• Benton, G. S., and M. A. Estoque, 1954: Water-vapor transfer over the North American continent. J. Meteor.,11, 462–477.

  • Blackadar, A. K., 1957: Boundary-layer wind maxima and their significance for the growth of nocturnal inversions. Bull. Amer. Meteor. Soc.,38, 283–290.

  • Blackmon, M. L., V.-H. Lee, and J. M. Wallace, 1984: Horizontal structure of 500 mb height fluctuations with long, intermediate and short time scales. J. Atmos. Sci.,41, 961–979.

  • Bloom, S. C., L. L. Takacs, A. M. da Silva, and D. Ledvina, 1996: Data assimilation using incremental analysis updates. Mon. Wea. Rev.,124, 1256–1271.

  • Bonner, W. D., 1966: Case study of thunderstorm activity relation to the low-level jet. Mon. Wea. Rev.,94, 167–178.

  • ——, 1968: Climatology of the low-level jet. Mon. Wea. Rev.,96, 833–850.

  • ——, and J. Paegle, 1970: Diurnal variations in the boundary-layer winds over the south central United States in summer. Mon. Wea. Rev.,98, 735–744.

  • Bowen, B. M., 1996: Rainfall and climate variation over a sloping New Mexico plateau during the North American monsoon. J. Climate,9, 3432–3442.

  • Browning, K. A., and C. W. Pardoe, 1973: Structure of low-level jet streams ahead of midlatitude cold fronts. Quart. J. Roy. Meteor. Soc.,99, 619–638.

  • Carlson, T. N., 1991: Mid-Latitude Weather Systems. Harper Collins Academic, 507 pp.

  • Chang, F.-C., and J. M. Wallace, 1987: Meteorological conditions during heat waves and droughts in the United States Great Plains. Mon. Wea. Rev.,115, 1253–1269.

  • Chen, T.-C., and J. A. Kpaeyeh, 1993: The synoptic-scale environment associated with the low-level jet of the Great Plains. Mon. Wea. Rev.,121, 416–420.

  • ——, M.-C. Yen, and S. Schubert, 1996: Hydrological processes associated with cyclonic systems over the United States. Bull. Amer. Meteor. Soc.,77, 1557–1567.

  • Harrold, T. W., 1973: Mechanisms influencing the distribution of precipitation within baroclinic disturbances. Quart. J. Roy. Meteor. Soc.,99, 232–251.

  • Harshvardhan, R. Davies, D. A. Randall, and T. G. Corsetti, 1987: A fast radiation parameterization for atmospheric circulation models. J. Geophys. Res.,92, 1009–1016.

  • Helfand, H. M., and J. C. Labraga, 1988: Design of a non-singular level 2.5 second-order closure model for the prediction of atmospheric turbulence. J. Atmos. Sci.,45, 113–132.

  • ——, and S. D. Schubert, 1995: Climatology of the simulated Great Plains low-level jet and its contribution to the continental moisture budget of the United States. J. Climate,8, 784–806.

  • Higgins, R. W., J. E. Janowiak, and Y. Yao, 1996a: A gridded hourly precipitation data base for the United States (1963–93). Atlas No. 1., NCEP/Climate Prediction Center, 47 pp.

  • ——, K. C. Mo, and S. D. Schubert, 1996b: The moisture budget of the central United States in spring as evaluated in the NCEP/NCAR and the NASA/DAO reanalyses. Mon. Wea. Rev.,124, 939–963.

  • ——, Y. Yao, E. S. Yarosh, J. E. Janowiak, and K. C. Mo, 1997: Influence of the Great Plains low-level jet on the summertime precipitation and moisture transport over the central United States. J. Climate,10, 481–507.

  • Hoecker, W. J., 1963: Three southerly low-level jet systems delineated by the Weather Bureau special pibal network of 1961. Mon. Wea. Rev.,91, 573–582.

  • Hovanec, R. D., and L. H. Horn, 1975: Static stability and the 300 mb isotach field in the Colorado cyclonetic area. Mon. Wea. Rev.,103, 628–638.

