Area Forecast Discussion
Issued by NWS Caribou, ME

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FXUS61 KCAR 041701
AFDCAR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
101 PM EDT SAT JUL 4 2015

.SYNOPSIS...
HIGH PRESSURE MOVES EAST OF THE AREA TODAY. A COLD FRONT MOVES
THROUGH SUNDAY WITH A CHANCE OF SHOWERS AND STORMS. HIGH PRESSURE
RETURNS MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
100 PM UPDATE...WE CONTINUE TO SEE MID AND HIGH CLOUDS STREAM
INTO THE REGION THIS AFTERNOON. THESE CLOUDS ARE LIKELY PRODUCING
SOME RAIN, BUT IT`S DRY ENOUGH AT LOWER LEVELS THAT THIS
PRECIPITATION IS EVAPORATING BEFORE IT REACHES THE GROUND. IN
FACT, YOU HAVE TO GO ALL THE WAY BACK INTO SOUTHERN VERMONT TO
FIND ANY REPORTS OF PRECIPITATION. HAVE THEREFORE KEPT THE DRY
FORECAST FOR THIS AFTERNOON, THOUGH WOULDN`T BE SURPRISED IF
SOMEONE GOT A FEW SPRINKLES, ESPECIALLY IN SOUTHERN AREAS. THE
THICKENING CLOUD COVER AND THE SMOKE FROM WESTERN CANADIAN FIRES
HAVE KEPT THE SUN A BIT MORE AT BAY TODAY, ESPECIALLY ACROSS
NORTHERN MAINE. THIS HAS SLOWED THE TEMPERATURE RISE, SO HAVE
DROPPED EXPECTED HIGHS A FEW DEGREES. OTHERWISE, THE FORECAST IS
IN GOOD SHAPE AND NO OTHER CHANGES WERE NEEDED.

PREVIOUS DISCUSSION... HIGH PRESSURE HAS MOVED OFF TO OUR EAST
WITH LIGHT SOUTH/SOUTHWEST FLOW. HIGH CLOUDS ARE INCREASING LATE
TONIGHT, AND CLOUDS WILL CONTINUE TO INCREASE AND LOWER THROUGH
THE DAY AND INTO TONIGHT. HOWEVER, THIS WILL BE A SLOW PROCESS,
AND TODAY AND THIS EVENING STILL LOOK DRY. THERE MAY BE SOME LIGHT
RAIN FALLING OUT OF CLOUD BASES 10000 TO 15000 FEET THIS AFTERNOON
AND EVENING, BUT A SIGNIFICANT DRY LAYER BELOW SHOULD KEEP THE
RAIN FROM REACHING THE GROUND. BUT DON`T BE SURPRISED IF SOME
LIGHT ECHOES SHOW UP ON RADAR LATER TODAY. HIGHS TODAY WARM AROUND
80.

WEAK COLD FRONT MOVES INTO NW MAINE TONIGHT AND HAVE A SLIGHT
CHANCE OF SHOWERS IN THE FORECAST FOR ABOUT THE NW HALF OF THE
AREA AFTER LATE EVENING IN CASE SOMETHING CAN DEVELOP ALONG THE
FRONT. MOISTURE IS PRETTY LACKING, THOUGH.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
A CONTINUED SPREAD IN THE GUIDANCE AS FAR AS CONVECTIVE POTENTIAL
FOR SUNDAY.

THE COLD FRONT MENTIONED IN THE NEAR TERM IS FORECAST TO SLIDE
ACROSS THE CWA ON SUNDAY. DIFFERENCES STILL REMAIN IN REGARDS TO
DEPTH OF MOISTURE AND TIMING OF THE FRONT. BOTH THE NAM AND TO
SOME EXTENT THE GFS SHOW SB/MUCAPE HITTING 500-1000 JOULES FROM
LATE SUNDAY MORNING THROUGH MID AFTERNOON. PWATS ARE FORECAST TO
AOA 1.00 INCHES W/MODEST 850-500MB LAPSE RATES OF 6-6.5C/KM. A
NOTE ON ALL THIS IS THAT LLVL WARMING IS ON A NW FLOW BEHIND THE
SURFACE FRONT W/LITTLE TO NO CAP. SO, THE BUOYANCY IS THERE.
FACTORS THAT POINT AWAY FROM ORGANIZED CONVECTION ARE LACK OF DEEP
MOISTURE THROUGH 700MBS W/THE MAM MOST AGGRESSIVE W/ITS MOISTURE
WHILE THE GFS IS NOT AS MOIST. BOTH SHOW WEAK SHEAR < 20 KTS
DESPITE THE INVERTED V IN THE LLVLS. THEREFORE, CONFIDENCE ATTM IS
NOT TOO HIGH AND GIVEN THE LACK OF DECENT SHEAR DEPTH OF AVAILABLE
MOISTURE, DECIDED TO STAY W/CHANCE POPS(30-40%) W/THE HIGHEST POPS
AWAY FROM THE COAST. KEPT THE MENTION OF TSTMS BUT LEFT OUT ANY
ENHANCED WORDING ATTM. THE DAYCREW CAN ASSESS THIS FURTHER TODAY
W/LATER GUIDANCE. THE FRONT IS EXPECTED TO CLEAR THE REGION SUNDAY
NIGHT W/HIGH PRES MOVING IN FOR MONDAY AND WARMER.

