Hurricane Ophelia Undergoing Extratropical Transition as it races for Ireland and the UK

Update at 6:50 pm CDT Sunday:

Ophelia appears to have nearly completed the process to Post-Tropical based on satellite imagery, with the whole arrangement of frontal boundaries and more asymmetric wind field and lack of any significant tropical characteristics outside of some convection (thunderstorm activity) northeast of the center. Ophelia is still a hurricane-force cyclone (likely top sustained winds 75-85 mph) and impacts still expected to quickly increase over Ireland Monday morning with rain, damaging winds and dangerous surf and coastal flooding.

us_sat-en-087-0_2017_10_15_23_15_15810_126


 

us_sat-en-087-0_2017_10_15_19_00_15810_126

Hurricane Ophelia…at least it was still considered one at 11 am AST…is quickly transitioning to a hybrid post-tropical cyclone. I made up a schematic using current infrared satellite imagery. You can clearly see the transitioning hurricane becoming surrounded by cold, dry air on its’ back side, with its own warm, moist tropical air mass contributing to warm air advection ahead of it. And you can the developing frontal structure…cold front developing offshore Portugal and warm frontal cloud structure fanning out far to the north of the low center and offshore Ireland. The cyclone itself should be fully post-tropical in the next few hours, if it can’t be considered so already. Impacts (moderate to heavy rain and damaging winds) begin their arrival  Monday morning. My forecast for Ireland (written last night) can be found HERE.

Advertisements

Surreal view…a major hurricane near Western Europe.

Incredible views today…

Hurricane Ophelia set two records: 1) The highest latitude major hurricane on record in the North Atlantic Basin, set beginning at 35.9 N and 2) the most easterly major hurricane on record in the basin, set beginning at 26.6W. It will likely weaken below major hurricane force by Sunday morning as it begins to undergo transition into a frontal cyclone from its interaction with the jet stream and further reduction of sea surface temperatures below 72 degrees F/22 degrees C. However, it will be one for the record books.

Fortunately, Ireland and the United Kingdom will not need to worry about a major hurricane hitting them. They will need to worry about a likely damaging windstorm from a post-tropical hybrid cyclone. The post-tropical incarnation will develop frontal characteristics as it initially weakens, but its strong inner warm-core will continue to release some heat into the system, re-intensifying it as it becomes fully embedded in the mid-latitude westerlies and races into Ireland and the UK Monday afternoon and evening. My updated forecast for Ireland is below. Still expecting winds capable of downing trees and causing major power disruptions. The forecast for intense winds is high in confidence as computer models hone in on the center of the storm either coming ashore the southern tip of Ireland or just grazing the western shore. This is favorable for a “big blow” over the entire island. Residents need to be prepared to stay indoors and stay safe during the day Monday.

Ireland Forecast for Post-Tropical Cyclone Ophelia:

 

400px-Ireland_trad_counties_named
Forecast zones (North and South) used for my forecast.

 

Monday Morning (After 7 am local time): For the southern half of the island, wind gusts of 40-50 mph (64-80 km/h) will develop during the morning, increasing to 60-85 mph (97-137 km/h) by mid to late morning from the coast, northward. The strongest gusts will be along the coastal areas, especially the south shores where isolated gusts may approach 100 mph (161 km/h). For the northern half of the island, wind gusts to 40 mph will develop mid morning , increasing to 50-60 mph late morning, from south to north.

Monday Afternoon (After noon): For the south, wind gusts of 60-85 mph (97-137 km/h) early afternoon with isolated to 100 mph/161 km/h along the south/southeast shores). For the north, wind gusts of 50-60 mph (80-97 km/h) early afternoon will increase to 60-85 mph by mid afternoon with isolated gusts to 100 mph along the northeast shores, spreading from south to north into the late afternoon.

Monday Night (after 5 pm local time): For the south, wind gusts will gradually decrease to 40-55 mph (64-89 km/h) during the early evening from south to north. For the north, wind gusts will gradually decrease to 40-55 mph during the mid to late evening (after 7 pm) from south to north.

