textproduct: Gray - Portland

WHAT HAS CHANGED

Minor update to the Aviation section for the 12Z TAFs.

KEY MESSAGES

1. Dry weather continues through Sunday but with less wind and slightly warmer temperatures.

2. Unsettled weather makes a return toward the middle of next week after a dry start.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Dry weather continues this weekend with high pressure nudging in from the north. Temperatures will remain around normal with a cool night expected tonight. The coast can expect a cooling seabreeze this afternoon as well as Sunday afternoon as winds go locally onshore. RH values will bottom out in the 20s and 30s today and then trend slightly higher on Sunday. However, winds will generally be under 12 mph both days. Some clouds may invade southern zones later on Sunday as low pressure passes to our south.

KEY MESSAGE 2 DESCRIPTION...

Model guidance continues to suggest a dry start to the week as high pressure settles over New England, suppressing a coastal storm south of the region. There is growing confidence that this drier weather lasts through the day Tuesday as, since yesterday, ensemble means have trended toward a Rex Block lasting into midweek. Uncertainty in the timing is still high, but have seen a bit of a trend towards a slower onset to precipitation, during the day on Wednesday. It makes sense to see a cave away from the more progressive outcomes given the rather blocky and amplified upper-air configuration.

From Wednesday through Friday, POPs are generally 40-70% regionwide the entire three days, indicating a wet sequence. It is likely we will have some on-off periods of rainy weather rather than it rain the entire three days. By this range there are a lot of uncertainties on the surface low track and evolution. Some model solutions show a more progressive system riding along the trough axis overhead, while others show a low cutting off from the upper-level flow and stalling over the region. Finally, it is worth mentioning total precipitation Wednesday-Friday has the NBM mean near or above an inch across the entire forecast area, so while rainfall is expected to be spaced out over several days, we remain hopeful in some needed drought relief.

Speaking temperatures, it generally looks like a cooling trend through the week as clouds and precipitation are on the increase. Given the orientation of next week's surface features, we are likely to see onshore flow for the majority of the week. This suggests cool conditions along the immediate coast, with milder temperatures focused along and west of the I-93 corridor.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

VFR prevails today through Sunday night. Winds will be light today with a sea breeze impacting coastal terminals starting around 16Z. Winds will be light Sunday and will primarily be out of the east-southeast.

Outlook: Monday: Generally VFR conditions expected with no significant weather.

Tuesday-Friday: Generally VFR, but MVFR possible with shower activity. Coverage of any showers next week is highly uncertain at this time.

MARINE

Through Sunday...Winds and seas continue to remain below SCA levels with broad high pressure stretching from eastern Canada into the Northeastern US.

Relatively tranquil waters are expected through Tuesday. From Wednesday onward, winds and seas will rise and may flirt with low-end SCA thresholds.

GYX WATCHES/WARNINGS/ADVISORIES

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