Marine Weather and Tide Forecast for Kennebunk, ME

NEAR TERM /UNTIL 6 PM THIS EVENING/
Morning update...
Morning forecast on track with low humidity and warming temperatures, making for the best weather conditions on a Saturday in months. Temperatures will be seasonable with highs around 75-85, with dewpoints around 50-55. A slight breeze will be possible with daytime heating and mixing. A seabreeze is expected to develop under light flow, allowing for some cooling along the coast. Overall the forecast is on track.

Previously...
Nighttime microphysics satellite imagery early this Saturday morning shows mainly clear skies with just some hints of valley fog beginning to develop. The clear skies and low dew points have allowed for radiational cooling with readings down into the lower 40s across some northern valleys with 50s in most other locations. A few additional degrees of cooling is possible through sunrise.

An unusually nice Saturday is on tap for today as surface high pressure and H5 ridging moves overhead. Skies will be mainly sunny with light winds, becoming southerly late day with a developing sea breeze. High temperatures will be into the 70s and 80s with comfortably low dew points into the 40s and 50s.

SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/
Attention tonight turns towards an MCS that is currently moving across northern Minnesota. This convective system is progged to ride along the H5 ridge axis through the day today before arriving somewhere in New England by early Sunday morning. These systems are often tough to predict their movement with latest CAM guidance significantly further south than global guidance.
Despite these differences, there is generally good agreement that much of the region will receive rainfall and therefore increased PoPs across the board. Despite the late night nature of this system, there will be upper level energy for it to feed off of with low-level WAA in place. Therefore, while it should be undergoing a general weakening trend, a few thunderstorms are likely and some of which could be strong to severe with damaging winds the primary hazard. The latest D1/D2 SPC outlook places the entire region within a MRGL risk (level 1/5).

Low temperatures will be into the 50s and 60s.

This region of convection will exit later Sunday morning with clearing skies and warming temperatures into the 80s and 90s from north to south. Heat indices are expected to approach 100 degrees for a few hours during the afternoon and therefore issued a Heat Advisory in those locations. Will have to watch for any lingering sfc boundaries as the combination of increasing heat/humidity with a lingering cold pool aloft will allow for strong destabilization to occur. Increased PoPs through the day to account for this as any storms that do manage to develop could pretty easily become strong to severe.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
330 AM Update... Issued an Extreme Heat Watch for south-central NH for Monday and Tuesday. Issued an Extreme Heat Watch for interior western ME for Tuesday.

1055 PM Update...No significant changes in the latest NBM guidance regarding the period of hot and humid conditions Sunday night through Tuesday. Temperatures will trend down into the 80s on Wednesday and 70s on Thursday as high pressure builds into eastern Canada and a stationary front settles near southern New England. This front will bring chances for showers during the second half of next week.

Previously...

Pattern Overview: The long term period will be dominated by a ridge of high pressure building over the eastern United States.
Toward the end of the long term period global models suggest more unsettled weather as the ridge breaks down and the pattern becomes more influenced by a northern stream trough.

Impacts and Key Messages: * Dangerous heat and humidity is expected early next week with heat index values around 100F.

Details:

Monday and Tuesday: This is the period to watch as we will see some early season heat and humidity that will push well into advisory criteria and toward extreme heat thresholds. Dewpoints will remain in the upper 60s and near 70 in many places under a substantial ridge of high pressure that will be building over the eastern United States (ensembles continue to advertise 500 mb heights approaching 600 dm over the Northeast) which will amount to heat index values in the upper 90s to near 100F during the afternoon hours. Our saving grace that is keeping us from slam dunk extreme heat is that Monday flow turns northwesterly which looks to cap the dewpoints around 70 and thusly cap the heat indices in the upper 90s to around 100 for most of the area. This bears watching as just a degree or two uptick in dewpoints and/or temperatures will pump up the heat indices.
With that being said, this is still dangerous heat and humidity, and folks should be well prepared if they are planning outdoor activities. It is also worth noting that nighttime apparent temperatures are going to remain warm Monday night (in the low 70s), so folks should prepare for that as well. Please reference the climate section below for information on potential for high temperature records to be set.

A cold front will be on approach Tuesday and depending on timing this would touch off some showers and thunderstorms as it moves through. Another point of uncertainty is how far south the front makes it. At this moment it seems like areas north of the mountains have the best chance of seeing relief from the heat Tuesday night with areas to the south seeing temperatures in the upper 60s and low 70s linger through the night.

Wednesday-Friday: Wednesday will be warm as the region remains firmly under the ridge, but the aforementioned cold front would bring dewpoints down making for a noticeably less humid and oppressive day. The latest guidance suggests a more unsettled pattern late week as the ridge begins to break down and we get some influence from a northern stream trough. Models can sometimes be optimistic on the speed at which fronts come through and ridges break down, so some heat lingering into Wednesday in southern zones is not out of the question.

AVIATION /14Z SATURDAY THROUGH WEDNESDAY/
Short Term...Outside of any patchy valley FG through 12Z this morning VFR conditions will prevail today with light southerly flow of 5-15 kts. An area of showers and thunderstorms is likely after midnight tonight through around 14Z Sunday and this could result in some restrictions along with some low level wind shear. Mainly VFR is then likely later Sunday but a few additional showers/storms are possible.

Long Term...VFR will prevail through Wednesday.
Thunderstorms are possible again Tuesday night, but uncertainty remains in their extent.

MARINE
Short Term...High pressure moves over the waters today into tonight with generally light winds and fair seas. A few showers and storms are possible early Sunday morning with locally higher winds possible. Southwesterly winds will increase later Sunday with gusts across the outer waters approaching 30 kts with seas of 2-4 ft.

Long Term...Afternoon seabreezes will develop each day as significant heat is expected over the land.

CLIMATE
Anomalously high pressure will allow for dangerous heat and humidity to build into the region. This heat could potentially be record breaking for Monday (6/23) and Tuesday (6/24). Below are the records for our climate sites.

Site Record June 23rd Record June 24th

Portland Jetport 91 (1983) 93 (1976)
Augusta 89 (1999) 93 (1963)
Concord 94 (2020) 95 (1980)

GYX WATCHES/WARNINGS/ADVISORIES
ME...Extreme Heat Watch from Tuesday morning through Tuesday evening for MEZ012>014-018>022-033.
Heat Advisory from 11 AM to 8 PM EDT Sunday for MEZ018-023.
Beach Hazards Statement until 8 PM EDT this evening for MEZ024>028.
NH...Heat Advisory from 11 AM to 8 PM EDT Sunday for NHZ007-008- 010>015.
Extreme Heat Watch from Monday morning through Tuesday evening for NHZ005>013-015.
MARINE...Small Craft Advisory from 7 AM to 8 PM EDT Sunday for ANZ150- 152-154.