Nick F

Senior forecaster
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About Nick F

  • Rank
    Specialising in severe weather
  • Birthday 08/09/75

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    Male
  • Location
    South Norwood, London (home), Hounslow/Heathrow (work)
  • Interests
    Weather - particularly thunderstorms, growing plants, walking, cycling, cooking and good food, wine.

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  1. Storm & Convective Forecast Issued 2016-07-22 09:16:18 Valid: 22/06/2016 0600z to 23/06/2016 0600z CONVECTIVE/STORM FORECAST - FRI 22ND-JULY-2016 Synopsis An upper trough will slide east across the UK and western Europe as an extension of upper low complex over the far North Atlantic, a slack but moist surface airmass across the UK will become unstable to surface heating this afternoon ahead of an occluded front moving across the west today, with heavy showers and thunderstorms developing in places. ... ENGLAND, WALES and ERN SCOTLAND ... The slack/weak surface flow across much of the UK will feature several convergence zones across the above areas, which will tend to strengthen as the day goes on due to surface heating inland creating strengthening sea breezes to spread inland. A moist airmass, (characterised by dew points of 15-17C) and surface heating into the low to mid 20s deg C will generate around 300-600 j/kg CAPE. Lapse rates don't look particularly steep on GFS progs, which will prevent greater instability generally, so thunderstorms will tend to be confined to convergenze zones where strongest updrafts will establish. Given high moisture content of the atmosphere across the above areas (PWAT values of 27-30mm) and weak upper winds, slow-moving torrential downpours leading to localised flash-flooding will be the main threat from any storms. Have issued a MARGINAL risk for flooding for SW England, parts of central S and SE England, E Midlands and parts of E England - as strongest convergence/storms seem most likely here this afternoon. Any hail will tend to be isolated and small given modest CAPE, weak winds aloft and surface convergence will favour the development of a few funnel clouds. Issued by: Nick Finnis
  2. UK Severe Convective & Storm Forecast - Issued 2016-07-22 09:16:18 Valid: 22/06/2016 0600z to 23/06/2016 0600z CONVECTIVE/STORM FORECAST - FRI 22ND-JULY-2016 Click here for the full forecastCheck the full storm forecast here
  3. Not often you see a UK radiosonde ascent show 1000+ j/kg CAPE, strongly unstable atmosphere today by UK standards, this is the noon ascent for Nottingham. The wind profiles were all wrong to produce a tornado, with a westerly flow at the surface and winds backing Sly aloft (should be other way round). Nonetheless, 1300+ CAPE was enough to produce strong updrafts sufficient to make large hail and also produce frequent lightning. This water vapour loop for this afternoon/evening shows mid-level trough and associated dry air (dark stripe) and its positive vorticity swing east which enhanced lift to create the storms from the Midlands down to E Anglia, surface cold front marking back edge of this dry air intrusion. http://brunnur.vedur.is/myndir/seviri/2016/07/20/seviri_eurnat_wv6-2.html
  4. Storm & Convective Forecast Issued 2016-07-20 07:46:47 Valid: 20/07/16 0600 to 21/07/16 0600z DAY 1 CONVECTIVE / STORM FORECAST - WEDS 20-JULY-2016 Synopsis Upper ridge across western Europe including the UK continues to decline southeastward to allow the edge of upper trough over the Atlantic to move in across the far west of British Isles. A hot and humid plume across much of the UK has become unstable across the north and west overnight, as the upper trough edges in from the west. Forcing for ascent of hot and humid air by approaching upper trough, shortwave trough ejecting NE and developing surface low moving NE ahead of a surface cold front moving in from the west will lead to an increasing extent of thunderstorms across northern and central areas on Wednesday, some of these storms may be severe given favourable convective parameters. … N WALES, MIDLANDS, N and E ENGLAND and SCOTLAND … Overnight storms across northern Scotland will gradually clear this morning, but another area of storms, a MCS (Mesoscale Convective System) is ongoing to start the day across N Wales, NW England and SW Scotland. This MCS will shift NE this morning across NW England and Scotland and will continue to affect eastern Scotland through the afternoon. The main risk from these storms this morning will be torrential rain leading to flash flooding and frequent cloud-to-ground lightning. Fresher and more stable conditions across EIRE and N. Ireland this morning will arrive across western Scotland, Wales and SW England this afternoon, with risk of storms diminishing here, as cold front moves in from the west. However, ahead of the cold front, storms may re-develop across SE Scotland, N England, parts of the Midlands and perhaps eastern England (where they will be more isolated) as temperatures rise combined with increased forcing for ascent from approaching upper trough, shortwave moving NE and surface low across SW UK in the morning moving NE. Despite modest deep layer shear (20-30knts) – fairly strong low-level shear combined with 1000-1500 j/kg CAPE across N England, Midlands and E England may favour the development of strong and perhaps severe thunderstorms capable of producing large hail (2 to 3cm in diameter), damaging wind gusts, frequent lightning and flash-flooding. Given backed SEly flow initially across N Sea coasts, high CAPE and low LCLs (cloud base) … there is a small risk of a tornado or waterspout across NE England and SE Scotland. Have issued a MODERATE for severe storms across SE Scotland and N England for the risk of large hail, damaging winds, flash flooding and small risk of a tornado. A SLIGHT risk covers elsewhere across northern Britain for the risk of large hail, flooding and damaging winds. Issued by: Nick Finnis
