50:
1000:(MCS) forming at the point of the upper level split in the wind pattern running southeast 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. Even weaker and less organized areas of thunderstorms 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.
1085:, but do not move as quickly. Cold fronts and occluded fronts in the Northern Hemisphere usually travel from the northwest to southeast, while warm fronts move more poleward with time. In the Northern Hemisphere a warm front moves from southwest to northeast. In the Southern Hemisphere, the reverse is true; a cold or occluded front usually moves from southwest to northeast, and a warm front moves from northwest to southeast. Movement is largely caused by the pressure gradient force (horizontal differences in atmospheric pressure) and the
33:
1164:
603:
804:
1030:
339:, although any direction is possible. Occluded fronts are a hybrid merge of the two, and stationary fronts are stalled in their motion. Cold fronts and cold occlusions move faster than warm fronts and warm occlusions because the dense air behind them can lift as well as push the warmer air. Mountains and bodies of water can affect the movement and properties of fronts, other than atmospheric conditions. When the
816:
the boundary can be either warm or cold. In a cold occlusion, the air mass overtaking the warm front is cooler than the cold air mass receding from the warm front and plows under both air masses. In a warm occlusion, the cold air mass overtaking the warm front is warmer than the cold air mass receding from the warm front and rides over the colder air while lifting the warm air.
688:. Low pressure also creates surface winds deriving from high pressure zones and vice versa. 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. In addition, areas of precipitation help determine the frontal type and location.
1043:(showers, thundershowers, heavy rain and related unstable weather) is caused by air being lifted and condensing into clouds by the movement of the cold front or cold occlusion under a mass of warmer, moist air. If the temperature differences of the two air masses involved are large and the turbulence is extreme because of
988:
1073:
However, precipitation along warm fronts is relatively steady, as in light rain or drizzle. Fog, sometimes extensive and dense, often occurs in pre-warm-frontal areas. Although, not all fronts produce precipitation or even clouds because moisture must be present in the air mass which is being lifted.
1072:
is precipitation created through the lifting action of air due to air masses moving over terrain such as mountains and hills, which is most common behind cold fronts that move into mountainous areas. It may sometimes occur in advance of warm fronts moving northward to the east of mountainous terrain.
788:
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 still continue. On weather maps,
941:
will form downwind of north–south oriented mountain chains, leading to the formation of a lee trough. Near the surface during daylight hours, warm moist air is denser than dry air of greater temperature, and thus the warm moist air wedges under the drier air like a cold front. At higher altitudes,
819:
A wide variety of weather can be found along an occluded front, with thunderstorms possible, but usually their passage is also associated with a drying of the air mass. Within the occlusion of the front, a circulation of air brings warm air upward and sends drafts of cold air downward, or vice versa
815:
is formed when a cold front overtakes a warm front, and usually forms around mature low-pressure areas, including cyclones. The cold and warm fronts curve naturally poleward into the point of occlusion, which is also known as the triple point. It lies within a sharp trough, but the air mass behind
776:
Warm fronts are at the leading edge of a homogeneous advancing warm air mass, which is located on the equatorward edge of the gradient in isotherms, and lie within broader troughs of low pressure than cold fronts. A warm front moves more slowly than the cold front which usually follows because cold
910:
When stationary fronts become smaller in scale and stabilizes in temperature, degenerating to a narrow zone where wind direction changes significantly over a relatively short distance, they become known as shearlines. A shearline is depicted as a line of red dots and dashes. Stationary fronts may
894:
is a non-moving (or stalled) boundary between two 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, especially with parallel winds directions; They usually move in waves but not persistently. There is
740:
as well. Cold fronts can produce sharper and more intense changes in weather and move at a rate that is up to twice as fast as warm fronts, since cold air is more dense than warm air, lifting as well as pushing the warm air preceding the boundary. The lifting motion often creates a narrow line of
906:
A wide variety of weather can be found along a stationary front, but usually clouds and prolonged precipitation are found there. Stationary fronts either dissipate after several days or devolve into shear lines, but they can transform into a cold or warm front if the conditions aloft change.
533:
536:
Different air masses which affect North
America, as well as other continents, tend to be separated by frontal boundaries. In this illustration, the Arctic front separates Arctic from Polar air masses, while the Polar front separates Polar air from warm air masses.
