textproduct: New York

SYNOPSIS

High pressure moves off the northeast and mid Atlantic coast today as a frontal system approaches from the west. A strong cold front approaches tonight as deep surface low pressure moves through the eastern Great Lakes and into southern Canada. The cold front moves through the area Friday morning. High pressure then briefly builds in for the start of the weekend. A warm front passes on Saturday followed by a cold front late Saturday night into Sunday. A secondary cold front passes Sunday night. High pressure returns Monday. Another frontal system looks to impact the region Tuesday into Wednesday.

NEAR TERM /UNTIL 6 PM THIS EVENING/

Quiet before the storm as surface high pressure over the eastern sea board moves off the northeast and mid Atlantic coast through today. Meanwhile deep low pressure over the upper midwest tracks into the Great Lakes region. Return flow around the high begins this afternoon as light winds become southeast, and then southerly, as a result warm advection will be weak this morning, and increase this afternoon. Clouds will be increase late in the day. Temperatures will be 5 to 8 degrees above seasonal normals.

SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/

Key Messages:

* A strong cold front will move through the area on Friday bringing strong to locally damaging winds and moderate to heavy rain, along with isolated thunderstorms.

* Potential tying or record breaking temperatures early Friday fall back into the 20s Friday night, to below normal levels. Any leftover moisture may freeze if drying does not occur.

A strong cold front moves through the region Friday accompanied by a narrow line of convection, with a slight chance of thunderstorms. The cold front is associated with an upper level deep trough that moves through the Great Lakes region, and into the the northeast, becoming negative, by late Friday. The associated deep surface low tracks through the upper midwest, through the Great Lakes region, and then into southern Canada. An impressive LLJ develops off the mid Atlantic coast late tonight into Friday with 900 mb winds of 60 to 80 kt. With a low level inversion much of this wind will not be mixing to the surface. However, with the chance for moderate to heavy showers and potentially embedded thunderstorms, the higher winds may be brought to the surface. With this potential a Wind Advisory remains in effect for the entire region from late tonight through Friday evening.

The cold front moves through on Friday and then winds become W/NW. Gusts pick up again at this time with decent cold advection and wind gusts potentially could be as strong or strong than with the showers ahead of the cold front.

With early highs Friday morning there is the chance of tying or breaking high temperature records at a few of the climate locations. See Climate section for details. Temperatures then fall late morning through Friday night. There is some concern of leftover moisture freezing before drying can occur.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Key Messages:

* Mainly dry conditions are expected through the weekend and Monday. Precipitation returns to the forecast Tuesday and Wednesday next week.

* Temperatures moderate this weekend, but frigid temps return on Monday. Temperatures moderate again towards mid part of next week.

High pressure builds briefly from the south early on Saturday. Low pressure over Ontario brings a warm front through late Saturday followed by a cold front late Saturday night into early Sunday morning as the low moves into Quebec.

Atmospheric moisture looks quite low, so no precip expected with the warm frontal passage. However, forcing may be strong enough with the cold front along with a slight increase in moisture to lead to a few brief very light rain/snow showers or sprinkles/flurries early on Sunday. At this point, low levels appear to remain dry enough so no measurable precip is expected for the weekend.

We'll dry out following the cold front under westerly winds, with a secondary cold front bringing in even drier northwesterly flow Sunday night.

Prior to the secondary front, temperatures should remain moderated with highs on Saturday and Sunday in the upper 30s to mid 40s. Lows on Saturday night will be in the 30s with most above freezing. However, due to the secondary cold front bringing in cooler continental air under northwesterly flow, lows on Sunday night look to return to the low to mid 20s.

Saturday through Sunday night will also be under a stronger pressure gradient with high pressure south and low pressure north, so expect a period of stronger winds through the weekend.

High pressure builds into the area from the Great Lakes on Monday with cold air settled. Highs on Monday will be in the low to mid 30s and lows return to the 20s Monday night as high pressure centers itself over the region.

High pressure backs to the south as Tuesday as another frontal system from Canada looks to impact the region Tuesday into Wednesday. Details on this system are still a little murky with some variability among the available model guidance, but POPs do return towards and during the middle of next week with this system.

OUTLOOK FOR 06Z FRIDAY THROUGH MONDAY

Late Tonight: MVFR to IFR with rain. S wind gusts increasing to 25- 40 kt. SSW LLWS 50-60kt at 1500-2000kft.

Friday: Rain in the morning with MVFR/IFR, then rain ending with VFR. S to SW winds G35-45 kt in the morning, shifting W G25-35 kt in the afternoon. LLWS early.

Saturday: VFR.

