|Monday, May 14, 2007 - 3:30PM EDT
June? Forecast update for May 14
I've been waiting all day for the last of the 12Z model runs to come out before posting this update (the ECMWF is always dead last in the update sequence), but even before then I was rapidly losing confidence in the trough forecast for May 21-24. The 12z models confirm the concerns. The trough will be a far northern Plains and even Canadian event, and a very short-lived and marginal one at that - maybe able to squeak out one or two storm observation days. The probabilities for tornado intercepts at this stage, while still present, just look too low for us to consider at this point. The models have been fairly consistent and in agreement about this pattern, which means the likelihood of a major about-face of the forecast pattern is low.
After the small May 21-24 trough pushes eastward, the models suggest another stout ridge locking itself in place across the central USA, shutting down severe weather on the Plains for another extended time. This is pushing back the possibility of a western trough, and our departure, beyond June 1. June is getting higher probabilities in our table simply because it is looking like the last chance for something to happen before our standby period ends on the 15th. Due to 1.) our high standards for the upper air and surface patterns, 2.) there being only two more weeks beyond the ridged-out pattern during June 1-15, and 3.) the fact that we've already completed two full trips - means that the 'no trip' probability unfortunately must increase as well.
Based on the current outlook, this probability table charts the chance of our trip starting on a particular date:
|2007 Weather Expedition - Departure Date Probability as of May 14|
|May 26-June 2||25%|