Area Forecast Discussion Issued by NWS Caribou, ME
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000
FXUS61 KCAR 250839
AFDCAR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
439 AM EDT SAT MAY 25 2013
.SYNOPSIS...
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AN AREA OF LOW PRESSURE WILL SLOWLY MOVE NORTHEAST ALONG THE
SURFACE BOUNDARY DRAPED ACROSS EASTERN MAINE TODAY INTO SUNDAY.
ANOTHER ROUND OF RAIN CAN BE EXPECTED INTO SUNDAY.-- End Changed Discussion --
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.NEAR TERM /UNTIL 6 PM THIS EVENING/...
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CHALLENGE WILL BE RAFL AMOUNTS AND TEMPERATURES TONIGHT.
06Z SFC ANALYSIS HAD THE SFC FRONT LOCATED ACROSS THE EASTERN SIDE
OF ME W/LOW PRES SLOWLY MOVING N FROM SE MA. LATEST RADAR TREND
SHOWED RAFL W/1 AREA MOVING ACROSS NORTHERN MAINE(EAGLE LAKE INTO
FORT KENT) AND THE 2ND AREA WAS MOVING NORTH THROUGH WESTERN
AREAS THAT ALREADY RECEIVED A GOOD DOSE OF RAFL ON FRIDAY.
ENHANCED ECHOES ON THE RADAR INDICATED HEAVY RAFL AND ENHANCED
CLOUDS ON THE SATL IR SUPPORT THIS AS WELL. THE NAM(00Z) AND ITS
COUNTERPART THE NAM12 HAD THESE AREAS MAPPED OUT QUITE WELL AS DID
THE 00Z GFS. EVEN THE 12Z ECMWF WAS IN LINE BUT DUE TO ITS
COARSENESS, KEPT THE AREA MORE BROAD. DECIDED ON THE NAM/NAM12
WHICH SHOWED THE FIRST SLUG OF RAFL LIFTING OUT AND A RESPITE FOR
A TIME BEFORE THE NEXT SLUG OF SIGNIFICANT RAFL HEADS N LATER
TODAY INTO TONIGHT W/THE SFC LOW LIFTING UP FROM THE S. QPF WAS
ADJUSTED USING THE GFS/NAM12/HPC WHICH SHOWS 2 AREAS OF HEAVIER
QPF W/ONE AREA ON THE WESTERN SIDE AND ANOTHER ALONG THE ME-NB
BORDER AS DEFORMATION BANDING AND STRONG MID LEVEL FORCING SETS
UP. PLUS, SFC & UPPER LEVEL FRONT WILL ADD TO LIFT/CONVERGENCE
WHICH IN TURN WILL ENHANCE THE RAFL, HEAVY ATIM TIMES IN THE
AFOREMENTIONED AREAS. THE GROUND IS ALREADY SATURATED AND
ADDITIONAL(HEAVIER RAFL) WILL LEAD TO RUNOFF INTO STREAMS AND
RIVERS. THIS IS ADDRESSED FURTHER IN THE HYDROLOGY SECTION BELOW.
TEMPERATURES WILL NOT RISE MUCH FROM WHERE THEY ARE W/THE
EXCEPTION OF THE EASTERN 3RD OF MAINE AS WAA AT 925-850MBS COULD
ALLOW FOR TEMPERATURES TO HIT ABV 50F. OTHERWISE, 40S WILL BE THE
RULE TODAY AND THE NNE WIND WILL MAKE IT FEEL MORE LIKE FALL THAN
LATE SPRING.
