textproduct: Caribou

WHAT HAS CHANGED

- Added mention of possibility for smoke tonight into Monday behind FROPA

KEY MESSAGES

1) Scattered showers and thunderstorms this evening, with some thunderstorms potentially becoming severe. Stronger showers and storms may produce locally heavy rainfall, with the potential for localized flooding.

2) Scattered rain showers and thunderstorms Monday through Tuesday, with some locally heavy rainfall possible. Smoke possible in between rounds of rain.

DISCUSSION

KEY MESSAGE 1... Scattered showers and thunderstorms this evening, with some thunderstorms potentially becoming severe. Stronger showers and storms may produce locally heavy rainfall, with the potential for localized flooding.

KEY MESSAGE 1 DESCRIPTION... A northern stream shortwave trough moves across southern Quebec today, with a surface cold front moving through the CWA early this evening. The 18z KCAR sounding indicates CAPE has surged over 2000 J/kg this afternoon, which is supporting TCu and shower development with a couple of thunderstorms so far. However, limited shear is evident, as showers and storms are fairly ordinary and though they are not collapsing right away, they are unlikely to grow into much more.

Still, with PWATs around 1.5 inches, the chance for heavy rainfall remains closely monitored, along with the chance for any gusty winds or the potential for an isolated wet microburst.

KEY MESSAGE 2...Scattered rain showers and thunderstorms Monday through Tuesday, with some locally heavy rainfall possible. Smoke possible in between rounds of rain.

KEY MESSAGE 2 DESCRIPTION... Rounds of shortwaves move to the north this week, bringing a chance for rain showers and some thunderstorms. Thunder possible in the north on Monday, area wide Monday night, and in the north on Tuesday. More showers are possible late week. Looking at potential for 500 to 1000 J/kg of surface based CAPE and 25 to 35 kts of shear. With a persistently moist air mass in place and PWATs often exceeding 1.5 inches and combined with weak mid level lapse rates, severe potential may be marginal at best. However, any stronger showers or storms that do develop through peak heating hours could return the threat for localized moderate to heavy rainfall.

Current satellite imagery shows a plume of wildfire smoke filling in behind the front throughout southern Quebec and down through central New England. HRRR and RAP smoke models indicate that this could translate to surface smoke in our area Monday afternoon, and could slightly limit visibility.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Tonight-Monday: VFR, with a low chance of MVFR in any passing shower or thunderstorm Monday afternoon. Low chance for IFR conditions at KBHB/coastal terminals in fog or low stratus late tonight. The best chance of a shower or storm is from KHUL on north. Winds light and variable overnight becoming SW 5 to 10 kts by Monday afternoon. Smoke behind the cold front could slightly reduce vis across all terminals as well, but current guidance suggests it is unlikely to see vis fall below 6 SM.

Monday night-Tuesday: MVFR/IFR in showers late Monday night and Tuesday afternoon, otherwise VFR across all terminals. Winds light and variable Monday night, becoming W 5 to 10 kts with gusts up to 20 kts Tuesday afternoon.

Tuesday night-Wednesday: VFR overnight. Winds W at 5-10 kt.

Wednesday night-Thursday: MVFR/IFR possible in any showers. Winds W/SW at 5-10 kt.

Friday: VFR across all terminals, with brief MVFR possible at northern terminals in any showers or storms. NW winds 10 to 15 kts with gusts 20 to 25 kts.

MARINE

Winds should be 15 kt or less and seas 3 ft over the waters out to 60nm through Thursday.

Fog reducing visibilities to 1nm or less is likely over the waters through this morning. There is also the potential for some showers from Monday into Tuesday. There is a chance for thunderstorms over the waters on Thursday.

CAR WATCHES/WARNINGS/ADVISORIES

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