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Short range model discussion - into 2018


Paul

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Posted
  • Location: Camborne
  • Location: Camborne

In a relatively quiet period the outlook still has a marked N/S bias with much of the frontal activity confined to the north. The NH profile and surface analysis at midnight.

gfs_z500a_nh_1.thumb.png.59cb9d632d30ef1ec456c0779bebce2f.pnggfs_uv250_nh_1.thumb.png.f0561f151bf25727b0d6922e94a9a43d.pngPPVA89.thumb.gif.41760f6e14d0640142da78baea08e3e9.gif

A pretty clear night over much of England and Wales resulting in quite a cool start to the day

2018_9_13_300_MSG4_26_S1_grid.thumb.jpeg.216783dd0a72a755ef9a71cbd6972aea.jpeg

and this will lead on to a sunny day with the odd shower popping up in places. But further north the low to the north west of Scotland will drift north east whilst the associated front and patchy rain south across southern Scotland and northern England, dissipating en route, leaving showers in it's wake. Quite windy here as well. Later in the day a wave forming on the trailing front will bring more persistent rain to N. Ireland and western Scotland which will drift south east into northern England during the evening. Temps generally around average or a tad below.

PPVE89.thumb.gif.9fb2fdff825cffe6401567dfc60da6ba.gifgfs_t2max_c_uk2_4.thumb.png.577656141ad568dc39144ea65e615ae8.pngp08.thumb.png.d08bd2b1b637dc15ac252774d90bf68b.png

p12.thumb.png.b4b425c991fc126c05d9b15f4812a8e5.pngp17.thumb.png.cb129d3599f5211f779131439dc04134.pngp21.thumb.png.2857af127a6c44f1bad28f12688e2f3e.png

This is more or less the scenario overnight and through Friday as waves on the fronts bring patchy/showery rain into Scotland and N. Ireland moving south Into northern England, Wales and the north Midlands whilst south of here remains dry and quite sunny, albeit not that warm.

PPVG89.thumb.gif.68242eb588d314a91af72b232eccf648.gifPPVI89.thumb.gif.da997cdb036e238325b822576125384b.gifgfs_t2max_c_uk2_8.thumb.png.4dfa60f48f598eb793a4a94d14382b7d.png

r04.thumb.png.4b7da4261acbe2ed6b0b15068e0a0a73.pngr07.thumb.png.096537b35d398d056d166f19fbf4513d.pngr11.thumb.png.46ac5c26e1967442c32dab18790834ba.png

r14.thumb.png.0a9a3ce983a2142e54b63a2bdee8d9a9.pngr18.thumb.png.134d480424d0e84c228e581ae5bb08b9.png

Saturday is a mainly dry day but with the front straddling the country quite cloudy in northern areas but the is a lot going on to the west with major troughs being ejected east from the vortex over N. Canada

gfs_z500_vort_natl_12.thumb.png.e60fbe53c496f677335310e7fe68aedd.png

and by mid afternoon rain and strengthening winds are effecting N. Ireland and western Scotland and will track east and south effecting all areas north of the Midlands by midnight Sunday with once again the south remaining dry.

PPVK89.thumb.gif.f3c422536891a4cbe841a37059193f41.gifgfs_t2max_c_uk2_12.thumb.png.3906ea0eeacf3111f066ba9acb16b875.png

gfs_ptype_slp_uk2_12.thumb.png.5469b07f961d2acca0bde959a86c7054.pnggfs_ptype_slp_uk2_13.thumb.png.05c952d47c0d7f1887b03fc756d4b869.png

By Sunday the system has tracked east into the North Sea leaving the associated fronts straddling the country with the rain belt slightly further south and blustery showers in the north, but the south east still dry and somewhat warmer.

PPVM89.thumb.gif.d38558734cc2ba3a4b52a09b52910a2d.gifgfs_ptype_slp_uk2_16.thumb.png.809cfef842fbb082bc258928150948b6.pnggfs_t2max_c_uk2_16.thumb.png.749c7c582f235ca549c81428dc9e61ee.png

On Monday there will be some cloud around but generally dry and warmer over England and Wales

PPVO89.thumb.gif.d4f0b15ea41c2b06214834f78a184926.gifgfs_t2max_c_uk2_20.thumb.png.89b8fd62ec51b00cdd65571db8f331af.png

And the NH profile at T120 and Helene in close attendance to southern Ireland.

