1. Early Hurricane Notes ATS 553

3. Hurricane Classification TROPICAL WAVE: –A trough or cyclonic curvature maximum in the tradewinds

4. Hurricane Classification TROPICAL DISTURBANCE: –A discrete system of apparently organized convection maintained for a day or more

5. Hurricane Classification TROPICAL STORM: –A warm core tropical cyclone with closed isobars, rotary circulation, and winds between 34 and 64 knots. –WHEN THEY GET THEIR “NAME”

6. Hurricane Classification HURRICANE/TYPHOON: –A warm core tropical cyclone with closed isobars, rotary circulation, and winds of at least 64 knots. –Does not necessarily have an eye, but often does.

7. Characteristics: TDTSH SFC winds<= 34 kt<= 64 kts> 64 kts Avg. SFC P1000mb990mb960mb Vis. FeaturesNo eye/wall May have eye Wind shear> 15 kts< 15 kts0 VortexCyclonic throughout Anticyclonic above 300mb Active convection < 1%1%4-5% 500mb TColder than environment Warmer than environment

8. Naming Hurricanes In the Atlantic: –A, B, C, D… –Alternate boy-girl –Rotate through six lists –Retire names for especially damaging storms

10. Eastern Pacific Very similar scheme as in the Atlantic

11. Western Pacific Just uses a long list In alphabetical order BY THE COUNTRY THAT SUBMITTED THE NAME Names can be retired, too.

12. Western Pacific typhoon names Names in the five lists below are used sequentially from year to year IIIIIIIVV Contribute d by Name CambodiaDamreyKong-reyNakriKrovanhSarika ChinaLongwangYutuFengshenDujuanHaima DPR KoreaKirogiTorajiKalmaegiMaemiMeari Hong Kong, China Kai-takMan-yiFung- wong Choi-wanMa-on JapanTembinUsagiKammuriKoppuTokage Lao PDRBolavenPabukPhanfoneKetsanaNock-ten Macau, China ChanchuWutipVongfongParmaMuifa MalaysiaJelawatSepatRusaMelorMerbok MicronesiaEwiniarFitowSinlakuNepartakNanmadol Philippine s BilisDanasHagupitLupitTalas RO KoreaKaemiNariChangmiSudalNoru ThailandPrapiroonVipaMegkhlaNidaKularb U.S.A.MariaFranciscoHigosOmaisRoke Viet NamSaomaiLekimaBaviConsonSonca CambodiaBophaKrosaMaysakChanthuNesat ChinaWukongHaiyanHaishenDianmuHaitang DPR KoreaSonamuPodulPongsonaMindulleNalgae Hong Kong, China ShanshanLinglingYanyanTingtingBanyan JapanYagiKajikiKujiraKompasuWashi Lao PDRXangsaneFaxaiChan-homNamtheunMatsa Macau, China BebincaVameiLinfaMalouSanvu MalaysiaRumbiaTapahNangkaMerantiMawar MicronesiaSoulikMitagSoudelorRananimGuchol Philippine s CimaronHagibisImbudoMalakasTalim RO KoreaChebiNoguriKoniMegiNabi ThailandDurianRamasoonHanumanChabaKhanun U.S.A.UtorChataanEtauKodoVicente Viet NamTramiHalongVamcoSongdaSaola

