west.

What is the flooding threat?

Widespread, major flooding is not anticipated. But basements, roadways and other low-lying areas that are typically prone to flooding will be at risk, as Hanna could dump several inches of rain in a very short period of time. Stay up-to-date with river levels and flood alerts for area rivers here.

Could there be a tidal surge along the Potomac?

The Weather Service is projecting two to four feet of storm surge along the western shore of the Chesapeake Bay and the tidal Potomac River on Saturday. The high tides to watch occur on Saturday morning and evening, but only minor coastal flooding is anticipated.

Could there be tornadoes?

An outbreak of tornadoes does not seem likely. However, it's not unusual for tropical systems to spawn at least a few tornadoes. Stay tuned to Capital Weather Gang during the storm. We'll let you know if any tornado warnings are issued by the National Weather Service.

When and where will the conditions be the worst?

Along and east of I-95, from sunrise through mid-afternoon Saturday.

Will flights be affected?

Most likely yes. Expect delays and even some cancellations due to the impact of the storm up and down the East Coast. Check your flight before heading to the airport.

Is it safe to drive?

Driving tomorrow will be comparable to driving in a gusty summer thunderstorm at times with driving rain and gusty winds. It can be done, but visibility will be reduced and it will take you longer to reach your destination. Reduced visibility, wet pavement and the possibility of debris on the roadway all increase the risk of accidents. These risks can be lowered by skillful and cautious driving.

How bad will this be at the Maryland/Delaware beaches?

Sustained winds of 40-60 mph and gusts to 70 mph could mean some flying debris, power outages and moderate beach erosion. Rainfall, on the other hand, should be less than here in the metro area. Probably no more than 1-2".

Will this be as bad as Isabel?

Not likely. Isabel produced sustained winds up to near 50 mph in parts of the area and gusts to near 80 mph. Hanna's winds will be weaker. Storm surges will also be lower with Hanna than they were with Isabel. There's a small chance Hanna intensifies a little before landfall which would bring winds closer to the levels of Isabel, but it's doubtful Hanna will close the gap.

When will the storm clear and what's the forecast for Sunday and beyond?

The rain should be over, or quickly coming to an end, and winds dissipating by Saturday evening, with clearing skies Saturday night and lows in the 60s. Sunday looks spectacular -- mostly sunny and breezy with highs in the upper 80s and decreasing humidity. Monday should also be nice, again mostly sunny with highs in the mid 80s and not too humid. Tuesday brings the next chance of showers and thunderstorms (about a 30-40% chance as of now) with a mix of sun and clouds and highs in the 80s.

By Jason Samenow  | September 5, 2008; 9:00 PM ET
Categories:  Tropical Weather  
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Next: Hanna to Blast Region with Rain and Wind

Comments

hope we get lots of wind and rain

Posted by: sam | September 5, 2008 9:17 PM | Report abuse

Guys,

What about western LoCo (Leesburg and west) ? Is it possible that Hanna will connect with the front currently in the Ohio Valley and produce heavy rain?

Thanks

BL

Posted by: brownlab | September 5, 2008 9:25 PM | Report abuse

Too bad Hanna didn't come on a week day, because school could have been canceled.

Posted by: Yellow Boy | September 5, 2008 9:26 PM | Report abuse

BL: There may be some enhanced rain from the front, but the latest guidance doesn't indicate a lot. You guys will be on the edge of Hanna's rain shield with a pretty sharp cutoff, so you could end up with a couple inches of rain, or not much at all.

Posted by: Jason, Capital Weather Gang | September 5, 2008 9:30 PM | Report abuse

In the infrared satellite image, there is the clear center of the storm with the highest clouds, and there are the clouds swirling around that center. Then, off to the northeast just a tiny bit, there is another center of high clouds (not as high) with clouds swirling around that. What is that? I'm not used to looking at infrared satellite, so I don't know if you usually see that cluster of clouds just barely to the NE of a tropical system or not.

I'm linking to the black and white satellite cause you can see the two swirls better. Not that you all aren't looking at this already...

http://www.rap.ucar.edu/weather/satellite/displaySat.php?region=CLT&itype=irbw&size=small&endDate=20080906&endTime=-1&duration=0

So what's going on there?

Posted by: Laura in NWDC | September 5, 2008 9:42 PM | Report abuse

I just realized this satellite image updates every 10 minutes, so hopefully what I'm talking about is still there when you click on it...

Posted by: Laura in NWDC | September 5, 2008 9:44 PM | Report abuse

No, maybe the actual image isn't updating, just the time stamp. I don't know. I'll stop posting now.

Posted by: Laura in NWDC | September 5, 2008 9:46 PM | Report abuse

Laura in NWDC, I see the little extra swirl too - almost as if two centers are circling each other, but I think that's something of an optical illusion. OTOH, I can't say what's causing that particular structure, either.

Posted by: ~sg | September 5, 2008 9:54 PM | Report abuse

A heavy downpour in Bethesda at the moment.

Posted by: Jed in Bethesda | September 5, 2008 10:18 PM | Report abuse

I've got a cross country meet in Hagerstown, MD. You think it will be canceled? PG County has already canceled activities. I really don't want to have to be at school tomorrow morning at 7. They say we run rain or shine as long as there isn't thunder or lightening...

