textproduct: Caribou

SYNOPSIS

An upper level trough will remain across the region early week while surface high pressure gradually builds south across Quebec through midweek. Low pressure will then approach from the south late week and cross the area next weekend.

NEAR TERM /THROUGH MONDAY NIGHT/

745 PM Update: Scattered rain showers continue to wrap around the trough of low pressure centered east of the forecast area, with light rain falling over most of the CWA. The chance for rain showers will persist through the night as the low is slow to exit the region. Slight adjustments made to the timing of the precip exit and temperatures based on current observations and trends, otherwise the previous forecast remains on track.

Previous Discussion: 500mb shortwave energy and vort max creating scattered showers this afternoon will slowly pivot S and SE tonight. We will remain under the influence of the cold pool aloft tonight. Expecting isolated to scattered rain showers to continue overnight. Freezing levels will once again drop to 1500-2000ft bringing some mixing of snowflakes within the rain across portions of the North Woods with snow showers likely on the higher elevations like Katahdin. Katahdin will likely see an inch or so of snowfall through tomorrow morning combined with rime icing. Elsewhere tonight, generally a trace to a few hundreths of an inch of rainfall. Temperatures will be falling back into the mid to upper 30s but cannot rule out temps getting stuck around 40F in spots. Light NNW winds shifting slightly N tonight across the area less than 10mph with widespread cloud cover.

On Monday, the 549dam 500mb low will drift east over Nova Scotia with continued Maritime air over the area with upper level winds out of the NE. Isolated to scattered showers will be possible all day but this time given the low position to our east much of the activity will be along and east of I95. Light N winds and mostly cloudy skies will result in highs in the mid to upper 40s north with upper 40s to around 50F south.

Monday night a 1035mb surface high over Central Quebec slowly drifts SE and starts to control our weather. This is a very slow process right now with negative NAO blocking in the North Atlantic. The 500mb low will drift just south of Nova Scotia with showers mainly confined to the Downeast coast and the Passamaquoddy Bay region. Light N winds continue with partly to mostly cloudy skies. Latest trends in the NBM along with other model guidance showing increasing probabilities of 20s in the North Woods thanks to winds decoupling. Will go with mid to upper 20s west of Route 11 in the North Woods including Masardis to Ashland area. Elsewhere across the north expecting low to mid 30s then mid to upper 30s for the Central Highlands to Downeast coast.

SHORT TERM /TUESDAY THROUGH WEDNESDAY/

On Tuesday, the upper level low will shift eastward and high pressure will fill in behind it. The surface low will already have shifted further eastward, and stability will increase through the day. A lingering northeasterly wind along the coast will form a weak barrier jet, bringing gusty winds to the coastal waters. Otherwise, skies will clear and calm weather will dominate through Wednesday. Atmospheric decoupling overnight, combined with a colder air column aloft will cool surface temperatures Tuesday night and overnight lows will drop into the mid-20s for the northern portion of the forecast area, with the Downeast area only falling into the mid-30s.

LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/

Wednesday night, the uncertainty begins with the next system expected to affect the Northeast through the end of the week. While models are in general agreement that there will be a low pressure system moving up the east coast that has the potential to tap into the tropical moisture fueling Melissa, the timing, strength, and low track are all highly variable at the moment. Part of the variability is due to uncertainty about how long the high pressure system will hang on, pushing the low to the south. Current deterministic runs of the GFS and Canadian have the occluded front entering Maine early Friday morning. However, ensembles have the precip onset timing varying from Thursday evening through early Sunday morning. It seems mostly likely that the front will be delayed a little bit from previous runs, as this has been the overall trend. Due to this uncertainty, the current forecast has precip starting Thursday night, but model mean timing shows that precip will move into the Bangor area closer to Friday morning. Although all models have the front moving relatively quickly, the timing of precip onset is pretty key in terms of determining whether it will be a wet and somewhat windy Halloween night. At this point, it is best to prepare for a wet evening Friday evening. Although this system will be linked offshore to the remnants of Melissa, the rapid movement will limit the amount of precip over northern Maine. Therefore, expect this system to deliver some improvement to soil moisture, but not nearly enough to end the drought.

Heading into the weekend, another low pressure system is on the horizon, possibly approaching as early as Sunday evening. However, given the uncertainty on the first system, details are not being resolved at this time and will have to see how the previous days play out.

AVIATION /00Z MONDAY THROUGH FRIDAY/

NEAR TERM: Tonight: MVFR cigs with a few northern sites approaching IFR, low confidence in IFR cigs. Scattered rain showers through tonight all terms. N winds tonight 5 to 10 kts.

Mon - Mon night: MVFR cigs all terms and scattered showers decreasing through the day. N winds 5 to 10 kts.

SHORT TERM: Tuesday through Wednesday...Mostly VFR. Some limited chance for fog Tuesday night, but unlikely to severely affect any terminal sites. North/northeast winds 10 to 15 knots with gusts up to 20 knots Tuesday, 5 to 10 knots Tuesday night, then around 10 knots Wednesday.

Wednesday night and Thursday...VFR. Variable winds 5 to 10 knots.

Thursday night...Mainly VFR. Chance of rain developing Thurs evening into Friday morning. Variable winds 5 to 10 knots. Timing on rain development and potential lowering of ceilings highly uncertain at this point.

Friday...MVFR/IFR in rain. E winds 10 to 15 kts with possible gusts to 25kt along the front.

MARINE

NEAR TERM: Winds/seas below SCA conditions through Monday evening. NNW winds this evening shift N overnight generally less than 15kt. N winds Monday night after midnight will increase and begin gusting near 25kt over the outer portions of the coastal waters and east to the Hague Line. In terms of seas expecting 1-2ft tonight into Monday afternoon building to 2-4ft Monday night. Sea surface water temperatures are in the 51-54F range from the Downeast coast out 25nm and east to the Hague Line including Penobscot and Passamaquoddy Bays.

SHORT TERM: Small craft winds expected to continue, mainly over the outer waters Tuesday through Wednesday morning. A brief break in windy conditions through Thursday morning, with winds increasing above 25kts again late Thursday night. Possible gales on Friday ahead of the main front. Seas during this period generally 3 to 5 feet, increasing to 5 to 8 feet during the day on Friday.

CAR WATCHES/WARNINGS/ADVISORIES

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