textproduct: Caribou

WHAT HAS CHANGED

- Updated Aviation Section for the 06Z TAFS.

- Increasing confidence in strong thunderstorm development on Tuesday.

KEY MESSAGES

1) Very warm to hot high temperatures in the upper 80s to low 90s likely Tuesday-Wednesday. Highest apparent temperatures Tuesday for all but Downeast. Downeast, especially coastal areas should see the highest apparent temperatures Wednesday.

2) There is a chance for strong, to possibly severe, thunderstorms over north/central areas Tuesday, continuing into Tuesday night area wide.

DISCUSSION

KEY MESSAGE 1... Very warm to hot high temperatures in the upper 80s to low 90s likely Tuesday-Wednesday. Highest apparent temperatures Tuesday for all but Downeast. Downeast, especially coastal areas should see the highest apparent temperatures Wednesday.

KEY MESSAGE 1 DESCRIPTION... An upper level ridge over the Great Plains will shift to the east as the jet stream moves across the axis. This will pipe very warm temperatures from the western US into the region Tuesday through Wednesday. SW surface flow is expected to bring an additional warm, moist airmass to the region. Temperatures are currently expected to peak Tuesday across all inland areas and Wednesday for coastal Downeast. Moderate humidity with dew points in the 60s to possible low 70s are expected which should push the apparent temperature higher into the mid 90s. A cooldown is likely through the end of the week as cooler air moves in behind a cold front expected to exit off the coast on Wednesday.

KEY MESSAGE 2... There is a chance for strong, to possibly severe, thunderstorms over north/central areas Tuesday, continuing into Tuesday night area wide.

KEY MESSAGE 2 DESCRIPTION... The Storm Prediction Center continues to show a 15% risk for severe thunderstorms on Tuesday for all but coastal Maine. Strong diurnal heating along with increasing SW surface flow will bring temps into the mid/upper 80s in the north and upper 80s to low 90s in the south ahead of the strong surface cold front. In addition, dewpoints should increase into the upper 60s to the low 70s ahead of the front. The factors driving the chance for severe storms include relatively high instability of 1000-2000 J/kg, strong bulk shear of up to 50 kts, and steepening lapse rates. The concern at this point is how severe these storms could get. As of this update, the possible caveat is the timing of the cold front. Some of the ensemble models have slightly inconsistent timing. This could determine if the convection will have enough lift and/or cool air to create the stronger thunderstorms.

Though some diurnal cooling is expected for Tuesday night, the high instability and strong frontal lift could continue thunderstorm development throughout the night. Again, this will depend on the timing of the cold front.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

With the possible exception of a few hours of river valley fog at KPQI and KHUL early this morning, high confidence in VFR through the TAF period.

Light and variable winds through the TAF period, except for a sea breeze this afternoon/early evening at KBHB and early this evening at KBGR. Also a chance for a few hours of W winds at KFVE late this afternoon and a few hours of N winds at KHUL around midday. Wind speeds at both locations should be around 6-7KT.

Late tonight: VFR, with the possible exception of some MVFR river fog at northern terminals.

Monday-Monday night: VFR, except for a brief period of MVFR or lower is possible in any showers/thunderstorms at northern terminals in the afternoon/evening. SW winds G15-20KT possible Monday. LLWS possible Monday night.

Tuesday-Tuesday night...Mainly VFR south, MVFR/IFR north in showers and possible strong TS. The threat could continue into the overnight hours. WSW winds 10-15 kts, becoming W Tue night.

Wednesday...Mainly VFR with possible MVFR/IFR north in afternoon showers and TS. W winds 10-15 kts with gust up to 25 kts.

Wed night-Thursday...Mainly VFR. Possible MVFR north due to showers. W winds 10-15 kts.

MARINE

A weak pressure gradient over all waters out to 60nm will limit winds to 10KT or less and seas to 3 ft or less. The gradient tightens Monday afternoon, with sustained winds up to 15 kt on the coastal waters and 20 kt on the outer waters. There is a chance for gusts to 25-30 kt on the coastal ocean and outer waters Monday afternoon.

Winds and seas are expected to increase Tuesday to SCA levels, then decrease below SCA levels on Wednesday. Seas 4-8 ft Tuesday afternoon to Tuesday night.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Beach Hazards Statement from 8 AM EDT this morning through this evening for MEZ029-030. MARINE...None.