The official start of hurricane season isn't until June 1 for the Atlantic basin, but we already have an eye on the tropical Atlantic for the possibility of "subtropical" system developing over the next few days. A subtropical system is one that exhibits both tropical characteristics and those of a “winter-style” storm. They're not all that uncommon, especially on the edges of hurricane season (May and December).
A disorganized cluster of showers and thunderstorms was located just east of Florida and near the Bahamas Tuesday morning. This area of showers and storms is expected to become a little better organized through the mid-week period, eventually becoming a low pressure system off the southeast coast.
If the current model guidance holds true, the low will track over the warm waters of the Gulf stream. Water temperatures just off the Carolina beaches are currently in the upper 60s to lower 70s. However, just offshore, water temperatures are nearly 80° over the Gulf stream.
These waters are warm enough for this low pressure system to gain some tropical characteristics. That's why we may eventually refer to this as a "hybrid" or "subtropical" system. If the low pressure eventually becomes a subtropical storm it would take on the name Ana, the first storm of the 2015 season.
In the end, it's really not all that important whether this system becomes a subtropical storm or remains a non-tropical low, the weather impacts will likely remain the same for the Carolinas, but those exact impacts remain a bit uncertain because of model discrepancies.
We're not expecting this to become a very strong system, but the exact track remains a bit muddied and that's what makes this a complicated forecast. The majority of computer model data Tuesday morning suggested the low will meander off the Carolina coast through the end of the week and the Mother's Day weekend. This would keep the heaviest rain off shore, but would definitely be an issue for anyone traveling to the coast this weekend, making for windy conditions along the coast along with dangerous rip currents for those wanting to hit the surf.
A track closer to the coast would bring more rain to the region, while a track farther offshore would bring less rain.
As for the WBTV viewing area, based on the model data we're seeing Tuesday morning, it seems the chance of heavy rain getting this far inland is a long shot – at best. We'll continue to monitor the data and update the forecast as necessary.
In the short term, high pressure has built in and will stay with us through the mid-week period. First of all, the high will keep most of us on the dry side, as there's only a 10-20% chance of a shower through Wednesday. The exception is the higher elevations and foothills, where a little better chance for an afternoon shower or thunderstorm exists.
The second thing the high will do is keep us warm. By pulling winds out of the south, highs will remain above average, keeping us in the low 80s through the week.
The next best chance of rain will be on Thursday as a weak front moves through. Beyond that, it looks as if we will stay quite warm going in tot eh weekend and unless things change – rather dramatically – the chance for any real appreciable rain looks to remain low.