  5. UK Severe Convective & Storm Forecast - Issued 2016-07-20 07:46:47 Valid: 20/07/16 0600 to 21/07/16 0600z DAY 1 CONVECTIVE / STORM FORECAST - WEDS 20-JULY-2016 Click here for the full forecastCheck the full storm forecast here
  6. Storm & Convective Forecast Issued 2016-07-19 09:04:37 Valid: 19/07/16 1800z to 21/07/16 0600z DAYS 1 & 2 CONVECTIVE FORECAST - TUES 19TH and WEDS 20TH JULY Synopsis Upper ridge across western Europe including the UK begins to decline southeastward to allow the edge of upper trough over the Atlantic to move in across the far west of British Isles. A hot and humid plume spreading north across much of the UK will become increasingly unstable across the north and west as the upper trough edges in from the west over the next 24-36 hours. Forcing for ascent of hot and humid air by approaching upper trough and developing surface low moving NE ahead of a surface cold front moving in from the west will lead to an increasing extent of thunderstorms across northern and western areas from Tuesday evening through to Wednesday evening, some of these storms may be severe given favourable convective parameters. DAY 1 CONVECTIVE FORECAST – TUES 19TH-JULY-2016 Valid 19/07/16 1800 to 20/07/16 0600z … EIRE, N. IRELAND, N WALES, N ENGLAND and SCOTLAND … Hot and humid plume spreading north across the UK over the last 24hrs will yield quite large amounts of CAPE (by UK standards) today with surface heating, GFS indicates 1000-2000 j/kg CAPE across large areas of the UK and EIRE this afternoon. This potential energy will be strongly capped by upper ridge, but heights will weaken across the NW this evening with approaching upper trough from the west as ridge declines. Increasing large scale ascent this evening across EIRE, N. Ireland into western Scotland created by approaching upper trough and additional ascent from shortwave trough rounding the upper trough to the west and moving NE will likely trigger scattered thunderstorms. Storms increasing in coverage and extending NE to affect more of Scotland and also north Wales and northern England. Given the large CAPE values forecast, 30-40 knots of deep-layer shear and surface winds backed SEly from SWly flow aloft … any storms that form are likely to organise into multicell clusters, a few supercells can’t be ruled out initially before storms tend line out into clusters. As storms will tend to be elevated, main severe threat from storms this evening and overnight will be excessive rainfall (30-40mm per hour or up to 50mm over a few hours) which may lead to flash-flooding locally. Strong and perhaps isolated damaging wind gusts are also possible. Given high CAPE values – isolated large hail (2 to 3cm diameter) can’t be ruled out with evening storms before hail risk subsides. Frequent lightning will also be a hazard. Therefore have issued a SLIGHT risk of severe weather for the above areas. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ DAY 2 CONVECTIVE FORECAST – WEDS 20TH-JULY-2016 Valid 20/07/16 0600 to 21/07/16 0600z … N WALES, MIDLANDS, N ENGLAND and SCOTLAND … Thunderstorms, perhaps locally severe, will be ongoing to start the day across EIRE, N. Ireland, N Wales, N England and Scotland. These storms may wane through the morning across these areas, before drier and fresher conditions spread across EIRE, N. Ireland and western Scotland in the afternoon and Wales in the evening, as cold front moves in from the west. Storms re-developing across eastern Scotland, N England, N Wales and parts of the Midlands ahead of cold front as temperatures rise combined with increased forcing for ascent from approaching upper trough and as surface low across SW UK in the morning moves NE and deepens slightly. Despite modest deep layer shear (20-30knts) – fairly strong low-level shear combined with 1000-1500 j/kg CAPE across Midlands, N England and S Scotland may favour the development of strong and perhaps severe thunderstorms capable of producing large hail (2 to 3cm in diameter), damaging wind gusts, frequent lightning and flash-flooding. Given backed SEly flow initially across N Sea coasts, high CAPE and low LCLs (cloud base) … there is a small risk of a tornado or waterspout across NE England and SE Scotland. Have issued a SLIGHT risk for now, but may upgrade to MODERATE risk if severe storms look to be more extensive. Issued by: Nick Finnis
  7. UK Severe Convective & Storm Forecast - Issued 2016-07-19 09:04:37 Valid: 19/07/16 1800z to 21/07/16 0600z DAYS 1 & 2 CONVECTIVE FORECAST - TUES 19TH and WEDS 20TH JULY Click here for the full forecastCheck the full storm forecast here
  8. Not had chance to do a proper storm forecast for next few days, though have mentioned in my blog Brief Heatwave & Thunderstorms - What To Expect the potential for severe storms from the Midlands/S Wales nothward from late Tuesday through to late Wednesday before a surface cold front sweeps the very unstable, hot and humid air away eastward from the UK Wednesday night
  9. A blog looking at the brief heatwave peaking on Tuesday across the UK, before a thundery breakdown spreads from the west across northern and western areas on Wednesday, then cooler and fresher conditions return Thursday. View the full blog here
  10. Risk of a few isolated heavy thundery showers developing across southern counties this afternoon looking at morning models, probably result of a sea breeze front developing inland as warmth builds inland and pressure falls to allow sea breeze to develop. Does look like northern and western areas will be prime areas for storms as the breakdown starts from the west later on Tuesday. Thunderstorms developing across EIRE, N. Ireland, NW England and SW England during Tuesday evening, before these storms rumble northeast across Scotland Tuesday night. Thunderstorms ongoing or reveloping across northern and western areas on Wednesday, further south across Wales and SW England too, perhaps some severe storms developing from SE Wales, NE across the Midlands to E and NE England too, looking at 00z ECMWF, as an area of low pressure moves NE along the cold front. Detail subject to change at this range though.
