textproduct: Caribou

WHAT HAS CHANGED

- 7 AM Update: Reduced forecast sky cover based on current observations and trends in CAMs guidance. Extended small craft advisory as described in marine section. Minor updates to aviation section with the issuance of the 12z TAFs.

- Reduced marine winds and seas slightly based on current observations and continued atmospheric stability in the marine layer

KEY MESSAGES

1) Mild, mainly dry and breezy conditions into Monday may lead to some fire weather concerns.

2) Chance for thunderstorms and warm temperatures Tuesday and Wednesday afternoon.

DISCUSSION

KEY MESSAGE 1...Mild, mainly dry and breezy conditions into Monday may lead to some fire weather concerns.

KEY MESSAGE 1 DESCRIPTION... Behind a recent cold FROPA, high pressure returns to the area for the day today. This subsidence pattern will help clear skies through the day today and dry out the area after recent rain showers. Northwest winds will advect cooler, drier air into the region through the day, particularly across the north. Downsloping into the Downeast region will act to warm this air mass, and temperatures Downeast may lift into the mid 70s while temperatures in the north remain in the mid to upper 60s. The upslope in the north may maintain cloud cover through most of the day today, but once again the subsidence Downeast will help to completely clear skies into this afternoon.

Steep low level lapse rates and an inverted-V presentation on forecast soundings with mixing up to around 850 to 800 mb, along with very dry mid level air, are all ingredients for the potential for rapidly dropping dewpoints this afternoon. Relative humidity in the Bangor and Downeast regions may fall into the low 30 percent range, while northern relative humidity may sit closer to the mid to upper 30 percent range this afternoon. The deep mixing heights will also combine with the tightened pressure gradient aloft behind the recent FROPA and mix these higher winds towards the surface, resulting in wind gusts 25 to 30 mph, and a few gusts to 35 mph possible, particularly in higher terrain. The combination of dry fine fuels, gusty winds, and low RHs may result in some fire weather concerns.

A brief period of frost may develop tonight across the North Woods. For Monday, dry conditions return, with very dry mid levels Monday morning and steep lapse rates to begin the day. A lifting warm front will begin to increase cloud cover from south to north through the day. So though conditions remain similar to the previous day with dry weather and rapidly dropping dewpoints, the decrease in dewpoints and humidity will stall through the afternoon as more moisture returns to the atmospheric profile. Even still, relative humidity could easily fall into the lower 20 percent range through the first half of the day on Monday, though with a relaxed pressure gradient aloft, winds will be relatively light through the day as well.

KEY MESSAGE 2...Chance for thunderstorms and warm temperatures Tuesday and Wednesday afternoon.

KEY MESSAGE 2 DESCRIPTION...

Ridging over the central Atlantic, with mid-level shortwaves moving through Maine. Frontal system moves to the north of the region, with an associated cold front, that potentially becomes stationary to our north on Tuesday. Northern and eastern Maine begins to warm up in the warm sector ahead of the cold front, raising the daytime highs to roughly low 70s up north, and low 80s in the Central Highlands, Bangor, and Downeast regions. Instability rises enduring the afternoon, bringing with it the chance for some thunderstorms across the Central Highlands to Bangor and Downeast regions.

The best chances for thunderstorms on both Tuesday and Wednesday, is during the afternoon into early evening. Potential for roughly 1000 J/kg of CAPE, decent shear parameters, and PWATs roughly around 1-1.5 inches. There could be a change for some gusty winds, given low- level lapse rates rare close to 7-7.5, and DCAPE around 500-700 J/kg. Actual timing of the front is less certain, but generally it seems that it will progress out of the region by Wednesday. Thunderstorms being to dissipate throughout the night Tuesday night and Wednesday night.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

Today: VFR across all terminals with mostly SKC through the day. NW winds 10 to 15 kts with gusts 25 to 30 kts in the afternoon.

Tonight: VFR with developing SKC. Winds light and variable.

Monday: VFR across all terminals, increasing high level cloud cover from south to north through the afternoon. SW winds 5 to 10 kts with gusts to 20 kts around KBGR in the afternoon.

Monday night: VFR with a very small chance of a brief period of MVFR in any developing convection. S winds at 5 - 10kts. LLWS possible.

Tuesday/Tuesday evening: MVFR or lower possible in any stronger thunderstorm, with the best chance in the afternoon/early evening at KCAR/KPQI/KHUL/KBGR. WSW winds G15-20KT possible Tuesday afternoon.

Wednesday: MVFR or lower possible in any stronger thunderstorm. WSW winds G15-20KT possible; becoming NW in the afternoon.

Wednesday night - Thursday: VFR. N/NW winds G15-20KT possible.

MARINE

A small craft advisory now remains in place until 2 PM this morning for seas around 5 ft for the coastal waters. Seas will gradually decrease through the morning, but it is possible this decrease will be slow enough that seas will not fall below advisory levels until this afternoon. A few gusts to 25 kts are possible. Winds should remain below advisory level through tonight and Monday, and seas will gradually diminish to around 2 to 3 ft tonight through Monday.

Winds stay below SCA Monday night, before creeping into Small Craft criteria for the outer waters Tuesday into Wednesday. Chance for rain and some thunder on Wednesday. S winds, becoming SW on Tuesday, turning northwest by Thursday,.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Beach Hazards Statement through this evening for MEZ029-030. MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ050- 051.