Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
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260 FXUS61 KCAR 100412 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 1212 AM EDT Mon Jun 10 2024 .SYNOPSIS... A low will slowly track northeast through the Maritimes through Wednesday night, bringing a series of weak troughs of low pressure across the region as it does so. A warm front slowly lifts to the north Thursday and Thursday night. A cold front approaches from the west on Friday. && .NEAR TERM /THROUGH TODAY/... 12:10 AM Update...Forecast remains on track as an area of rain persists across the far north with just isolated showers elsewhere. Lowered temps a couple degrees over the north. Otherwise, forecast remains on track this hour. Previous Discussion: Wrap around moisture behind the back side of the low will persist the threat for rain for the north through the night. With persistent overcast skies and lingering low level moisture, low temperatures will only fall into the low to mid 50s. For the day on Monday, numerous to widespread rain showers across the north will begin to taper off as the low continues to exit further to the east. However, PWATs remain around 1 inch due to the moisture advection of the weekend, and with diurnal heating, will result in afternoon convective showers. A few thunderstorms are possible for Monday afternoon, but CAPE will be limited with more stable air working in ahead of the next ridge of high pressure, so thunderstorm threat is limited. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY/... A full latitude trough continues to build into the region Monday night. A closed upper low develops over the region Tuesday, then slowly lifts northeast across Maine as it gradually opens again though Wednesday. The result will be mainly diurnally driven convection through this time frame. The cold pool with the upper low continues to modify through the period, so expect any showers to be more widespread on Tuesday than on Wednesday. With that said, the forcing is not impressive, so do not expect more than scattered coverage on Tuesday, mainly across the North, and then only isolated coverage on Wednesday just across the North. Noting the warming cold pool aloft and limited dynamics, while a rumble of thunder cannot be completely ruled out, there is not sufficient confidence in its occurrence to place it in the forecast at this time. Lows Monday night should be near normal, with highs on Tuesday around 5 degrees above normal. Lows Tuesday night should be a few degrees above normal and highs on Wednesday should be a degree or two warmer than those on Tuesday. With plenty of low level moisture, along with some clearing overnight and light winds, cannot rule out some patchy fog late at night/early each morning as well. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... The northern stream portion of the upper trough exits to the northeast Wednesday night, allowing for weak northern stream shortwave ridging to build in overnight. It should be dry as a result. A northern stream shortwave passes Thursday bringing with it a chance of showers and a slight chance of thunder. At this time it appears that any storms should be at most strong. The models have come in better agreement with the timing of the next more significant system, but still differ on the details. Given the continued model uncertainty, beyond that which is typical for the extended time frame, have opted to limit pops to at most chance Thursday night-Saturday. A northern stream shortwave passes to the north Thursday night, bringing some isolated to scattered showers - once again mainly across the north. The main axis of a northern stream trough approaches Friday, then crosses the area Friday night. This should bring some scattered showers along with a risk for some thunderstorms. This will be the most organized convection of the week, with decent CAPE and shear expected - there is the potential for strong to possibly severe storms Friday afternoon/evening ahead of the surface cold front. There is still a bit of uncertainty on the timing of the system, so a mainly if not entirely night time frontal passage cannot be ruled out. If this occurs, then the severe threat would be greatly reduced, if not eliminated. Another northern stream trough passes Saturday, with some scattered showers. The trough could linger into Saturday evening, so do have some pops then, otherwise expect deep layered ridging to build in through Sunday with dry weather. Temperatures should be above normal Wednesday night through Friday night, then near normal Saturday and Saturday night. For now it appears temperatures on Sunday should be a few degrees above normal. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... NEAR TERM: VFR for southern terminals overnight. Patchy fog could briefly lower vis to MVFR/IFR near the coast, but the chance is low (10%). For northern terminals, ceilings will lower from VFR late this evening to MVFR/IFR late tonight with continued rain and rain showers. Winds will remain out of the W to SW and less than 5 kts. Rain will gradually taper off at northern terminals on Monday, but ceilings will be slow to recover. Meanwhile, VFR likely to hang on at southern terminals. Winds W 5 to 10 kts through Monday afternoon. SHORT TERM: Monday night-Thursday...VFR, except for brief period of MVFR possible in any stronger showers in the afternoon and MVFR or lower possible in patchy fog late at night/early in the morning. SW winds G15-20KT possible Monday evening and again during the day on Thursday. Thursday night...VFR. Friday...VFR..except MVFR or lower possible in any stronger shower/thunderstorm. SW winds G15-20KT possible, with LLWS possible at southern terminals. && .MARINE... NEAR TERM: Winds will remain below SCA and seas around 4 ft offshore and 3 ft intracoastal through Monday. A few gusts to 20 kts possible in any rain showers. Moist air over the waters may result in reduced visibility in patchy fog overnight tonight. SHORT TERM: A light to moderate pressure gradient over the waters Monday evening will allow winds up to 15 kt and gusts up to 20 kt, along with seas up to 4 ft. The pressure gradient relaxes late Monday night, becoming light by Tuesday. This light pressure gradient continues through Thursday night, with winds 10 kt or less and seas 3 ft or less. The pressure gradient tightens again on Friday, with winds up to 15 kt. Continued S-SW swells could end up building seas to SCA levels by late in the day on Friday on the coastal ocean waters. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...AStrauser/MStrauser Short Term...Maloit Long Term...Maloit Aviation...AStrauser/MStrauser/Maloit Marine...AStrauser/MStrauser/Maloit