textproduct: Caribou

WHAT HAS CHANGED

- Raised forecast high temperatures for today

KEY MESSAGES

1) Warm and dry conditions continue today and Tuesday.

2) Significant rainfall is possible Thursday into Friday, which should be beneficial for the ongoing groundwater drought.

DISCUSSION

KEY MESSAGE 1...Warm and dry conditions continue today and Tuesday.

KEY MESSAGE 1 DESCRIPTION... Warm temperatures are expected again today and Tuesday as the 500mb ridge axis just west of the area today shifts overhead on Tuesday. 850 mb temperatures around 3 to 5C will yield surface temperatures well into the 60s, with potentially a few spots across the Penobscot valley touching 70 degrees today under strong solar heating and very light winds. Winds shift south on Tuesday leading to more marine induced cooling across coastal areas and Downeast Maine where some locations closer to the coast may struggle to get out of the 60s despite ample sunshine. South winds around 10 to 15 mph, combined with decreasing relative humidity in the 20 to 30 percent range and recent dry weather, could lead to elevated fire danger. If considering burning please consult the Maine Forest Service website or listen to NOAA Weather Radio where ratings are broadcast each morning.

KEY MESSAGE 2...Significant rainfall is possible Thursday into Friday, which should be beneficial for the ongoing groundwater drought.

KEY MESSAGE 2 DESCRIPTION... Broad upper level troughing pivots over the Great Lakes into Ontario during the middle of the week. At the same time ridging will erode over Maine Tuesday night into Wednesday and move northeast to just south of Greenland, creating strong blocking which will cause the trough progression to slow and eventually become cut-off. At first some lighter rain is possible Wednesday, especially along the coast and Downeast areas, associated with a weak onshore push of moisture. On Thursday, a shortwave rounding the base of the trough will foster the development of a surface low off the mid-Atlantic coast. The low is expected to strengthen while moving northeastward. Ensemble members are still in disagreement over exactly where it tracks and when it reaches Maine but the consensus is for the low center to track somewhere in the vicinity of the coast. Ample moisture is expected to be associated with this system as PWATs will be approaching the 90th percentile for this time of year. This should lead to ample rainfall with ensemble means showing somewhere around 2 inches in some locations with a few higher end solutions showing localized areas of 3 to 4 inches. Generally thinking that some of these higher end solutions will not come to fruition as freezing levels around 6 to 7kft will favor less efficient cold rain processes and there will likely not be any elevated convection. Currently thinking there may only be minor flooding concerns, especially given the persistent drought, but that the several inches of rain expected could help alleviate some of the deficit in the groundwater.

Heavier PWATs move east of the area by the weekend, but unsettled weather will continue with the upper level low likely to remain overhead and cause below normal temperatures and elevated chances for cloudier skies and showers, possibly into early next week.

AVIATION /06Z MONDAY THROUGH FRIDAY/

VFR with light winds through Tuesday.

Tuesday night to Wednesday: VFR, becoming IFR at southern terminals Tuesday night and MVFR at northern terminals Wednesday with -SHRA and -DZ possible. Patchy FG also possible at southern terminals. SSE winds 5-10 kt.

Wednesday night: IFR likely southern terminals, MVFR northern terminals. E/SE winds 5-10kt. -SHRA or -DZ remain possible. Patchy FG also possible at southern terminals.

Thursday: Some patchy fog early at northern terminals. Generally IFR at southern terminals with MVFR/IFR northern terminals. Rain becoming steady in the afternoon. E winds 10-15 kt with gusts to 20 kt. LLWS possible.

Thursday night: Likely IFR in rain across most terminals. E winds 10-15 kt. LLWS possible.

Friday: MVFR/IFR in rain. Some uncertainty in how quickly rain moves out which will determine how long IFR conditions hold on. E wind 10-15 kt.

MARINE

Winds around 10 kts or less are expected through Tuesday with seas gradually building to 2 to 4 feet beyond 10NM offshore as a SE swell develops with a period of 7 to 8 seconds.

Seas increase to small craft conditions Tuesday night and winds increase to above SCA criteria by Thursday morning on the coastal waters. A 20% chance of gales over the coastal and outer waters late Thursday through Friday.

Sea surface water temperatures range from 38-42F from the Downeast coast out 60NM and east to the Hague Line including Penobscot and Passamaquoddy Bays.

CAR WATCHES/WARNINGS/ADVISORIES

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