736:. On weather maps, the surface position of the cold front is marked by a blue line with triangles pointing in the direction where cold air travels and it is placed at the leading edge of the cooler air mass. Cold fronts often bring rain, and sometimes heavy
651:
which provides a top view of weather elements over a geographical area at a specified time based on information from ground-based weather stations. Weather maps are created by detecting, plotting and tracing the values of relevant quantities such as
995:
Organized areas of thunderstorm activity not only reinforce pre-existing frontal zones, but can outrun actively existing cold fronts in a pattern where the upper level jet splits apart into two streams, with the resultant
1732:
369:
classification is the most widely accepted form of air mass classification. Air mass classifications are indicated by three letters: Fronts separate air masses of different types or origins, and are located along
753:
is present as the lifted moist warm air condenses. The concept of colder, dense air "wedging" under the less dense warmer air is too simplistic, as the upward motion is really part of a maintenance process for
829:
Occluded fronts are indicated on a weather map by a purple line with alternating half-circles and triangles pointing in direction of travel. The trowal is indicated by a series of blue and red junction lines.
973:(NWS) surface analyses as an orange line with scallops facing into the moist sector. Dry lines are one of the few surface fronts where the pips indicated do not necessarily reflect the direction of motion.
1003:
These features are often depicted in the warm season across the United States on surface analyses and lie within surface troughs. If outflow boundaries or squall lines form over arid regions, a
946:
is possible, especially when an occlusion or triple point is formed with a cold front. A weaker form of the dry line seen more commonly is the lee trough, which displays weaker differences in
343:
has diminished between the air masses, for instance after flowing out over a uniformly warm ocean, the front can degenerate into a mere line which separates regions of differing
724:
A cold front is located along and on the bounds of the warm side of a tightly packed temperature gradient. On surface analysis charts, this temperature gradient is visible in
1524:
907:
Stationary fronts are marked on weather maps with alternating red half-circles and blue spikes pointing opposite to each other, indicating no significant movement.
1809:
1609:
1839:
702:" describes boundaries which show instability, meaning air rises rapidly along and over the boundary to cause significant weather changes and heavy
1193:
249:
1666:
969:
are a particularly favored location. The dry line normally moves eastward during the day and westward at night. A dry line is depicted on
780:
This also forces temperature differences across warm fronts to be broader in scale. Clouds appearing ahead of the warm front are mostly
826:, the projection on the Earth's surface of the tongue of warm air aloft formed during the occlusion process of the depression or storm.
1993:
1007:
may result. Squall lines are depicted on NWS surface analyses as an alternating pattern of two red dots and a dash labelled SQLN or
789:
the surface location of a warm front is marked with a red line of semicircles pointing in the direction the air mass is travelling.
942:
the warm moist air is less dense than the cooler dry air and the boundary slope reverses. In the vicinity of the reversal aloft,
1093:'s spinning about its axis. Frontal zones can be slowed by geographic features like mountains and large bodies of warm water.
1910:
1640:
1532:
1417:
1336:
1252:
672:
features such as weather fronts. Surface weather analyses have special symbols which show frontal systems, cloud cover,
1725:
242:
213:
1300:
1988:
1881:
1528:
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49:
1066:, lee troughs, breezes, outflow boundaries and occlusions can lead to convection if enough moisture is available.
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1613:
820:
depending on the type of occlusion the front is experiencing. Precipitations and clouds are associated with the
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155:
81:
17:
698:
There are two different meanings used within meteorology to describe weather around a frontal zone. The term "
1817:
1617:
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69:
900:
1847:
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1197:
997:
313:
286:. Disturbed and unstable weather due to these differences often arises along the boundary. For instance,
36:
Approaching weather fronts are often visible from the ground, but are not always as well defined as this.
1945:
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1961:
1998:
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950:. When moisture pools along the boundary during the warm season, it can be the focus of diurnal
725:
208:
165:
710:" is weaker, bringing smaller changes in temperature and moisture, as well as limited rainfall.
