textproduct: Gray - Portland

SYNOPSIS

High pressure moves offshore this morning. The next disturbance crosses New England later today and this evening bringing periods of snow showers, mainly in the mountains but some should also be seen toward the coast as well. High pressure returns Monday into Tuesday while an area of low pressure develops over the Great Lakes. This low pressure system will slowly track into SE Canada lifting a warm front into New England Tuesday night followed by the attendant cold front crossing Thursday. Cooler and breezy conditions then follow to close out the week.

NEAR TERM /THROUGH TODAY/

High pressure ridging overhead this morning will move eastward and be located well offshore by noon. A negatively-tilted short wave trough will quickly approach from the west this afternoon with associated low pressure surface reflection.

Clouds will quickly overspread the area from west to east this morning with some light snow or snow showers moving across the CT River around noon. Enough moisture, forcing for ascent, and instability should be present to allow for this light precipitation to move eastward, especially across southern and central zones on the nose of the short wave trough during the afternoon and early early evening hours.

The precipitation may start as rain at lower elevations, but that should be relatively brief. Not everyone will see snow, but a quick coating is not out of the question where it does, even at the coast by the time it starts getting dark. Temperatures will drop well down into the 30s by late afternoon so slippery spots are possible.

SHORT TERM /TONIGHT THROUGH MONDAY/

Any precipitation associated with the short wave trough will move offshore this evening. Thereafter, mountain snow showers will be the main theme while coastal regions gradually clear out well after midnight.

A fair weather day is expected on Monday with highs in the 40s at lower elevations and 30s in mountain valleys. NW winds may gust up to around 20 MPH.

LONG TERM /MONDAY NIGHT THROUGH SATURDAY/

Overview: Dry weather is expected Monday night into Tuesday afternoon as surface high pressure moves across the region before exiting to our east by Tuesday evening. Precipitation chances will then increase Tuesday evening into early Wednesday as a broad trof arrives from the west. A cold front will then cross on Wednesday night into Thursday with colder temperatures and upslope snow expected behind this front.

Impacts: Depending on temperature profiles, a wintry mix of precipitation is possible Tuesday night into early Wednesday morning across portions of the foothills and points north.

Forecast Details: Surface high pressure will begin to exit to our east on Monday night with increasing clouds from west to east as they ride along the H5 ridge axis. It will otherwise be a cold but dry night with overnight low temperatures into the 20s.

Tuesday looks to feature mostly cloudy skies as high pressure moves across the Gulf of ME ahead of a trof axis that will be approaching from the west. Much of the daytime should remain dry though with highs mostly into the 40s. Precipitation will then overspread the region on Tuesday evening and night before ending by around daybreak on Wednesday in most locations. It is possible that this could begin as some snow across portions of the foothills and points north before transitioning to rain overnight on Tuesday night. During this transition, a brief wintry mix is possible which could result in locally slippery travel. Low temperatures will range from the 30s across the interior with 40s along the coast and in southern NH.

Rain should end early Wednesday but skies will remain mainly cloudy with high temperatures into the 40s and 50s. A cold front then will likely cross Wednesday night, bringing scattered rain and snow showers with low temperatures primarily into the 30s. Temperatures are then likely to cool to near or a little below avg through the remainder of the week and upcoming weekend with upslope snow across the mountains and towards the Canadian Border.

AVIATION /02Z SUNDAY THROUGH THURSDAY/

Short Term...A period of light snow or snow showers are expected this afternoon and early evening which may bring conditions down to MVFR at times, especially across western NH. A return to VFR is expected tonight downwind of the mountains, with VFR conditions continuing through Monday.

Long Term...VFR conditions expected Monday night through 00Z Wednesday. Restrictions are then likely Tuesday night into Wednesday morning as -RA arrives along with lower ceilings. Conditions should improve later Wednesday with mainly VFR conditions through Thursday. Winds will largely remain out of the west at or below 20 kts.

MARINE

Short Term...Conditions are expected to remain below SCA levels today through Monday.

Long Term...SW wind gusts could approach 20 kts Tuesday afternoon but otherwise winds and seas are expected to remain below SCA levels through Wednesday before increasing out of the W late Wednesday night into Thursday behind a cold front.

GYX WATCHES/WARNINGS/ADVISORIES

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