textproduct: Gray - Portland

WHAT HAS CHANGED

No significant changes to the going forecast this Sunday morning.

KEY MESSAGES

1. Low pressure crossing southern New England brings periods of rain through early this afternoon followed by a chance of a few thunderstorms late afternoon and early evening, mainly across western NH.

2. High pressure will build across New England for the first half of this week, bringing mainly dry conditions and cool temperatures. A frontal boundary may bring increased shower chances late in the week.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Low pressure forming near southern New England this morning will move exit east of Cape Cod during the late afternoon and evening. Models continue to show a rapid increase of deep moisture tonight into Sunday morning as PWATs climb to 1.5 to 2 inches. CAMs and global models have now started to show broad forcing for ascent leading to an axis of rain extending north of the developing low across much of NH through this morning which has resulted in a slight increase of QPF. This axis of rain will then become focused across southern NH into the coastal plain of Maine late morning into the afternoon as areas to the NW see a break in precipitation. Rain then moves offshore by evening.

A cold front will slide east across Upstate NY this evening with showers and storms forming along the front. These showers and storms will approach the CT Valley around sunset while there is potential for lingering MUCAPE to keep chances for thunder in the forecast. Instability wanes overnight with mainly a broken line of showers crossing the area with the cold front. Total QPF will vary by location depending on where convective showers are most persistent. Some areas may only see a quarter inch from this, but others up to an inch. Rain chances diminish NW to SE as the cold front moves offshore Monday morning.

KEY MESSAGE 2 DESCRIPTION...

High pressure over New England will keep the area dry and seasonable. Temperatures look to be in the upper 70s on Tuesday and Wednesday. The second half of next week looks more unsettled, with a couple frontal passages possible between Wednesday and Friday, as a couple weak waves of low pressure moves across eastern Canada. High pressure looks to return for the weekend, with drier conditions likely then.

High pressure will remain over the forecast area through Tuesday night before shifting offshore by Wednesday. Dry conditions will persist with highs on Tuesday into the lower 70s before warming into the middle to upper 70s on Wednesday. Some increase in cloud cover will keep lows warmer with readings into the 40s and 50s.

Shower chances then increase Thursday into Thursday night as a frontal boundary and associated weak wave of low pressure drops south out of Canada. Drier conditions are then possible as we approach next weekend.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

Through Tonight...Mainly VFR through 06-09Z this morning with cigs quickly lowering to MVFR and localized IFR through 12Z. Periods of IFR and LIFR in low cigs and rain is then likely through much of the day. Some improvement is possible this afternoon across southern and western NH while restrictions likely linger into Sunday night elsewhere before a cold front crosses early Monday morning for improving conditions behind the front.

Outlook:

Monday/Monday Night: Any lingering restrictions early in the morning will quickly lift with VFR conditions expected. Daytime NW wind gusts up to 25 kts are possible. Valley FG is possible Monday night at LEB and HIE.

Tuesday/Tuesday Night: VFR conditions expected.

Wednesday/Wednesday Night: VFR conditions expected.

Thursday/Thursday Night: Restrictions possible in developing SHRA.

MARINE

Low pressure develops near southern New England this morning and exits east of Cape Cod Sunday afternoon bring periods of rain and fog. Winds and seas will remain below SCA thresholds as this system passes with south winds briefly turning easterly. A cold front then crosses Sunday night shifting winds offshore by Monday morning with winds and seas remaining below SCA thresholds.

Outlook:

High pressure will keep winds and seas below SCA criteria Monday through at least mid to late week.

GYX WATCHES/WARNINGS/ADVISORIES

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