textproduct: Caribou

WHAT HAS CHANGED

- Cancelled SCA.

- Updated Aviation Section for 12Z TAFs

KEY MESSAGES

1) Soaking morning rainfall along a slow-moving cold front will give way to partly sunny skies later today, with lingering scattered showers and isolated thunderstorms expected across Northern Maine.

2) Localized flooding is possible Thursday through Thursday night.

DISCUSSION

KEY MESSAGE 1...Soaking morning rainfall along a slow-moving cold front will give way to partly sunny skies later today, with lingering scattered showers and isolated thunderstorms expected across Northern Maine.

KEY MESSAGE 1 DESCRIPTION... Regional radars across the region shows an area of moderate to embedded heavy rainfall ahead of an approaching cold front. KCBW radar shows the rain mainly confined across Northern Maine this AM with slow eastward progress. There is some thunderstorms around the Moosehead Region producing lightning as noted by the GLM, ground obs and webcams. As of 2AM EDT the cold front was crossing the Champlain Valley of Vermont and up into Southern Quebec pushing east towards us. Rain is tracking NE along the boundary which is favorable to create the potential for training heavy showers. PWATs ahead of the front are still in the 150-175 percent of normal range, hi- res soundings showing warm cloud processes up to 8-9kft (not as favorable for +RA) and weakening elevated instability. Although, flash flood threats have come down significantly from previous forecasts the concern is the antecedent conditions of soaked soils may lead to an excessive runoff concern. 1hr FFG as of 06z showing 1-1.5 inches of rain in the Central Highlands and Northern Maine with 3hr FFG around 1.5-2 inches. Although, the likelihood for a short fused flash flood warning has significantly fallen cannot rule out the need for flood advisories.

The cold front will slowly make it to the Maine/New Brunswick border between 1PM-3PM this afternoon bringing an end to the widespread rainfall. However, 500mb shortwave pivoting out of Quebec into Northern Maine with some afternoon destabilization from sunshine may result in some scattered showers and isolated thunderstorms mainly across Northern Maine. High temperatures top out in the upper 60s to mid 70s with the warmest spots getting the most sunshine in western zones.

KEY MESSAGE 2...Localized flooding is possible Thursday through Thursday night.

KEY MESSAGE 2 DESCRIPTION... A large and seasonably strong low pressure system is expected to progress NE across the Great lakes and into Canada on Thursday. Rain is generally expected to begin by mid-day Thursday but some uncertainty still exists in the global models. Guidance is showing a strong low-level jet developing Thursday evening which will bring ample low-level moisture into the area and could contribute to some decent rainfall amounts. Ensembles are currently suggesting around a 60% chance of at least 0.5" of rain with PWAT values approaching the 90th percentile. As a result, some localized flooding, especially where any thunderstorms may develop, is possible, but it is too early to be more definitive on how great the risk is. The questions will be how much moisture can advect into the area ahead of the system. Also, if the low retrogrades at all, then the rain bands will slow down, allowing them to stick around localized areas, which could increase the flooding risk.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Becoming MVFR or lower at all terminals this morning. Conditions should improve to VFR throughout by late this afternoon/early this evening. SE-SSW winds around 10KT to get started become light and variable throughout by mid-late afternoon. NW winds 6-9KT possible KFVE and KBGR tonight. LLWS at KBHB this morning.

Tuesday-Wednesday: VFR. NW winds G15KT possible Tuesday morning.

Wednesday night-Thursday: IFR or lower likely. Locally heavy rain Thursday. S-SE winds G15-20-25KT possible Thursday. LLWS possible at southern terminals Thursday.

Thursday night-Friday: IFR initially with possible improvement to MVFR at southern terminals early Friday morning, then gradual improvement throughout the day. Locally heavy rainfall possible early. LLWS possible Thursday night. WSW-W winds G15KT possible Friday.

MARINE

Buoys showing wind gusts below 25KT, including upstream immediately ahead of the cold front, so no longer have an expectation for frequent gusts to 25KT on the coastal ocean waters. As a result have cancelled the SCA for there. Winds are gusting 25-30kt across the outer waters (25-60nm) but we do not issue SCAs per NWS policy in these zones. Waves 4-5ft in those outer waters this morning. Winds will relax today to 15 kt or less by late afternoon, with seas subsiding in all waters to 2-4ft. These conditions should then continue through Tuesday.

Winds and seas below small craft advisory criteria Tuesday night through Thursday morning then winds and seas increase above criteria on all waters Thursday afternoon through Thursday night. Seas remain elevated through Friday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...None.