Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
612 am EDT Monday Apr 27 2015
a series of lows near the Canadian Maritimes will drop south and
east of Nova Scotia the next couple of days...consolidating into
one area of low pressure well east of New England by Wednesday.
At the same time...weakening high pressure over the middle section
of the country slowly builds in from the west. High pressure will
remain near the region on Wednesday...then lift to the north on
Thursday. Meanwhile...low pressure over the Gulf Coast states will
track to the middle Atlantic coast by Thursday and continue northeast
into the Atlantic through the end of the week. A few upper level
disturbances may impact the area next weekend.
Near term /until 6 PM this evening/...
minor adjustments based on initial conditions.
A west to east oriented upper trough...stretching from the Great
Lakes to east of the Canadian Maritimes...will pivot south across
the NE today. This combined with cyclonic flow will result in
mostly cloudy skies and a chance of showers...primarily during the
afternoon hours. Instability is marginal and elevated. Have
removed the mention of thunder.
Daytime highs will top out in the upper 50s to lowers 60s.
Preferred cooler mav MOS.
A gusty northwest flow will develop by late morning due to a tightening
pressure gradient between low pressure off the New England coast
and high pressure over the middle section of the country.
Short term /6 PM this evening through 6 PM Tuesday/...
a few showers may linger into early this evening before
conditions dry out and skies begin to clear. Upper trough axis
will pass to the south and east. Lows will be in the 40s...nearly
Instability clouds will likely redevelop Tuesday after with a cyclonic
flow. Still expecting more sun than clouds. Gusty northwest winds up to
20 miles per hour will continue. Temperatures should be a few degrees warmer than
Monday...with highs in the lower to upper 60s...which is also close
to being seasonable.
Long term /Tuesday night through Sunday/...
some model differences in the long term...so wont make too many
changes with low confidence forecast. High pressure builds over the
region for Tuesday night through Wednesday night. Expect dry weather
for this time period.
Models start to differ during the Thursday-Friday night time frame
with an area of low pressure moving off the middle Atlantic coast
and moving to the northeast. The 00z GFS has a solution with the low
off the New Jersey coast and then moving east...bringing a period of rain to
the region from late Thursday through Saturday. The 00z European model (ecmwf)
however brings the low off the North Carolina/Virginia coast and
moves the low east...keeping the region mostly dry. Will continue to
follow the European model (ecmwf) solution which has had better run to run continuity
over the past few days than the GFS. Will keep low chance probability of precipitation in the
forecast Thursday night through Friday night to account for the GFS
trends...but this is a low confidence forecast.
A few upper level shortwaves may move across the region next
weekend...although it looks like only light quantitative precipitation forecast would impact the
Temperatures will be near normal levels through the period.
Aviation /10z Monday through Friday/...
the region will be between high pressure over the Midwest and low
pressure tracking southward from the Maritimes through tonight.
Mainly VFR through the taf period with ceilings around 5-7k feet. Some
isolated-scattered showers possible after 16z...but coverage too low and timing
too uncertain to maintain in the tafs. Brief MVFR possible in any
West-northwest winds will increase through the day. Direction will be close to
310 true at the city terminals until the flow veers a little to the
northwest this evening.
... Metropolitan enhanced aviation weather support...
Detailed information...including hourly taf wind component forecasts can
be found at: http:/www.Erh.NOAA.Gov/zny/n90 (lower case)
Kjfk fcster comments: flow may be left of 310 true most of today.
Klga fcster comments: flow may be right of 310 true most of
Kewr fcster comments: no unscheduled amendments expected.
The afternoon kewr haze potential forecast is green...which implies
slant range visibility 7sm or greater outside of cloud.
Kteb fcster comments: no unscheduled amendments expected.
Khpn fcster comments: no unscheduled amendments expected.
Kisp fcster comments: no unscheduled amendments expected.
Outlook for 06z Tuesday through Friday...
Monday night...VFR with northwest flow.
Tuesday...VFR with north flow.
Wednesday...VFR with light and vrb flow becoming SW.
Thursday...mainly VFR. Low probability for -shra. Winds becoming east-northeast.
Friday...coastal storm possible with NE flow and rain.
a series of lows near the Canadian Maritimes will consolidate
into one main low well east of New England by Wednesday. At the same
time...weakening high pressure builds east from the middle section of
the country. This will keep the waters under a west-northwest flow today and
tonight...and northerly on Tuesday. There looks to be a period of marginal
Small Craft Advisory gusts late tonight on the ocean waters...which should
diminish on Tuesday.
Sub-Small Craft Advisory conditions expected Tuesday night through Thursday.
Depending on the track of a coastal storm at the end of the
week....sca flags may be needed Thursday night through the end of
significant precipitation is not expected through Wednesday. A
coastal low at the end of the week will have to be watched for a
potential widespread rainfall event. There are model discrepancies
at this time that vary significantly with the track.
Marine...Small Craft Advisory from 6 PM this evening to 6 am EDT
Tuesday for anz350-353-355.
long term...British Columbia