textproduct: Gray - Portland

WHAT HAS CHANGED

The well advertised nor'easter will continue bringing periods of soaking rain, gusty northeast winds, and dangerous marine conditions through Monday. No major changes for this forecast package.

KEY MESSAGES

1. Dangerous marine conditions continue with large breaking waves and a high risk for rip currents. Splash-over and minor coastal flooding are through the high tide cycle tonight and possibly Monday afternoon.

2. Widespread beneficial rain continues through Monday for areas mainly south of the mountains. Gusty winds also continue through Monday but will be gradually diminishing.

3. After the nor'easter moves away on Tuesday, conditions turn warmer and drier for the second half of next week.

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

The nor'easter has stalled near the coast of New Jersey as expected and will continue to remain nearly stationary until Monday morning. The low will then gradually fill in and weaken as it slowly moves across southern New England the rest of Monday through Tuesday.

For our area, storm surge values of 1.0 to 1.5 feet remain on track. While total water level forecasts come up just short of minor flood stage, the Coastal Flood Advisory remains for large wave action. Large near shore waves will bring ample splash over that will bring debris onto vulnerable coastal roadways through at least tonight's high tide cycle. In addition, dune erosion is expected and the most vulnerable locations will see the potential for some inundation.

Hazardous conditions at the beaches and over the waters continue through at least tonight. Near shore waves of 10 to 13 feet continue, with only a gradual decrease in height late today through Monday. The High Surf Advisory that runs through this afternoon remains unchanged to cover the hazardous conditions from large waves and strong rip currents. It is important to note that the long duration of a long fetch will create opportunities for sneaker waves that will be larger embedded waves in a set and have potential to run farther into shore. Therefore, extra caution is encouraged for those venturing to the beach to observed the surf and avoid rock outcrops and jetties.

KEY MESSAGE 2 DESCRIPTION...

As the breadth of the nor'easter increases, bands of showers and steady rain (some heavy at times) will continue to rotate onshore this afternoon and tonight with a rumble of thunder not completely out of the question. The most beneficial rainfall is expected across southern NH and coastal Maine. Further inland, the dry high pressure system to the north will occasionally ridge southward which will limit rainfall amounts, especially this afternoon and evening.

It will remain quite breezy through Monday, but winds will gradually be decreasing. Southeastern New Hampshire and coastal Maine will continue to see the highest gusts, mainly in the 25 to 35 mph range. However, we could see a few gusts to 40 mph early this afternoon over far southeast New Hampshire. The low- level jet will begin a weakening process by later this afternoon, so peak SFC winds should decrease by this evening into Monday.

Not much has changed regarding rain totals through Monday. Areas south of the mountains and along the coast should see a another 1 to 2 inches of rain with locally higher amounts over far southeast New Hampshire and far southwest Maine. Here, localized totals up to 4 inches will be possible through Monday. CAMs suggest that precipitation will likely come in waves with a convective component. Therefore, a stray bolt of lightning may not be impossible along the coast and over the waters. Embedded downpours will also be possible with P-wats in the 90th percentile or greater for this time of year. While most of the precipitation will start to taper off this evening and tonight, the upper low will move overhead on Tuesday which may lead to some lingering areas of light rain.

KEY MESSAGE 3 DESCRIPTION...

After the nor'easter moves offshore, the 500mb pattern looks to favor the development of a ridge over the eastern US. With high pressure setting up south of New England, moderating temperatures are expected for mid to late week with mainly dry conditions. Some very weak instability could allow for a stray shower to generate on Wednesday or Thursday, but most should remain dry.

Rain chances are a little higher on Friday, as a cold front is poised to move southward across New England. However rain chances are likely to remain in the slight-chance category, as the front is very weak and any instability will have to overcome a modest subsidence layer. High pressure then looks to dominate the weather over the weekend.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Through Monday...Widespread IFR to MVFR through Monday evening, especially near the coast in rain. However, periods of improvement are possible outside of rain banding. Coastal terminals may see northeast surface gusts of 35 kt or more today, especially towards PSM.

Outlook:

Tuesday: Conditions gradually improving to at least MVFR.

Wednesday and Thursday: VFR expected.

Friday: VFR expected most places. Occl showers could lead to brief periods of MVFR at HIE.

MARINE

Nor'easter continues to bring gusty winds and high seas to the coastal waters. Marine conditions should gradually improve today and tonight but a Gale Warning remains in effect through early evening for all waters but the bays. A strong SCA remains in effect for the bays. SCA conditions will linger into Tuesday evening before dropping below thresholds.

After the passage of the nor'easter on Tuesday, winds and seas will continue to subside as high pressure moves in. Waves likely fall below 5ft by Wednesday. High pressure then brings mainly fair conditions for midweek, with the next cold front then possible on Friday.

GYX WATCHES/WARNINGS/ADVISORIES

ME...Coastal Flood Advisory until 3 AM EDT Monday for MEZ023. High Surf Advisory until 8 PM EDT this evening for MEZ023>027. NH...Coastal Flood Advisory until 3 AM EDT Monday for NHZ014. High Surf Advisory until 8 PM EDT this evening for NHZ014. MARINE...Gale Warning until 8 PM EDT this evening for ANZ150-152-154- 180-182-184. Small Craft Advisory until 8 AM EDT Monday for ANZ151-153.