Winter Weather Forecasting throughout the Eastern United States. Part III: The Effects of Topography and the Variability of Winter Weather in the Carolinas and Virginia

Keeter, Kermit K.; Businger, Steven; Lee, Laurence G.; Waldstreicher, Jeff S.

doi:10.1175/1520-0434(1995)010<0042:wwftte>2.0.co;2

Cited by 32 publications

(17 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

Section: Frontal Systems Encountering Mountain Rangessupporting

confidence: 60%

“…[70] Another prime location for low-level cold-air damming occurs on the Atlantic side of the Appalachian Mountains. As described by Keeter et al [1995], it is common for cold air from the northeastern United States to flow south-southwestward along the edge of the Appalachians, while warm moist subtropical air from the Gulf of Mexico and Atlantic Ocean approaches from the lower latitudes ( Figure 40). As shown by Bell and Bosart [1988], this warm air first ascends over the dammed cold air and then the mountains before it can rise over any front that might be approaching from the west (Figure 41).…”

Section: Cold-air Damming and Down-valley Flowmentioning

confidence: 96%

See 1 more Smart Citation

Orographic effects on precipitating clouds

Houze

2012

Reviews of Geophysics

668

470

View full text Add to dashboard Cite

[1] Precipitation over and near mountains is not caused by topography but, rather, occurs when storms of a type that can occur anywhere (deep convection, fronts, tropical cyclones) form near or move over complex terrain. Deep convective systems occurring near mountains are affected by channeling of airflow near mountains, capping of moist boundary layers by flow subsiding from higher terrain, and triggering to break the cap when low-level flow encounters hills near the bases of major mountain ranges. Mesoscale convective systems are triggered by nocturnal downslope flows and by diurnally triggered disturbances propagating away from mountain ranges. The stratiform regions of mesoscale convective systems are enhanced by upslope flow when they move over mountains. In frontal cloud systems, the poleward flow of warm-sector air ahead of the system may rise easily over terrain, and a maximum of precipitating cloud occurs over the first rise of terrain, and rainfall is maximum on ridges and minimum in valleys. If the low-level air ahead of the system is stable, blocking or damming occurs. Shear between a blocked layer and unblocked moist air above favors turbulent overturning, which can accelerate precipitation fallout. In tropical cyclones, the tangential winds encountering a mountain range produce a gravity wave response and greatly enhanced upslope flow. Depending on the height of the mountain, the maximum rain may occur on either the windward or leeward side. When the capped boundary layer of the eye of a tropical cyclone passes over a mountain, the cap may be broken with intense convection resulting.

show abstract

Section: Frontal Systems Encountering Mountain Rangessupporting

confidence: 60%

Section: Cold-air Damming and Down-valley Flowmentioning

confidence: 96%

Orographic effects on precipitating clouds

Houze

2012

Reviews of Geophysics

668

470

View full text Add to dashboard Cite

show abstract

“…Such regions influence the occurrence and persistence of warm and cold air through processes such as cold-air damming and cold-air trapping (see, e.g., Forbes et al 1987;Keeter et al 1995;Rauber et al 2001b;Roebber and Gyakum 2003;Cortinas et al 2004).…”

Section: Precipitation-type Organizationmentioning

confidence: 99%

On the Characteristics of and Processes Producing Winter Precipitation Types near 0°C

Stewart

Thériault

Henson³

2015

Bulletin of the American Meteorological Society

View full text Add to dashboard Cite

This article examines the types of winter precipitation that occur near 0°C, specifically rain, freezing rain, freezing drizzle, ice pellets, snow pellets, and wet snow. It follows from a call by M. Ralph et al. for more attention to be paid to this precipitation since it represents one of the most serious wintertime quantitative precipitation forecasting (QPF) issues. The formation of the many precipitation types involves ice-phase and/or liquid-phase processes, and thresholds in the degree of melting and/or freezing often dictate the types occurring at the surface. Some types can occur simultaneously so that, for example, ensuing collisions between supercooled raindrops and ice pellets that form ice pellet aggregates can lead to substantial reductions in the occurrence of freezing rain at the surface, and ice crystal multiplication processes can lead to locally produced ice crystals in the subfreezing layer below inversions. Highly variable fall velocities within the background temperature and wind fields of precipitation-type transition regions lead to varying particle trajectories and significant alterations in the distribution of precipitation amount and type at the surface. Physically based predictions that account for at least some of the phase changes and particle interactions are now in operation. Outstanding issues to be addressed include the impacts of accretion on precipitation-type formation, quantification of melting and freezing rates of the highly variable precipitation, the consequences of collisions between the various types, and the onset of ice nucleation and its effects. The precipitation physics perspective of this article furthermore needs to be integrated into a comprehensive understanding involving the surrounding and interacting environment.

show abstract

“…However, once the cold front passes, upslope snow commences in association with the cold and moist low-level northwest flow. Snow associated with a moist (e.g., Gulf origin) southwesterly low-level flow ahead of an eastward-moving disturbance west or north of the area (NEb) constitutes a second Miller Type A and Miller Type B cyclones are responsible for most of the big snowstorms across the southern Appalachians, mid-Atlantic, and into the northeastern U.S. (Miller, 1946;Kocin and Ucellini, 1990;Keeter et al, 1995;Mote et al, 1997) and constitute the next four synoptic classes. All of the 20 major snowstorms in the northeastern U.S. analyzed by Kocin and Ucellini (1990) were of the Miller Type A or B variety.…”

Section: Introductionmentioning

confidence: 99%

Synoptic Classification of Snowfall Events in the Great Smoky Mountains, USA

Perry

Konrad²,

Hotz

et al. 2010

Physical Geography

Self Cite

View full text Add to dashboard Cite

Mean annual snowfall in the Great Smoky Mountains National Park (GSMNP) exhibits considerable spatial variability, ranging from 30 cm in the valleys to 254 cm at higher elevations. Snowfall can be tied to a variety of synoptic classes (e.g., Miller A or B cyclones, 500 hPa cutoff lows), but the frequency and significance of different synoptic classes have not been fully assessed, particularly at higher elevations. In this paper, we manually classify all snowfall events during the period 1991 to 2004 according to a synoptic classification scheme, calculate mean annual snowfall by 850 hPa wind direction and synoptic class, and develop composite plots of various synoptic fields. Hourly observations from nearby first-order stations and 24 hr snowfall totals from five sites within the GSMNP are used to define snowfall events. NCEP/NCAR reanalysis data are used to develop composite plots of various synoptic fields for cyclones passing south and then east of the area (e.g., Miller A cyclones). Results indicate that over 50% of the mean annual snowfall at higher elevations occurs in association with low-level northwest flow, and that Miller A cyclones contribute the greatest amount to mean annual snowfall at all elevations. [

show abstract

Winter Weather Forecasting throughout the Eastern United States. Part III: The Effects of Topography and the Variability of Winter Weather in the Carolinas and Virginia

Cited by 32 publications

References 0 publications

Orographic effects on precipitating clouds

Orographic effects on precipitating clouds

On the Characteristics of and Processes Producing Winter Precipitation Types near 0°C

Synoptic Classification of Snowfall Events in the Great Smoky Mountains, USA

Contact Info

Product

Resources

About