1969:
1953:
1937:
1704:
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1039:
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on the other hand may represent low pressure, which frequently accompanies precipitation and
328:. Some fronts produce no precipitation and little cloudiness, although there is invariably a
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8:
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Office of the
Federal Coordinator for Meteorological Services and Supporting Research
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Air
Apparent: How meteorologists learned to map, predict, and dramatize weather
1357:
Air
Apparent: How meteorologists learned to map, predict, and dramatize weather
1169:
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1982:
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344:
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699:
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The third letter designates the stability of the atmosphere; it is labeled:
1762:
1328:
Meteorology Today: An introduction to weather, climate, and the environment
1123:
951:
873:
746:
737:
366:
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uperior air (dry air formed by significant upward lift in the atmosphere).
1133:
1082:
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The dry line may occur anywhere on earth in regions intermediate between
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may represent a high pressure area, implying fair or clear weather. An
335:
Cold fronts generally move from west to east, whereas warm fronts move
306:
287:
991:
A shelf cloud such as this one can be a sign that a squall is imminent
987:
1791:
602:
455:
1029:
1011:, while outflow boundaries are depicted as troughs with a label of
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784:, and rainfall more gradually increases as the front approaches.
468:
422:
143:
101:
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1004:
958:
448:
937:
increase on the north side of surface highs, areas of lowered
1090:
685:
1968:. Department of Atmospheric Sciences. Urbana-Champaign, IL:
1952:. Department of Atmospheric Sciences. Urbana-Champaign, IL:
1936:. Department of Atmospheric Sciences. Urbana-Champaign, IL:
929:, which is the boundary between air masses with significant
27:
Boundary separating two masses of air of different densities
1906:
1499:
1441:
1248:
777:
air is denser and harder to lift from the Earth's surface.
275:
785:
317:
354:
1037:
Fronts are the principal cause of significant weather.
961:
areas and warm seas. The southern plains west of the
1159:
911:
bring light snow or rain for a long period of time.
876:, especially if lifted by the advancing cold front.
807:
Occluded front depiction for the
Northern Hemisphere
1187:
1185:
676:, or other important information. For example, an
270:for which several characteristics differ, such as
1324:
1235:
1233:
1231:
1229:
1227:
1225:
1223:
1221:
1219:
1191:
320:. In summer, subtler humidity gradients known as
1980:
1905:(Report) (vers. 1 ed.). Honolulu, HI:
1769:. A Comprehensive Glossary of Weather (Report).
1350:
1348:
1247:(Report) (vers. 1 ed.). Honolulu, HI:
1182:
647:A surface weather analysis is a special type of
1298:
925:A similar phenomenon to a weather front is the
1405:
1216:
933:differences instead of temperature. When the
860:, usually found on the equatorward side of an
1345:
758:balance on the rotating Earth in response to
732:since cold fronts often align with a surface
243:
1876:. Chicago, IL: University of Chicago Press.
1760:
1409:The Environment: Principles and applications
1359:. Chicago, IL: University of Chicago Press.
899:behind the boundary with more widely spaced
1962:"Fronts: The boundaries between air masses"
1897:
1239:
1196:. STEC 521 lecture notes. Durham, NH:
868:characteristics, this air is susceptive to
728:and can sometimes also be identified using
597:
351:. This is most common over the open ocean.
250:
236:
1964:. Glossary – Weather World 2010 Project.
1948:. Glossary – Weather World 2010 Project.
1932:. Glossary – Weather World 2010 Project.
1871:
1699:. Glossary – Weather World 2010 Project.
1583:. Glossary – Weather World 2010 Project.
1469:. Glossary – Weather World 2010 Project.
1354:
1018:
1638:
1028:
986:
802:
601:
531:
31:
1858:– via amsglossary.allenpress.com.
1828:– via amsglossary.allenpress.com.
1685:– via amsglossary.allenpress.com.
1628:– via amsglossary.allenpress.com.
1301:"Bergeron classification of air masses"
1288:– via amsglossary.allenpress.com.
14:
1981:
1703:. Department of Atmospheric Sciences.
1587:. Department of Atmospheric Sciences.
1473:. Department of Atmospheric Sciences.
1385:Weather Underground (wunderground.com)
1192:Miller, Samuel T. (10 November 2000).
1911:Hydrometeorological Prediction Center
1299:Saravanan, K.J., ed. (27 June 2008).