gfs_z500a_nh_21.thumb.png.df1dc20102c2030a9149e192b6520105.pnggfs_uv250_nh_21.thumb.png.177250a88bc89ff47b82783cc30c3987.pnggfs_z500_vort_natl_21.thumb.png.6c54e108a32439dd9d4260a0d79c6270.png

 

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

The track, speed of travel and intensity of Helene a long way from being nailed with major differences between the gfs and ecm. The latter has it slower, less intense and more on a north east track as it appears to separate from the jet. The ecm at T120

120v.thumb.png.2903c3efe57f2cf0332cc52c8a565bcf.png120j.thumb.png.7e946953a74f5146ba122c9245f46442.png

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

The south Irish Sea/west Wales is the favoured track for Helene with this evening's ecm which could give severe gales for a time in the south west and gales across south Wales and the Midlands with the Atlantic dominated by the upper trough.But there is bags of time for adjustments to be made.

96v.png120v.thumb.png.e1bf38166d217241d08310748989ff83.png500.thumb.png.3730c057043f910d61e46edc1a2521e5.png

161256454_500j.thumb.png.0c9a4dc8ccdea0b7db11c46368be30b1.png

 

 

 

Edited by knocker
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On 13/09/2018 at 06:15, knocker said:

Saturday is a mainly dry day but with the front straddling the country quite cloudy in northern areas but the is a lot going on to the west with major troughs being ejected east from the vortex over N. Canada

gfs_z500_vort_natl_12.thumb.png.e60fbe53c496f677335310e7fe68aedd.png

and by mid afternoon rain and strengthening winds are effecting N. Ireland and western Scotland and will track east and south effecting all areas north of the Midlands by midnight Sunday with once again the south remaining dry.

PPVK89.thumb.gif.f3c422536891a4cbe841a37059193f41.gifgfs_t2max_c_uk2_12.thumb.png.3906ea0eeacf3111f066ba9acb16b875.png

gfs_ptype_slp_uk2_12.thumb.png.5469b07f961d2acca0bde959a86c7054.pnggfs_ptype_slp_uk2_13.thumb.png.05c952d47c0d7f1887b03fc756d4b869.png

By Sunday the system has tracked east into the North Sea leaving the associated fronts straddling the country with the rain belt slightly further south and blustery showers in the north, but the south east still dry and somewhat warmer.

As interesting as how Helene itself progresses, this feature appears that it may be an example of downstream cyclogenesis excited by Helene.

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Posted
  • Location: SE London
  • Location: SE London

Ex-Helene:

Good consistency from global models with ex-Helene tracking NNE over Ireland into the Iceland gap as a deepening system. This is consistent with the limited climatology for these types of transition in the NE Atlantic - Debbie(1961), Gordon (2006) and Ophelia (2017). Nb that all three of these systems produced damaging winds over Ireland/W/NW UK.

08L_tracks_2018091500z.thumb.png.99577467b3b33d050cc14963783b3b97.png 08L_gefs_2018091500z.thumb.png.efdc0cad408235fbf88651b8b124c57b.png2018091800_t072.thumb.gif.df683bef6f6130274eb0c69bdf634c96.gif

Study of the  three previous storms suggests that transition produced a hybrid Shapiro-Keyser like structure similar to transitions in zonal flows and somewhat similar to wintertime rapid deepeners. However, this may not be reflected in Met Office analyses  (ASXX) and in measures of rapid deepening (Sanders&Gyakum 'bomb' criterion). The hybrid structure typically consists of a deep warm core ('warm seclusion') around which exrtratropical-like conveyor belt features form. Analysis of simulations and satellite imagery ( Gordon & Ophelia) for the cases suggests they all produced sting jets soon after transition. By the time of 'landfall' over Ireland  the surface wind field in the frontal fracture region was dominated by the cold conveyor belt jet with SJ(s) in close proximity above. A  possible exception was Debbie where a SJ may have been reaching the surface directly in western Ireland. Typically this scenario produces extreme and damaging wind gusts over land. 

 

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Posted
  • Location: Crymych, Pembrokeshire. 150m asl
  • Weather Preferences: Extremes of all kinds...
  • Location: Crymych, Pembrokeshire. 150m asl

Maximum winds gusts over the next 48 hours as predicted by three short term models:

WRF          image.thumb.png.71b0e01221c9d7c4731f46c1b20194e1.png    

ARPEGE   image.thumb.png.0b0ec1928102687f6cc0c138c37a2d20.png

ICON         image.thumb.png.e6f2bfb1a476b5b287fdce2104d3e1c1.png

Plus wind gusts expected at around 2300 hrs tomorrow by the GFS 0.25:

image.thumb.gif.c3e8872be4759e61f1fcf94f3fe6e4f5.gif

So, maybe 100kph/65kph gusts in western coastal areas between 2200 Monday and 0500 Tuesday before the storm moves away to the north east and weakens.  Not particularly severe but still may be disruptive especially to Irish Sea ferries and people living by the coast.  I would very much like to see one of Knockers detailed summaries of the next 48 hours......