  11. Back from being away with a storm forecast for today, given light winds aloft main threat will be flash-flooding from slow-moving storms training along wind shift zone shifting SE across SE England and E Anglia. Storm & Convective Forecast Issued 2016-07-12 09:28:53 Valid: 12/07/2016 06z 13/07/2016 06z CONVECTIVE / STORM FORECAST - TUES 12TH-JULY-2016 Synopsis Upper trough extends south to Iberia from upper low centred south of Iceland, with deeply cyclonic westerly flow across the UK. Coldest mid-level temperatures and thus steepest lapse rates will be towards SE Britain on Tuesday, so central and eastern counties of England will see the greatest risk of thunderstorms today. ... MIDLANDS, SE ENGLAND and EAST ANGLIA ... A combination of highest moisture (dew points of 12-13C), highest temperatures (18-20C) and coldest mid-level temperatures will produce greatest instability across the above areas - with 300-600 j/kg forecast to develop this afternoon with surface heating. As a result, heavy showers and thunderstorms will likely develop. Despite lack of vertical wind shear, a wind shift/convergence zone shifting southeast across Thames Valley/E Anglia will organise bands of storms which will be slow-moving given light winds aloft ... so there is risk of prolonged torrential downpours leading to flash-flooding in some places. Therefore have issued a MARGINAL risk for SE England and E Anglia. A few storms and more heavy showers will continue across the SE and E Anglia into the night, perhaps merging into a longer spell of heavy rain, bringing a continued risk of localised flooding, before rain clears away eastward first thing on Wednesday morning Issued by: Nick Finnis
  12. UK Severe Convective & Storm Forecast - Issued 2016-07-12 09:28:53 Valid: 12/07/2016 06z 13/07/2016 06z CONVECTIVE / STORM FORECAST - TUES 12TH-JULY-2016 Click here for the full forecastCheck the full storm forecast here
  13. Spain and Portugal still in the grip of a heatwave this week after 44.5C was reached in Cordoba on Sunday. More moderate heat elsewhere in southern Europe, but northern Europe including the UK at mercy of cool Atlantic flow. View the full blog here
  14. Storm & Convective Forecast Issued 2016-07-01 08:59:18 Valid: 01/06/2016 06z to 02/06/2016 06z CONVECTIVE / STORM FORECAST - FRI 1ST-JULY-2016 Synopsis Unseasonably deep upper low moves in across NW Britain on Friday, with a deeply cyclonic southwesterly flow across the UK. Surface low will move slowly NE to the NW of Scotland, cold front clearing SE England in the morning will be followed by a cool and showery maritime flow, with surface heating allowing a few thunderstorms to develop. … EIRE, N. IRELAND, SCOTLAND, N WALES, N ENGLAND, N MIDLANDS … Cold pool associated with upper low moving in across the NW will steepen lapse rates across the above areas through the day … which with surface heating of moist maritime flow will contribute to around 300-600 j/kg CAPE this afternoon. As a result, heavy showers already across EIRE/N. Ireland and western Scotland will become more widespread across the above areas through the day, with increase in surface heating leading to the development of scattered thunderstorms. Deep layer shear will be weak across Scotland and Ireland … so storms will struggle to organise. Better overlap of stronger shear (40-50 knots) near jet stream across the south and instability will exist across N Wales, N England and N Midlands – where storms may potentially organise to bring a risk of localised flooding, hail to marble-size and strong wind gusts. Generally, organised storm risk looks below severe probabilities, given cool temperatures / modest instability. Issued by: Nick Finnis
  15. UK Severe Convective & Storm Forecast - Issued 2016-07-01 08:59:18 Valid: 01/06/2016 06z to 02/06/2016 06z CONVECTIVE / STORM FORECAST - FRI 1ST-JULY-2016 Click here for the full forecastCheck the full storm forecast here