  • Lindzen, R. S., 1967: Thermally driven diurnal tide in the atmosphere. Quart. J. Roy. Meteor. Soc.,93, 18–42.

  • Lyon, B., and R. Dole, 1995: A diagnostic comparison of the 1980 and 1988 U.S. summer heat wave–droughts. J. Climate,8, 1658–1675.

  • Maddox, R. A., 1983: Large-scale meteorological conditions associated with midlatitude, mesoscale convective complexes. Mon. Wea. Rev.,111, 1475–1493.

  • Meyers, S. D., B. G. Kelly, and J. J. O’Brien, 1993: An introduction to wavelet analysis in oceanography and meteorology: With application to the dispersion of Yanai waves. Mon. Wea. Rev.,121, 2858–2878.

  • Min, W., and S. Schubert, 1997: The climate signal in regional moisture fluxes: A comparison of three global data assimilation products. J. Climate,10, 2623–2642.

  • Molod, A., H. M. Helfand, and L. L. Takacs, 1996: The climatology of parameterized physical processes in the GEOS-1 GCM and their impact on the GEOS-1 Data Assimilation System. J. Climate,9, 764–785.

  • Moorthi, S., and M. J. Suarez, 1992: Relaxed Arakawa–Schubert: A parameterization of moist convection for general circulation models. Mon. Wea. Rev.,120, 978–1002.

  • Namias, J., 1955: Some meteorological aspects of drought with special reference to the summers of 1952–1954 over the United States. Mon. Wea. Rev.,83, 199–205.

  • ——, 1982: Anatomy of Great Plains protracted heat waves (especially the 1980 U.S. summer drought). Mon. Wea. Rev.,110, 824–838.

  • Newton, C. W., 1967: Severe convective storms. Advances in Geophysics, Vol. 12, Academic Press, 257–308.

  • Oglesby, R. J., 1991: Springtime soil moisture, natural climatic variability, and North American drought as simulated by the NCAR Community Climate Model 1. J. Climate,4, 890–897.

  • ——, K. A. Maasch, and B. Saltzman, 1989: Glacial meltwater cooling of the Gulf of Mexico: GCM implications for Holocene and present-day climate. Climate Dyn.,3, 115–133.

  • Paegle, J., 1984: Topographically bound low-level circulations. Riv. Meteor. Aeronaut.,44, 113–125.

  • Pfaendtner, J., S. Bloom, D. Lamich, M. Seablom, M. Sienkiewicz, J. Stobie, and A. da Silva, 1995: Documentation of the Goddard Earth Observing System (GEOS) Data Assimilation System-Version 1. NASA Tech. Memo. 104606, Vol. 4, 44 pp. [Available from Goddard Space Flight Center, Greenbelt, MD 20771.].

  • Pitchford, K. L., and J. London, 1962: The low-level jet as related to nocturnal thunderstorms over midwest United States. J. Appl. Meteor.,1, 43–47.

  • Rasmusson, E. M., 1967: Atmospheric water vapor transport and the water balance of North America: Part I. Characteristics of the water vapor flux field. Mon. Wea. Rev.,95, 403–426.

  • Reiter, E. R., 1969: Tropopause circulation and jet streams. World Survey of Climatology, Climate of the Free Atmosphere, D. F. Rex, Ed., Vol. 4, Elsevier, 85–193.

  • Roads, J. O., S.-C. Chen, A. K. Guetter, and K.-P. Georgakakos, 1994:Large-scale aspects of the United States hydrological cycle. Bull. Amer. Meteor. Soc.,75, 1589–1610.

  • Roebber, P. J., 1984: Statistical analysis and updated climatology of explosive cyclones. Mon. Wea. Rev.,112, 1577–1589.

  • Schemm, J.-K., S. Schubert, J. Terry, S. Bloom, and Y. Sud, 1992: Estimates of monthly mean soil moisture for 1979–89. NASA Tech. Memo. 104571, 252 pp. [Available from Goddard Space Flight Center, Greenbelt, MD 20771.].

