Convective Outlook

Days 4 - 8 Storm Prediction Center Norman, Oklahoma

ACUS48 KWNS 130954
SWOD48
SPC AC 130953

Day 4-8 Convective Outlook
NWS Storm Prediction Center Norman OK
0353 AM CST Thu Dec 13 2018

Valid 161200Z - 211200Z

...DISCUSSION...
Guidance continues to indicate that relatively cool and/or dry
conditions over much of the Gulf of Mexico late this weekend into
early next week will be slow to modify.  This will contribute to the
maintenance of stable conditions with low convective potential
across much of the U.S., which otherwise will remain under the
general influence of split branches of westerlies downstream of a
strong zonal mid-latitude Pacific jet.

Deterministic and ensemble output of the medium-range models suggest
that the predictability of periodic amplification of short wave
perturbations within this regime remains low.  This includes one
possible amplification indicated by some guidance (including recent
runs of the ECMWF) across and east of the Mississippi Valley during
the middle to latter portion of next week.  It appears that there
could be phasing with a belt of westerlies emanating from the
subtropical eastern Pacific, and this may be accompanied by
cyclogenesis supportive of organized severe weather potential across
parts of the Southeast (particularly Florida into southern Mid
Atlantic coastal areas) next Thursday.  However, due to the
uncertainties associated with low predictability, severe weather
probabilities remain less than 15 percent at this time.

..Kerr.. 12/13/2018