413:, the upper level steering pattern and disturbances around the ridge are critical for influencing where thunderstorms develop on any given day. The exact strength and position of the subtropical ridge also governs how far north the tropical easterly winds aloft can spread. If the ridge is too close to a particular area, the sinking air at its center suppresses thunderstorms and can result in a significant monsoon "break." If the ridge is too far away or too weak, the east winds around the high are inadequate to bring tropical moisture into the mountains of Mexico and southwest U.S. However, if the ridge sets up in a few key locations, widespread and potentially severe thunderstorms can develop.
363:
386:
33:
129:
1089:
256:
406:(several km to 100 km, hours to one day temporally) and the extremely varied topography. The larger-scale atmospheric motions may control the distribution of water vapor and the general stability or instability (that is, the tendency to form storms) in the atmosphere; nevertheless, local topographic effects are critical to the geographic and even temporal distribution of convective activity.
900:
616:
564:
482:(NAM) is a "true monsoon" has been controversial. Until the late 1970s, there was serious debate about whether a monsoon truly existed in North America. However, according to NOAA, considerable research culminating in 1993 established the fact that that a summer monsoon develops over much of Mexico and the intermountain region of the U.S.
176:, which are frequently well below the freezing mark. In some years, this delayed effect is more substantial if the dryline which separates the hot and dry airmass to the Northwest from the humid monsoon airmass to the Southeast, fails to migrate. This can prevent tropical moisture from reaching farther Northwest towards
137:
485:
The controversy continues in part because of the incomplete reversal of the winds during the NAM. The prevailing winds shift from westerly before to southerly during the NAM. Because this is not a complete 180-degree reversal, some climatologists claim the weather pattern is not a true monsoon. Other
397:
Rainfall during the monsoon is not continuous. It varies considerably, depending on a variety of factors. There are usually distinct "burst" periods of heavy rain during the monsoon, and "break" periods with little or no rain. The variability is difficult to understand and predict, because it results
342:
for the daily development of thunderstorms. Thus much of the monsoon rainfall occurs in mountainous terrain. For example, monsoon rainfall in the Sierra Madre
Occidental typically ranges from 10 to 15 inches. Since the southwest U.S. is at the northern fringe of the monsoon, precipitation is less and
102:
are fueled by daytime heating and build up during the late afternoon and early evening. Typically, these storms dissipate by late night, and the next day starts out fair, with the cycle repeating daily. The cycle typically loses its energy by mid-September when much drier conditions are reestablished
183:
In early summer, the monsoon starts with a shift in wind patterns as Mexico and the southwest U.S. warm under intense solar heating. The prevailing winds start to flow from somewhat cooler moist ocean areas into hotter, dry land areas. Precipitation increases in late May to early June in southern
267:
Monsoon precipitation accounts for a substantial portion of annual precipitation in northwest Mexico and the
Southwestern United States. Most of these areas receive over half their annual precipitation from the monsoon. Many desert plants are adapted to take advantage of this brief wet season.
171:
In the monsoon area, the late spring period is very hot and dry, because the dry western side subtropical high pressure ridge and dry continental air have not begun to 'shift' northwards yet. During this period, inland areas have extremely low relative humidity, and characteristically very low
302:
can become raging rivers in an instant, even when no storms are visible as a storm can cause a flash flood tens of miles away. Lightning strikes are also a significant danger. Because it is dangerous to be caught in the open when these storms suddenly appear, many golf courses in
Arizona have
291:
threats by providing moisture at higher elevations during the wildfire season. Heavy monsoon rain can lead to excess winter plant growth, in turn a summer wildfire risk. A lack of monsoon rain can hamper summer seeding, reducing excess winter plant growth but worsening drought.
231:
can add additional moisture to the atmosphere which will then flow into
Arizona and New Mexico. Finally, if the southern Plains of the U.S. are unusually wet and green during the early summer months, that area can also serve as a moisture source.
343:
tends to be more variable. Areas farther west of the core monsoon region, namely
California and Baja California, typically receive only spotty monsoon-related rainfall. In those areas, the intense solar heating is not strong enough to overcome a
1052:
Although the North
American monsoon region experiences pronounced precipitation seasonally, it differs from a true monsoon, which is characterized by a distinct seasonal reversal of prevailing surface winds. No such situation occurs in
355:
of
Southern California, but rarely reaches the coastal strip. As shown in the panorama below, a wall of thunderstorms, only a half-hour's drive away, is a common sight from the sunny skies along the coast during the monsoon.
