Monday Evening September 10, 2018 7:00pm
Chief Meteorologist Chris White
Good Monday afternoon. I hope your day is going well. We are all anticipating Hurricane Florence late this week and I will get right to the latest.
Hurricane Florence continues to strengthen in the open Atlantic and is picking up forward speed to the NNW at 13mph. Hurricane Hunters are out in the storm at this time and are sampling the structure and intensity. Mesovortices are seen on Goes-16 rotating around the eye. It is pretty remarkable to watch and have new images from the Goes-16 satellite ever 30 seconds. View it HERE but you will have to switch to infrared after the sunsets.
Some changes in the upper atmosphere today has allowed more of a NNW movement and the scary thing is that now Florence is likely going to get very close to category 5 status in the next 36 hours. Now the winds will likely come down as this storm gets close to landfall because of the shear it will encounter again. Also a ridge building over the Ohio Valley will slow Florence’s forward progress down Wednesday. Florence may slow and the central winds of Florence may come down into the category 4 range but Florence will grow in size. This increases the storm surge along the coast and broadens the impacts inland with high winds and rain. Therefore the only changes in our impact maps below will be to expand the extreme rainfall into central and eastern Virginia. We are keeping the moderate wind and rain threat in our entire viewing area and are holding onto the high rainfall impact along the Eastern slopes of the Blue Ridge. Even though current forecasts only produce 2-4 inches along the eastern slopes I worry that is underplayed a bit. So no change there. We will reevaluate these tonight during our nighttime briefing update.
Timing is next. Florence as said will slow in forward speed and some questions now rise as to just how strong that ridge is going to get to the North and East of Florence. Model data has definetely shifted to the NE of us today but the impacts will be felt well out from the center of Florence once inland because the wind field spreads out as it winds down. The next question is just how far southeast that front gets Wednesday. Models indicate that it will be over our area and work as a barricade to keep Florence from coming west. However, my experience tells me that these cold front are notorious for slowing down or stalling over or just west of the mountains. Some of the hurricane models are picking up on this too and are allowing Florence to move more West than North once landfall occurs Thursday Night.
For our area winds will start to arrive Thursday Afternoon and even with an eastward track of the center of Florence winds should still gust 40-60mph. Any shift to the West will increase those winds. Winds of 40mph can start to bring down trees and powerlines so we are forecasting a moderate impact from the wind event. The heaviest rain should arrive overnight Thursday into Friday and then it just depends on where Florence stalls as to how long this hangs out and rain holds on in the foothills.
We still reccomend preparing for poweroutages and widely scattered flooding.
Timing: Thursday Night through atleast Saturday Morning