Area Forecast Discussion
Issued by NWS Portland, ME

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965 FXUS61 KGYX 100108 AFDGYX Area Forecast Discussion National Weather Service Gray ME 908 PM EDT Sun Jun 9 2024 .SYNOPSIS... Somewhat unsettled daytime weather is expected to continue into Tuesday as upper level low pressure lingers overhead. Warmer and drier weather is expected Wednesday and Thursday with a cold frontal passage possible Friday or Saturday with more showers and thunderstorms. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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9 PM UPDATE...Current 00Z observations are running a little cooler than forecast. Opted to interpolate observations and drop overnight temperatures by a degree. Otherwise current forecast is on track, with no adjustments needed elsewhere. 4 PM DISCUSSION...A short wave trough and weakening low pressure continue to swing through the area this afternoon with the steady shield of rain moving offshore at this time. Partial clearing will continue to take place late this afternoon and early evening with weak surface-based instability developing beneath the upper low. This will likely aid in scattered convective showers for the balance of the afternoon, with some thunder possible. These will weaken and dissipate with the loss of heating this evening. However, BKN clouds will continue from time to time overnight. There should be enough of a gradient to preclude widespread dense fog, but we do expect at least patchy where conditions go clear and near-calm. Low temperatures a blend of the MOS products.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/... Upper level low pressure will continue to wobble over northern New England on Monday. A fair start will gradually lead to increasing boundary layer CU and then convective showers, with a possible thunderstorm, especially in the mountains. Highs in the 60s in the mountains, 70s elsewhere. Variably cloudy Monday night with upper low remaining overhead, but showery weather ends in the evening with loss of diurnal heating. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Overview: High pressure approaches from the west Tuesday with some showers possible, mainly across the mountains. This high will pass to the south into Wed/Thurs as lift remains limited for possible shower coverage. Low pressure tracking across Quebec will remain north Friday, but bring warm/cold fronts into the region which will aid in development of more widespread showers or thunderstorms late week. Temperatures mild through midweek, increasing late week. Details: Tuesday and Wednesday will both be similar days with cool NW to W flow moderating temperatures and little lift to speak of. But, there will be plenty of moisture through the column for cloud cover and the chance for showers where daytime heating/convergence can muster weak convection. Guidance is actually quite spread out for QPF both days, but have currently limited this to the mountains on Tuesday. This seems to be a good bet considering weak onshore flow to the SE and incoming northwesterly flow on the other side. Shear and storm motion are weak, so these may stay put over summits with little movement. Think the same could be in store for Wednesday, but drier air will be at the surface to limit shower coverage further. Later in the week is a bit more uncertain, but warmer. Thursday may be dry, but there will also be a warm front in the region that could focus some shower development late in the day. The positioning of this will be determined by the parent low that will be tracking across Quebec late week. This leads into Friday when conditions may be more primed for thunderstorms when the low nears and pulls a cold front through during the day or later in the evening. Will keep a wide window here given the uncertainties, but CSU MLP for severe has been highlighting portions of the area fairly consistently Friday. Should the low move through as scheduled in the Friday timeframe, a pleasant weekend may be in store with drier conditions and temperatures in the upper 70s to around 80. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... Short Term... Improvement is foreseen for late this afternoon and evening as low pressure moves away from the region. VFR conditions are expected tonight except for patchy fog. A few convective showers and storms will occur again on Monday, and this would be mainly in the afternoon and across the northern mountains. Long Term...Some lowered ceilings will be possible across northern NH and far western ME Tuesday, trending VFR Wednesday. The airmass mid week could support some low stratus or fog over the coastal waters, thus some terminals such as RKD or PWM could be impacted at times. && .MARINE... Short Term...Southwest winds of 10 to 15 kt with gusts around 20 kt (a few around 25 kt) will continue tonight, with more of a turn to the north Monday night. Seas remain 3 to 4 feet. Long Term...Light SSE flow Tues-Thurs with wave heights 1 to 2 ft as broad low pressure passes to the north with another surface low to the south. High pressure passes south mid to late week. This will keep moisture in the region that could develop marine status or fog through much of the week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ NEAR TERM...Cempa/Palmer SHORT TERM...Ekster LONG TERM...Cornwell