Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
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243 FXUS61 KCAR 051143 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 743 AM EDT Fri Jul 5 2024 .SYNOPSIS... A weak cold front will stall across the area today. The front then slowly lifts back north Saturday in the form of a warm front. Another weak cold front will begin to cross the region Sunday and move east of the region Monday. A surface trough is expected to cross the area Tuesday. && .NEAR TERM /THROUGH TONIGHT/... Update... Have issued a Dense Fog Advisory for the Downeast coast through 9 AM with this update. Otherwise, have updated to adjust for current conditions. Previous Discussion... A weak cold front will stall across northern Maine today into tonight. Aloft, an upper level disturbance will cross the region today into tonight. Expect scattered showers across the region this morning. Scattered to numerous showers and thunderstorms will then develop across much of the region this afternoon and persist into the evening, most numerous across central and northern areas closer to the stalled front and track of the upper level disturbance. Precipitable water values increase to between 1.50 and 1.75 inches this afternoon. Thus, expect any thunderstorms this afternoon could produce locally heavy rain. The marine layer will help provide more stable conditions along the Downeast coast today where only scattered showers are expected. Areas of low clouds and fog with the marine layer will occur across Downeast areas this morning, locally dense. Patchy fog is expected across northern areas this morning. The low clouds and fog will retreat back toward the Downeast coast this afternoon, though likely remain just offshore or near the shoreline. High pressure centered north of Maine will build toward northern portions of the forecast area overnight with decreasing shower chances. Shower chances will persist Downeast tonight. Low clouds and fog with the marine layer will move back onshore across Downeast areas this evening, then expand northward across the remainder of the forecast area overnight. High temperatures today will range from the upper 70s to around 80 across much of the forecast area. Mid 60s to lower 70s are expected along the Downeast coast with more persistent low clouds and fog along with onshore winds. Low temperatures tonight will range from the lower to mid 60s across northern areas, with upper 50s to around 60 interior Downeast and mid to upper 50s along the Downeast coast. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Saturday and Saturday Night... Challenging precipitation forecast for Saturday into Saturday evening in pinning down where and when the heavier shower activity will be. Airmass will be very moist with precipitable water values from 1.5 to 2 inches. There will be an approaching upper level trough, but this trough is not particularly impressive and will be flattening as it approaches. Marine layer will be in place along/east of the highlands, with most convection not being surface-based except perhaps the western North Woods. Not expecting too much precipitation at the start of the day Saturday, and lowered PoPs for all but the Downeast coast. However, think that shower coverage generally increases through the day as the upper trough approaches and remains more active into the evening, with perhaps a few storms as well but probably nothing severe. Always have to watch out for heavy rain when you have an airmass this moist, but not seeing anything to hang our hat on at this time. Went with broadbrush likely (~60 percent) PoPs with a bit of categorical (80 percent) PoPs western North Woods. Rain totals will vary substantially, with some places getting nothing and some places exceeding an inch, but really can`t pinpoint where the heavier totals will favor at this point. Saturday will be a touch cooler thanks to the cloudcover and showers, with highs mainly in the low to mid 70s. Quite muggy though. Later Saturday night, precipitable water values fall and rain chances decrease. The loss of moisture later Saturday night will mainly be aloft, as the low levels stay moist and again we expect fog for many areas, most prevalent near the coast but possible anywhere. Very mild Saturday night with lows in the mid to upper 60s. Sunday... The upper trough that had been approaching Saturday flattens into upper level WSW flow for Sunday. Still lots of moisture at low levels with a muggy airmass, but less mid/upper level moisture than Saturday. Isolated to scattered mainly afternoon showers and storms expected Saturday...about a 30-40 percent chance of measurable precipitation. Highs back up into the low to mid 80s, except a bit cooler as is often the case for the immediate coast. Still muggy with dewpoints in the mid to upper 60s. Sunday Night... Expect generally dry conditions Sunday night once afternoon convection dies off. However, moist low-levels and light winds could lead to more fog. A touch cooler than Saturday night with lows in the low to mid 60s, which is still easily above average. && .LONG TERM /MONDAY THROUGH THURSDAY/... Warm and muggy weather pattern persists for a while, with nighttime fog common. Can`t rule out showers and storms any day Monday to Thursday, but Monday appears to have the best odds at being dry thanks to subtle ridging aloft and weak subsidence. Went with 20 percent chance of showers/storms Monday afternoon. Next upper level trough begins to approach Tuesday and moves through around Wednesday. Precip chances are around 20-40 percent Tuesday, rise to 40-70 percent Wednesday, then fall to around 30 percent Thursday behind the upper trough. Thunderstorms possible any day, but best chance appears to be Wednesday. Temperatures next week will be warmest Monday and Tuesday, with highs in the mid to upper 80s and some places topping 90 for heat index thanks to muggy conditions. A bit less warm Wednesday to Friday with highs roughly in the low 80s. Nighttime lows remain mild with 60s until perhaps Thursday night, when there is the hope of some 50s thanks to slightly drier air. Models overall are in good agreement in the extended. Some uncertainty in the timing of the next upper trough around Wednesday, but overall pretty reasonable. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... NEAR TERM: Variable conditions this morning, ranging from VFR to VLIFR, with areas of low clouds and fog. Generally VFR/MVFR this afternoon with showers and thunderstorms. Variable conditions possible with any thunderstorms which could produce locally heavy rain. Conditions lower to IFR/LIFR, from south to north, tonight. Areas of VLIFR also possible. Isolated to scattered showers north tonight, scattered to numerous showers Downeast. Variable winds 5 to 10 knots today through tonight. SHORT TERM: Saturday...Fog and IFR cigs may be persistent into the afternoon for coastal sites and as far north as Bangor into midday. Other sites will be MVFR or VFR in the afternoon. Afternoon thunderstorms are possible for all sites. S wind 5-10 kts. Saturday night...Fog and IFR cigs will most likely move north from the coast to affect all sites again. Thunderstorms are possible in the evening. Light S winds. Sunday...IFR cigs will gradually lift to MVFR in the morning and all sites will gradually become VFR in the afternoon. There is a slight chance of thunderstorms in the afternoon for inland locations. W/SW wind 5-10 kts. Sunday night...IFR possible for any site later Sunday night in fog. Light S/SW winds. Monday into Tuesday...Mostly VFR except the threat of nighttime fog and low clouds, most likely near the coast such as at BHB but also possible inland. Light S/SW winds. && .MARINE... NEAR TERM: Winds/seas below small craft advisory levels today through tonight. Visibilities reduced in fog today through tonight. Scattered showers today, with scattered to numerous showers tonight. SHORT TERM: Favorable pattern for marine fog persists into the middle of next week. Winds and seas should remain below small craft levels. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Dense Fog Advisory until 9 AM EDT this morning for MEZ029-030. MARINE...None. && $$ Near Term...Norcross Short Term...Foisy Long Term...Foisy Aviation...Norcross/Foisy Marine...Norcross/Foisy