textproduct: Caribou

WHAT HAS CHANGED

Updated Aviation Section for 6Z TAF.

Increased confidence in marginal risk for severe thunderstorms Wednesday afternoon/evening.

KEY MESSAGES

1) Wetting rain is expected areawide Tuesday night into Wednesday night. There is marginal risk for severe thunderstorms, Wednesday afternoon and evening. Locally heavy rainfall is possible leading to minor urban flooding.

2) Dangerous Rip Currents and potentially High Surf along the Downeast coast Wednesday

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

DISCUSSION

KEY MESSAGE 1... Wetting rain is expected areawide tonight into Wednesday night. There is marginal risk for severe thunderstorms, Wednesday afternoon and evening. Locally heavy rainfall is possible leading to minor urban flooding.

KEY MESSAGE 1 DESCRIPTION... A full latitude trough remains over the eastern U.S. from tonight into Wednesday evening, with shortwaves embedded in the southwest flow aloft over the region. At the surface, a warm front lifts north into Maine tonight and lifts to the north Wednesday morning, followed by a cold front that crosses Maine Wednesday afternoon and evening.

Warm advection rain showers develops from SW to NE this evening. There is also a chance of thunder tonight, mainly south of a Houlton to Katahdin line. The latter is in response to forcing from a 50-55KT low level jet crossing Downeast Maine Tuesday night. Any thunder should be elevated in nature with no CAPE, but Showalter indices around 1-3C supporting isolated- scattered elevated storms. This will also result in the heaviest rainfall tonight over Downeast Maine as well.

There should be a lull in the precipitation at some point Wednesday morning, once the warm front finishes lifting through, then showers and thunderstorms should develop over far NW zones Wednesday afternoon, then press ESE across the region into Wednesday evening. The region should be in the left front quadrant of a 100+ kt upper level jet, in addition to support from a 50-55KT low level jet near the coast. With 1000-2000 J/kg of CAPE, 35-50KT of bulk shear (strongest over Downeast Maine), along with 1000-1500 J/kg of Downdraft CAPE, there is the potential for strong to severe thunderstorms Wednesday afternoon and evening. Accordingly SPC has the region under a Marginal Risk for Severe Thunderstorms during this time.

In addition should see 3/4" to 1 1/3" of rain across the Bangor Region and Downeast Maine, with 1/3" to 3/4" elsewhere. Given Precipitable Waters Wednesday afternoon/evening of 1.5 to 1.75" along with the aforementioned jet support, there is the potential for locally heavy rainfall, which could result in locally higher amounts. With the best forcing over Downeast Maine/the Bangor Region, the best chance for any localized flooding of urban/known poor drainage areas is in that region.

KEY MESSAGE 2... Dangerous Rip Currents and potentially High Surf along the Downeast coast Wednesday.

KEY MESSAGE 2 DESCRIPTION... Persistent onshore flow and a strengthening southerly swell will build seas near shore to 6-9ft from Wednesday into Wednesday night. The resulting rough surf and dangerous rip currents will make going to area Atlantic/Gulf of Maine Beaches Hazardous. There is some uncertainty as to exactly how strong the swell will be and the timing of its arrival, so do not quite have the confidence to issue a High Surf Advisory or a Rip Current Statement at this time.

Situations like this have resulted in people being swept into the ocean by larger waves crashing on the cliffs at Acadia.

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

KEY MESSAGE 3 DESCRIPTION... High pressure lingers over the region this weekend, as low pressure system slides along the east coast late weekend into early next week. Exact track of the low pressure system is uncertain, but generally, models agree that it will move over the Gulf of Maine. To the north, another low pressure over Canada moves towards the region as well. Wetting rainfall is possible, and there could be some thunder potential along the passing cold front.

AVIATION /06Z TUESDAY THROUGH SATURDAY/

High confidence in VFR conditions through 00Z Wednesday. Conditions should then deteriorate to MVFR or lower this evening, with the highest confidence in the lowest conditions at KBHB, which could see VLIFR.

Light and variable winds to start the TAF period, become SSE-S at 10KT or less around 12Z, then become gusty out of the S-SSE at 10-15G20-25KT by mid morning. Winds back to the SE this evening, with most terminals (except for possibly KFVE and KHUL) losing there gusts with speeds settling around 10KT. LLWS develops at all terminals around midnight.

Late tonight-Wednesday...IFR or lower likely. Strong to possibly severe thunderstorms possible Wednesday afternoon/evening. LLWS likely at southern terminals and possible at northern terminals. S-SSE winds G15-20KT possible Wednesday at northern terminals.

Wednesday night...MVFR/IFR in low clouds and fog. Lingering rain at KBHB possible. S winds at 5-10 kts, shifting W overnight.

Thursday - Saturday...Mainly VFR. W/SW wind at 5-10 kts.

MARINE

Winds less than 15 kt and seas 4 ft or less early this morning, gives way to SCA conditions on the coastal ocean waters this afternoon, with gusts to 25 kt on the outer waters as well. SCA conditions then develop on the intra-coastal waters by this evening. SCA conditions then continue on the coastal waters through Wednesday, with gusts up to 30 kt on the outer waters. There is a low chance for gusts to gale force on the outer waters on Wednesday, but currently confidence in this is not high enough to reflect in the forecast.

Strong to possibly severe thunderstorms are possible over the waters Wednesday afternoon and night.

SCA conditions persist Wednesday night, until winds relax Thursday morning, and wave heights fall below SCA criteria by Friday. Seas peak Wednesday night, around 6-9 ft over intra- coastals, and 9-11 ft for all outer waters. Fog over the waters Wednesday night into Thursday morning. Some lingering rain showers Wednesday night. S winds Wednesday night, becoming SW on Thursday. Winds shift W/NW Friday.

CAR WATCHES/WARNINGS/ADVISORIES

ME...None. MARINE...Small Craft Advisory from noon EDT today until 6 PM EDT Wednesday for ANZ050-051. Small Craft Advisory from 6 PM EDT this evening to 6 PM EDT Wednesday for ANZ052.