Model: GFS Ensemble
Update: 4 times per day, from 00:00, 06:00, 12:00 und 18:00 GMT
Greenwich Mean Time: 12:00 GMT = 13:00 BST
Variables: Temperature at 850 hPa and Precipitation
Description: The curves indicate both the general weather patterns, especially temperature and precipitation, and the general level of confidence of the forecast run. If the curves are plotted closely together, usually the initial 3-4 days, confidence is good. Confidence level is becoming poor where the curves begin to spread and forecast credibility starts gapping.