406
ACUS01 KWNS 250538
SWODY1
SPC AC 250537
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1137 PM CST WED DEC 24 2025
VALID 251200Z - 261200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR MUCH OF THE
CALIFORNIA COAST AND PORTIONS OF THE CENTRAL VALLEY...
..SUMMARY
THUNDERSTORMS WITH POTENTIAL TO PRODUCE MARGINALLY SEVERE WIND GUSTS
AND PERHAPS A BRIEF TORNADO WILL BE POSSIBLE ON THURSDAY ALONG MUCH
OF THE CALIFORNIA COAST AND PORTIONS OF THE CENTRAL VALLEY.
.. SYNOPSIS
A HIGHLY AMPLIFIED PATTERN WILL PERSIST ACROSS THE US AS A DEEP
TROUGH OVER THE EASTERN PACIFIC IS MAINTAINED AND A RIDGE BUILDS
OVER THE CENTRAL US. A SERIES OF EMBEDDED SHORTWAVE TROUGHS WITHIN
THE EASTERN PACIFIC TROUGH WILL IMPACT THE WEST COAST ON CHRISTMAS
AND CHRISTMAS NIGHT.
.. CALIFORNIA
THE FIRST OF THESE SHORTWAVE TROUGHS WILL BE MOVING ACROSS THE
REGION AT THE START OF THE FORECAST PERIOD, BRINGING WITH IT A BAND
OF STRONGLY FORCED CONVECTION, LIKELY LOCATED ACROSS PORTIONS OF THE
CENTRAL COAST OF CALIFORNIA INTO THE CENTRAL VALLEY. AS THE
SHORTWAVE TROUGH TAKES ON AN INCREASINGLY NEGATIVE TILT, A 50-60
KNOT SOUTHERLY LOW-LEVEL JET WILL BE MAINTAINED ALLOWING FOR
SUFFICIENT LOW-LEVEL THETA-E ADVECTION TO SUPPORT A MODEST 100-300
J/KG OF SURFACE-BASED CAPE. AS THE CONVECTIVE BAND INTERACTS WITH
THIS STRONG LOW-LEVEL KINEMATIC FIELD, GUSTY/DAMAGING CONVECTIVE
WINDS MAY BE REALIZED AT THE SURFACE, PARTICULARLY WITH THE STRONGER
CONVECTIVE ELEMENTS. FORECAST LOW-LEVEL HODOGRAPHS AHEAD OF THIS
CONVECTIVE LINE FEATURE SUFFICIENT LOW-LEVEL CURVATURE TO SUPPORT A
BRIEF TORNADO SHOULD ANY CONVECTIVE ELEMENT REALIZE TRUE
SURFACE-BASED BUOYANCY. AS THE MORNING PROGRESSES, THE
AFOREMENTIONED SHORTWAVE TROUGH WILL LIFT NORTH THEN NORTHWEST
WITHIN THE BROADER CYCLONIC FLOW ACROSS THE EASTERN PACIFIC WHEREAS
THE BAND OF CONVECTION SLOWLY ADVANCES SOUTH AND EAST. BY MIDDAY,
THE LOW-LEVEL WIND FIELDS SHOULD WEAKEN SUFFICIENTLY IN RESPONSE TO
THE DEPARTING SHORTWAVE TROUGH TO REDUCE THE POTENTIAL OF DAMAGING
WINDS/TORNADOES ACROSS FAR SOUTHERN CALIFORNIA.
BY MID-AFTERNOON, ANOTHER SHORTWAVE TROUGH WILL APPROACH THE CENTRAL
AND NORTHERN CALIFORNIA COAST. IN RESPONSE, THE LOW-LEVEL WIND
FIELDS WILL ONCE AGAIN STRENGTHEN, ALBEIT PERHAPS NOT TO THE EXTENT
AS WITH THE MORNING WAVE. ANOTHER BAND OR BANDS OF STRONGLY FORCED
CONVECTION ARE EXPECTED TO DEVELOP ACROSS THE EASTERN PACIFIC AND
APPROACH COASTAL AREAS OF CENTRAL CALIFORNIA AFTER 00Z (4 PM PT). AS
WAS THE CASE WITH THE MORNING CONVECTION, THE STRONGEST CONVECTIVE
ELEMENTS MAY BE CAPABLE OF MIXING DOWN THE STRONGER WINDS ALOFT
RESULTING IN THE POTENTIAL FOR ISOLATED STRONG THUNDERSTORM WINDS.
..MARSH/SQUITIERI.. 12/25/2025
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