Strange METAR or TAF / METAR or TAF interpretation

the first "BECMG" with that "NSW" does not extend all the way to the end of the TAF - as Peter writes - but is later replaced by " BECMG 2707/2710 10010KT " and in that period lies the RA. So the rain does not happen in the NSW-period.

I thought NSW trumps the FEW035. Clearly not.

Nope. The W (Weather) refers to stuff like rain, snow, fog, hail etc.

WMO Manual on Codes. METAR is form 15, TAF is form 51.

The change groups TTTTT GGGeGe in the form of BECMG GGGeGe shall indicate a change to forecast meteorological conditions expected to occur at either a regular or irregular rate at an unspeci?ed time within the period GG to GeGe. The duration of the period GG to GeGe shall normally not exceed two hours and in any case shall not exceed four hours. The change groups shall be followed by a description of all the elements for which a change is forecast. When an element is not described in data groups which follow the change groups, the description of this element for the period between G1G1 and G2G2 shall be considered to remain valid subject to Regulation 51.1.5. The "elements" are the wind, the weather, the vis and the cloud.

So

EGKK 260502Z 2606/2712 VRB03KT 3000 BR FEW035 
PROB30 2606/2607 0600 FG BKN001 
BECMG 2607/2610 9999 NSW 
PROB30 2700/2707 5000 BR 
BECMG 2707/2710 10010KT 
TEMPO 2709/2712 7000 RA

is equivalent to

EGKK 260502Z 2606/2712 VRB03KT 3000 BR FEW035 
PROB30 2606/2607 VRB03KT 0600 FG BKN001 
BECMG 2607/2610 VRB03KT 9999 NSW FEW035
PROB30 2700/2707 VRB03KT 5000 BR FEW035
BECMG 2707/2710 10010KT 9999 NSW FEW035
TEMPO 2709/2712 10010KT 7000 RA FEW035

Peter the use of NSW is defined by ICAO Annex 3 which you can see here Clickey here

Hope that helps. Colm

Many thanks all. I never realised NSW is really a terminator expression for preceeding specific types of wx.

Learn something every day

Look at this development:

METAR LDZA 291300Z 21014KT 150V240 CAVOK 38/09 Q1011 NOSIG
METAR LDZA 291330Z 21014KT 170V250 CAVOK 37/12 Q1011 NOSIG
METAR LDZA 291400Z 21016KT 170V260 CAVOK 37/12 Q1011 NOSIG
METAR LDZA 291430Z 22015KT 180V250 CAVOK 36/12 Q1011 NOSIG
METAR LDZA 291500Z 24017KT CAVOK 36/13 Q1011 NOSIG
METAR LDZA 291530Z 23018KT 200V260 CAVOK 35/13 Q1012 NOSIG

It seems that nobody forcasted so violent winds:

METAR 291630Z 30030G46KT 250V330 9999 DS NSC 28/12 Q1014 BECMG TL1730 27010KT

And TAF ammended appropriately:

TAF AMD 291631Z 2916/3012 30030G45KT CAVOK TX29/2917Z TN23/3006Z BECMG 2916/2918KT 27010KT BECMG 2918/2920 27005KT PROB30 TEMPO 2920/2924 VRB20KT 4000 TSRA SCT040CB SCT040 BECMG 3004/3006 02010KT

Yes; you can have unlimited wind speed with "CAVOK".

It seems that nobody forcasted so violent winds:

Well, not "nobody". I guess this was the on-airfield forecaster:

METAR LDZA 291600Z 24013KT 200V260 CAVOK 35/14 Q1012 TEMPO 28030G40KT=

I never realised NSW is really a terminator expression

Sometimes also abbreviated to HLVB

(Hasta la vista baby....)