textproduct: Gray - Portland

WHAT HAS CHANGED

No major changes were needed this evening as quiet weather continues.

KEY MESSAGES

1. Dry weather continues through Tuesday with temperatures around seasonal averages.

2. Wet weather makes a return for the second half of the week.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

High pressure will generally dominate the weather pattern through Tuesday with dry conditions and temperatures around normal for this time of year (maybe a touch above normal for a few locations).

Most areas should see decent radiational cooling tonight given clearing skies and light winds. Lows are forecast to mainly be in the mid to upper 30s but wouldn't be shocked to see some lower 30s by Monday morning. By Monday afternoon, we will warm into the 60s across most of the forecast area but a few upper 50s will be possible over the higher terrain and a few lower 70s will also be possible across southern New Hampshire.

Tuesday will be similar but a touch cooler, drier, and a little bit breezier as high pressure slides off to the east and the pressure gradient modestly tightens. There will be minimum relative humidity values in the 25 to 35 percent range across most of the forecast area Tuesday afternoon with the exception of coastal areas. Southeast winds in the 8 to 15 mph range are in the forecast with some gusts in the 20 to 25 mph range. Thus, we could see some elevated fire weather concerns Tuesday afternoon and it will be period to watch.

KEY MESSAGE 2 DESCRIPTION...

The mid-level ridge will begin to break down on Wednesday as a trof axis continues to slide eastward over the Great Lakes region. Partly to mostly cloudy skies will prevail with an isolated shower possible, especially during the afternoon. High temperatures into the 50s will be common along the coast and across eastern areas due to onshore flow with lower to middle 60s possible in NH. Scattered showers will remain possible Wednesday night with lows into the 40s.

A widespread soaking rainfall will then arrive Thursday into Thursday night as an area of low pressure tracks over the Gulf of ME. Latest NBM and ensemble based guidance is in generally good agreement that this system should bring between 1-2" of rainfall to the region, with locally higher amounts possible. Given the ongoing drought conditions and low river/stream flows, flooding is not anticipated to be a concern. This system is then progged to become vertically stacked and cutoff from the main steering flow through potentially the upcoming weekend. This will result in a prolonged stretch of mostly cloudy and cool conditions with showers at times.

AVIATION /00Z MONDAY THROUGH FRIDAY/

Through Monday...VFR prevails through Monday with light easterly winds, variable at times.

Outlook:

Monday Night: VFR conditions with light and variable winds.

Tuesday/Tuesday Night: VFR conditions expected. E-NE winds of 5-15 kts during the daytime before light and variable overnight.

Wednesday/Wednesday Night: Lowering ceilings with restrictions possible by 00Z Thursday. Scattered SHRA are also possible. E winds at 5-15 kts.

Thursday/Thursday Night: Restrictions likely due to low ceilings and RA. E-NE winds of 15-25 kts.

Friday: Restrictions continue but with some possible improvement.

MARINE

Sub-sca conditions are expected through Tuesday as high pressure builds over the waters.

Seas outside of the bays will remain elevated at 3-6 ft Wednesday through at least Friday, likely necessitating a prolonged SCA. In addition, a period of E-SE wind gusts up to around 30 kts is possible Thursday into Friday, especially across the near shore waters and Penobscot Bay.

GYX WATCHES/WARNINGS/ADVISORIES

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