Sea conditions will be hazardous all around Ireland with wind gusts in excess of 100 mph (161 km/h) likely in the south coastal waters and in the Irish Sea.

us_model-en-087-0_modswisseu_2017101418_42_5594_149
High-resolution Swiss model showing the tightly-packed circulation of then Post-Tropical Cyclone Ophelia reaching coastal Ireland midday Monday. Damaging winds will be spreading throughout the Irish Republic and Northern Ireland by this time. Shown for illustration of the overall forecast scenario.

Hurricane Ophelia now a very rare Category 3 storm south of Azores

Hurricane Ophelia has strengthened into a Category 3 hurricane with maximum sustained winds of 115 mph as it moves south of the Azores. It is moving over prime atmospheric conditions, even as it overcomes waters of only 25 degrees C/77 degrees F. In normal tropical environments, tropical cyclones need water temperatures of 26 degrees C/79 degrees F to maintain themselves and warmer to significantly strengthen. However, the colder temperatures in the upper-atmosphere associated with the mid-latitude troposphere is providing Ophelia with ample atmospheric instability (warm, moist air rising into cold air aloft intensifying thunderstorm activity). In addition, mid-latitude dynamics are playing a role…the approaching frontal system and associated upper-level trough of low pressure approaching Ophelia is giving the system a “poleward outflow jet” to pull air away from the system and allow the surface low to strengthen.

us_sat-en-087-0_2017_10_14_16_15_15827_127
Meteorological Analysis of Category 3 Hurricane Ophelia. Favorable dynamic and thermodynamic set up allowing system to strengthen at high latitude, over cooler waters for hurricane maintenance. With that said, water temps under Ophelia are running 2-3 degrees C above normal, also allowing it to have its unusual intensity near Western Europe.

See my previous post from late last night for my wind forecast for Ireland. Strong winds should begin to impact the island midday Monday (local time), with stormy conditions lasting into Monday night. The southeastern Azores will see some gusty winds and 1-3 inches of rain as it passes by this evening and night.

–Meteorologist Nick Humphrey

Analysis and Forecast Impacts of Post-Tropical Ophelia in Ireland Monday

Hurricane Ophelia is a high-latitude hurricane by tropical standards…a Category 2 storm with maximum sustained winds of 100 mph as of 11 pm AST…moving south of Azores at 20 mph.

Analysis
Analysis of meteorological state around Hurricane Ophelia at 2 am AST. The hurricane is moving south of the Azores island chain and will pass between the Azores and Portugal Sunday morning.

This hurricane, is on track to take its already unusual path northward toward a collision course with Ireland and the United Kingdom Monday and Tuesday!

023933_5day_cone_no_line_and_wind
National Hurricane Center advisory on Ophelia and it’s path. It’s expected to reach Ireland as a “post-tropical” cyclone…a hybrid frontal system…on Monday. VERY rarely are tropical cyclones, particularly any stronger than Category 1 located in the Northeast Atlantic Ocean.

Not to worry, however. Ophelia will NOT be a tropical cyclone when it arrives in the British Isles Monday. Sunday, the hurricane will begin to pass over much cooler waters between the Azores and Portugal (and note, the hurricane is currently over waters 2-3 degrees C/~3.5-5.5 degrees F above normal). At the same time, if you look at the previous satellite analysis, the hurricane will begin to interact with the existing frontal zone and ingest air from an approaching cold air mass moving in from the North Atlantic. This will begin the process of extratropcial transition where Ophelia becomes a mid-latitude frontal system. However, because of its old, warm tropical air mass, it will continue to retain some of its internal energy, enabling it to be a powerful hurricane-force windstorm.

