textproduct: Caribou

WHAT HAS CHANGED

- Updated aviation section to reflect 12z TAFs

- Increasing confidence in above normal temperatures early next week which could challenge daily record highs, and increased confidence in significant snow pack reduction in this pattern

KEY MESSAGES

1) Light Freezing rain or drizzle will impact the region early this morning followed by rain and warmer temperatures this afternoon.

2) Temperatures remain above normal through Tuesday, leading to significant snow melt and rotting of river and lake ice.

3) Low pressure moving through the region Wednesday into Thursday could bring snow, rain, or even a wintry mix to the forecast area.

DISCUSSION

KEY MESSAGE 1... Light Freezing rain or drizzle will impact the region early this morning followed by rain and warmer temperatures this afternoon.

KEY MESSAGE 1 DESCRIPTION... Moisture will continue to increase across the region early this morning in advance of an approaching warm front. Expect a period of freezing rain or drizzle through mid morning. This may result in locally slick travel conditions on untreated road surfaces. The precipitation will change to all rain by mid morning across the greater Bangor region and central areas, and by mid day across the colder valleys of far northern Maine. Any ice accumulations will generally be a tenth of an inch or less. Temperatures by late afternoon will rise into the upper 30s to around 40 north and and the lower 40s for the Bangor region and Downeast areas. Temperatures will remain well above normal levels on Sunday. This will result in increased snowmelt.

KEY MESSAGE 2... Temperatures remain above normal through Tuesday, leading to significant snow melt and rotting of river and lake ice.

KEY MESSAGE 2 DESCRIPTION... A mild air mass remains in place over the forecast area through the first half of the upcoming week. With ridging in place over the area, there are not expected to be any disturbances to shift air masses, allowing for the mild air mass to remain over northern New England for several days while temperatures gradually rise into the middle of the week, reaching 2 to 3 standard deviations above normal. This rise in temperature could lead to high temperatures lifting into the low to mid 50s through the CWA, and low temperatures each night falling into the upper 20s to mid 30s. More information on temperatures with respect to climate norms can be found in the Climate section below.

These abnormally warm temperatures will significantly erode the existing snow pack. Current calculations through Monday night suggest 1 to 2 inches of SWE loss. Currently SWEs across the forecast area sit around 2 to 4 inches. While the northern half of the forecast area will be slowest to respond to this heat wave with current snow temperatures in the teens and greatest starting snow depth, Downeast snow pack could be reduced by at least half, though it is becoming increasingly likely that the snow pack Downeast could be completely wiped out under this warm weather. These warm temperatures will support river and lake ice rot as well.

KEY MESSAGE 3... Low pressure moving through the region Wednesday into Thursday could bring snow, rain, or even a wintry mix to the forecast area.

KEY MESSAGE 3 DESCRIPTION... A low pressure system will approach the area from the west through the middle of the week. There remains a variety of solutions with this system.

Where there is good agreement: - An open wave surface low pressure system will move into the area. At least a portion of the forecast area will spend some time within the warm sector of this system. - Temperatures will drop behind the low pressure passage as a more seasonable air mass returns for the end of the week. - There is relatively high confidence that at least a portion of the forecast area will see measurable precipitation through the middle of the week.

What remains most unknown: - The exact path the surface low will take. If the low crosses further north, more of the forecast area will become encompassed by the warm sector and precip types will lean more towards rain, or even a dry slot with lower precip amounts. The ECMWF deterministic is a good example of the warm solution. If the low tracks closer to the coast, colder air will rush in more quickly, with snow being a more likely precip type for a larger portion of the CWA. With dry slot potentially remaining off-shore, this solution could yield higher precip amounts as well. The GFS deterministic is an example of this solution. By examining the NBM, ICON, and UKMET guidance, the warmer solution seems to be the more likely solution at this time, with lesser QPF and more rain, but confidence remains quite low, and so the NBM solution with rain/snow mix was left in this current forecast. - The existence of any wintry mix is also unknown at this time. Several forecast soundings indicate a warm nose will accompany onset of precip with this system, which could lead to freezing rain and/or sleet across the region. Even guidance which maintains a more clear rain/snow solution, such as the GFS, has a warm nose signature, albeit higher in the profile.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Widespread IFR/LIFR conditions are expected at all the terminals through tonight in low ceilings and patchy fog. -FZDZ/-FZRA will impact the terminals early this morning followed by -RA this afternoon into tonight. MVFR/IFR conditions expected Sunday morning with conditions improving to VFR during Sunday afternoon. Low Level Wind Shear is expected to affect the terminals through tonight. Expect surface winds S 10 to 20 kt with G25kt today, then S around 10 kt tonight. SW wind 10 to 15 kt on Sunday.

Sun night - Mon...VFR across all terminals. SW winds 5 to 10 kts shifting S at 10 to 15 kts with gusts to 25 kts.

Mon night - Tue...VFR across all terminals with SKC spreading throughout the region. SW winds shift W 5 to 10 kts.

Tues night...VFR early, possibly decreasing towards IFR late as precipitation approaches. N winds around 5 kts.

Wed...MVFR/IFR probable Wed morning, depending on storm track. Low cigs likely to be accompanied by precipitation, but remains unknown at this time if that will be rain, snow, or a wintry mix as precip type will be highly dependent on exact low track. Chance of IFR/LIFR cigs increases by Wed night. NE winds 5 to 10 kts with gusts to 20 kts possible.

MARINE

Winds and seas will gradually increase later today into tonight. Have issued a Gale Warning for the outerwaters late this afternoon through early Sunday morning, and a small craft advisory for the intra coastal zone this afternoon through Sunday afternoon.

Marginal small craft advisory criteria could be met to begin next week with seas around 5 ft and gusts 25 to 30 kts, highest gusts occurring overnight Monday night. Warm temperatures will limit any threat of freezing spray. Seas will increase on a southerly swell Monday night into Tuesday, becoming 4 to 6 ft across all marine zones. SCA criteria may return once more on Wednesday as the next storm system rolls into the area.

CLIMATE

Abnormally warm temperatures will lead to daily highs approaching record daily high temperatures through the beginning of the week.

Monday, March 9:

Caribou: Forecast 49 F; Record 47 F set in 1998 Houlton: Forecast 52 F; Record 53 F set in 2012 Millinocket: Forecast 54 F; Record 57 F set in 2016 Bangor: Forecast 55 F; Record 59 F set in 2016

Tuesday, March 10

Caribou: Forecast 44 F; Record 55 F set in 1977 Houlton: Forecast 51 F; Record 58 F set in 1977 Millinocket: Forecast 54 F; Record 54 F set in 2016 Bangor: Forecast 57 F; Record 62 F set in 1977

CAR WATCHES/WARNINGS/ADVISORIES

ME...Winter Weather Advisory until 1 PM EST this afternoon for MEZ001>006-010-011-015>017-031-032. MARINE...Gale Warning from 3 PM this afternoon to 8 AM EST Sunday for ANZ050-051. Small Craft Advisory from 1 PM this afternoon to 4 PM EST Sunday for ANZ052.