USED A CONSENSUS APPROACH ON THE QPF W/AREAL BASIN AVERAGES
<0.10". STAYED CLOSE THE DAYCREW`S TEMPERATURES W/UPPER 70S TO
AROUND 80 SUNDAY. UPPER HEIGHTS ARE FORECAST TO RISE ON MONDAY
W/MONDAY HIGH TEMPERATURES HITTING THE 80S.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
DRY AND CONTINUED WARM INTO TUESDAY AND THEN POSSIBLE SHOWERS AND
TSTMS FOR WEDNESDAY W/ANOTHER FRONTAL SYSTEM. DRIER WEATHER
EXPECTED FOR LATE IN THE WEEK.

DIFFERENCES EXIST W/THE LONGER RANGE GUIDANCE ON THE TIMING OF THE
FRONTAL SYSTEM FOR WEDNESDAY INTO WEDNESDAY NIGHT. THE GFS IS
FASTER W/MOVING FRONT OFF THE COAST BY WEDNESDAY NIGHT WHILE THE
ECMWF AND CANADIAN GLOBAL HANG THE FRONT BACK BY ABOUT 6 HRS W/A
WAVE OF LOW PRES RIDING UP ALONG THE FRONT. THESE TWO SOLUTIONS
WOULD KEEP RAIN IN LONGER ALONG THE MAINE COAST THROUGH THURSDAY
MORNING. UPPER FLOW APPEARS TO BE MORE WSW WHICH COULD FAVOR A
SLOWER ENDING TO THE RAINFALL W/THE FRONT BEING HELD UP LONGER.
GIVEN THE UNCERTAINTY THIS FAR OUT AND LOW CONFIDENCE, DECIDED TO
KEEP 20-30% POPS FOR THE DOWNEAST COAST THROUGH THURSDAY AND DRIER
ACROSS THE CENTRAL AND NORTHERN AREAS. FOLLOWED THE CONSENSUS
APPROACH W/TEMPERATURES AS WELL LEANING W/MID TO UPPER 70S INTO
THE LATE WEEK. STILL PLENTY OF TIME TO ASSESS THINGS W/THE LATER
MODEL GUIDANCE.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
NEAR TERM: VFR THROUGH TONIGHT. CLOUDS WILL GRADUALLY THICKEN AND
LOWER THROUGH TODAY AND INTO TONIGHT, BUT EVEN BY LATE TONIGHT,
EXPECT CEILINGS STILL AT VFR LEVELS AROUND 5000 TO 8000 FEET.

SHORT TERM: LOOKS LIKE VFR W/A TEMPO PERIOD OF MVFR FOR SUNDAY
AFTERNOON FOR SHOWERS AND PERHAPS A TSTM. VFR MONDAY RIGHT INTO
TUESDAY.

&&

.MARINE...
NEAR TERM: CONDITIONS EASILY BELOW SMALL CRAFT LEVELS THROUGH
TONIGHT.

SHORT TERM: NO SCA HEADLINES EXPECTED THIS TERM W/WINDS PICKING UP
SLIGHTLY BEHIND THE FRONT SUNDAY EVENING TO 10-15 KTS. A CONTINUED
OFFSHORE FLOW WILL KEEP WAVE HEIGHTS BELOW 5 FT THROUGH THE PERIOD.
DECIDED ON A BLEND OF THE NAM12 AND GFS40 FOR SUSTAINED WINDS
SUNDAY INTO MONDAY AND THEN TOOK A CONSENSUS BLEND MONDAY NIGHT
INTO WEDNESDAY. USED THE LOCAL WAVE MODEL FOR WAVE HEIGHTS FOR
SUNDAY FOLLOWED BY THE WNAWAVE FOR MONDAY THROUGH WEDNESDAY.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...FOISY/HASTINGS
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...FOISY/HASTINGS/HEWITT
MARINE...FOISY/HASTINGS/HEWITT


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