us_model-en-087-0_modez_2017101400_60_1642_149
European “Euro” Model showing Post-Tropical Cyclone Ophelia approaching Ireland Monday morning (AST). Other global computer models vary the center of circulation either just offshore the west shore of Ireland or make landfall over southern Ireland Monday morning.
us_model-en-087-0_modez_2017101400_63_949_379
Euro Model showing damaging wind gusts overspreading Ireland from south to north Monday. Models generally agree with bringing damaging wind gusts of 75-85 mph (~120-135 km/h) to the south and southwest coast of Ireland Monday afternoon (local time) with isolated gusts over 100 mph (~160 km/h). Gusts to 60-65 mph (97-105 km/h) with isolated higher gusts to 75 mph (120 km/hr) in the south of the island will be possible across much of the rest of the country into Northern Island Monday evening and night. All surrounding coastal waters will be hazardous for marine interests.

I have moderate confidence in my forecast…some uncertainty deals with the track of the low pressure system. A track farther offshore to the west would limit significant winds to the south and west shores and coastal communities. A track very close or even onshore the south coast would send very high winds deeper inland into Ireland. Regardless, those in the country should expect widespread downed trees, power outages, and difficult driving conditions for high-profile vehicles during the afternoon into late evening Monday.


Here is the climatological history of all known tropical cyclones in the North Atlantic just to show the rarity of systems such as Ophelia. Although some cyclones may have been missed prior to the satellite area, it is possible that such cyclones were less likely to survive in the distant past because of cooler waters where Ophelia is located now. Sea surface temperatures have warmed on Earth because of climate change.

1200px-Atlantic_hurricane_tracks
All hurricane tracks in the North Atlantic (1851-2012). Note, tracks heading to near the British Isles were likely as extratropical systems. Hurricane Vince, however, made a historic landfall as a tropical depression in southern Spain in October 2005.
GFS-025deg_NH-SAT2_SST_anom
Ophelia is over waters 2-3 degrees C above normal. The hurricane will move away from waters favorable for hurricane maintenance during the day Saturday.

–Meteorologist Nick Humphrey

GOES-16 Satellite Loop of California Wildfire Smoke

CODNEXLAB-GOES16-True-Color-23-47Z-20171011_6300-6397-1-100

The new geostationary weather satellite, GOES-16 captured this high spatio-temporal resolution loop of the smoke plume over the Bay Area of Northern California this evening before sunset. The deep smoke is embedded in the low-level north winds, while the white, high cirrus clouds are in southwesterly flow. You can right click to save or open in the new tab to see the larger version of it. It’s amazing but frightening to know what’s happening under all that smoke.

–Meteorologist Nick Humphrey

Update on Wildfire Situation in Northern California.

The Northern California wildfires continue to rage and risk both lives and property. At least fifteen fires are currently burning across Northern California with little to no containment. The most significant fires include the Atlas Fire, Tubbs Fire, the Cascade Fire, Nuns Fire, and the Redwood Complex Fire. As of 8 pm PDT, there have been 17 deaths reported (11 in Sonoma, 2 in Napa, 3 in Mendocino and 1 in Yuba Counties). 180 people have been reported missing in Sonoma County with 57 out of originally 240 reported missing found since yesterday. More than 2,000 structures have been destroyed. 115,000+ acres have been burned with many fires at 0% containment.

1024x1024 (4)
A SUV burns in the driveway of an already burned down home threatening another home in neighborhood off Fountaingrove Parkway near the Hilltop in Santa Rosa on October 9, 2017 in Santa Rosa, California. (Photo: Brian Van Der Brug/LA Times Via Getty Images).

Today, the atmospheric conditions were initially better for fighting fires this morning with higher humidity values and low winds. Winds have remained lighter today compared to previous days, but humidity has once again dropped this afternoon below 30% or even 20% in many areas in the hilly elevated terrain down into Napa Valley, allowing fires to continue to steadily spread.

Humidity
Low humidity values north of the Bay Area allowing fires to more easily attack vegetation and structures. (earth.nullschool.net).
Particulates
Very high surface particulates causing very poor to hazardous air quality over much of Northern California (particulate matter on map <2.5 micrometers). (earth.nullschool.net).

