Area Forecast Discussion
Issued by NWS Portland, ME

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481 FXUS61 KGYX 011100 AFDGYX Area Forecast Discussion National Weather Service Gray ME 700 AM EDT Wed May 1 2024 .SYNOPSIS... Drier today but still mainly cloudy and cool in onshore flow. Shower chances return for Thursday. Cloudy skies and onshore winds will favor high temperatures running below normal through the rest of the week. High pressure builds in from the north Friday for mostly fair weather into Saturday. Chances for showers increase Sunday into Monday then warmer temperatures are looking likely for the first part of next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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7 AM...Showers have cleared the CWA to the S, so POPS were lowered for this morning. Otherwise forecast is in good shape as we look forward to another cloudy and cool day, although maybe a bit warmer than Tuesday. Previously...While there has been fairly strong and persistent ridging across the eastern third of the CONUS the last few days and that slowly shifts east over the next few days, it has not done any favors, except going back to Monday. This is because the ope of the ridge has persistently been hammered by weak waves either ejecting 500 Mb closed low over the Canadian prairie or being generated by deep convection over the US plains /sometimes both/. For today, we see one wave that moves that moves E of the CWA, and this allows the ridge to build up a little. This keep the keep the day dry, but the low level onshore flow will keep us cool and generally cloudy. Could see some limited breaks of sun late in the day, especially in the E zones, and also SW NH and maybe the CT valley up to KLEB or so. The downslope will help this areas warm a bit more than everywhere else, but still highs here will only be around 60 or maybe the low 60s. Elsewhere expect highs in the 50s, lower 50s near the coast and mid to upper 50s inland.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Yet another wave moves in from the W tonight and crashes the ridge aloft. This will bring another round and showers or occnl rain late tonight into Thu. Lows tonight drop off into the the low to mid 40s once again. Thursday most of the CWA will see those showers and rain continue into at least the early afternoon, but it should be winding down mid to late afternoon. And once again temps across much of the CWA will be on the cool side, mainly in the mid to upper 50s. However, models suggest that the weak sfc low actually crosses somewhere from around KLEB-KPSM during the afternoon and this could put interior S NH into the warm sector, which means maybe some partly sunny skies and definitely warmer temps with highs in the 65-70 range. It cuts a fine line in the forecast, so confidence is lower on where the sfc low actually ends up, but at least theres some optimism for a part of the CWA Thu. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Overview: A 500 mb ridge and surface high pressure build in for the end of the week which will keep things dry, but an upper low offshore looks to keep temperatures on the cooler side. The ridge moves off to the east Sunday night and after a frontal passage warm temperatures do look to arrive for the beginning of next week. Impacts: * No significant weather impacts expected Details: Light showers linger overnight Thursday as a shortwave clears the area. Skies remain cloudy through the night keeping low temperatures in the 40s south of the mountains and in the upper 30s to the north. Surface high pressure and a 500 mb ridge begin to build in to the region on Friday. This will help temperatures warm a bit, but an upper level low to the east will advect cooler marine air into the area at the same time, capping 850 mb temperatures at 2-3C. Therefore, we likely only see high temperatures top out in the upper 50s across much of the area with low 60s possible in southern New Hampshire and the Connecticut River Valley. With continued clouds low temperatures will be similar to the night before, low 40s in the south and upper 30s across the north. Saturday will be mostly dry as well with the ridge axis overhead. Again, this would normally suggest warming temperatures, but cool North Atlantic marine air will continue to be advected into the region by an upper low close by. High temperatures look to end up very similar if not even a degree or two cooler than Friday. The surface high and 500 mb ridge both begin departing to the east Saturday night which will also move the upper low along as well. Cool northeast flow turns into warm southwest flow during the day Sunday as the ridge continues east. This means that clouds won`t be going anywhere as the column stays moist. A low pressure system passing to our north may drag a front through the region resulting in some rain showers Sundays afternoon and evening. The 500 mb pattern remains unsettled to begin the week with shortwaves continuing to rotate through the area so chances of rain showers will stay in the extended forecast, but with continued southwest and westerly flow, we may finally get the warm up we have been waiting for with ensembles suggesting clearing skies that may help us take full advantage of 850 mb temperatures climbing into the 8-10C range. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... Short Term...Hard to see much, if any VFR through Thu. Given the rain ending and some cooling in the pre-dawn should see a few hours of IFR fog/cigs in most terminals, but this should improve to MVFR during the morning inland and by midday at the coastal terminals. Another weak low moves through late tonight and Thu, and this will being some IFR conds late tonight into Thu morning, before we return to MVFR again. Long Term...VFR is the prevailing condition through Saturday, with the next chance for restrictions being on Sunday as ceilings lower and rain showers cross the area. && .MARINE... Short Term...Expecting a brief surge in SSE flow ahead of cold front on Thu, but should top out with 20 kt gusts for a few hours, and thus, no SCA conds expected. Long Term...Conditions hazardous to small craft are not expected. Winds will largely be less than 10kts with some gusts to 15kts, initially northeasterly Friday and Saturday and then shifting southeasterly for Sunday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ SYNOPSIS... NEAR TERM...Cempa SHORT TERM...Cempa LONG TERM...Baron AVIATION... MARINE...