Area Forecast Discussion
Issued by NWS Upton, NY-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KOKX 210843
Area Forecast Discussion
National Weather Service New York NY
443 AM EDT Tue Mar 21 2017
A weak cold front will move across this morning, followed by a
stronger cold front tonight. High pressure moves into the Great
Lakes Wednesday and then closer to the local region Wednesday
night. High pressure builds Thursday, and passes to the east
Friday. A cold front sags south toward the area this weekend.
Low pressure approaches the region early next week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The weak cold front is difficult to discern with an overall
weak pressure gradient across the region. The colder
temperatures aloft are apparent from model fields to move in
The frontal passage is mainly dry with any precipitation being
light rain confined towards the SW portions of the region.
Behind this weak front, a more westerly flow develops and will
allow for vertical daytime mixing. This will have less marine
Very mild temperatures are expected. Used a blend of bias
corrected ARW and NMM with some further manual adjustments. The
range for max temperatures will be well into the 50s, higher 50s
within the NYC Metro Area.
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
A stronger cold front will be moving across tonight. The overall
westerly flow through the atmosphere will make for a dry frontal
passage. However, strong deformation is evident in the model
fields in the low to mid levels behind this front. Strong cold
air advection will occur. Northwest gusty flow eventually
develops late tonight and through Wednesday and Wednesday
evening. The flow backs from NW in the lower levels to W in the
mid levels, presenting backing of winds.
Much colder temperatures will result. Upper 20s to lower 30s are
expected for lows tonight while highs Wed will be about 20-25
degrees colder than the previous day. Even colder lows Wed
night, with a general range of 8 to 20 degrees.
.LONG TERM /THURSDAY THROUGH MONDAY/...
Dry weather Thursday, then unsettled through the weekend and into
early next week.
High pressure/ridge provides plenty of sunshine Thursday. Then upper
shortwave approaches Friday as ridge flattens across the northeast.
Further west, split upper flow with ridge located in southern
Canada, and mid west trough sets the stage for sfc high pressure
building to the north from central Canada, with a frontal boundary
approaching from the NW. Some light precipitation may ride along
this frontal boundary Friday, Friday night and into Saturday, as the
high builds to the north. The front sags south toward the area
Saturday per GGem, GFS and EC. Spotty rain possible with the front,
although lift and moisture is lacking for widespread coverage.
The trough makes eastward progress, with sfc low approaching the
area Sunday into Monday. Increasing moisture and lift will likely
result in increasing coverage for rain, or rain/snow mix interior
during that time.
Cold temperatures Thursday are expected as the Canadian high
pressure builds. Then temperatures warm closer to, but just short of
normal Friday as the high passes and southerly flow sets up.
Temperatures over the weekend will depend on exact placement of
backdoor front. Saturday readings may rise to above normal levels
ahead of the front, but likely settle back below normal thereafter
as northeasterly flow sets up, assuming front does pass just to the
south, which appears likely at this time.
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --High pressure remains over the region tonight. A weak cold front
will move through Tuesday morning, bringing only additional
clouds. Light northwest winds tonight, generally 10 KTS or less.
Winds will increase during the mid to late morning on Tuesday,
becoming more westerly by afternoon. Clouds become more
scattered behind the passing front.
VFR through the TAF period.
...NY Metro Enhanced Aviation Weather Support...
Detailed information, including hourly TAF wind component forecasts,
can be found at: http://www.weather.gov/zny/n90
KJFK TAF Comments: No unscheduled amendments expected.
KLGA TAF Comments: No unscheduled amendments expected.
KEWR TAF 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 TAF Comments: No unscheduled amendments expected.
KHPN TAF Comments: No unscheduled amendments expected.
KISP TAF Comments: No unscheduled amendments expected.
.OUTLOOK FOR 00z TUESDAY THROUGH Saturday...
Tuesday night-Thursday..VFR. NW gusts 20-25 kt possible on
.Friday...Chance of sub-VFR cigs.
-- End Changed Discussion --
Sub SCA today and through much of tonight. Then gales develop as
a result of cold air advection over relatively warmer sea
surface temperatures Wednesday into Wednesday evening.
Winds will diminish Thursday as high pressure builds. Seas subside
during this time. By Friday, the center of the high passes to the
east, and increasing southerly flow will result in building seas.
A cold front approaches the waters from the north Saturday. Winds
begin to diminish as the front nears, allowing seas to subside once
No hydrologic problems expected through this week.
MARINE...Gale Warning from 6 AM Wednesday to 2 AM EDT Thursday for