I wish there was more good news to give to the folks in NorCal, but unfortunately, NO rain is forecast for the region for the next seven days. In addition, the National Weather Service issued a RED FLAG WARNING for Wed Night-Thurs Afternoon as high easterly winds blowing out of the hilly terrain will produce very low humidity, allowing for potentially explosive wildfire growth.

us_model-en-087-0_modusahd_2017101018_38_5247_149
Global Forecast System model forecast valid 1 am PDT Thursday morning showing high pressure building over the elevated terrain of Nevada and northeast California. Strong easterly downsloping winds will develop, intensifying wildfire potential.
us_model-en-087-0_modusahd_2017101018_38_5247_211
Global Forecast System model forecast valid 1 am PDT Thursday morning showing wind gusts of 25-45 mph across north-central California.
us_model-en-087-0_modusahd_2017101018_38_5247_219
Global Forecast System model forecast valid 1 am PDT Thursday morning showing humidity values falling below 25%, keeping fuels dry for fires to spread.

If you know anyone in or near the effected region (or in the RED FLAG WARNING areas), tell them to make sure they clear vegetation near their homes/businesses and have an emergency plan in case evacuations are issued for their area. Unfortunately, this wildfire disaster is ongoing and requires those who are in or near rural country to be ready to escape at a moment’s notice.

Live Updates by the San Francisco Chronicle: HERE

—Meteorologist Nick Humphrey

Firestorm devastating portions of Napa Valley, CA.

Sunday Night, major fires erupted in California’s Napa Valley under strong easterly winds and low relative humidity. This resulted in a conflagration engulfing communities and homes in flames and forcing thousands to make quick escapes in the early morning hours. One of the worse hit communities is Santa Rosa, where much of the city has been destroyed by fire. Over 1500 homes and businesses are believed to have been burned down in the Napa Valley region. The flames continue to grow at this time with over 75,000 acres burned.

Photos via the San Francisco Chronicle.

The fires are occurring in a region which is currently not in drought conditions hydrologically (as of last Thursday). However, after an unusually wet winter, an unusually hot, dry season followed. This allowed fuels, which grew in abundance following the wet season to dry out, leading to the massive fires in CA in this summer going into the Fall. Much of Western North America has been suffering significant fires in 2017 (year-to-date acreage burned in the US, as of Friday, was 3rd to 2012 and 2015). Intensifying wildfire seasons (on regional/continental scales) and increasing frequency of large fluctuations in extremes between very wet and very dry periods are predicted signals of climate change from global warming as well.

january-to-march-2017-us-total-precipitation-percentiles-map
Much above average to record precipitation in Northern California in January-March 2017.
august-2017-us-total-precipitation-percentiles-map
Much below average to record minimum precipitation (including NO measurable rain) in Northern California in August 2017. June-August 2017 saw much below average precipitation.
august-2017-us-average-temperature-percentiles-map
Much above average and record warmth across the West Coast during August 2017. San Francisco Bay Area saw record highs over 100 degrees at the start of September.

So far the fires have killed 10 people (as of 10 pm PDT Monday Night), while more than 110 have been injured, some severely from burns, most from smoke inhalation. It’s being reported Monday Night that 100 missing persons reports have been called in to the Sonoma County, CA office.

920x1240
Region where fires are in progress in the San Rosa and Napa region far north of San Francisco and west of Sacramento.

Although relative humidity conditions will improve somewhat tomorrow, no rainfall is forecast for this region of Northern California for the next 7 days to dampen the fire situation. Winds Tuesday will likely gust over 20 mph and may be locally stronger near the fire, continuing the self-sustaining burn.

us_model-en-087-0_modusarpd_2017101004_2_1900_219
11 pm PDT Monday Analysis by the High-Resolution Rapid Refresh (HRRR) showing the low dew point temperatures near and east of Santa Rosa. This area delineates a region of low relative humidity, allowing fires to burn and spread with little moisture on fuels to slow their extent.

 

For further updates see this updating page by the San Francisco Chronicle.

–Meteorologist Nick Humphrey