Nick F

Eye close to moving onshore right over Corpus Christi, signs of Harvey slowing down as it encounters the coastline too

Central pressure down to 941mb with latest recon fix

The eye should be making landfall shortly, recon aircraft measured an estimated 130 mph surface wind in the northern eyewall at 4.20pm Central Daylight Time!

Looks more unlikely now, the BBC/Met office forecasts were hinting as such last few days, but now just going for a few 'sharp' showers clipping east Kent, whereas most models not showing anything.

Storm & Convective Forecast Issued 2017-08-25 08:06:27 Valid: Friday 25 Aug 6am to Saturday 26 Aug 6am Day 1 Convective /Storm Forecast Synopsis An upper and collocated surface low to the west of Scotland will gradually drift east across Scotland during the forecast period. Heavy showers and thunderstorms are likely across Scotland and N. Ireland, then perhaps over N England overnight. ... SCOTLAND, N of Rep. of IRELAND and N. IRELAND ... Upper low close to NW Britain will create steep lapse rates and create large scale ascent which will support scattered heavy showers and thunderstorms away from frontal cloud and rain areas. Weak vertical shear will mean severe weather is unlikely, though any heavy showers/storms will be slow-moving leading to a risk of localised flooding where they pass. Showers/storms may also produce small hail and gusty winds. Light winds aloft and surface convergence may produce funnel clouds or even a brief/weak tornado with stronger updrafts. Showers and isolated storms may continue overnight as they drift east across Scotland with the upper/surface low, lightning activity may increase along east coast as cells move out over N Sea with warm SSTs (sea surface temps) creating bouyancy. ... N ENGLAND ... As upper low crosses Scotland tonight, pool of steep lapse rates generated over relatively warm Irish Sea SSTs will support heavy showers and a few thunderstorms pushing inland and east across N England overnight. with a risk of localised flooding from stronger cells. Lightning activity may increase as cells move out over the N Sea and over warm SSTs. Issued by: Nick Finnis

Upto 35 inches of rainfall and 6-12ft storm surge http://www.nhc.noaa.gov/text/refresh/MIATCPAT4+shtml/242045.shtml

little steering flow to keep it moving inland, even if it is currently moving NW at 10-15mph overland it will have little impetus to keep that track, a look at the 50 EPS perturbations suggests many keeping Harvey hugging the Texas shoreline over 4-5 day period, quite a few taking the storm NE towards LA, the mean keeping Harvey just offshore of the central part of the Texas coast up to day 4.

Seems like it will deepen beyond a cat 1 now, the way updates are evolving Harvey so rapidly it's hard to keep up! What looked like mainly a major/disastrous inland flooding event could also have impacts of damaging winds and devasting storm surge too if it reaches at Cat 3 or worse, as some seem to be now hinting at! https://twitter.com/NHC_Atlantic/status/900735336053178370 https://twitter.com/MJVentrice/status/900735813809471489https://twitter.com/NHC_Atlantic/status/900735336053178370

Doesn't look too promising other than brief spell of rain

Nice to see reports of thunder and lightning in the SE of England, albeit isolated atm, was not depicted on my forecast map, I had SW and central S England under general thunderstorm area. But not entirely surprised that mid-level destabilisation of warm moist plume is occurring given highest CAPE has been indicated toward S England but the general consensus from various quarters that the energy will be capped. Goes to show that models are still not great at simulating mid-level convection.