1253:Hydrometeorological Prediction Center
415:characteristic of its source region:
355:Bergeron classification of air masses
879:
24:
1865:
214:Glossary of tropical cyclone terms
25:
2010:
1891:
1529:World Meteorological Organisation
1412:. Psychology Press. p. 309.
1331:. Cengage Learning. p. 296.
792:
516:older”) than the ground below it.
1994:Synoptic meteorology and weather
1898:Roth, David (21 November 2013).
1240:Roth, David (21 November 2013).
1162:
692:
411:The second letter describes the
48:
1900:Unified Surface Analysis Manual
1844:American Meteorological Society
1832:
1814:American Meteorological Society
1802:
1796:American Meteorological Society
1784:
1771:American Meteorological Society
1754:
1718:
1697:"Dry line: A moisture boundary"
1689:
1671:American Meteorological Society
1659:
1632:
1614:American Meteorological Society
1602:
1573:
1547:
1517:
1488:
1459:
1242:Unified Surface Analysis Manual
1081:Fronts are generally guided by
526:armer than the ground below it.
396:ontinental air masses (dry) and
382:The first letter describes its
1426:
1399:
1373:
1318:
1292:
1270:
976:
833:
156:Climate variability and change
13:
1:
1176:
1047:and the presence of a strong
765:
713:
622:6. squall / shear line
7:
1872:Monmonier, Mark S. (1999).
1842:. Glossary of Meteorology.
1812:. Glossary of Meteorology.
1780:– via geographic.org.
1669:. Glossary of Meteorology.
1612:. Glossary of Meteorology.
1355:Monmonier, Mark S. (1999).
1198:University of New Hampshire
1096:
1076:
998:Mesoscale Convective System
914:
522: if the air mass is
508: if the air mass is
406:aritime air masses (moist).
10:
2015:
1531:/ Eumetcal. Archived from
1325:Ahrens, C. Donald (2007).
1194:"Clouds and precipitation"
1022:
980:
918:
883:
837:
796:
769:
717:
632:
358:
224:Glossary of climate change
1915:National Hurricane Center
1305:weatherfront.blogspot.com
1280:. Glossary of Meteorology
1257:National Hurricane Center
616:3. stationary front
266:is a boundary separating
219:Glossary of tornado terms
1989:Meteorological phenomena
1726:"Chapter 2: Definitions"
1559:SKYbrary Aviation Safety
1504:National Weather Service
1446:National Weather Service
1381:"Mixed surface analysis"
1278:"Airmass classification"
1144:Surface weather analysis
1069:Orographic precipitation
1040:Convective precipitation
1033:Convective precipitation
971:National Weather Service
691:
635:Surface weather analysis
598:Surface weather analysis
309:are usually preceded by
1763:"[letter]
1641:"Dryline cross section"
1406:Park, Chris C. (2001).
1139:Norwegian cyclone model
1114:Atmospheric circulation
620:5. surface trough
618:4. occluded front
581:ontinental tropic; and
209:Glossary of meteorology
1970:University of Illinois
1954:University of Illinois
1938:University of Illinois
1705:University of Illinois
1589:University of Illinois
1475:University of Illinois
1387:. Current weather maps
1034:
1019:Precipitation produced
992:
870:convective instability
808:
630:
626:8. tropical wave
594:
37:
1129:Extratropical cyclone
1089:, which is caused by
1032:
990:
862:extratropical cyclone
806:
605:
535:
77:Atmospheric chemistry
35:
1840:"Orographic lifting"
1677:on 19 September 2011
1527:. English glossary.
1149:Trough (meteorology)
897:temperature gradient
864:. With its warm and
65:Atmospheric dynamics
42:Atmospheric sciences
1109:Atmosphere of Earth
614:2. warm front
612:1. cold front
607:Weather map symbols
290:can bring bands of
60:Atmospheric physics
44:
1850:on 14 October 2006
1761:Branick, Michael.
