jamie wrote:
I see Paul is on the desk today....the latest thunderstorm outlook includes afternoon and it's wild!!!!!! Paul if your reading this and have the time, what are your personal thoughts on today's setup. Would you have a top spot to be at?
Yup rather a crazy outlook!
Issued at: 9:13am Friday 8 Jan 2016
A front is expected to move across central and northern New Zealand today,bringing a period of significant weather. For more information see the latest SEVERE WEATHER WARNING and WATCH at http://metservice.com/warnings/home.
Thunderstorms are expected with the front and some of these thunderstorms could be SEVERE. From Northland down to Taranaki, and across to the Bay of Plenty and the central North Island high country, there is a high risk of thunderstorms bringing heavy rain with intensities of 15 to 25mm/hr and strong wind gusts of 90km/hr. Additionally there is moderate risk of SEVERE THUNDERSTORMS which could result in downpours of 25 to 45mm/hr in localised areas and strong wind gusts of 90 t0 100km/hr and possibly stronger. The risk of thunderstorms should diminish from Waitomo to Taranaki late afternoon, and from remaining northern and eastern areas in the evening or at night.
In the southwest of the North Island and the far nort of the South Island, there is a moderate risk of thunderstorms this morning and afternoon, bringing heavy rain with intensities of 10 to 25mm/hr.
One or two thunderstorms are also possible during the period in the east from Gisborne to Wairarapa, and this morning about Nelson, Buller and northern Westland.
Elsewhere, no risk of thunderstorms or significant convection expected.
12Z GFS run quite crazy as well with LI values down to -6, right through my trip back into the tron this arvo!
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I see Paul is on the desk today....the latest thunderstorm outlook includes afternoon and it's wild!!!!!! Paul if your reading this and have the time, what are your personal thoughts on today's setup. Would you have a top spot to be at?
No, I'm not on today. I was working last evening. One of the things that struck me, along with the absolutely unstable atmosphere, was the strength and depth of the ascent through the whole depth of the atmosphere - supported as someone mentioned earlier by strong divergence in the upper atmosphere. The last time I recall a similar setup was during the Mangetepopo very heavy rain event where localised downpours up to 50mm/hr occurred and you will recall 7 students and a teacher died caughtby a flash flood in that river.
I will be watching what happens from home today!
Steady heavy rain here in Glenfield - 5.1mm in the last hour. Temp is 20.1 and dewpoint 17.6. Cloud cover is solid, so hard to see what's going on up there. My sister is taking my son to Star Wars up at Albany this afternoon. I told her to take a torch in case the power goes out.
Pleasantly sunny in Glenfield now - enough to dry out the roads but it's made it feel very humid in the process. Had 39.8mm of rain in my gauge since midnight. Temp now up to 23.8 and dewpoint to 20.9.
Only 57 strikes picked up by Grey Lynn weather station which is very weak for elevated storms. Weak instability.
I think these warm advective thunderstorm set ups have a higher bust rate than the cold advection. When you have 15c at 850mb, its a big obstacle to parcels lifting from the surface when there is no daytime heating.
Models had clearance occurring much earlier, so that line that developed around 6PM would been much more beefier if it occurred around prime DTSH. Temps did not go above 22°C during the afternoon due to cloud cover, models predicted temps up to 24-25°C which would have been the perfect temp for the parcel to rise and give subsequent latent heat release.
I agree with you Steve, Warm advection is allot more risky as the instability is either full on or off. The Lightning that occurred yesterday was mostly all elevated.
A shame the setup turned into a complete flop, but the difference was just in timing...... models had pegged for a bit earlier while in reality it was around 3 hours too late.
