944 FXUS61 KGYX 160637 AFDGYX Area Forecast Discussion National Weather Service Gray ME 237 AM EDT Sun Oct 16 2022 .SYNOPSIS... Mostly dry weather is expected through the rest of the weekend with frontal boundaries pushing east of the area and high pressure moving overhead Sunday. A frontal system approaches from the Great Lakes late Sunday night and Monday bringing a soaking rain into Tuesday. Cooler and dry weather is expected behind this system through the end of next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... 230 am update...Added a dense fog advisory for midcoast area due to trapped low level moisture causing reduced visibilities. Some drier air is working its way in from the west, which may erode some of the existing dense fog before sunrise, but most of the advisory area will see areas of dense fog until it starts to lift after daybreak. Monitoring portions of S Oxford and interior Cumberland for possible development, but drier air seems to be keeping things spotty at this time. Previously... A highly amplified 500 mb pattern remains in place across North America through the rest of the weekend with a deep trough over Hudson Bay extending southward through the Ohio Valley. This trough will make little if any progress eastward over the next 36 to 48 hours. A north to south stationary boundary across central and eastern Maine has led to isolated showers to moving ashore along the Mid Coast into the Capital District with latest hi res guidance suggesting these will dissipate prior to sunset. Otherwise, the trough will remain far enough to the west of the area limiting precipitation chances through the rest of the weekend. Latest satellite imagery shows marine stratus/fog along and offshore of the Mid Coast with the latest HREF suggesting this will bring patchy fog to the Mid Coast and portions of interior central Maine tonight. How far inland and the western extent of this fog potential remains somewhat in question as the NamNest brings reduced visibility from fog all the way to the foothills back to the ME/NH border while the HRRR shows little inland penetration of fog. Have tried to find the middle ground between these solutions for fog tonight as well as putting some patchy fog in the CT Valley late tonight. Otherwise, skies will be partly to mostly clear with lows in the 30s north to 40s south. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... A dry cold front will approach from the west late tonight and crosses the area Sunday morning. Not expecting much in the way of precipitation with this front with the main sensible weather impact being a slight drop in dewpoints and high temperatures running a few degrees lower than today. After any morning fog, skies will turn mostly sunny through late morning before turning partly sunny in the afternoon. Highs will range from the mid 50s north to mid 60s south. Despite the lowering of dewpoints from the cold frontal passage, onshore flow will again bring the threat of marine stratus and patchy fog along the coastal plain of Maine into southeast NH Sunday night. Clouds will start to increase late in the night as low pressure starts to take shape over the Great Lakes with a warm front extending into southern New England. There will also be potential for fog within sheltered interior valleys such as the CT Valley. Lows Sunday night will range from the 30s north to mid 40s south. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... Overview: Trofing prevails in the extended thru the work week. The slow progression of the pattern will lead to a gradual step down in temps. The best chance for precip will be early in the week. Impacts: The main concern will be QPF as the last event has left rivers running high and soil saturated. While the heaviest QPF looks to be east of the forecast area...a shift westward would be cause for concern that rivers make another run above action stage...especially for western ME. Late in the week will also feature colder overnight temps...and frost/freeze conditions are possible just before the season comes to an end. Forecast Details: Weather will be more active to start the period than ending it. Trof axis will remain over the Great Lakes and leave the Northeast in the WAA portion of the flow. A series of S/WV trofs will pass thru the flow and lead to what looks like two rounds of higher PoP. One on Mon look more warm frontal in nature and showery. The follow up wave is currently modeled to be the stronger of the two with a more robust connection to deep moisture. EFI and ensemble guidance suggest the highest QPF threat is east of the forecast area and despite the time range of the event there is good agreement between suites. Generally looking at mean QPF less than an inch across most of the forecast area...save for parts of the Kennebec River Valley and Penobscot Bay region. After Tue there may be showers...mainly in the mtns...but little QPF on consequence. Temps will be a secondary focus as much colder air dumps into the CONUS. At this time the colder air looks to maximize west and then south of the forecast area...as we remain largely in the southwest flow portion of the upper trof. While colder air will eventually make it here by late in the week...it will be more modified by then. It will introduce a couple nights of widespread 30s however...and with the frost/freeze program still active thru the 21st there may be some need for headlines. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... Short Term...Dense fog showing up at airports along the coastal plains and midcoast this morning. Expect fog to lift after daybreak, but some potential exists for development just offshore that could drift back towards PWM/RKD later today. Otherwise, localized valley fog at MVFR levels with a few ceilings around 200-300' this morning in NH. After morning fog dissipates, terminals will be VFR through the day. Winds remain light despite a weak and dry cold front moving through the region this morning. Some mid/upper clouds will drift in later today, with some clearing overnight in the east. Long Term...Expecting conditions to deteriorate Mon as initial wave of precip approaches. Low clouds in addition to the SHRA will bring periods of IFR conditions thru Tue...especially across western ME. As southerly flow aloft increases Tue there may also be a period of LLWS for ME terminals. VFR conditions will return Wed and without a significant period of high pressure it will be difficult to pin down any potential impacts from valley fog despite recent wet weather. && .MARINE... Short Term...Latest buoy observations show seas 5 to 7 feet outside of the bays, with guidance keeping seas to at least 5 ft through 09Z. Have extended the SCA for seas to 5 ft through 09Z with winds and seas then remaining below SCA thresholds through Sunday night. Long Term...It is getting to be that time of year when SCA conditions become more likely than not. Starting Mon thru the end of the week looks like a period of SCA to near-SCA conditions. While at this time winds/gusts do not appear overly strong...the persistent flow direction may keep seas near 5 ft outside of the bays into Thu/Fri. There may also be areas of fog that develop on the waters ahead of the precip early in the week...but confidence is too low to include in the forecast at this time. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Dense Fog Advisory until 9 AM EDT this morning for MEZ020>022- 025>028. NH...None. MARINE...Small Craft Advisory until 5 AM EDT early this morning for ANZ150-152-154. && $$ SYNOPSIS... NEAR TERM...Casey SHORT TERM...Schroeter LONG TERM...Legro AVIATION... MARINE...