Ahead of the cold front, models are in good agreement with a
strong llj (70-80kt@950mb) developing across eastern coastal
areas late tonight into early Friday morning. As is typical for
this time of year with water temps in the lower 40s, the
challenge is how much of the llj will be able to mix down in a
strongly inverted low-level environment. GFS/NAM have remained
fairly consistent over the last 48 hrs, with GFS indicating a
typically slightly deeper mixed layer, with potential for 50 kt
gusts across LI/SE CT, while NAM more strongly inverted
indicating gust potential of 40 kt. NBM has trended slightly
upward with gust magnitude from 24 hrs ago, with 4.0 indicating
45-50kt gust potential for LI and SE CT, while version 4.1
continuing to showing a 45-55 kt potential for LI/CT. HRRR 10m
wind gust potential, which has show to be skillful (albeit a
little high) indicating potential for 55-60kt gusts for LI and
SE CT as well. SPC HREF indicating high potential for 30kt
sustained winds across LI/SE CT as well (not common),
supporting the strong to damaging wind gust potential.
Based on the model consistency and trends over the last few days,
confidence is high in a strong wind (wind advisory) event tonight
across the entire area, including NYC (45-55mph gusts), with
moderate to high confidence in high winds gusts (55-65mph) for
LI and SE CT under the core of the 75-80 kt llj. The timing for
peak strong to high wind gusts continues to center around 6-12z
Fri.
Despite the strong inversion, based on the slight upward trend on
NBM 4.0 wind gust guidance towards the stronger NBM 4.1 guidance,
the strong signal from CAM guidance, and the anomalous strength of
the llj, will upgrade to a high wind warning for all of LI and
SE CT. Elsewhere will issue a wind advisory for strong wind
gust potential ahead of and immediately behind the cold front,
with highest threat along the coast and higher elevations.