textproduct: Caribou

WHAT HAS CHANGED

- Adjusted thunderstorm coverage for this afternoon mainly away from the Downeast coastline.

- Increased areas of fog Downeast overnight tonight.

KEY MESSAGES

1) Partly to mostly sunny this afternoon leads to scattered showers and thunderstorms, cannot rule out a few stronger storms. Showers taper and lead to more fog tonight.

2) A chance of showers and storms nearly every afternoon from Monday through Friday. However, all-day rainfalls are not expected.

3) Very warm temperatures Monday through Friday and increasingly muggy. Hazardous heat is possible Wednesday through Friday.

DISCUSSION

KEY MESSAGE 1...Partly to mostly sunny this afternoon leads to scattered showers and thunderstorms, cannot rule out a few stronger storms. Showers taper and lead to more fog tonight.

KEY MESSAGE 1 DESCRIPTION... Daytime heating is allowing for cu to build across the area this afternoon with scattered slow moving showers already on KCBW radar data. The 18z RAOB from CAR is already showing some SBCAPE has developed across the area. SPC Mesoanalysis is showing >500j/kg of SBCAPE already with RAP fcsts of up to 1000j/kg which is consistent with the Hi-Res CAMs this afternoon. Expecting these areas of convection to continue building to produce lightning. The 500mb pivoting wave over the area is within a relatively weak flow so steering motion of these storms is less than 15kt. Anything that develops this afternoon and becomes robust has the potential to produce heavy rain with warm cloud processes up to 11kft based on the 18z RAOB from CAR. Additionally PWATs around 1-1.1 inch. Not expecting significant long last robust cores given the weak to moderate lapse rates (low and mid levels). However, cannot rule out heavy rain, small hail and of course deadly cloud to ground lightning. Messaging continues to be, since its a weekend, to keep an eye to the sky for thunderstorms. Showers and storms mainly diurnally driven will taper and end as the sun sets and expecting more fog to develop tonight but uncertainty on how widespread. Winds will remain calm tonight and potential exists for another Dense Fog Advisory.

KEY MESSAGE 2...A chance of showers and storms nearly every afternoon from Tuesday through Friday. However, all-day rainfalls are not expected.

KEY MESSAGE 2 DESCRIPTION... Monday looks quieter for convection. However, as the airmass moistens from Tuesday on, the chance of afternoon showers/storms increases. Also, the center of the upper level ridge axis will remain to our west and we will be under fairly unstable NW flow aloft, and with very warm temperatures and a muggy airmass, this is a very good pattern for severe weather at some point Tuesday to Friday. Hard to tell which day will have the best chance for severe storms, but this is definitely a pattern to watch for. The ridge will be in a nearly perfect position to lead to mesoscale convective systems (MCSs) to ride the ridge into Maine during the overnight hours. Will need to monitor the trends for this potential. As we approach the July 4th holiday a lot of outdoor activities may be impacted by weather.

KEY MESSAGE 3...Very warm temperatures Monday through Friday and increasingly muggy. Hazardous heat is possible Wednesday through Friday.

KEY MESSAGE 3 DESCRIPTION... In addition to the afternoon showers and storms, the heat is another thing to watch out for. There is still some uncertainty just how warm it will get, but at the least we will be looking at is low to mid 80s for highs and upper 50s to mid 60s for lows. The greatest risk for the warmest temperatures is Wednesday through Friday, as on Monday and Tuesday the heat will still be building. Some locations will be getting up to around 90 degrees Wednesday to Friday. In addition, it will be quite muggy and if we get air temperatures up close to 90, heat indices will likely begin to reach heat advisory criteria which is 95. Right now, for each day Wednesday through Friday, the chance of reaching heat advisory criteria (95 heat index) is 25-50 percent, highest in the area from Penobscot Bay Region to Bangor to Dover-Foxcroft, at some point between Wednesday and Friday. In addition, nighttime low temperatures will be quite mild and those without air conditioning will really start feeling the effects later in the week.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

Aroostook Terminals... Tonight: VCSH ends after 03z. Cigs remain predominantly VFR. Vsby down to 4SM, TEMPO 08-12z for KFVE for IFR conditions with vsby down to around 2SM and cigs down to 300-500ft. Winds becoming calm.

Sunday: IFR/MVFR conditions in morning BR will improve quickly to VFR by 12z. Cigs lifting to SCT. Isolated thunderstorms in the afternoon. Winds remain light and variable.

KBGR/KBHB... Tonight...Conditions drop to MVFR cigs around 1500 ft early tonight as winds become calm. Cigs/vsby worsen significantly in BR after 03z for KBHB and 06z for KBGR. FG sets in between 06-08z with VLIFR/LIFR conditions expected. Vsby dropping to 1/2SM at KBGR and 1/4SM at KBHB in FG.

Sunday: VLIFR/IFR fog and low cigs slowly lift to MVFR by 13z-14z, and completely clear to VFR cigs around 3500 ft by 15z-17z. Winds becoming N 5 kt, with SSW 5-10 kt sea breeze at BHB after 15z.

Sunday night-Thursday: Areas of MVFR/IFR in the overnight and early morning hours from fog. Best chance of overnight and early morning MVFR/IFR is closer to the coast, but the possibility will exist anywhere. Generally VFR midday to evening hours except for in heavy showers, with the potential for thunderstorms. There will be a chance of afternoon showers and storms every day except Monday. Winds will be less than 10 kts.

MARINE

Winds/seas below small craft advisory levels today through Sunday. A slight chance of showers this afternoon. A slight chance of afternoon showers and thunderstorms Sunday. Areas of fog today through Sunday.

Through midweek, expecting winds less than 15kt over the waters 25-60nm and seas 2-3ft. Winds/seas below SCA conditions on the Intra-Coastal and Coastal Waters. Fog will reduce vsby less than 1nm at times through midweek on all the waters.

CAR WATCHES/WARNINGS/ADVISORIES

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