Area Forecast Discussion
Issued by NWS Caribou, ME

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000 FXUS61 KCAR 201611 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 1111 AM EST Tue Feb 20 2018 .SYNOPSIS... A strong ridge of high pressure will remain anchored off the Southeast U.S. coast through Friday. A cold front will drop south into northern Maine today, and will become nearly stationary across southern Maine this evening. The front will lift back north as a warm front tonight. A cold front will cross the area Wednesday, and high pressure will build toward the region from the west at the end of the week. && .NEAR TERM /THROUGH TONIGHT/... 11:10 AM Update...Raised temps a bit across the north where temps are above freezing in most areas. Still expected some cooler air to seep in from the north so winter weather advisories remain in place. Also raised pops over the west central highlands where an area of rain is moving in. Previous discussion... A record strong ridge for February will remain anchored off the Southeast U.S. coast with 500 mb heights around 596 dam, which surpasses the NCEP/NCAR reanalysis for February of 594 dam off the coast of Florida on February 15, 1989. At the surface, a cold front with shallow arctic air will slip into far northwest Maine around daybreak this morning with cold air damming to set up in the Saint Lawrence River Valley. The low level cold air will spill south during the day, but ahead of the area of cold air damming there might be a little surge of slightly warmer air at 925H into northeast Maine for a time. By tonight, the cold air damming shifts east into New Brunswick. Moisture will stream east across the frontal boundary during the next 24 hours, and the big challenge will be the precipitation type across the northern half of the CWA. The good news, the QPF looks to be light. The bad news, some of the precipitation will fall in the form of freezing rain, especially across far northern Maine in the Saint John Valley. Any snow and sleet accumulation will be an inch or less, but a tenth of an inch of ice is possible. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... Big question on Wednesday is how warm will it get? Extremely anomalous airmass with all guidance showing all time high heights and temps from 925mb up. NAEFS Standardized Anomaly is showing 3 to 4 standard deviation 500mb ridge off to the south. The warm front will push through early on Wednesday morning, with southwest flow developing. 925mb temps will surge to close to +17C on the coast and +10C up in the north. If these temps are realized record highs will be easy to reach. Set-up looks good with strong westerly winds at 925mb which is our favorable direction. Could be pushing upper 50s to near 60 in the Bangor region and Interior Downeast. Temps will be a bit cooler along the coast and across the north, but will still be near record territory. Reality quickly strikes back Wednesday night as a surface cold front comes rushing back through, which will quickly drops temps back to near normal during the day on Thursday with NW winds and mostly clear skies. Overall it will still be a nice day, except for all the snow melt puddles refreezing causing slippery side roads and driveways. Shouldn`t be an issue for Downeast and Bangor region as most of the snow will be gone after the melt out. Friday will be another nice day overall with surface high pressure retreating to the east. High clouds will be on the increase as the next weather maker begins to approach the area. Southerly return flow will keep temps moderated with highs remaining in the 30s for Downeast and upper 20s across the north. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... Long term pattern will be active with two potential weather makers as flow stays progressive for a few more days. A quick hitting system is expected Friday night into early Saturday, but looking to be a light QPF event, with .10 to .25" for most areas. Looking like it could be a rain event on the coast, could be a light corridor of mix precipitation across Central Maine, and snow for the north. Will work out details once we get closer. Quick cool down for Saturday with high pressure returning which will bring good weather for the majority of the weekend. Both the GFS and ECMWF camps are hinting at another system Sunday night into Monday. This one could be a little bigger as a coastal low could develop, but still not looking like a significant event. Storm looks like it will be mostly on the frozen side at this point, except for the immediate coast. Could also have some winds and waves for the coast with a prolonged southeast wind. && .AVIATION /16Z TUESDAY THROUGH SATURDAY/... NEAR TERM: Predominately IFR into tonight with LIFR at times. Light rain, drizzle, and fog at the Downeast terminals. Mixed precipitation expected from KHUL north to KFVE with some icing expected, especially so at KFVE. SHORT TERM: Chance for some coastal fog at KBHB during the day on Wednesday that could bring IFR conditions. The remainder of the TAF terminals will be VFR, with breezy southwest winds. Cold front pushes through on Wednesday night. High pressure expected on Thursday and Friday with not impacts to aviation operations expected. && .MARINE... NEAR TERM: Have dropped the small craft advisory for the intra- coastal waters, but with seas still 7 to 8 feet at Jonesport have extended the small craft advisory on the coastal waters until noon. Conditions are expected to be below sca levels this afternoon into tonight, although the southwest flow will pick up again tonight and another small craft advisory may be needed late tonight. SHORT TERM: Strong SW flow over the waters expected on Wednesday, but could be a shallow stable layer, which will limit the potential strength of the winds. SCA conditions will be possible during the day on Wednesday, seas will remain around 4 to 6 feet. Surface cold front will push across the Gulf of Maine Wednesday night with NW winds over the waters. High pressure is expected over the coastal waters Thursday and Friday, with a southerly return flow developing Friday afternoon. && .HYDROLOGY... Will be watching the rivers closely on Wednesday night into Thursday for some possible ice movement. Decided not do issue any flood watch headlines, due to a few reasons. First, QPF still looks light for this event with generally .50" or less expected. Second, is the longevity of the thaw expected. Even though temps are above freezing for parts of the Penobscot river watershed today, they won`t be that warm with most areas staying in the mid 30s. The real warmth will come on Wednesday and we are expecting rapid snowmelt with dewpoints surging to 50 degrees and temps will also reach into the upper 50s for the lower Penobscot watershed and low 50s for the upper part of the watershed. Fortunately the cold front will quickly push through Wednesday evening and night, dropping temps quickly back below freezing. The longevity of the warm spell will be too quick for areas that still hold a significant snowpack. We do expect river rises due to run-off, but current forecasts are only showing a few feet of a rise, not enough to really break up the ice. There will be weakening of the ice pack though, especially on the edges, so some ice will be moving around, but no significant ice jams are expected. Overall threat is there, but current thinking is the threat is low. Users with interests on area rivers across the lower Penobscot watershed should keep a river watch though on Wednesday and Wednesday night. && .CLIMATE... The projected record strong 500H ridge off the southeast U.S. coast will send a very warm air mass into northern and eastern Maine Wednesday. The all-time record high for February at Bangor is 60F, which was established on February 21, 1937. We are currently forecasting a high of 60F, so the all-time record high is in jeopardy. Here are some other high temperature records that are in jeopardy for for 2/21 along with the forecast high in parenthesis: Houlton: 50F, 1953 (53F) Caribou: 48F, 1994 (50F) && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Winter Weather Advisory until 4 AM EST Wednesday for MEZ001- 002. MARINE...None. && $$ Near Term...CB Short Term...Dumont Long Term...Dumont Aviation...CB/Dumont Marine...CB/Dumont Hydrology... Climate... is the U.S. government's official web portal to all federal, state and local government web resources and services.