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fires developed as a result of the coupling of the synoptic-scale and mesoscale processes. The polar jet streak upstream of the upper-level trough over the north-central United States strengthened from 0000 UTC 25 October to 1200 UTC 26 October 2003 and evolved from a straight jet into a more anticyclonically curved jet ( Figs. 10a and 10b ). The increase in curvature has an important impact on the force balance that an air parcel may experience when passing through the jet streak; that is, the
fires developed as a result of the coupling of the synoptic-scale and mesoscale processes. The polar jet streak upstream of the upper-level trough over the north-central United States strengthened from 0000 UTC 25 October to 1200 UTC 26 October 2003 and evolved from a straight jet into a more anticyclonically curved jet ( Figs. 10a and 10b ). The increase in curvature has an important impact on the force balance that an air parcel may experience when passing through the jet streak; that is, the
; Hendon and Salby 1994 ). Futhermore, recent processing of observational data ( Mapes et al. 2006 ) suggests the statistical self-similarity of tropical convection on multiple spatiotemporal scales ranging from the mesoscales to the planetary scales. On the other hand, contemporary general circulation models (GCMs) perform poorly both in their ability to resolve convectively coupled synoptic-scale waves and the MJO ( Slingo et al. 1996 ; Lin et al. 2006 ). One conjectured reason for this inadequate
; Hendon and Salby 1994 ). Futhermore, recent processing of observational data ( Mapes et al. 2006 ) suggests the statistical self-similarity of tropical convection on multiple spatiotemporal scales ranging from the mesoscales to the planetary scales. On the other hand, contemporary general circulation models (GCMs) perform poorly both in their ability to resolve convectively coupled synoptic-scale waves and the MJO ( Slingo et al. 1996 ; Lin et al. 2006 ). One conjectured reason for this inadequate
the magnitude of moisture detrainment can also be affected by large-scale processes. Schultz et al. (2007) showed that synoptic-scale processes are important in regulating the strength of the dryline. Stronger drylines were associated with passage of a short-wave trough in the ambient westerlies, favoring surface cyclogenesis, increased confluence, and tighter moisture gradients. Short-wave troughing may also increase the likelihood of convection given the presence of a dryline. Rhea (1966
the magnitude of moisture detrainment can also be affected by large-scale processes. Schultz et al. (2007) showed that synoptic-scale processes are important in regulating the strength of the dryline. Stronger drylines were associated with passage of a short-wave trough in the ambient westerlies, favoring surface cyclogenesis, increased confluence, and tighter moisture gradients. Short-wave troughing may also increase the likelihood of convection given the presence of a dryline. Rhea (1966
selective decay process is associated with vortex mergers within a sea of filamentary structures produced by earlier vortex interactions. At the mesoscale, spiral rainbands and their associated PV structures are one of the most noticeable features associated with tropical cyclones ( Guinn and Schubert 1993 ). At the synoptic scale, trough-thinning phenomena are common in midlatitude baroclinic waves ( Keyser and Shapiro 1986 ; Thorncroft et al. 1993 , hereinafter THM ; Appenzeller et al. 1996 ; Kunz
selective decay process is associated with vortex mergers within a sea of filamentary structures produced by earlier vortex interactions. At the mesoscale, spiral rainbands and their associated PV structures are one of the most noticeable features associated with tropical cyclones ( Guinn and Schubert 1993 ). At the synoptic scale, trough-thinning phenomena are common in midlatitude baroclinic waves ( Keyser and Shapiro 1986 ; Thorncroft et al. 1993 , hereinafter THM ; Appenzeller et al. 1996 ; Kunz
conceptual model begs the following two questions: What processes control the strength of the dryline? Is convection initiation related to the strength of the dryline? The present paper addresses the first question by examining the synoptic-scale influences on dryline intensity. A future paper will address the second question. Finescale mobile surface observations (e.g., Ziegler and Hane 1993 ; Ziegler and Rasmussen 1998 ) and aircraft observations (e.g., Geerts et al. 2006 ) show that the width of
conceptual model begs the following two questions: What processes control the strength of the dryline? Is convection initiation related to the strength of the dryline? The present paper addresses the first question by examining the synoptic-scale influences on dryline intensity. A future paper will address the second question. Finescale mobile surface observations (e.g., Ziegler and Hane 1993 ; Ziegler and Rasmussen 1998 ) and aircraft observations (e.g., Geerts et al. 2006 ) show that the width of
