textproduct: Gray - Portland

WHAT HAS CHANGED

No significant changes were noted with this latest forecast package.

KEY MESSAGES

1. Dangerous marine conditions are observed and expected to continue with large breaking waves and a high risk for rip currents. Splash-over and minor coastal flooding are possible for several high tide cycles through late Sunday evening.

2. This nor'easter will also lead to areas of widespread beneficial rain south of the mountains and gusty northeast winds through at least Monday along the coast and southern New Hampshire.

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

DISCUSSION

KEY MESSAGE 1 DESCRIPTION...

A nor'easter centered 185 miles east of DelMarVa will drift NNE towards 40N/70W benchmark through this evening. Models are in agreement that the center of the system will make a decision turn westward towards Long Island and New Jersey tonight into Sunday. The nor'easter will become vertically stacked and start to fill Sunday night and will slowly move across southern New England through Tuesday.

The main take away from recent observations and forecast trends has been a decrease in storm surge. This is primarily a result of the southward trend in the storm track. Storm surge models have trended down and have incorporated this into the latest forecast with surge holding around 1.0 ft, peaking below 1.5 ft. While total water level forecasts come up just short of minor flood stage, have left the Coastal Flood Advisory unchanged. Large near shore waves will bring ample splash over that will bring debris onto vulnerable coastal roadways through at least the next three high tide cycles. 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 are observed and are expected to continue through at least Sunday night. Latest observations show near shore waves pushing 9 feet with an 11 second period with waves offshore near Jeffrey's Ledge at 14 feet with an 11 second period. Waves are expected to increase into this evening and then hold steady through Sunday before subsiding Sunday night. The High Surf Advisory that runs through Sunday 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...

The well advertised nor'easter will continue to drift north for a little bit longer before stalling out somewhere off the coast of New Jersey by early Sunday. We have seen a couple bands of light rain move into the area, gradually moistening the atmosphere from south to north. Gusty winds and precipitation chances will be on the increase through the rest of the day with periods of moderate to heavy rain possible through Monday. Areas south of the mountains and along the coast should see a widespread 1 to 2 inches of rain while the latest HREF guidance suggests a potential for 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 later in the day on Monday, the upper low will move overhead on Tuesday which may lead to some lingering areas of light rain.

Our area will be under a decent pressure gradient with high pressure to the north and the nor'easter to our south but the threat for stronger winds may have backed off just a bit as the low continues to trend further south. Forecast soundings at Portsmouth still suggest we could see some winds in the 40 to 45 knot range at the top of the mixed layer across southeast New Hampshire late Saturday through Sunday morning but available momentum should decreasing north and east. In general, it appears that the strongest gusts will be over portions of southeastern New Hampshire and southwest Maine to around 40 mph. Elsewhere expect breezy northeast winds gusting 25 to 35 mph. While winds will not be overly strong, this will be a rather long duration event. We will likely see the strongest gusts later today through Sunday morning, but breezy conditions will last into at least Monday. Thus, with plenty of leaves on the trees there could be a limited power outage threat, especially along the coast and portions of the interior.

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. In addition to high pressure moving in south of the northeast, this could allow for above average temperatures in the second half of next week. High pressure, while not exactly onto of the region, should keep most places dry. Some very weak instability could allow for a stray shower to generate on Wednesday or Thursday, but most people should stay dry.

Rain chance 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.

AVIATION /18Z SATURDAY THROUGH FRIDAY/

Through 18Z Sunday...Ceilings will be lowering as the day goes on and rain spreads across the region. Terminals likely fall to MVFR categories by late in the afternoon or evening. The one exception may be at HIE and LEB where VFR ceilings hang on until later in the night. Widespread IFR conditions are then likely late at night into Saturday afternoon with heavy rain possible at southern and coastal terminals. North-northeasterly wind gusts will generally be 20-25kts today/tonight with 30 kts possible at coastal terminals. Some enhanced low-level wind shear will be possible over the southern New Hampshire terminals tonight into Sunday morning.

OUTLOOK:

Sunday: Widespread IFR to MVFR likely, especially near the coast in rain. Coastal terminals may see northeast surface gusts of 35 kt or more, especially towards PSM.

Monday: Areas of MVFR or lower in rain/showers. North northeast surface gusts of 25 kt or more possible.

Tuesday: Conditions improving to VFR. A few showers may linger over the mountains.

Wednesday and Thursday: VFR expected.

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

MARINE

Developing nor'easter continues to build winds and seas over the coastal waters. The worst of the marine conditions are expected through tonight. Gale Warning remain in effect for all waters but the bays, with a strong SCA in the bays. Those conditions will last through Sunday before things begin to diminish. SCA conditions will linger into Monday evening before dropping below thresholds.

After the passage of the Nor'easter on Tuesday, winds and seas will diminish as high pressure moves in. Northwesterly winds of 6-10kts are forecast from Wednesday afternoon through Friday. Seas of 2-4ft likely. SCA issuance is not expected.

GYX WATCHES/WARNINGS/ADVISORIES

ME...High Surf Advisory until 8 PM EDT Sunday for MEZ023>027. Coastal Flood Advisory until 11 PM EDT Sunday for MEZ023. NH...High Surf Advisory until 8 PM EDT Sunday for NHZ014. Coastal Flood Advisory until 11 PM EDT Sunday for NHZ014. MARINE...Gale Warning until 8 PM EDT Sunday for ANZ150-152-154-180-182- 184. Small Craft Advisory until 8 AM EDT Monday for ANZ151-153.