Scientific Forecaster Discussion
fxus61 kokx 180227
Area forecast discussion
National Weather Service New York New York
1027 PM EDT Tue Sep 17 2019
high pressure will dominate the weather pattern through the
weekend. A cold front may cross the region early next week.
Near term /through Wednesday/...
the forecast remains on track. Surface high pressure will
remain north of the region tonight. Meanwhile, an upper level
trough will remain northeast of the area. The combination of an
increasing northeast flow and a shortwave rounding the base of
the trough will result in an increase in cloud cover late
tonight through Wednesday morning. Tonight, will start off
mostly clear skies but skies become partly to mostly cloudy
towards daybreak and continue through much of the morning and
into the afternoon, with some clearing expected late. Despite
the partly to mostly cloudy skies, conditions will remain dry.
Temperatures may be tricky tonight especially across the
eastern half of the area, as initially clear skies will allow
for some radiational cooling before clouds increase. For now,
think the thicker cloud cover will move in late enough that
temperatures will be able to fall off quickly this evening
before remaining nearly steady towards daybreak. This will
result in lows ranging from the mid to upper 40s in typically
cooler outlying locations to around 60 in New York City.
Temperatures on Wednesday will then remain several degrees
below normal with a good deal of cloud cover and persistent
northeast flow. Highs will be in the 60s and lower 70s.
There is a high risk of rip currents at Atlantic Ocean beaches
on Wednesday due to long period swells from distant Hurricane
Short term /Wednesday night/...
high pressure near the region Wednesday night will result in
clearing skies and dry conditions. Lows Wednesday night will
fall into the 40s and 50s.
Long term /Thursday through Tuesday/...
psuedo-Omega blocked pattern late week with the region on the
northeast side of eastern US upper ridging in between deep
western US troughing and western Atlantic troughing interacting
with Hurricane Humberto. This blocking eventually breaks down,
with upper ridging sliding eastward into the area this weekend,
as Humberto and western Atlantic troughing gradually shear NE.
Western US troughing gradually slides northeast towards the
region Monday and through Tuesday. At the surface, Canadian high
pressure builds overhead Thursday, with sprawling high pressure
establishing itself east of the Mississippi River for late week
into the start of the weekend. A weak backdoor cold front does
appear to slide through the region Saturday, with high pressure
slowly sliding east Sunday into Monday.
Tranquil and moderating temps to near seasonable levels Thu and
then above normal Fri (mid to upper 70s), as center of high
pressure gradually slides to the south of the region. Potential
for good radiational cooling conds Thu night, with lows in the
40s across outlying areas. A weak cold front move through Friday
night, with north flow early, giving way to return flow Saturday
night into Monday ahead of approaching shortwave/cold front.
Temps Saturday into Monday should rise well above seasonable
levels(lower to mid 80s), with increasing humidity levels Sunday
Next chance for measurable precip appears to come late Monday
into Monday night with approach of next trough, with better
model agreement on approaching shortwave energy on Monday and
slide through Tuesday.
NHC track forecasts for Humberto have been consistent in slowly
tracking it east and then northeast through the next 5 days,
well out to sea. The likely indirect impacts will be dangerous
rip/longshore currents and rough surf at Atlantic Ocean beaches
starting Wednesday as long period swells and wind waves begin to
increase. Potential for high surf (5-9ft)late Thu into Fri as
the most energetic E/se swells arrive from Humberto. Beach
flooding and erosion issues likely during the times of high tide
Wed thru Fri with E to W sweep, but potential for dune erosion
and localized washovers looks to be low. Refer to the National
Hurricane Center for official forecast information on Humberto.
Aviation /03z Wednesday through Sunday/...
high pressure continues to build in from the north through
Wednesday, while hurricane huberto tracks well offshore over the
western Atlantic. This will keep the area under a prolonged
period of north to northeast flow.
Winds will be generally NE through the forecast period. Winds
will be under 10 kt through the overnight, then the NE flow
increases to 10 to 15 kt Wednesday morning, closer to 15 kt
along the coast. Gusts 15 to 20 kt develop Wednesday morning
with occasional higher gusts possible, especially in the
Outlook for 00z Thursday through Sunday...
Wednesday night through Sunday...VFR.
seas will build tonight approaching 5-7 ft after midnight and
continue through Wednesday night in response to long period
swells from distant Hurricane Humberto. In addition, wind gusts
could approach Small Craft Advisory criteria for a period Wednesday afternoon
east of Moriches Inlet as the pressure gradient tightens between
Hurricane Humberto and high pressure building south out of
Winds Thursday through Sunday will remain below Small Craft Advisory. Rough seas
will continue Thu into Fri as 7 to 9 ft long period swells from
Humberto build in. Seas gradually subside below Small Craft Advisory Saturday
into Saturday night.
no significant hydrologic impacts through the weekend.
NYC National oceanic and atmospheric administration weather radio station kwo35 (162.55 mhz) remains off
New York...high rip current risk from 6 am EDT Wednesday through
Wednesday evening for nyz075-080-081-178-179.
Marine...Small Craft Advisory until 6 PM EDT Thursday for anz350-353-
short term...British Columbia