Some elevated thundery showers affecting Cornwall and soon Devon atm

Storm & Convective Forecast Issued 2017-08-22 06:31:30 Valid: Tuesday 22 August 6am to Wednesday 23 August 6am Day 1 Convective / Storm Forecast Synopsis Upper and collocated surface low (the weakened remnants of ex-Hurricane Gert) will pull a plume of warm and humid air of sub-tropical origin across the UK, which will destabilise across Ireland/N. Ireland initially then across Scotland and N England Tuesday evening/night. … IRELAND, N. IRELAND, SCOTLAND, N ENGLAND and N WALES … A plume of warm and humid air advecting north across the British Isles on Tuesday, with wet-bulb potential (WBPT/Theta-w) values reaching 16-18C and characterised by steep lapse rates, will contribute to modest CAPE values reaching 300-700 j/kg ahead of cold front moving in across the far west during the evening and reaching N. Ireland, Wales and SW England early hours of Wednesday. This potentially unstable airmass will be capped across much of the UK during Tuesday, however, falling heights and cooling aloft with approach of upper low from the Atlantic combined with divergence in left exit of jet stream, shortwave trough and drier air aloft moving NE across the west will create large scale ascent which will destabilise the plume across Ireland/N Ireland initially in the afternoon … supporting development of heavy showers and thunderstorms, which will then develop or spread northeast across N England then the southern half of Scotland Tuesday evening and overnight into Wednesday morning as forcing moves NE. 30-40 knots of deep layer shear, strong upper level winds/divergence and linear forcing along/ahead of surface cold front will support organisation of convection/storms into clusters/line segments capable of producing torrential rainfall leading to flash-flooding, strong straight-line winds and hail. Increasing low level shear ahead of cold front and low LCLs (Lifted Condensation Levels or cloud bases) indicated across the west may support an isolated brief tornado too across Ireland, N. Ireland and NW England during diurnal heating cycle before risk drops after dark as surface/boundary layer becomes stable and storms become elevated. Have issued a MARGINAL risk, mainly for flooding, across Ireland, N Ireland, far N of Wales, N England and SW Scotland. ... SW / CENTRAL S ENGLAND ... There is a risk of some elevated heavy showers and thunderstorms across the above areas, mainly this morning before perhaps waning, though risk of isolated thunderstorms along S coastal areas through the day and into the evening as warm moist advection destabilises in mid-levels. Issued by: Nick Finnis

UK Severe Convective & Storm Forecast - Issued 2017-08-22 06:31:30 Valid: Tuesday 22 August 6am to Wednesday 23 August 6am Day 1 Convective / Storm Forecast Click here for the full forecastCheck the full storm forecast here

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Agree, been watching how ex-Gert interacts and in effect alters the Atlantic jet over last few days and certainly it is still causing some differences between GFS and EC ops and even the GEFS and EPS mean H500 flow as early as day 5-6. Day 6 (t+144) GFS and EC H500/SLP ops Day 6 (t+144) GEFS and EPS H500/SLP mean 00z GFS wants to track a break-away upper low / surface low with remnants of ex-Gert east across the UK next week, whilst EC keeps the low/ex Gert out west, as the W-E jet weakens, before the low dumbbells around the upper trough over the NW Atlantic and a ridge builds north further east and it warms up quite a bit across the UK next week as a result, especially the south. Further along, 00z EC warms things up nicely toward / into last week of August, as another jet streak coming out of N America dives SE and carves out a trough to our west - which draws a plume of warm air north across western/central Europe. However, wouldn't have much confidence atm past early next week, given the difference between GFS and ECM!

Storm & Convective Forecast Issued 2017-08-18 07:38:15 Valid: 18/08/2017 6am to 19/08/2017 6am Day 1 Convective / Storm Forecast Synopsis Upper trough crosses the UK during Friday, at the surface – parent low moves east to the N of Scotland while one or two surface troughs with associated occluded fronts on the southern side of the low cross the UK and Ireland. An unstable Wly veering NWly flow covers most of the UK, with a risk of thunderstorms developing with diurnal heating. … IRELAND, N. IRELAND, ENGLAND, WALES and S SCOTLAND … A wedge of rather steep lapse rates over Ireland and far west of UK this morning, associated with cold pool of mid-level air in axis of upper trough moving east, will support the development eastwards of heavy showers / thunderstorms across much of the above areas through the rest of the morning and through the afternoon … as diurnal heating increases surface instability … with GFS indicating 300-700 j/kg across large parts of the UK during peak heating this afternoon away from north Scotland … where cloudier skies and dynamic rainfall will be prevalent. Deep layer shear will be fairly weak generally, which will mean showers/storms will be disorganised and pulse-type on the whole. However, across S Ireland, S Wales and S England – stronger Wly flow aloft and 30knts+ of DL shear may organise showers/storms better into clusters/line segments capable of producing marginal risk of strong wind gusts (40-50mph), marginal risk of hail up to 2cm in diameter + marginal risk of flooding. Also, backing of winds / increase in low-level shear ahead of troughs moving through combined with local topographical effects on flow may enhance the risk of an isolated tornado too across S Ireland, Wales and SW England – where LCLs (Lifted Condensation Levels) or cloud bases will be lowest. Issued by: Nick Finnis

Lincolnshire the thunderstorm hot spot, as usual!

