SATELLITE PICTURES AND METEOROLOGICAL ANALYSES OF A DEVELOPING LOW IN THE CENTRAL UNITED STATES¹

Abstract

TIROS I satellite pictures for a 3-day period about, :t developing "Low vysterrl" over the central United States are shown. Cloud distribut,ion about surface fronts and upper-air troughs was examincd and compared to the "ideal" (classical) distribution. The pictures and analyses reveal t,hat cloud patterns w e r e significantly changed by strong subsidence and advection of dry air along a lo~v-levc~l wiud maxirrlum. The cloud patterns whcn compared to the 600-mb. vertical motions computed routinely hy the Joint Xnmerical Wvathcr Prediction Vnit showed only partial agreement. A strong relationship hetween low cloud cover and surface rc1:ttivr humidity \$as found; thjs relationship may be useful under certain conditions in determining the stability of the air over areas where upper-air data are sparse.

A SYNTHESIS OF INTERPRETATIONS OF EXTRATROPICAL VORTEX PATTERNS AS SEEN BY TIROS1

“…Such convective cloudiness usually tends to have some breaks in it. Conditions along these lines were noted by Timchalk and Hubert [24].…”

“…Rutherford [all states it corresponds to subsiding air west of the trough. Tiinclialk and Hubert [24] find both subsidence and the dry air equatorward of the low-level wind niasinium. Leese [13], however, ascribes the clear area to advection and not to direct subsidence.…”

“…On the other hand, also as n corollary to the relatively insignificant appearance of this stage, tlie wave inay often be hidden b y ti more extensive cloud sheet [2]. (The case discussed by Timchalk and Hubert [24] seems to be one such.) This is illustrated in figure 2.…”

“…'I'imchrtlk ihnd Hubert [24] found that, in general, the surfwe reliitive humidity piitterns were well correliitcd with the distribution of low clouds, but that in some regions st:rbility considerations prevented low cloud formation in spite of adeyu:ite humidity.…”

A Meteorological Study of Cold Clouds as Related to Satellite Infrared Horizon Sensors

“…United States Figure 22 represents TIROS I satellite photographs of another extratropical cyclone which was extensively studied previously (Timchalk and Hubert, 1961) and which was centered in the central United States.…”