Valid 071630Z – 081200Z
…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF
NORTHERN CALIFORNIA…
…SUMMARY…
A marginal tornado threat exists this afternoon across portions of
northern California.
…Northern California…
No significant changes have been made to the ongoing forecast.
Morning water vapor loop shows a strong upper low around 40N/129W,
with a lead shortwave trough and associated midlevel speed max
rotating toward the coast. Numerous bands and clusters of
precipitation will continue to move onshore over this region today,
but there will also be short-lived periods of
heating/destabilization. Despite near moist-adiabatic lapse rates
aloft, surface dewpoints in the low/mid 50s and temperatures locally
approaching 60 will result in just enough CAPE to pose a risk of a
few rotating storms. Orographically backed low-level winds could
result in a brief tornado or two today in parts of the northern
valley. Overall, the risk seems low and the ongoing MRGL risk
forecast seems to capture it sufficiently.
..Hart/Nauslar.. 12/07/2019
$$