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:

 

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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.

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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.
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Quick update on Northern California Wildfires (plus weather forecast)

As of now (5:30 pm PDT), the death toll in the California Wildfires is up to 35 and is expected to go up further. 18 in  Sonoma County, 9 in Mendocino County, 4 in Yuba County and 4 in Napa County. 5700 structures have been destroyed and 221,000 acres have been burned. Treating the conglomeration of fires as a single event (as all the Northern CA ones initiated Sunday Night), this is by far the most destructive fire event in state history and one of the deadliest. Simply horrifying and very sad.

Firefighters have begun to have some containment success the past 48 hrs with slower winds and at least some periods of slightly improved humidity. However, tonight-Sunday morning will feature an intensification of extreme fire danger. This is because a strong surface high pressure system will advance toward the central Intermountain West this weekend, intensifying downsloping Diablo winds from the hilly and foothill mountainous terrain of Northern California. North-northeast winds may gust as high as 45-60 mph Saturday, inducing very low humidity values, drying out fuels and potentially promoting extreme fire behavior (high forward speed, rapid growth) in existing fires as well as any new fires. Red Flag Warnings have been issued by the National Weather Service to cover this forecast potential.

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Strong high pressure moving over OR, ID and NV Saturday will promote strong Diablo winds over Northern California. (NWS forecast surface map valid 11 am PDT Saturday).

There are no thunderstorms forecast, so any new fires would be likely started by human activity. So folks in these areas need to very much be careful with anything which can potentially start fire and really…just avoid starting any outdoor fire or using  anything which sparks.

Some good news…mid-range computer model forecasts suggest a pattern shift toward precipitation and cooler weather by the end of next week. Just have to get through the next week of fire activity before some meaningful hydrologic relief to aid the firefighting efforts.

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The Global Forecast System Model forecast accumulated total precipitation valid 8 pm PDT Friday. This is one forecast scenario, but all global models point toward a wetter pattern, beginning the second half of next week into next weekend.

–Meteorologist Nick Humphrey

California Fire Crisis (Wed Updates)

Update at 11:15 pm PDT Wed:

The Wine Country Fires in Northern California have now destroyed over 3500 structures, making it the most destructive fire event in state history. And with 23 deaths now reported, it is quickly approaching the record for the deadliest. There are still areas burned where police have yet to search for potential victims because the primary operations are focused on evacuations and maintaining safety in the current fluid situation. Unfortunately, given that the missing persons are over 280, even with many being found safe, the death toll is still likely to go up as some are found.

Amazing the disturbing level of destruction of this fire event. I was only 7 yrs old in 1991, but I remember the Oakland Hills Firestorm, as it was plastered all over the news as much as this event. I didn’t think I could imagine such a disastrous fire worse than that.

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Update at 5:30 pm PDT Wed: Update on the Meteorological Conditions in the Bay Area/Napa Valley Region.

Numerous fires continue to largely out of control over the Napa Valley/North Bay region. Heavy Smoke (with particulate matter >2.5 micrometers) is spreading southward over the Greater Bay Area reducing visibility and causing air quality to be considered very unhealthy for all individuals in the region with VERY UNHEALTHY conditions in the hilly terrain east of Santa Rosa and Oakland. If you can stay indoors, do so, especially for the young, elderly, and those with chronic breathing problems.

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Particulates
Particulate smoke (<2.5 micrometers) being produced by the fires and spread southward from northerly winds. This is causing very poor air quality across the state of CA. (earth.nullschool.net)

A RED FLAG WARNING REMAINS IN EFFECT FOR MUCH OF N. AND C. CALIFORNIA FROM NOW UNTIL TOMORROW AFTERNOON. As high pressure builds across Oregon into NE. Nevada, easterly downsloping winds will intensify the foothills across the interior of Northern CA, increasing the threat for any fires which develop to spread quickly and existing fires to expand acreage quickly. These winds will help maintain very conditions longer into the night, slowing humidity recovery and allowing fires to potentially exhibit extreme behavior (heat, forward speed, self-maintenance). Winds may gust up to 45-50 mph in some areas.