Edited by Sky Full
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Posted
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.

NetW-wx take on gusts.

1962037978_Knockersthread.thumb.png.11625544aa85bf440ee6b62e1de6dc88.pngknockers.thumb.png.e59c934610fa7d89bd84b60e65a31ba6.png1723512428_knockersmod.thumb.png.c778fd334340b684779df712f37d38f1.png

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Posted
  • Location: Camborne
  • Location: Camborne

Putting aside for the moment TS Helene the rest of the week looks likely to be dominated by the major atlantic trough with depressions forming along the airmass boundary and tracking quickly north east on the very strong upper winds. Thus quite likely on Wednesday wet weather and very strong winds, including severe gales, will effect norther regions for a time. Quickly followed by late Thursday by the arrival of the next depression which could bring very strong winds to most of the UK but particularly western and northern regions.

gfs_z500a_nh_9.thumb.png.2fe279cfb3a166579de3d7f214e80af4.pnggfs_uv250_nh_9.thumb.png.d0d58fa09ebad26bfdf9b41a63c039ee.pnggfs_t850a_nh_9.thumb.png.6f6dc77208c89f9000b0142ade37ade7.png

gfs_z500_vort_natl_13.thumb.png.8d16f7ca540e6b418b6c9f85f0df5bed.pnggfs_ptype_slp_eur2_13.thumb.png.b1aa36527b8c82c45221344df77189ce.png

gfs_z500_vort_natl_18.thumb.png.265b8faee59440484bc2acbdc3458cad.pnggfs_ptype_slp_eur2_18.thumb.png.22fe6906250bf6415fcf0e4754cdb425.pnggfs_ptype_slp_eur2_20.thumb.png.7dcbc18ab1c085f3086e1d6e2bc9da92.png

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Posted
  • Location: Camborne
  • Location: Camborne

The outlook for the week is unsettled with periods of rain and strong winds with the caveat that the east/south east will not be so adversely effected as the the north west/west and may even have the odd warm and quite pleasant day as warm air is advected from the south.

The NH profile and surface analysis at midnight

gfs_z500a_nh_1.thumb.png.2e20999b4130720e28878d0c05f3bd77.pnggfs_uv250_nh_1.thumb.png.5419852d657f8a17a84f15278930c46e.pngPPVA89.thumb.gif.0b6a5c7eb95282f619e9cfce65e5772d.gif

So a fairly quiet start to the day with some cloud lingering in the south from the weakening front and cloudy over northern Scotland with the odd shower around.But a wave on the front tracking NNE, prior to the arrival of ex tropical storm Helene, will bring some light rain to north Wales, north west England, N. Ireland and western Scotland by late morning and the afternoon. Meanwhile it has been quite a warm day over much of England and Wales

PPVE89.thumb.gif.19ecd06e330aa9d2bfa0875cf53803ef.gifgfs_t2max_c_uk2_4.thumb.png.213877c434c68c13f613a7b779ae92b5.png

p11.thumb.png.5e4f085a7e163b62cf2cce189b412ed6.pngp14.thumb.png.412fbd8d5219efcecc46c9d6699ab79d.pngp18.thumb.png.c7e7eaa591ef0ea05f4d75ed9d69478f.png

During the evening Helene arrives over Ireland en route to clear northern Scotland by midday Tuesday and with it some heavier rain, mainly effecting north Wales, North west England, N, Ireland and Scotland and with it some strong winds which will mainly impact the south west, Wales, central and north west England, These don't appear to be quite as bad as once feared.

PPVG89.thumb.gif.c7b20211e084201186b9cd5369f2034a.gifPPVI89.thumb.gif.cd70f43180c9dd80255a13f1a5ccc9aa.gifgfs_t2max_c_uk2_8.thumb.png.6c4aeaed990f191c587ced9b0d4cbc29.png

r21.thumb.png.3af6095f8db545b1a6607759c9dd7899.pngr00.thumb.png.1856f32a56d861de0c891d1872bc0cb2.pngr06.thumb.png.7916b27bc59b83a9125a73f5999f4d47.png

r10.thumb.png.198c8a89b2434c2ff32aacf656e244c3.pngg00.thumb.png.86cd95f1866eb782d8c4d12239c6382c.pngg04.thumb.png.5bd0da9543874b1f3a398307fd1e4d3c.png

g11.thumb.png.42439db9b215aa4651eed3ebcee89b4d.pngtotalprecip_d02_48.thumb.png.bf4015d50e7d8afea081a55be2920ddd.png

But there is little respite for the north west as by 1200 Wednesday the next intense low has tracked north east on the strong upper jet and has brought more strong winds and rain to N. Ireland and Scotland and the later to the rest of the country as the associated front moves east.

