Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
359 PM EDT Sat Aug 30 2014
high pressure moves well to the east through Sunday. Low pressure
tracks across the Great Lakes and into eastern Canada...sending a
low pressure trough across the area late Sunday. A cold front
weakens and eventually dissipates within the region on Monday.
This will leave a weak pressure gradient. Another cold front moves
through Tuesday night with high pressure then building in from the
south and west through Thursday. The high moves offshore Friday
with another cold front approaching into the beginning of next
Near term /until 6 am Sunday morning/...
aloft...large ridge remains anchored southeast of the region as a
trough moves across the Great Lakes region tonight.
Surface high pressure sits southeast of the region tonight.
Plenty of SC due to increased moisture underneath inversion will
result in at least partly cloudy conditions. Middle and high level
clouds should also increase from the west.
As such...plenty of clouds...warm and increasingly muggy conditions
are forecast overnight. Dew point increase per MOS as south flow
persists. Low temperatures in the 60s per MOS blend followed.
There is a moderate risk of rip currents into this evening.
Short term /6 am Sunday morning through Sunday night/...
deep southwest flow through this time frame as shortwave moves well
to the north...with ridge anchored over the western Atlantic.
Warm and muggy conditions will prevail. Plenty of clouds
expected...along with an increasing chance for showers/tstms.
Moderate instability is expected by afternoon Sunday...and
precipitable waters increase to 2 inches...or close to 200
percent above normal late in the day and into the evening.
Marginal to moderate shear is present...with ki right around 35c.
Expect scattered to numerous...although will keep probability
wording...showers and thunderstorms. Some of which will produce heavy
downpours. Best timing is late afternoon western zones...and through
the evening/overnight coastal and eastern zones.
Models continue to vary with regard to heavier shower/thunderstorm
location...due to the scattered nature of the activity and varying
placements of embedded middle level shortwaves. Surface trough approaching
to the west should trigger activity.
After collab with surrounding offices...will not issue a Flash Flood
Watch at this time. The threat will be urban...with perhaps flashier
streams susceptible to flash flooding. Otherwise...County guidance
likely too high outside of metropolitan.
Warm temperatures in the 80s Sunday...with warm upper 60s to 70s Sunday
night lows. Followed a MOS blend...which included ecs numbers.
Long term /Monday through Saturday/...
the dominant pattern in the long term is that of ridging on average.
On a large scale...ridge is apparent on the model height fields
aloft from Quebec to the mid-Atlantic. A relatively stronger upper
level trough passes north of the region late Tuesday into early
Wednesday with some more height falls and a transition to zonal
flow. Ridging resumes thereafter with the large ridge across the
southern U.S. Pushing north from Wednesday through Friday.
At the surface...a cold front moving in from the west dissipates
within the region without much upper level support on Monday. A weak
pressure gradient is left in its place without a strong presence of
high pressure. The jet stream will be lifting north away from the
region helping explain the lack of support aloft. The jet pushes
back south Tuesday night into early Wednesday...so this will help
push another cold front through the region. This will transition
winds to more of a northerly for Wednesday. The flow weakens
Thursday allowing for sea breezes to develop as high pressure builds
in from the south and west. The high moves offshore Friday into the
next weekend. Yet another cold front approaches into the beginning
of next weekend.
Outside of Wednesday...a general south to southwest flow dominates
next week. This will result in temperatures well above seasonal
averages for this time of year. The jet stream overall keeps to the
north of the region.
In terms of weather...showers and thunderstorms on Monday with the
instability and remnant frontal boundary across the region. Chances
decreasing by late in the day and into Monday night. Estimating
these to be more of the pulse variety with the lack of upper level
support. Bulk shear 0-6km mostly 20-25 knots with cape being the
greater driver for convection. Another chance of showers and
thunderstorms from northwest to southeast Tuesday into Tuesday night
with a little more shear to work with. Mainly dry thereafter.
Aviation /20z Saturday through Thursday/...
high pressure off the New England coast will move out to sea through
tonight as a trough of low pressure approaches from the west.
VFR with broken cumulus today. Southerly winds around 10 knots...occasional gusts 16-19kt
for the city terminals and kisp this afternoon. Winds diminish after
MVFR conds late night/early am sun...returning to VFR in the late
morning/early afternoon. Scattered rain showers/thunderstorms starting middle-late afternoon mainly
from city terminals and points N/W.
Outlook for 18z sun through Thursday...
sun-Monday night...multiple rounds of -shra/thunderstorms and occasional MVFR.
southerly winds persists tonight as high pressure drifts further to
The southerly winds increase ahead of a surface trough later Sunday
into Sunday evening. Expect winds to remain just below 25 kts on
the waters...so will not issue a Small Craft Advisory at this time per surrounding
office collab. Seas build in response to these increasing
winds...and may come close to 5 feet over the ocean waters late
Sunday and into Sunday night.
Overall...the pressure gradient remains weak in the long term period
of Monday through Thursday. Seas will be on a downward trend early
Monday with a cold front dissipating within the region. Conditions
are expected to remain below Small Craft Advisory on the waters through the long term
deep moisture in place with trough approaching Sunday and into the
region Sunday night...so any showers and thunderstorms will be
capable of producing locally heavy downpours. Localized flooding
threat will remain which would vary from minor and poor drainage
to possibly flash flooding.
Heavy rain potential with any showers or thunderstorms will remain
as precipitable waters remain around 2 inches Monday. This will pose
a flooding threat varying from possible minor and poor drainage
flooding to some possible flash flooding.
near term...precipitable water
short term...precipitable water