Quiet time coming, knock on wood

[Margie Kieper]

We're approaching the quietest time of the year as far as global TC activity. The longest periods have all started about a month from now, but a quiescent period could start earlier -- unless you believe the GFS long-term take on a possible subtropical storm around the Bahamas and Bermuda in a week.

Here are the stats on the longest documented times between 1964 and 2004 with no active tropical cyclones, that I calculated in January, using the NHC and JTWC best tracks (at the time, JTWC best tracks for 2005 were not available):


quiescent days____quiescent period

31________________Apr 16, 84 to May 16, 84
30________________Apr 20, 85 to May 19, 85
21________________Apr 17, 88 to May 07, 88
18________________Apr 16, 04 to May 03, 04
17________________May 12, 75 to May 28, 75
17________________Apr 27, 78 to May 13, 78
16________________Mar 25, 90 to Apr 09, 90
15________________Jan 10, 04 to Jan 24, 04
14________________Apr 24, 72 to May 07, 72
13________________Apr 01, 74 to Apr 13, 74
12________________Dec 25, 74 to Jan 05, 75
12________________Apr 15, 65 to Apr 26, 65
12________________May 01, 69 to May 12, 69
12________________May 18, 78 to May 29, 78
12________________Dec 01, 78 to Dec 12, 78
12________________Dec 25, 85 to Jan 05, 86
12________________Dec 28, 90 to Jan 08, 91
12________________May 03, 92 to May 14, 92
11________________May 21, 92 to May 31, 92
11________________May 04, 99 to May 14, 99
11________________Jun 02, 78 to Jun 12, 78
11________________Nov 29, 69 to Dec 09, 69
11________________Mar 14, 76 to Mar 24, 76
10________________Jun 08, 75 to Jun 17, 75
10________________Mar 24, 84 to Apr 02, 84
10________________Jun 21, 69 to Jun 30, 69
10________________Oct 26, 65 to Nov 04, 65
10________________May 13, 72 to May 22, 72
10________________Mar 30, 97 to Apr 08, 97

quiescent days / num_of_occurances

31_____________1
30_____________1
21_____________1
18_____________1
17_____________2
16_____________1
15_____________1
14_____________1
13_____________1
12_____________8
11_____________5
10_____________6
_9_____________3
_8_____________9
_7_____________8
_6____________11
_5____________23
_4____________13
_3____________21
_2____________28
_1____________32

 

[Margie Kieper]

And speaking of the remote possibility of subtropical storms...has anyone been watching the frontal low that rounded the tip of Africa into the SWIO over the weekend? Even though yesterday evening the NRL tropics rain accumulation still showed the most precip associated with the frontal boundary, that has changed in the past 3-6 hours, with most of the precip surrounding the low, as it has slowly developed some convection over the past day and a half. Quikscat from last night shows a couple of 35-kt vectors in the well-defined surface low. Even though it's just going to slide east and very shortly move into cooler waters, it's interesting to watch.

Tuesday update: the South African Weather Service noted 10m waves associated with this cutoff low...and aided by the spring equinox and a new moon, it resulted in flooding at Durban (hat tip to S2K).

SSD labeled it a subtropical storm.