1647:on 20 January 2008
1581:"Stationary front"
1555:"Stationary Front"
1204:on 11 January 2005
1104:Anticyclonic storm
1035:
993:
848:is a near-surface
809:
654:sea-level pressure
643:High-pressure area
631:
595:
301:or be preceded by
40:
38:
1419:978-0-415-21771-2
1338:978-0-495-01162-0
963:Mississippi River
895:normally a broad
639:Low-pressure area
624:7. dry line
402: used for
392: used for
386:properties, with
260:
259:
16:(Redirected from
2006:
1973:
1957:
1941:
1925:
1923:
1921:
1904:
1887:
1860:
1859:
1857:
1855:
1846:. Archived from
1836:
1830:
1829:
1827:
1825:
1816:. Archived from
1806:
1800:
1799:
1788:
1782:
1781:
1779:
1777:
1758:
1752:
1751:
1749:
1747:
1741:
1735:. Archived from
1730:
1722:
1716:
1715:
1713:
1711:
1693:
1687:
1686:
1684:
1682:
1673:. Archived from
1663:
1657:
1656:
1654:
1652:
1643:. Archived from
1636:
1630:
1629:
1627:
1625:
1620:on 14 March 2007
1616:. Archived from
1606:
1600:
1599:
1597:
1595:
1577:
1571:
1570:
1568:
1566:
1551:
1545:
1544:
1542:
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1535:on 31 March 2014
1521:
1515:
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1510:
1492:
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1481:
1467:"Occluded front"
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1274:
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1265:
1263:
1246:
1237:
1214:
1213:
1211:
1209:
1200:. Archived from
1189:
1172:
1167:
1166:
1013:outflow boundary
892:stationary front
886:Stationary front
880:Stationary front
872:and can sustain
694:
666:geographical map
592:
588:
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572:
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560:
556:
548:
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341:density contrast
252:
245:
238:
119:Tropical cyclone
52:
45:
39:
21:
2014:
2013:
2009:
2008:
2007:
2005:
2004:
2003:
1979:
1978:
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1866:Further reading
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1820:on 5 March 2007
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1099:
1087:Coriolis effect
1079:
1027:
1021:
985:
979:
923:
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888:
882:
852:in between the
842:
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633:Main articles:
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628:9. trough
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1999:Weather fronts
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1892:External links
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1798:. 8 June 2016.
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1639:Cai, Huaqing.
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1561:. 20 July 2021
1546:
1516:
1498:. Norman, OK:
1496:"Triple Point"
1487:
1458:
1425:
1418:
1398:
1372:
1365:
1344:
1337:
1317:
1291:
1269:
1215:
1180:
1178:
1175:
1174:
1173:
1170:Weather portal
1157:
1156:
1151:
1146:
1141:
1136:
1131:
1126:
1121:
1116:
1111:
1106:
1100:
1098:
1095:
1078:
1075:
1023:Main article:
1020:
1017:
981:Main article:
978:
975:
944:severe weather
919:Main article:
916:
913:
884:Main article:
881:
878:
838:Main article:
835:
832:
813:occluded front
799:Occluded front
797:Main article:
794:
793:Occluded front
791:
770:Main article:
767:
764:
718:Main article:
715:
712:
695:
690:
670:synoptic scale
611:
599:
596:
530:
529:
528:
527:
517:
500:
499:
498:
488:
475:
462:
442:
429:
409:
408:
407:
397:
359:Main article:
356:
353:
326:severe weather
258:
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255:
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247:
240:
232:
229:
228:
227:
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216:
211:
203:
202:
196:
195:
194:
193:
185:
184:
178:
177:
176:
175:
174:
173:
168:
161:Climate change
158:
153:
152:
151:
138:
137:
131:
130:
129:
128:
127:
126:
116:
115:
114:
109:
96:
95:
89:
88:
87:
86:
85:
84:
74:
73:
72:
62:
54:
53:
26:
18:Weather fronts
9:
6:
4:
3:
2:
2011:
2000:
1997:
1995:
1992:
1990:
1987:
1986:
1984:
1977:
1971:
1967:
1963:
1959:
1955:
1951:
1947:
1946:"Warm fronts"
