textproduct: Gray - Portland

WHAT HAS CHANGED

Overall no significant changes in the forecast with this update as guidance remains reasonably consistent in with the overall pattern evolution. Still not seeing any major weather makers over the next week.

KEY MESSAGES

1. A couple of relatively low-impact systems to affect the region today into Friday with some mountain snows and rain in most other areas.

2. Below normal temperatures over the weekend with mostly dry weather.

3. Pattern turns more active early to middle of next week.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

A warm front lifting through the region early this morning will aid in the the development of light snow in the mountains and a period of light rain or rain showers south of the foothills. There could be some slippery spots in the mountains and portions of the foothills early this morning, but overall snowfall amounts should be less than 2 inches. South of there, rainfall amounts will be very light. In fact some areas in the far southern zones may remain dry.

The warm front that will lift northward early this morning will move back southward as a cold front during the afternoon. Southwesterly flow south of the front will allow temperatures to warm into the 60s across southern zones and 50s elsewhere except the far north. Moisture streaming eastward along and in the wake of the sagging front will aid in a renewed batch of rainfall to begin across the region this afternoon. Some model guidance indicates that there may actually be a short period of heavy rainfall across southern zones with a few rumbles of thunder possible this evening.

As far as precipitation type goes this afternoon and evening, we are looking at all rain. However, as the precipitation shield moves out later this evening, it's possible that a very brief period of snow occurs on the northern fringe.

High pressure moves into the region for Friday with dry weather and colder temperatures.

KEY MESSAGE 2 DESCRIPTION...

Broad high pressure builds in over the weekend. The core of the cold airmass will pass overhead Saturday morning through the afternoon. Lows Saturday morning will bottom out in the single digits across the north and in the teens south of the mountains. Highs saturday afternoon will range from the 20s north to mid 30s south. Another night with lows in the single digits north to teens south is likely Saturday night with temperatures starting to rebound Sunday as flow turns more southwesterly.

KEY MESSAGE 3 DESCRIPTION...

Zonal flow across the CONUS early next week will become more amplified as a series of Pacific troughs march across the West towards the middle of next week. A short wave within zonal flow pattern will bring a clipper system across southeast Canada Monday that will bring chances for rain and snow showers in the mountains. Thereafter, a signal exists for above normal precipitation through the end of next week as multiple waves eject out of mean troughing centered over the Rockies.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Through 12Z Friday...Ceilings ranging from IFR to MVFR from PWM, PSM, AUG and RKD will gradually improve to VFR later this morning or early afternoon. Intermittent light rain may also occur but little to no visibility restrictions are expected. VFR elsewhere for much of today. Ceilings lower again late this afternoon and evening as the next round of rain moves in with widespread MVFR to IFR restrictions. Rain could be briefly heavy, especially over southern NH and SW Maine. Conditions should start to improve after 07Z-09Z tonight as northwest winds start to increase (possibly gusting 20-25 kt prior to 12Z Friday morning).

Outlook...

Friday through Saturday night: Mainly VFR, no sig wx.

Sunday: Mainly VFR with SW winds gusting 15-20 kts. Some MVFR cigs possible at KHIE.

Sunday night and Monday: Clouds thicken and lower towards Monday morning. Scattered rain and snow showers possible at KHIE with rain showers south of the mountains, mainly north of a line from KLEB to KRKD.

MARINE

Active weather pattern will bring periods of SCA conditions straight through the weekend. First period of SCA conditions will be today and tonight as south to southwest flow increases ahead of a cold front. Winds will turn northwest tonight as the cold front pushes south. This will keep waves above criteria straight into Friday.

A period of SCAs may be needed Friday night in offshore flow. Winds and seas stay below SCA thresholds Saturday into Sunday morning. SW flow strengthens Sunday with SCAs likely needed by Sunday afternoon, lasting into Monday.

GYX WATCHES/WARNINGS/ADVISORIES

ME...None. NH...None. MARINE...Small Craft Advisory until 2 PM EDT Friday for ANZ150>154.