454:
None of these factors can perfectly predict the variability. These factors are related to each other and are not independent. For example, sea surface temperatures affect all the other factors to some extent.
235:
As precipitable water values rise in early summer, brief but often torrential thunderstorms can occur, especially over mountainous terrain. This activity is occasionally enhanced by the passage of
904:
620:
416:
Monsoon variability from one summer to the next is substantial, and exceeds the normal monsoon seasonal precipitation at most locations. For example, the normal monsoon precipitation at
156:) over northwestern Mexico and southwestern US resulting in summer thunderstorms, especially at higher elevations. The North American monsoon is not as strong or persistent as its
705:
409:
The monsoon ridge is almost as strong as the one which develops over Asia during the summer. However, since the lower level moisture flow is not as persistent as in the
423:
Research since 2010 has investigated the possible causes behind North
American monsoon variability. The following factors affect the North American monsoon:
362:
470:
further inland. The combination of these factors blocked moist tropical air from reaching the
American Southwest, leading to below average rainfall.
831:
462:
shifts less than in typical years. For instance in 2020, the subtropical high remained further south than usual due to the influence of a strong
369:
347:. Winds do turn toward the land in these areas, but the cool moist air actually stabilizes the atmosphere. The monsoon pushes as far west as the
420:
is 6.06 inches (154 mm). The driest monsoon season measured 1.59 inches (40 mm), and the wettest measured 13.84 inches (352 mm).
1093:
1129:
208:(a trough of low pressure from intense surface heating) develops over the Mexican Plateau and the Desert Southwest of the United States.
1038:
574:
730:
227:
by easterly winds aloft. Once the forests of the Sierra Madre
Occidental green up from the initial monsoon rains, evaporation and
832:
US Crop Reporting Board; Bureau of Agricultural Economics; Agricultural Marketing Service; Agricultural Statistics Board (2006).
625:
17:
782:
1032:
448:
220:
123:
568:
1071:
582:
168:
in Asia. However, the North American monsoon shares most of the basic characteristics of its Indian counterpart.
984:
959:
442:
308:
545:
520:
761:
960:"Diurnal variation of the lower tropospheric flow over the Arizona low desert from SWAMP-1993 observations"
1114:
219:. The Gulf of California, a narrow body of water surrounded by mountains, is particularly important for
180:
until later in the summer. If this pattern prevails, the Nevada deserts may receive almost no monsoon.
1109:
838:. Crop Reporting Board, Statistical Reporting Service, U.S. Department of Agriculture. pp. 30, 36.
399:
345:
continual supply of cold water from the North Pacific Ocean moving down the west coast of North America
68:
192:
in early July. It extends into the southwest United States as it matures in mid-July, when an area of
939:
Reyes, S; Douglas, MW; Maddox, RA (1994). "El Monzon del suroeste de Norteamérica (TRAVASON/SWAMP)".
789:
240:
67:
is a term for a pattern of pronounced increase in thunderstorms and rainfall over large areas of the
909:
1124:
918:
734:
631:
312:
1067:
1119:
833:
433:
427:
327:
79:
849:
463:
27:
Pattern of thunderstorms and rainfall in the southwestern United States and northwestern Mexico
1022:
393:, Utah. This type of monsoonal pattern is very common in the late summer of the southwest US.
