Area Forecast Discussion
Issued by NWS Caribou, ME

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000 FXUS61 KCAR 172141 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 541 PM EDT Mon Jul 17 2017 .SYNOPSIS... A weak front will remain nearly stationary across northern Maine tonight. A weak cold front will cross the area Thursday and will be followed by a stronger cold front Friday. Weak high pressure will build into the area Saturday. && .NEAR TERM /THROUGH TUESDAY/... 530 PM Update: Latest hrly meso-model output is indicating that some of the high cnvctn from Nrn VT and NH will likely reach NW ptns of the Rgn going into erly eve before diminishing late this eve. Subsequently, we added a couple more hrs of enhanced tstm element wording for the NW and beefed up the 00-06z QPF total ovr this area. Otherwise, we updated fcst hrly temps/dwpts based on the latest late aftn sfc obs, which shows considerable lcl variability due to rn cooled areas across the N. Fcst ovrngt lows were not chgd sig this update. Orgnl Disc: Showers and thunderstorms had a bit of a hard time getting their act together this afternoon, but they are now popping up in earnest as a weak upper shortwave lifts across central New England. These showers/thunderstorms will be mainly scattered through early evening, with the most persistent activity stretching across the Katahdin region and North Woods. Much of the hi-res guidance, including the HRRR, NMM, RAP, and ARW all show the upstream convection across VT holding together and hitting our western areas as a fairly consolidated line sometime in the 6pm to 8pm timeframe. This line should weaken as it moves eastward, but it may still be strong enough to produce gusty winds, small hail, and heavy rainfall in far western portions of our forecast area. Have therefore kept the enhanced wording in for the next several hours. All convection will pretty much dissipate by midnight with some showers persisting over the higher terrain in the North Woods. The concern then becomes yet another night of fog and low stratus. Moisture profiles along the coast look conducive for drizzle, as well. Lows will be in the lower to mid 60s. For Tuesday...the weakening upper trough will finally swing across the region, producing yet another day of afternoon showers and thunderstorms, especially across the north and west. Instability doesn`t look nearly as good as what we`ve seen over the past couple of days, so don`t anticipate any strong storms. However, with plenty of moisture to work with, locally heavy rainfall will be a threat. Highs will be in the mid 70s to around 80 in most spots, with the coast in the mid 60s to lower 70s. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... A mid level trough axis along the Maine/NB border late Tue afternoon moves east into NB Tue evening and is briefly followed by a weak ridge. Any thunderstorms Tue evening should end with the loss of daytime heating. The threat of showers will diminish too, but with a mild and muggy air mass an isolated shower can`t be ruled out through late evening. There will likely be some areas of fog, especially over the coastal waters and along the Downeast coast. On Wednesday, a weak surface trough moving into Maine will provide the focus for isolated to scattered showers and storms, mainly during the afternoon and evening. As a weak trough moves to the Downeast coast Wed night and there could be just enough convergence and moisture around for an isolated shower. Once again there will likely be areas of fog around, most widespread along the coast. Very brief surface ridging is expected for Thu morning ahead of an approaching cold front that will be organizing to the west across Quebec during the afternoon. As the front draws closer to the region in the afternoon the chance of showers and storms will be on the increase, especially across northern and western portions of the CWA. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A cold front is expected to cross the area later Thu night into Fri with showers and thunderstorms. The timing of the frontal passage and cloud cover will be important factors as to whether any of the storms can become strong or severe. The front pushes off the coast Fri evening and is followed by drier/cooler air Saturday. The next system across the Great Lakes begins to approach Sun with the chance of an afternoon shower or thunderstorm, mainly across the northwest half of the CWA, but it is possible that any activity could hold off all day as there remain timing differences between the models and model ensembles. The system coming in from the Great Lakes will likely produce some showers and the chance of thunderstorms Sun night and Monday along with a more humid air mass. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... NEAR TERM: VFR conditions will prevail through 03z Tuesday. Scattered showers and thunderstorms are possible at CAR/PQI/FVE through 03z Tuesday, and these may produce local MVFR or IFR. Thereafter, expect all sites to see ceilings below 1000 ft and visibility of 2sm or less in fog and low stratus, starting at BHB at 03z and reaching FVE at 08z Tue. These conditions will persist until 13z, then all sites will improve to VFR with scattered afternoon showers. SHORT TERM: Conditions will be variable. Mainly VFR at the northern terminals, but briefly lower conditions are expected in any fog at night/early morning and in showers and t-storms. At KBHB there will be times of VLIFR in low cloud/fog, especially at night and early morning, with mainly VFR from the mid morning hours into the early evening. AT KBGR, mainly VFR during the day and evening, but with IFR possible in low cloud/fog late night and early morning. VFR expected at all the terminals Sat. && .MARINE... NEAR TERM: No headlines will be needed over the waters through Tuesday. The main concern will be areas of dense fog which will reduce visibility to 1SM or less at times. SHORT TERM: The wind and seas will remain below small craft advisory levels through the end of the week. The biggest concern will be for areas of locally dense fog at times until the cold front pushes through later in the day Friday. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...VJN Short Term...CB Long Term...CB Aviation...VJN/CB Marine...VJN/CB

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