Looks like it was quite a lively night across parts of west Wales but especially N England. Didn't expect thunder to be so prolific across N England! Was quite an active (split) cold front ... Here was my storm forecast for yesterday:

Storm & Convective Forecast Issued 2017-08-17 08:16:18 Valid: Thurs 17th Aug 6AM to Fri 18th Aug 6AM Day 1 Storm / Convective Forecast Synopsis Upper trough over the Atlantic will approach western UK today, before the trough axis slides in across northern and western Britain overnight. A strong cyclonic SWly flow aloft with 100 mph+ jet stream across S England will lie atop a moist and unstable SWly flow at the surface. 3 areas of convective/storm focus potential likely: 1. Sern UK this morning/early afternoon + far SE tonight; 2: W Scotland , W Ireland and N Ireland today; 3. Scotland, NW England and W Ireland today and tonight. 1 ... S ENGLAND, E WALES, MIDLANDS and E ANGLIA … In wake of morning rain clearing the east coast, sunny spells developing will generate modest instability of up to 300-600 j/kg across the above areas – to coincide with mid-upper dry air intrusion with steeper lapse rates pushing in from the west on northern edge of jet across far S of England. As a result, convection may attain enough depth for a few thunderstorms amongst a swathe of showers developing from SW England/E Wales NEwards across Midlands, central S England towards Nern Home Counties and E Anglia this morning and early afternoon … before models indicate instability subsiding eastward through the afternoon. With 30-40 knts of DL shear … some organisation into clusters of shower/weak storms is possible – capable of producing localised flooding. Also hail and gusty winds may accompany showers/storms. No severe weather expected. There is a risk (albeit below 30% risk) of some isolated lightning embedded in heavy perhaps convective rainfall clipping far SE of England (Sussex & Kent) tonight, as a frontal wave moves NE through the English Channel. 2 … SCOTLAND, W IRELAND and N. IRELAND … Lapse rates will steepen through the day with approach of upper trough over the Atlantic to support heavy showers which may become weakly electrified with the addition of surface heating overland. Showers/storms maybe accompanied by hail and gusty winds, but no severe weather expected. 3 … W SCOTLAND, NW ENGLAND, W WALES and W IRELAND tonight … Heavy showers with some thunderstorms amongst them look to continue overnight across coastal areas and moving inland as increasingly cold air spreads in aloft with arrival of upper trough from the W atop seasonally warm SSTs – creating instability over the sea. Fairly strong flow aloft may organise showers/storms into linear clusters capable of brief intense rainfall leading to localised flooding along with strong wind gusts and hail may accompany stronger convection. Issued by: Nick Finnis

