Convective Addiction

Mid-February Thaw – Part II

Posted on 13. Feb, 2011 by Jesse in Uncategorized

As we continue to watch what appears to be at least a temporary (and optimistic) pattern change, the medium and long-range models are advertising some tantalizing respite from the arctic blasts and adverse winter weather which have been slamming the CONUS the past few months.  For more on the teleconnections associated with this sudden respite from a breath of tundra, please see Part I here.

As the AO trends neutral-positive, it appears that high pressure will take residence over the Gulf-Atlantic region the next 7-10 days as the upper-level flow fluctuates between a quasi-zonal and a more southwesterly flow.  This synoptic pattern will allow warmer air to move northward across parts of the Midwest, opening up the Gulf of Mexico for a few late winter WAA migrations northward. One limiting factor for slightly warmer temperatures initially will be the hard snow pack that remains over parts of the Midwest, but that is slowly receding as noted in this image.

Meanwhile, a troughing pattern will set-up over the western CONUS as a series of disturbances with associated surface cyclones will gyrate eastward.  While there is every reason to believe that the actual progged moisture advection on the surface profiles are well overdone, it does hint that several of these potential systems would have more ample moisture to work with.  This could mean some more late winter snows for parts of the Plains and/or the Upper Midwest, and it could even mean a first shot at least for some marginally severe weather, even if convection is elevated, for parts of the Mississippi Valley and Dixieland.

While it’s simply not prudent to try and speculate how any of this will actually evolve, the models seem to be hinting at a much more active pattern as meteorological winter comes to a close in two weeks.  It’s certainly fun to see what the medium and long-range numerical models are forecasting, and then checking back over the next week or so to see how reality actually compares to current prognostications.

While probably overdone, the dewpoint pattern offers assurance that moisture is available and willing to elope.

Upper-level jet pattern reveals troughing pattern in the western CONUS

Several surface cyclones progged to gyrate across the CONUS

Stay tuned, as it appears March might come in like a lion.

JLR