textproduct: Caribou

WHAT HAS CHANGED

- 8 PM Update: With smoke aloft streaming in from the north, efficient radiational cooling may become difficult to achieve. Temperatures should still quickly drop, especially with the decrease in winds, however there is room for temperatures to not drop quite as low as originally forecast. Still, the frost advisory remains as there is still a good chance for temperatures to drop low enough for at least patchy frost development.

- A Frost Advisory has been issued in the north for tonight due to increased confidence in cold temperatures.

- A Small Craft Advisory has been issued for coastal and intercoastal waters and a Gale Watch has been issued for outer waters Wednesday night into Thursday due to increased confidence in strong winds over the waters.

KEY MESSAGES

1) Chilly overnight with a chance for frost in the north.

2) Soaking rain is expected areawide Wednesday night.

3) Strong gusty winds expected with the rain Wednesday night and again during the day Thursday.

DISCUSSION

KEY MESSAGE 1...Chilly overnight with a chance for frost in the north.

KEY MESSAGE 1 DESCRIPTION... Cool airmass moves over northern Maine tonight. There is a chance for atmospheric decoupling early in the night, as skies clear out. This will help temperatures to drop into the 30s. Potential for northern areas in Aroostook to drop into the low- to-mid 30s, which will lead to some frost development. Frost chances are going to be highly dependent on the timing of some high level clouds moving in late tonight into early Wednesday morning. If the clouds move in earlier in the night, temperatures will stabilize faster. If clouds move in slower, then there is more time for the temperatures to drop with clear skies. Currently, the set up looks more favorable for decoupling, and thus colder temperatures.

The next chance of frost comes Friday night.

KEY MESSAGE 2...Soaking rain is expected areawide Wednesday night.

KEY MESSAGE 2 DESCRIPTION... A large surface low pressure system in north Canada is expected to bring a strong warm front early Wednesday night and the cold front quickly exiting the region late Wednesday night. Thus, rain should begin early Wednesday evening and taper off around sunrise Thursday. The rain will be occasionally moderate, and cannot rule out an embedded thunderstorm with some instability aloft. As of this update, rainfall totals should reach between 0.5 to 0.75 inches throughout the region. Localized higher totals are possible with heavier convection. Flooding is not a concern with this system, but rain amounts should give some relief to the drought.

As the system exits on Thursday, some wrap around moisture from the system could bring some isolated showers through the north.

KEY MESSAGE 3...Strong gusty winds expected with the rain Wednesday night and again during the day Thursday.

KEY MESSAGE 3 DESCRIPTION... As mentioned above, we are looking at a potent low pressure system passing to the north of the forecast area with strong winds aloft. This will bring strong gusts in the middle of the night Wednesday night from the south, and again during the day Thursday from the west. The winds aloft will be the strongest Wednesday night with up to about 55 kt at 850mb, but it is very unlikely that these winds will reach the ground due to stable low levels that are decoupled from the atmosphere aloft. More realistically, we are looking at gusts as high as about 30 mph from the south Wednesday night in some land areas, with gusts potentially up to 35 mph. Over the waters Wednesday night, a bit of a low level jet develops just offshore, bringing strong gusts, and potentially gales on outer waters. During the day Thursday, though the winds aloft aren't quite as strong, the winds have a much better chance at mixing down to the ground thanks to cold advection aloft with steeper lapse rates, plus the fact that it's daytime. Gusts to about 35 mph from the west appear likely Thursday with the potential for up to 40 mph gusts, and with wet soils after Wednesday night's rain plus leaves on the trees, there could be very isolated tree damage/isolated power outages. Gusts over the waters begin to die down a bit as the low level jet weakens throughout the day Thursday. It remains breezy Thursday night/Friday, though not quite as much as Thursday.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

Tonight - Wed...VFR. Winds light and variable tonight, becoming S 5 to 15 kts Wed.

Wed night...MVFR/IFR with localized LIFR in rain. S winds 10-20 kts with gusts up to 25 kts. LLWS expected.

Thursday...Mainly VFR, with a chance of MVFR north in the morning. Windy with W winds 15-20 kts with gusts to 30 kts.

Thursday Night and Friday...VFR with W winds 10-20 kts, gusting 25-30 kts during the day Friday.

Friday Night and Saturday...VFR with light winds.

Saturday Night and Sunday...VFR with S winds 5-15 kts during the day Sunday.

MARINE

Conditions below Small Craft Advisory levels today through Wednesday. Winds increase quickly Wed night, reaching SCA gusts before midnight for intercoastal and coastal waters. By midnight outer waters should increase to gale force. A Gale Watch has been issued for this area. Seas peak in the range of 5-9 ft late Wednesday night into Thursday morning and then gradually subside. Winds gradually shift to the NW for Friday and become variable and light Saturday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Frost Advisory from 2 AM to 9 AM EDT Wednesday for MEZ001-002- 004. MARINE...Small Craft Advisory from 8 PM Wednesday to 8 PM EDT Thursday for ANZ050>052. Gale Watch from late Wednesday night through Thursday morning for ANZ080-081.