Map
High-Resolution Rapid Refresh (HRRR) Model forecast for around 10 pm PDT showing the intensifying pressure gradient and pressure ridging over the hills and mountains of northern CA. This will lead to development and intensification of dry Diablo winds overnight.
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The HRRR forecast valid for 1 am PDT showing widespread dew point temperatures in the mid-20s. With temps in the mid/upper-50s, this means humidity values in the 25-35% range, keeping fuels relatively dry for spreading fire in the face of 40-50 mph wind gusts near the foothills.

These fires have largely been a result of 1) the 5 yr extreme drought weakening trees 2) the very wet winter producing abundant brush growth 3) extreme hot, dry summer drying out all fuels.

New evacuation orders have already come out for some areas, including the City of Calistoga (northeast of Santa Rosa) where the entire town of over 5,000 are being told to leave. See the Impact Statement at the bottom of this post…but folks need to be ready to evacuate if necessary at a moment’s notice.

–Meteorologist Nick Humphrey

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CalFire has updated news at 11:30 am PDT and now say 21 people have been confirmed killed and 172,000 acres have now burned across the entire state. The most destructive fires are in North-Central California north of the Bay Area, but the Canyon 2 Fire continues to menace Anaheim in Southern California.

A RED FLAG WARNING is in effect for much of the interior valleys and foothill terrain of California.


This is for extreme fire danger today – Thursday. As high pressure builds this evening and tonight over Nevada and east of the Sierra Nevada Mountains, a NE-SW pressure gradient will intensify, leading to strong downslope winds known as Diablo winds or Santa Ana Winds (the former in Northern CA, the latter in Southern CA). These winds will gust potentially 40-45 mph+. In addition, because they are downsloping, the air undergoes adiabatic warming…warming caused by the air compressing as it flows down toward higher vertical pressure at lower elevations. The air not only warms, but also dries out, turning winds blasting out of canyons into a hot blow dryer…drying out fuels and allowing a fire to turn into a firestorm.

IMPACT STATEMENT:

I CANNOT STRESS ENOUGH…if you live in areas under the red flag warning or if you know anyone who lives in these areas, especially near the urban-wildland interface…please have a plan of what to do if a mandatory evacuation is ordered for your area and have a way to get warnings. ESPECIALLY AT NIGHT. Stay in contact with friends/relatives, have someone stay up to watch tv or listen to radio, keep your phone on and charged, have a weather radio. Most importantly, make sure those smoke detectors are working as they may be a final warning of danger impacting your home at night. These fires may intensify or new ones may start Wed night-Thurs morning because of strengthening winds and the humidity…which normally increases at night…may not do so because of the very dry nature of the winds. This will allow for potentially explosive fire behavior. And please, be smart with anything related to flammable materials and clear any brush away from your home if possible, to give you more time if a fire does approach.

I really hope the situation does not worsen significantly. Fires are scary events and incredibly destructive. Please be safe and be ready if you are in these areas.

I’ll have updates on this page throughout today and tonight.

–Meteorologist Nick Humphrey

 

Global Climate Change and its Potential Connection to Hurricane Activity (cited research)

Because of recent North Atlantic Hurricane Season activity…many people have questioned whether hurricanes are becoming stronger and more numerous because of climate change. In the social media universe, I’ve seen many opinionated debates within the general public, as well as meteorologists and perhaps a few sprinkling of climatologist opinions here and there. Not to mention, interesting statements from non-climate scientists. What I have not seen much, however, is any discussion of peer-reviewed research on the topic. There’s so much knowledge being gathered every year by scientists trying to answer important questions about our past, present and future. How climate change will impact regional weather and climates is one of the most important questions because of potential impacts to people, agriculture and natural resources.

I decided to do a (very brief) search of literature on science’s current understanding of climate change as it relates to tropical cyclones. I looked into both the potential connection of global warming to these events in the current climate (attribution), as well as projections for these events based on the “business-as-usual” scenario for carbon dioxide emissions, which is a high emissions scenario and steady increase in CO2 concentration. Research cited are just a sampling of what’s out there and what I looked over. Here are some themes I found interesting (takeaway statements at the end):

Climate models* appear to show a signal toward more intense (Category 4-5 Saffir-Simpson) tropical cyclones overall in the world by the latter half of the 21st century. However, there is also a potential for a downward trend in cyclone numbers in many basins (see #1-4).

