656
ACUS01 KWNS 170050
SWODY1
SPC AC 170048
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0648 PM CST TUE DEC 16 2025
VALID 170100Z - 171200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN THE PACIFIC
NORTHWEST...
..SUMMARY
SPORADIC SEVERE GUSTS MAY ACCOMPANY LOW-TOPPED CONVECTION ACROSS
PARTS OF THE PACIFIC NORTHWEST TONIGHT INTO EARLY WEDNESDAY MORNING.
..PACIFIC NORTHWEST
A VIGOROUS SHORTWAVE TROUGH WILL REACH COASTAL WA BY LATE TONIGHT
AND SPREAD INLAND THROUGH 12Z WEDNESDAY. THIS TROUGH WILL BE
ACCOMPANIED BY AN INTENSE TROPOSPHERIC WIND FIELD, CHARACTERIZED BY
70-90 KTS AT 700 MB, THAT WILL SPREAD ACROSS WA AND OR DURING
06-12Z. A SURFACE CYCLONE WILL MOVE ONSHORE IN BC AND OCCLUDE, AS
DOWNSTREAM LEE CYCLOGENESIS OCCURS OVER SOUTHERN AB.
LOW-TOPPED CONVECTION IS EXPECTED TO INCREASE ALONG THE TRAILING
COLD FRONT ATTENDANT TO THE OCCLUDED CYCLONE, INITIALLY REACHING
COASTAL WA TOWARDS 06Z. SURFACE-BASED BUOYANCY WILL BE SCANT ALONG
THE FRONT, BUT SPORADIC LIGHTNING FLASHES AND OCCASIONAL STRONG TO
SEVERE-CALIBER WIND GUSTS MAY ACCOMPANY THE PASSAGE OF THIS
LOW-TOPPED CONVECTIVE LINE. LOW-TOPPED CONVECTION SHOULD ALSO
INCREASE AHEAD OF THIS LINE OVERNIGHT, AS STRONG LARGE-SCALE ASCENT
COINCIDES WITH PEAK LOW TO MID-LEVEL FLOW. WITH MINIMAL INSTABILITY,
LOW CONFIDENCE EXISTS IN THE DEGREE OF CONVECTIVE ENHANCEMENT BEYOND
THE GRADIENT WINDS. THUS, THE LEVEL 1-MRGL RISK HAS BEEN MAINTAINED
WITH NO CHANGES.
..GRAMS.. 12/17/2025
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