403:
157:
586:
971:
665:
532:
373:
316:
738:
8:
999:
811:
458:
In some years, the Nevada deserts may receive almost no monsoon influence if the western
975:
706:"Drought continues to expand as the monsoon in the Southwest has been largely a no-show"
669:
536:
683:
344:
228:
212:
193:
145:
41:
211:
The thermal low sets up circulation that brings pulses of low level moisture from the
184:
Mexico and spreads along the western slopes of the Sierra Madre Occidental, reaching
144:
The North American monsoon is a complex weather process that brings moisture from the
1028:
635:
352:
348:
320:
281:
244:
197:
95:
687:
979:
673:
540:
459:
398:
from the complex interactions between atmospheric circulation features at both the
1068:"The Future of the North American Monsoon (Global Decadal Climate Predictability)"
417:
339:
335:
204:
region, creating wind flow aloft from the east or southeast. At the same time, a
165:
161:
149:
410:
390:
299:
269:
236:
224:
153:
1103:
385:
273:
216:
276:
are considered relatively "wet" when ranked among other deserts such as the
223:. Upper level moisture is also transported into the region, mainly from the
331:
201:
177:
99:
871:
32:
304:
295:
205:
140:
Typical precipitation pattern of the North American monsoon (green arrow)
119:
678:
653:
579:
Impact of Climate Change and Land Use in the Southwestern United States
467:
319:
and retention structures, similar to the flood control channels in the
315:
has prompted the city to develop an extensive system of concrete-lined
260:
185:
136:
173:
495:
288:
479:
402:(100 to 1000 km spatially, 1 day to 1 week, temporally) and
189:
128:
107:
87:
83:
37:
1088:
500:
277:
91:
72:
255:
326:
Once the monsoon is underway, mountain ranges, including the
651:
985:
10.1175/1520-0493(1996)124<1211:DVOTLT>2.0.CO;2
546:
10.1175/1520-0477(1997)078<2197:TNAM>2.0.CO;2
78:
Geographically, the weather pattern is centered over the
652:
Grantz, K; Rajagopalan, B; Clark, M; Zagona, E (2007).
98:, and typically occurs between June and mid-September.
575:"Review of Variability in the North American Monsoon"
221:
low-level moisture transport into Arizona and Sonora
783:"Reports to the Nation: The North American Monsoon"
938:
737:Forecast Office Flagstaff, Arizona. Archived from
1101:
699:
697:
654:"Seasonal Shifts in the North American Monsoon"
525:Bulletin of the American Meteorological Society
307:, flash flooding from storms funneled into the
1027:. Jones & Bartlett Learning. p. 187.
894:
892:
1066:Cook, Ben; Seager, Richard (September 2013).
872:"Arroyos - Albuquerque's Environmental Story"
694:
132:Weather pattern of the North American monsoon
106:Whether the North American monsoon is a true
200:, develops in the upper atmosphere over the
1021:Rohli, Robert V.; Vega, Anthony J. (2011).
889:
518:
1065:
466:over the northern Pacific, displacing the
1020:
983:
957:
677:
544:
259:A seasonal monsoon storm approaching the
812:"Tropical Cyclone Rainfall for the West"
703:
647:
645:
384:
298:is a serious danger during the monsoon.
254:
135:
127:
31:
389:An isolated thunderstorm rolls through
287:Monsoons often play a role in reducing
14:
1102:
610:
608:
606:
604:
602:
600:
598:
596:
558:
556:
1014:
850:"North American Monsoon Flash Floods"
642:
572:
519:Adams, David; Comrie, Andrew (1997).
372:Monsoonal thunderstorms as seen from
512:
1130:Weather events in the United States
1000:"North American Monsoon Highlights"
593:
553:
24:
1041:from the original on June 19, 2013
1002:. Albuquerque Weather Office, NOAA
759:
449:Gulf of California moisture surges
164:is not as high or as large as the
25:
1141:
1081:
704:Duginski, Paul (August 9, 2020).
303:thunderstorm warning systems. In
124:Gulf of California moisture surge
1087:
1072:Lamont-Doherty Earth Observatory
911:Monsoon Inter-annual Variability
903: This article incorporates
898:
809:
619: This article incorporates
614:
567: This article incorporates
562:
434:Large-scale circulation patterns
361:
1059:
992:
951:
932:
864:
842:
825:
583:United States Geological Survey
803:
775:
753:
723:
443:Intertropical Convergence Zone
380:
13:
1:
506:
473:
438:Previous year's precipitation
313:Sandia-Manzano mountain range
268:Because of the monsoons, the
1094:Monsoon in the United States
521:"The North American Monsoon"
113:
7:
958:Douglas, MW; Li, S (1996).
489:
478:Whether the North American
10:
1146:
250:
148:(and to lesser extent the
117:
69:southwestern United States
790:Climate Prediction Center
486:climatologists disagree.
82:in the Mexican states of
51:, variously known as the
919:National Weather Service
735:National Weather Service
632:National Weather Service
573:Adams, David K. (1997).
196:, called the monsoon or
1074:of Columbia University.
428:Sea surface temperature
328:Sierra Madre Occidental
110:remains controversial.
80:Sierra Madre Occidental
964:Monthly Weather Review
905:public domain material
762:"Maddox Type IV Event"
627:North American Monsoon
621:public domain material
569:public domain material
464:ridge of high pressure
394:
284:'s extreme diversity.
