WASHINGTON, DCExperts at the Naval Observatory report that April, as it has every year at this time since records were kept, is progressing to an end. 'We have had 26 perfectly acceptable diurnal periods, or 'days,' of April thus far,' said NOAA meteorologist Carl Whittaker. 'And we anticipate exactly four more before the immediate beginning of May. Please adjust all analog and digital temporal recording devices appropriately.' Whittaker also noted that, for laymen, May would progress in much the same fashion as April, excepting the addition of a 31st day which is traditionally appended at the month's conclusion. 