Area Forecast Discussion
Issued by NWS Caribou, ME
Issued by NWS Caribou, ME
900 FXUS61 KCAR 181754 AFDCAR Area Forecast Discussion National Weather Service Caribou ME 154 PM EDT Tue Aug 18 2026 .WHAT HAS CHANGED... - Eliminated thunderstorm chances for this (Tuesday) afternoon. && .KEY MESSAGES... 1) Areas of fog again tonight and Wednesday night. Fog could be locally dense at times and impact travel. Dense fog is most likely in low-lying areas. 2) Chance of showers and storms on Wednesday. Showers and storms will be isolated to scattered in nature, with the better chance over North/Northwest Maine. 3) There is the potential for widespread rainfall from Sunday into Monday. It is not certain how much, if any, relief this could bring to the developing drought at this time. && .DISCUSSION... KEY MESSAGE 1... Areas of fog again tonight and Wednesday night. Fog could be locally dense at times and impact travel. Dense fog is most likely in low-lying areas. KEY MESSAGE 1 DESCRIPTION... With very light winds and a moist airmass at low levels persisting, fog is likely again tonight and tomorrow night. While fog this morning tended to cling to the hilltops for inland areas, think that tonight`s fog and lower visibilities will tend to be in lower-lying valleys as the fog will be more of a classic radiation fog. Similar situation in store for Wednesday night. Nighttime dense fog always adds challenges to driving conditions with significant wildlife activity at night. KEY MESSAGE 2...Chance of showers and storms on Wednesday. Showers and storms will be isolated to scattered in nature, with the better chance over North/Northwest Maine. KEY MESSAGE 2 DESCRIPTION... Today`s convection has been a dud so far, so lowered shower chances and eliminated thunder chances for the rest of this afternoon. For Wednesday, there should be just enough instability and lift ahead of a weak approaching cold front that there could be some afternoon showers/storms. Chances however are generally 30 percent or less, with the better storm chances over North/Northwest Maine. We don`t expect any of the storms to be on the stronger side. KEY MESSAGE 3...There is the potential for widespread rainfall from Sunday into Monday. It is not certain how much, if any, relief this could bring to the developing drought at this time. KEY MESSAGE 3 DESCRIPTION... A closed low tracks from near the Great Lakes on Sunday to southwestern Quebec/Northern New England by Monday evening. Based on the ensemble consensus would expect warm advection rain, with embedded convection from Sunday through Monday. The latter is most likely in the afternoon/early evening. At this point in time, given the inherent uncertainty in days 6 and 7 in the forecast, plus the added uncertainty given the storm type (even if somewhat mitigated by a degree of consensus in the ensembles), it is to early to state what, if any, impacts this system may have on the region. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/... Rest of Today... As of 18z, a few spots are clinging to MVFR cigs (such as BHB/BGR), but expect them to rise to VFR within a couple hours. Otherwise VFR. Shower chances have decreased from what was previously thought, and thunderstorm chances have been eliminated, and removed prob30 from TAFs. Light and variable winds generally less than 10 kts. Tonight and Wednesday Night... Fog likely both tonight and Wednesday night after roughly 2-5z especially in lower lying places. Tough to pinpoint which TAF sites will get it and which won`t. Of the sites we do TAFs for, think that CAR and FVE have the lower probabilities since they are on hilltops, but fog is possible at these sites too. Light winds. Wednesday... Generally VFR once any AM fog burns off. About a 20 percent chance of showers at any TAF site in the afternoon, with a 10-15 percent chance of a thunderstorm mainly at PQI/CAR/FVE. SW wind 5-10 kts. Wednesday night: MVFR or lower possible in patchy fog or any convection ahead of the cold front, then becoming VFR overnight. Thursday-Saturday: VFR. Sunday: MVFR/IFR in rain showers. E winds 5-10 kts. && .MARINE... Intermittent fog over the waters through Wednesday night, more prevalent during nighttime hours. Fairly light winds through Wednesday night. Seas to increase to about 4 ft tonight as a S swell. Cannot rule out seas to 5 ft, but not enough confidence to issue any small craft advisory. A relaxed pressure gradient over the waters from Thursday through Saturday should allow for winds of 10kt or less and seas of 4 ft or less across the waters out to 60nm. Sunday could see an increase in winds up to 15 kts with 2-4 ft seas. Rain showers with possible afternoon thunderstorms expected. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...None. && $$ DISCUSSION...TF/ARL AVIATION...TF/ARL