A Study of Hail Growth Utilizing Observed Storm Conditions

Foote, G. Brant

doi:10.1175/1520-0450(1984)023<0084:asohgu>2.0.co;2

Cited by 92 publications

(69 citation statements)

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“…In that study, the millimeter-sized frozen ''embryos'' that subsequently grew into the largest diameter hailstones were advected into portions of the storm's primary updraft by midlevel storm-relative inflow that curved cyclonically along the southern side of the updraft [Figs. 1 and 3 in Foote (1984)]. In the July 2011 FCL hailstorm, the flanking midlevel inflow occurred along the northern side of the updraft due to the anticyclonically curved stormrelative airflow.…”

supporting

confidence: 55%

“…The storm structure and probable hail growth areas revealed by these dual-Doppler analyses have some mirror-image similarities to those reported during the Westplains, Colorado, hailstorm (Foote 1984). In that study, the millimeter-sized frozen ''embryos'' that subsequently grew into the largest diameter hailstones were advected into portions of the storm's primary updraft by midlevel storm-relative inflow that curved cyclonically along the southern side of the updraft [Figs.…”

mentioning

confidence: 99%

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Observations of the 14 July 2011 Fort Collins Hailstorm: Implications for WSR-88D-Based Hail Detection and Warnings

Kennedy

Rutledge

Dolan

et al. 2014

Weather and Forecasting

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The issuance of timely warnings for the occurrence of severe-class hail (hailstone diameters of 2.5 cm or larger) remains an ongoing challenge for operational forecasters. This study examines the application of two remotely sensed data sources between 0100 and 0400 UTC 14 July 2011 when pulse-type severe thunderstorms occurred in the jurisdiction of the Denver/Boulder National Weather Service (NWS) Forecast Office in Colorado. First, a developing hailstorm was jointly observed by the dual-polarization Colorado State University-University of Chicago-Illinois State Water Survey (CSU-CHILL) research radar and by the operational, single-polarization NWS radar at Denver/Front Range (KFTG). During the time period leading up to the issuance of the initial severe thunderstorm warning, the dual-polarization radar data near the 0 8C altitude contained a positive differential reflectivity Z DR column (indicating a strong updraft lofting supercooled raindrops above the freezing level). Correlation coefficient r HV reductions to ;0.93, probably due to the presence of growing hailstones, were observed above the freezing level in portions of the developing .55-dBZ echo core. Second, data from the National Lightning Detection Network (NLDN), including the locations and polarity of cloud-to-ground (CG) discharges produced by several of the evening's storms, were processed. Some association was found between the prevalence of positive CGs and storms that produced severe hail. The analyses indicate that the use of the dual-polarization data provided by the upgraded Weather Surveillance Radar-1988 Doppler (WSR-88D), in combination with the NLDN data stream, can assist operational forecasters in the real-time identification of thunderstorms that pose a severe hail threat.

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supporting

confidence: 55%

mentioning

confidence: 99%

Observations of the 14 July 2011 Fort Collins Hailstorm: Implications for WSR-88D-Based Hail Detection and Warnings

Kennedy

Rutledge

Dolan

et al. 2014

Weather and Forecasting

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show abstract

“…Numerous studies that investigate the formation of precipitation (especially hail) in severe thunderstorms have been published (e.g., Browning and Foote 1976;Browning 1977;Paluch 1978;Ziegler et al 1983;Foote 1984;Knight and Knupp 1986;Miller et al 1988;Miller et al 1990). However, many of these deal with nonsupercell convection or describe supercells that are not easily classified using the emerging nomenclature discussed above.…”

Section: Hypothesismentioning

confidence: 99%

“…A few findings are pertinent to the present study. For instance, several case studies (Foote 1984;Knight and Knupp 1986;Miller et al 1988) of supercelllike storms clearly indicate that a hailstone usually grows after an embryo reenters the updraft and makes a single pass through it. Hail embryos can be shown to originate in several parts of the storm, including the forward flank, periphery of the updraft, and the upstream convective turrets and stagnation region.…”

