Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 030946 AFDOKX Area Forecast Discussion National Weather Service New York NY 446 AM EST Sat Dec 3 2016 .SYNOPSIS...
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High pressure builds towards the area this weekend, giving way to a weak disturbance Sunday night into Monday. High pressure builds in late Monday into Tuesday. A frontal system will approach for the middle of next week.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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A gusty NW flow will develop after sunrise this morning mostly due to a tight pressure gradient between a strong area of low pressure departing into the Northern Atlantic ocean and strong high pressure building from the west...but there will also be some weak CAA as well. Areas N and W of NYC already have BKN to OVC cloud cover from lake effect streamers...however stratocu should decrease early this morning and then return late this morning and afternoon as low level instability increases. Dry weather will prevail with any lake effect remaining to the north and west. Highs will be in the mid to upper 40s in most locations...however with the wind it will feel a bit chilly...ranging from mid 30s inland to lower 40s at the coast.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
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Deep layered ridging builds towards the area tonight and OHD on Sunday resulting in dry conditions. Gusts should diminish shortly after sunset this eve along with clearing skies. Near the coast...there may be enough wind to keep low temps around the freezing mark...however little wind well inland will allow temps to drop into the 20s overnight. Highs on Sunday will be slightly below normal levels ranging from the low to mid 40s under mostly sunny skies. Upper trough lifting from the central Plains and Midwest regions on Sunday will run into an amplified ridge resulting in flattening of the flow with the best dynamics passing to the N and W of the local area. However. a weak confluent flow over the Ohio Valley Mon morning translates across srn New England with the exit region of a 150+ kt H25 jet just to our south. Pcpn is expected to overspread the area from W to E after midnight...although with the system running into the upper ridge am not sure how robust amounts will be...especially at the coast. Have trended higher with the pops...but not ready to raise into the likely range just yet. NW zones have the highest chance for QPF...thus highest pops are there. Op EC is the wettest...NAM is driest and GFS is in between. Interestingly...there are only 2 GEFS members that support the wetter EC...but many of the ECEPS members have up to 1/10 inch QPF. If this trend continues pops will be raised. As far as p-type...appears that it should start as snow everywhere...and then gradually change over to rain from S to N as thicknesses increase through the low levels in addition to warming during the daylight hours. Low temps Sun night are tricky and may occur earlier than normal depending on the amount of cloud cover during the evening and evap cooling once pcpn begins. Pcpn tapers off W to E late mon morning/early aftn. Potential for generally up to an inch well NW of NYC with 1/2 inch or less at the coast before the changeover to rain. Monday morning commute will likely be impacted.
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&& .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
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Southern stream shortwave moves out of Mexico, and tracks across Texas Monday before weakening as it moves quickly across the southeast states Tuesday. Meanwhile, closed northern stream low moves across central Canada, making slow progress toward the Great Lakes mid week, then into New England late in the week. Differences noted in position and strength of this impressive trough is moves moves east late in the week. At the surface, two areas of low pressure will form along a frontal boundary. One over the Southeast that will push off the southeast coast Tuesday night, then head east. The other will develop over the Ohio Valley and pass north of the area into Wednesday. These systems associated with southern stream shortwave mentioned earlier. Cold air damming signature noted for Tuesday, so precipitation may start off as snow inland again, then change over to rain, with a mixture of rain and snow Tuesday night. Again, QPF is expected to be light. Temperatures will be within a few degrees of normal through mid week. Temps could jump slightly ahead of late week trough. Then leaned toward colder numbers Friday, closer to WPC and away from model blend.
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&& .AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
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Gusty WNW flow early this morning becomes NW during the day as high pressure slowly builds towards the local area. VFR through the TAF period with SCT-BKN cigs 4-6kft through this evening. Wind direction at city terminals will average to the right of 310 magnetic, except at EWR where it could be right at 310 magnetic. Gusts around 20 kt will persist at most terminals through daybreak, but may go more occasional at times. Gusts will increase after sunrise, with highest gusts 25-30 kt in the 15-20z time frame. Gusts will start to decrease around sunset. .OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY... .Late Saturday night-Sunday...VFR. .Sunday night...MVFR possible after midnight in chance of light snow. .Monday...Rain/snow mix possible early with MVFR possible in the morning. .Tuesday-Wednesday...MVFR possible in chance of wintry mix inland and chance of rain near coast.
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&& .MARINE...
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SCA continues on all waters today under a gusty NW flow. Have added ocnl gusts to 35 kt on the ocean waters as gale force gusts are a possibility through the day...however do not expect them to be frq enough for a gale warning. Winds begin to diminish this eve...with winds falling below sca on the non-ocean waters by 10pm. Winds and seas are expected to remain elevated through the night on the ocean. There is the possibility that gusts could linger for a few hours Sun morning the eastern ocean zone (Moriches Inlet to Montauk Point and out 20NM). Tranquil conds are then expected through Monday night. Expect conditions to deteriorate Tuesday into Wednesday as two areas of low pressure approach the waters, and winds increase ahead of these lows. Seas expected to build, but lowered forecast below Wave Watch III output.
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&& .HYDROLOGY... No significant precipitation (greater than a half inch) is forecast through Monday. Unsettled weather is possible mid to late week next week. However, no significant precipitation (greater than a half inch) is forecast at this time. && .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 10 PM EST this evening for ANZ330- 335-338-340-345. Small Craft Advisory until 7 AM EST Sunday for ANZ350-353-355.
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&& $$

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