textproduct: Gray - Portland

WHAT HAS CHANGED

710 PM Update...Little change to the going forecast. However, after the rain of the last few days will have to watch for fog development overnight.

Previously...

No major changes to the forecast, but I have issued headlines for cold water hazards given the warm and fair weather expected this weekend.

Guidance has increased high temperatures on Tuesday and Wednesday, with lower 90s potentially more widespread across southern NH than previously expected. This may allow for a slight increase in CAPE as well, increasing the chances of see thunderstorms across the interior Tuesday afternoon.

KEY MESSAGES

1. Rain comes to an end this evening and then the pattern turns warmer for the weekend. After a long below normal stretch of weather, outdoor recreation will be in high demand and area inland and ocean waters remain very cold.

2. Warmer than normal temperatures arrive beginning this weekend, and may be much above normal parts of next week. Warmer temperatures on Tuesday and Wednesday will allow for some scattered thunderstorms in the evenings of both days.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Rain and showers continue to gradually diminish in intensity and coverage. I expect that even cloud cover will largely scatter out overnight. That will lead to patchy radiation fog developing. For now confidence is the highest in the major river valleys, so that is where I have included it for now. Any fog will lift quickly with sunrise Sat morning. Also worth noting that the astronomical high tide tonight is forecast to be around 11.2 ft at Portland. Little to no surge is expected, but water levels will be elevated overnight.

Then attention will turn to warming temps. Widespread 70s are expected both Sat and Sun. This will be the first well above normal stretch in a while, and the expectation is that lots of people will be anxious to get out and enjoy that weather. The concern is that inland and ocean waters remain very cold. For the ocean waters I have issued a Beach Hazard Statement to highlight those waters temps in the 40s still. Inland, rivers and lakes are cold, plus recent rainfall has the rivers running swift. So I have gone ahead and issued a Special Weather Statement for inland cold waters. There is some threat for showers and thunderstorms late Sat, but generally expecting those to be weakening as they arrive in western portions of the forecast area.

KEY MESSAGE 2 DESCRIPTION...

Early next week, high pressure will start to build over New England, allowing for a gradual heating trend into Monday. A sea breeze is likely on Monday, as the high moves eastward allowing for southerly onshore flow to persist in the afternoon. The sea breeze should keep coastal areas and parts of central Maine in the lower 70s on Monday, with upper 70s and 80s mainly confined to areas west of I-93.

Monday night, winds calm and shift to southwesterlies. This will allow for warm air and moisture advection, with temperatures and dewpoints running at least 10F warmer on Tuesday. High temperatures in the lower 90s can not be ruled out over southern New Hampshire, with below 80F high temperatures staying confined to the Midcoast. The daytime heating and extra moisture looks to collide with a cold front moving southward Tuesday afternoon. Soundings are already showing an unstable environment across northern New England with 600- 1200J of CAPE and around 30-35kts of wind shear. Within this environment, storms may contain at least small hail and gusty winds.

Another hot day is forecast on Wednesday as well, with high temperatures maybe only a couple degrees cooler from Tuesday. Another cold front looks to move southeastward Wednesday afternoon, arriving into another unstable environment Wednesday evening, with at least 1000J of CAPE and 35kts of shear. So between Tuesday and Wednesday night, it seems likely that Wednesday night's storms could pose more of a severe threat than Tuesdays, but both days have the potential to see minor convective impacts across the interior. With both days, a small marine layer along the coast is likely to keep stronger storms confined to the interior. Temperatures start cooling off further for the end of next week.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

Rain is gradually coming to an end and coastal storm is pulling away so gradual improvement to VFR conditions is expected this evening. The question then becomes the degree of clearing and whether radiation fog develops. At the very least I anticipate that the major river valleys will see some fog, so I have included mention in the TAFs at LEB and HIE. Elsewhere the confidence was too low to include at this time. Widespread VFR conditions are expected Sat.

Outlook:

Saturday Night: VFR conditions expected.

Sunday: VFR conditions expected.

Sunday Night: VFR conditions expected.

Monday/Monday night: VFR conditions expected.

Tuesday/Tuesday night: MVFR due to thunderstorms.

Wednesday: MVFR due to thunderstorms.

MARINE

Still dealing with large seas between 5 and 7 feet generally across the coastal waters. These will slowly diminish thru the weekend. I have extended the SCA for the coastal waters thru Sat night. The main concern will be warming air temps and very cold ocean temps. Increasing recreation will make the cold water a hazard. Mostly light and variable winds are forecast over the waters next week with seas of 2-4ft expected.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Beach Hazards Statement from Saturday morning through Saturday evening for MEZ023>028. NH...Beach Hazards Statement from Saturday morning through Saturday evening for NHZ014. MARINE...Small Craft Advisory until 5 AM EDT Sunday for ANZ150-152-154.