Section: Hypothesismentioning

confidence: 99%

“…Instead, it is assumed that wherever the embryos form, it is much more likely that they will reenter the updraft if upper-level storm-relative flow is weak, and less likely if it is strong. This is important because it is quite likely that embryos that descend near the updraft will reenter it owing to the generally convergent flow in the vicinity of the lower one-half of the updraft (Foote 1984).…”

Section: Hypothesismentioning

confidence: 99%

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Variations in Supercell Morphology. Part I: Observations of the Role of Upper-Level Storm-Relative Flow

Rasmussen¹,

Straka²

1998

Mon. Wea. Rev.

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It is hypothesized that the precipitation intensity beneath a supercell updraft is strongly influenced by the amount of hydrometeors that are reingested into the updraft after being transported away in the divergent upperlevel flow of the anvil. This paper presents the results of a climatological analysis of soundings associated with three types of isolated supercells having distinctive precipitation distributions, the so-called classic, low-precipitation (LP), and high-precipitation (HP) storms. It is shown that storm-relative flow at 9-10 km above the ground is strongest in the environments of LP storms, and relatively weak in the environments of HP storms, with classic storms occurring in environments with intermediate magnitudes of upper storm-relative flow. It is plausible that comparatively strong flow in the anvil-bearing levels of LP storms transports hydrometeors far enough from the updraft that they are relatively unlikely to be reingested into the updraft, leading to greatly diminished precipitation formation in the updraft itself. Conversely, the weak upper flow near HP storms apparently allows a relatively large number of hydrometeors to return to the updraft, leading to the generation of relatively large amounts of precipitation in the updraft. It also is apparent that thermodynamic factors such as convective available potential energy, low-level mixing ratio, and mean relative humidity are of lesser importance in determining storm type from a climatological perspective, although important variations in humidity may not be well sampled in this study. This climatological analysis does not directly evaluate the stated hypothesis; however, the findings do indicate that further modeling and microphysical observations are warranted.

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Nonlinear response of hail precipitation rate to environmental moisture content: A real case modeling study of an episodic midlatitude severe convective event

Zhang

et al. 2017

JGR Atmospheres

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The dependence of hail production on initial moisture content in a simulated midlatitude episodic convective event occurred in northeast China on 10–11 June 2005 was investigated using the Weather Research and Forecasting (WRF) model with a double‐moment microphysics scheme where both graupel and hail are considered. Three sensitivity experiments were performed by modifying the initial water vapor mixing ratio profile to 90% (“Q−10%”), 105% (“Q+5%”), and 110% (“Q+10%”) of the initial conditions used for the control simulation. It was found that increasing the initial water vapor content caused the hail and total precipitation rates to increase during the first 5 h. The precipitation response to increasing water vapor content was monotonic for this first episode; however, for the event's second episode, the hail precipitation rate responds to the initial water vapor profile nonlinearly, while the total precipitation rate responds mostly monotonically. In particular, simulation Q+5% achieves the largest hail production rate while simulation Q+10% has the largest total precipitation rate. In contrast, during the second episode simulation Q−10% has the strongest vertical motion, produces the most cloud ice and snow, but has the lowest hail production. Analysis shows that increasing the initial moisture content directly increases the precipitation during the first episode, which subsequently induces a stronger, longer‐lasting cold pool that limits the development of deep convection during the second episode.

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A Study of Hail Growth Utilizing Observed Storm Conditions

Cited by 92 publications

References 0 publications

Observations of the 14 July 2011 Fort Collins Hailstorm: Implications for WSR-88D-Based Hail Detection and Warnings

Observations of the 14 July 2011 Fort Collins Hailstorm: Implications for WSR-88D-Based Hail Detection and Warnings

Variations in Supercell Morphology. Part I: Observations of the Role of Upper-Level Storm-Relative Flow

Nonlinear response of hail precipitation rate to environmental moisture content: A real case modeling study of an episodic midlatitude severe convective event

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