A surface weather analysis for the United States on October 21, 2006.

A surface weather analysis is a special type of weather map which provides a view of weather elements over a geographical area at a specified time based on information from ground based weather stations.^[1] Weather maps are created by plotting or tracing the values of relevant quantities such as sea level pressure, temperature, cloud cover onto a geographical map to help find synoptic scale features such as weather fronts. Image File history File links Surface_analysis. ... Image File history File links Surface_analysis. ... These symbols, showing various weather fronts, might be found on a weather map. ... Weather is a term that encompasses phenomena in the atmosphere of a planet. ... Atmospheric pressure is the pressure caused by the weight of air above any area in the Earths atmosphere. ... Fig. ... Cloud cover is the amount of the sky obscured by clouds when observed at a particular location. ... Cartography or mapmaking (in Greek chartis = map and graphein = write) is the study and practice of making maps or globes. ... It has been suggested that this article or section be merged into Synoptic scale meteorology. ... A guide to the symbols for weather fronts that may be found on a weather map. ...

The first weather maps in the 19th century were drawn well after the fact to help devise a theory on storm systems.^[2] After the advent of the telegraph, simultaneous observations of weather became possible for the first time, and beginning in the late 1840s, the Smithsonian Institution became the first organization to draw real-time surface analyses. Use of surface analyses began first in the United States, spreading worldwide during the 1870s. Use of the Norwegian cyclone model for frontal analysis began in the late 1910s across Europe, with its use finally spreading to the United States during World War II. The Smithsonian Institution Building or Castle on the National Mall serves as the Institutions headquarters. ... // The 1910s represent the culmination of European militarism which had its beginnings during the second half of the 19th Century. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000...

Surface weather analyses have special symbols which show frontal systems, cloud cover, precipitation, or other important information. For example, an H may represent high pressure, implying good and fair weather. An L on the other hand may represent low pressure, which frequently accompanies precipitation. Various symbols are used not just for frontal zones and other surface boundaries on weather maps, but also to depict the present weather at various locations on the weather map. Areas of precipitation help determine the frontal type and location. A high, high-pressure cell, or high pressure area is a region where the atmospheric pressure is greater than the surrounding area. ... A large low-pressure system swirls off the southwestern coast of Iceland, illustrating the maxim that nature abhors a vacuum. ...

History of surface analysis

See also: History of surface weather analysis

Surface analysis of Great Blizzard of 1888 on March 12, 1888 at 10 pm

The use of weather charts in a modern sense began in the middle portion of the 19th century in order to devise a theory on storm systems.^[3] The development of a telegraph network by 1845 made it possible to gather weather information from multiple distant locations quickly enough to preserve its value for real-time applications. The Smithsonian Institution developed its network of observers over much of the central and eastern United States between the 1840s and 1860s once Joseph Henry took the helm.^[4] The U.S. Army Signal Corps inherited this network between 1870 and 1874 by an act of Congress, and expanded it to the west coast soon afterwards. The history of surface weather analysis concerns the timetable of developments related to surface weather analysis. ... Image File history File links Size of this preview: 433 × 600 pixelsFull resolution (915 × 1267 pixel, file size: 723 KB, MIME type: image/gif) Image of Great Blizzard of 1888 from the NOAA library http://docs. ... Image File history File links Size of this preview: 433 × 600 pixelsFull resolution (915 × 1267 pixel, file size: 723 KB, MIME type: image/gif) Image of Great Blizzard of 1888 from the NOAA library http://docs. ... This article or section does not adequately cite its references or sources. ... Telegraphy (from the Greek words tele = far away and grapho = write) is the long distance transmission of written messages without physical transport of letters, originally over wire. ... The U.S. Army Signal Corps was founded in 1861 by United States Army Major Albert J. Myer, a physician by training. ...

