textproduct: Caribou

WHAT HAS CHANGED

- 8:11AM UPDATE...Have expired the Dense Fog Advisory as visible satellite shows the fog slowly lifting across the area. KCBW radar data shows the morning convection slowly dissipating and pushing more into New Brunswick. Expecting showers for the next few hours to slowly drift south with the 500mb shortwave creeping into New Brunswick. An additional shortwave located across Quebec will pivot down this afternoon and is expected to reach Maine in time for peak heating today. This will likely lead to scattered thunderstorms and help generate some more robust convection. Hi-Res CAMs continue to show 800-1500j/kg of SBCAPE that is tall and skinny. Dry air aloft in the central portions of the CAPE along with -20C level around 20kft will likely support hail. Inverted "v" signatures at the surface which is supporting gusty wind threat along with DCAPE around 800-1000. Sfc-3km lapse rates around 7.5-8C/km and around 7C/km mid level lapse rates supports robust storms. Cannot rule out a low end severe threat with winds and hail. Additionally, added heavy rain wording to the thunderstorms due to very slow steering today noted by the Corfidi Upshear values 10-15kt. PWATs up in the 1-1.1 inch range and 0C at 10-11kft is favorable with the deep warm cloud process. We will have an 18z upper air sounding to get an idea of the conditions as they develop this afternoon.

KEY MESSAGES

1) Scattered showers and thunderstorms this afternoon and evening. Thunderstorms could produce gusty winds and hail. Dense fog Downeast this morning. 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 gusty winds and hail. Dense fog Downeast this morning.

KEY MESSAGE 1 DESCRIPTION... Upper level troffing will persist across the region today. A disturbance moving through the trof should cross the region during the afternoon, during peak diurnal heating. Dewpoints will reach the upper 50s to lower 60s this afternoon. CAPE values this afternoon will generally range from 600 to 800 J/kg. Scattered showers and thunderstorms will develop this afternoon and persist into the evening. Some thunderstorms could produce hail and gusty winds, with isolated severe thunderstorms also possible. Showers and thunderstorms will then end overnight. Also, a Dense Fog Advisory is in effect for Downeast areas through 8 AM.

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 /12Z SUNDAY THROUGH THURSDAY/

Today: Variable conditions with low clouds and fog this morning. Variable conditions with showers and thunderstorms this afternoon. Some thunderstorms could produce gusty winds and hail. Otherwise, VFR. Variable winds 5 to 10 knots.

Tonight: Variable conditions with evening showers and thunderstorms. Some thunderstorms could produce gusty winds 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-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 Monday. Isolated/scattered thunderstorms this afternoon into the evening. Areas of fog today 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.