Marine Weather and Tide Forecast for Kingston, NY

NEAR TERM /THROUGH TONIGHT/
Key Message:

- Widespread precipitation will occur this afternoon into Tuesday morning with a wintry mix including light ice accumulations for some locations north of I-90 the southern Adirondacks, southern VT and the northern Berkshires where Winter WX Advisories were issued 1 pm today to 10 am Tue.

Discussion:

As of 415 am EST...A brief respite in the active weather pattern will end today, as a diffuse frontal boundary associated with low pressure over the Upper Midwest and the western Great Lakes Region will lift northward across the the forecast area today. Clouds will thicken and lower this morning. The latest CAMs and HRRRS indicate the isentropic lift will increase in the afternoon for pcpn to break out. A northern stream short-wave will approach from the Ohio Valley. High pressure over s-cntrl Quebec will drift to the east northeast.

The timing for the onset of the pcpn was favored with a blend of the 3-km HRRR/NAMnest. Thermal profiles from the NBM were used initially with a trend close to the NAM, as some low-level cold air may be trapped initially over the northern zones. The good news is that the onset of the pcpn will be as temps rise into the 30s to lower 40s. A plain rain ptype is favored from roughly the I-90 corridor southward. Some pockets of freezing rain may occur over eastern Catskills and even the western Mohawk Valley.
An SPS may be used to account for a brief period of freezing rain.

The colder air is more entrenched over the southern Dacks and southern Greens for a period of snow mixed with some sleet due to wet bulb and dynamical cooling. A Winter Wx Advisory for the southern Dacks, southern VT and the northern Berkshires for 1-3" of snow and sleet into tonight, but also for a period of freezing rain. The HRRR FRAM looked too aggressive on the coverage of freezing rain accums, but the 3-km NAM, WPC Winter guidance looked more on track for snow and sleet to transition to some freezing rain over the elevated surfaces of the southern Adirondack Park and southern Greens, but some shallow low-level cold air with the southeast flow may be trapped in the CT River Valley, as we placed eastern Windham County in an Advisory. The northern Berkshires could have several hours of light icing based on losing ice in the clouds and the synoptic forcing weakening especially between 00Z-06Z. The model soundings also support the ice. Periods of light freezing rain or freezing drizzle may continue most of the night especially along the east/southeast slopes of the Adirondacks/southern Greens and Berkshires due to the upslope. We will have to monitor if southeast Warren Co. and portions of northern Saratoga have an extended period of icing and possibly an expansion of the WSW might be necessitated. Excellent collab with WFO BTV, BOX, and GYX for the issuance of the Advisory this morning.

Total QPF looks to be in the third of an inch to three quarters of an inch range. Flat ice amounts of a coating to around a tenth of an inch may occur in the advisory. Max temps today will be in the upper 20s to mid 30s over the mtns, and mid 30s to lower 40s in the valleys. The pcpn lets up tonight, but some cold air draining in from the north and east will allow for lows in the upper 20s to lower 30s over the southern Dacks, Lake George Saratoga Region, northern Berkshires, and southern VT.
Expect mid and upper 30s further south with some patchy fog and light rain.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
Key Messages:

- High confidence for a heavy precipitation event Tue night into Wed Night with at least 1.5 to 2.5 inches of pcpn.
Precipitation begins as all rain, likely changing to high- elevation snow before ending.

- Sharply dropping temps Wed night have a chance to produce flash freeze conditions in some areas

Discussion:

The Winter Wx Advisory for the southern Dacks, southern VT and northern Berkshires is until 15Z/10 am for the Tue morning commute but could be canceled sooner, if the threat for freezing rain diminishes. Eastern NY and western New England will be in warm sector on Tue with a secondary warm front moving through during the day. Light pcpn will occur due to weak lift.
Until the warm front moves through temps will hold in the mid 30s to lower 40s over most of southern VT and the Adirondack Park. Elsewhere highs should reach the mid 40s and lower 50s.

A full-latitude mid and upper level trough will be carved out over the central CONUS into the MS River Valley Tue pm. A strong mid and upper level jet will set up along the Appalachians into the Northeast. A low pressure system organizes over the TN Valley and moves toward the Ohio Valley by Tue evening. Upper level diffluence overspreads the region. The upper level dynamics become favorable, as the cyclone deepens near the right entrance region of a jet streak. Integrated Water Vapor transport increases over the Northeast, as moisture streams northeast from the Gulf and subtropics. In fact, PWAT anomalies are +1 to +3 STDEVs above normal on the latest NAEFS. The actual PWATs exceed an inch. The thermal profiles favor rain and expect periods of moderate to locally heavy rain to develop Tue night and extend through WED. It will be mild with lows in the mid 30s to lower/mid 40s.

The lead sfc cyclone may pass over w-cntrl NY based on the medium range guidance and ensembles, but another cyclone and the slow moving cold front will keep the rain going with strong QG lift aided by the mid and upper trough turning negatively tilted. The sfc cyclone may deepens to 990-995 hPa, as it moves near the NY and New England border by early Wed evening (00Z/Thu). High temps ahead of the front will range from 40s over the Adirondack Park to 50s across portions of southern VT, the Capital Region, Berkshires, mid Hudson Valley, Taconics and NW CT.