PPVK89.thumb.gif.069fa765955ecc20896e429d01d8f54c.gifgfs_uv500_natl_11.thumb.png.e847eae00e2e6c68518e17e469d8d248.png

gfs_ptype_slp_uk2_12.thumb.png.c04152f692e91d461ac15f0e49e010d9.pnggfs_t2max_c_uk2_12.thumb.png.2b219573863c4807967e029cf8a25fa8.png

I have a problem over Thursday and Friday because of the massive difference between last evening's fax charts and the gfs as the latter again makes much more of the developing wave, so much so that it has the low 968mb in the North Sea by 0600 Friday. It did the same last evening, Yesterday's ecm, although not agreeing with the gfs solution; was certainly more active than is being suggested by the fax. I've no reason to think the fax charts are wrong so will go along with their analysis but await this morning's ecm with some interest

Suffice it to say it will be wet in many areas on Thursday and quite windy and drier and less so on Friday.

PPVM89.thumb.gif.7b074b18792be5671b05a2af83ce700d.gifgfs_ptype_slp_eur3_15.thumb.png.446341bb7f567387c352d08db8807fad.png

PPVO89.thumb.gif.ab34f330e532c7c9328362551d14eee0.gifgfs_ptype_slp_eur3_19.thumb.png.a74ae2039dd159eeb4e53834f67ec8c1.png

 

 

 

Edited by knocker
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Posted
  • Location: Camborne
  • Location: Camborne

Further to the above this morning's fax and ecm are in good agreement at 1200 Thursday with front becoming somewhat energized without forming a deep low so confirmation of a wet day as the front tracks south east. Prior to that confirmation of a wet and windy day up north on Wednesday.

PPVL89.thumb.gif.ff123504a802758e3ec92562657830a5.gifa84.thumb.png.c2fe0733fbae4fb538df987846a71be5.png

PPVJ89.thumb.gif.98866ceee7526e8eb04bc1c83a803480.gift60.thumb.png.2e0b3181b1f8a82f3b5964d5b3b19fb3.pngg66.thumb.png.e2be83ed3129e33c8a2805d19b489a97.png

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Posted
  • Location: Camborne
  • Location: Camborne

This evening the rain will persist for a time in the north west, probably not clearing until the early hours . Further south as Helene into south east Ireland the wind will veer and increase in the south west and as it tracks NNE the stronger winds in the southern Quadrant will move with it.to effect Wales and central England, but particularly western coasts. The associated rain will mtove through Wales, northern England and Scotland, clearing there by late morning.

PPVA89.thumb.gif.69f5891896e4f0e20ce6776062d7f371.gifoverview_009.thumb.jpg.20c2920c15702979f1ffaee597a7cbe9.jpgoverview_012.thumb.jpg.f1a301b0f229773980573afe155781d8.jpg

overview_015.thumb.jpg.66ad6182695be44336f9be16c6752a6e.jpgoverview_018.thumb.jpg.8e05f2d9697b92e0e36bd04fecb32e57.jpgoverview_021.thumb.jpg.94028542d588251b4bb1916af5b328a2.jpg

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Posted
  • Location: Camborne
  • Location: Camborne

The gfs is still going for the rapid deepening of the wave on Thursday that no one else is picking up unless the ecm does so this evening. It surely must have something to do with the left exit of the very strong jet.

gfs_ptype_slp_eur3_14.thumb.png.90694c47f5d7a0dbfcefa693bf2f5996.pnggfs_z500a_natl_14.thumb.png.b7fc35bc59052a86b6ee00ef34ca2d8e.pnggfs_uv250_natl_14.thumb.png.dbb1277b766a564829d3865c36066e9a.png

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Posted
  • Location: Camborne
  • Location: Camborne

The outlook can be summed up with one word - unsettled but perhaps worth reiterating the NW/SE bias.