  • Schubert, S., and Y. Chang, 1996: An objective method for inferring sources of model error. Mon. Wea. Rev.,124, 325–340.

  • ——, J. Pfaendtner, and R. Rood, 1993: An assimilated dataset for earth science applications. Bull. Amer. Meteor. Soc.,74, 2331–2342.

  • ——, and Coauthors, 1995: A multiyear assimilation with the GEOS-1 system: Overview and results. NASA Tech. Memo. 104606, Vol. 6, 183 pp. [Available from Goddard Space Flight Center, Greenbelt, MD 20771.].

  • Stensrud, D. J., 1996: Importance of low-level jets to climate: A review. J. Climate,9, 1698–1711.

  • Suarez, M. J., and L. L. Takacs, 1995: Documentation of the Aries-GEOS dynamical core: Version 2. NASA Tech. Memo. 104606, Vol. 5, 45 pp. [Available from Goddard Space Flight Center, Greenbelt, MD 20771.].

  • Sud, Y., and A. Molod, 1988: The roles of dry convection, cloud-radiation feedback processes and the influence of recent improvements in the parameterization of convection in the GLA GCM. Mon. Wea. Rev.,116, 2366–2387.

  • Takacs, L. L., and M. J. Suarez, 1996: Dynamical aspects of climate simulations using the GEOS General Circulation Model. NASA Tech. Memo. 104606, Vol. 10, 56 pp. [Available from Goddard Space Flight Center, Greenbelt, MD 20771.].

  • ——, A. Molod, and T. Wang, 1994: Goddard Earth Observing System (GEOS) General Circulation Model (GCM) Version 1. NASA Tech. Memo. 104606, Vol. 1, 100 pp. [Available from Goddard Space Flight Center, Greenbelt, MD 20771.].

  • Uccellini, L. W., and D. R. Johnson, 1979: The coupling of upper and lower tropospheric jet streams and implications for the development of severe convective storms. Mon. Wea. Rev.,107, 682–703.

  • Wallace, J. M., 1975: Diurnal variations in precipitation and thunderstorm frequency over the conterminous United States. Mon. Wea. Rev.,103, 406–419.

  • ——, and F. R. Hartranft, 1969: Diurnal wind variations, surface to 30 kilometers. Mon. Wea. Rev.,97, 446–455.

  • Weng, H., and K.-M. Lau, 1994: Wavelets, period doubling, and time-frequency localization with application to organization of convection over the tropical western Pacific. J. Atmos. Sci.,51, 2523–2541.

  • Winkler, J. A., B. R. Skeeter, and P. D. Yamamoto, 1988: Seasonal variations in the diurnal characteristics of heavy hourly precipitation across the United States. Mon. Wea. Rev.,116, 1641–1658.

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Subseasonal Variations in Warm-Season Moisture Transport and Precipitation over the Central and Eastern United States

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  • 1 Data Assimilation Office, Laboratory for Atmospheres, NASA/Goddard Space Flight Center, Greenbelt, Maryland
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Abstract