264:
141:
133:
49:North American monsoon
44:
18:North American Monsoon
388:
280:, and helps fuel the
258:
160:, mainly because the
139:
131:
35:
1096:at Wikimedia Commons
741:on February 28, 2008
374:El Cajon, California
976:1996MWRv..124.1211D
670:2007JCli...20.1923G
537:1997BAMS...78.2197A
447:Variability in the
243:of the remnants of
229:plant transpiration
61:New Mexican monsoon
1115:Gulf of California
760:Junker, Norman W.
679:10.1175/JCLI4091.1
658:Journal of Climate
395:
340:focusing mechanism
265:
213:Gulf of California
158:Indian counterpart
146:Gulf of California
142:
134:
45:
42:eastern New Mexico
1110:Climate of Mexico
1092:Media related to
710:Los Angeles Times
638:on June 12, 2008.
589:on July 18, 1997.
531:(10): 2197–2213.
353:Transverse Ranges
349:Peninsular Ranges
338:ranges provide a
321:Los Angeles River
309:Rio Grande Valley
282:Chihuahuan Desert
245:tropical cyclones
198:subtropical ridge
103:over the region.
71:and northwestern
53:Southwest monsoon
16:(Redirected from
1137:
1091:
1076:
1075:
1063:
1057:
1056:
1048:
1046:
1018:
1012:
1011:
1009:
1007:
996:
990:
989:
987:
970:(6): 1211–1224.
955:
949:
948:
936:
930:
929:
927:
925:
916:
902:
901:
896:
887:
886:
884:
882:
876:albuqhistsoc.org
868:
862:
861:
859:
857:
846:
840:
839:
829:
823:
822:
820:
818:
807:
801:
800:
798:
796:
787:
779:
773:
772:
770:
768:
757:
751:
750:
748:
746:
727:
721:
720:
718:
716:
701:
692:
691:
681:
664:(9): 1923–1935.
649:
640:
639:
634:. Archived from
618:
617:
612:
591:
590:
585:. Archived from
566:
565:
560:
551:
550:
548:
516:
460:subtropical high
441:Location of the
365:
21:
1145:
1144:
1140:
1139:
1138:
1136:
1135:
1134:
1125:Mexican Plateau
1100:
1099:
1084:
1079:
1064:
1060:
1044:
1042:
1035:
1019:
1015:
1005:
1003:
998:
997:
993:
956:
952:
937:
933:
923:
921:
914:
908:
899:
897:
890:
880:
878:
870:
869:
865:
855:
853:
848:
847:
843:
835:Crop Production
830:
826:
816:
814:
810:Roth, David M.
808:
804:
794:
792:
785:
781:
780:
776:
766:
764:
758:
754:
744:
742:
729:
728:
724:
714:
712:
702:
695:
650:
643:
624:
615:
613:
594:
563:
561:
554:
517:
513:
509:
492:
476:
418:Tucson, Arizona
383:
378:
377:
376:
371:
366:
336:Rio Grande Rift
263:on July 9, 2021
253:
166:Tibetan Plateau
162:Mexican Plateau
150:eastern Pacific
126:
116:
65:Arizona monsoon
57:Mexican monsoon
28:
23:
22:
15:
12:
11:
5:
1143:
1133:
1132:
1127:
1122:
1120:Madrean Region
1117:
1112:
1098:
1097:
1083:
1082:External links
1080:
1078:
1077:
1058:
1034:978-0763791018
1033:
1013:
991:
950:
931:
888:
863:
841:
824:
802:
774:
752:
722:
693:
641:
592:
552:
510:
508:
505:
504:
503:
498:
491:
488:
475:
472:
452:
451:
445:
439:
436:
431:
411:Indian monsoon
391:Wah Wah Valley
382:
379:
368:
367:
360:
359:
358:
296:Flash flooding
252:
249:
237:tropical waves
225:Gulf of Mexico
188:and southeast
154:Gulf of Mexico
115:
112:
26:
9:
6:
4:
3:
2:
1142:
1131:
1128:
1126:
1123:
1121:
1118:
1116:
1113:
1111:
1108:
1107:
1105:
1095:
1090:
1086:
1085:
1073:
1069:
1062:
1055:
1054:
1040:
1036:
1030:
1026:
1025:
1017:
1006:September 14,
1001:
995:
