Changeable weather heading toward Christmas 

Posted: 9:58 am Monday, December 18th, 2017

By Kirk Mellish

A couple wild jet stream pattern swings are expected over the remainder of the month, with an active couple of weeks there will be some excitement and some news-making weather.

The models are still struggling with the extremes and I suspect that will continue to be a problem.

TODAY:

93fndfd_init_2017121800

LATE TUESDAY:

98fndfd_init_2017121800

WEDNESDAY:

noaad3

GA_swody3

MORE FRONTS TO COME:

Screen Shot 2017-12-18 at 9.33.17 AM

AND A CHANGING JET STREAM:

cpc_NAM_f192wbg

cpc_NHEM_f264wbg

Resulting in changing temperatures next 16 days from above to below normal:

gefs_t2anom_16_noram_1

eps_tsnow_m_conus2_32

Confidence in the extended range 7-16 days is lower than normal due to wildly unstable and varying model output that has shown just about every scenario in that time frame and flip flopping back and forth everyday. In general it looks like winter prospects will grow beyond Christmas. But it seems pointless in a pattern full of chaos to attempt a specific forecast for the 24th/25th as the signals from the data look like this:

Screen Shot 2017-11-14 at 5.33.03 AM

Here are the temperature ENSEMBLE TRENDS:

KRYY_2017121806_min_max_16KMGE_2017121800_eps_min_max_15

Screen Shot 2017-09-08 at 6.09.43 PM

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Of course this can happen in a short-term forecast, too. But the variance grows with distance into the future.

DRU-TraVoAEADW1

Their graphic similar to the point I made in tweet Saturday:

Screen Shot 2017-12-18 at 10.51.09 AM

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