Area Forecast Discussion
Issued by NWS Portland, ME

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212 FXUS61 KGYX 221535 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1135 AM EDT SUN MAY 22 2016 .SYNOPSIS... A weak front will stall near the international border today...while low pressure drifts slowly northward through the Gulf of Maine today and early tonight. The interaction of these two disturbances will keep our weather unsettled today with abundant cloud cover and scattered showers. Somewhat drier air will filter into the area tonight into Monday on a northerly flow. Low pressure will affect the region again on Tuesday with showers and perhaps a few thunderstorms. Ridging begins to build on Wed but onshore flow may keep a good portion of our area significantly cooler Friday and Saturday than areas further south and west. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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---1130am update--- Showers in place this morning just off the coast. The mountains have been getting a little bit more sun today than originally expected. This should help to destabilize the boundary layer in that area. Have just started to see some small cells begin to pop up along the Canadian border. Will update forecast to increase chance of precipitation and thunderstorms over the northern mountains. HRRR seems to be doing a good job of picking up on the subtle issues in that area and have relied fairly heavily on it for the afternoon forecast. It is showing the best chance for thunderstorms to begin around 18z and continue through about 22z... as we would expect. Have also adjusted temperatures a little bit to account for the additional sunshine. ---905am update--- Scattered showers in place over portions of the CWA this morning as expected. Expect precipitation to be spotty at best today. Have made minor adjustments to temperatures to account for current trends. Otherwise... no major changes expected. 625 AM...minor ESTF update to reflect the current mesonet and radar trends in near term grids. PREV DISC... At 06z...a weak cold front extended from the rooftop of Maine into southeast Quebec Province. a 1004 millibar low was centered offshore of the DELMARVA region. For today...the weak cold front will stall near the international border while the offshore low drifts slowly northward into the Gulf of Maine. The upper trough axis was centered to our west on latest GOES imagery and will drift overhead today while closing off vicinity of the DELMARVA region by tonight. For today and early tonight...the forecast area will be sandwiched between these two systems with abundant cloud cover and scattered showers. Highs today should be mainly in the 60s.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... For tonight...drier air will begin to filter into the area on a northerly flow with clearing spreading southward from the mountains and foothills onto the coastal plain with any shower activity ending during the evening hours. lows will be mainly in the 40s with a few lower 50s for southern and coastal sections. On Monday...we`ll see partly sunny skies north and increasing clouds southern and coastal sections as the upper low begins to drift northward towards New England. any shower activity should be confined to the southern third of New Hampshire and adjacent southwest Maine. Highs will be in the lower and mid 70s...except in the 60s along the coast in an onshore breeze. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Stacked low pressure off the Mid Atlantic coast Monday evening will move northward Monday night and Tuesday and bring the likelihood of showers to our region. With cold temperatures aloft a few thunderstorms will be possible owing to steepening lapse rates. Thereafter, deep layer ridging looks to build across the northeast states Wed through the weekend. Increasing heat and humidity won`t be far away. However, backdoor front and/or general onshore flow north of a weak warm front may indeed keep our region (especially in Maine) significantly cooler during the late week and weekend. Weak short wave troughs moving through the flow during that time may spark scattered showers and thunderstorms. There will be a fairly thin line between summer arriving here and onshore flow keeping things cool and cloudy. The 00z ECMWF keeps much of Maine and portions of NH in the 50s and 60s over the next weekend which isn`t a good sign. Such is the way spring oftentimes goes here in northern New England. The best chance of late week and weekend heat will be across southern NH. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/... Short Term /through Monday/...VFR...with brief lcl mvfr psbl today in -shra. Long Term...MVFR likely develops Mon night and Tue in showers. Improvement is foreseen Wed through Thu. && .MARINE... Short term /through Monday/...winds will shift into the Northeast as the surface low drifts northward through the gulf of Maine late today and tonight. Winds will increase and seas will build with marginal Small Craft conditions expected outside the bays tonight into the day on Monday. Long term...Winds and seas are generally expected to remain below small craft thresholds Monday night through much of the upcoming week. Perhaps some occasional 5-footers on the ocean waters. && .FIRE WEATHER... cooler temperatures and moderate humidity levels are expected today and Monday with good relative humidity recovery tonight. An upper level low is expected to bring cool unsettled weather to the area for the mid week period. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory from 11 PM this evening to 6 PM EDT Monday for ANZ150-152-154. && $$ Pohl

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