Jack Wales

SST's are generally around 28-29C with very low shear forecast for the next few days. pressures are falling over the area and very cold cloud tops were obseved yesterday as per SB's post. All the ingredients are there for a potentially powerful system. The only blocker at the moment is the apparently weak circulation with no discernalbe LLC. However the latest satellite images appear to show convection becoming more concentrated to a smaller area east of the Yucatan peninsular combined with early signs of an outflow beginning to establish. If the rotation can tighten, this system shouldn't waste any time to get going!!

Chris has certainly been an interesting one, I'm sure that NHC reanalysis will make Chris a hurricane about 12 - 24 earlier than they did. It's bizarre how a hurricane formed over 21-22C waters although I suspect the thermo-dynamic structure of the system must have played a part. It just goes to show that it is not beyond the realms of possibility for a hurricane / tropical storm to reach our shores!!

Well, it's allegedly mid-summers day however in these parts it's poured with rain continuously, the lights have been on all day and the temperature has not gone above 13C. It could well be December!!

Can whoever starts the CET threads please state the averages in future? July's averages are: 1971-2000 average: 16.5C 1981-2010 average: 16.7C July's extremes are: 2006 : 19.7C 1816: 13.4C

Chris is looking more like a hurricane now with convection wrapped right around the centre and a distinct eye feature clearly visible.

No, it's going to become extra-tropical in a day or so and briefly meander around in weak streering currents before being abosrbed by another Atlantic low. That low will then be picked up by the jet and move streadily north east. Fair play, Chris is a beautiful looking TS though,,,

95L is starting to take shape now which is surprising given it's at 38 degrees north over 22C SST's. Look at the convection forming over the centre and the banding features now starting to take shape. IMO this could be upgraded to a subtropical storm at the next advisory.

Yes, that's an interesting forecast, especially as TWO are one of the better ones out there. Does anyone know when the NW summer forecast will be avaialble?

Beryl now up to 70mph according to the NHC, the sat images appear to show a ragged eye-like feature developing. Beryl is very near to landfall now though so it's touch and go whether she will attain hurricane strength.

I can't help but think GFS are underplaying those values, I think we'll almost certainly get into the 12's now.

GFS seems to be underplaying the 2m temps as it often does during warm spells. It is quite conceivable that the CET zone could average 15C - 16C for the rest of the month which would probably uplift it to at least 11.5C after roundings.

Great to see the hurricane season off to such an early start, so much so that I missed the 93L invest!! Although Alberto is now down to 40 knots the symmetrical shape of the system would appear to indicate a fairly low-shear environment although falling SST's on the projected track could inhibit any significant strenghthening

I believe that synoptically, summer starts to show it's hand towards the end of May and that it's possible the forthcoming weather pattern could become 'locked in' however I do feel that 6-8 weeks may be somewhat optimisitic. Interestingly I don't see any standout teleconnections which could drive this summer so as the wavelenghths expand it could be that our summer is front and back loaded i.e. pleasant June, poor July / August and possibly a warm September.

Significant insrease in temperature over the next week or so. This could add at least 2C to the final outturn.

I agree with Robbie Garrett as the signals for this summer are most unfavourable for settled and warm synoptics. This is not negativity but sound forecasting underpinned by the current and projected teleconnections. Despite the current ENSO neutral state, the northern hemisphere atmospheric profile remains reflective of the embedded ENSO –‘ve pattern which has plagued us over recent summers. In our neck of the woods this is reflected in the mid atlantic ridging and the NW to SE jet flow currently being forecast. To me summer is already shaping up to be another wash out as I believe the transition to weak El Nino will arrive to late to break the current atmospheric base state, at best I believe we will have a settled end to August and a possible Indian summer. As for the rest of summer, any hopes of a late shift towards a more average / settled conditions will rest with the Pacific and a possible increase in angular momentum. If (and it’s a big if) this can shift the MJO into phase 7/8, this could teleconnect to a negative AO which in turn will help switch the atlantic jet into a more SW to NE flow, well to the north of the UK. Interestingly, this pattern would also be supported by the current Atlantic SST profile (which is very different to 2011)……however I believe this is a long shot. Finally, although seasonal forecasting remains very much an emerging science, I think it is wrong to dismiss the signals simply because they do not show what we want. In my limited experience I don’t believe we will see a return to more settled summers until a sustained El Nino pattern is re-established. I’m beginning to realise that during the period 1989 to 2006 we were spoilt with several good summers, it seems that many seem to expect sustained warm/dry spells in Jun-Aug when realistically we may not see 1995, 2003 or 2006 type summers again for another 50 years. Admittedly I know little about long term weather cycles but it does seem that we have shifted into a different phase since 2006, not just for summer but all seasons.

