Temperature & Wind

⚠️ Heat Index Chart

Survival Tips

• 🚰 Drink water every 15-20 minutes, even if not thirsty
• 🏠 Stay indoors during peak hours (10am-4pm)
• 👕 Wear loose, light-colored, breathable clothing
• 🚗 NEVER leave children or pets in parked vehicles
• 🧊 Apply cold water to wrists and neck

Lethal Combinations

• 40°C + 75% humidity = 35°C WBT (fatal)
• 45°C + 50% humidity = 35°C WBT (fatal)
• 50°C + 26% humidity = 35°C WBT (fatal)
• 50°C + 20% humidity = 30°C WBT (survivable with caution)

Regions Approaching Limit

• 🌍 Persian Gulf (already hit 34.6°C WBT)
• 🌍 Indus Valley, Pakistan
• 🌍 North China Plain
• 🌍 Amazon Basin (humidity + heat)

By 2100 Projections

Without emissions cuts, parts of South Asia, Middle East, and Gulf may regularly exceed 35°C WBT, making outdoor labor impossible and displacing millions.

Why It's Deadly

• 🌙 Nighttime temps stay high (no recovery)
• 📈 Cumulative heat stress builds daily
• ⚡ Power grid overload from A/C demand
• 🌾 Crops wilt rapidly, livestock die
• 🔥 Extreme wildfire conditions

Climate Change Link

Heat domes are becoming more frequent, intense, and longer-lasting due to climate change. The jet stream is weakening, allowing high pressure systems to stall for longer periods.

Mitigation Strategies

• 🌳 Urban tree planting (shade + evapotranspiration)
• ⬜ Cool roofs (white/reflective surfaces)
• 🌿 Green roofs and vertical gardens
• 💧 Permeable pavements
• 🏞️ Urban parks and green corridors
• 💨 Building orientation for wind flow

Hottest US Cities (UHI Effect)

New Orleans, Newark, New York, Houston, and San Francisco experience the strongest UHI effects. Phoenix, despite being desert, has a UHI up to 6°C at night.

Formation Mechanism

• Rain falls from a dying thunderstorm
• Rain evaporates in dry air below cloud
• Evaporation cools the air, making it dense
• Dense air plunges to ground rapidly
• Compression heats the air dramatically (adiabatic heating)
• Result: sudden hot, dry, gusty wind at surface

Dangers

Can damage crops, stress livestock, and create sudden fire weather conditions. Often mistaken for instrument errors due to how extreme the readings are.

Why It Suppresses Hurricanes

• Extremely dry air (humidity often <30%)
• Dry air disrupts the moist convection hurricanes need
• Dust particles = poor cloud condensation nuclei
• Wind shear within SAL tears apart developing storms

Amazon Connection

About 27 million tons of Saharan dust reaches the Amazon annually, providing phosphorus that fertilizes the rainforest. Without it, the Amazon would be nutrient-poor.

Wind Chill Chart

Frostbite Timeline

• -10°C to -27°C: 30+ minutes exposure
• -28°C to -39°C: 10-30 minutes exposure
• -40°C to -47°C: 5-10 minutes exposure
• Below -48°C: Under 5 minutes exposure

Sudden Stratospheric Warming

When the stratosphere over the Arctic suddenly warms (up to 50°C in days), it can split or displace the polar vortex, sending frigid air toward lower latitudes.

Why It's Happening More

• Arctic warming reduces temperature gradient with mid-latitudes
• Weaker gradient = weaker jet stream
• Weaker jet stream = more "wavy" patterns
• Wavy jet stream = cold air escapes south more easily

"Snowbelt" Cities

• 🇺🇸 Buffalo, NY (Lake Erie) - 240 cm/year
• 🇺🇸 Syracuse, NY (Lake Ontario) - 310 cm/year
• 🇺🇸 Cleveland, OH (Lake Erie) - 170 cm/year
• 🇺🇸 Marquette, MI (Lake Superior) - 380 cm/year
• 🇨🇦 Owen Sound, ON (Georgian Bay) - 340 cm/year

Key Requirements

• Lake-air temp difference of 13°C+ needed
• Long fetch (distance wind travels over water)
• Unfrozen lake surface
• Climate change = less ice = more lake-effect snow (for now)

Experience

• 💥 Sound like gunshot, thunder, or explosion
• 🏠 Can shake houses and wake people up
• 🌍 No seismic signature on earthquake monitors
• ✅ Cannot damage structures (too shallow/small)

Where They Occur

Common in Canada, northern US, and Scandinavia. Typically happen in late night when temperatures plunge fastest. Often occur multiple times during one cold snap.

