Change in Forecast

March 27, 2007

SnapshotA challenging forecast season continues the next few days…ugh!  The rain and clouds were slow to leave today, although in the end the gusty northwest wind and partly cloudy skies arrived, just a bit late.
The cold trough is shifting off to the east tonight, leaving us waiting for another chilly trough to arrive late this week.  Two changes to the forecast for the next 5 days.  One is the surprisingly dry and warm weather the next two days, especially Thursday.  I notice our model shows some very weak convection over the Coast Range early tomorrow afternoon, although it does not show it drifting out over the valleys.  Hopefully it stays that way. 
Since the next system doesn’t move inland now until Friday afternoon, that leaves ridging ahead of it and brief warm easterly downslope wind Thursday.  All models have boosted 850mb. temps up to +6 or higher (Celsius).  This easily supports mid 60’s this time of year…so the forecast high Thursday just jumped about 10 degrees!
Showers arrives sometime Friday, but then move out quickly by Saturday morning.  The 2nd significant change in the forecast is for Sunday.  00z models continue a trend of bringing a weak system through N. California and up into Oregon on Sunday.  If so, we may see rain showers Sunday.  Longer range models are all over the place after that time.  I DO notice the GFS doesn’t have much rainfall in the next 7 days…it’s looking more like spring…Mark