textproduct: Gray - Portland

WHAT HAS CHANGED

Dry slotting continues to move into the area and the widespread precipitation has all but finished. Pockets of light snow and/or drizzle/rain will remain possible over the next couple of hours. Will give it a few more hours, but the Winter Weather Advisory will likely be able to be cancelled early around 18z or so unless something changes.

KEY MESSAGES

1) Pockets of light rain, snow, and drizzle will continue to impact the forecast area through the morning, but most of the precipitation has moved out.

2) 30 to 40 MPH wind gusts possible later tonight into Monday morning.

3)Above normal temperatures return Tuesday and Wednesday while a couple of weak clippers move through. Precipitation chances potentially linger into the end of the week.

DISCUSSION

Key Message 1 Discussion...

Dry slot has moved into the area making the dominant precip type drizzle outside of the western Maine mtns. Temps are largely hovering right around freezing. While I think freezing drizzle would be more likely to bring icy travel conditions if it were below freezing, there is a chance that 32 is cold enough for some slick spots. For the zones where freezing or sub-freezing temps are more widespread I have left the winter weather advisory in effect. Otherwise I have dropped zones where temps are mostly 32 to 35 degrees. However across western Maine I did leave a few zones in the advisory where it is warmer with the anticipation that colder air sloshes back towards the coast as the occlusion approaches and weak low pressure forms near the triple point.

Rapid drying takes place this afternoon. However, with a strong short wave trough moving across the region this evening and tonight snow showers or maybe a squall or two will be possible and this could make for slippery travel as residual water beings to freeze. Otherwise, plenty of upslope snow showers are expected across northern NH and portions of the western ME mountains tonight into Monday.

Winds pick up and become quite gusty, particularly across central and southern NH and southernmost ME where a period of gusts of 30 to 40 MPH will be possible tonight.

Key Message 2 Discussion...

Winds pick up and become quite gusty, particularly across central and southern NH and southernmost ME where a period of gusts of 30 to 40 MPH will be possible tonight. A wind advisory probably won't be needed due to time of day (lack of SFC heating) but we won't rule it out year and some guidance has gusts around 40 kt.

Key Message 3 Discussion...

A low amplitude ridge builds over the region Tuesday allowing for mostly clear skies south of the mountains and for temperatures there to climb into the upper 30s and low 40s. The mountains likely hold on to clouds and as a result temperatures top out in the low to mid-30s. Clouds increase Tuesday night as low pressure approaches from the Great Lakes Region. Ensembles continue to suggest the initial front associated with this system is moisture starved, with QPF less than a tenth of an inch. A light snow shower is possible in the mountains with some liquid sprinkles possible from the foothills southward.

Southwesterly flow continues Wednesday as a trough begins to dig into the central U.S. allowing this to be the warmest day of the week despite mostly cloudy skies. High temperatures climb into the low to mid-40s south of the mountains, and into the mid- to upper 30s to the north. As the low pressure passes to the north it drags another frontal boundary through and ensembles support a little bit more moisture with this one. After a warm day most locations likely see light rain to start, but this transitions to light snow from north to south as the night goes on. Ensemble mean QPF is currently suggesting QPF closer to 0.20", so better accumulation would be anticipated, but would still be light. The trough axis slowly moves closer to the region possibly providing enough forcing to allow light snow to continue into the day Thursday.

Global deterministic models have been flip flopping on the potential for an impactful system late in the work week, but support in their respective ensembles has consistently been lacking in the last handful of runs. It is going to depend on how this aforementioned trough digging in evolves as it pushes near the East Coast, but if I'm being honest the support is better for something late in the weekend time frame. There is plenty to watch as the pattern stays active, and we will continue to keep an eye on trends.

AVIATION /14Z SUNDAY THROUGH THURSDAY/

VFR quickly drop to IFR as precip spreads from south to north through tonight. Mainly rain is expected at MHT and PSM, CON and PWM with periods of rain, snow, and pellets are likely at, LEB, and RKD. Snow and pellets are likely at HIE and AUG, with freezing rain also possible at AUG and HIE. Precip ends as snow Sunday morning at most terminals, with IFR continuing through midday. Light snow continues at HIE and AUG into the afternoon. Improvement to MVFR is likely by late tomorrow afternoon, with VFR returning tomorrow night. HIE and LEB likely hold on to MVFR ceilings through Monday with upslope snow showers likely.

Outlook:

Monday night: VFR prevails at most terminals. MVFR possible at HIE.

Tuesday: VFR prevails at most terminals. MVFR possible at HIE.

Tuesday night: IFR possible in snow showers at LEB and HIE.

Wednesday: LEB and HIE gradually improve to MVFR as snow tapers off. MVFR prevails at all other terminals.

Wednesday night: IFR possible in snow showers at LEB and HIE. MVFR restrictions more likely at other terminals in light rain early but could lower to IFR overnight as rain transitions to snow.

Thursday: IFR possibly lifts to MVFR at LEB and HIE. MVFR elsewhere as light precipitation lingers.

MARINE

Low pressure deepens across the Gulf of Maine today, bringing SCA conditions in northeasterly flow today. Winds shift to westerly late today, and strengthen to gales across the outer waters as the low deepens across the Canadian Maritimes tonight into Monday.

An active weather pattern may keep seas 5ft+ through next week with frequent periods of wind gusts greater then 25kts as well.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Winter Weather Advisory until 7 PM EST this evening for MEZ007>009-012>014-020>022-033. NH...None. MARINE...Gale Warning from 10 PM this evening to 1 PM EST Monday for ANZ150-152-154. Small Craft Advisory until 1 PM EST Monday for ANZ151-153.