13. Western Pacific typhoon names Names in the five lists below are used sequentially from year to year IIIIIIIVV Contributed by Name CambodiaDamreyKong-reyNakriKrovanhSarika ChinaLongwangYutuFengshenDujuanHaima DPR KoreaKirogiTorajiKalmaegiMaemiMeari Hong Kong, China Kai-takMan-yiFung-wongChoi-wanMa-on JapanTembinUsagiKammuriKoppuTokage Lao PDRBolavenPabukPhanfoneKetsanaNock-ten Macau, China ChanchuWutipVongfongParmaMuifa MalaysiaJelawatSepatRusaMelorMerbok MicronesiaEwiniarFitowSinlakuNepartakNanmadol PhilippinesBilisDanasHagupitLupitTalas RO KoreaKaemiNariChangmiSudalNoru ThailandPrapiroonVipaMegkhlaNidaKularb U.S.A.MariaFranciscoHigosOmaisRoke Viet NamSaomaiLekimaBaviConsonSonca CambodiaBophaKrosaMaysakChanthuNesat ChinaWukongHaiyanHaishenDianmuHaitang DPR KoreaSonamuPodulPongsonaMindulleNalgae Hong Kong, China ShanshanLinglingYanyanTingtingBanyan JapanYagiKajikiKujiraKompasuWashi Lao PDRXangsaneFaxaiChan-homNamtheunMatsa Macau, China BebincaVameiLinfaMalouSanvu MalaysiaRumbiaTapahNangkaMerantiMawar MicronesiaSoulikMitagSoudelorRananimGuchol PhilippinesCimaronHagibisImbudoMalakasTalim RO KoreaChebiNoguriKoniMegiNabi ThailandDurianRamasoonHanumanChabaKhanun U.S.A.UtorChataanEtauKodoVicente Viet NamTramiHalongVamcoSongdaSaola

14. Other Basins Use other schemes Usually just short lists that they rotate through as needed

15. Historically: Prior to WWII, storms were named after the patron saint of the day. Post WWII, various schemes: –Phonetic alphabet (alpha, bravo, charlie..) –Animals (Antelope, Bear, Cat, Dog…) –Adjectives (Aggressive, Blusterly…) –All Female Names starting in the mid 1950s –Male names started in 1979

16. Tropical Cyclones vs. Midlatitude Cyclones Strongest Winds: –MC: Jet Stream –TC: Surface

17. Tropical Cyclones vs. Midlatitude Cyclones Core Temperature: –MC: Cold core (trough) –TC: Warm core (LHR in eyewall, subsidence in eye)

18. Tropical Cyclones vs. Midlatitude Cyclones Structure: –MC: Asymmetric, fronts –TC: Symmetric, no fronts

19. Tropical Cyclones vs. Midlatitude Cyclones Scale: –MC: Synoptic scale –TC: Mesoscale in size, synoptic scale in duration

21. Why Winds Decrease With Height In A Hurricane ATS 553

23. Warm Core Systems

24. Temperature Gradient!

25. From Above…

28. What if this were a regular warm front? What would the Thermal Wind relationship tell us about how winds would be changing with respect to height?

29. What if this were a regular warm front? Wind speeds at the surface would be weak. Aloft, there would be a Midlatitude Jet Stream! Winds would be getting more positive with height!

30. What if this were a regular warm front? Wind Speed Height 0

31. But This Is NOT a Midlatitude Cyclone

33. Strong Surface Winds

34. With height, these winds DECREASE due to the Thermal Wind Relationship!

35. Strong Surface Winds…

36. …get weaker with height…

37. …even reverse aloft..

38. …to create the upper-level anticyclone!

39. Wind Profile: Wind Speed Height 0

40. Hurricane Cookbook 1. High SSTs (at least 26°C) –Flux of sensible and latent heat –Hurricanes do NOT “seek out” warm water

41. Hurricane Cookbook 2. Coriolis Force (at least 5° off of the equator) –Hurricanes are in CYCLOSTROPHIC balance, not GEOSTROPHIC BALANCE –However, Coriolis Force keeps the winds from just following directly into the region of low pressure when it first forms. –Hurricanes don’t FORM at the equator. –Hurricanes don’t CROSS the equator!

42. Hurricane Cookbook 3. Instability –Rules out subtropical highs, which are regions of sinking motion and high stability –KNOW WHY SINKING MOTION IS ASSOCIATED WITH INCREASED STABILITY!

43. Hurricane Cookbook 4. No wind shear –Redistributes vertical profile of latent heat release, setting up the wrong circulation patterns –TUTT—Tropical Upper Tropospheric Trough

44. TUTT– June thru August

45. Hurricane Cookbook 5. High relative humidities through midlevels of the troposphere –Helps reduce the impact of entrainment. –Individual Cumulus towers are easily destroyed by entrainment of dry air.

46. Hurricane Cookbook 6. An initial disturbance –Unorganized groups of thunderstorms organize into tropical storms. –Typically these are West African Squall Lines or other disturbances in the AEJ.

47. Saffir-Simpson Scale