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. --276FXUS61 KGYX 152004AFDGYXArea Forecast DiscussionNational Weather Service Gray ME404 PM EDT Thu Aug 15 2024***UPDATED NEAR/SHORT TERM***.SYNOPSIS...
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Thunderstorms are moving through NH this afternoon, with morestorms developing soon. These storms may contain gusty windsand small hail. Storms clear the region late tonight with areasof fog popping up across the region tomorrow morning. Tomorrowshould be drier than today but a few thunderstorms can`t beruled out north of the mountains. Hurricane Ernesto movesparallel to the Gulf of Maine Sunday night bringing high seasand swell to the coast, with no other impacts from Ernestoexpected. The weather after Sunday looks unsettled with showersand storms possible through much of early next week.
-- End Changed Discussion --&&.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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A mature upper-level low over the Canadian Maritimes continuesto bring cooler and moist conditions into NH and ME. Currentobservations shows overcast and temperatures in the 70s acrosswestern Maine with much warmer temperatures observed over theCT river valley. This upper-level low will interact with aright jet-exit region in an environment with 1400J of CAPE andlow-level wind shear, allowing for the development of morestrong thunderstorms this afternoon. Any developing storms willmove south through the evening, with gusty winds and small hailremaining possible with some of the stronger storms thatdevelop. Once the sun sets this evening, energy will be lostquickly and not long after storms will start to fizzle out.The calm winds after the storms tonight will allow for easydevelopment of fog as temperatures cool down within a remnantmoist environment overnight. Areas of fog will overspread theregion tomorrow morning with the aforementioned upper-level lowheading off to sea.
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Maine should expect to see slightly warmer temperaturestomorrow with similar temperatures expected in New Hampshire.Some destabilization around daybreak tomorrow will allow a fewstorms to pop-up north of the mountains. More calm windstomorrow night, within a drier environment than tonight`s willallow for some patchy fog to form tomorrow night, though lessfog than what is expected tonight. Winds will start picking upfrom the south/southeast as a cold front associated with anupper-level low in the Great Lakes approach the region
-- End Changed Discussion --&&.LONG TERM /SATURDAY THROUGH THURSDAY/... At 500 MB, the weekend will start will a small area of ridgingover New England as we sit between upstream and downstreamtrough and Ernesto to our SE. By Monday that trough shifts overthe NE CONUS. And 500 MB flow on the downstream side tightensup a bit as it runs into ridging and absorbs Ernesto to our E,which makes Monday the day with the most dynamic forcing and thebest chance for rain. The trough, and likely associated coldfront swings through on Tuesday, with cooler and less humid airmoving in for the middle of the week. However, will have that500 MB trough lingering, which means a chance for some showers.By late week, should see some sfc ridging move in beneath NWflow aloft.Models seem a little more optimistic about the weekend, giventhe relative ridging overhead. Still cannot rule out a fewSHRA/TSRA, especially if a greater amount of sun leads toincreased instability, although Saturday seems better cappedthan Sunday, so slightly lower chances then. Highs on Saturdaywill be in the upper SS to lows 80, while on Sunday, withbetter onshore flow and more clouds, mainly run in the 75-80range. Itll be more humid with Tds running in the mid to upper60s, and overnight lows in the low to mid 60s.On Monday,, as that upper level trough starts to deepening abit and a wave lifts out of the base of it, will see more in theway of SHRA/TSRA, and it`ll be more cloudy as well. Alsohumidity will be up with tds in the mid 60s N to the upper 60sand low 70s S. Highs will be closer to the mid 70s than 80 onMonday as well. SHRA/TSRA continue into Mon evening, but shouldstart to wane somewhat after midnight, and the cold front maymake into the mtns late so lows range from the upper 50s thereto the low to mid 60s in the S.Tuesday and Wed will be cooler and drier as 950 temps drop below+10C, so highs will generally be in the 70s both days. Thecooler air aloft and the 500 MB trough overhead will be enoughfor scattered daytime showers to develop, and perhaps a coupleTSRA as well. Overnight lows will be more comfortable and rangefrom the low 50s in the mtns to the mid to upper 50s in the S.&&.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
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Short Term...Currently, scattered thunderstorms are ongoing acrosssouthern NH, including CON, MHT, PSM. Storms are just starting todevelop over LEB and HIE, with VFR likely over AUG and RKD. Stormsthis evening will continue to impact airports across NH and PWM.Areas of fog early tomorrow morning will likely bring most sitesdown to LIFR. Most fog tomorrow should mix out by 9 AM. Scatteredstorms tomorrow afternoon may impact HIE, but no other impacts areexpected tomorrow. Patchy fog may return for Thursday morning.Long Term...While VFR is expected to prevail through theweekend, cannot rule out some brief flight restrictions due toSHRA/TSRA and then patch fog at night. Late Sunday night intoMonday could some low stratus and numerous SHRA, plus a fewTSRA, and will likely see MVFR with some periods of IFR throughthe day, with possibly some LIFR into Monday night. Expecting areturn to mainly VFR Tuesday morning.
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Short Term...Light southeasterly flow expected tonight with less than 3ft seas. Showers and thunderstorms this afternoon/evening over theGulf of Maine may impact any marine operations. Thick fog ispossible tomorrow morning over the Gulf, but otherwise tomorrow willfeature light southeasterly flow and 2-3 ft seas. Seas increase alittle tomorrow night and into Saturday morning. No SCAs areexpected over the next 2 days.Long Term...Winds will not be an issue this weekend into earlynext week, but seas will increase, especially on Sunday and peakon Monday in long period swell from Ernesto. Seas away from thecoast could push to almost 10 ft, while near shore waves couldreach to around 6 ft. The seas will begin to subside late Mondaynight and Tuesday.
-- End Changed Discussion --&&.GYX WATCHES/WARNINGS/ADVISORIES...ME...None.NH...None.MARINE...None.&&$$SYNOPSIS...PalmerNEAR TERM...Palmer/ClairSHORT TERM...Palmer/ClairLONG TERM...Cempa