Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 260750

Area Forecast Discussion
National Weather Service New York NY
350 AM EDT THU MAY 26 2016

High pressure will be in place through Friday, and the region will
be under the influence of a westward extension of the Bermuda
High for the weekend. A cold front approaches from the west
Monday, then pushes through the area Monday night. This front then
stalls out near or just to the south of the area through Wednesday
as high pressure builds to the north.


Dry weather expected this morning with deep-layered ridging. A
shortwave embedded within ridge approaches late in the day, and with
increasing mid-level moisture there could be a shower or
thunderstorm by late, primarily over the NW zones where CAPES will
be higher. Limiting factors however will be some capping aloft with
relatively stable mid-level lapse rates.

High temperatures will be well above normal as they were yesterday.
Thinking is that most spots will be a little cooler than yesterday,
more so at the coastal areas as sea breezes will begin earlier this
time around and affect more areas. Additionally, 850 mb temps are
forecast to be about a degree Celsius cooler.

There is a moderate risk of rip current development at the
Atlantic beaches today into this evening.


500 mb shortwave enters tonight, but weakens as it moves across the
region. Loss of instability will help keep any showers/storms iso to

850-700 mb shortwave slowly moves through the cwa during Friday.
Moisture depth and lift will be greater during the morning, but
CAPES will be higher in the afternoon. Will therefore go no higher
than chc pops for now. High temps still well above normal with 850
mb temps climbing back up to 15-16C. Amount of cloud cover and sea
breezes should offset the max temp potential somewhat, but in
general, going with highs a little cooler than today in most spots,
primarily due to more cloud cover.


A westward extension of the Mid-Atlantic Ocean based sub-tropical
ridge builds in Friday night-Saturday...then retreats back to the
southeast Saturday night and Sunday. The result will be continued
very warm and humid conditions across the region. There will also be
some mainly diurnal isolated-scattered showers and thunderstorms
from Friday evening through Sunday as well.

Temperatures during this time frame were based on a blend of all
available guidance, with NAM 2-meter temperatures blended in Friday
night-Saturday night, and a mix down from 975-850 hPa, per BUFKIT
soundings, blended in for highs on Saturday. Lows will run around 10
degrees above normal both Friday and Saturday night. Highs Saturday
and Sunday should run around 10-15 degrees above normal.

The forecast for Sunday night-Wednesday is very much dependent on
the interaction between a northern stream shortwave that is forecast
to move across the Great Lakes and a possible closed low near the
mid-Atlantic Coast. There is quite a spread in model solutions, with
the GFS showing the most interaction between these two systems and
the ECMWF the least. The CMC-Global is somewhat in between these two
solutions, but trends closer to the ECMWF with time. It should be
noted that the ECMWF and GFS basically flipped solutions from the
12z to the 00z runs. The result is a low confidence forecast from
Sunday night-Wednesday.

For now will run with pops increasing to chance throughout Sunday
night for showers and thunderstorms, continuing on Monday, then
tapering off Monday night. Given uncertainties in how quickly the
airmass changes on Tuesday, have included some diurnal convection
then, however, if the ECMWF/CMC are correct, Tuesday could end up
dry. Given the overall uncertainty then maintain mainly slight
chance pops for Tuesday night and Wednesday.

For temperatures Sunday night-Wednesday, the Superblend was used,
with above normal temperatures forecast, but not quite as warm
as this weekend.


VFR forecast.

High pressure builds to the south overnight and

Light west/southwest expected overnight.

Light winds in the morning become south around 10 kt. Sea breezes
are expected by afternoon, sooner across CT terminals.

KLGA may be affected by a sound breeze which may make winds turn
to an east or southeast direction between 12Z and 15Z. However,
there is a low chance of this happening.

.OUTLOOK FOR 00Z Friday through Monday...
.Thursday night through Friday morning...Mainly VFR but sub-VFR
possible in showers/evening thunderstorms.
.Friday through Friday night...Mainly VFR, but sub-VFR possible in
isolated showers and evening thunderstorms.
.Saturday...Mainly VFR. Isolated showers and thunderstorms north
of NYC/Long Island.
.Sunday...Sub-VFR possible in afternoon showers and thunderstorms.
.Monday...Sub-VFR possible in showers and thunderstorms.


With the pressure gradient overall remaining rather weak...seas and
wind gusts will stay below SCA criteria through Friday.

A weak to moderate pressure gradient over the region Friday Night
through Monday will keep winds to 15 kt or less over the waters
around Long Island. With no significant swells forecast during this
time frame, seas will remain below Small Craft levels as well.


No significant widespread precipitation expected through Thursday
night. Local minor flood impacts from heavier showers/tstms are
possible on Friday.

There is the potential for locally heavy rainfall, for areas mainly
N/W of NYC Saturday and Sunday, with a higher chance of a more
widespread moderate to heavy rainfall from Sunday night into Monday,
and possibly lingering farther into next week. For this weekend, the
main threat is ponding of water on roadways, with a low risk of
minor flooding of urban and poor drainage areas (once again the main
threat this weekend will be to the N/W of NYC). At this time, there
is too much uncertainty to specify any threat for early next week,
other than to note the situation bears watching.




LONG TERM...Maloit
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