textproduct: Gray - Portland

WHAT HAS CHANGED

No significant changes since the previous forecast cycle.

KEY MESSAGES

1. Low pressure will continue to bring a period of rain tonight.

2. High pressure over southern Canada slides east Monday through Wednesday providing fair weather and seasonably cool temperatures.

3. There is a signal for a slow moving coastal system near the East Coast late in the week. Impacts will be track dependent, which remains uncertain at this time range, while the potential exists for rain, gusty NE winds, and high surf sometime over next weekend.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Low pressure passing to our south along a nearly stationary frontal boundary will continue to bring a period of light rainfall through the first half of tonight. No flooding issues are expected with rainfall amounts generally ranging from a tenth of an inch or less from Augusta and points north and east with a quarter to a half inch elsewhere. Fog is likely overnight as light winds allow the low-level moisture to stick around and it may become locally dense. Low temperatures will range from the lower 40s across much of interior ME with middle to upper 40s elsewhere.

KEY MESSAGE 2 DESCRIPTION...

Confidence is high that fair weather will prevail Monday through at least Wednesday with fair weather likely continuing into Friday. Broad high pressure over southern Canada will be the source of this fair weather as it drifts east through the week. As the high remains centered north of the area, temperatures will trend cooler than normal for both day time highs and overnight lows. This will translate to highs in the low to mid 60s and lows in the 30s to 40s. There will likely be favorable radiational cooling conditions most nights and it is likely some spots south of the mountains will see some frost.

KEY MESSAGE 3 DESCRIPTION...

For the past several model cycles there has been a signal for a cut off upper low near the East Coast spawning at least one surface low in the vicinity of the Gulf Stream. While this signal has been somewhat consistent there has been large model to model and run to run variability in the strength and track of a potential coastal low near the East Coast late in the week through next weekend. The current envelope of solutions ranges from mostly a miss south and east of the area to a seasonably strong area of low pressure near the Gulf of Maine. The former will still likely bring some high surf to the area and possibly some measurable rain, while the latter will bring greater potential for coastal impacts as well as gusty winds and rain into the interior. At this time, this system is around 6 days out so it will likely take a couple more days to gain some confidence in the track and strength of this potential system.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Through 18Z Monday: -RA and BR/FG will continue to result in lowering restrictions through this evening with IFR-LIFR restrictions expected overnight through around 12Z Monday. Winds will be light and variable. VFR conditions are then expected later Monday with N wind gusts up to 20 kts possible. No LLWS is anticipated through the period.

Outlook:

Tuesday-Friday: Mainly VFR outside of nighttime valley fog.

MARINE

Low pressure passing south of the waters will continue to result in light onshore flow through tonight along with light rain. Flow will become offshore on Monday with N wind gusts up to around 20 kts possible outside of the bays. Seas will be at 1-3 ft.

High pressure will remain centered north of the waters through mid week while an area of low pressure develops offshore of the Mid Atlantic. Winds and seas likely remain below SCA thresholds into Tuesday. A strengthening NE gradient will bring potential for periods of SCA conditions Wednesday and Thursday and potential for Gales late in the week depending on the track of the low pressure system. Regardless of track, seas will likely build in excess of 5-7 around Thursday and continue to build into the weekend.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...None.