textproduct: Caribou

WHAT HAS CHANGED

- Adjusted thunderstorm coverage into this evening based on the trends of KCBW data and Hi-Res CAMs.

KEY MESSAGES

1) Scattered showers and thunderstorms this afternoon and evening. Thunderstorms could produce heavy rain, gusty winds and hail. 2) A chance of showers and storms nearly every afternoon from Tuesday 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...Scattered showers and thunderstorms this afternoon and evening. Thunderstorms could produce heavy rain, gusty winds and hail.

KEY MESSAGE 1 DESCRIPTION... 18z upper air sounding from CAR showing 1570j/kg of CAPE with steep low level lapse rates, decent mid level lapse rates that will support convection this afternoon. We are in peak heating right now and have reached convective temperatures. KCBW data shows multiple areas of isolated to scattered storms and expecting more to develop as a 500mb shortwave approaches from the NW. Terrain will also play a role in helping 18z sounding and Hi- Res CAMs confirm very little steering flow so storms will rapidly bubble up and with very little shear storms will collapse rather easy. Given the PWATs around 1-1.1 inch and 0C up at 10-12kft across the CWA expecting heavy rain with these storms. Additionally, dry air aloft in the hail growth zone will support development of at least some small hail and inverted "v" signature with DCAPE around 750-900 means the potential exists for gusty winds. This would be expected with collapsing water/hail heavy cores so cannot rule that out. Have opted to include enhanced wording through to sunset. These storms are diurnally driven so expecting activity to quickly end by sunset.

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. As of now, Thursday seems to have the highest heat index of the three days. 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 /18Z SUNDAY THROUGH FRIDAY/

Rest of Today: Variable conditions with showers and thunderstorms this afternoon. Some thunderstorms could produce gusty winds, heavy rain and hail. Otherwise, VFR. Variable winds 5 to 10 knots.

Tonight: Variable conditions with evening showers and thunderstorms. Some thunderstorms could produce gusty winds, heavy rain and hail. Variable conditions with fog overnight. Otherwise, VFR. Variable winds 5 to 10 knots.

Monday: Variable conditions with any fog early. Otherwise, VFR. Variable winds 5 to 10 knots.

Monday night-Friday: 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 Monday. Isolated/scattered thunderstorms this afternoon into the evening mainly across the Intra-Coastal Waters and Coastal Waters near the Downeast coast. Areas of fog into Monday.

Through next week, 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 visibility less than 1nm at times through midweek on all the waters.

CAR WATCHES/WARNINGS/ADVISORIES

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