986:
981:
977:
973:
969:
965:
961:
954:
946:
942:
935:
924:September 14,
920:
913:
912:
906:
895:
893:
877:
873:
867:
851:
845:
837:
836:
828:
813:
806:
791:
784:
778:
763:
756:
740:
736:
732:
731:"The Monsoon"
726:
711:
707:
700:
698:
689:
685:
680:
675:
671:
667:
663:
659:
655:
648:
646:
637:
633:
629:
628:
622:
611:
609:
607:
605:
603:
601:
599:
597:
588:
584:
580:
576:
570:
559:
557:
547:
542:
538:
534:
530:
526:
522:
515:
511:
502:
499:
497:
494:
493:
487:
483:
481:
471:
469:
465:
461:
456:
450:
446:
444:
440:
437:
435:
432:
429:
426:
425:
424:
421:
419:
414:
412:
407:
405:
401:
392:
387:
375:
370:
364:
357:
354:
350:
346:
341:
337:
333:
329:
324:
322:
318:
314:
310:
306:
301:
297:
293:
290:
285:
283:
279:
275:
271:
262:
257:
248:
246:
242:
238:
233:
230:
226:
222:
218:
214:
209:
207:
203:
199:
195:
194:high pressure
191:
187:
181:
179:
175:
169:
167:
163:
159:
155:
151:
147:
138:
130:
125:
121:
111:
109:
104:
101:
100:Thunderstorms
97:
93:
89:
85:
81:
76:
74:
70:
66:
62:
58:
54:
50:
43:
39:
34:
30:
19:
1061:
1051:
1050:
1043:. Retrieved
1023:
1016:
1004:. Retrieved
994:
967:
963:
953:
944:
940:
934:
922:. Retrieved
910:
879:. Retrieved
875:
866:
854:. Retrieved
844:
834:
827:
817:February 29,
815:. Retrieved
805:
795:February 29,
793:. Retrieved
777:
767:February 29,
765:. Retrieved
755:
745:February 28,
743:. Retrieved
739:the original
725:
713:. Retrieved
709:
661:
657:
636:the original
626:
587:the original
578:
528:
524:
514:
484:
477:
457:
453:
422:
415:
408:
396:
332:Mogollon Rim
325:
294:
286:
266:
234:
215:and eastern
210:
202:Four Corners
182:
178:Death Valley
170:
143:
105:
77:
64:
60:
56:
52:
48:
46:
29:
1024:Climatology
856:November 9,
381:Variability
305:Albuquerque
241:entrainment
206:thermal low
120:Thermal low
1104:Categories
947:: 117–137.
507:References
474:Definition
468:jet stream
334:, and the
300:Dry washes
261:Tiger Fire
186:New Mexico
174:dew points
118:See also:
40:rain over
941:Atmósfera
430:anomalies
404:mesoscale
114:Mechanism
96:Chihuahua
63:, or the
1045:July 23,
1039:Archived
715:June 16,
688:55111148
496:ARkStorm
490:See also
400:synoptic
289:wildfire
239:and the
972:Bibcode
666:Bibcode
533:Bibcode
480:Monsoon
323:basin.
317:arroyos
311:by the
270:Sonoran
251:Effects
217:Pacific
190:Arizona
108:monsoon
88:Durango
84:Sinaloa
38:monsoon
36:Summer
1031:
881:May 7,
852:. NOAA
686:
501:Haboob
330:, the
278:Sahara
274:Mojave
92:Sonora
73:Mexico
59:, the
55:, the
915:(PDF)
907:from
786:(PDF)
684:S2CID
623:from
571:from
1047:2011
1029:ISBN
1008:2022
926:2022
883:2024
858:2022
819:2008
797:2008
769:2008
747:2008
717:2021
351:and
272:and
152:and
122:and
94:and
47:The
980:doi
968:124
674:doi
541:doi
75:.
1106::
1070:.
1049:.
1037:.
978:.
966:.
962:.
943:.
917:.
891:^
874:.
788:.
733:.
708:.
696:^
682:.
672:.
662:20
660:.
656:.
644:^
630:.
595:^
581:.
577:.
555:^
539:.
529:78
527:.
523:.
247:.
90:,
86:,
1010:.
988:.
982::
974::
945:7
928:.
885:.
860:.
821:.
799:.
771:.
749:.
719:.
690:.
676::
668::
549:.
543::
535::
20:)
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