Chance of a few rumbles of thunder in the heavy pulses of rain spreading N and E across northern UK tonight, then later in the night a risk of some elevated storms spreading NE across parts of SE England. The overnight thundery rain clearing first thing to sunshine and showers for Tuesday, greatest chance for thunder likely to be Scotland along with northern and eastern parts of England. My latest storm forecast below. Day 1 covers tonight until 6am, day 2 cover Tuesday 6am until Wednesday 6am. Storm & Convective Forecast Issued 2017-08-14 22:07:17 Valid: DAY 1: 14/08/17 22z to 15/08/17 06z. DAY 2: 15/08/17 06z to 16/08/17 06z Days 1 & 2 Convective / Storm Forecast Synopsis Monday (Day 1): Upper trough slides in from the west across western Britain on Monday, with an area of low pressure to the West of Scotland driving a cold slowly east across northern and western areas. Heavy showers with isolated thunder will affect Ireland and N. Ireland along the cold front, then later waves moving NE along the cold front further east may produce some isolated thunder embedded in pulses of heavy rain moving NE across Wales, N England and Scotland overnight. Towards SE England, a seperate area of heavy rain and embedded thunderstorms may develop and spread NE ahead of cold front moving east. Tuesday (Day 2): Following cold front clearing eastern areas in the morning will be followed by an unstable W to SWly flow as upper trough begins to move in across the UK aloft. So scattered heavy showers and some thunderstorms are likely - more especially across northern and western areas. DAY 1 DISCUSSION ... UNTIL 6AM TUESDAY 15TH AUG ... IRELAND and N. IRELAND, SW ENGLAND, WALES, N ENGLAND, SCOTLAND ... Conveyor of warm moist air ahead of cold front and steepening lapse rates from the west with approaching upper trough will allow embedded convection near or along cold front moving in from west where lift will be enhanced by waves developing and moving NE along it. Convection may become deep enough to produce isolated thunder and locally high enough rainfall to produce localised flooding. ... SE ENGLAND ... Plume of richer moisture over France, characterised by steep lapse rates and advecting NE, may produce deep enough convection for some isolated thunder and heavy rain leading to localised flooding tonight, as mid-level warm moist air advection destabilises with approach of upper trough from the west. DAY 2 DISCUSSION ... 6AM TUES 15TH AUG UNTIL 6AM WEDS 16TH AUG ... SCOTLAND, N and E ENGLAND ... Models indicate lapse rates will be steepest across northern and eastern UK - where coldest mid-level temperatures of the trough axis moving east will be during peak heating in the afternoon. Surface heating in the sunny spells and cold temperatures aloft will support the development of scattered heavy showers and some thunderstorms. No severe weather is anticipated, given weak vertical shear and modest temperatures/moisture profiles ... any storms may produce small hail and a localised risk of minor flooding. Showers/storms should quickly fade after dark, as surface heating wanes. Issued by: Nick Finnis

Storm & Convective Forecast Issued 2017-08-07 22:04:31 Valid: 08/08/2017 00z to 09/08/2017 00z CONVECTIVE / STORM FORECAST - TUESDAY 8TH AUGUST 2017 Synopsis A deep upper trough will slide east and amplify across NW Europe during Tuesday, a potent shortwave trough moving SE across Ireland towards NW France into the base of the upper trough will aid in the deepening of a low pressure system drifting north across the near continent on the forward side of the upper trough. Thunderstorms will spread NE across France Monday night and through Tuesday, with a risk of storms developing across SE UK too, while a frontal wave further north and west will bring outbreaks of heavy and perhaps thundery rain. … SE ENGLAND and EAST ANGLIA … Plume of warm, humid and unstable air spreading northeast across France with low pressure system moving north ahead of approaching upper trough to the west looks to clip SE UK on Tuesday. Thunderstorms spreading northeast across France Monday night into Tuesday morning may spread across the eastern English Channel to affect SE England and parts of E Anglia, though 'home-grown' storms may also develop aong breeze convergence too. Storms will likely be hit and miss and with weak deep layer shear, unlikely to produce widespread severe weather … though models indicate rainfall totals that warrant a MARGINAL risk of torrential downpours leading to surface water flooding. Also light winds aloft, surface convergence and fairly low cloud bases will be ideal conditions for funnel clouds or even brief weak tornadoes/waterspouts. … CENTRAL S ENGLAND, MIDLANDS, YORKS and LINCS … Slow-moving frontal wave edging north across the above areas on Tuesday will bring outbreaks of heavy rain, waves rippling along the front may produce deep enough convection for a few embedded thunderstorms along the front which will move NE, particularly during Tuesday morning. A low risk of localised flooding may occur where convective torrential downpours develop along the front. ... IRELAND, SW ENGLAND and WALES ... Shortwave trough moving SE will create steep lapse rates with surface heating in expected sunny spells and create lift of cool but moist airmass ... which will support heavy showers and a few scattered thunderstorms which maybe accompanied by hail, gusty winds and locally torrential rain. Issued by: Nick Finnis http://www.netweather.tv/index.cgi?action=convective;sess=

