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. --049FXUS61 KGYX 100228AFDGYXArea Forecast DiscussionNational Weather Service Gray ME1028 PM EDT Sun Jun 9 2024.SYNOPSIS...Somewhat unsettled daytime weather is expected to continueinto Tuesday as upper level low pressure lingers overhead.Warmer and drier weather is expected Wednesday and Thursdaywith a cold frontal passage possible Friday or Saturday withmore showers and thunderstorms.&&.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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1030 PM...Quick little update to get rid of all the POPs fora few hours, and then reintroduce in the mtns during the pre-dawn as the next wave comes through.9 PM UPDATE...Current 00Z observations are running a littlecooler than forecast. Opted to interpolate observations anddrop overnight temperatures by a degree. Otherwise currentforecast is on track, with no adjustments needed elsewhere.4 PM DISCUSSION...A short wave trough and weakening lowpressure continue to swing through the area this afternoon withthe steady shield of rain moving offshore at this time. Partialclearing will continue to take place late this afternoon andearly evening with weak surface-based instability developingbeneath the upper low. This will likely aid in scatteredconvective showers for the balance of the afternoon, with somethunder possible. These will weaken and dissipate with the lossof heating this evening. However, BKN clouds will continue fromtime to time overnight. There should be enough of a gradient topreclude widespread dense fog, but we do expect at least patchywhere conditions go clear and near-calm. Low temperatures ablend of the MOS products.
-- End Changed Discussion --&&.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/...Upper level low pressure will continue to wobble over northernNew England on Monday. A fair start will gradually lead toincreasing boundary layer CU and then convective showers, with apossible thunderstorm, especially in the mountains. Highs in the60s in the mountains, 70s elsewhere. Variably cloudy Mondaynight with upper low remaining overhead, but showery weatherends in the evening with loss of diurnal heating.&&.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...Overview: High pressure approaches from the west Tuesday withsome showers possible, mainly across the mountains. This highwill pass to the south into Wed/Thurs as lift remains limitedfor possible shower coverage. Low pressure tracking acrossQuebec will remain north Friday, but bring warm/cold fronts intothe region which will aid in development of more widespreadshowers or thunderstorms late week. Temperatures mild throughmidweek, increasing late week.Details: Tuesday and Wednesday will both be similar days withcool NW to W flow moderating temperatures and little lift tospeak of. But, there will be plenty of moisture through thecolumn for cloud cover and the chance for showers where daytimeheating/convergence can muster weak convection. Guidance isactually quite spread out for QPF both days, but have currentlylimited this to the mountains on Tuesday. This seems to be agood bet considering weak onshore flow to the SE and incomingnorthwesterly flow on the other side. Shear and storm motion areweak, so these may stay put over summits with little movement.Think the same could be in store for Wednesday, but drier airwill be at the surface to limit shower coverage further.Later in the week is a bit more uncertain, but warmer. Thursdaymay be dry, but there will also be a warm front in the regionthat could focus some shower development late in the day. Thepositioning of this will be determined by the parent low thatwill be tracking across Quebec late week. This leads into Fridaywhen conditions may be more primed for thunderstorms when thelow nears and pulls a cold front through during the day or laterin the evening. Will keep a wide window here given theuncertainties, but CSU MLP for severe has been highlightingportions of the area fairly consistently Friday. Should the lowmove through as scheduled in the Friday timeframe, a pleasantweekend may be in store with drier conditions and temperaturesin the upper 70s to around 80.&&.AVIATION /03Z MONDAY THROUGH FRIDAY/...Short Term... Improvement is foreseen for late this afternoonand evening as low pressure moves away from the region. VFRconditions are expected tonight except for patchy fog. A fewconvective showers and storms will occur again on Monday, andthis would be mainly in the afternoon and across the northernmountains.Long Term...Some lowered ceilings will be possible acrossnorthern NH and far western ME Tuesday, trending VFR Wednesday.The airmass mid week could support some low stratus or fog overthe coastal waters, thus some terminals such as RKD or PWM couldbe impacted at times.&&.MARINE...Short Term...Southwest winds of 10 to 15 kt with gusts around 20kt (a few around 25 kt) will continue tonight, with more of aturn to the north Monday night. Seas remain 3 to 4 feet.Long Term...Light SSE flow Tues-Thurs with wave heights 1 to 2ft as broad low pressure passes to the north with anothersurface low to the south. High pressure passes south mid to lateweek. This will keep moisture in the region that could developmarine status or fog through much of the week.&&.GYX WATCHES/WARNINGS/ADVISORIES...ME...None.NH...None.MARINE...None.&&$$SYNOPSIS...NEAR TERM...Cempa/Ekster/PalmerSHORT TERM...EksterLONG TERM...CornwellAVIATION...MARINE...