1943:
1939:
1935:
1931:
1930:"Cold fronts"
1927:
1916:
1912:
1908:
1901:
1896:
1895:
1885:
1883:0-226-53422-7
1879:
1875:
1870:
1869:
1849:
1845:
1841:
1835:
1819:
1815:
1811:
1805:
1797:
1793:
1787:
1772:
1768:
1766:
1757:
1742:on 6 May 2009
1738:
1734:
1727:
1721:
1706:
1702:
1698:
1692:
1676:
1672:
1668:
1662:
1646:
1642:
1635:
1619:
1615:
1611:
1605:
1590:
1586:
1582:
1576:
1560:
1556:
1550:
1534:
1530:
1526:
1520:
1505:
1501:
1497:
1491:
1476:
1472:
1468:
1462:
1447:
1443:
1439:
1435:
1434:"Overrunning"
1429:
1421:
1415:
1411:
1410:
1402:
1386:
1382:
1376:
1368:
1366:0-226-53422-7
1362:
1358:
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1349:
1340:
1334:
1330:
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1234:
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1199:
1195:
1188:
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1074:
1071:
1070:
1065:
1060:
1058:
1054:
1050:
1046:
1042:
1041:
1031:
1026:
1025:Precipitation
1016:
1014:
1010:
1006:
1001:
999:
989:
984:
974:
972:
968:
967:United States
964:
960:
955:
953:
952:thunderstorms
949:
945:
940:
936:
932:
928:
922:
912:
908:
904:
902:
898:
893:
887:
877:
875:
874:thunderstorms
871:
867:
863:
859:
855:
851:
847:
841:
831:
827:
825:
824:
817:
814:
805:
800:
790:
787:
783:
778:
773:
763:
761:
760:frontogenesis
757:
752:
748:
747:thunderstorms
744:
739:
738:thunderstorms
735:
731:
727:
721:
711:
709:
705:
704:precipitation
701:
689:
687:
683:
679:
675:
674:precipitation
671:
668:to help find
667:
663:
659:
655:
650:
644:
640:
636:
608:
604:
584:
576:
564:
552:
540:
534:
521:
518:
507:
504:
503:
501:
492:
489:
486:
479:
476:
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466:
463:
460:
453:
446:
443:
440:
433:
430:
427:
420:
417:
416:
414:
410:
401:
398:
391:
388:
387:
385:
381:
380:
379:
377:
373:
368:
362:
352:
350:
346:
345:wind velocity
342:
338:
333:
331:
327:
323:
319:
315:
314:precipitation
312:
308:
304:
300:
299:precipitation
297:
293:
292:thunderstorms
289:
285:
281:
277:
273:
269:
265:
264:weather front
253:
248:
246:
241:
239:
234:
233:
231:
230:
225:
222:
220:
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215:
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210:
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198:
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179:
172:
169:
167:
164:
163:
162:
159:
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133:
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125:
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113:
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105:
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100:
99:
98:
97:
94:
91:
90:
83:
80:
79:
78:
75:
71:
68:
67:
66:
63:
61:
58:
57:
56:
55:
51:
47:
46:
43:
34:
30:
19:
1976:
1966:Online guide
1965:
1950:Online guide
1949:
1934:Online guide
1933:
1918:. Retrieved
1873:
1852:. Retrieved
1848:the original
1834:
1822:. Retrieved
1818:the original
1810:"Convection"
1804:
1794:. Glossary.
1786:
1774:. Retrieved
1764:
1756:
1744:. Retrieved
1737:the original
1720:
1708:. Retrieved
1701:Online guide
1700:
1691:
1679:. Retrieved
1675:the original
1667:"Lee trough"
1661:
1649:. Retrieved
1645:the original
1634:
1622:. Retrieved
1618:the original
1610:"Shear line"
1604:
1592:. Retrieved
1585:Online guide
1584:
1575:
1563:. Retrieved
1558:
1549:
1537:. Retrieved
1533:the original
1519:
1507:. Retrieved
1490:
1478:. Retrieved
1471:Online guide
1470:
1461:
1449:. Retrieved
1440:. Glossary.
1437:
1428:
1408:
1401:
1389:. Retrieved
1384:
1375:
1356:
1327:
1320:
1308:. Retrieved
1304:
1294:
1282:. Retrieved
1272:
1260:. Retrieved
1206:. Retrieved
1202:the original
1124:Cyclogenesis
1080:
1067:
1062:In the warm
1061:
1038:
1036:
1012:
1008:
1002:
994:
956:
924:
909:
905:
889:
843:
828:
821:
818:
810:
779:
775:
723:
697:
681:
677:
646:
606:
582:
574:
562:
550:
538:
519:
505:
493: for
490:
480: for
477:
467: for
464:
447: for
444:
434: for
431:
421: for
418:
399:
389:
364:
334:
324:can trigger
303:squall lines
296:cumulonimbus
263:
261:
199:
29:
1134:Hadley cell
1083:winds aloft
1059:may occur.
