Day 1 Outlook Day 2 Outlook Day 3 Outlook Days 4-8 Outlook

Day 1 Outlook Convective Tornado
Hail Wind
Categorical Day1 1300Z Outlook
Images courtesy of the NWS Storm Prediction Center
 Forecast Discussion

ACUS01 KWNS 171238
SPC AC 171237

Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0637 AM CST Wed Jan 17 2018

Valid 171300Z - 181200Z


No thunderstorm areas are expected today or tonight.

A highly amplified, yet progressive pattern characterizes the
middle/upper levels over the contiguous U.S.  A cyclone is forecast
to develop over the southern Appalachians today, in the basal region
of a positively tilted synoptic trough now extending from QC to OH,
western TN and LA.  That cyclone should move offshore from the
Tidewater region of MD/VA/NC around the end of the period.  The
associated deep surface cold-frontal penetration over the Gulf and
western Atlantic will render the air mass east of the Rockies too
stable for thunderstorms, while upstream ridging aloft over the
Intermountain region and Rockies yields the same result there.

...Pacific Northwest...
Moisture-channel imagery shows a broad deep-layer cyclone over the
northeastern Pacific, currently centered near 44N140W.  The
associated 500-mb low is expected to eject northeastward toward the
BC coast through the period, but decelerate overnight before
weakening offshore on day 2.  The related baroclinic band and
precursory warm-advection conveyor will cross the Pacific Northwest
beginning this afternoon into the overnight hours.  Forecast
soundings show sporadic episodes of elevated CAPE atop the
warm-advection conveyor, and shallow, nearly surface-based CAPE
along and behind the front.  While a lightning strike or two cannot
be ruled out, coverage and duration are expected to be too isolated
and brief for a general-thunder area.

..Edwards.. 01/17/2018