霜降 貳 (Shuangjiang Follow up for Toronto)

Shuangjiang (Frost Descent):





As for the post earlier explained, Shuangjiang for 2013 is starting from October 23rd and end around November 7th. It is the first appearance of frost after summer solstice of a year in climatic average in relation of ecliptic longitude of the Sun.

This the minimum temperature for CYYZ for 2013 in October.

Day in October,2013	Minimum Temperature
1	10.8
2	11.9
3	7.7
4	15.1
5	13
6	14
7	7
8	6.4
9	6.5
10	7.3
11	6.3
12	6.2
13	8.7
14	6.7
15	5.9
16	10.3
17	9.6
18	7.6
19	3
20	2.7
21	6.8
22	3.1
23	0.7
24	0.9
25	1.6
26	2.4
27	1.7

As you can see on October 24th, 2013 reached the minimum temperature 0.9C.  It's the lowest temperature recorded after summer solstice. It is pretty close, but not frosty enough.

This is the observation on November 24th, 2013 at YYZ:

CYYZ 241200Z 25011KT 15SM FEW020 FEW100 BKN120 02/M00 A2981 RMK SC1AC2AC5 SC TR SLP098
CYYZ 241100Z 25009KT 15SM FEW015 FEW060 01/M01 A2980 RMK SC1SC1 SC TR SLP097
CYYZ 241000Z 27009KT 15SM FEW050 01/M01 A2980 RMK SC1 SC TR SLP096
CYYZ 240900Z 29005KT 15SM SKC 01/M01 A2979 RMK SLP093
CYYZ 240800Z 25007KT 15SM FEW070 01/M01 A2978 RMK AC1 AC TR SLP088
CYYZ 240700Z 25008KT 15SM FEW070 01/M01 A2979 RMK AC1 SLP094
CYYZ 240600Z 25009KT 15SM FEW060 FEW070 02/M00 A2979 RMK SC1AC1 SC TR SLP093
CYYZ 240500Z 26008KT 15SM FEW060 SCT070 01/M01 A2979 RMK SC2AC1 SLP094
CYYZ 240400Z 26010KT 15SM FEW063 FEW075 02/M01 A2981 RMK SC1AC1 SC TR SLP098


Now where is frost?
Could this related to some global warming overall so that the lowest temperature after summer solstice might not be "frosty" enough? Many questions could be raised here, but the lowest temperature got closest to 0 C after summer solstice definitely makes some remark when Ecliptic longitude reaches around 210 degrees to 225 degrees.

Let's look at Oct 28th, 2013 into Oct 29th, 2013 night, 5 days after the day of "Shuangjiang" (210 degree)

CYYZ 291300Z 36005KT 15SM FEW060 FEW240 M01/M05 A3048 RMK SC1CI1 SC TR SLP329
CYYZ 291200Z 36005KT 15SM FEW065 FEW240 M03/M06 A3046 RMK SC1CI1 CI TR SLP323
CYYZ 291100Z 36005KT 15SM SKC M02/M05 A3045 RMK SLP318
CYYZ 291000Z 01005KT 15SM SKC M03/M06 A3045 RMK SLP318
CYYZ 290900Z 36006KT 15SM FEW065 M02/M06 A3044 RMK SC2 SLP314CYYZ 290800Z 36005KT 15SM FEW070 M02/M06 A3043 RMK AC1 SLP312
CYYZ 290700Z 36004KT 15SM FEW070 M01/M05 A3043 RMK AC1 SLP311
CYYZ 290600Z 01006KT 15SM SCT070 M02/M05 A3043 RMK AC3 SLP312
CYYZ 290500Z 36006KT 15SM SKC M01/M05 A3042 RMK SLP308
CYYZ 290400Z 36007KT 15SM SKC M00/M05 A3041 RMK SLP305
CYYZ 290300Z 36009KT 15SM SKC 00/M05 A3041 RMK SLP304

Temperature definitely drop below 0, but relative humidity is marginal for significant frost (RH >= 80%), but it was good enough rather.

All in all, for ecliptic longitude reaches around 210 to 225 degrees, AKA Shuangjiang (Frost Descent), at least this year, we have seen the timing of the lowest temperature that dipped close or below zero fall into this period of time for Toronto area.