Optical Effects

• ☀️ Sun halos (22° rings around sun)
• 🌟 Sun pillars (vertical light columns)
• 🔮 Sundogs (bright spots beside sun)
• ✨ Glitter effect on ground surface

Where to See It

Common in Antarctica, Arctic regions, and interior continental areas in winter. The ice crystals are tiny hexagonal plates that act as millions of tiny prisms.

Formation Requirements

• Strong temperature contrast (cold continent, warm ocean)
• Upper-level jet stream support
• Most common over northwestern Atlantic and Pacific
• Peak season: October through March

Notable Events

• 2018 Nor'easter: 59 mb drop in 24h
• 2019 Central US: -24 mb in 24h, 100+ mph winds
• 2022 Christmas: Killed 50+ in US, -40°C in some areas

Formation

High pressure over Great Basin pushes air westward. Air compresses and heats as it descends through mountain passes, arriving hot, dry, and gusty.

Fire Connection

• Most destructive CA wildfires occur during Santa Anas
• Camp Fire (2018), Woolsey Fire, Thomas Fire
• Embers can travel miles ahead of fire front

The Science

• Moist air rises on windward side, cools at ~6°C/km
• Moisture condenses, releasing latent heat
• Now-dry air descends leeward side, warms at ~10°C/km
• Result: air arrives warmer than it started

Other Names

Zonda (Argentina), Nor'wester (New Zealand), Canterbury Arch (NZ), Puelche (Chile), Austru (Romania).

Cultural Impact

• Provençal saying: "Mistral blows 3, 6, or 9 days"
• Van Gogh painted during Mistral, claimed it affected his art
• Traditional architecture oriented to block wind
• Named for "magistral" (masterly/dominant)

Regional Names

• 🇮🇹 Scirocco (Italy)
• 🇪🇸 Xaloc or Jaloque (Spain)
• 🇭🇷 Jugo (Croatia)
• 🇲🇹 Xlokk (Malta)

Health Effects

Associated with lethargy, irritability, and headaches. Italian courts historically considered Sirocco as a mitigating factor in crimes of passion.

Extreme Effects

• Sea spray freezes on ships, buildings, roads
• Ships have capsized from ice buildup
• Trieste, Italy: chains installed for pedestrians
• Can blow cars off roads

Two Types

"Svetla bura" (bright bora) - clear skies, sunshine. "Tamna bura" (dark bora) - cloudy with precipitation.

Health Effects

• Cracked lips and dry skin common
• Respiratory issues from dust
• Eye irritation widespread
• Positive: suppresses mosquitoes, reduces malaria

Regional Impact

Called "the doctor" because it provides relief from humid heat. Airports frequently close due to visibility below minimums.

Safety

• 🚗 Pull off road completely, turn off lights
• Keeping lights on may cause rear-end collisions
• Cover nose and mouth
• Duration typically 10-30 minutes

Etymology

From Arabic "habūb" meaning "blowing furiously." The term was adopted in Arizona after a 2011 storm, though some locals resist the Arabic name.

Antarctic Katabatics

The ice sheet acts as a giant cold reservoir. Cold air flows continuously toward the coast, accelerating as it funnels through valleys. Cape Denison averages 80 km/h winds year-round.

Examples Worldwide

• Piteraq (Greenland) - can exceed 300 km/h
• Oroshi (Japan) - cold mountain wind
• Santa Ana - warm katabatic variant
• Williwaw (Alaska) - sudden violent gusts

Sea Breeze Front

The leading edge of sea breeze air can trigger thunderstorms. In Florida, colliding sea breezes from both coasts meet in the center, creating the state's famous afternoon thunderstorms.

Timing

• Sea breeze starts: 10am-noon, peaks afternoon
• Calm transition: around sunset
• Land breeze starts: 2-3 hours after sunset
• Land breeze weaker than sea breeze