state toward the end of SF ± (day 8) and all the other variables which exhibit plateaus between day 3 and 8, albeit less clearly so for u surf and SML depth. This particularity reflects the long inertia of thermal exchange processes. In sensitivity runs with a longer synoptic intensification plateau (16 instead of 6 days for T p ) SST does not decrease after day 10. This is useful information on the time scale of the system thermal response, which is thus ∼10 days. Momentum adjustments typically
state toward the end of SF ± (day 8) and all the other variables which exhibit plateaus between day 3 and 8, albeit less clearly so for u surf and SML depth. This particularity reflects the long inertia of thermal exchange processes. In sensitivity runs with a longer synoptic intensification plateau (16 instead of 6 days for T p ) SST does not decrease after day 10. This is useful information on the time scale of the system thermal response, which is thus ∼10 days. Momentum adjustments typically
disturbances on mean summer rainfall and found that the north TP disturbance affected precipitation in northeastern China. Liu et al. (2014) studied a lasting heavy precipitation on the north Yangtze–Huai River Basin and suggested that five continuous synoptic-scale disturbance propagations were the main reason. Similarly, the TP<Q1> can have a significant impact on the downstream rainfall by a shorter-period weather process ( Xu 2009 ; Zhang and Xu 2012 ; Zhao et al. 2018 ). However, if the
disturbances on mean summer rainfall and found that the north TP disturbance affected precipitation in northeastern China. Liu et al. (2014) studied a lasting heavy precipitation on the north Yangtze–Huai River Basin and suggested that five continuous synoptic-scale disturbance propagations were the main reason. Similarly, the TP<Q1> can have a significant impact on the downstream rainfall by a shorter-period weather process ( Xu 2009 ; Zhang and Xu 2012 ; Zhao et al. 2018 ). However, if the
weather regimes into different configurations of the effective deformation field at 300 hPa. In the same section, a statistical analysis of the barotropic regeneration process about a BtCR is described. In section 4 , numerical experiments in a forced barotropic model on the sphere are performed. Each experiment consists of adding a synoptic-scale perturbation initially to one of the zonal-like jet configurations found in section 3 that is maintained fixed during the whole simulation. Section 4
weather regimes into different configurations of the effective deformation field at 300 hPa. In the same section, a statistical analysis of the barotropic regeneration process about a BtCR is described. In section 4 , numerical experiments in a forced barotropic model on the sphere are performed. Each experiment consists of adding a synoptic-scale perturbation initially to one of the zonal-like jet configurations found in section 3 that is maintained fixed during the whole simulation. Section 4
colder months partially explains the seasonal trend in lapse rates ( Whiteman et al. 1999 ). Several studies have investigated the impacts of synoptic weather conditions, or large-scale weather patterns, on lapse rates ( Pepin et al. 1999 ; Stahl et al. 2005 ). Pepin et al. (1999) conducted a study in the uplands of northern England evaluating the relationships between lapse rates and solar radiation, humidity, wind speed, and synoptic types. Steeper lapse rates occurred with higher levels of
colder months partially explains the seasonal trend in lapse rates ( Whiteman et al. 1999 ). Several studies have investigated the impacts of synoptic weather conditions, or large-scale weather patterns, on lapse rates ( Pepin et al. 1999 ; Stahl et al. 2005 ). Pepin et al. (1999) conducted a study in the uplands of northern England evaluating the relationships between lapse rates and solar radiation, humidity, wind speed, and synoptic types. Steeper lapse rates occurred with higher levels of
inadequate treatment of the organized hierarchy of tropical processes as a whole (e.g., Hendon and Liebmann 1994 ; Zhang 2005 ; Moncrieff et al. 2007 ; Lau and Waliser 2012 ). This hierarchy involves interactions between organized structures of tropical convection (convectively coupled waves, cloud clusters, etc.) that are defined on a vast range of spatiotemporal scales (synoptic, mesoscale, etc.) and that generate the MJO as their planetary envelope. This organized hierarchy of tropical processes
inadequate treatment of the organized hierarchy of tropical processes as a whole (e.g., Hendon and Liebmann 1994 ; Zhang 2005 ; Moncrieff et al. 2007 ; Lau and Waliser 2012 ). This hierarchy involves interactions between organized structures of tropical convection (convectively coupled waves, cloud clusters, etc.) that are defined on a vast range of spatiotemporal scales (synoptic, mesoscale, etc.) and that generate the MJO as their planetary envelope. This organized hierarchy of tropical processes
