Accession Number:

ADA218161

Title:

Anatomy of a 'Bomb' Diagnostic Investigation of Explosive Cyclogenesis Over the Mid-West United States

Descriptive Note:

Master's thesis

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s):

Report Date:

1989-01-01

Pagination or Media Count:

108.0

Abstract:

The physical processes responsible for the explosive cyclogenesis that took place over the mid-west U.S. on 14-15 December 1987. This system is worthy of study because of its explosive development central pressure dropped 27 mb in 18 hours totally over land. Statistical studies show that explosive development of land-locked cyclones or bombs are rare events. During the initial phase 1800 UTC 14 Dec to 0400 UTC 15 Dec the cyclone experienced a pressure fall of 1 mbhr. Cyclogenesis was initiated near Houston, at 1800 UTC 14 Dec. Convection developed in the vicinity of the cyclone center and extended along the cold front with time. A low-level jet aided cyclogenesis through advection of warm-moist Gulf air into the region of developing low pressure, coincidental with superposition of the left exit region of a subtropical jet over the surface front. The second and most rapid phase of explosive development began when a progressive short-wave trough, associated with the polar jet, moved out of the southern Rockies and approached within 400 km of the cyclone center. This rapid phase of development pressure fall of 2.5 mbhr from 0600 to 1200 UTC 15 Dec coincides with 1 merging of the polar and subtropical jets aloft 2 very strong advection of cyclonic mid-tropospheric vorticity over the cyclone center, 3 vertical coupling of the ageostrophic motion fields associated with the upper and lower level jets and 4 intrusion of stratospheric air down to the 700 mb level enhancing the generation of cyclonic vorticity. Theses.

Subject Categories:

  • Meteorology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE