Strange conditions on 10m WSPR Saturday 26 April

While doing some other tasks on Saturday I let my Ultimate 3 transmitter run for the whole day from 1200z at 1W output with the help of an external PA. The results were very strange. Nothing, then lots of Oceania with a few Americans at the start:-

Timestamp	Call	MHz	SNR	Drift	Grid	Pwr	Reporter	RGrid	km	az
2014-04-27 02:30	WW2R	28.126119	-21	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 02:12	WW2R	28.126093	-17	0	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-27 02:12	WW2R	28.126119	-26	0	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 02:00	WW2R	28.126077	-23	1	EM13pc	1	VK5ST	PF95ml	14929	252
2014-04-27 01:48	WW2R	28.126104	-16	0	EM13pc	1	ZL1AML	RF73gb	12040	237
2014-04-27 01:48	WW2R	28.126119	-26	0	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 01:36	WW2R	28.126077	-16	1	EM13pc	1	VK5ST	PF95ml	14929	252
2014-04-27 01:36	WW2R	28.126093	-26	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-27 01:30	WW2R	28.126096	-26	0	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-27 01:30	WW2R	28.126119	-21	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 01:30	WW2R	28.126104	-17	1	EM13pc	1	ZL1AML	RF73gb	12040	237
2014-04-27 01:30	WW2R	28.126093	-23	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-27 01:18	WW2R	28.126104	-16	1	EM13pc	1	ZL1AML	RF73gb	12040	237
2014-04-27 01:12	WW2R	28.126103	-13	1	EM13pc	1	ZL1AML	RF73gb	12040	237
2014-04-27 01:12	WW2R	28.126092	-25	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-27 01:12	WW2R	28.126118	-20	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 01:00	WW2R	28.126098	-27	0	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-27 01:00	WW2R	28.126096	-25	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-27 00:54	WW2R	28.126119	-26	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 00:54	WW2R	28.126093	-25	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-27 00:54	WW2R	28.126096	-23	1	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-27 00:48	WW2R	28.126097	-19	1	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-27 00:48	WW2R	28.126120	-19	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 00:48	WW2R	28.126105	-13	1	EM13pc	1	ZL1AML	RF73gb	12040	237
2014-04-27 00:42	WW2R	28.126120	-19	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 00:42	WW2R	28.126096	-17	1	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-27 00:36	WW2R	28.126093	-22	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-27 00:36	WW2R	28.126095	-24	1	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-27 00:36	WW2R	28.126118	-17	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 00:18	WW2R	28.126120	-19	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 00:18	WW2R	28.126096	-21	1	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-27 00:18	WW2R	28.126093	-24	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-27 00:12	WW2R	28.126121	-20	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-27 00:12	WW2R	28.126098	-20	0	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-27 00:12	WW2R	28.126119	-29	1	EM13pc	1	VK5ADE	PF95he	14974	252
2014-04-27 00:12	WW2R	28.126095	-17	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 23:54	WW2R	28.126119	-20	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 23:42	WW2R	28.126095	-27	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 23:42	WW2R	28.126098	-22	1	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-26 23:42	WW2R	28.126120	-17	0	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 23:36	WW2R	28.126121	-22	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 23:36	WW2R	28.126096	-25	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 23:36	WW2R	28.126099	-23	1	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-26 23:36	WW2R	28.126104	-18	1	EM13pc	1	ZL1AML	RF73gb	12040	237
2014-04-26 23:30	WW2R	28.126097	-15	1	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-26 23:30	WW2R	28.126102	-16	1	EM13pc	1	ZL1AML	RF73gb	12040	237
2014-04-26 23:30	WW2R	28.126117	-23	1	EM13pc	1	VK5ADE	PF95he	14974	252
2014-04-26 23:30	WW2R	28.126093	-27	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 23:30	WW2R	28.126120	-16	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 23:24	WW2R	28.126121	-11	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 23:24	WW2R	28.126099	-18	1	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-26 23:24	WW2R	28.126096	-28	0	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 23:18	WW2R	28.126094	-23	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 23:18	WW2R	28.126102	-12	1	EM13pc	1	ZL1AML	RF73gb	12040	237
2014-04-26 23:18	WW2R	28.126097	-21	1	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-26 23:12	WW2R	28.126119	-14	0	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 23:12	WW2R	28.126092	-24	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 23:12	WW2R	28.126096	-25	0	EM13pc	1	VK5EI	PF95gc	14984	252
2014-04-26 23:06	WW2R	28.126122	-14	0	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 23:06	WW2R	28.126095	-25	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 23:00	WW2R	28.126093	-26	0	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 22:54	WW2R	28.126096	-17	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 22:54	WW2R	28.126103	-25	-1	EM13pc	1	VK3DXE	QF21nv	14500	246
2014-04-26 22:54	WW2R	28.126123	-15	0	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 22:42	WW2R	28.126096	-27	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 22:42	WW2R	28.126114	-21	0	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 22:36	WW2R	28.126104	-13	0	EM13pc	1	ZL1AML	RF73gb	12040	237
2014-04-26 22:36	WW2R	28.126096	-26	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 22:36	WW2R	28.126114	-11	1	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 22:24	WW2R	28.126094	-25	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 22:24	WW2R	28.126099	-23	0	EM13pc	1	K9AN	EN50wc	1091	42
2014-04-26 22:24	WW2R	28.126148	-13	0	EM13pc	1	N9XY	EM84ml	1279	79
2014-04-26 22:24	WW2R	28.126112	-18	0	EM13pc	1	VK3AMW	QF22ir	14513	247
2014-04-26 22:18	WW2R	28.126147	-19	1	EM13pc	1	N9XY	EM84ml	1279	79
2014-04-26 22:12	WW2R	28.126150	-23	0	EM13pc	1	N9XY	EM84ml	1279	79
2014-04-26 22:06	WW2R	28.126096	-20	0	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 22:00	WW2R	28.126099	-23	0	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 21:54	WW2R	28.126098	-20	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 21:48	WW2R	28.126099	-26	1	EM13pc	1	VK4ZBV	QG62ml	13413	255
2014-04-26 19:36	WW2R	28.126098	-23	1	EM13pc	1	WP4JT	FK68	3368	111