Thursday, February 13, 2014

February 22-24 Potential Severe Weather Event

Model guidance is latching on to the idea of a severe weather event in the February 22 to 24 timeframe.

Tropical Tidbits
The GFS model brings unseasonably warm temperatures north on February 22nd, as the graphic above shows. Projected temperatures range mainly in the 60s and 70s, where the warm sector is exerting the most influence. We see the cold front clearly defined, stretching through the Plains and Upper Midwest, with the warm front pulling that warm, moist air far to the north in what would likely be a set-up for the first severe weather event of the season.

Tropical Tidbits
Jet stream analysis from this same GFS model shows the storm system positioned in Wisconsin as a strong 988 millibar low pressure system. We see a jet streak in the 130 knot range positioned to the east of the trough, indicating the storm has become negatively tilted and is expected to continue lifting north and east. These strong jet stream winds, combined with the warm and moist air (containing up to 1.6" of precipitable water across the warm sector), would likely produce a severe weather event. The negative tilt of the trough, shown below, would further enhance severe weather prospects.

Tropical Tidbits
The negative tilt of the trough, shown best when maximum vorticity values are positioned on the eastern side of the trough and contour lines seem to be pressing in a southeast direction, indicates that the storm system has reached maturity, and is therefore more able to produce significant weather. In this particular case, with temperatures only projected to be in the 60s, PWAT values to only be around 1.6", and the jet stream maxing out at 130 knots, I wouldn't be holding my breath for a big severe weather outbreak. However, this solution looks good for at least some severe weather.

Tropical Tidbits
The 700mb winds and vorticity chart for February 12th shows us that lower level winds will be reaching into the 40 knot and 50 knot range, which, while not all that impressive, solidifies my concerns that this may still be a severe weather event, albeit not as intense as a full-out "outbreak".

Because this event is still in the long range, model guidance will inevitably change with this storm system. It is possible we don't even see a severe weather event at all, and it's also possible the severity of this event increases as we get closer to the event. I would bet my money more on the weakening prospects, as the atmosphere still looks a little 'wintry' to me, if you will, and doesn't seem all that conducive for a big severe weather event.


1 comment:

Anonymous said...

I am hearing about a big warm in the mid Atlantic states and people are saying that it marks the end of winter. Is this true or will cold air fight back by the end of the month