textproduct: Caribou

WHAT HAS CHANGED

- 6 AM Update to Aviation section with updates associated with the 12z TAFs

- High Surf Advisory issued for coastal Hancock and Washington counties today.

KEY MESSAGES

1) Rain showers and thunderstorms this afternoon. There is a marginal risk for severe thunderstorms this afternoon and evening. Locally heavy rainfall is possible which could lead to minor urban flooding.

2) Dangerous rip currents and high surf along the Downeast coast today.

3) Potential for a system moving in early next week, bringing another round of wetting rainfall.

DISCUSSION

KEY MESSAGE 1...Rain showers and thunderstorms this afternoon. There is a marginal risk for severe thunderstorms this afternoon and evening. Locally heavy rainfall is possible which could lead to minor urban flooding.

KEY MESSAGE 1 DESCRIPTION... Low pressure system approaches from the west today. Frontal passage is anticipated early this morning as a warm front lifts over the area, leaving northern and eastern Maine in the warm sector of the system. Ample moisture moves in along frontal boundary, with PWATs in the 1-2 inch range. Generally looking at higher rainfall totals along the Downeast coast, with the coast receiving around 1 1.4 inches. Roughly 0.5 1 inches in Central Highlands and northern Maine.

There is a chance for some thunderstorms to move through in the north and Central Highlands/Upper Penobscot Valley regions, as the associated cold front with the system moves through this afternoon into evening. CAMs are picking up on some CAPE, DCAPE, decent shear parameters, low-level lapse rates, and low CIN. Skies will be mostly overcast throughout the area, however, which could cause a damper in convection. North Woods and Aroostook region seems to have the best potential for convection, especially if there is any bit of clearing in the cloud cover. That being said, instability does exist throughout northern and eastern Maine, and any location with some sky clearing and along the front (which will move from west to east during the afternoon), could see some developing storms. There is also a potential for some, albeit light, Canadian wildfire smoke to move in along thew cold front boundary, which would also cause less convection. Greatest threats for these storms will be lightning, heavy rain, and gusty winds. Heavy rainfall could result in localized urban/poor-drainage flooding.

KEY MESSAGE 2...Dangerous rip currents and high surf along the Downeast coast today.

KEY MESSAGE 2 DESCRIPTION... Unusually rough seas by late July standards are expected to peak today. This is usually the quietest time of year on the waters, but seas in the neighborhood of 6-9 feet are expected up to the coastline, with a 9-10 second period swell from the south. People along the coast should exercise caution if recreating. Water temperatures in the 50s.

KEY MESSAGE 3...Potential for a system moving in early next week, bringing another round of wetting rainfall.

KEY MESSAGE 3 DESCRIPTION... A ridge of high pressure will crest over the forecast area this weekend, and during this time temperatures could build to slightly above seasonal averages with highs in the low to mid 80s. By Monday next week, another shortwave may approach from the west, bringing the next round of moisture into the area that could charge the atmosphere for more rainfall across the CWA. Recent guidance suggests the bulk of the instability with this system will hold off until Tuesday at the earliest, where more CAPE could lead to the development of some thunderstorms. More moisture on Tuesday may also support more efficient rain processes.

AVIATION /09Z WEDNESDAY THROUGH SUNDAY/

Today...MVFR/IFR in low cigs from rain showers. Winds generally S/SE, at 10 to 15 kts. Chance of thunderstorms this afternoon north of coastal terminals. Expecting seabreeze to keep KBHB out of convection. Thunderstorms could reduce visibility and have gusty winds and heavy rainfall.

Tonight...Rain and thunderstorms dissipate by dusk, and then VFR conditions. SW winds in the north, and W winds Downeast, at 5 to 10 kts.

Thursday...VFR conditions. W winds at 10 to 15 kts.

Friday - Sunday...VFR conditions continue across all terminals. SW winds shifting S 5 to 10 kts through the weekend, becoming light and variable each night.

MARINE

Small Craft Advisory conditions over intra-coastals and coastal waters today into tonight. Wave heights reach their peak tonight, roughly 6-9 ft. High Surf Advisory along the coastline, due to elevated rip risk and rough seas. Some fog and rain showers early this morning. Chance for some fog on eastern waters Thursday morning. S winds today, shifting W by Thursday.

Winds and seas decrease below small craft advisory conditions across all waters Friday through the weekend.

CAR WATCHES/WARNINGS/ADVISORIES

ME...High Surf Advisory until 8 PM EDT this evening for MEZ029-030. MARINE...Small Craft Advisory until 6 AM EDT Thursday for ANZ050>052.