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The medium range forecast products include surface pressure patterns, circulation centers and fronts, daily maximum and minimum temperatures and anomalies, probability of precipitation in 12-hour increments, total 5-day precipitation accumulation for the next five days, and 500 hPa (mb) height forecasts for days 3–7. In addition, a narrative ...
Following lighter rain on 30 and 31 January, areas of Auckland flooded for a second time on the morning of 1 February after more heavy downpours. [10] MetService reported that about 20–30 millimetres per hour (0.79–1.18 inches per hour) of "intensive rainfall" had fallen in parts of Auckland in the early hours of 1 February. [29]
MetService is the National Meteorological Service of New Zealand, and is designated by the Minister of Transport to provide New Zealand's authorised meteorological warning service. [4] MetService issues Severe Weather Outlooks, Watches and Warnings under a Code of Practice that enables others to distribute this information in the national interest.
They use three levels of warning. The amber warning indicates that a rainfall intensity of 30 millimetres (1.2 in) per hour is expected. The red warning indicates rainfall amounts of 50 millimetres (2.0 in) per hour are anticipated. The black warning indicates that rainfall rates of 70 millimetres (2.8 in) are possible. [19]
Find the depth of rainfall from a storm of duration 6 hours and return period 10 years on a catchment of 5 km 2 in Sheffield. From the FSR maps, the M5-60 minutes rainfall is 20.5mm, and "r" = 0.4. Divide 20.5mm by 0.4 to get 51.3mm, which is the M5-2 days rainfall depth. Factor Z1 = 0.64, so multiply 51.3mm by 0.64 to get 32.8mm.
Most of the time, choosing first digits that would lead to a value nearest to 1000 works out best. [5] The plotting of this value within the station model allows for the analysis of isobars on weather maps. Within maps which plot data on constant pressure surfaces, the pressure is replaced with the height of the pressure surface. [16]
Data provided by MetService, Image enhancement by Metvuw. Mammatus Cloud Christmas Day 2005 Radiosondes (weather balloons) measuring upper air temperatures and winds are routinely launched from five stations around New Zealand.
Such maps have been in use since the mid-19th century and are used for research and weather forecasting purposes. Maps using isotherms show temperature gradients, [2] which can help locate weather fronts. Isotach maps, analyzing lines of equal wind speed, [3] on a constant pressure surface of 300 or 250 hPa show where the jet stream is located.