SPC MD 78

MD 0078 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR IMMEDIATE COASTAL REGIONS OF SOUTHERN MARIN...SAN FRANCISCO...AND SAN MATEO COUNTIES

Mesoscale Discussion 0078
NWS Storm Prediction Center Norman OK
0544 AM CST Fri Jan 20 2017

Areas affected...Immediate coastal regions of southern Marin...San
Francisco...and San Mateo counties

Concerning...Severe potential...Watch unlikely 

Valid 201144Z - 201245Z

Probability of Watch Issuance...5 percent

SUMMARY...Locally strong wind gusts (around 40-50 kt) will be
possible as an eastward-moving line of storms reaches the coastal
areas of southern Marin, San Francisco, and San Mateo counties by
12Z.

DISCUSSION...At 1125Z, radar imagery continued to show a fast-moving
line of storms (speed close to 50 kt) approaching the Pacific
coastal areas of southern Marin, San Francisco, and San Mateo
counties, with this activity expected to reach the coast by 12Z.
Area WSR-88D VWP data indicated south-southeasterly low-level winds
of 40-50 kt.  Wind gusts associated with the line of storms could
reach 40-50 kt at the surface, given momentum transfer in the
downdrafts.  The threat for the locally strong/damaging wind gusts
is expected to be confined to the coastal areas, since a more stable
environment inland with surface temperatures in the upper 40s should
support a diminishing trend in storm intensity.

..Peters/Thompson.. 01/20/2017

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MTR...

LAT...LON   37852256 37852253 37752249 37642246 37542246 37432240
            37392239 37362244 37482252 37582256 37752256 37822259
            37852256 

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