There remains a fair degree of uncertainty as to exactly where across northern England the rainfall will be most persistent/heaviest and consequently where the largest accumulations will be, and also how those accumulations will translate into impacts. The latest data to hand places the largest rainfall totals across the central, S and SE’ern parts of Cumbria and just over the border into N Yorkshire but all will depend upon how what is a complex meteorological set-up, resolves itself.
General weather sequence:
Tomorrow’s rain will reach Lancashire and then Cumbria approximately between midday and early afternoon. Thereafter it’s a case of outbreaks of rain, heavy at times, especially over the higher ground, through until later on Saturday. The rain will likely wax and wane, both in areal extent and in intensity, with a few drier interludes from time to time. As Saturday progresses so the rain should become lighter and increasingly fragmented.
Severe weather warning status:
Yesterday’s amber rainfall alert covering approximately the eastern two thirds of Cumbria remains in force and has just been updated (see attached). The risk rating remains the same (medium likelihood of medium level impacts) as does the validity time (from midnight tomorrow night until midnight Saturday/Sunday).
Also please note that a separate yellow alert for rain also remains in force (low likelihood of medium level impacts) across the rest of Cumbria and Lancashire N of approximately Preston, valid from 1500 tomorrow afternoon until midnight Saturday/Sunday (attached above). Both these warnings are subject to constant review and may be updated again later today.
This morning’s Flood Guidance Statement (FGS) shows Cumbria on yellow (low flood risk) through Friday then amber (medium flood risk) during Saturday and back to yellow for Sunday for residual river impacts. Lancashire remains on yellow throughout the weekend. The flood risk through the period will be a combination of surface water-based impacts and those due to river response.
Looking beyond Boxing Day:
Sunday is looking largely dry, once any residual light rain has cleared up. However, further rain is expected in sometime during Monday and again later on Tuesday. Amounts hard to specify at this time range but one thing to note is the potential for some very strong winds as we head towards the middle of next week. More on this aspect once we’ve got the weekend’s rainfall dealt with.
For the latest information please refer to the following places:
The latest from Sue: A significant amount of rainfall is predicted from tonight through to Sunday. The flood gates will be closed today. The river levels may rise above the levels from the previous weekend. As always stay vigilant, I will keep you updated. For up to date news see our Flood Group Facebook Page.
The latest from the Met Office: A difficult, testing period coming up for Cumbria in particular from this evening through until early Sunday with yet another major ‘orographically induced’ rainfall event kicking off this evening and lasting throughout Saturday before eventually relinquishing its grip overnight into Sunday. Allied to this will be periods of very strong S to SW’ly winds tonight and during Saturday with potential for significant additional disruption from the wind itself, let alone the flooding issues brought about by the rain.
I’ll deal with the two threats separately.
RAINFALL – CUMBRIA & N LANCASHIRE:
The rain looks set to arrive into Cumbria from the NW during the first half of this evening. Once in it looks set to intensify and continue pretty much unrelenting for the remainder of tonight and right throughout tomorrow, heaviest over the central fell area, occasionally waxing and waning in extent/intensity. Some of the rain will spill over into North/Northeast Lancashire but the really big accumulations will, as always, be focussed upon the central Lakes/Fells area.
Yesterday’s yellow alert for rain has been escalated up to amber for much of Cumbria with a high likelihood of medium level impacts, valid 0200 Saturday to 0600 Sunday. A copy of the amber warning is attached above. A separate yellow warning (low likelihood of medium impacts) has also been issued to cover those parts of Cumbria and N Lancashire not included in the amber sector, valid midnight tonight until 0900 Sunday. This morning’s Flood Guidance Statement (FGS) is showing Cumbria at Yellow (low flood risk) for today to take account of any impacts resulting from this evening’s rain. Then for the weekend the FGS is Amber (medium flood risk) across Cumbria with Lancashire at Yellow (low flood risk). The flood risk will be a combination of river and surface water-based impacts with the river component of the flood risk carried over into Monday across both counties (yellow). Please refer to the Flood Guidance Statement for a full description of the flood risk throughout the weekend and beginning of next week, including the situation on the River Dee in west Cheshire. Back in Cumbria and N Lancashire disruption to transport, both road and rail, from surface water flooding, looks sadly inevitable from later tonight onwards right into early Sunday morning as water runs off the already very wet ground. Some key routes across Cumbria may well be adversely affected by the excess surface water.
