Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
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716 FXUS61 KCAR 291754 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 154 PM EDT Sat Jun 29 2024 .SYNOPSIS... High pressure will slowly exit to the east today. A warm front lifts to the north Saturday night, followed by a cold front crossing the region from Sunday into Sunday night. High pressure then builds through Wednesday. && .NEAR TERM /THROUGH TONIGHT/... 155 pm update... Have tweaked pops slightly with this update along with lowering high temps acrs the south and west while increasing them over the northeast. Previous discussion... High clouds will thicken and lower throughout the day as a warm front approaches from the west. These clouds will reduce surface heating compared to yesterday. Highs will reach the lower 70s in Aroostook County, but an onshore flow will limit highs to the mid to upper 60s towards the coast. An usually powerful low level jet arrives from the southwest in the afternoon with a magnitude near 60 kt at 850mb. This will be mostly in northern zones. While the thickening high clouds will dampen mixing somewhat, gusts to 40 mph are still possible in the afternoon from the south to southwest. Chances for precipitation will increase by the mid to late afternoon as very dry air under H7 is finally overcome. The LLJ continues moving over the area through the night, but concerns shift from strong surface winds to anomalously high moisture transport with the warm front. Precipitable water values surge towards 2 inches Saturday night with a deep warm cloud layer nearing 13 to 14k ft. Elevated instability increases through the night as a low level thermal ridge builds into the area. 850mb temps may reach up to 17C by later in the night. As a result, will mention thunderstorms through the night with the warm front. Heavy rain is also a threat. Expect generally less than an inch, but amounts could be locally higher with embedded convection. The warm front will introduce very warm and humid air by late night with dew points climbing into the mid to upper 60s by early Sunday morning. This moisture will likely generate fog under the frontal inversion later in the night into early Sunday morning as winds decrease. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... A cold front will move through the region on Sunday, bringing showers and strong thunderstorms to the area. For the morning, rain showers from Saturday night will continue. SW winds will continue to be breezy. The 925-850mb model temps show the morning temps climbing into the 60s early. By the afternoon, the cold front is expected to quickly move into the region by early afternoon and progress into the Central Highlands by the middle of the afternoon. The concern will be the rapidly increasing instability ahead of the front. Upper air model soundings indicate a corridor of high CAPE values >1000 J/kg from Central Aroostook, through the Central Highlands, and into the Bangor Region by the afternoon. This line of CAPE should progress from the NW to SE. In addition with the high CAPE, is the high bulk shear values of >40 kts that will help support stronger updrafts, producing gusty winds and hail. Some of these storms are expected to be severe. Confidence has increased with the expansion of the Slight risk of severe thunderstorms by SPC. By Sunday night, the front should exit over the waters. As high pressure moves in, clouds should begin the clear and NW flow should decrease. High pressure is expected to remain in the areas through Monday and Monday night, keeping skies fairly clear and temps near normal. && .LONG TERM /TUESDAY THROUGH SATURDAY/... High pressure remains in the area through much of next week, making for inactive weather. The next systems is expected to move into the region on Thursday in the form of a cold front. Models are in better agreement with the track and of the front, but still inconsistent with the timing. Decided to go with chance showers. Thunderstorms are also possible, but did not include with this update due to lower confidence in the cold front timing. High pressure should return for the end of the week. Temps should be on a warming trend with above normal temps. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... NEAR TERM: VFR diminishing to MVFR/IFR this evening. Rain moves in after 00z tonight with IFR fog/cigs impacting terminals late this evening. Cannot rule out VCTS at BGR late but very little confidence to include with this forecast. LLWS will be present at all terminals tonight at FL020 from the south 40-55kts. SHORT TERM: Sun...MVFR/IFR, then becoming VFR afternoon. TSRA expected. S to SW wind G20 to 25 kt, then becoming NW late. Sun night...MVFR possible KBGR/KBHB early in lingering TSRA, otherwise improving to VFR. NW winds 5-10 kts. Mon through Wed...VFR. NNW winds 5-10 kts, then light and variable Tue night. S winds 5-10 kts Wed. && .MARINE... NEAR TERM: In spite of the usual strong summer stability and steep inversion, Saturday night winds will still be more than sufficient to generate a Small Craft Advisory. In response to winds gusting to 30 kt, seas will build to over 7 feet Saturday night. In addition, fog and thunderstorms can be expected Saturday night. Inexperienced mariners should avoid navigating in these hazardous conditions Saturday night. The Small Craft Advisory begins Saturday evening and continues through the night. SHORT TERM: SCA conditions are possible Sun through Sun night, otherwise expect below SCA conditions the remainder of the period. Visibility will be reduced to 1 to 3 NM in any showers and thunderstorms on Sunday. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory from 8 PM this evening to 2 AM EDT Monday for ANZ050>052. && $$ Near Term...Buster/MCW Short Term...LaFlash Long Term...LaFlash Aviation...Buster/MCW/LaFlash Marine...Buster/MCW/LaFlash