Weather with Bill Evans
Good Day On This Friday April 16, 2021
Low pressure will meander along the southern New England coast
today, then slowly move east into the Atlantic tonight through
Sunday. Weak high pressure will build into the area Saturday and
remain into early next week. A cold front approaches and moves
across going into Wednesday, followed by another high pressure
area for next Thursday.
A closed upper low tracks across the region through this
afternoon as surface low pressure moves along the southern New
England coast. And with an occluded front across southern New
England providing lift the steadiest precipitation remains
across southeastern Connecticut. The precipitation was mainly
light rain, however, with low level colder air wrapping into the
west side of the low the precipitation was changing over to
light snow. The snow will remain light with no deep cold air and
no snow growth in the ideal zone. And with temperatures near to
above freezing, little accumulation is expected, less than an
inch. And the higher amounts will be across the higher
elevations. Areas outside of the best lift will see light rain,
more scattered and showery in nature. A chilly airmass remains
with temperatures as much as 10 degrees below seasonal normals.
This evening with upper low and surface low begin to slowly
track east into the western Atlantic. As this happens the
precipitation gradually ends across the area, possibly
transitioning back to light snow across southeastern
Connecticut before ending. Height slowly rise through tonight
and into Saturday as deep cyclonic flow remains. There is some
low level moisture and a few sprinkle cannot be completely ruled
out across the lower Hudson Valley Saturday afternoon as the
cyclonic flow remains. Temperature modify Saturday as the core
of the cold air moves east with the nearly stacked low.
Weak ridging begins to build to the west Saturday night as the
closed upper low continues to slowly track east of the New
England coast.
With the upper and lower level lows moving farther eastward
into the Atlantic and closer to the Canadian Maritimes for the
remainder of this weekend, weak high pressure at the surface
will start to build in. The weakening pressure gradient will
allow for winds to become lighter Saturday night through Sunday
night. Aloft, though, the flow transitions to more zonal with
periodic shortwaves with positive vorticity advection moving
across. This will continue into early next week with a stronger
shortwave moving across Monday into Monday night. The rest of
the weekend is still expected to be mainly dry. The forecast has
a slight chance of rain showers Sunday afternoon into early
Sunday evening with a greater chance for rain showers Monday
afternoon into early Monday evening with that stronger shortwave
moving across. Diurnal instability with daytime warming will
help initiate the shower activity both days.
Some brief ridging aloft takes place thereafter Tuesday into
Tuesday night before a deeper trough and surface cold front
approach Wednesday into Wednesday night. Outside of a possible
shower Tuesday afternoon into Tuesday night, mainly dry
conditions are expected. A greater chance for rain showers is in
the forecast for Wednesday with the cold front expected to move
across. GFS model shows some weak surfaced based instability so
there could be a rumble of thunder but left out of forecast for
now due to the event being almost a week away and higher
uncertainty.
Temperatures are forecast to be near normal values for the max
temperatures Sunday (upper 50s to lower 60s), followed by
values getting more above normal for Monday (mainly low to mid
60s) and Tuesday (mainly low to upper 60s). A return to near
normal highs is forecast for Wednesday followed by slightly
below normal highs for next Thursday.
.MARINE...
Wind speeds and gusts across the ocean waters early this
morning have been a few knots lower than forecast, and gusts
wind speeds have been adjusted through early this morning.
Low pressure will be moving along the southern New England
coast today and with an increasing pressure gradient force,
especially across the eastern portion of the forecast area, wind
gusts will be increasing to 25 to 30 kt across the forecast
waters. This will continue into late tonight as the low begins
to track east this evening. A SCA was now posted for the western
Long Island Sound, New York Harbor, and the southern bays until
late tonight, and remaining on the other forecast waters. With
gusty winds to SCA levels now expected through tonight on the
ocean waters, and elevated seas into Saturday, the SCA was
extended through tonight west of Moriches Inlet, and through
midday Saturday east of Moriches Inlet.
After midday Saturday mainly below SCA level wind gusts are
forecast through Tuesday night. Another exception is Tuesday
into Tuesday night with an increase in pressure gradient ahead
of the next approaching cold front with some 25 kt gusts
possible. Seas are forecast to remain below 5 feet midday
Saturday through Tuesday night.
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