textproduct: Caribou

WHAT HAS CHANGED

- Blended NBM/ConsShort POPs this morning to adjust the timing of the rain across the CWA.

- Increased the isolated thunderstorm coverage this afternoon across Northern Maine.

- Increased confidence in a strong low pressure system passing to our north Thursday which is likely to bring locally heavy rain and possibly some thunderstorms.

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. Given this opted to keep the Flood Watch for flash flooding continuing for the Central Highlands into Northern Maine through 8AM EDT.

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 /06Z MONDAY THROUGH FRIDAY/

Before 12z This AM: Northern Terminals (KFVE, KCAR, KPQI, KHUL): Conditions deteriorating to MVFR/IFR with -RA and BR (KFVE remaining LIFR). SE to S winds 10 to 15 kt with gusts 20 to 25 kt. LLWS likely at KHUL. KBGR: VFR lowering to MVFR/IFR around 09z in -RA and BR. PROB30 for -TSRA. S winds 10 kt gusting 20 kt. LLWS likely. KBHB: VFR dropping to MVFR by 10z with -RA. S winds 10 kt gusting to 20 kt. LLWS likely.

Today: Northern Terminals: IFR in -RA/-SHRA and BR through the morning and early afternoon. Gradual improvement to MVFR after 18z-19z. PROB30 for -TSRA at KFVE between 18z and 23z. S winds 10 to 15 kt gusting to 20 kt early, shifting SW 5 to 10 kt this afternoon. KBGR: IFR in -RA and BR this morning, improving to MVFR by 16z, and becoming VFR by 18z. S winds 10 kt shifting NW around 5 kt this afternoon. KBHB: Lowering to IFR/LIFR by 13z in -RA and BR. Improving to MVFR by 17z. S winds 10 kt shifting NW around 5 kt late.

Tonight: Northern Terminals: Generally VFR with W to NW winds around 5 kt. The exception will be KHUL, where BCFG may drop conditions back to IFR/LIFR. KBGR: VFR. NW winds around 5 kt. KBHB: MVFR ceilings lingering early, becoming VFR after 03z. NW winds around 5 kt.

Tuesday-Wednesday...VFR. Light and variable winds becoming S at 5 to 10 kts Wednesday.

Wednesday night-Thursday...Conditions decrease to IFR first at southern terminals overnight in possible fog. Locally heavy rain Thursday. S winds increasing to 10 to 15 kts with gusts 20-25 kts. 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. S winds 10 to 15 kts early, becoming W Friday.

MARINE

Small Craft Advisory for the Intra-Coastal Waters till 6AM for S wind gusts up to 25kt. Small Craft Advisory for the Coastal Waters till 2PM this afternoon for S winds gusting up to 30kt and seas 3-5ft. Winds are gusting 25-30kt across the outer waters (25-60nm) but we do not issuing SCAs per NWS policy in these zones. Waves 4-5ft in those outer waters this morning. Winds will relax today with seas subsiding in all waters to 2-4ft.

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...Flood Watch until 8 AM EDT this morning for MEZ001>006-010-011- 031-032. MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ050- 051. Small Craft Advisory until 6 AM EDT early this morning for ANZ052.