Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
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561 FXUS61 KCAR 090205 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 1005 PM EDT Sat Jun 8 2024 .SYNOPSIS... Low pressure over east central Quebec tonight slowly tracks east into the Canadian Maritimes Sunday, as a coastal low passes to the south. The low over the Canadian Maritimes continues to slowly move east Monday through Tuesday, bringing weak troughs of low pressure through the region as it does so. Weak high pressure then builds in Tuesday night and Wednesday, then slowly slides to the east through Thursday, allowing a warm front to lift to the north. && .NEAR TERM /THROUGH SUNDAY/... 10:05PM Update...Minor tweaks to the forecast with scattered showers across the area. Adjusted the Temp/Dew trends over the next couple hours. Previous Discussion... A broad area of low pressure over northern New England will continue to slowly churn northeastward this evening into the night tonight. Isolated to scattered thunderstorms of the early evening are primarily driven by diurnal heating, and as such, will begin to taper off as the sun sets tonight. With the center of the low passing just north of the St. John Valley, scattered rain showers remain possible across the north through the night tonight, while the Downeast region may begin to clear out. That said, the rain from earlier has increased low level moisture, increasing the chance for areas of dense fog to develop, potentially reducing visibility. For the day on Sunday, the broad area of low pressure will continue to influence the synoptic weather pattern, and diurnal heating will once again provide enough lift to take advantage of the instability and moisture across the region for another day of scattered showers and storms. Forecast soundings indicate slightly smaller CAPE profiles than was seen with the Saturday storms, though the HREF does suggest up to 500 J/kg MUCAPE is possible Sunday afternoon, limiting severe potential. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... The cutoff low tracks across northern Maine into New Brunswick Sunday night. Should see showers with possibly some rumble of thunder across the North in the evening, ahead of the low, taper off as the circulation moves to the east. Other than possibly a few strong storms with locally heavy rainfall early in the evening over Eastern Aroostook, any precipitation which falls Sunday night should not have any significant impact. Lows Sunday night should be near normal. The region remains in the residual trough from the departing and weakening cutoff low Monday-Tuesday. The result will be mainly diurnal showers with decreasing coverage and intensity from Monday into Tuesday. Limited pops to chance on Monday and slight chance on Tuesday and used areal coverage wording to reflect this. While a rumble of thunder cannot be completely ruled out MOnday and Tuesday, the chance of occurrence is too low to reflect in the forecast at this time. Expect any diurnal showers to become increasingly more of a miss than hit nature during this time. Highs Monday and Monday night should be near normal and highs on Tuesday should be around 5 degrees above normal. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... The region will continue to see diurnal convection Tuesday night-Wednesday night as the residual troughing slowly dissipates over the region. A northern stream shortwave passes on Thursday bringing with it a chance of showers and a slight chance of thunder, with the best chance across the North - which is closest to the best dynamics with this system. There could be some lingering showers Thursday evening depending on exactly how fast the northern stream shortwave exits, otherwise it should be dry Thursday night in the wake of this system. The models then differ in the handling of the next northern stream system, with the ECMWF and CMC fairly well clustered along with most ensemble members, with a slower system than the more progressive GFS. Given the overall tendency of the GFS to be too progressive as a whole, favored a CMC/ECMWF blend Friday- Saturday. As a result have highest pops late Friday/Friday night along with a slight chance of thunder, when the associated cold front is most likely too pass. There could be some residual showers on Saturday with the arrival of the upper level cold pool. It is too early to assess the severe potential with this system, but if it ends up being a night time frontal passage, that tends to suggest that severe weather is less likely due to a lack of solar heating. Temperatures are forecast to be near normal Tuesday night, then above normal Wednesday-Saturday. The temperature forecast is of below normal confidence Friday-Saturday given the uncertainty in the timing of the system then. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... NEAR TERM: Showers and thunderstorms continue across all terminals early this evening. Any moderate to heavy rain showers could briefly bring vis and cigs down to LIFR. Otherwise, SCT to BKN IFR to low end MVFR cigs continue across Downeast terminals, while BKN IFR cigs continue for the most part across northern terminals. Winds light and variable. Overnight, Downeast terminals likely to improve towards VFR, though patchy fog could bring the threat for IFR conditions at coastal terminals/BHB. From HUL north, cigs will likely remain IFR with lingering SHRA, though the lightning threat will diminish overnight. Winds SW around 5 to 10 kts. On Sunday, ceilings may briefly improve towards VFR through the morning, but another round of showers ant thunderstorms will lead to deteriorating conditions falling to low end MVFR to IFR. A return of lightning is possible to all non-coastal terminals Sunday afternoon. Winds SW around 5 to 10 kts. SHORT TERM: Sunday Night/Monday morning...MVFR or lower possible. Monday afternoon-Wednesday...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. Wednesday night...VFR. Thursday...VFR, except for brief period of MVFR possible in any stronger convection. SW winds G15-20KT possible. && .MARINE... NEAR TERM: Winds and seas should remain below small craft advisory levels through tonight and Sunday, though a few brief gusts to 25 kts are possible in any rain showers early this evening and again late Sunday afternoon. Patchy fog overnight tonight could reduce visibility below 1 SM. SHORT TERM: A light to moderate pressure gradient over the waters Sunday night and Monday should allow for winds up to 15 kt along with some gusts to around 20 kt. Seas up to 4 ft are possible. The pressure gradient relaxes and should be light Monday night- Thursday, limiting winds to 10 kt or less over the waters. Seas should be 3 ft or less until possibly Thursday when a building S-SW swell could increase seas to up to 3-4 ft on the waters. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...AStrauser/Sinko Short Term...Maloit Long Term...Maloit Aviation...AStrauser/Sinko/Maloit Marine...AStrauser/Sinko/Maloit