Posted by: Peter - Bethesda | September 5, 2008 10:21 PM | Report abuse

Peter: One could only hope they would have the sense to cancel it.

Posted by: mcleaNed | September 5, 2008 10:25 PM | Report abuse

Any word on MoCo cancellations for sports/activities tomorrow ?

Posted by: MDScot | September 5, 2008 10:28 PM | Report abuse

Laura in NWDC:

Here is an animation of Hanna:
http://www.ssd.noaa.gov/goes/flt/t2/loop-avn.html

The cluster of convection to the NE of the core appears to be outflow from the storm, not another separate circulation.

Posted by: anonymous | September 5, 2008 10:28 PM | Report abuse

OK, downpour was very quick lived. :P

Posted by: Jed in Bethesda | September 5, 2008 10:35 PM | Report abuse

Peter -- If we had a "Not-a-Nice-Day-for-a-Cross-Country-Meet" stamp, tomorrow would definitely get one.

Posted by: Dan, Capital Weather Gang | September 5, 2008 10:37 PM | Report abuse

You could use a tiny hurricane icon for the No XCtry Meet stamp...

Posted by: ~sg | September 5, 2008 10:41 PM | Report abuse

Looks like Hanna is going a little more west at the moment. A few minutes of heavy rain a little bit ago.

Posted by: Sterling | September 5, 2008 11:01 PM | Report abuse

Had a period of heavy and steady rain but no lightning/thunder in Centreville VA. Rain has now stopped.

Spoke w MIL in Myrtle Beach about one mile inland. She reports light rain and breezy; "nothing to get excited about"

Please everyone be careful driving (if you must) tomorrow. Use your headlights & give yourself extra stopping distance.

Posted by: Centreville VA | September 5, 2008 11:07 PM | Report abuse

So does a 978 mb tropical storm set a record? or is TPC clearly ignore it's mission to protect lives?

Posted by: Tired of Subjectivity | September 5, 2008 11:19 PM | Report abuse

Tired of Subjectivity: be glad we're not talking about an 878 mb storm. As of now, both the government and the general public understand that inland evacuations probably aren't going to be necessary with Hanna considering the "Tropcial Storm" designation.

Posted by: mcleaNed | September 5, 2008 11:38 PM | Report abuse

mcleaNed, my point is that TPC is not doing their job. 978 mb is usually a strong cat 1 hurricane. I suspect that they are not changing the status b/c that is not what they forecasted, which is a shame. It also brings into question their skill scores. Once a re-analysis is done, it will later be classified as a hurricane.

Posted by: Tired of Subjectivity | September 5, 2008 11:43 PM | Report abuse

Tired of Subjectivity: According to its statements, the NHC has not raised the classification because recon aircraft have not recorded hurricane force sustained winds in the storm. NHC has consistently emphasized that there is little difference in terms of impacts between a 70 mph tropical storm and a 75 mph hurricane, and that Hanna may be a Cat 1 at landfall. In fact, at 11 pm they said it should reach the coast as a Category One hurricane.

But I don't think it would enhance public safety to declare the storm a hurricane until there is wind evidence to support that. But in general, you are correct that a pressure as low as Hanna's seems more typical of a minimal hurricane.

Posted by: Andrew Freedman, Capital Weather Gang | September 6, 2008 12:01 AM | Report abuse

Pleae allow me to kiss you’re a** for a second;

I really appreciate Cap Weather in times like this (and also, especially in winter weather events). You and the commenter’s really do an excelent job in explaining what is really going on. I hope that the WP realizes what a assert they have with your organization.

Now I will return to my general complaining about how you guys never get anything right (LOL)

BL

Posted by: Brownlab | September 6, 2008 12:03 AM | Report abuse

Brownlab: Thanks for the really nice comment. We work hard and are glad you appreciate it!

Going to sleep now, but will be posting updates all day Saturday, starting around 6 or 7 a.m.

Posted by: Jason, Capital Weather Gang | September 6, 2008 12:40 AM | Report abuse

Thanks for the hard work, Gang of Weather! How about the Cabin John Crab Feast from 2pm to 4pm. Will howling winds and a tidal bore be heading up the Potomac? Right now, all I hear is crickets and felt a light sprinkle when I went to the driveway to pick up my Post.

I hate hurricanes. Grew up on the Gulf Coast. The yucky, low pressure feeling as they approach, freight train winds that sent the Irish wife and mother-in-law with the kids to the interior hall and their rosaries. I vacationed in Prince Edward Island in 1990 with the whole family and was having great time taking the kids to see Anne of Green Gables, both the house and a beautiful musical that debuted in London to rave reviews, eating lobster, swimming in Carolina temperature water where the Gulf Stream comes into the south side of the island. Then I come out of our cabin one morning an G%#@*dammit, I say to myself, a hurricane is coming. In Canada! Sure enough, the island was evacuated as Hurricane Juan (I think) bore down. I remember driving home through Maine and whole trees were blowing across the interstate. One of the reasons I moved north was to get away from hurricanes.

Posted by: flynnie | September 6, 2008 5:20 AM | Report abuse

The comments to this entry are closed.

 
 
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