At first, all the data on the map was not taken at exactly the same time in the early days of these analyses because of a lack of time standardization. The first attempts at time standardization took hold in the Great Britain by 1855. The entire United States did not finally come under the influence of time zones until 1905, when Detroit finally established standard time.^[5] Internationally, other countries followed the lead of the United States in taking simultaneous weather observations, starting in 1873.^[6] Other countries then began preparing surface analyses. The use of frontal zones on weather maps did not appear until the introduction of the Norwegian cyclone model in the late 1910s, despite Loomis' earlier attempt at a similar notion in 1841.^[7] Since the leading edge of air mass changes bore resemblance to the military fronts of World War I, the term "front" came into use to represent these lines.^[8] Motto: Speramus Meliora; Resurget Cineribus (We Hope For Better Things; It Shall Rise From the Ashes - this motto was adopted after the disastrous 1805 fire that devastated the city) Nickname: The Motor City and Motown Location in Wayne County, Michigan Founded Incorporated July 24, 1701 1815  County Wayne County Mayor... Norwegian cyclone and Shapiro-Keyser model differences in frontal structure There are two models of cyclone development and lifecycles in common use - the Norwegian model and the Shapiro-Keyser Model. ... A military front is an area in which an army or nation expects to do most of its fighting. ... “The Great War ” redirects here. ...

Present weather symbols used on weather maps

Despite the introduction of the Norwegian cyclone model just after World War I, the United States did not formally analyze fronts on surface analyses until late 1942, when the WBAN Analysis Center opened in downtown Washington, D.C..^[9] The effort to automate map plotting began in the United States in 1969,^[10] with the process complete in the 1970s. Hong Kong completed their process of automated surface plotting by 1987.^[11] By 1999, computer systems and software had finally become sophisticated enough to allow for the ability to underlay on the same workstation satellite imagery, radar imagery, and model-derived fields such as atmospheric thickness and frontogenesis in combination with surface observations to make for the best possible surface analysis. In the United States, this development was achieved when Intergraph workstations were replaced by n-AWIPS workstations.^[12] By 2001, the various surface analyses done within the National Weather Service were combined into the Unified Surface Analysis, which is issued every six hours and combines the analyses of four different centers.^[13] Recent advances in both the fields of meteorology and geographic information systems have made it possible to devise finely tailored products that take us from the traditional weather map into an entirely new realm. Weather information can quickly be matched to relevant geographical detail. For instance, icing conditions can be mapped onto the road network. This will likely continue to lead to changes in the way surface analyses are created and displayed over the next several years.^[14] Image File history File links Weather_symbolsNEW2. ... Image File history File links Weather_symbolsNEW2. ... Radar image of a tropical cyclone in the northern hemisphere. ... Nickname: Motto: Justitia Omnibus (Justice for All) Location of Washington, D.C., in relation to the states Maryland and Virginia Coordinates: Country United States Federal District District of Columbia Government  - Mayor Adrian M. Fenty (D)  - City Council Chairperson: Vincent C. Gray (D) Ward 1: Jim Graham (D) Ward 2: Jack... Categories: Stub | National Weather Service ... Satellite image of Hurricane Hugo with a polar low visible at the top of the image. ... A geographic information system (GIS) is a system for capturing, storing, analyzing and managing data and associated attributes which are spatially referenced to the earth. ...

Station model plotted on surface weather analyses

Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

Station model used on weather maps

See also: Station model

When analyzing a weather map, a station model is plotted at each point of observation. Within the station model, the temperature, dewpoint, wind, sea level pressure, pressure tendency, and ongoing weather are plotted.^[15] The circle in the middle represents cloud cover. If completely filled in, it is overcast. If conditions are completely clear, the circle is empty. If conditions are partly cloudy, the circle is partially filled in.^[16] Outside the United States, temperature and dewpoint are plotted in degrees Celsius. Each full flag on the wind barb represents 10 knots of wind, each half flag represents 5 knots. When winds reach 50 knots, a filled in triangle is used for each 50 knots of wind.^[17] In the United States, rainfall plotted in the corner of the station model are in imperial units, such as inches. Internationally, the standard rainfall measurment unit is the millimeter. Once a map has a field of station models plotted, the analyzing isobars (lines of equal pressure), isallobars (lines of equal pressure change), isotherms (lines of equal temperature), and isotachs (lines of equal wind speed) can be easily accomplished.^[18] The abstract present weather symbols used on surface weather analyses for obstructions to visibility, precipitation, and thunderstorms were devised to take up the least room possible on weather maps. Station model plotted on surface weather analyses When analyzing a weather map, a station model is plotted at each point of observation. ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ... A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ... The word isobar derives from the two ancient Greek words, ισος (isos), meaning equal, and βαρος (baros), meaning weight. In meteorology, an isobar is a line of equal or constant pressure on a graph, plot, or map; an isopleth of pressure. ... The word isobar derives from the two ancient Greek words, ισος (isos), meaning equal, and βαρος (baros), meaning weight. In meteorology, an isobar is a contour line of equal or constant pressure on a graph, plot, or map. ... An isotach is a line of equal or constant wind speed on a graph, plot, or map; an isopleth of wind speed. ...