Heavy downpours with occasional thunder here near Croydon after a sunny morning with towers building all around

Already been some thunder across parts of Wales and SW England, more recently over Gloucestershire/south Worcs/west Oxon Storm & Convective Forecast Issued 2017-08-05 06:47:51 Valid: 05/08/2017 06z to 06/08/2017 06z CONVECTIVE / STORM FORECAST - SATURDAY 5TH AUGUST 2017 Synopsis A strong belt of upper westerlies will cover northern Europe on Saturday, with an upper trough embedded in this flow crossing west to east across the UK. An unstable showery airmass will cover the UK, with a risk of scattered non-severe thunderstorms across southern Britain. ... E IRELAND, WALES, CENTRAL and SOUTHERN ENGLAND ... Diurnal surface heating beneath increasingly cold mid-level temperatures associated with upper trough moving east will create steep lapse rates and a modestly unstable airmass across the above areas - yielding around 300-500 j/kg CAPE. As a result, scattered showers this morning will turn increasingly heavy and more widespread across central and southern areas of England and Wales through the day, as lift from upper trough combined with increasing surface temperatures increases instability. Hail and occasional thunder is likely to accompany heaviest showers spreading east. Across S England - 30-40knts of deep layer shear towards strong jet stream and local wind convergence may organise showers/storms into clusters that may bring an isolated risk of surface water flooding. However, no severe weather is anticipated, given modest instability / shear. ... SE/E SCOTLAND ... Heavy showers developing or moving in across here may turn thundery this afternoon, with a risk of hail and localised flooding. Weak vertical shear will mean severe weather is unlikely Issued by: Nick Finnis

Looks like there will be a large swathe of severe storms over the next few days stretching from the Pyrenees NE across France, Germany and into Poland along a slow-moving boundary that separates hot and humid conditions over southern Europe and the cool and changeable conditions over NW/N Europe. Would love to be in these areas to watch supercells roll through, though could be some nasty conditions. Back home, more benign showery weather thanks to the cool conditions, but nonetheless, we could see non-severe storms today, mostly Scotland, N. Ireland and parts of N England - where lapse rates will be steepest. Chance of seeing a brief tornado / waterspout in the NW - where surface wind convergence and plenty of LL instability combined with light winds aloft will be ideal conditions for them. Storm & Convective Forecast Issued 2017-07-31 09:11:19 Valid: 31/07/2017 06z to 01/08/2017 06z CONVECTIVE / STORM FORECAST - MONDAY 31ST JULY 2017 Synopsis Upper low and collocated surface low pressure system will be parked off the west coast of Scotland during Monday. A cool and unstable showery southwesterly flow will cover the UK, surface heating will allow numerous showers become widespread away from SE UK, thunderstorms most likely for Scotland and N. Ireland. ... SCOTLAND, N. IRELAND & N ENGLAND ... An upper cold pool across northern British Isles associated with upper low centred west of Scotland will create steepest lapse rates across Scotland, N. Ireland and N England ... so here will see the greatest risk of thunderstorms developing with surface heating in sunny spells. Vertical shear will be generally weak across these areas with stronger instability, though surface wind convergence along with troughs in the flow combined with lighter upper winds may bring slow-moving lines of showers/storms that could bring a risk of localised flooding. Any storms maybe accompanied by hail and gusty winds too. Across the Western Isles, western Scotland and northern side of N. Ireland - likely local surface breeze convergence, low LCLs (cloud bases), light winds aloft and strong low-level instability will be ideal conditions for rotating non-mesocyclone updrafts, so potential for some brief tornado or waterspout sightnings here.

UK Severe Convective & Storm Forecast - Issued 2017-07-31 09:11:19 Valid: 31/07/2017 06z to 01/08/2017 06z CONVECTIVE / STORM FORECAST - MONDAY 31ST JULY 2017 Click here for the full forecastCheck the full storm forecast here