textproduct: Gray - Portland

WHAT HAS CHANGED

No significant changes with this forecast update.

KEY MESSAGES

1. High pressure brings fair weather today and Tuesday with warming temperatures and comfortable humidity levels.

2. Humidity increases on Wednesday and will remain elevated through the end of the week with daily chances for showers and thunderstorms. Highs in the 80s to low 90s combined with the humidity will pose a heat risk.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

Highs pressure builds in from the northwest this morning and will settle south of New England Tuesday. This will bring fair weather with highs today in the upper 70s to low 80s increasing into the mid 80s on Tuesday. Northwest flow aloft will help keep dew points in the 40s today and in the 50s Tuesday.

KEY MESSAGE 2 DESCRIPTION...

Ridging aloft will build into the Northeast by Wednesday morning. An active troughing pattern over the Northern Plains will help keep the ridge axis near the East Coast through Friday while short waves/remnant convection attempt to move atop the ridge. Ensembles are in good agreement that temperatures aloft will run above well normal along with anomalous moisture over the Northeast. The latest NBM brings dew points into the mid 60s Wednesday with these high dew points persisting into Friday and possibly into Saturday. The warm air aloft will promote highs into the 80s to low 90s while daily chances for clouds, showers, and thunderstorms may limit high temperatures from reaching their full potential.

Models are in decent agreement that one wave will move into the ridge late Wednesday into Wednesday night bringing the best chances for showers and thunderstorms through the end of the work week. The convective parameter space does not look all that impressive so the risk for any strong storms appears low. The ridge rebuilds over the Northeast Thursday while there will chances for diurnal showers and thunderstorms. Troughing over the Northern Plains attempts to push east Friday with flow strengthening aloft over the eastern Great Lakes and a cold front making a push towards the Northeast. Most available guidance holds the front off until late Friday and some solutions don't have it reaching New England until Saturday if it is able to cross at all. Therefore Friday looks to remain very warm and humid. This front may be one to watch as it may provide a source for strong to severe thunderstorms as Machine Learning guidance out of CSU is picking up on that signal.

AVIATION /06Z MONDAY THROUGH FRIDAY/

Through 06Z Tuesday...Mainly VFR through 12Z this morning, except fog could bring IFR to LIFR conditions at LEB and HIE early this morning. VFR prevails the rest of today with an afternoon sea breeze possible along the coast. VFR prevails tonight while patchy fog cannot be ruled out at LEB and HIE.

Outlook... Tuesday: VFR conditions expected under mostly clear skies.

Wednesday-Friday: Generally VFR conditions expected, but afternoon showers and/or thunderstorms may bring about TEMPO MVFR conditions.

MARINE

A cold front has pushed through the waters with steady north flow in its wake. These winds will gust to around 20 kts through morning with the outer waters seeing gusts to 25 kts. High pressure builds in today and settles south of the waters through Wednesday. This will allow for winds and seas to remain below SCA thresholds through the period.

GYX WATCHES/WARNINGS/ADVISORIES

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