Hurricane Hunters found a closed low Saturday morning. Potential Tropical Cyclone 18 is upgraded to Tropical Depression 18 with 35 mph at 11 AM. Squalls drench western Cuba and a wet late Saturday and early Sunday is in the cards for South Florida and the Northwest and Central Bahamas. As of 11 AM the National Hurricane Center anticipates strengthening to Tropical Storm Philippe by Saturday evening. This will pass close to extreme Southeast Florida overnight Saturday into Sunday with winds of 45 mph. A Tropical Storm Watch is in effect for the upper Florida Keys and Southeast Florida. Wind shear will keep future Philippe a weak tropical storm. It merges with a cold front and transitions to an extra-tropical system by early Monday over the western Atlantic. A stronger area of low pressure in conjunction with that same front drenches New England late Sunday and Monday. Winds could gust up to near hurricane force near the coast.
Future Philippe brings the threat of flooding to South Florida and the Keys through early Sunday. While widespread 2-4″ of rainfall is likely, isolated areas could pick up 6-7″ of rain. Below is the RPM rainfall accumulation forecast through Sunday.
Wind gusts near tropical storm force are possible in the Florida Keys and in South Florida Saturday evening and overnight Saturday into Sunday. Below is the GFS wind gust forecast at 10 PM Saturday. Wind gusts are stronger in a severe summertime thunderstorm.
Late Friday afternoon, the National Hurricane Center tagged Potential Tropical Cyclone 18 in the western Caribbean. Lacking a low-level center, it’s not yet qualified to be a tropical system, but it’s expected that this will become Tropical Storm Philippe later tonight or early Saturday. This system will accelerate to the northeast, moving quickly across Cuba on Saturday and the Bahamas on Sunday.
The biggest impact from the quick-moving Philippe will heavy rainfall potential across Cuba, the Bahamas, and South Florida:
Cayman Islands, Cuba and Bahamas: 4-8″ with maximum totals of 10″
South Florida and the Florida Keys: 3-5″ with maximum totals of 8″
A cold front will sweep through these areas quickly Sunday into Monday, bringing cooler temperatures, clearing skies, and windy conditions.
Invest 93L continues to show no signs of further organization Thursday morning. It remains nothing more than a disorganized area of showers and storms with a weak circulation. The disturbance has struggled immensely with land interaction over the last couple of days and that will continue over the next 24 hours. It will however have a narrow window Friday & Saturday over the northwestern Caribbean when some weak development is possible. Beyond that time, upper-level winds associated with our next cold front will create a much less favorable environment for development. A tropical depression, or even weak Tropical Storm Philippe, nearing the Keys or South Florida on this weekend is not out of the question, but it’s just not a scenario that models have been favoring as of late.
Regardless of development, this disturbance will be a big rain maker for parts of South Florida and the Keys. Widespread rainfall totals of 2-4″ are expected with isolated higher amounts possible. Amounts will taper off quickly further north in the state.
Florida, along with the rest of the Southeast, will clear out quickly behind the front and unseasonably cool weather will set in for Halloween. Meanwhile, 93L will contribute to the development of an intense nor’easter-style storm that will bring very heavy rainfall, localized flooding, and whipping winds to parts of New England Sunday into Monday.
Below: GFS 24 hr rainfall totals valid at 8am Monday morning… Image courtesy tropicaltidbits.com
The 2017 Atlantic Hurricane Season may not be over just yet. The last couple of days we’ve been watching an area of disturbed weather over the Western Caribbean and Central America. So far, land interaction has been the main limiting factor, but conditions should be a little more favorable over the next day or so as this disturbance (Invest 93L) moves slowly north into the Northwestern Caribbean.
While this an area that is notorious for late-season hurricanes, model trends have not been particularly concerning as of late. As 93L moves into the southern Gulf over the weekend, it will be merging with the next cold coming across the Southeast and into Florida. This front will introduce stronger upper-level winds, likely preventing 93L from developing any further. Nonetheless, it bears watching. Regardless of development, heavy rains are headed for South Florida this weekend.
The second to last month of the 2017 Atlantic season winds down. On Saturday there are no areas of interest and no tropical cyclone development is expected over the next 5 days. A tropical wave in the western Caribbean stirs up convection near Central America. Pressure will stay general slow in this area for the next several days.
Long-range computer models have been back and forth on possible development in the western Caribbean at the end of October or early November. The 0Z Euro shows no signs of an organized area of low pressure in the southwest Caribbean through Thursday October 26th. The 06Z GFS also shows no sign of tropical depression development.
We’ll keep an eye on this region over the next 5-10 days. Looking ahead to November, tropical cyclone development is less likely, but not unheard of. Five percent of named storms form in the last month of the Atlantic season. November Climatology shows any activity typically forms in the western Caribbean and drifts northeast.
Time ran out for Invest 92L east of the Bahamas. Wind shear is on the rise Tuesday as a cold front approaches. Upper level winds are not conducive for tropical development in the days ahead as this feature merges with a frontal boundary.