I think the trough currently sat on top of the UK will continue to migrate westwards into atlantic with hights building over Scandi... normally a recipie for warmth (albeit without a southerly tracking jet!!). I'm going to stick my neck out as I believe there could be a significant warm spell. Therefore my estimate is 12.7°C

Thanks GP, an interesting read as always. The models are already focusing on greater heights over scandi in FI, with scope for cut-off lows to develop to our SW. There certainly appears the possibility of tapping into a much warmer airflow from the SE however the potential proximity of the aforementioned lows could prove to be a bit of a spoiler. It will be interesting to see if we observe a change in the Nina base state during summer, as I see it that is key from mid June onwards. Incidentally, what (if any) bearing will the Atlantic SST's have going forward? I don't see much pattern (yet) to support strong heights over the azores region.

Agreed although CFS do have a six month forecast... http://www.cpc.ncep.noaa.gov/products/people/wwang/cfs_fcst/images2/euT2mMon.gif http://www.cpc.ncep.noaa.gov/products/people/wwang/cfs_fcst/images2/euPrecMon.gif Although these can be way off, they do provide an idea of the trends they have in mind. For me the transition from La Nina could be a driver this year, will the change be enough to shift the atmospheric base state in time for June?... Current... http://weather.unisys.com/surface/sst_anom.gif Projected... http://www.cpc.ncep.noaa.gov/products/people/wwang/cfs_fcst/images2/nino34SSTSea.gif The current forecast is for ENSO neutral or maybe weak El nino synoptics by late May. This could result in summer synoptics being more heavily influenced by other factors and teleconnections such as Atlantic SST's and MJO activity to name a couple. May will be a key month as IMO this is when summer starts to show it's hand.

Tricky one. I expected March to come in below average and look what happended. Anyway, strong signs for ridging over the mid atlantic so although I don't think the northerlies will be as potent as some of the models are suggesting, it looks like a cooler pattern is about to displace the current one. Although I'm tempted to go lower I'll opt for a slightly below average 8.1°C

Interesting thoughts SB, the models were all going for another La-nina summer but the apparent dissapation of ENSO -ve anomolies in the pacific seem to have taken them all by surprise. If you look at the current SST profile, I'd say that only the Nino4 region is still enso -ve with the other regions either displaying neutral or even +ve anomolies in region1/2... The live daily chart seems to continue the trend... http://weather.unisys.com/surface/sfc_daily.php?plot=ssa&inv=0&t=cur&expanddiv=hide_bar Which also seems to be well supported by the sub surface pattern (notice from the time lapse the rapid swing from of -'ve to +'ve anaomolies)... http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/wkxzteq.shtml As you say it would be unusual to see an El Nino in tandem with an e'ly QBO but the current pattern shift at least gives me some hope that all may not be lost for this summer :-)

20C - Early June 25C - End of August 30C - Unlikely

The competition is to see who can guess the closest to the CET on a month by month basis, I think there is a sperate thread for the annual cet.

Recent scrubbing of upper level westerlies coupled with the drop in total angular momentum indicate a shift from the current synoptics. Certainly scope for some incursions from the east but as cold pooling over the continent will be much moderated by now I'll go for 5.9°C.

In order to achieve a CETof 4C, the final two weeks need to average a CET of 7.6C. That's a tall order, especially given the potential northerly progged for the weekend and inversion type cold from hp over southern UK thereafter. After adjustments I believe we will end up in the low 3's

It's looking exceedingly likely that February will finsh up with a CET of <2.5C. With more support for the northerly into next week, the CET could be around zero at the months half way stage. If so, even if the final two weeks finish with a +5C CET, this will still deliver a final CET of around 2.5C. None of the models are showing a return to a sustained mild spell with most opting for HP inversion type cold, a cool NW'ly flow or even a reset of the easterly. I would guess the first two being the most likely outcome with a final CET of around 1.5C - 2.0C