Synoptic scale features

See also: Synoptic scale

A synoptic scale feature is one whose dimensions are large in scale, more than several hundred kilometers in length.^[19] Migratory pressure systems and frontal zones exist on this scale. It has been suggested that this article or section be merged into Synoptic scale meteorology. ...

Wind barb interpretation

Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...

Pressure centers

Centers of surface high and low pressure areas are found within closed isobars on a surface weather analysis where there the absolute maxima and minima in the pressure field, and can tell a user in a glance what the general weather is in their vicinity. Weather maps in English-speaking countries will depict their highs as Hs and lows as Ls,^[20] while Spanish-speaking countries will depict their highs as As and lows as Bs.^[21]

Low pressure

Low pressure systems, also known as cyclones, are located in minima in the pressure field. Rotation is inward and counterclockwise in the northern hemisphere as opposed to inward and clockwise in the southern hemisphere due to the coriolis force. Weather is normally unsettled in the vicinity of a cyclone, with increased cloudiness, increased winds, increased temperatures, and upward motion in the atmosphere which leads to an increased chance of precipitation. Polar lows can form over relatively mild ocean waters when cold air sweeps in from the ice cap, leading to upward motion and convection, usually in the form of snow. Tropical cyclones and winter storms are intense varieties of low pressure. Over land, thermal lows are indicative of hot weather during the summer. ^[22] Radar image of a tropical cyclone in the northern hemisphere. ... The Northern Hemisphere is the half of a planets surface (or celestial sphere) that is north of the equator (the word hemisphere literally means half ball). On the Earth, the Northern Hemisphere contains most of the land and about 88-90% of the human population. ... southern hemisphere highlighted in yellow (Antarctica not depicted). ... In physics, the Coriolis effect is an inertial force first described by Gaspard-Gustave Coriolis, a French scientist, in 1835. ...

High pressure

High pressure systems, also known as anticyclones, rotate outward and clockwise in the northern hemisphere as opposed to outward and counterclockwise in the southern hemisphere. Under surface highs, sinking motion leads to skies that are clearer, winds that are lighter, and there is a reduced chance of precipitation.^[23] There is normally a greater range between high and low temperature due to the drier air mass present. If high pressure persists, air pollution will build up due to pollutants trapped near the surface caused by the subsiding motion associated with the high.^[24] In meteorology, an anticyclone (that is, opposite to a cyclone) is a weather phenomenon in which there is a descending movement of the air and a high pressure area over the part of the planets surface affected by it. ...

Fronts

Main article: Weather fronts

Occluded cyclone example. The triple point is the intersection of the cold, warm, and occluded fronts.

Fronts in meteorology are the leading edges of air masses with different density (e.g., air temperature and/or humidity). When a front passes over an area, it is marked by changes in temperature, moisture, wind speed and direction, atmospheric pressure, and often a change in the precipitation pattern. Cold fronts are often closely associated with low pressure systems, normally lying at the leading edge of high pressure systems and, in the case of the polar front, at approximately the equatorward edge of the high-level polar jet. Fronts are generally guided by winds aloft, but they normally move at lesser speeds. In the northern hemisphere, they usually travel from some west to east direction (even though they can move in a more north-south direction as well). Movement is largely due to the pressure gradient force (due to horizontal differences in atmospheric pressure) and the Coriolis effect, caused by the earth spinning about its axis. Frontal zones can be contorted by geographic features like mountains and large bodies of water.^[13] A guide to the symbols for weather fronts that may be found on a weather map. ... Image File history File links Occludedcyclone. ... Image File history File links Occludedcyclone. ... In meteorology, an air mass is a large volume of air having fairly uniform characteristics of temperature, atmospheric pressure, and water vapor content. ... This article or section is not written in the formal tone expected of an encyclopedia article. ... This article or section does not cite any references or sources. ... In meteorology, a weather front is a boundary between two air masses with differing characteristics (e. ... The pressure gradient force is the force that is usually responsible for accelerating a parcel of air from a high atmospheric pressure region to a low pressure region, resulting in wind. ... In the inertial frame of reference (upper part of the picture), the black object moves in a straight line. ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ...

