Area Forecast Discussion
Issued by NWS Portland, ME

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KGYX 170756 AFDGYX Area Forecast Discussion National Weather Service Gray ME 356 AM EDT Thu Aug 17 2017 .SYNOPSIS...
-- Changed Discussion --
High pressure settles into New England today with dry weather and seasonable temperatures. On Friday night...a warm front associated with low pressure over the Great Lakes will bring an area of rainfall to the Northeast. The best chances for a significant rainfall look to be farther south. Saturday should bring a break in precipitation until the cold front swings through the region. High pressure will build back into the region Sunday into early next week with warming temperatures.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
High pressure will move over the region today. Northwesterly flow will continue this morning as the strong upper low to our northeast provides a pressure gradient through the region. This will prevent any seabreeze from forming along the coast. Additionally a few gusts to 20mph are again possible. Temperatures will remain seasonable with highs near 80 south.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
-- Changed Discussion --
Tonight look for the high pressure to begin to shift eastwards as the next system moves out of the Great Lakes. Skies should remain mostly clear overnight through the eastern portion of the area with clouds approaching in the west. Increasing humidity as a warm front lifts north will keep low temperatures milder. Friday morning rain will move in as low pressure pushes eastward. This rain will spread from west to east across the area during the day on Friday. With southerly flow coming up out of the tropics and high precipitable water values, heavy rain is possible within the convective showers
-- End Changed Discussion --
&& .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
-- Changed Discussion --
Low pressure lifting into Canada will continue to push a warm front towards Nrn New England Fri night. Model guidance suggests this front will have trouble lifting thru the forecast area...so will tend towards more of an occlusion with time. The best LLJ forcing and rainfall potential looks to be Fri night...where Srn zones near the warm front could see a welcomed precip event. The NAM forcing is a little more intense and sharper...leading to a shorter duration rainfall. The GFS forecast soundings are longer duration 25 kt SSW LLJ that bring over a half inch to coastal zones. The GFS forecast resembles the latest ECMWF as well...so I will continue the heaviest precip near the coast overnight. After the occlusion it will be warmer Sat as the low level stable air is cleaned out. The initially clear dry slot will give way to afternoon clouds and scattered showers or storms ahead of the s/wv trof axis. The timing of the trof appears to be favoring Sat night...so not all that favorable for a focused line of convection. So for now I will keep chance to slight chance PoP in the forecast for Sat. I cannot rule out rain...but it also does not look like a widespread rain. After the trof passage a flat ridge looks to build into the area...though deep SW flow will be feeding into it. This should allow some warmer temps to work back into the region with time heading into midweek. The next trof will cross the area around the Wed time frame.
-- End Changed Discussion --
&& .AVIATION /07Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
Short Term...VFR will continue across the area through late tonight with just a chance for morning valley fog in the Connecticut River valley. Increasing clouds ahead of the approaching system will eventually result in ceilings decreasing and MVFR conditions moving in from West to east during Friday afternoon. Friday night IFR in rain and fog is possible. Long Term...Areas of IFR conditions possible Fri night into Sat as warm front/occlusion lifts into the forecast area. Into Sat morning LLJ forcing will bring a round of steadier precip to coastal zones...and this is probably the best window for IFR or lower conditions. Until the cold front sweeps thru the region late Sat...SHRA and/or an isolated TSRA are possible though generally VFR conditions will prevail. VFR conditions continue into Mon.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
Short Term...Long period swell from Hurricane Gert is starting to arrive in midcoast maine. Swell of 7-8ft with period around 12-14 seconds will provide a powerful pull and may result in increased rip current risk. A high surf advisory remains in effect through tonight for the midcoast and a small craft for hazardous seas for the adjacent ocean waters. In the bays sheltering will prevent any large swell while the southern Maine and New Hampshire coast are too east facing to be affected by the more southerly swell. After the swell decreases tonight expect a period of calm conditions on the waters before seas and winds begin to build as the next low moves through Friday night. Long Term...Winds and seas build in response to a LLJ lifting across the waters with the warm front. Given the WAA over the relatively cooler water...wind gusts look to be marginally close to SCA thresholds. More likely seas build to 5 ft on the outer waters for a time Sat. The next chance for SCA conditions will be closer to midweek...ahead of the next cold front.
-- End Changed Discussion --
&& .GYX WATCHES/WARNINGS/ADVISORIES... ME...High Surf Advisory until 8 PM EDT this evening for MEZ025>027. NH...None. MARINE...Small Craft Advisory for hazardous seas until 8 PM EDT this evening for ANZ150-152. && $$ NEAR TERM...Curtis SHORT TERM...Curtis LONG TERM...Legro AVIATION...Curtis/Legro MARINE...Curtis/Legro

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.