The decrease in overall cyclone numbers by the second half of the century is thought to be a product of increasing vertical wind shear over tropical oceans limiting weaker storms. However, many researchers expect there to be a significant upward trend in more intense storms (Category 4-5) as the oceans continue to warm and tropical cyclone formation and track density moves poleward. So formerly less favorable sub-regions of basins may see an overall increase in cyclone activity (with more storms which will be stronger than before in those regions) and in the increasingly less hospitable regions (over the long term), storms which do form when conditions are favorable on short time scales may see cyclones which are also more intense than in years past.

As for historical conditions leading to the present…there does not appear to be a conclusive signature by global warming on tropical cyclone intensity outside of natural variability on a global scale (3-4). However, some regional signals related to frequency changes are being actively studied. 

There is some suggestion (4) based on modeling past climate change to the present time that warming (which would enhance the potential intensity for hurricanes) has been muted by the industrial production of aerosols (particulates like sulfates and nitrates), which actually reflect sunlight from reaching Earth’s surface. However, as warming continues into mid-century, its effect of trapping heat will begin to significantly exceed aerosol cooling effects leading to the more pronounced impacts on cyclone intensity stated earlier (unless CO2 emissions are significantly reduced soon). So while global warming is happening in the background, hurricane potential intensity as we currently witness it is likely still being dominated by natural cycles. (For more on climate change research into tropical cyclones, you can also see this webinar done by climate change researcher Dr. Kerry Emanuel for Climate Central).

With that said, some researchers see signs of a global warming signature associated with recent increased tropical cyclone *frequency* in sub-regions of basins. These include the far eastern portion of the North Atlantic Basin (4), close to the East Asian Coast (5), and a portion of the North-Central Pacific Basin (6). Research is still ongoing on global warming’s past and future influence on activity in individual tropical cyclone basins.

Meanwhile, there is evidence of other impacts related to tropical cyclones (and other significant weather phenomena) and climate change. These include higher rainfall rates (7) and higher storm surge related to sea-level rise from the melting polar ice sheets and thermal expansion of the oceans (8). In addition, there is some scientific evidence that tropical cyclones in recent decades have begun to intensify more rapidly because of increased ocean warming (9). And while not completely clear yet whether it is fully tied to climate change, it is known that the observed North Atlantic Power Dissipation Index (PDI) has increased significantly since the mid-1970s (10; positively correlated to sea surface temperatures) and globally, the strongest tropical cyclones in respective basins have grown stronger since 1981 (Elsner et al, 2008…not included here). Note that scientific critics point out the use of observational data with differences in quality – satellite intensity estimates and reconnaissance flights (or lack of them) – over recent decades could put some uncertainty in these results.

My thoughts? Although inconclusive, possible intensity signals may be a hint of the projected effects of climate change as PDI and high-end cyclone intensity are highly correlated to sea surface temperatures. SSTs are increasing from global warming and this would connect with what climate models suggest of future tropical cyclone activity, if these historical trends are, in fact partially related to climate change.

The Takeaways:

  1. Tropical cyclone intensity at the highest end of the scale appears likely to increase through the 21st century because of climate change, especially if human civilization does not significantly reduce greenhouse gas emissions soon.
  2. While a current climate change signal to intensity is difficult to detect and still a matter of debate, storms in recent decades appear to be intensifying faster, are capable of producing more extreme precipitation events and higher storm surges because of rising sea levels caused by ice sheet melting and thermal ocean expansion. There also appears to be some detectable changes in frequency of storms within individual basins which may locally enhance risk.
  3. Regardless of the exact changes in frequency and intensity of tropical cyclones, the risks to individuals and society because of climate change will increase into the coming decades. It will be important for people and governments to make decisions (beyond greenhouse gas emissions) related to property, coastal land use and emergency management policy to mitigate increasing tropical cyclone hazards, particularly from water (storm surge/inland flooding).

Note: It is of EXTREME importance that those with a desire to communicate climate change issues try to inform our fellow citizens to the best of our ability. Climate change is one of the important issues facing our world (the impact on the global food supply and human health may be actually of greatest importance, but rarely discussed as those aren’t “sexy” topics…). People have their thoughts on the issue based on experiences, politics, religious/spiritual beliefs, etc. However, at the end of the day, we must inform and connect what we know to people’s concerns and allow people to decide as they may. Without censorship (“We can’t discuss climate change right now!”) or nonsensical exaggerations (“So many hurricanes, it’s a new era of superstorms!”). Stay informed (give informed opinions) and tell people why they should care as it relates to their lives. Like everything else we should communicate to the concerns of people. Considering most Americans are now, in fact, concerned about climate change, there’s really NO excuse not to discuss the issue in a serious, informed manner if we have the interest to discuss it at all. 


Additional Note: *-Climate models are not weather forecast models. They do not forecast the atmosphere using initial conditions, but take a climate state (for example, our current climate) and adjust “forcings” on the climate system (carbon dioxide emissions for example). The effect of these changes to “boundary conditions” over time are interpreted for land, sea, the cryosphere and (for Earth System models), the biosphere. Global climate is based on thermodynamic and hydrologic balances which will look for equilibrium when changes to a part of the system are applied. (For more on climate models you can see this webinar by Research Meteorologist Keith Dixon of NOAA’s Geophysical Fluid Dynamics Laboratory for Climate Central).

References (links are PDFs):

#1 – Bell et al. (2013)

#2 – Murakami et al. (2011)

#3 – Wang and Wu. (2013)

#4 –  Sobel et al. (2016)

#5 – Cheng-lin et al. (2016)

#6 – Murakami et al. (2015)

#7 – Knutson et al. (2013)

#8 – Jevrejeva et al. (2016)

#9 – Kishtawal et al. (2012)

#10 – Emanual (2005)

—Meteorologist Nick Humphrey

Update on Hurricane Maria (2:30 pm EDT). High winds and flooding rains impacting Puerto Rico.

Hurricane Maria is beginning to emerge from the island of Puerto Rico after the center made landfall 8 1/2 hrs ago as a Category 4 storm with max winds of 155 mph (Cat 5 is 156+ so catastrophic wind speeds occurred). 

The hurricane is now a Category 3 storm with 115 mph sustained winds and gusts over 130 mph near the center. Damaging winds and torrential flooding rains will continue for the rest of the afternoon as the system continues to push out into open ocean water.


Most computer models indicate the system should remain offshore the United States as it moves north in a weakness in the upper level higher pressure field caused by the presence of Tropical Storm Jose offshore the Mid-Atlantic and southern New England.

 
The crucial timing to be rid of Maria forever will be the approach of a significant upper level trough of low pressure from the Midwest midweek next week to “kick” the dying hurricane out to sea. Most models show this connection keeping the system offshore being, however there is higher variability in the track after Monday which could bring the system closer to shore than expected. Currently, I feel direct impacts…the tropical storm force wind field and significant rain bands…will likely (66%+ probability) stay offshore. But potential variability makes the situation worth watching closely. 

Regardless, high surf and rip currents (currents which pull water offshore and make swimming dangerous) are likely by early next week. The system will also be weaker offshore the East Coast thanks to less intense sea surface temperatures and increasing vertical wind shear from mid-latitude winds.

In the meantime, direct impacts from a Cat 3-4 storm are likely for north coast of the Dominican Republic, the Turks and Caicos Islands and the southern Bahamas. Hurricane warnings are in effect for all these areas. 

–Meteorologist Nick Humphrey

Update on Hurricane Maria (9:25 am EDT). Catastrophic flash flood/violent wind event ongoing.

Maria made landfall as a powerful Category 4 storm near Yabucoa, PR with maximum sustained winds of 155 mph and minimum central pressure of 917 millibars (at 6:35 am EDT). The hurricane continues to move across the island delivering destructive hurricane force winds and torrential amounts of rain leading to massive flash flooding (including 5-7 inch/hr rainfall rates).

The storm currently has max winds of 145 mph. 

River gauges across PR are rising incredibly fast from the high rainfall rates:


Radar near time of landfall (currently offline):

Update on Hurricane Maria (6:30 am EDT)

#Maria is making landfall in eastern Puerto Rico as a Category 4 Hurricane with maximum sustained winds of 155 mph. Gusts of 160+ are likely in progress over northeast coast of PR. Catastrophic weather conditions will continue to spread across the island over the next couple of hours. 

Terrible situation for the 3.5 million people hunkering down this morning. 

PR Radar failed just before 6 am EDT. More inbound winds of 155 mph or higher as eyewall moved over radar site (which is in elevated terrain and winds likely much stronger).