Notes From 9/26 - 10/17
Notes From 9/26 - 10/17 GEOG 1112
Popular in Intro to Weather and Climate
verified elite notetaker
Popular in Geography
This 5 page Study Guide was uploaded by Kaley Notetaker on Tuesday October 18, 2016. The Study Guide belongs to GEOG 1112 at University of Georgia taught by Dr. Elgene Box in Fall 2016. Since its upload, it has received 6 views. For similar materials see Intro to Weather and Climate in Geography at University of Georgia.
Reviews for Notes From 9/26 - 10/17
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/18/16
10/10 - wasn’t in class; notes to come here on study guide. 10/12 Hurricanes Tropical weather: polar outbreaks, easterly waves, etc. Requirements for hurricane development Hurricane components and development Hurricane anatomy: eye, wind speed, outflow Hurricanes and coastlines: storm surge Hurricane tracks Hurricanes vs. Tornadoes P.76 – Tropical Weather Tropical Weather particular features: 1) Polar Outbreaks – cold fronts which move into the tropics; such fronts usually bring thunderstorms but can also be “dry” cold fronts, they are followed by clear skies 2) Weak Equitorial Lows – localized lows but part of the more general Intertropical Convergence Zone. Even in the ITC, pressure is variable. Areas of lower pressure may be generated over areas of greater surface area 3) Easterly Waves – Parallel bands of alternating high and low atmospheric pressure (common starting point for hurricanes!!!) Since coriolis is weak in the tropics, highs and lows are often linear rather than circular, the trough (low pressure) brings a day or two of showers and the ridge (high pressure), a day or two of clearer skies - Form in conditionally unstable air over warm ocean surface - Form long waves (2000 km or longer) in trade winds - Travel slowly; requiring 4-5 days to pass a place completely Hurricane Requirements and Structure: Hurricane: a low pressure vortex; driven by latent heat liberated during condensation (sometimes called a “heat engine”) ; driven differently than tornado Requirements: 1. Continuous supply or warm, wet air (mT air, at least conditionally unstable) 2. A pre-existing surface low-pressure center (at which to start) 3. Coriolis (i.e. cannot start at equator) **different than tornadoes 4. Some mechanism for outflow of air at the top of the vortex (I.e. divergence aloft) Structure: 1. Low-pressure center, with steep pressure gradient [seen in any vortex] [not as steep as tornado= 2. Cyclindrical wall cloud, with highest winds and rapidly rising air (condensation) winds are highest where radius is smallest 3. Descending cooler air in center, forming an “eye” (adiabatic warming) 4. Long “feeder” cloud bands spiraling into the low 5. Outflow at the top Hurricanes need a place to start – some pre-existing low-pressure area Stages in Hurricane Formation Formation: from a pre-existing “disturbance” (=low pressure center), often an easterly wave Strengthens IF…. - The low is strong enough - Outflow at the top develops - Remains over warm water Stages in development: 1. Tropical disturbance (easterly wave) – no closed isobars; winds << 60kph 2. Tropical depression – first closed isobar(s); winds still <= 60kph 3. Tropical storm – rotation distinct winds 60-120 kph 4. Hurricane – large vortex; winds >120kph Structure: Cylindrical wall cloud Eye – descending air in the middle; low-pressure center Spiral rain bands – feeding into center system; Outflow – at the top When: late summer into autumn (sea surface not warm enough earlier) Where: tropica;/subtropical oceans and seas (mT air), but outside 10N - 10S (coriolis), drift westward (trade winds) but also somewhat away from equator (coriolis) All hurricanes spiral counter-clockwise at the base! (or clockwise if you are south of equator) As air comes down, it warms adiabatically; ** p. 78 ** Cross-section of a hurricane: - Wall cloud - Outer rain bands - Eye Wind speed is highest in the eye wall at intermediate height - Eye wall = highest wind speeds Hurricane Katrina – rainfall heaviest to north Storm Surge * Hurrican Intensity Scale in book (Table 12-2); Saffir-Simpson Scale *wind speed matters most September – peak month for hurricanes Hurricanes are drawn towards South (deflected to the right) bc CORIOLIS Hurricane Gilbert Tornadoes vs. Hurricanes (p.75) Both require flat