Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 241137 AAA AFDGYX Area Forecast Discussion...UPDATED National Weather Service Gray ME 637 AM EST Thu Jan 24 2019 .SYNOPSIS... Low pressure will drag a trailing cold front across the area today as it passes by to our north and west. Weak low pressure will approach from the west Friday, before crossing the region Friday night. A weak ridge of high pressure will pass over the region Saturday. Low pressure will track through southeastern Canada Sunday, before a cold front sweeps across the region Monday. High pressure will follow on Tuesday. Yet another area of low pressure will pass by to our north and west Tuesday night into early Wednesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 630 AM Update... Have adjusted temperatures slightly for this update. Portions of southern NH are warming quickly, with Jaffrey at 49 degrees this hour. Just a few miles north, temperatures are in the upper 30s, so there is a large temperature discrepancy as warm air moves north. Freezing rain is still occurring in the winter wx advisory area where temperatures are in the 30s. Although some sites like Laconia, Fryeburg, and Lewiston are above freezing by a few degrees, local data plots show many other readings in the lower 30s. So have not cancelled any advisories and will likely let them go until they expire at 8 AM. Temperatures will need a lot of adjusting today as this event unfolds. Previous discussion... Synoptic scale flow is currently dominated by a highly meridional ridge over the west coast, with a deep trough covering most of the central CONUS. The East Coast also has a ridge along the length of it. The coldest center of the trough was located well to the north near Hudson Bay, where temperatures are in the -30 to -40F range. A piece of the polar low will dip down into the northern Plains today and push a downstream short wave across our forecast area. At the surface, a warm front was located in southern Canada with a surface low progged to deepen as it moves east from the Great Lakes. Precipitation associated with broad warm advection was spreading across northern New England this morning with a mix of precipitation types as the warmer air advanced northward. In general, the winter wx advisories across southern NH and southern Maine were allowed to expire with p-type having changed to light rain. Elsewhere to the north advisories remain in place mainly for freezing rain which will last longest over northern Coos, N. Oxford, N. Franklin, and central Somerset Counties. Even as the winter weather threat begins to come to an end there are still a couple more hazards we have to deal with, including moderate to heavy rain and strong winds. Concerning the rain, CAMs are showing several slugs of rainfall moving through today, some of which will be concentrated on a trailing cold front moving through later this afternoon. PW values are around 225% to 250% of normal, and this combined with poor drainage due to snow and ice has prompted a flood watch for southern NH and SW Maine (basically where their is not as much snowpack to absorb the rain). Ensemble river forecasts are also pointing towards several rivers reaching minor flood stage. In tandem with low pressure moving across the forecast area today, a strong LLJ approaches from the south and pivots over the region, peaking around 100 kts offshore. A wind advisory remains in place for the coast for today and tonight with gusts to 40-50 mph possible. Temperatures warm into the 40s to near 50 today, which will help mix winds aloft down to the surface. In addition, the strong winds are not very far off the ground, less than a 1k ft in some cases, and the heavier rain expected will also help bring the winds down to the surface. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... Clouds and showers linger for the mountains overnight with lows in the teens north to 20s south. Cooler tomorrow with highs in the mid 20s to mid 30s with clearing skies downwind. A trough crosses the forecast area bringing light snow showers to the mountains and the CT River Valley. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Ensemble and deterministic model solutions remain in good agreement on the long wave pattern through the upcoming weekend and well into next week. The current high amplitude pattern across the CONUS will remain locked in place featuring the west coast ridge and a deep trough across the remainder of the lower 48. The real question this forecast period is when and to what degree phasing occurs between northern and southern stream energy. Otherwise...we`re left with a dominant northern stream and below normal temperatures with repeated outbreaks of arctic air across the region punctuated by brief warm ups ahead of several disturbances. At present...models are suggesting the potential for a significant winter system Tuesday into Wednesday next week. However some uncertainty remains as energy responsible for this system is still well out over the data sparse Pacific Ocean at moment. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... Short Term...Conditions are ranging from IFR to MVFR this morning in FZRA and RA. HIE should be the last to change over to plain rain and this should occur later this morning. Winds will increase out of the south tomorrow with gusty winds along the coast reaching 30kts. Aloft a very strong LLJ will result in LLWS at all sites through the day. Rain comes to an end towards 00Z today. Long Term... Sat...Sct MVFR in mtn -shra. Sun...Areas of MVFR in -sn. && .MARINE... Short Term...Increasing southerly flow will reach storm force on the eastern waters as a very strong low level jet moves through the region. In the bays and further west have left gales as the core of the jet will pass to the east...however a few gusts to storm force are possible. Long Term... Sat - Mon...SCA`s psb outside the bays. && .TIDES/COASTAL FLOODING... High astronomical tides will continue today. High water levels will combine with building seas to produce beach erosion and splash-over near the time of the early afternoon high tide. A coastal flood statement has been issued for early this afternoon. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Winter Weather Advisory until 8 AM EST this morning for MEZ012>014. Flood Watch through this evening for MEZ018-019-023-024. Wind Advisory until 9 PM EST this evening for MEZ023>028. Winter Weather Advisory until 11 AM EST this morning for MEZ007>009. NH...Winter Weather Advisory until 8 AM EST this morning for NHZ001>006. Flood Watch through this evening for NHZ007>015. Wind Advisory until 9 PM EST this evening for NHZ014. MARINE...Gale Warning until 9 PM EST this evening for ANZ151-153-154. Storm Warning until 9 PM EST this evening for ANZ150-152. && $$ NEAR TERM...Hanes SHORT TERM...Hanes LONG TERM...Schwibs

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