482 FXUS61 KCAR 291920 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 320 PM EDT Mon Jun 29 2026 .WHAT HAS CHANGED... - Increased chance for afternoon thunderstorms through the second half of the week, some of which may be strong to severe && .KEY MESSAGES... 1) Complex of thunderstorms possible Tuesday night, mainly over western areas. 2) Very warm temperatures through Friday and increasingly muggy. Hazardous heat is possible Wednesday through Friday, with little reprieve each night. 3) Building heat and humidity will provide fuel for thunderstorms each afternoon, some of which could be severe. && .DISCUSSION... KEY MESSAGE 1...Complex of thunderstorms possible Tuesday night, mainly over western areas. KEY MESSAGE 1 DESCRIPTION... MCV likely to be approaching the CWA Tuesday evening over top of the H5 ridge Tuesday evening. Guidance remains all over the place wrt location but all continue to indicate a complex of storms moving thru Tuesday night. Looking at the instability parameters as the storms enter the area expect that most will be elevated, except maybe closer to western zones with better surface-based instability. For the time being have gone with only likely pops for Tuesday night due to inability to specify one location vs another. Western zones currently in a marginal excessive rainfall outlook given PW values > 2.00 inches. KEY MESSAGE 2...Very warm temperatures through Friday and increasingly muggy. Hazardous heat is possible Wednesday through Friday, with little reprieve each night. KEY MESSAGE 2 DESCRIPTION... Hot temperatures are expected this week, with the highest temperatures landing Wednesday through Friday. This heat combined with the increase in humidity could result in hazardous heat beginning Wednesday, particularly for the Bangor area, Central Highlands around Dover-Foxcroft, and the Interior Downeast region. In addition to the daytime heat, lows each night will only drop into the upper 60s to lower 70s. Combined with dewpoints of about the same, warm and humid nights are expected which will offer little reprieve after the daytime heat. This could increase the stress and hazardous effects this heatwave has. For Wednesday, southerly winds will bring marine moisture up into the region, with dewpoints quickly lifting into the upper 60s to lower 70s. Meanwhile, temperatures under the ridge of high pressure will easily lift into the 80s throughout the forecast area, though some portions of the Bangor and Interior Downeast region could lift into the upper 80s and approach 90. For Thursday, winds shift in direction to out of the west, reducing the marine influence on the area and introducing some downsloping out of the Longfellows. This pattern shift will allow for dewpoints to level off some, however temperatures will continue to climb. Thursday will likely be the hottest day of the week, with the northern half of the forecast area reaching into the upper 80s to lower 90s and the Bangor and Interior Downeast regions potentially making a run for the mid 90s. The immediate coast may hold onto some marine influence and not see quite so extreme of heat. For Friday, temperatures decrease some, and winds become more northwest, increasing the downsloping effect on keeping dewpoints from rising out of the lower 70s Downeast. KEY MESSAGE 3... KEY MESSAGE 3 DESCRIPTION...Building heat and humidity will provide fuel for thunderstorms each afternoon, some of which could be severe. The center of the upper level ridge will be positioned south of our area, allowing for waves of energy to ride over top of the ridge and provide a source of instability each day through this week. Additionally, hot temperatures along with increased humidity will supply ample fuel to support convective initiation. Indeed, NBM forecast CAPE values each afternoon reach around 1000 J/kg throughout our forecast area. Though the exact mesoscale parameters remain uncertain at this time scale in terms of the exact threat for strong to severe thunderstorms, the synoptic environment could support stronger storms each afternoon. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... Tonight...VFR. Only exception expected to be BHB with MVFR vsbys in fog between 09-12z. Cannot rule out brief IFR vsbys at PQI and HUL but confidence is too low to include at this time. Light and variable winds becoming near calm overnight. Tuesday...Mainly VFR though cannot rule out potential MVFR in showers and tstms in the afternoon across the north. WSW winds 5kts. Tuesday night...MVFR/IFR in locally heavy rain and tstms. mainly affecting Downeast terminals. SSW winds 5-10kts. Tuesday night-Wednesday night: VFR, except for a chance of MVFR or lower in any fog late at night/early in the morning and a brief chance for MVFR in any stronger convection in the afternoon/early evening. S/SW winds at 5-10 kt, gusts to 15 kt. Thursday-Friday: VFR, except for a chance of MVFR or lower in any fog late at night/early in the morning and a brief chance for MVFR in any stronger convection in the afternoon/early evening. W winds at 5-10 kt, gusts to 15 kt. Winds shift NW on Friday. Saturday: VFR/MVFR BKN skies with -SHRA possible most of the day. Lower conditions possible in any more moderate rain or thunderstorms. W winds 5 to 10 kts. && .MARINE... Wind and seas will remain below small craft levels through Tuesday. SW winds gusts to aoa 25kts over waters 25-60NM after midnight with seas approaching 5ft out to 25NM and between 6-8 feet from 25 to 60NM. Visibilities to reduced in fog over the waters tonight and again Tuesday night. Seas may increase Tuesday night into Wednesday, becoming 4 to 7 ft. Winds should remain below advisory level during this time though, with gusts 15 to 20 kts aside from the outer waters, which could see gusts to 25 kts. Seas decrease once more through the rest of the week. Chance for fog to reduce visibility through the middle of the week. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ DISCUSSION...AES/21 AVIATION...AES/21