


Area Forecast Discussion
Issued by NWS Portland, ME
Issued by NWS Portland, ME
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125 FXUS61 KGYX 031442 AFDGYX Area Forecast Discussion National Weather Service Gray ME 1042 AM EDT Thu Apr 3 2025 .SYNOPSIS... A warm front is lifting through northern New England this morning. While much of the area will be rain, a period of snow changing to a wintry mix is expected across interior western Maine and parts of the White Mountains. Fair weather returns for Friday as a high pressure builds into the region. Yet another chance of a wintry mix arrives this weekend as a storm heads through the St. Lawrence River Valley. The pattern will remain unsettled into early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 1030AM...Quick update to take down the Winter Weather Advisory, as most locations are now reporting plain rain and above freezing temperatures. 930AM...Forecast remains on track. Radar, satellite and observations show temperatures just a hair above freezing across most of New Hampshire and Maine with some below freezing temperatures still hanging on in Franklin and Somerset county. A strong cold front arriving into the region has allowed for the development of convective showers across the south. Thunder has been reported across the region, and most wintry precipitation has been transitioned to rain. Opted to significantly lower ice totals outside of higher elevations to reflect where temperatures are at the moment, with no other changes needed at this time. The aforementioned cold front is starting to weaken substantially as it nears the east coast. Chances for thunder will decrease through the morning as convective storms start to disorganize, forming into a stratiform rain shield. This is a quick moving front, with most rain exiting the region by this afternoon. Skies will start to clear out tonight, though a mostly overcast afternoon is still expected. 615AM...RAP mesoanalysis is pretty bearish on instability but thunderstorms continue on both the warm front and in a decaying line ahead of the cold front. I have expanded the coverage of isolated storms in the forecast this morning and adjusted the mixed precip based on latest observational trends in surface temps. 410AM...No major changes to the forecast with this update. Temps are fairly consistent across the forecast area...but moisture is a little more variable from southwest to northeast. From a HIE to RKD line and points north...low level RH values remain around 60 percent. That leaves some room for wetbulb cooling down below freezing. These areas will be most likely to see a period of snow then wintry mix this morning. I have left winter weather advisories in place...but may be able to start trimming these if temps do not budge from current readings. The second round of precip is now pushing into the local area at this hour. While the band of precip is relatively narrow...it is quite focused along the mid level warm front. Within the warm sector lapse rates are quite steep...and there is quite a bit of convection along both the warm and cold fronts. I have added isolated thunder to the forecast area southern NH...where the warm front will linger the longest. I have opted for the cooler of guidance today...as cold air dams are often more stubborn than modeling would have you believe. Moist advection thru the day may also leads to blossoming areas of fog later today and into the evening. I have added this to the forecast starting mid afternoon as well. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Cold front will cross the region tonight and low level moisture will be swept eastward with it. Clouds will scatter out south of the mtns...while some upslope cloud cover lingers in the mtns and perhaps a few showers. Temps should be a steady step down in CAA...so I leaned away from MOS guidance. Fri will be warmer and breezy for an otherwise decent spring day. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... 04Z Long Term Update... Latest guidance continues to be in good agreement for a period of precipitation from a wave of low pressure to impact the area Saturday afternoon through part of Sunday. Temperature profiles look to support a period of mixed wintry precipitation initially across the foothills and points north with primarily rain likely further to the south and east. Did continue to incorporate this mixed precipitation in the weather grids. After this system mainly dry and cool temperatures look to prevail. Previously... Overview: High pressure will build in Friday for fair weather. A period of active weather follows as wave of low pressure track along a frontal zone that slowly shifts south of the area early next week. The first wave will bring widespread wintry precipitation late Saturday into Sunday. Thermal profiles with this system will support snow/wintry mix across the interior early Saturday night with a transition to rain from SW to NE Sunday morning. There may be a lull in precipitation Sunday afternoon before the next wave of low pressure tracks across southern New England Sunday night. Chances for precipitation drop off Monday while global models suggest additional systems will be possible towards the middle of next week with a trough approaching the Northeast. Impacts: Snow to a wintry mix could bring slick travel across northern areas late Saturday through Saturday night. Details: Drier air will work into the area Thursday night into Friday on NW flow. A NW gradient will remain over area Friday as high pressure builds in from west with wind gusts approaching 25 mph. Skies will turn mostly sunny by Friday afternoon with highs ranging from the mid 40s north to mid 60s across southern NH. High pressure will crest over the area Friday night allowing for lows to drop into the low 20s to low 30s from north to south. A wave of low pressure will track from the Ohio Valley towards the St Lawrence Valley late Saturday into Sunday with precipitation likely overspreading the area by Saturday afternoon. A dry airmass in place will allow for some wet bulbing leading precipitation starting as snow across the north and a mix of rain and snow south of the mountains. Warm air advection will continue through Saturday night with precipitation changing to a wintry mix across the north and rain across the south by Sunday morning. Temperatures will eventually rise above freezing across all areas after day break Sunday with rain becoming the dominant precipitation type. Precipitation will taper off Sunday afternoon before the next wave of low pressure approaches Sunday night. The next wave of low pressure will bring chances for rain south of the mountains and a mix of rain and snow across the north Sunday night into Monday. Colder air attempts to work into the region Monday night that may allow for snow showers south of the mountains. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... Short Term...Widespread MVFR CIGs will continue to gradually lower thru sunrise. Precip is also moving into the area again from the southwest. Temps continue to creep upwards and so largely rain is expected at TAF sites in NH. Also cannot rule out a rumble of thunder across southern NH terminals. HIE may have a brief period of snow or a wintry mix before changing to rain. Across ME AUG and RKD may start as snow before mixing and eventually changing to rain this morning as well. Widespread IFR or lower conditions are expected thru today and into the overnight when a cold front will then mix out the cloud cover and VFR conditions return to the area. Long Term...Lingering MVFR cigs Thursday night will transition to VFR Friday into Saturday morning. Waves of low pressure brings a brief period of a wintry mix late Saturday changing to rain Saturday night with rain continuing through Sunday. Periods of IFR to LIFR will be possible late Saturday through Sunday. Some improvement is possible Sunday afternoon before the next system crosses New England Sunday night into Monday. && .MARINE... Short Term...South southwesterly LLJ will move across the waters this morning with gusty winds and building seas. SCA remains in effect for all waters. Areas of fog are possible tonight before the cold front crosses the waters. It will remain breezy behind the front thru Fri which will delay seas diminishing below 5 ft outside of the bays until Fri afternoon. Long Term...Winds shift out of the west Thursday night with gusts to 25 kts until Friday morning. High pressure builds over the waters Friday with winds and seas likely dropping below SCA thresholds by Friday afternoon. Waves of low pressure will track across New England this weekend with winds and seas approaching SCA thresholds Saturday night into Sunday. Winds will drop below 25 kts Sunday night while seas remain elevated into Monday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ150>152-154. Small Craft Advisory until noon EDT today for ANZ153. && $$ NEAR TERM...Legro/Palmer SHORT TERM...Legro LONG TERM...Schroeter/Tubbs AVIATION...Legro MARINE...Legro