Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 011318 AFDGYX Area Forecast Discussion National Weather Service Gray ME 918 AM EDT Mon Jun 1 2020 .SYNOPSIS... High pressure will bring cool and mostly dry weather today. A weak upper level disturbance will bring the chance for showers Tuesday night and Wednesday. Some warmer air spills into the area for the last half of the week, but another cold front this weekend brings a return to cooler weather. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 917 AM Update... Minor update to match latest observational trends in temperatures and sky conditions. 615 AM Update... Freeze and frost headlines have been dropped as temperatures come up this morning in strong June sunlight. Temperatures should warm quickly in the dry airmass evident on last night`s KGYX sounding. Made minor changes to the forecast package at this time. Previous discussion... In the near term, a deep trough will move east of northern New England, putting the region in SE flow aloft. This will afford short wave energy to dive SE through the area. A couple different ribbons of energy will bring chances of rain to the area through Tuesday. At the surface, weak boundaries will be manufactured at best. This morning, low RH and calm winds have allowed for freezing or near-freezing readings across northern and central areas of NH and ME. This morning after the freeze or frost advisories expire, the drier airmass will support a quick warm-up into the mid 50s north to mid 60s south. This is a few to several degrees lower than normal for this time of year. Skies will be partly to mostly cloudy today with light to slightly gusty NW winds. There may be a few showers across the area resulting in minimal QPF amounts. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... Tonight, another night of calm winds and low dewpoints may result in readings around the mid 30s north to the lower to mid 40s south. On Tuesday, temperatures will be a few degrees warmer than today, with highs in the mid 60s north to upper 60s/lower 70s south. Skies will gradually become cloudier as the day goes on with a short wave trough and increasing PWATs. Precipitation will be scattered ahead of a warm front, but again not expecting much QPF. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... June started out on a frosty note this morning as we sit beneath a cold upper trough with air flowing straight out of the Arctic. This trough moves east with time where it sharpens into a full fledged low which loops back in through the Maritimes and into northeast Canada. Meanwhile out west our next warm bubble is brewing in the desert Southwest where an upper ridge is building, with this warm air gaining moisture over the Great Plains as it heads northward. Eventually some of this warmth and moisture spills around the top of the ridge and into our area from the west later in the week. However, that pesky low over eastern Canada will actually retrograde far enough west to dislodge another shot of cooler air out of the Arctic for this weekend, though not as cold as the current one! We begin the Long Term forecast period with Tuesday night when a series of two shortwave troughs pass through the region in a little more than 24 hours. The first is currently a rather sharp trough over Alberta and will round the very top of the ridge with its remnants passing through our area Tuesday night. This will bring a chance of showers, but probably not a widespread or significant rainfall. Being on the downstream side of the ridge it`s a bit unclear where exactly any of the remnant showers will track, however there seems to be some consensus that the southwestern part of our area will be favored. The next wave is quick on its heals for Wednesday, this time tracking a bit further south around the top of the ridge and able to bring with it some of that warmth and moisture. It seems like shower activity starts back up again late in the day Wednesday, with the best chance of showers tracking across southern New Hampshire. Some more substantial rainfall is possible with this since it has a better moisture connection, however, there`s still a good deal of uncertainty on the location of where the axis of rainfall will be. Some models keep this south of our area. By Thursday morning any lingering showers will have departed to the east leaving a dry day with warmer temperatures. We will be in a roughly zonal flow aloft to the south of the upper low in northeast Canada and downstream of the southwestern US ridge. Expect temperatures about 5 or 10 degrees above normal Thursday and Friday. The next wave tracks across the top of the ridge through southern Canada and moves quickly through the zonal flow into New England on Friday. It will drag a cold front along with it. There will be another chance of rain with the frontal passage, and we cannot rule out some thunderstorms as well depending on how all the ingredients of moisture, lift, and instability line up in time and space. At this time it seems the best chance of thunderstorms will be further north in the Saint Lawrence Valley of Quebec on Friday, with some of these drifting into our area during the evening. The front drops south through New England and delivers cool and dry air for the last half of the weekend and into next week. && .AVIATION /13Z MONDAY THROUGH FRIDAY/... Short Term...A nice aviation flying day today with ceilings staying well above MVFR in any stray light rain shower that could pass through the area. No significant impacts to aviation operations through tonight. Long Term...Could see some MVFR showers Tuesday night and again Wednesday evening as two waves of energy track quickly across the area. VFR conditions are expected for all on Thursday and Friday. && .MARINE... Short Term...High pressure in control over the coastal waters today with winds shifting to the SW and remaining well below SCA conditions. Long Term...Southwest flow continues through Wednesday when a weak low pressure system drags a brief frontal boundary through. The southwest flow quickly returns and remains rather light through the end of the week. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...Schroeter SHORT TERM...Hanes LONG TERM...Kimble AVIATION... MARINE...

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