surface to get started Rotation is induced differently (tornado is from above, hurricane is below bc coriolis) Tornadoes require strong cold front – warm & cold air mass; hurricanes just need warm, wet air Both need and outflow mechanism above 10/14 *Know symbols and meanings on p. 80 of workbook ** Possible Controls of local (Athens) weather: Global: - ITC low pressure - Trade winds - Subtropical highs - Westerlies Regional: - Monsoonal high or low pressure Local: - Local air masses - Locally prevailing wind direction(s) - Local high or low pressure centers - Local fronts (as with mid-latitude cyclone) - Local convection Regional Controls: - Monsoon system (N. American in winter and Spring) - Jet Streams – steer storms below o Separates warmer and colder air masses - “Coupling Effect” o if air streams are coming together, higher pressure is enhanced because air is being pushed down Jet Streams and Air Masses Zonal flow -> typical, seasonal temperatures Undulating Flow -> warm air, father to the north, cold air farther south (usually in the east) Anatomy of a Mid-Latitude Cyclone With transects through the low (above) and the fronts (below) Tropical Cyclone Life Cycle – As it comes across US (starting as a new low off the Pacific Coast) Occlusion Sequence: generally happens while the system is crossing over the US Cyclone & Anti-Cyclone w/ Jet Stream: Surface low associated with divergence aloft, surface high associated with convergence aloft Storm Tracks: movement of the surface low: What to look for in a forecast: Current Conditions: 1) Temperature: general level of comfort, general dynamics of system, potential wetness, etc. a. Most processes go faster when they are warmer! 2) Wind Direction: will it likely get warmer or cooler? (If Winds are S it is warmer, if winds are South It is getting colder) a. Probably location of high or low b. Clue to know scenario; e.g. warm front or cold front 3) Dew-point Temperature: how wet or dry air actually is a. High temp = wet air b. Low temp= dry air 4) Actual Forecast: a. Temperature Range; day and night b. Sky conditions (and trend); clear/cloudy etc. c. Precipitation (and trend); Steps in Composing a Forecast: 1. Locate relevant HIGHS and LOWS on a map; (this will be given usually) a. Also know the directions that they are going! 2. Estimate the track of the highs and lows, locating where each would be on each day of a 2-4 day forecast period 3. To compose forecast location (e.g. Athens) – what kind of sky conditions are implied by the locations of the highs and lows AND by how that high and low is moving? How might this change over the forecast period? 4. What wind direction is implied by the locations of the highs and lows? How might this changeover the forecast period? 5. What if any precipitation seems likely, based on above information? In particular, are fronts involved and what spatial and temporal patterns of precipitation would be associated with each front? How does this change over the forecast period? 6. Finally, temperature levels over the forecast period will probably be based mainly on sky conditions and on the air masses involved. How would temperature levels change over the forecast period? (i.e. Describe temperature trends over the period.) Practicum: Starting Points: What: - Wind direction around a high (clockwise!) - Around a low (counter-clockwise) - What kind of clouds are around warm front? o Around cold front? Common Weather Scenarios in GA & in the SE p.83-91 in workbook Buy-Ballot’s Law: if you stand with your back to the wind, low pressure will be to your left (N. Hemisphere!) Homework answers: North Wind – high to NW – coldest nights of the winter (until high moves); could also get N wind after a winter cyclone with cold front NE Wind – high or low off coast, maybe a low approaching from the west; - A high and a low in the right position off the coast could each cause NE wind for us - A low appreoaching from the west could also draw wind from the E or NE - Result: cold-air damning by the mountains NW Wind – usually behind a cold front, with influx of cold air: windy, clear and drier for 2-3 days S/SW Wind – we’d be in warm sector but cold front coming SE Wind – more huid, greater chance of pop-up thunderstorms, especially in summer (but not only)
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'