FOR TONIGHT, LOW PRES SLOWLY LIFTS N AS IT GETS CAPTURED UNDER THE
UPPER LOW. AS MENTIONED ABOVE, RAFL TO CONTINUE THROUGH THE NIGHT
AND WILL BE HEAVY AT TIMES. FOLLOWED A GFS/NAM12/SERF BLEND FOR
THE POPS WHICH SHOWS 100% THROUGH MIDNIGHT AND THEN THE AREA OF
STEADY/STRATIFORM RAFL LIFTS N WHILE CENTRAL AND DOWNEAST AREAS
GET UNDER A MORE SHOWERY REGIME. STAYED W/THE BLEND MENTIONED
ABOVE FOR QPF WHICH SHOWED AN ADDITIONAL 0.50-1.00 INCHES OF RAFL
FROM 12Z. POCKETS OF HEAVIER AMOUNTS ARE POSSIBLE ESPECIALLY IN
THE UPSLOPE FAVORED AREAS OF SOMERSET AND PISCATAQUIS COUNTIES AND
EASTERN WASHINGTON AND SE AROOSTOOK COUNTIES. TEMPERATURES WILL
FALL BACK AFTER MIDNIGHT AND COULD DROP INTO THE MID 30S BACK
ACROSS THE ME-QUEBEC BORDER. 925MBS TEMPERATURES FROM THE ECMWF
ARE FCST TO DROP TO -1C WHICH COULD ALLOW FOR SOME WET SNOW.
DECISION WAS TO CARRY A MIX OF RAIN/SNOW BY EARLY SUNDAY MORNING
NEAR THE WESTERN/NWRN ME BORDER.-- End Changed Discussion --
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.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
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LOW PRESSURE IN THE GULF OF MAINE AT THE BEGINNING OF THIS PERIOD
WILL MOVE NORTH INTO THE MARITIMES MONAY. EXPECT RAIN SUNDAY
GIVING WAY TO SHOWERS AS THE SURFACE LOW MOVES TO THE NORTH.
FORECAST AREA REMAINS UNDER STRONG UPPER LOW INTO MONDAY. FOR POPS
AND QPF HAVE BLENDED THE NAM12...GFS40...SREF...GEM AND ECMWF.
WILL MAKE SOME MINOR MANUAL ADJUSTMENTS TO POP GRIDS TO INCREASE
HIGHEST POP NUMBERS. FOR WINDS HAVE USED A 50/50 BLEND OF THE
NAM12 AND GMOS. TEMPERATURE GRIDS GENERATED WITH BIAS CORRECTED
NAM. FOR DEWPOINT USED GEM.-- End Changed Discussion --
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.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
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HIGH PRESSURE BUILDS IN FROM THE WEST AND DOMINATES AT THE
BEGINNING OF THIS PERIOD. A WARM FRONT IS EXPECTED TO APPROACH
FROM THE SOUTHWEST TUESDAY NIGHT. LOW PRESSURE PASSES TO THE NORTH
OF THE STATE WEDNESDAY NIGHT THEN BECOMES STATIONARY OVER THE
NORTHERN PORTION OF THE STATE THURSDAY. HAVE INITIALIZED ALL GRIDS
WITH GMOS. WILL ADJUST POPS AND SKY COVER. ALSO WILL ADJUST
TEMPRATURE TO BETTER FIT THREE HOUR MOS TEMPERATURE.-- End Changed Discussion --
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.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
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NEAR TERM: MVFR ACROSS THE FAR NORTHERN TAF SITES THIS MORNING(N
OF KHUL), FROM KHUL ON S TO KBHB, IFR CONTINUING TODAY W/A BRIEF
PERIOD OF MVFR LATER THIS MORNING. TONIGHT, ALL TAF SITES WILL
DROP BACK TO IFR W/THE NEXT ROUND OF RAIN.
SHORT TERM: EXPECT IFR CONDITIONS SUNDAY. VFR CONDITIONS EXPECTED
MONDAY AND TUESDAY. MVFR CONDITIONS POSSIBLE WEDNESDAY.-- End Changed Discussion --
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.MARINE...
