Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
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507 FXUS61 KCAR 060110 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 910 PM EDT Fri Jul 5 2024 .SYNOPSIS... A stationary front will remained stalled across the area overnight and slowly lift back north Saturday in the form of a warm front. A weak cold front will begin to cross the region Sunday and move east of the region Monday. Low pressure approaches from the west Tuesday night and Wednesday. && .NEAR TERM /THROUGH SATURDAY/... 9:10 PM Update: Area radars showing showers across mainly southern Piscatquis County and into central Penobscot County. Have made fairly significant changes to the PoP grids for late this evening to lower the Pops significantly Downeast and also north of Millinocket. Looking at a broader picture, there are showers and storms in southern New England as well as well as to the west of the Saint Lawrence River Valley. Expect that after midnight that shower chances will be on the increase, especially Downeast and also across northern areas. Low clouds and the marine layer have pushed north of Bangor and will continue to lift north overnight. Fog is developing along and near the coast, but whether it becomes dense remains more uncertain. It is possible that as shower coverage likely increases late tonight that it may cause some improvement to the visibility. Previous discussion: The warm front will continue to move northward through the region tonight. Thunderstorm activity will decrease by sunset with the lose of daytime heating and lift with the front. In addition, S flow will help stabilize the area. After midnight, high-res models show the front stalling over the North Woods and central Aroostook with light rain showers continuing over this area. The main concern tonight will be the areas of fog with the onshore flow, moist atmosphere, steep inversion, and warmer temps. Downeast could see some dense fog tonight and early Saturday morning. By Saturday, the low pressure system over the Great Lakes will move along the upper level trof through the morning. Rain showers will continue with the progression of the system. Models are in better agreement with the heavier rainfall staying to the north in the afternoon as the center of the low pressure system moves over the state. Upper air model soundings indicate instability in the north as well, which will increase the chances of localized heavy rain with isolated thunderstorms. However, CAMS have decreasing confidence in the heaviest rain in the north, so left out enhanced wording in the forecast. Cooler temps on Saturday with the warm front sinking south and S flow decreasing. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... Expect showers and thunderstorms to gradually exit the area by later in the night. Any thunderstorm activity will likely be elevated as a veneer of low clouds and fog will likely cover the area Saturday night into Sunday morning. High PWs and deep moisture means some showers/thunderstorms could produce locally higher amounts of rainfall, but models have little consensus on precip amounts or placement for Saturday night. Weak surface low moves across the Crown of Maine during the night and will drag a very weak cold front across the area into Sunday. Have maintained chance PoPs for showers and a slight chance of afternoon thunderstorms, but expect a cap will limit instability and development of any stronger showers. The large subtropical high off the Eastern Seaboard builds into the area Sunday and Monday with increasing stability and continued heat/humidity. Highs on Sunday will be in the low to mid 80s with heat indices up to around 90F but falling short of Heat Advisory criteria. Temperatures increase Monday into the mid to upper 80s. Once again, expect heat indices to fall shy of advisory criteria, but it will certainly be uncomfortable by northern/eastern Maine standards. Nighttime temperatures will offer little relief with lows in the mid 60s for much of the forecast area. The humid air will promote another night with areas of fog for Sunday night. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Another warm and muggy night is forecast for Monday night. Tuesday may be the warmest day of the week with highs in the upper 80s to around 90F. A weak cold front sags southward towards the area Tuesday afternoon and will likely spark thunderstorm activity. An upper trough swinging southeastward out of the Great Lakes region moves into the region Tuesday night into early Wednesday. Enhanced lift along the frontal boundary could generate heavier showers and thunderstorms Tuesday night into Wednesday. Deeper tropical moisture from the remnants of Beryl may be pulled northward along the boundary during the period. The upper trough and frontal boundary shift southward enough by Wednesday night into Friday to bring drier weather and nominally cooler temperatures/humidity. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... NEAR TERM: Aroostook terminals...VFR late this evening, then decreasing to IFR/LIFR after midnight in low cigs and patchy fog. Light and variable winds. For Saturday, IFR/LIFR in the morning, then MVFR by the afternoon due to rain showers. SSE winds around 5 kts. BGR and BHB...IFR in low cigs/vsby. Light and variable winds. For Saturday, IFR/LIFR conditions all day in showers and low cigs. SSE winds around 5 kts. SHORT TERM: Saturday night...IFR to LIFR in fog and low clouds. Embedded thunderstorms are possible. Sunday...Low clouds and fog will burn off and all sites will be VFR by afternoon. There is a slight chance of a thunderstorm in the afternoon, but chances are trending down. Sunday night...Another night of IFR to LIFR in fog/low clouds. Monday...Early morning fog burns off, giving way to VFR conditions by mid-morning. Monday night...Fog is most likely for BHB, most likely VFR inland. Tuesday...Generally VFR with a chance of afternoon thunderstorms. Tuesday night and Wednesday...Becoming IFR due to low clouds. Chance of thunderstorms. && .MARINE... NEAR TERM: Winds and seas remain below SCA conditions tonight and Saturday. Reduced visibilities in areas of fog. SHORT TERM: Thunderstorms are possible Saturday night and again Tuesday night into Wednesday. Fog will be prevalent throughout the period in the very humid air mass. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...CB/LaFlash Short Term...MCW Long Term...MCW Aviation...CB/LaFlash/MCW Marine...CB/LaFlash/MCW