Scientific Forecaster Discussion
Area forecast discussion
National Weather Service New York New York
348 PM EDT Sat Oct 25 2014
a cold front over the Ohio Valley late this afternoon will move
through the tri-state area tonight. 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 dry cold frontal passage is on tap late tonight as a strong
upper low passes north of the Great Lakes. This will result in a
period of moderate to strong cold advection and gusty northwest flow
developing toward daybreak. There may be a period of clouds as
well along and ahead of the front and then Strata cumulus developing
in the northwest zones in the cold advection toward morning.
Lows will range 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 Friday/...
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 /19z Saturday through Thursday/...
brief high pressure this afternoon followed by a dry cold frontal passage
tonight into Sunday. VFR conditions expected.
Winds will generally be northwest 10-15 knots with some gusts middle to late
afternoon to around 20 knots while backing to W-WSW. Winds remain
around 10 knots tonight. On Sunday...winds will be from the northwest
with speeds into the upper teens to near 20 knots. Expect gusts into
the upper 20 knots to near 30 knots.
Ceilings could become broken for a period Sunday late morning and
during the afternoon.
High confidence category forecast but moderate confidence wind
forecast. Uncertainty with end time of gusts which could linger a
few hours into the evening.
Outlook for 18z Sunday through Thursday.
Sun-Tue...VFR. Northwest winds g25-30kt on sun-sun evening...highest NYC metropolitan.
Wednesday...MVFR or lower possible with chance rain showers.
west/SW winds ramp up this evening 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 25 to 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 from 6 PM this evening to 6 am EDT Monday
long term...precipitable water