textproduct: Caribou

WHAT HAS CHANGED

- 740 PM Update: Delayed patchy fog development and start to rain based on current relative humidity observations and amount of dry air to be saturated. Updates to aviation section below with the 00z TAFs.

- Lowered dew points for this afternoon.

- Slowed the onset of POPs this evening due to significant dew point depressions.

- Increased QPF for Downeast locations.

- Added isolated embedded thunderstorms along the Downeast coast for Monday afternoon.

KEY MESSAGES

1) Widespread soaking rain from tonight into Memorial Day. This will aid in mitigating ongoing drought conditions across portions of the region.

2) Showers likely with possible thunderstorms late Tuesday afternoon and Tuesday evening over Northern Maine.

3) Cooler temperatures expected later in the workweek, with unsettled weather likely continuing.

DISCUSSION

KEY MESSAGE 1...Widespread soaking rain from tonight into Memorial Day. This will aid in mitigating ongoing drought conditions across portions of the region.

KEY MESSAGE 1 DESCRIPTION... Ridge axis and dry air and 30-40 degree dew point depressions will be exiting to the east on this evening. As the airmass moistens, rain is expected to begin late this evening to early tonight. This is a significantly dry airmass its running into so have once again slowed POPs timing. The rain will then spread from W to E through the night and into Memorial Day. Cold air damming overnight will essentially split the rain between south and north early in the overnight hours before moisture converges over the CWA.

A cold front will cross the area during the day on Memorial Day, bringing a wetting rain across the region. Total rainfall amounts will be highest along the coast as a coastal low develops along the surface trough, enhancing forcing along the coast. Even still, total rainfall will likely remain below an inch through the area, though overcast skies and increased moisture will limit evaporation and add to the surface moisture likely improving ongoing drought conditions. Have opted to add embedded thunderstorms along the Downeast coast with some elevated instability that works into that region associated with developing surface cyclogenesis. Rain will end W to E as a few showers. Given the rainfall and with diminishing winds tomorrow night, patchy valley fog is possible Monday night mainly in valley locations.

KEY MESSAGE 2...Showers likely with possible thunderstorms late Tuesday afternoon and Tuesday evening over Northern Maine.

KEY MESSAGE 2 DESCRIPTION... Confidence is fairly high in a quick hitting system impacting mainly northern portions of the area Tuesday afternoon into the evening. The timing of the shortwave trough approaching from the northwest looks to favor most of the activity being after 6PM, with shower chances peaking in the evening. Thunderstorms are also possible, but confidence is low to moderate on this due to the timing before sunset. Much of the instability that does develop will quickly dwindle as the sun sets around 815PM. Rain totals don't look overly impressive, with generally a tenth to a quarter of an inch of rain north of Baxter SP/Moosehead Regions, none for Bangor to the coast. Locally higher amounts are possible in any thunderstorms over the north.

KEY MESSAGE 3...Cooler temperatures expected later in the workweek, with unsettled weather likely continuing.

KEY MESSAGE 3 DESCRIPTION... From Wednesday onward, forecast confidence decreases, specifically in timing individual systems. That said, we do have fairly high confidence in below normal temperatures from Thursday to Saturday, and confidence in a pattern which features unstable north/northwest flow with periodic shower chances. If we can get a clear night, we can't rule out patchy frost mainly in Northern Maine on any of the nights Thursday night to Saturday night. There's about a 20-30 percent chance that one of the nights in this timerange would have patchy frost.

AVIATION /00Z MONDAY THROUGH FRIDAY/

00z TAF UPDATE...

KBGR and KBHB/coastal terminals: VFR conditions will persist through the evening, with mid-level clouds thickening and lowering. Will drop to MVFR around midnight with VCSH. Conditions will rapidly deteriorate to IFR, and eventually LIFR over the next few hours with the onset of light RA. A prominent hazard overnight will be around 40 kts of SE LLWS. Additionally, slight chance of isolated thunderstorms Monday afternoon at coastal terminals.

KCAR, KPQI, KHUL, KFVE/northern terminals: VFR into this evening, generally lowering to MVFR shortly after midnight, quickly followed by IFR as the precip shield moves north. Widespread LIFR conditions are expected by Monday morning with light rain lowering cigs. LLWS through the morning is possible, though not as strong as near the coast.

All Terms Winds: S winds 5-15kt with gusts up to 20kt through this evening. Winds will generally remain from the S-SE at 5-10 kt into overnight, with some localized gusts to 20kt returning tomorrow morning.

Monday Night...Generally VFR, but with patchy valley fog which could produce local IFR/LIFR. Confidence is low. Light and variable winds.

Tuesday...W/SW wind 10 kts gusting 20 kts. VFR, except possible MVFR late afternoon in the far north with potential for thunderstorms.

Tuesday Night...MVFR possible from HUL north in showers and possible storms. Likely VFR BGR/BHB. S wind 5 kts.

Wednesday and Thursday...Mainly VFR BGR/BHB and MVFR or VFR HUL/PQI/CAR/FVE. Showers possible. NW wind 5-15 kts with higher gusts during the day.

Friday...VFR/MVFR with showers possible. N winds 5-15kt.

MARINE

Winds/seas below SCA conditions into this evening. SE winds will ramp up tonight gusting >25kt by midnight across the outer waters 25-60nm then gusting over 25kt on the coastal waters on Monday. Small Craft Advisory in effect for the Coastal Waters out 25nm from 5AM Monday till 8AM Tuesday. SE winds 10-20kt with gusts up to 30kt and seas building to 5-8ft. On the intra- coastal waters the Small Craft Advisory is in effect from 11AM Monday till 2AM Tuesday. Southeast winds 10-20kt with gusts up to 25kt and season 3-6ft. Rain and fog develops across the waters tonight and last into Monday evening. Thunderstorms are possible on Monday afternoon embedded within the rain. Fog remains possible Monday night into Tuesday.

Winds relax to generally less than 25kt across the waters Tuesday AM through late week. Seas 3-5ft Monday night into Tuesday evening then subside towards 1-3ft by mid to late week. Chance of showers returns late week.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory from 5 AM Monday to 8 AM EDT Tuesday for ANZ050-051. Small Craft Advisory from 11 AM Monday to 2 AM EDT Tuesday for ANZ052.