Storm Forecast
Valid: Fri 24 Nov 2006 06:00 to Sat 25 Nov 2006 06:00 UTC
Issued: Thu 23 Nov 2006 22:49
Forecaster: DAHL
SYNOPSIS
Upper flow over W and central Europe is expected to back somewhat as Atlantic upper trough amplifies in response to a vort max rounding the base of the trough. Vigorous SFC cyclogenesis is expected to accompany this vort max, affecting the Iberian Peninsula and the British Isles on Friday and Friday night. Otherwise, weak quasi-stationary upper trough persists over the E Mediterranean regions.
DISCUSSION
... Aegean region ...
It seems that thunderstorms will persist over the Aegean region, and eventually move eastward beyond the forecast area's boundaries late in the period. CAPE and shear are expoected to be minimal and severe threat should be accordingly low, though an isolated waterspout or two cannot be ruled out.
... British Islea ... France ... Iberian Peninsula ...
Challenging forecast over Iberia, France, and the British Isles. GFS is somewhat reluctant to come up with appreciable and deep CAPE along and ahead of the cold front associated with the developing Atlantic SFC low. NMM is somewhat more optimistic but has overestimated convective potential for Thursday and so little confidence is put in this solution at this time. Most likely scenario seems to be that quite widely scattered storms will develop along the cold front over Iberia and maybe France but coverage will likely remain quite low. Those storms that do form will have some severe potential given quite impressive shear profiles but activity should be too isolated to warrant a thunderstorm/categorical forecast. Highest chances for more focused activity may exist over the central British Isles late in the period where latest GFS runs indicate some CAPE late in the period. Massive shear will be in place ... and this activity may augment the already severe large-scale wind field ... and also produce a couple of tornadoes. This forecast is still somewhat uncertain, especially over France and the Iberian Peninsula and an update may be necessary on Friday.