The 500mb chart and surface analysis at midnight

eur_full_500.thumb.gif.05777246438d8d84e36df3dbc4cd9a56.gifPPVA89.thumb.gif.dde978133b66403b482c195a1f7e758d.gif

The remnants of Helene are currently tracking up the east coast of Ireland, the position at 0300. (Worth noting the very warm temps in the south westery flow)

03.thumb.gif.a7fd7b536cce37addcd73f90f6f9e792.gif

and thus the strong winds in the southern quadrant will move north over Wales, the Midlands and northern England during the day. The main rain belt will quickly traverse northern England and Scotland this morning clearing by early afternoon but there is little respite as the cold front associated with a deep depression north west of Ireland will bring more rain into western parts by early evening. Despite all this still quite warm over England and Wales

PPVE89.thumb.gif.2d2fa9c1f97c66b825cbfb6f2bba92b3.gifgfs_t2max_c_uk2_4.thumb.png.c404c10a40cda29d82ffa0aaae9386d6.pngg09.thumb.png.e49bfdf966255aefa66bcf3593e1c6fa.png

g12.thumb.png.d123f4b2c6bb95b96e9420121c424d10.pngg16.thumb.png.2e7601f404f73e268c1a555a571ec833.pngp09.thumb.png.cced78ba7fd53a82f0aef3fd6b36d443.png

p12.thumb.png.ea270e2af664d92144048ceca7bb3072.pngp15.thumb.png.23a57243dfdf19c31ba4f1ce6ea476f1.pngp18.thumb.png.019cda85423a62d1247de6b88fe69887.png

The front and rain clears all areas north of a line Plymouth - the Wash by midnight but another  intense system is forming in the southern quadrant of the upper trough away to the south west and this tracks very quickly NNE overnight and through Wednesday morning to be 977mb over Scotland by midday. This will bring heavy rain and strong winds to N. Ireland and Scotland through Wednesday and a line of rain will move south east on the associated cold front.which is the boundary between the cooler and warmer air.

PPVG89.thumb.gif.88812dc7b9ccf2175f292fbc6df19f16.gifPPVI89.thumb.gif.58d8e32b8583e0f4ec49bfe3b08a2c44.gifgfs_t2max_c_uk2_8.thumb.png.0524d05b714dbc095698f043c2b35a72.png

r21.thumb.png.a58eb7b3a7849a143f197fb5e6f5833e.pngr06.thumb.png.6a041f2582924d7e43f77174e1db22cb.pngr09.thumb.png.7bf046006259b5156780c8fadb603be5.png

r12.thumb.png.d0c1f69b3168e5ecd5c4fb36ff1ae2fc.pngr15.thumb.png.b9049fceeea35301408ff1dda6ac92ff.pngw10.thumb.png.84e3becc8e731eaf306aff996d58ff2b.png

w14.thumb.png.58f8c4b0e7fe3955684350b5a984daa4.png

Overnight continuing windy with squally showers in Scotland but further complications ensue further south as a wave forms on the trailing front (This was causing some problems yesterday) which brings rain the N. Ireland and much of England and Wales as it traverses the country through Thursday with the front still marking the divide

PPVJ89.thumb.gif.f1c79a2dc0675ef00300286396ddd57d.gifPPVK89.thumb.gif.c676589d78848618512d384c706cbfb0.gif

gfs_ptype_slp_uk2_12.thumb.png.7d05e5a7c57f75e537ad5255043985fb.pnggfs_t2max_c_uk2_12.thumb.png.6afef4a4129fd2fe22f9736e2301d835.png

By Friday the wave has deepened and is over southern Norway leaving the UK in a blustery north westerly with sunny intervals and showers and quite a cool day

PPVM89.thumb.gif.3a375e684885d2bc11999150056d713c.gifgfs_t2max_c_uk2_16.thumb.png.62d3084b008dd2e24c17f3beb2d9f859.png

A much better day on Saturday to start with with some transient ridging but another system is getting organized on the trailing front away to the south west and rain from the associated front will arrive over western regions during the afternoon.

PPVO89.thumb.gif.af3c5bcc73879aa195a8b8798ce342b7.gifgfs_ptype_slp_uk2_20.thumb.png.148a61963f8a4ddfcc0f172f55d87557.pnggfs_t2max_c_uk2_20.thumb.png.258151025193181d3bd1b20f6489132c.png

And after that rather complicated synopsis (apologies for that) the NH profile at T120

gfs_z500a_nh_21.thumb.png.9195d2935a1d5da458fffe9a3e912e16.pnggfs_uv250_nh_21.thumb.png.66434d075c22949185fcda9fd71502c8.png

 

Edited by knocker
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