textproduct: Caribou

WHAT HAS CHANGED

- Increased confidence in low temperatures falling into the 30s overnight tonight across Penobscot County and north. Have issued a Frost Advisory for southern Penobscot County from midnight tonight through 7 AM Thursday.

- Increased confidence in impacts Downeast from the coastal low.

KEY MESSAGES

1) Potential for frost tonight inland from the coast and north.

2) A coastal low will impact at least Downeast Maine late this week.

DISCUSSION

KEY MESSAGE 1...Potential for frost tonight inland from the coast and north.

KEY MESSAGE 1 DESCRIPTION... Surface 1040mb high pressure is centered over Quebec this afternoon, with upper level high pressure building into the region from Ontario. This pattern will continue tonight, resulting in clear skies and light winds, similar to last night. Once again this should result in a cold night, frost, and river valley fog. A modifying air mass could limit how low temperatures fall tonight, but lows in the 30s are expected outside the Downeast Coast. Northern areas of Maine will likely reach freezing or below freezing. A Frost Advisory is in effect for southern Penobscot County from midnight tonight to 7 AM Thursday. While not as cold as tonight, Thursday night could see additional patchy frost and fog, mainly in northern areas as clouds increase from the south.

KEY MESSAGE 2...A coastal low will impact at least Downeast Maine late this week.

KEY MESSAGE 2 DESCRIPTION... A coastal low is expected to develop across the Mid-Atlantic region late this week while high pressure remains centered over Quebec. The timing and track of the ocean low is still uncertain with blocking high pressure to the northwest of our forecast area and ridging across the Great Lakes. Latest ECMWF guidance delays the onset of rain into the weekend as the blocking high remains resolute over Eastern Canada. This will result in additional uncertainty in how close the low will pass to the coast which will determine how far north the precipitation will reach. Regardless, northerly to northeasterly winds will become gusty over the weekend, especially along the coast, as a tight pressure gradient forms. General trend currently is that the low pressure system will continue to move southwards due to the high pressure, with majority of the rain staying over the waters and the Downeast region.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

Today-Thursday...VFR, though may see patchy fog occasionally restrict visibilities again tonight. NNE winds 5 kts.

Thursday night...Variable conditions in any patchy late night fog, otherwise VFR. North/northeast winds 5 to 10 knots.

Friday - Monday...VFR north. VFR/MVFR Downeast with likely rain. Across northern areas, N/NE winds 5 to 10 knots, becoming NE Sunday. Across Downeast areas, N/NE winds 10 to 15 knots with gusts up to around 20-25 knots at KBGR, and 30 knots possible at KBHB Saturday and Sunday afternoon. Winds diminish Sunday night back to 10 to 15 knots.

MARINE

NE wind gusts increase to 25-30kts over the outer waters this afternoon. Winds diminish after this time through Thursday. Seas range from 3-5 feet over the outer waters through the end of the period, with seas from 2-3 feet over the intracoastal and coastal ocean waters before slowly increasing Thursday afternoon.

Northeast winds and seas increase to gales late Thursday night into Friday, winds peaking around 45 knots in the outer waters and around 40 knots in the coastal waters by Friday night. A gale watch is now in effect from 8AM on Friday in outer waters and from 5PM in coastal waters and will persist through at least 8PM Sunday night. Gales remain possible in the intracoastal waters. Peak wave heights in the outer waters will be around 11ft to 16ft, and around 7ft to 12ft in the coastal waters.

CAR WATCHES/WARNINGS/ADVISORIES

ME...Frost Advisory from midnight tonight to 7 AM EDT Thursday for MEZ015. MARINE...Gale Watch from Friday afternoon through Sunday evening for ANZ050-051. Gale Watch from Friday morning through Sunday evening for ANZ080-081.