Subseasonal variations in warm-season (May–August) precipitation over the central and eastern United States are shown to be strongly linked to variations in the moisture entering the continent from the Gulf of Mexico within a longitudinally confined “channel” (referred to here as the Texas corridor or TC). These variations reflect the development of low-level southerly wind maxima (or jets) on a number of different timescales in association with distinct subcontinental and larger-scale phenomena. On the diurnal timescale, the TC moisture flux variations are tied to the development of the Great Plains low-level jet. The composite nighttime anomalies are characterized by a strong southerly moisture flux covering northeast Mexico and the southern Great Plains, and enhanced boundary layer convergence and precipitation over much of the upper Great Plains. The strongest jets tend to be associated with an anomalous surface low over the Great Plains, reflecting a predilection for periods when midlatitude weather systems are positioned to produce enhanced southerly flow over this region. On subsynoptic (2–4 days) timescales the TC moisture flux variations are associated with the development and evolution of a warm-season lee cyclone. These systems, which are most prevalent during the early part of the warm season (May and June), form over the central Great Plains in association with an upper-level shortwave and enhanced upper-tropospheric cross-mountain westerly flow. A low-level southerly wind maximum or jet develops underneath and perpendicular to the advancing edge of enhanced midtropospheric westerlies. The clash of anomalous southerly moisture flux and a deep intrusion of anomalous northerly low-level winds results in enhanced precipitation eventually stretching from Texas to the Great Lakes. On synoptic (4–8 days) timescales the TC moisture flux variations are associated with the propagation and intensification of a warm-season midlatitude cyclone. This system, which also occurs preferentially during May and June, develops offshore and intensifies as it crosses the Rocky Mountains and taps moisture from the Gulf of Mexico. Low-level southerly wind anomalies develop parallel to the mid- and upper-level winds on the leading edge of the trough. Widespread precipitation anomalies move with the propagating system with reduced rainfall occurring over the anomalous surface high, and enhanced rainfall occurring over the anomalous surface low. On still longer timescales (8–16 days) the variations in the TC moisture transport are tied to slow eastward-moving systems. The evolution and structure of the mid- and low-level winds are similar to those of the synoptic-scale system with, however, a somewhat larger zonal scale and spatially more diffuse southerly moisture flux and precipitation anomalies.

* Additional affiliation: General Sciences Corporation, a subsidiary of Science Applications International Corporation, Laurel, Maryland.

Corresponding author address: Dr. Siegfried D. Schubert, NASA/Goddard Space Flight Center, Mail Code 910.3, Greenbelt, MD 20771.

Abstract

Subseasonal variations in warm-season (May–August) precipitation over the central and eastern United States are shown to be strongly linked to variations in the moisture entering the continent from the Gulf of Mexico within a longitudinally confined “channel” (referred to here as the Texas corridor or TC). These variations reflect the development of low-level southerly wind maxima (or jets) on a number of different timescales in association with distinct subcontinental and larger-scale phenomena. On the diurnal timescale, the TC moisture flux variations are tied to the development of the Great Plains low-level jet. The composite nighttime anomalies are characterized by a strong southerly moisture flux covering northeast Mexico and the southern Great Plains, and enhanced boundary layer convergence and precipitation over much of the upper Great Plains. The strongest jets tend to be associated with an anomalous surface low over the Great Plains, reflecting a predilection for periods when midlatitude weather systems are positioned to produce enhanced southerly flow over this region. On subsynoptic (2–4 days) timescales the TC moisture flux variations are associated with the development and evolution of a warm-season lee cyclone. These systems, which are most prevalent during the early part of the warm season (May and June), form over the central Great Plains in association with an upper-level shortwave and enhanced upper-tropospheric cross-mountain westerly flow. A low-level southerly wind maximum or jet develops underneath and perpendicular to the advancing edge of enhanced midtropospheric westerlies. The clash of anomalous southerly moisture flux and a deep intrusion of anomalous northerly low-level winds results in enhanced precipitation eventually stretching from Texas to the Great Lakes. On synoptic (4–8 days) timescales the TC moisture flux variations are associated with the propagation and intensification of a warm-season midlatitude cyclone. This system, which also occurs preferentially during May and June, develops offshore and intensifies as it crosses the Rocky Mountains and taps moisture from the Gulf of Mexico. Low-level southerly wind anomalies develop parallel to the mid- and upper-level winds on the leading edge of the trough. Widespread precipitation anomalies move with the propagating system with reduced rainfall occurring over the anomalous surface high, and enhanced rainfall occurring over the anomalous surface low. On still longer timescales (8–16 days) the variations in the TC moisture transport are tied to slow eastward-moving systems. The evolution and structure of the mid- and low-level winds are similar to those of the synoptic-scale system with, however, a somewhat larger zonal scale and spatially more diffuse southerly moisture flux and precipitation anomalies.

* Additional affiliation: General Sciences Corporation, a subsidiary of Science Applications International Corporation, Laurel, Maryland.

Corresponding author address: Dr. Siegfried D. Schubert, NASA/Goddard Space Flight Center, Mail Code 910.3, Greenbelt, MD 20771.

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