Improved VAS regression soundings of mesoscale temperature structure observed during the 1982 atmospheric variability experiment

An Atmospheric Variability Experiment (AVE) was conducted over the central U.S. in the spring of 1982, collecting radiosonde date to verify mesoscale soundings from the VISSR Atmospheric Sounder (VAS) on the GOES satellite. Previously published VAS/AVE comparisons for the 6 March 1982 case found that the satellite retrievals scarcely detected a low level temperature inversion or a mid-tropospheric cold pool over a special mesoscale radiosonde verification network in north central Texas. The previously published regression and physical retrieval algorithms did not fully utilize VAS' sensitivity to important subsynoptic thermal features. Therefore, the 6 March 1982 case was reprocessed adding two enhancements to the VAS regression retrieval algorithm: (1) the regression matrix was determined using AVE profile data obtained in the region at asynoptic times, and (2) more optimistic signal-to-noise statistical conditioning factors were applied to the VAS temperature sounding channels. The new VAS soundings resolve more of the low level temperature inversion and mid-level cold pool. Most of the improvements stems from the utilization of asynoptic radiosonde observations at NWS sites. This case suggests that VAS regression soundings may require a ground-based asynoptic profiler network to bridge the gap between the synoptic radiosonde network and the high resolution geosynchronous satellite observations during the day

Atlas of TOMS ozone data collected during the Genesis of Atlantic Lows Experiment (GALE), 1986

Data from the TOMS (Total Ozone Mapping Spectrometer) instrument aboard the Nimbus-7 satellite were collected daily in real time during the GALE (Genesis of Atlantic Lows Experiment) from January 15 through March 15, l986. The TOMS ozone data values were processed into GEMPAK format and transferred from the Goddard Space Flight Center to GALE operations in Raleigh-Durham, NC, in as little as three hours for use, in part, to direct aircraft research flights recording in situ measurements of ozone and water vapor in areas of interest. Once in GEMPAK format, the ozone values were processed into gridded form using the Barnes objective analysis scheme and contour plots of the ozone created. This atlas provides objectively analyzed contour plots of the ozone for each of the sixty days of GALE as well as four-panel presentations of the ozone analysis combined on the basis of GALE Intensive Observing Periods (IOP's)

The President's Day Cyclone of 18-19 February 1979: Synoptic Overview and Analysis of the Subtropical Jet Streak Influencing the Pre-Cyclogenetic Period

The Presidents' Day cyclone of 18-19 February 1979 was an intense and rapidly developing storm which produced heavy snowfall along the East Coast of the United States. An analysis of the cyclone is presented which isolates three jet streaks that appear to have played important roles in the development of two separate areas of heavy snow. One area of heavy snow developed prior to cyclogenesis and is linked, in part, to an increasingly unbalanced subtropical jet streak (STJ) and a noticeably ageostrophic low-level jet. The second area of heavy snow developed in conjunction with the explosive cyclogenesis off the East Coast as a polar jet streak and midtropospheric trough propagated toward the coastal region from the north-central United States. This paper examines the STJ in detail. The maximum wind speeds associated with the STJ increased by 15 to 20 m S-I between 1200 GMT 17 and 1200 GMT 18 February 1979 as the jet propagated from the south-central toward the eastern United States. During the 24 h period, the flow in the STJ became increasingly supergeostrophic and apparently unbalanced. Ageostrophic wind speeds increased to greater than 30 m S-I, with a significant cross-contour component directed toward lower values of the Montgomery streamfunction, as the flow along the STJ became increasingly divergent with time. The increased wind speed, ageostrophic flow, and divergence along the axis of the STJ are linked to the increasing confluence in the entrance region of the jet streak and the decreasing wavelength of the trough-ridge system in which the jet streak was embedded. The upper level divergence and upward vertical motion near the axis of the STJ along with the moisture transport associated with the LU are found to be important factors in the development of the first area of heavy snow

The Presidents' Day cyclone of 18–19 February 1979: Influence of upstream trough amplification and associated tropopause folding on rapid cyclogenesis

The Presidents' Day cyclone of 18-19 February, 1979 is analyzed based on conventional radiosonde data, infrared and visible satellite imagery, water vapor images and ozone measurement. The well-known synoptic-scale characteristics of the PJ-trough system are described, and evidence for the development of the tropopause fold are presented. Processes contributing to the formation of the fold are discussed in terms of an evaluation of the Sawyer-Eliassen circulation equation and a diagnostic evaluation of the ageostrophic winds and vertical motion near the polar jet streak. The documentation of stratospheric extrusions and their possible role in cyclogenesis is reviewed, and Eulerian and Lagrangian diagnostics are used to establish a connection between the tropopause fold associated with the polar jet streak and rapid cyclogenesis along the East Coast. Conservation of potential vorticity expressed in isentropic coordinates is used as a constraint from which to view cyclogenesis

The national earth system prediction capability: coordinating the giant

The article of record as published may be found at http://dx.doi.org/10.1175/BAMS-D-16-0002.1A five-agency strategy to coordinate and accelerate the national numerical environmental prediction capability is discussed