textproduct: Gray - Portland

WHAT HAS CHANGED

Loaded in the latest surface observations but otherwise no major changes were needed to the forecast at this time.

A Special Weather Statement has been issued to highlight the danger associated with the cold water temperatures across local bodies of water.

KEY MESSAGES

1. After steady light rain exits this morning, showers will linger through the day with warmer temperatures. A few thunderstorms are possible in the afternoon.

2. Temperatures run a couple degrees below normal this work week, featuring a period of mostly dry weather Mon and Tue followed by chance of areawide rain mid to late week. Overnight frost will be possible across interior locations Tuesday night if clouds do not increase markedly ahead of the next system.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Steady light rain will continue to move out of the forecast area early this morning, but showers will linger through the day as a cold front approaches in persistent southwest aloft. It will be much warmer today and moisture will also be on the increase ahead of the front. We could see a few dewpoints in the lower 50s across southern New Hampshire, coastal areas, and into the southern Kennebec Valley. Highs today will range from the mid 50s to the lower 60s across the north and in the sheltered valley. Mid to upper 60s are then likely most elsewhere except for southeast New Hampshire, where we could see some lower 70s.

Given the warmer temperatures and better moisture, we could see a bit of instability across the region by the afternoon hours. RAP soundings suggest the potential for 200 to 500 J/kg of MLCAPE and strong deep layer shear. Thus, the environment will be favorable for widespread convective showers and a few thunderstorms along and ahead of the cold front. Given the meager instability, severe weather is not expected but a few storms could end up being on the stronger side with gusty winds, small hail, and lightning being the main threats.

Showers and storms will diminish in the evening with the loss of heating. Lows tonight will be chilly behind the front, ranging from the low to mid 30s north, to the upper 30s and lower 40s south.

KEY MESSAGE 2 DESCRIPTION...

Little change to the going forecast at this time for the work week. Monday continues to trend dry with highs near normal. Tuesday looks dry as well with slightly lower temperatures. Depending on cloud cover Tuesday night, a frost will be possible for most areas away from the coast. A frost advisory may be needed.

On Wednesday and upper low and slow-moing attendant SFC low pressure approaches from the west. Various members of guidance are showing various amplifications of the short wave trough and speed of the system as a whole. The mean solution has conditions deteriorating conditions Wednesday afternoon in light rain which continues through Thursday. However, there is fairly large disagreement on the timing on the exit of this system where Friday could end up either wet or mostly dry. This includes the weekend too. Will continue to monitor trends but take a middle of the road approach with PoPs Fri into the weekend. Temperatures Wednesday onward should average below normal.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

Through 12Z Monday...While steady rain has ended, IFR/LIFR restrictions remain in place this morning due to low stratus/fog and some shower activity. Restrictions will be slow to improve with more showers through the day. Most locations should return to VFR/MVFR by around 18Z though. Winds will be out of the SW at 10-20 kts. A few thunderstorms are possible this afternoon but confidence is too low at the moment to include mention at any specific TAF site. For now, will utilize PROB30 groups for showery activity in the afternoon. Mainly VFR conditions are then expected tonight, although some low stratus may keep CIGs low near KRKD.

Outlook:

Monday and Monday night: VFR with daytime NW winds gusting 10 to 15 kts. Can't rule out a VCSH mid afternoon. Winds become light overnight.

Tuesday and Tuesday night: VFR. Winds NW gusting around 20 kt.

Wednesday and Thursday: Cigs lower through the day Wed as SHRA approach from the west. MVFR to IFR cigs Wed evening through Thursday, though there is low confidence in onset and duration.

MARINE

SCA conditions are likely to continue through tonight with southerly winds and 4-6ft seas.

Conditions look to remain below SCA Mon afternoon through Wed with a low chance of low-end SCA conditions Wed evening into Thu.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ150- 152-154.