Cape Elizabeth ME to Merrimack River MA Marine Forecast
|Rest Of Tonight...S Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas Around 3 Ft. Areas Of Fog. Vsby 1 To 3 Nm.|
|Mon...S Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 3 To 4 Ft. Areas Of Fog In The Morning With Vsby 1 To 3 Nm.|
|Mon Night...S Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 3 To 4 Ft. Areas Of Fog. Vsby Variable To Less Than One Quarter Nm.|
|Tue...S Winds 10 To 15 Kt. Seas 3 To 5 Ft. Areas Of Fog In The Morning. Areas Of Fog In The Afternoon. Vsby Variable To Less Than One Quarter Nm, Increasing To 1 To 3 Nm In The Afternoon.|
|Tue Night...S Winds 10 To 15 Kt With Gusts Up To 20 Kt. Seas 3 To 5 Ft. Scattered Showers In The Evening, Then Showers Likely After Midnight. Areas Of Fog After Midnight. Vsby 1 To 3 Nm.|
|Wed...S Winds 10 To 20 Kt, Becoming Around 15 Kt In The Afternoon. Seas 5 To 8 Ft. Areas Of Fog In The Morning. Scattered Tstms. Rain. Vsby 1 To 3 Nm In The Morning.|
|Wed Night...Sw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 4 To 7 Ft. Rain Likely. Vsby 1 To 3 Nm After Midnight.|
|Thu...Sw Winds 10 To 15 Kt. Seas 4 To 7 Ft. Rain Likely In The Morning, Then Scattered Showers In The Afternoon. Vsby 1 To 3 Nm In The Morning.|
|Thu Night...Sw Winds Around 10 Kt. Seas 4 To 6 Ft. Scattered Showers In The Evening.|
|Fri...Sw Winds 5 To 10 Kt. Seas 3 To 5 Ft.|
|Fri Night...S Winds 5 To 10 Kt, Becoming W After Midnight. Seas 3 To 5 Ft. Winds And Seas Higher In And Near Tstms.|
| Area Forecast Discussion|
National Weather Service Gray ME
1001pm EDT Sunday September 27 2020
Warm and humid conditions will persist for the first part of the week with chances for showers. More widespread rainfall is expected midweek that will bring some relief to the drought. Cooler and drier weather is expected towards the end of the week.
Near Term - Until 6am Monday Morning
10:00pm Made minor adjustments to forecast low temperatures, sky grids, and wind grids based on recent surface and satellite observations. Still looks like scattered showers will move in from the south beginning around 07Z Monday and persist through at least the first half of the day. Interestingly, visibilities have been improving across the region since earlier this evening and will therefore need to be watched to see if this trend continues. The rest of the forecast remains on track.
715 PM...Updated fog a bit just based on current trends, areas around Pen Bay are getting down below 1 mile, but elsewhere, and mainly along the coast, fog is more patchy with higher vis. Adjusting timing on POPS a bit based on latest HRRR, with showers moving into southern NH shortly after midnight and NE into Me in the pre-dawn hours.
Satellite imagery shows a mix of high and low level clouds over the area and recent webcams show southerly facing beaches in fog, while more easterly facing beaches mostly clear with a fog bank offshore. Farther south there is a notable mesovortex spinning off the DelMarVa coast that is associated with a weak wave of low pressure that will move up the Eastern Seaboard tonight drawing more moisture into the area.
Clouds will thicken and lower this evening with more fog expected for much of the area overnight. The wave of low pressure, with the help of some mid-level support, will bring chances of showers mainly after midnight into Monday morning. Not expecting widespread shower coverage, but with PWATs (Precipitable Waters) approaching 1.75 inches a few areas will be able to receive around 0.25 inches of Quantitative Precipitation Forecast. The best chances for measurable rain will be from the mountains southeastward towards the Mid-Coast. It will be mild tonight with much of the area only dropping into the 60s for low temperatures.
Short Term - 6am Monday Morning Through Monday Night
The weak wave of low pressure will be moving through downeast Maine Monday morning with shower activity diminishing by early afternoon. It will be warm and muggy with mostly cloudy skies. Highs will be in the 70s for most and cooler again along the coast with onshore winds. Monday night will be mild and muggy again with a return of areas of fog for much of the area.
Long Term - Tuesday Through Sunday
Overview: Amplified pattern taking shape across CONUS as we shift to a much more active pattern regionally. Moisture transport from the Gulf of Mexico will support a couple chances of beneficial rainfall.
Impacts: Model guidance is trending towards two main areas of rainfall. While a widespread soaking rain is looking likely at this point...there is a chance that some significant amounts may fall. Flash flood guidance is quite high given the drought conditions...but if the precipitation rates are heavy enough there could be some localized runoff related flooding with dry/compacted ground.
Forecast Details: Trof continues to amplify Tuesday which will allow frontal boundary to begin to stall before reaching the forecast area. For that reason I expect most of Tuesday to remain dry across the area outside of some drizzle and fog near the coast.
Late Tuesday into Wednesday the lead S/WV trough moves into the region and will help force an elongated area of low pressure at the surface moving Nwd along the front. Right entrance region of the upper jet will keep S flow going in the mid levels. This should help to maximize rainfall totals along the S facing slopes. Overall a widespread soaking rain is expected given the high moisture content of the air mass...but the lack of strong forcing mechanism should keep rates generally light to moderate. One thing to watch will be if forcing can parallel the boundary and training of embedded heavier precipitation can start to lead to higher totals.
Both the GFS and ECMWF (European Centre for Medium-Range Weather Forecasts) now are in agreement with upper low at the base of the trough swinging NEwd as an opening but strong S/WV Thu. This supports cyclogenesis along the frontal boundary and another area of potentially significant rainfall moving thru the Northeast. This rainfall could feature enough forcing to be heavy at times. Ensemble guidance remains mixed on the idea...with roughly half of all members of the GEFS and EPS showing a widespread moderate to heavy rainfall event Thu. In light of the increasing odds for this scenario...I have blended the multi-model consensus with raw model guidance to increase PoP to likely across most of the forecasts area Thu.
Low visibility in fog is expected into Monday night. Southerly flow will increase during the day Monday with building seas. SCA (Small Craft Advisory) may be needed late Monday as wind gusts approach 25 kts by late Monday and seas building to 5 feet over the outer waters.
Long Term...S winds are expected to increase to near 25 kt outside of the bays...with seas continuing above 5 ft thru midweek.
NOAA Gray/Portland ME Office - Watches - Warnings - Advisories
ME...None. NH...None. MARINE...None.