224 FXUS61 KCAR 091410 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 1010 AM EDT Tue May 9 2023 .SYNOPSIS... High pressure will build across the region through mid-week. A weak disturbance tracks to our southwest on Thursday. A cold front will cross the region later Friday into Saturday morning. High pressure settles in from the northwest on Sunday. && .NEAR TERM /THROUGH TONIGHT/... 1010 AM Update... A cumulus field has developed across the entire forecast area this morning. The atmosphere lacks an abundance of available moisture to support cloud development, but just enough moisture is present around 800 mb as seen on the 12z CAR sounding that fair weather clouds will reside around 5500 feet this morning. Further development into towering cu and showers is unlikely, with the best chance for any shower development being further to the north and east, off into New Brunswick. Even if showers do develop over far northeastern Aroostook, total rainfall will likely remain at a trace at most due to the lack of moisture aloft. Temperatures continue to rapidly rise, and forecast highs were adjusted up slightly to account for this observation and trend. Previous Discussion... Upper level low pressure will remain near Newfoundland today through tonight, while surface high pressure builds toward the region. A disturbance, with limited moisture, rotating around the upper low will also cross the region today. Due to the limited moisture, expect that any showers should remain across New Brunswick. Otherwise, expect mostly/partly sunny skies today. Northwest/north winds will gust to 25 to 30 mph. Expect mostly clear skies tonight. High temperatures today will range from the mid to upper 50s north, to the upper 50s to around 60 Downeast. Low temperatures tonight will range from around 30 to the lower 30s north, to the lower to mid 30s Downeast. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Models are in very good agreement with generally surface high pressure in control with NW flow on the northeast side of 500mb ridging. Expect a dry day on Wednesday with mainly mostly sunny skies. RAP vertically integrated smoke model suggests some upper level haze is possible Wednesday into Wednesday evening thanks to smoke from wildfires in Alberta Canada. Expect a well mixed afternoon with mixing up to 700mb expected. This will allow for relative humidity to fall into the 20-25% range across the area (see the fire weather section below). NW winds will be 10-20mph with some gusts up to 30mph possible. Temperatures will be warmer than today in the low to mid 60s across the north but the downslope of the Longfellow Mtns will allow for upper 60s in Bangor to the Downeast coast. Mostly clear night into Thursday AM with temperatures bottoming out in the mid 40s across the southern 1/2 of the CWA with upper 30s to low 40s across the North. It is a warmer air mass working into the area so the debate was how low do temps get in the morning with light winds, calm skies and dry air. Opted to lower temperatures a degree or two below previous forecast and NBM guidance. During the day model guidance is consistent with a 500mb shortwave diving SE over western New England keeping any extra clouds or showers far to our west. Strong daytime heating combined with 850mb temps warming to between +6C and +8C will result in highs in the 70s nearly CWA wide. Low 70s across the north (minus some upper 60s along Quebec border) and mid 70s for Bangor, Dover- Foxcroft, Danforth and even Bar Harbor. Expecting the NW downslope winds to continue so the only cool spots will be the islands thanks to the colder Gulf of Maine waters. Thursday night expect high pressure to slowly shift southeast around Bermuda which will allow for energy to dive SE in the 500mb flow over Ontario & Quebec. A cold front will be pushing into Quebec during the night. Here in Maine expect generally slowly increasing high cloud cover with temperatures falling back into the low to mid 40s. && .LONG TERM /FRIDAY THROUGH MONDAY/... Friday will be our best chance of precipitation especially across the north and Central Highlands. There remains some model difference of timing of the surface cold front pushing into Maine from the northwest. Very decent agreement on strong warm air advection on southwest winds. Expecting high temperatures in the low to mid 70s from north to south with exception along the Downeast coast where a sea breeze develops late morning. Modeled soundings are suggesting some MUCAPE but this far out only seeing up to 250j/kg. Mid May convection doesn't require too much but there is some question how strong daytime heating will be. For now opted to increase shower chances during the day with likely POPs over the northern 1/2 of CWA by afternoon. Will paint a slight chance of thunder for now based on the soundings. There is some things in the modeled soundings supportive of convection including steep Sfc-3km lapse rates around 8-8.5C/km, 850-500 lapse rates around 7C/km and likely reaching the convective temp around 70-74F. Friday night expecting a chance of showers with the cold front slightly delayed behind the daytime activity. Expect FROPA to occur between midnight and daybreak Saturday given the timing differences. Saturday will be cooler across the north as breezy NW winds develop. Gusts may approach 30-35mph across much of the area as RHs fall back into the 35-40% range. Temperatures will be in the upper 50s to low 60s across the north and downslope of the Longfellows will all for mid to upper 60s in Bangor, Bar Harbor to Calais and points in between. A chance of showers in the morning along the New Brunswick border before becoming a dry afternoon. High pressure will settle in from the northwest on Sunday with mainly another well mixed day with mostly sunny skies. NW winds 15-25mph with some higher gusts, RHs falling back into the 20-30% range and highs in the low to mid 60s. Another system is possible by early next week, however there is significant model differences. This can be seen in the large spread of members predicting the NAO pattern. The PNA is expected to remain positive around +1SD suggesting some troughing but system strength and track will be determined by NAO pattern. At this point given the signature in the operational runs opted to keep NBM slight chance POPs with slightly above normal temps. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... NEAR TERM: VFR conditions today through tonight. Northwest/north winds 10 to 20 knots with gusts up to 25 knots today, except becoming west/southwest along the Downeast coast this afternoon. West/northwest winds 5 to 10 knots tonight. SHORT TERM: Wed-Thu...VFR. Wed expect winds NW 10-15kts with gusts to 25kts possible. Thu expect winds NW winds 5-15kts with a few gusts to 20kts. Fri...VFR. Possible brief MVFR/IFR with scattered SHRA/TS in the afternoon from BGR northward. Chance SHRA at BHB. SW winds 10-15kts. Winds will shift W late evening with FROPA. Sat...VFR/MVFR due to VCSH before noon becoming SKC late day. NW winds 10-20kts with higher gusts possible. && .MARINE... NEAR TERM: Winds/seas below small craft advisory levels today through tonight. SHORT TERM: Winds/seas likely remaining below SCA through the weekend. A few wind gusts to 25kt possible in the evening Wed mainly across far outer waters. Otherwise gusts generally less than 20kt through the weekend. Seas 2-3ft Wed-Thu, 1-2ft Fri- Sun. Fri-Sat there is a chance of showers. && .FIRE WEATHER... No precipitation is expected through Thursday night. Dry Canadian high pressure will provide low afternoon relative humidity through Wednesday generally in the 20-25% range. Minimum relative humidity will begin to recover on Thursday closer to 30%. Northwest winds are expected to remain gusty through Wednesday but not as strong with gusts 20-30 mph possible. Northwest winds will become 10-20 mph by Thursday. Temperatures will be warming through the rest of the week with highs in the 50s to 60F today becoming low to mid 70s by Thursday. Therefore, elevated fire weather conditions are possible through Thursday afternoon. Showers and possible thunderstorms will develop on Friday but a widespread wetting rain isn't expected. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ Near Term...AStrauser/Norcross Short Term...Sinko Long Term...Sinko Aviation...AStrauser/Norcross/Sinko Marine...AStrauser/Norcross/Sinko Fire Weather...Sinko