No tropical development is expected for the next 5-7 days. The ECMWF shows no areas of concern through next Sunday. The long-range GFS hints that the western Caribbean is worth watching next week. It’s a ways off, but this makes with climatology.
Former Hurricane Ophelia brought heavy rain, gusty winds, and coastal flooding to Ireland Monday. It is the strongest storm of its kind to hit Ireland since Debby in 1961. The core of the non tropical low moved ashore in southwest Ireland Monday morning EDT. According to the Irish Meteorological Society a gust of 97 mph was reported in Roches Point Co. Cork. Fastnet Rock, about 4 miles offshore of the coast, saw a gust of 109 mph. The remnants of Ophelia will brush the western United Kingdom late Monday EDT.
Closer to home Invest 92L shows some signs of life early Monday. The area of low pressure east of the Bahamas is broad in nature, but it is producing wind gusts near tropical storm force. Convection increases early Monday under moderate westerly shear. Upper level winds become even less conducive for development mid-week as Invest 92L lifts northward and merges with a frontal boundary. This energy may pass near Bermuda late Tuesday. If this feature gains tropical characteristics it will called Philippe.
Upper level winds become less favorable for organization of Invest 92L Tuesday and Wednesday. Notice all the red indicating high shear around the southeast U.S.. These hostile upper level winds shift east into the western Atlantic mid-week. The graphic below is courtesy NOAA/The University of Wisconsin at Madison.
Ophelia became the 10th consecutive hurricane of the hyperactive 2017 Atlantic hurricane season mid-week over the north Atlantic. It is rare for hurricanes to form this far east. On Saturday morning Ophelia is the furthest east Atlantic major hurricane in history. This is according Dr. Phil Klotzback of Colorado State University. Ophelia is the sixth major hurricane of the season. As 11 AM EST Saturday max sustained winds are at 115 mph. The core of the storm will pass south of the Azores Saturday evening and early Sunday, but squalls will reach the Southeast Azores. Ophelia will transition to a non tropical system over cooler waters as it approaches Ireland Monday. While it will be an extra tropical system during this time, it will still bring tropical impacts. Hurricane force wind gusts and heavy rainfall are likely Monday and early Tuesday EST.
We’re also watching a broad area of low pressure near the Leeward Islands. Upper level winds are hostile in the short-term. As of Saturday morning there is a 40% chance this becomes a tropical depression/Tropical Storm Philippe over the next 5 days. It may pass near Bermuda this work week, but is no threat to the U.S..
Tropical Storm Ophelia continues to get organized and will soon become our 10th hurricane of 2017 Atlantic hurricane season. Sea-surface temperatures in this part of the Atlantic Ocean aren’t incredibly warm, but upper-level winds are favorable for slow intensification.
Ophelia will head east-northeast over the next few days and eventually make more of a northward turn through the weekend. It is currently forecast to stay west of Portugal this weekend, before bringing gusty winds and rain to Ireland early next week.
It has been a season for the record books so far. Through today, October 11th, we’ve had 15 named storms – 9 of which have been hurricanes, and 5 of those 9 became major hurricanes (category 3 or higher). On average through this date, we only have 9 named storms, 5 hurricanes, and 2 major hurricanes.
To add to that, the 9 hurricanes we’ve had this season have been consecutive – Franklin to Nate. The last time we had 9 or more back to back hurricanes was 1893!
This season has been remarkable in so many ways and there’s still another 50 days to go before it’s over. Let’s hope it stays quiet until then.
Nate become the 4th hurricane of the hyperactive 2017 season to strike the U.S. (including Puerto Rico) this weekend. The last season with four or more U.S. landfalling hurricanes was 2005. It made two landfalls.The first near the mouth of the Mississippi River Saturday evening, the second near Biloxi Mississippi at 1:30 AM EDT Sunday as a category 1 hurricane with 85 mph.winds. The heaviest rain, strongest wind, and greatest storm surge was felt near and just east of the center.
Nate will be remembered for its coastal flooding, a threat often underestimated with tropical system. A storm surge of 6.3 feet was recorded in Pascagoula Mississippi. Social media was blasted with photos and video of flooding in the Golden Nugget Casino in Biloxi. Mobile Alabama was also hit hard with coastal flooding. A storm surge of 5.4 feet was recorded there. The graphic shows the rise in water in Pascagoula, Mississippi courtesy NOAA.
Nate weakens rapidly Sunday morning over land. As of 11 AM it is a tropical depression. Max sustained winds are at 35 mph as it races north-northeast at 24 mph. It will weaken to a tropical depression Sunday. Nate is big rainmaker for portions, of the Southeast, Tennessee Valley, and eventually the Northeast U.S through Monday.
Here is the 11 AM forecast track from the NHC. Nate will quickly lose tropical characteristics over the next 24-36 hours.
3-6 inches of rainfall, with isolated high amounts are expected from central Gulf coast up through the southern Appalachians. The Weather Prediction Centers estimates 7-8″+ are possible in spots. This train of moisture brings heavy rain the Tennessee Valley and the Northeast U.S. too. Here are rainfall estimates from the Weather Prediction Center through Tuesday morning.