textproduct: Caribou

WHAT HAS CHANGED

- Adjusted the POP timing for the rest of this afternoon with the cold front (FROPA) timing 60-90min faster than previously modeled.

KEY MESSAGES

1) Showers and thunderstorms rest of this afternoon, some of which may be strong with gusty winds and small hail.

2) System bringing rain showers and chance for thunder moves in Sunday afternoon.

DISCUSSION

KEY MESSAGE 1...Showers and thunderstorms today, some of which may be strong with gusty winds and small hail.

KEY MESSAGE 1 DESCRIPTION...

Latest KCBW radar and satellite data shows two areas of showers and thunderstorms. First area of storms are along a cold front that is quickly moving through Northern Aroostook County extending back to Moosehead Lake region. There is a secondary area of storms extending from near Bangor and this is convection developing along and just northwest of the marine layer boundary. Temperatures in the 70s and low 80s between these two boundary is allowing for SBCAPE to be around 1500j/kg, 18z CAR RAOB indicating 2048j/kg of SBCAPE. There is 25-30kt of indicated deep layer shear thanks to recent VWP scans. 18z CAR RAOB confirms this thinking but given how fast this cold front is moving storms are moving too fast to fully organize despite the fairly modest mid-level lapse rates. Cannot rule out a few thunderstorms that make it to severe levels but much of the activity will be sub-severe with gusty winds and perhaps small hail but the FZL is around 13kft.

KEY MESSAGE 2...System bringing rain showers and chance for thunder moves in Sunday afternoon.

KEY MESSAGE 2 DESCRIPTION... Low pressure system in Canada moves eastward this weekend, with trough axis moving through Sunday afternoon. Cold front moves through the state Sunday evening, funneling in some cooler air behind it. Rain moves into the north, generally expanding southeastward during the day Sunday. PWATs generally around 1-1.50 inches based on global and regional model outputs. Global models are keeping precipitation chances pretty modest, around 14 of an inch, while regional models are hinting at some more convective storms developing Sunday evening, bumping up rain totals to one half to three quarters of an inch in isolated locations, predominantly in the north and southeast. Instability parameters include few hundred joules of CAPE, 40-50 kts of effective shear, and some decent low level lapse rates, indicating that a thunderstorm is not out of the question. Heating ahead of the cold front in eastern Maine could aid in initiating some convection along the boundary. Confidence is still low for any severe thunderstorms to develop, given the model disagreement, but regional models are hinting at better instability parameters than earlier indicated.

AVIATION /09Z FRIDAY THROUGH TUESDAY/

Through 00z This Evening...IFR at BHB due to low cigs. VFR at other terms. PROB30 for -TSRA or VCTS with ongoing TStorms. S winds 5-15kt with gusts up to 20kt.

Tonight...IFR/LIFR at BHB due to FG then clears and becomes VFR with FROPA. All other sites VFR FEW cigs or SKC by midnight as skies clear. Light NW winds around 5 kts.

Saturday...VFR under SKC. W winds 5 to 10 kts.

Saturday night...VFR. Chance for valley fog, which would reduce visibility. Light SW winds.

Sunday... MVFR/IFR in afternoon showers and thunderstorms at northern terminals and KBGR. MVFR in showers possible at KBHB. W/SW winds 5 to 10 kts.

Sunday night...MVFR with a chance of rain showers. NW winds at 5 to 10 knots.

Monday...VFR. NW winds at 5 to 10 knots.

Monday night...VFR. Light and variable winds.

Tuesday...VFR. Winds E/SE at 5-10kt.

MARINE

Winds/seas below SCA levels this weekend into early next week. Seas 2 to 4 ft. Fog possible Saturday night. Slight chance for rain showers Sunday night. Winds SW Saturday night into Sunday, and shift W/NW by Monday.

CAR WATCHES/WARNINGS/ADVISORIES

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