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NEAR TERM: SCA EXTENDED INTO SUNDAY. COULD SEE GUSTS HIT 25 KTS
TODAY W/SURGE OF LLVL JET AT 850MBS(35KTS), BUT IT LOOKS AS THOUGH
THE HEADLINE CAN BE TRANSITIONED OVER TO A SCA FOR HAZARDOUS SEAS
TODAY BY THE DAYCREW. USED THE NAMSWAN FOR WAVE HEIGHTS GOING TO 7
FT LATER TODAY AND THEN DROPPING OFF LATER TONIGHT. THE NAMSWAN
WAS WAS DOING QUITE WELL THIS MORNING PER 06Z OB. NAM12/GFS BLEND
WAS USED FOR THE WINDS WHICH KEEP SUSTAINED WINDS 15-20 KTS INTO
THIS EVENING. STAYED CLOSE TO THE DAYCREW`S ASSESSMENT OF GUSTS TO
25 KTS.
SHORT TERM: FOR SUSTAINED WINDS WILL INITIALIZE GRIDS WITH A
50/50 BLEND OF THE NAM12 AND GFS40. WILL USE 125 PERCENT OF
SUSTAINED WINDS FOR GUST SPEED. WILL ALSO LOWER SUSTAINED WIND
SPEED FEW KNOTS DUE TO SEA SURFACE TEMPERATURE INTO SUNDAY. FOR
WAVES: LONG FETCH DEVELOPS FROM THE GULF OF MAINE SOUTHWARD PRIOR
TO THIS FORECAST PERIOD. THIS WILL RESULT IN LONG PERIOD WAVES
ARRIVING FROM THE SOUTHEAST FOR SEVERAL DAYS. SPECTRAL DATA FROM
WNA INDICATES SOUTHERLY WAVE SYSTEM PRIMARY WAVE GROUP (AT 9 TO 10
SECONDS) THROUGH MONDAY. WILL GENERATE WAVES WITH NAM/SWAN THROUGH
1200Z MONDAY THEN TRANSITION TO WNA/4. EXPECT LONG PERIOD WAVE
FIELD TO FALL BELOW 5 FEET MONDAY MORNING...HOWEVER SOUTHERLY
SWELL WILL PERSIST INTO TUESDAY.-- End Changed Discussion --
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.HYDROLOGY...
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SOME CONCERN FOR THE WESTERN AREAS SUCH AS NORTHERN SOMERSET AND
PISCATAQUIS COUNTY AND ALSO FOR THE EASTERN SIDE OF MAINE LIKE SE
AROOSTOOK AND WASHINGTON COUNTY. ADDITIONAL HEAVY RAFL COULD LEAD
TO SOME MINOR ISSUED MAINLY LOWLANDS. PONDING OF WATER WILL BE
MAIN CONCERN. THESE AREAS HAVE ALREADY SEEN 1-2+ INCHES OVER THE
LAST 36 HRS AND AN ADDITIONAL INCH OF RAFL COULD OCCUR. THE
MAINSTEM RIVERS LOOK LIKE THEY WILL HANDLE THE RAFL FOR THE MOST
PART. BIG BLACK RIVER IN WESTERN AROOSTOOK AND THE PISCATAQUIS
RIVER BASIN WILL NEED TO BE MONITORED TODAY AS WILL THE ST. CROIX
RIVER AND SOME OF THE SMALLER RIVERS/STREAMS IN WASHINGTON COUNTY.
THESE WATERSHEDS HISTORICALLY CAN FILL UP FAST.-- End Changed Discussion --
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.TIDES/COASTAL FLOODING...
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A COASTAL FLOOD ADVISORY IS UP FOR HANCOCK COUNTY. HIGH TIDE IS
AT 1530Z THIS MORNING AND THE TIDE IS EXPECTED TO BE 11.77 FT. A
SURGE OF 0.5 FT IS EXPECTED. MINOR OVERWASH EXPECTED MAINLY ALONG
SEAWALL ROAD. THERE IS A CONCERN THAT OVERWASH COULD OCCUR AGAIN
THIS EVENING AROUND THE TIME OF HIGH TIDE AT 03Z. THE DAYCREW WILL
NEED TO MONITOR THIS FURTHER.-- End Changed Discussion --
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.CAR WATCHES/WARNINGS/ADVISORIES...
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ME...COASTAL FLOOD ADVISORY FROM 9 AM THIS MORNING TO 1 PM EDT THIS
AFTERNOON FOR MEZ029.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT SUNDAY FOR ANZ050>052.-- End Changed Discussion --
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$$
NEAR TERM...HEWITT
SHORT TERM...MIGNONE
LONG TERM...MIGNONE
AVIATION...HEWITT/MIGNONE
MARINE...HEWITT/MIGNONE
HYDROLOGY...HEWITT
TIDES/COASTAL FLOODING...HEWITT