Sunday: Mainly VFR. Chance of MVFR with light rain/snow early in the morning. W winds G20-25 kt.

Monday: VFR. NW winds G20-25 kt.

Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90

MARINE

The Gale Warning remains in effect across the forecast waters tonight through Friday evening. Otherwise sub SCA conditions are expected through today with strengthening winds and gusts tonight ahead of a cold front. With the Gale Warning there is the potential for 40 to 45 kt wind gusts during late tonight into Friday morning and then again Friday evening and night. During the morning period, isolated gusts up to 50 kt are possible.

A SCA will likely be needed on the non ocean waters Sat night as well as strong westerly winds continue behind a cold front. SCA conditions likely remain on the ocean waters into Mon. A period of gale gusts are possible on the ocean Sat night.

HYDROLOGY

Brief heavy rain will be possible late tonight into early Friday with showers moving across as well as any embedded thunderstorms. These will be quick moving and as such, are not expected to result in significant accumulations of rainfall. Around 3/4 to 1 1/4 inches of rainfall, with locally higher amounts, are possible. While hourly rainfall rates will mainly be around 0.25in/hr or lower, heavier showers and thunderstorms may produce rates closer to 0.50-0.75in/hr.

Outside of minor flooding in low lying and poor drainage areas in localized areas where multiple rounds of heavy downpours are received, no other hydrologic impacts are expected.

No hydrologic impacts are expected Saturday through Wednesday.

TIDES/COASTAL FLOODING

One high tide cycle of concern, early Friday with mostly minor coastal flooding forecast.

Hazards are as follows:

Coastal Flood Advisories:

1.) Southern Nassau NY, Southern Queens NY, from 4AM to 10AM EST Friday.

2.) Hudson NJ, Eastern Essex NJ, Eastern Union NJ, Staten Island NY, Brooklyn NY, from 5AM to 11AM EST Friday.

3.) Southern Suffolk NY, from 6AM to 1PM EST Friday.

Coastal Flood Statements:

1.) Manhattan NY, from 5AM to 10AM EST Friday.

2.) Southern Fairfield CT, Southern Westchester NY, Bronx NY, Northern Queens NY, Northern Nassau NY, Northwest Suffolk NY, from 8AM to 1PM EST Friday.

Astronomical levels are running high as we approach a new moon. There is extra surge expected as a strong cold front approaches from the west with strong southerly flow ahead of it and higher ocean seas. The timing of the high tides (early to mid Friday morning) is such that the ocean shorelines, South Shore Bays, and NY Harbor will have their respective high tides closer to the timing of the max winds.

Took a blend of ETSS, ESTOFS, Stevens 50th and 95th percentiles, and PETSS 50th percentile surge guidance with some individual manual adjustments thereafter.

Basically have more of the manual adjustments up with total water level along the south shores of Long Island, where combined increased wave action and onshore flow will make for higher total water levels.

For the NY Harbor and South Shore Bays as well as the rest of the southern shorelines of Long Island, widespread minor coastal flooding is expected. Within the South Shore Bays, there is forecast some isolated moderate coastal flooding such as at Freeport. Coastal flood advisories are in effect for early Friday for these locations.

For Western Long Island Sound shorelines, minor coastal flooding is forecast but will not be as widespread. This is because of the later time of high tides (generally late Friday morning) coinciding with when winds will be relatively lower and past the max wind timing. Less onshore flow is expected for these locations. Total water level forecasts are less with forecasts that just reach the benchmarks of minor coastal flooding and not much beyond that. Coastal flood statements are in effect for early Friday for these locations.

CLIMATE

Record High Temperatures:

December 19: KEWR: 60/1931 KBDR: 57/1967 KNYC: 58/1931 KLGA: 57/1957 KJFK: 56/1967 KISP: 55/2017

OKX WATCHES/WARNINGS/ADVISORIES

CT...Wind Advisory from midnight tonight to midnight EST Friday night for CTZ005>012. NY...Wind Advisory from midnight tonight to midnight EST Friday night for NYZ067>075-078>081-176>179. Coastal Flood Advisory from 5 AM to 11 AM EST Friday for NYZ074-075. Coastal Flood Advisory from 6 AM to 1 PM EST Friday for NYZ080- 081. Coastal Flood Advisory from 4 AM to 10 AM EST Friday for NYZ178-179. NJ...Wind Advisory from midnight tonight to midnight EST Friday night for NJZ002-004-006-103>108. Coastal Flood Advisory from 5 AM to 11 AM EST Friday for NJZ006-106-108. MARINE...Gale Warning from 6 PM this evening to midnight EST Friday night for ANZ331-332-335-338-340-345-350-353-355.