1053:roll clouds
983:Squall line
977:Squall line
846:warm sector
840:Warm sector
834:Warm sector
756:geostrophic
662:cloud cover
658:temperature
649:weather map
557:ontinental
545:ontinental
347:known as a
307:warm fronts
288:cold fronts
280:temperature
272:air density
135:Climatology
93:Meteorology
1983:Categories
1920:22 October
1854:22 October
1824:22 October
1776:22 October
1746:22 October
1710:22 October
1681:22 October
1651:5 December
1624:22 October
1594:22 October
1509:22 October
1480:22 October
1262:22 October
1177:References
1154:Warm front
1119:Cold front
1049:jet stream
1045:wind shear
1009:squal line
935:westerlies
858:cold front
854:warm front
782:stratiform
772:Warm front
766:Warm front
749:if enough
720:Cold front
714:Cold front
349:shear line
330:wind shift
311:stratiform
268:air masses
200:Glossaries
1539:28 August
1057:tornadoes
903:packing.
726:isotherms
708:katafront
485:quatorial
374:of lower
322:dry lines
1792:"Haboob"
1565:19 April
1525:"Trowal"
1391:19 April
1310:19 April
1097:See also
1077:Movement
948:moisture
939:pressure
931:moisture
927:dry line
921:Dry line
915:Dry line
901:isotherm
856:and the
850:air mass
751:humidity
700:anafront
589:aritime
569:aritime
512:older (“
459:ntarctic
384:moisture
376:pressure
367:Bergeron
361:Air mass
337:poleward
305:, while
284:humidity
191:Aeronomy
182:Aeronomy
166:category
149:category
124:category
107:category
82:category
70:category
965:in the
743:showers
730:isobars
664:onto a
593:ropic.)
549:rctic;
426:ropical
413:thermal
372:troughs
144:Climate
102:Weather
1880:
1416:
1363:
1335:
1284:22 May
1208:8 July
1064:season
1055:" and
1005:haboob
959:desert
823:trowal
734:trough
706:. A "
686:storms
660:, and
641:, and
573:olar;
561:olar;
472:onsoon
282:, and
171:portal
112:portal
1903:(PDF)
1740:(PDF)
1729:(PDF)
1451:2 May
1245:(PDF)
1091:Earth
866:humid
693:Types
487:, and
452:rctic
1922:2006
1907:NOAA
1878:ISBN
1856:2006
1826:2006
1778:2006
1748:2006
1712:2006
1683:2006
1653:2006
1626:2006
1596:2006
1567:2022
1541:2013
1511:2006
1500:NOAA
1482:2006
1453:2010
1442:NOAA
1414:ISBN
1393:2022
1361:ISBN
1333:ISBN
1312:2022
1286:2008
1264:2006
1249:NOAA
1210:2011
844:The
745:and
439:olar
365:The
316:and
294:and
276:wind
1765:'O'
1438:'O'
1436:.
1051:, "
811:An
786:Fog
585:is
577:is
565:is
553:is
541:is
454:or
318:fog
1985::
1913:/
1909:/
1731:.
1557:.
1502:/
1444:/
1383:.
1347:^
1303:.
1255:/
1251:/
1218:^
1184:^
1015:.
954:.
890:A
762:.
656:,
637:,
583:mT
575:cT
563:mP
551:cP
539:cA
378:.
332:.
278:,
274:,
262:A
1972:.
1956:.
1940:.
1924:.
1886:.
1767:"
1750:.
1714:.
1655:.
1598:.
1569:.
1543:.
1513:.
1484:.
1455:.
1422:.
1395:.
1369:.
1341:.
1314:.
1266:.
1212:.
682:L
678:H
609::
591:t
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579:c
571:p
567:m
559:p
555:c
547:a
543:c
537:(
524:w
520:w
514:k
510:c
506:k
495:s
491:S
483:e
478:E
474:,
470:m
465:M
461:,
457:A
450:A
445:A
441:,
437:p
432:P
428:,
424:t
419:T
404:m
400:m
394:c
390:c
251:e
244:t
237:v
20:)
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