Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
1025 PM EDT Sat Oct 25 2014
a cold front over the Ohio Valley will move through the tri-state
area overnight. Low pressure will then track across the Canadian
Maritimes on Sunday...while high pressure builds east from the
Mississippi Valley. High pressure builds in Monday...then moves
east Tuesday. A cold front passes across the area middle
week...followed by high pressure late in the week. Low pressure
may impact the area early next weekend.
Near term /until 6 am Sunday morning/...
a mainly dry cold frontal passage is on tap tonight as a strong
upper low passes north of the Great Lakes. Gusty SW flow ahead of
the front along the coast. In wake of frontal passage...a period
of moderate to strong cold advection with gusty northwest flow developing
Scattered-broken clouds along and ahead of the front and then Strata cumulus
developing in the northwest zones in the cold advection and with strong
shortwave toward morning. Added isolated sprinkles to forecast
database per hrrr/arw and 18z NAM ahead of cold front and then
again with shortwave. Dry air though the limiting factor.
Temperatures generally on track with lows ranging from the middle 40s
inland...to the lower 50s at the coast. This remains about 5
degrees above normal.
Short term /6 am Sunday morning through Sunday night/...
cyclonic flow and continued cold advection on sun will result in
partly to mostly cloudy skies...with more sun near the coast.
Highs will struggle to get out of the middle and upper 50s. Stayed
just a bit below met/mav MOS guidance...but higher than 2m model
In addition...gusty northwest winds up to 35 miles per hour can be expected as
a strong pressure gradient will reside across the area between low
pressure over the Canadian Maritimes and high pressure building
east into the Tennessee and Ohio valleys.
Skies clear Sun night and winds diminish as high pressure builds in
from the west both aloft and at the surface. Lows will range from the
upper 30s inland to the middle 40s at the coast. This will be close
to seasonable values.
Long term /Monday through Saturday/...
models are in general agreement...although slight differences arise
late in the week.
In the upper levels...ridge builds Monday and passes east by
Tuesday. A shortwave moves across the northern portion of the
country...passes across the Great Lakes region...then crosses the
northeast by Wednesday or Thursday. The flow appears to flatten as
the trough moves to the northeast. Then attention turns toward
central Canada as shortwave energy dives southward on the backside
of the trough...likely carving out a deeper trough late in the week
or into the weekend. Latest runs of the GFS and European model (ecmwf) Show Low
pressure cutting off around the Great Lakes region Friday
night/Saturday. However European model (ecmwf) holds this trough/closed low further
west as GFS is more progressive pivoting the closed low eastward. As
such...the placement of the trough/low differs quite a bit by Saturday.
At the surface...high pressure Monday builds south and east of the
area by Tuesday. A cold front looks to track across the region
sometime Wednesday as surface low lifts well to the north in Canada. The
front should clear the area south and east Thursday as low pressure
upstream approaches. This low moves across the Great Lakes region
Friday. Looking at European model (ecmwf) and GFS...differences arise as the GFS
deepens this parent low much more than European model (ecmwf). European model (ecmwf) develops a
deeper western Atlantic low...due to the differences aloft already
In general...dry weather is expected Monday and Tuesday...with
minimal probability of precipitation with the cold front late Tuesday night or Wednesday. A
few showers may linger just east offshore as the front is slow to
clear the area Wednesday night...but Thursday is dry once again.
Then...unsettled convective weather is expected Friday and
Saturday...with low confidence in forecast details at this time.
Temperatures will be close to normal Monday. Then warm air advection Monday
night and Tuesday should boost temperatures to above normal levels.
Mild readings...slightly above normal...continue Wednesday.
Then temperatures cool somewhat behind the cold front Thursday...with
readings below normal likely Friday and Saturday.
Aviation /02z Sunday through Thursday/...
a strong cold frontal passage tonight...with high pressure
building to the SW on Sunday. VFR but windy conds.
SW winds veer to west between 03-06z tonight with frontal passage...then west-northwest
towards daybreak. Gusty at metropolitan and coastal terminals.
Isolated rain showers activity possible with frontal passage and then
to awards daybreak with upper disturbance.
West-northwest winds 15 to 20 knots with gusts around 30 knots on Sunday.
Winds could peak 20-25 with gusts to 35 knots sun after for metropolitan
terminals. Wind direction expected to range between 300 and 320
magnetic on sun...generally just left of 310 mag for kjfk/kewr and
just right for klga.
Ceilings could become broken for a period Sunday late morning and
during the afternoon.
Winds and gusts gradually subside sun evening.
Outlook for 00z Monday through Thursday.
Sun night-Tue...VFR. Northwest winds g25kt sun evening...highest NYC
metropolitan...subsiding Sun night.
Wednesday...MVFR or lower possible with chance rain showers.
west/SW winds ramp up as the evening progresses to marginal Small Craft Advisory
conditions along and ahead of a cold front approaching from the
west. Post-frontal northwest winds will then increase further with wind
gusts just below gale force on the ocean waters...and around 30
knots elsewhere. Winds and seas will then gradually subside Sun night
as high pressure continues to build in from the west.
Gusty winds diminish Monday as high pressure approaches and passes
just to the south. Winds shift around to the SW/S ahead of a cold
front Tuesday...and will increase once again. The winds shift as the
cold front moves across the waters Wednesday...then diminish as weak
high pressure builds Thursday.
Rough seas subside Monday. Expect ocean seas to remain below Small Craft Advisory
thresholds Monday night and Tuesday. However...seas build once again
as southerly flow increases Tuesday night and Wednesday. These seas
will gradually subside Wednesday night and Thursday as the winds
shift and diminish.
no significant widespread precipitation expected through the
middle of the week.
Marine...Small Craft Advisory until 6 am EDT Monday for anz330-335-338-
long term...precipitable water