Cold front

A guide to the symbols for weather fronts that may be found on a weather map:
1. cold front
2. warm front
3. stationary front
4. occluded front
5. surface trough
6. squall line
7. dry line
8. tropical wave

A cold front's location is at the leading edge of the temperature drop off, which in an isotherm analysis would show up as the leading edge of the isotherm gradient, and it normally lies within a sharp surface trough. Cold fronts can move up to twice as fast and produce sharper changes in weather than warm fronts, since cold air is denser than warm air it rapidly replaces the warm air preceding the boundary. Cold fronts are typically accompanied by a narrow band of showers and thunderstorms. On weather maps, the surface position of the cold front is marked with the symbol of a blue line of triangles/spikes (pips) pointing in the direction of travel, and it is placed at the leading edge of the cooler air mass.^[13] Image File history File links NWS_weather_fronts. ... Image File history File links NWS_weather_fronts. ... In meteorology, a weather front is a boundary between two air masses with differing characteristics (e. ... An isotherm is a line of equal or constant temperature on a graph, plot, or map; an isopleth of temperature. ... A trough is an elongated region of relatively low atmospheric pressure, often associated with fronts. ...

Warm front

Warm fronts are at the leading edge of the temperature drop off, which is located on the equator-ward edge of the gradient in isotherms, and lie within broader troughs of low pressure than cold fronts. Warm fronts move more slowly than the cold front which usually follows due to the fact that cold air is more dense, and harder to remove from the earth's surface. This also forces temperature differences across warm fronts to be broader in scale. Clouds ahead of the warm front are mostly stratiform and rainfall gradually increases as the front approaches. Fog can also occur preceding a warm frontal passage. Clearing and warming is usually rapid after frontal passage. If the warm air mass is unstable, thunderstorms may be embedded among the stratiform clouds ahead of the front, and after frontal passage, thundershowers may continue. On weather maps, the surface location of a warm front is marked with a red line of half circles pointing in the direction of travel.^[13] This article or section does not cite any references or sources. ... Stratus Opacus Uniformis This article is about the meteorological phenomenon. ... Evening fog obscures Londons Tower Bridge from passers by. ...

Occluded front

An occluded front is formed during the process of cyclogenesis when a cold front overtakes a warm front.^[25] The cold and warm fronts curve naturally poleward into the point of occlusion, which is also known as the triple point in meteorology.^[26] It lies within a sharp trough, but the air mass behind the boundary can be either warm or cold. In a cold occlusion, the air mass overtaking the warm front is cooler than the cool air ahead of the warm front, and plows under both air masses. In a warm occlusion, the air mass overtaking the warm front is not as cool as the cold air ahead of the warm front, and rides over the colder air mass while lifting the warm air. A wide variety of weather can be found along an occluded front, with thunderstorms possible, but usually their passage is associated with a drying of the air mass. Occluded fronts are indicated on a weather map by a purple line with alternating half-circles and triangles pointing in direction of travel.^[13] Occluded fronts usually form around mature low pressure areas. In meteorology, a weather front is a boundary between two air masses with differing characteristics (e. ... Cyclogenesis is the development or strengthening of cyclonic circulation in the atmosphere. ... Satellite image of Hurricane Hugo with a polar low visible at the top of the image. ...

Stationary fronts and shearlines

A stationary front is a non-moving boundary between two different air masses, neither of which is strong enough to replace the other. They tend to remain essentially in the same area for extended periods of time, usually moving in waves.^[27] There is normally a broad temperature gradient behind the boundary with more widely spaced isotherm packing. A wide variety of weather can be found along a stationary front, but usually clouds and prolonged precipitation are found there. Stationary fronts will either dissipate after several days or devolve into shear lines, but can change into a cold or warm front if conditions aloft change. Stationary fronts are marked on weather maps with alternating red half-circles and blue spikes pointing in opposite directions, indicating no significant movement. In meteorology, a weather front is a boundary between two air masses with differing characteristics (e. ...

When stationary fronts become smaller in scale, degenerating to a narrow zone where wind direction changes significantly over a relatively short distance, they become known as shear lines.^[28] If the shear line becomes active with thunderstorms, it may support formation of a tropical storm or a regeneration of the feature back into a stationary front. A shear line is depicted as a line of red dots and dashes.^[13] This article is about weather phenomena. ...

