Message #8682

[martinastro]

Sunday is also showing good CAPE and LI for NI. That's a thundery potential for three days a in a row.


This from UKWW....

Synoptic Analysis and Discussion

Issued 4th May 10.30BST

Analysis & Discussion

Across the Atlantic a strong powerful Jet core (for May) is likely to maintain a very unsettled week - esp in the NW of the UK.  The First wave of this is currently spreading cloud across many parts of the UK.  HRV imagery indicates most of the UK is currently cloudy and after a chilly night (Zero to +3) across parts of Central southern and SE England - temperatures will remain somewhat depressed through the day.  There is some sunshine across the Channel Islands and the far SE, but cloud is encroaching here all the time.

Radar indicates some Moderate Rain across Wales and the Midlands (note Moderate Showers at Shawbury at 08Z) Rain & Drizzle over N IReland is not well placed by the radar due to Castor Bay currently out of the Network.

The rain largely driven by a warm advection field which is sinking south leaving a legacy of outbreaks of Rain and Drizzle across these areas.  The frontal structure across the UK is complex driven by an upper front moving south in tandem with the warm advection field  and the surface front (esp cold front) lagging behind to the NW.  This leaves most northern areas in a Psuedo warm sector.   2-5mm coming south across England today, esp on Moors and Higher ground.  Temps well depressed in comparison to recently. 12-14C - perhaps warmer in Eastern Scotland if breaks appear this afternoon.

Warmer air at 850mb as evidenced by ther 10C 850 WBPT isotherm is approaching Western Ireland ( also extensive low cloud on HRV Imagery) will sweep ESE over the next 24 hrs as the cold front slows over N ireland and N England tomorrow, the cold front thermodynamicly weak with sporadic rain and drizzle coming south. The activity pepping up through the day as a wave currently in Mid- Altantic moves east - 10-20mm coming east perhaps 30mm across the SW uplands and Mountains of SW Scotland. The warm sector covering as evidenced by 9-11C WBPT air - temperatures in any brightness responding accordingly by the surge in thickness - therefore some 7C higher across the South and esp SE tomorrow with 20C possible in any sunny spells in the SE through the afternoon, though forecast ascents look dissapointingly cloudy, nevertheless some topographical breaks occuring and leading to some sunnier spells.

A strong upper trough exiting the Canadian east coast later tomorrow induces cyclogenesis as it approaches the Right Entrance to a strong SW Jet nearing 150knts in Mid Atlantic by tomorrow night, this deepening depression looks set to combine with strong 850-950mb Warm advection and send an active warm front NE across Northern Britain through Wednesday with strong oragraphic enhancement.  Another 40-50mm possible on the mountains of W Scotland and 10-15mm elsewhere.   Strong Winds developing in the North too esp around the coasts of N IReland Scotland.  The cold front surges ESE across the UK, but weakens as dynamical forcing is lost and the driving upper trough relaxes away to the NE, leaving a weak front moving SE across the SE.

The end of the weak looks fairly cool and Showery esp in the NW with a strong upper trough covering the northern UK and bands of Showers moving east merging into longer spells of rain and partial thicknesses on the cool side of Early May, though again with most of the forcing in the north the south will remain mainly dry with only limited instability...

The main N Atlantic regime is looking decidely mobile at the moment with a strong temperature contrast across N America which is resulting in a frequent Strong ZOnal Jet nr 55N.  Pressure remains high across Western Russia and the Urals, and this leads to a lack of the pressure across Central Europe. This maintains a WNW flow across the UK with positive anomalies nr the Azores.  Little change seems indicated to this general pattern over the coming 10 days with negative anomolies remaining N of the UK and over parts of N Europe.

Paul Blight
UKww Manager - Education/Warnings