A strong thermal gradient with the front moves across the region. Expect strong cold advection and a rapid transition to snowfall west of the Hudson River Valley initially and then eastward toward the I-87 corridor and western New England. Light to moderate snow amounts are possible in the southern Dacks. We may need at least an advisory for 2-6" of snow. Elsewhere 1-3" of snow may occur over the eastern Catskills into the Mohawk Valley, as well as the southern Greens. The valley areas may get a coating to less than an inch. The rapidly falling temps may cause a flash freeze in some locations with lows in the upper teens to upper 20s. Please see the hydro discussion below, as 1.5-2.5 inches of precipitation may occur with locally higher amounts. Probabilities in the latest NBM for 48-hr QPF exceeding 2" 12Z TUE to 12Z THU are in the 55 to 90% range from the Capital Region, eastern Catskills and southern VT south and east now.

LONG TERM /THURSDAY THROUGH SUNDAY/
Key Messages:

- Lake effect snow shower chances (50%) Thursday into this weekend.

- Gradual temperature warm up beginning Saturday after a cold day Friday.

Discussion:

As an upper level trough moves to our north, chances of precipitation diminish from the southeast (Mid-Hudson valley region)
to the northwest (southern Vermont region) Thursday across eastern New York and western New England. For the western Adirondacks, lake effect snow showers have potential to continue off of Lake Ontario from Thursday evening through this weekend. Surface high pressure builds in for Friday and Saturday for a break in the precipitation chances, with the exception of the western Adirondacks. For Sunday, ensemble forecast models are in agreement for an upper level shortwave to move through that has potential to bring unsettled weather conditions to eastern New York and western New England.
Strength of this upper level shortwave and exact placement are still uncertain, so chances of precipitation are between 15 and 30 percent for most locations on Sunday into early next week.

Now onto temperatures, Thursday and Friday this week are still on track to be cold with highs in the low 20s in higher terrain and low 30s in the valleys. Friday and Saturday morning when most locations could see clear skies, temperatures could reach into the single digits where there is snow on the ground (such as the southern Green Mountains, southern Adirondacks, and Catskills) and elsewhere in the low teens. Beginning Saturday afternoon, we'll see a gradual afternoon high temperature trend of warming up. Highs on Sunday could reach into the low 40s in valley locations.

AVIATION /08Z MONDAY THROUGH FRIDAY/
VFR conditions continue for KALB, KPOU, and KGFL through 09/17z-19z when our next weather system arrives bringing rain for KPOU and KALB TAF sites and conditions transitioning to MVFR/IFR through the end of the TAF period. There is still uncertainty for KGFL in the precipitation type as temperatures could hover around freezing, but confidence is moderate (50%) for snow to start as the main precipitation type. For KPSF, low VFR and periods of MVFR could continue through tomorrow morning before the weather system arrives bringing MVFR/IFR conditions after 09/15z. Winds continue to be westerly at KALB and KPSF then transition to the southeast between 15z and 18z with light and variable conditions at KPOU and KGFL.

Outlook...

Tuesday Night: High Operational Impact. Definite RA.
Wednesday: High Operational Impact. Breezy. Definite RA.
Wednesday Night: High Operational Impact. Breezy
Definite SHSN
RA...SN.
Thursday: Low Operational Impact. Breezy. Slight Chance of SHSN.
Thursday Night to Friday: No Operational Impact. NO SIG WX.

HYDROLOGY
Multiple low pressure systems and a slow moving cold front will bring an extended period of rainfall Tuesday night into Wednesday evening before the precipitation transitions back to snow. Rainfall amounts may range from 1.5 to 2.5 inches across the Hydro Service Area (HSA). The rain may become heavy at times on Wed. Most of the HSA is in D1 (Moderate Drought) to D2 (Severe Drought) currently based on the latest US Drought Monitor.

Some ponding of water on roads, poor drainage and urban flooding will be possible in some locations due to the runoff and some snow melt. WPC Day 3 Excessive Rainfall Outlook has eastern NY in a Marginal Risk and western New England in a Slight Risk Wed-Wed Night for the potential of exceeding the FFG.
Current NERFC forecast hydrographs do not forecast any main stem river flooding. Colder air quickly moves back in Wed night turning any remaining rain to snow slowing down run off. We will continue to monitor any potential flooding, as widespread flooding is not expected at this time.

ALY WATCHES/WARNINGS/ADVISORIES
CT...None.
NY...Winter Weather Advisory from 1 PM this afternoon to 10 AM EST Tuesday for NYZ032-033-042-082.
MA...Winter Weather Advisory from 1 PM this afternoon to 10 AM EST Tuesday for MAZ001.
VT...Winter Weather Advisory from 1 PM this afternoon to 10 AM EST Tuesday for VTZ013>015.