Hampton Roads: Winter Weather Possible Early Next Week

The snow today across Hampton Roads may just be an indication of what we’ll see next week if the storm system I’m tracking verifies.

The setup for a potential storm next week all starts coming together today- an arctic cold front pushed across the region Thu afternoon, bringing colder air and windy conditions. Another cold front will push through the region Sat night bringing another chance for some light snow to Hampton Roads. Afternoon highs on Sunday will struggle to reach 30°F in some spots while wind chill values (feel-like temps) are in the single digits at times, allowing very cold air to make the ground cold and ready for any type of winter precip. When winter precip falls onto the ground that has been in the 30s, it has no problem sticking to roads and grass.

As we go into Tuesday, a  low pressure system looks to form off our shore. The question is- when and where does this low form? If the low tracks NW of Hampton Roads, we would get in the zone of all rain and no snow. However, if it tracks east of our region and off the coast, we could have a setup that provides snow to the region. The type of precip is also up for debate at this time. If high pressure builds in to our north, we could have a situation where warmer air is aloft and causes sleet or freezing rain to fall resulting in more ice than snow.

As we go through the weekend, we’ll have to keep an eye on how the models handle the system and see if a trend develops. Forecasting towards the trend is often one of the best ways to determine where a system may go.

GFS Model depiction of types of precip that could fall:

gfs_ptype_accum_nc_25gfs_snow_depth_nc_25Tue night snow Hampton Roads gfs_ptype_slp_nc_24

Meteogram showing model precip amounts through Tuesday. Note how there is still uncertainty,indicated by one model run being lower than the other and another model showing a Wed snow event while an earlier run only showing a Tuesday event. Models

Tuesday Afternoon Update- Tropical Storm Arthur

Well since my last blog post the disturbance off the southeast coast has strengthened and is now classified as Tropical Storm Arthur! This is our first named storm of the 2014 Atlantic Hurricane Season. Arthur still seems to be on track to impact Eastern VA and especially Eastern NC as we approach July 4th with some rain, wind and coastal flooding.

To strengthen, hurricanes need several things. First, they need little wind shear to allow t-storms to form over the center. They also need warm sea surface temperatures and moist air. To get a very strong storm, typically you’d want to see some good symmetry on the system too with storms around each side of the center or eye of the storm.

symmetryAt 2 pm Tuesday, the storm was off the coast of FL and becoming better organized. In the past few hours, we’ve noted a flare up of t-storms on the northern side of the system, which is what you want to see if you want the storm to strengthen. In the image to the right, I’ve outlined each quadrant and talked a little about the storm activity in it. For the past day, most of the storms associated with Arthur have been on the southern side so this flare up on the northern side is noteworthy.

Water Vapor TueIn terms of moisture, there is some dry air on the northern side of the system in the mid levels which I believe isn’t really allowing storms to fire up significantly on the northern side of the system. As we go through tonight and tomorrow though, we expect the storm to overcome this dry air and get better organized. So, with 2 out of 3 of the ingredients seeming to becomd more favorable, what about sea surface temperatures?

usatlant.cfWell… sea surface temperatures also seem to support a tropical system. Usually you want temperatures in the upper 70s to 80s to support tropical storm or hurricane strength storms. With the warm Gulf Stream waters near the storm, these temperatures won’t be an issue and we expect the storm to strengthen as atmospheric conditions become more favorable with the combination of these 3 features improving.

The National Hurricane Center’s current track expects Arthur to approach the Outer Banks as we go into Thursday night and Friday morning as a Category 1 hurricane. Note though that Hampton Roads and Eastern Carolina are still in the cone of uncertainty. A 25 mile jog to the west could significantly change the impacts to the Outer Banks and VA.

So what is the bottom line? Basically, we just need to watch it. Right now, the storm system does not seem overly significant for Hampton Roads and if storms do not fire on the western side and we don’t get good symmetry of the storm, rain and wind will be pretty tame across Eastern VA. Hatteras,NC seems to be in the path to take the brunt of the storm. If you’re traveling down there, be aware of conditions and know that water often covers NC-12 in spots during storms. Be prepared to even be stuck there if the road gets washed away or sand covered. NCDOT will do their best, but you can’t always beat Mother Nature.

Main Headlines:

– Rain and some wind possible Thursday night into Friday morning across Hampton Roads
– Biggest impacts with Tropical Storm strength winds across NC Outer Banks
– Dangerous surf conditions with rip currents and large waves
– Conditions improving Friday night across all areas
– Weekend perfect across the area! Don’t cancel plans.

What you should do:
– Stay Tuned…
– If traveling SE to the Outer Banks Thursday night or Friday, consider postponing until Friday afternoon

Tropical Trouble on the 4th of July?

A tropical disturbance off the coast of FL could cause trouble to vacationers heading to the Outer Banks or southeast coastline as we approach the 4th of July holiday. The main impacts to Hampton Roads, depending on the track would be some heavy rainfall Thu night into Friday, minor coastal flooding, rip currents, increased waves and some gusty winds.

TropicalAs of 5pm Monday, an area of storms located off the eastern coast of FL was starting to get better organized and could become our first tropical system of the year. If this happens, it would be named Tropical Depression 01 and then Arthur once it has sustained winds of 39mph. USAF Reserve Hurricane Hunter Recon aircraft found 30-35 mph winds Monday afternoon, but insufficient t-storms around the center caused the National Hurricane Center to not name the system yet. It wouldn’t shock me to see this area classified as a tropical depression Monday night or Tuesday.

Those of you who have lived on the coast for any amount of time know that the track of a system is key to the impacts. At this time, most of the model guidance is showing the system moving NW then turning NE and skirting the NC coastline as a front approaches from the west and helps to curve the storm away from the coast.ecmwf_slp_precip_nc_15 In the picture to the left, you can see the front and the storm approaching on the European Weather Model. The key to our impacts, is when does the front arrive and how strong is the storm when it does? Typically, a stronger storm would be impacted more by the front. A weaker storm though, could bring more rain to us as the front interacts with the system and causes the rain to spread north.

Intensity forecasting is tricky, and with a storm close to the coast there isn’t much room for error. Personally, this does not look like a huge system but keep in mind, even a strong tropical storm or a weak hurricane can cause many issues, especially on the vulnerable Outer Banks. We’ll have lots of people in Eastern NC and SE VA this weekend who may have never experienced a hurricane or even know what one is. If you’re reading this and that applies to you, don’t cancel your plans though! The weekend Saturday and Sunday looks excellent once the storm passes.

So Here is the Bottom Line:
– Area of storms off the coast of FL could become our first tropical storm this season
– Most likely track for now shows the storm brushing the Outer Banks of NC
– Rain, gusty wind, high waves, dangerous ocean conditions and coastal flooding main impacts across NC,SC and VA.
– Those traveling to the OBX for 4th of July Weekend should NOT cancel plans, but be aware. After Friday, Sat and Sun look excellent!

What You Should Do:
– Keep aware of future forecasts
– Be prepared for some heavy rain, tropical storm force winds (39+ mph) and some coastal flooding late Thu into Friday.
– Know that 4th of July Fireworks may be canceled in many areas depending on the track.