National Weather Service (2024)

Area Forecast Discussion
Issued by NWS Portland, ME

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-- Discussion containing changed information from previous version are highlighted. --305FXUS61 KGYX 071436AFDGYXArea Forecast DiscussionNational Weather Service Gray ME1036 AM EDT Fri Jun 7 2024.SYNOPSIS...An upper low approaches from the west bringing chances ofshowers and few thunderstorms this afternoon and Saturdayafternoon. A second upper low moves over the area Sunday intothe upcoming workweek keeping shower chances going into themiddle of next week.&&.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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1035 AM Update...Scaled back PoPs again as showers only remainin central Maine. Also tried to get a better handle on theclearing in New Hampshire. At the moment much of the state ismostly clear with only the southeast still holding on to clouds,but even there it looks like it will clear in the next hour ortwo. The inherited forecast remains on track with these clearingareas being the focus for thunderstorm development thisafternoon.635 AM Update...Have trimmed back PoPs across much of NH into SWMaine as a band of rain showers has lifted to the north. Havealso prolonged fog in the valleys of western NH based onsatellite trends.Previously...An elongated trough/upper low will remain to the west of NewEngland through today. This system will spread forcing forascent over the forecast area with models suggesting a couplesurface troughs will rotate through late morning into tonight.This will lead to showers and possibly a few thunderstormsdeveloping from early this afternoon into this evening with thebest chances focused in the mountains. However, the 00Z HREFsuggests a few cells could track all the way to the coast.The forecast challenge is how well skies clear and the resultantinstability. As of early this morning much of the area is socked inwith low ceilings and fog, although there are breaks in the cloudsacross far SW NH back across western New England and Upstate NY.Winds look to remain predominantly onshore through the day withcloud cover and the marine influence limiting the instability alongthe coast into central Maine. West to southwest flow develops acrossacross New Hampshire into interior western Maine that will lead toperiods of insolation. CAMs suggest MU CAPE builds to 500-1000 J/kgacross these areas with possibly an axis of higher CAPE near theNH/ME border. Deep layer shear will be quite strong with 0-6 kmshear approaching 60 kts. This magnitude of shear may actually actto squelch updrafts, especially as mid level lapse rates will bepoor around 5C/km. Therefore, the threat for storms to become strongis low. The overall forecast thinking for today is for clouds tolinger longest near coastal and central Maine with a mix of sunclouds across New Hampshire and western Maine. Highs will range fromthe mid 60s across central Maine to the low 80s across southern NH.Much of the area looks to remain precipitation free through mid daywith PoPs increasing early this afternoon through the evening.
-- End Changed Discussion --&&.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...Shower chances will continue through tonight as the upper low makeseastward progress. Light westerly flow looks to push into westernMaine tonight with somewhat drier air moving in by Saturday morning.This should limit fog development tonight with the greatestpotential for fog near the Mid Coast. Lows tonight will drop intothe low to mid 50s.The upper low moves overhead during the day Saturday. This willsteepen mid level lapse rates and likely leads to selfdestructive sunshine as solar heating in the morning leads to CUdeveloping by mid day. This will also lead to some afternoonshowers across the interior towards the Mid Coast where an areaof convergence will help with lift. Saturday will be coolerthan today with highs in the 60s north to 70s south. Steady westto southwest winds will inhibit a sea breeze with coastal areasreaching the same warmth as the interior.&&.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...The overall pattern across the northeast in the extended willconsist of moist cyclonic flow due to upper level low pressurelingering across the northeast US and southeast Canada. Thiswill lead to unsettled weather at times. But at this time itdoes not look like there will be any washouts, just mainlychancy to low likely PoPs for showers and thunderstorms attimes, peaking in the afternoons with diurnal heating. This willbe mainly true Saturday through Monday before a period ofridging takes hold thereafter. Highest PoPs each day are in themountains, with lesser PoPs in southern NH where it could bedry most of the time.Temperatures each day will be in the 70s for most folks, with60s in the mountains. A warming trend will take place Tuesdayand Wednesday with highs returning back into the 80s.&&.AVIATION /15Z FRIDAY THROUGH TUESDAY/...Short Term...IFR/LIFR conditions in low cigs and fog likelypersist until around 12Z for most TAF sites. Conditions thenimprove across interior NH TAF sites with VFR likely by midmorning. Coastal sites and KAUG will likely see IFR to MVFRconditions through this morning with cigs lifting thisafternoon. Scattered SHRA this afternoon may bring briefrestrictions. Coastal sites and KAUG likely see IFR conditionsagain tonight in low cigs while dry air moving into the NH willlimit flight restriction there. VFR likely prevails Saturday,although scattered after SHRA will be possible.Long Term...Outside of scattered showers and an isolatedthunderstorm, or two, ceilings will be mainly VFR throughTuesday. Winds also remain on the lighter side, generally lessthan 10 kt with westerly gusts possibly 20 to 25 KT Saturday andSunday afternoons.&&.MARINE...Short Term...Winds and seas remain below SCA thresholds throughSaturday. Dense marine fog continues this morning and erodesfrom SW to NE this afternoon while the Mid Coast may hang ontofog through tonight. Scattered showers and thunderstormsforming over land may track into the waters before weakeningthis afternoon. Winds eventually turn westerly around Saturdaymorning limiting the fog potential over the waters.Long Term...Conditions hazardous to small craft are notexpected through Tuesday. Seas will generally be 3-4 ft withwinds 10-15 kts with gusts to 20kts.&&.GYX WATCHES/WARNINGS/ADVISORIES...ME...None.NH...None.MARINE...None.&&$$UPDATE...BaronNEAR/SHORT TERM...SchroeterLONG TERM...Ekster