Mesoscale features

See also: Mesoscale Convective System

Mesoscale features are smaller than synoptic scale systems like fronts, but larger than storm-scale systems like thunderstorms. Horizontal dimensions generally range from around 50 miles to several hundred miles.^[29] A Mesoscale Convective Systen (MCS) is a complex of thunderstorms which becomes organized on a scale larger than the individual thunderstorms, and normally persists for several hours or more. ... Mesoscale Meteorology refers to weather systems smaller than synoptic scale systems but larger than storm-scale cumulus systems. ... It has been suggested that this article or section be merged into Synoptic scale meteorology. ... The term storm-scale refers to weather systems with sizes on the order of individual thunderstorms. ... A mile is a unit of length, usually used to measure distance, in a number of different systems, including Imperial units, United States customary units and Norwegian/Swedish mil. ...

Dry line

The dry line is the boundary between dry and moist air masses east of mountain ranges with similar orientation to the Rockies, depicted at the leading edge of the dew point, or moisture, gradient. Near the surface, warm moist air is more dense than dry air of greater temperature, and thus the warm moist air wedges under the drier air like a cold front.^[30] At higher altitudes, the warm moist air is less dense than the cooler, drier air and the boundary slope reverses. In the vicinity of the reversal aloft, severe weather is possible, especially when a triple point is formed with a cold front. A dry line, dew point line, or Marfa front[1] is a boundary separating moist and dry air masses, and an important factor in severe weather frequency in the Great Plains of North America. ... Rocky Mountain National Park (photo courtesy of NPS) View of Colorado Rockies. ... Dew on a spider web The dew point or dewpoint of a given parcel of air is the temperature to which the parcel must be cooled, at constant barometric pressure, for the water vapor component to condense into water, called dew. ...

During daylight hours, drier air from aloft mixes down to the surface, causing an apparent movement of the dryline eastward. At night, the boundary reverts back to the west as there is no longer any sunshine to help mix the lower atmosphere.^[31] If enough moisture converges upon the dryline, it can be the focus of afternoon and evening thunderstorms.^[32] A dry line is depicted on United States surface analyses as a brown line with scallops, or bumps, facing into the moist sector. Dry lines are one of the few surface fronts where the special shapes along the drawn boundary do not necessarily reflect the boundary's direction of motion.^[33]

Outflow boundaries and squall lines

A shelf cloud such as this one can be a sign that a squall is imminent

Organized areas of thunderstorm activity not only reinforce pre-existing frontal zones, but they can outrun cold fronts. This outrunning occurs in a pattern where the upper level jet splits into two streams. The resultant mesoscale convective system (MCS) forms at the point of the upper level split in the wind pattern in the area of best low level inflow. The convection then moves east and equatorward into the warm sector, parallel to low-level thickness lines. When the convection is strong and linear or curved, the MCS is called a squall line, with the feature placed at the leading edge of the significant wind shift and pressure rise.^[34] Even weaker and less organized areas of thunderstorms will lead to locally cooler air and higher pressures, and outflow boundaries exist ahead of this type of activity, which can act as foci for additional thunderstorm activity later in the day.^[35] These features will commonly be depicted in the warm season across the United States on surface analyses, and they lie within surface troughs. If outflow boundaries or squall lines form over arid regions, a duststorm known as a haboob may result due to the high winds in their wake picking up dust from the desert floor.^[36] Squall lines are depicted on NWS surface analyses as an alternating pattern of two red dots and a dash labelled "SQLN" or "SQUALL LINE", while outflow boundaries are depicted as troughs with a label of "OUTFLOW BOUNDARY" or "OUTFLOW BNDRY". Image File history File links Shelfcloudspc. ... Image File history File links Shelfcloudspc. ... A Mesoscale Convective Systen (MCS) is a complex of thunderstorms which becomes organized on a scale larger than the individual thunderstorms, and normally persists for several hours or more. ... A haboob is a type of intense dust storm characteristic of very dry regions. ...

Idealized circulation pattern associated with a sea breeze

Image File history File links Download high-resolution version (1100x800, 30 KB) Author: Vaughan Weather Date: November 6th, 2006 Lake - Sea breeze chart. ... Image File history File links Download high-resolution version (1100x800, 30 KB) Author: Vaughan Weather Date: November 6th, 2006 Lake - Sea breeze chart. ...

