Posted: 5:47 am Thursday, September 7th, 2017
By Kirk Mellish
No major changes made from yesterdays forecast track as of now. It is worth noting however that a spread still exists in the longer range track prediction. There is certainly time for the storm to surprise in one way or another, either on intensity or on track so nothing is set in stone. Maybe the worst stays just off shore like Mathew last year? A near-miss dodging a bullet scenario, perhaps. Threat to Savannah/Charleston has grown.
As has been the case all along if you’ve been reading my blog posts since Monday, it’s a matter of when and where the storm makes the big turn north. That’s the key and thus Hurricane Irma remains a difficult and challenging forecast because of the anticipated north turn which IS going to occur sometime this weekend as moves into the Southern Bahamas and approaches southeastern Florida. The timing and speed of the turn is going to have HUGE implications as to what sort of conditions will hit Florida .. AND what sort of conditions will move into Georgia and SC/NC.
IF it goes into Cuba it can weaken a lot due to land/terrain interactions.
The storm is the size of Georgia, Alabama and South Carolina combined. But the strongest winds are near the eye about 40 miles in diameter.
IF Irma makes a trek up the East Coast from Miami to southern South Carolina as a Category 3 or 4 hurricane, as the models currently suggest, the portions of the coast that the eyewall touches will potentially see a massive and catastrophic storm surge, breaking all-time storm surge records and causing many billions of dollars in damage. Even areas up to a hundred miles to the north of where the center makes landfall could potentially see record storm surges. The area of most concern is the northern coast of Florida, the coast of Georgia, and the southern coast of South Carolina, due to the concave shape of the coast, which will act to funnel and concentrate the storm surge to ridiculous heights. If we look at storm surge maps we see that in a worst-case Category 3 hurricane hitting at high tide, the storm tide (the combined effect of the storm surge and the tide) ranges from 17 – 20’ above ground along the northern coast of Florida, and 18 – 23 feet above ground along the Georgia coast. If Irma is a Cat 4, these numbers increase to 22 – 28 feet for the coast of Georgia. This is a Katrina-level storm surge, the kind that causes incredible destruction and mass casualties among those foolish enough to refuse to evacuate.
MODELS SUGGEST NOT A CAT 5 at next landfall:
GLOBAL MODELS, ENSEMBLES AND STRIKE PROBABILITIES FROM THEM:
The long and short of it is, that UNTIL it makes the right turn North, U.S. landstrike will be highly uncertain:
BEST PERFORMING MODELS OVER THE PAST 5 DAYS:
The best of the best is actually the one showing it WAY east, but appears to be an outlier because doesn’t match current movement and location.
# Basic Global Models, one in green often does well with hurricanes, it too is an outlier:
There will be a sharp turn to the north at some point Friday night or Saturday. How sharp a turn to the north and WHEN it occurs will have a massive impact on the amount of damage to Florida specifically eastern and southeastern Florida will see, and will have a huge impact on what Georgia South Carolina and North Carolina will see on September 11 or 12.
The risk to the eastern Gulf of Mexico and the Florida panhandle and the western half of Florida is significantly reduced. Obviously because of the size and intensity of the hurricane IRMA these areas would see some wind and rain and possibly some damage but they would not see a direct hit.
In addition if this scenario holds eastern third of North Carolina as well as central and eastern Virginia and lower Maryland as well as the Delmarva would see some wind and rain. But outside of the tornado threat most of these areas would NOT see any wind gusts over 50mph.
Now it is POSSIBLE that Irma COULD turn sooner to the north… and pass further to the east of Miami and east coast of Florida ( and east of the 80- degrees west Longitude line. IF this were to happen …IF… it would alter Irma landfall in the Southeast states. In this possible scenario IRMA **COULD** make Landfall up by say Wilmington NC. If that were to happen… and it is a very real possibility… then central and eastern North Carolina …central and eastern Virginia …lower Maryland …the Chesapeake Bay and the Delmarva .. would see much worse conditions with much higher wind and rainfall. Over the coastal areas …the above mentioned portions could see winds gusting to hurricane force. So it is way too early to let your guard down in eastern North Carolina …central and eastern Virginia …central and eastern Maryland and the Delmarva.
****NOON Sept 7 MISC. NOTES UPDATE****
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