Winter Storms.. So Hard To Predict

[Brandon Sullivan]

Low Pressure Systems associated with winter storms have sooo many variables.. The slightest moisture/temp/path/strength/warm vs cold sector/ can have massive effects on the storm.. A typical mid latitude cyclone, associtated with summer severe wx, can produce severe weather, in a variety of conditions. If the environment lacks shear, it may be able to make it up in CAPE and other forms of instability. And vice versa. In the summer, being in the warm and cold sector, doesnt really have much of an effect as temps dont really differ as much.. Maybe it is just me.. But it would seem, that a winter storm hold more bust potential.. With more variables, that can effect the final results.

 

[Justin Turcotte]

I find winter storms easier to forecast since they are generally driven by sysnoptic scale processes. There are certainly mesoscale features to deal with such as banding and lake effect snow but on the whole you are dealing with synoptic scale lift and the models are far superior on the synoptic scale than the mesoscale. For me, the toughest part of a winter storm forecast is start time (saturation), precip type, and time of changeover for differing types. Lake effect storms offer additional challanges (huge difference in snow over very small areas) Models seem to do a better job on the synoptic scale during summer since systems tend to move slower. Slower propagating systems mean less dramatic changes moving through data voids and a couple extra model runs to pin things down. One of the biggest challanges for a convective forecast and especially a severe convective forecast is resolving the mesoscale features a couple days in advance if even possible in some cases. I've always said day 2 convection is a function of day 1 convection. The synoptic features like fronts are probably well advertised/forecast but figuring out where the OFB is going to be or finding that sneaky 700-mb wave can be quite challenging. Models simply don't handle these small scale features well with much lead time. IT may be interesting to nore the NWS will put out a winter storm watch some 30 hours in advance but the SPC will rarely put out a severe storm or tornado watch box more than 6 hours in advance. This should show the degree of confidence the forecasters have for each situation.