Sea and land breeze fronts

Sea breeze fronts occur mainly on sunny days when the landmass warms up above the water temperature. Similar boundaries form downwind on lakes and rivers during the day, as well as offshore landmasses at night. Since the specific heat of water is so high, there is little diurnal change in bodies of water, even on the sunniest days. The water temperature varies less than 1^oC (1-2^o F). By contrast, the land, with a lower specific heat, can vary several degrees in a matter of hours.^[37] A: Sea breeze, B: Land breeze A sea-breeze (or seabreeze) is a wind from the sea that develops over land near coasts. ... The specific heat capacity (symbol c or s, also called specific heat) of a substance is defined as heat capacity per unit mass. ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... Fahrenheit is a temperature scale named after the German physicist Daniel Gabriel Fahrenheit (1686–1736), who proposed it in 1724. ...

During the afternoon, air pressure decreases over the land as temperature rises. The relatively cooler air over the sea rushes in to fill the gap. The result is a relatively cool onshore wind. This process usually reverses at night where the water temperature is higher relative to the landmass, leading to an offshore land breeze. However, if water temperatures are colder than the land at night, the sea breeze may continue, only somewhat abated. This is typically the case along the California coast, for example.

If enough moisture exists, thunderstorms can form along sea breeze fronts which then can send out outflow boundaries. This causes chaotic wind/pressure regimes if winds are light and variable with height. Like all other surface features, sea breeze fronts lie inside troughs of low pressure, but if surface data is not dense enough, this trough may not be readily apparent.^[37]

See also

• Cyclogenesis
• Extratropical cyclone
• History of surface weather analysis
• Synoptic scale
• Weather fronts
• Weather map

Cyclogenesis is the development or strengthening of cyclonic circulation in the atmosphere. ... A fictitious synoptic chart of an extratropical cyclone affecting the UK & Ireland. ... The history of surface weather analysis concerns the timetable of developments related to surface weather analysis. ... It has been suggested that this article or section be merged into Synoptic scale meteorology. ... A guide to the symbols for weather fronts that may be found on a weather map. ... These symbols, showing various weather fronts, might be found on a weather map. ...

References

2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... April 18 is the 108th day of the year in the Gregorian calendar (109th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... April 18 is the 108th day of the year in the Gregorian calendar (109th in leap years). ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... April 20 is the 110th day of the year in the Gregorian calendar (111th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 5 is the 125th day of the year in the Gregorian calendar (126th in leap years). ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... The Hydrometeorological Prediction Center is one of several Service Centers under the umbrella of the National Centers for Environmental Prediction (NCEP), operating under the control of the National Weather Service, which in turn is part of the National Oceanic and Atmospheric Administration (NOAA) of the U.S. government. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 5 is the 125th day of the year in the Gregorian calendar (126th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 5 is the 125th day of the year in the Gregorian calendar (126th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 5 is the 125th day of the year in the Gregorian calendar (126th in leap years). ... The Hydrometeorological Prediction Center is one of several Service Centers under the umbrella of the National Centers for Environmental Prediction (NCEP), operating under the control of the National Weather Service, which in turn is part of the National Oceanic and Atmospheric Administration (NOAA) of the U.S. government. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 5 is the 125th day of the year in the Gregorian calendar (126th in leap years). ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 5 is the 125th day of the year in the Gregorian calendar (126th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... April 29 is the 119th day of the year in the Gregorian calendar (120th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 10 is the 130th day of the year in the Gregorian calendar (131st in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 10 is the 130th day of the year in the Gregorian calendar (131st in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... April 29 is the 119th day of the year in the Gregorian calendar (120th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 10 is the 130th day of the year in the Gregorian calendar (131st in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 5 is the 125th day of the year in the Gregorian calendar (126th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 5 is the 125th day of the year in the Gregorian calendar (126th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 5 is the 125th day of the year in the Gregorian calendar (126th in leap years). ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 5 is the 125th day of the year in the Gregorian calendar (126th in leap years). ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... December 5 is the 339th day (340th in leap years) of the year in the Gregorian calendar. ... 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the CE era. ... May 10 is the 130th day of the year in the Gregorian calendar (131st in leap years). ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 22 is the 295th day of the year (296th in leap years) in the Gregorian Calendar, with 70 days remaining. ...

External links

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Atmospheric fronts

• "The Mid-Latitude Cyclone"
• Norwegian Cyclone Model -NWS
• Unified Surface Analysis Manual - NWS
• Unified Surface Analysis - NWS
• Glossary of Meteorology
• Cold Front Page