STRONG WINDS – WHOLE REGION:
The S to SW winds will start to freshen up through this afternoon and then maintain their strength throughout tonight and tomorrow, eventually moderating down in the early hours of Sunday. The strongest winds will be across Cumbria, N Lancashire and the western Pennines with Cheshire and Merseyside the areas least affected. Two separate wind warnings have been issued, one for today and one for all of tomorrow up until 0600 Sunday. Both are attached above for reference. Today’s warning suggests a high likelihood of low impacts and reaches down roughly as far south as Liverpool to Manchester. Gusts could reach 45 to 55mph this evening with 60 to 65mph possible along exposed sections of coast and over the higher level routes. Tomorrow the winds, if anything, look slightly stronger, especially over Cumbria, with gusts of up to 70mph possible, even at lower levels, although there will no doubt be some ‘favoured’ spots that receive the bigger gusts whilst others areas are spared. We’re all in the warning zone tomorrow and the risk rating shows a low likelihood of medium impacts. The warning picks out tomorrow afternoon and evening as a possible time when the gusts will be at their strongest, something worth bearing in mind.
Impacts from the winds, as specified in yesterday’s briefing, will include all the usual suspects – high-sided HGVs on the roads and possibly not just confined to the higher level routes such as Shap. The main bridges in the region (Thelwall, Barton, Silver Jubilee) are all likely to be adversely affected. Numerous trees will doubtless be brought down – some no doubt landing on roads and possibly, as per recently, the West Coast Main Line or other sections of railway line. Unsecured structures will pose a risk and as for outdoor festive markets – it’s hard to see any of these being able to function properly tomorrow, unless they are completely sheltered from the wind. Not a good time to be out tomorrow afternoon/evening, especially in Cumbria and N Lancashire with the added problems posed by the rain.
BEYOND THIS EVENT:
Sunday will finally bring some respite from both wind and rain, before the next Atlantic weather system shunts a fresh band of rain northwards across the region overnight into Monday with further rain crossing all areas the following night. Rainfall totals during Monday and Tuesday should be a lot less than what will fall over Cumbria tonight and tomorrow but, given the sensitivity of the catchments to further rainfall, we’ll have to keep a very careful eye on things. There is a hint of something drier coming along during Tuesday and Wednesday of next week.
The rain across Lancashire and Cumbria has now diminished to little more than a few patches here and there and with the situation on the ground improving so the afternoon edition of the Flood Guidance Statement was able to show a reduced flood risk from amber to yellow with a low likelihood of significant impacts still applying to both counties. In tandem with this the Met Office amber warning was cancelled just after 1500, leaving the region under a single yellow warning, the graphical bits of which are displayed below. As you can see it’s now only N/NE Lancashire and Cumbria still at risk from any significant impacts over the next 12 hours. The upcoming feature of concern is the rain band associated with the transition to clearer conditions, set to move in between approx 2100 and 2300 this evening. There’ll be some heavy rain on this, especially over Cumbria, but it should be a relatively short-lived affair and even allowing for a few showers in the early hours of Monday, additional accumulations of rain will be modest in comparison with what fell earlier today and overnight. The power of the Cumbrian mountains to generate rain when fed the right air supply never ceases to impress and the EA gauge at Seathwaite recorded 178mm in the 12 hours to 0845 this morning. However, one didn’t have to travel very far out from the central fell area of the Lake District to see the totals tail off rapidly.
As for tomorrow night’s weather system – still some uncertainty as to the northern edge of the associated rain area but hopefully it will stay wholly to the south of Cumbria and N Lancs. The next system, following quick on its heels, will likely take a more northern track and further rain looks a surer bet during Tuesday.
In the meantime have a good rest of Sunday,
Alan Goodman; Met Office Advisor (Civil Contingencies)