Search Results

You are looking at 1 - 10 of 17 items for :

  • Cloud forcing x
  • Monthly Weather Review x
  • Picture of the month x
  • Refine by Access: All Content x
Clear All
Howard B. Bluestein

Klemp (1985), using evidence drawnfrom three-dimensional numerical simulations, haveattributed the formation of the wall cloud to theupward dynamical forcing of cool, negatively buoyant,relatively humid outflow air from a region of precipitation. Bluestein and Parks (1983) have describedthe wall-cloud formation process as the appearance * Present affiliation: On sabbatical leave at the National Centerfor Atmospheric Research, Boulder, CO 80307. The NationalCenter for. Atmospheric Research is

Full access
Gregory S. Forbes and Jonathan H. Merritt

. The vortices are readilydiscernible in satellite imagery, in which they take one of three forms: a miniature comma cloud, a swirl ofcloud bands (resembling a miniature tropical storm) or a swirl of cloud streets. Despite their impressiveappearance in satellite imagery, these vortices are usually relatively mild in comparison with other lake-effectstorms and produce only gusty winds and brief snow squalls as they move onshore. The vortices are accompaniedby a slightly lowered surface pressure and a

Full access
Robert F. Adler, Douglas D. Fenn, and Douglas A. Moore

Weather Central, Offutt Air Force Base, Omafia, NE 68113 (Manuscript received 19 May 1980, in final form 17 November 1980) ABSTRACT A dark, spiral feature is noted in the geosynchronous satellite visible image of the top of a thunder storm which also has a Doppler radar-observed mesocyclone. Although the evidence is not conclusive, the feature may represent cyclonic rotation at cloud top associated with the pre-tornado mesocyclon-.1. Introduction On 20 May 1977

Full access
Klaus P. Hoinka and Dietrich Heimann

east of the front it risesas much as 5 hPa within a strip a few 100 kin wide tothe west of the front. The maximum pressure gradientoccurs close to the north rim of the Pyrenees. (iii) Temperature and frontal weather.' The surfacetemperatur.e drops continuously to the rear of the frontwhile it is rather homogeneous over the prefrontal area.A 6/8 to 8/8 coverage of low strato-cumulus clouds isobserved west of the front while east of it the sky isalmost cloud free. Only weak drizzle occurs near

Full access
Joseph H. Golden

Floridacoast where the prevailing southwesterly troposphericflow interacted with the sea breeze induced by theFlorida peninsula. There have also been numerous reports of funnelclouds over the Everglades west of Miami, in association with lines of cumulus congestus or cumulonimbus clouds (E. J. Zipser, 1970, private communication; Senn, 1978). R. L. Holle (1981, private communication) has noted that dozens of funnel cloudswere observed during the 1971-80 summer FloridaArea Cumulus Experiment (FACE

Full access
Clifford F. Mass and David P. Dempsey

in theimmediate offshore waters ranged from 8- to 10-C.Although western Washington, Oregon and BritishColumbia were virtually cloud free, over the Pacificthere was extensive convective cloudiness that formed20-100 km off the coast as cold, continental airbecame destabilized and moistened by the warmerwater below. Such convection, frequently observedoff the east and Gulf coasts of the United States, isunusual in the Pacific Northwest where offshore flowin winter is relatively infrequent and rarely

Full access
Howard B. Bluestein

extreme instances, to complete cell or system decay, depending on the level of the LFC and the strength of any cap, among other things. In my experience, when a convective system decays, the entire convective cloud base typically erodes from below, leaving behind midlevel cloud debris and an anvil aloft, and sometimes low-level arcus clouds. However, in some circumstances the organization of the convection does not proceed upscale but instead proceeds in the opposite direction. Bluestein and Parks

Full access
T. D. Sikora, G. S. Young, R. C. Beal, and J. B. Edson

composed ofwaves of centimeter-scale wavelength. These kilometer-scale BLSE-induced sea surface roughness patternscan be detected by SAR in the absence of appreciablenon-CMABL sea surface wave forcing phenomena(e.g., heavy slicks that dampen the sea surface roughness field and strong synoptic-scale surface winds thatenhance the sea surface roughness field). Unfortunately, the sea surface SAR imagery acquired in previous studies has not been analyzed withrespect to a concurrent, high

Full access
Neil F. Laird

Indiana ( Fig. 2 ). The cloud band associated with the cold front is also evident in Fig. 1 at 1800 UTC. At the surface, a weak pressure gradient and an inverted trough associated with the region of low pressure over Lake Erie resulted in northerly winds (generally less than 6 m s −1 below 850 hPa) throughout much of the western Great Lakes region. At 850 hPa, a weak trough was situated over the region (see Figs. 3a,b ) with 850-hPa temperatures ranging from about −8.0° to −16.0°C. The synoptic

Full access
Ernani de Lima Nascimento, Gerhard Held, and Ana Maria Gomes

Paulo; the crisscrosses (×) indicate the position of the SBKP METAR site and SBMT upper-air site. A brief analysis of the tornado structure and cloud-base morphology is performed based on selected still images extracted from the videographic documentation; other characteristics of the parent storm are discussed through radar data analysis. In addition, the synoptic-scale conditions that prevailed around the time of the tornadic event are investigated from an ingredients-based perspective ( Doswell

Full access