CAR issues Area Forecast Discussion (AFD) 958 FXUS61 KCAR 140408 AFDCAR AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 1208 AM EDT MON JUL 14 2014 .SYNOPSIS... LOW PRESSURE WILL TRACK INTO QUEBEC FROM CENTRAL CANADA TONIGHT. AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL SLOWLY CROSS THE REGION EARLY THIS WEEK FOLLOWED BY A RETURN OF HIGH PRESSURE LATE IN THE WEEK. && .NEAR TERM /THROUGH MONDAY/... MIDNIGHT UPDATE...RAISED DEW POINTS A COUPLE DEGREES DOWNEAST OVERNIGHT. OTHERWISE, NO MAJOR CHANGES THIS PERIOD. LIGHT SPOTTY SHOWERS CONTINUE ACROSS THE AREA AND WILL PUSH TOWARD THE EAST EARLY THIS MORNING. PERIODS OF SHOWERS WILL PERSIST THROUGH THE NIGHT, BUT PROBABLY NO THUNDERSTORMS. EXPECT A GENERALLY DRY DAY FOR MONDAY AS THE FRONT MOVES JUST EAST OF THE AREA. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... LATEST TRENDS FROM TDYS 12Z MODEL GUIDANCE IS A LITTLE SLOWER WITH THE RETURN OF CLDNSS AND SHWRS FROM S TO N BACK INTO THE FA MON NGT. DESPITE THIS...MOST LCTNS...EVEN ACROSS THE FAR N SHOULD BE EXPERIENCING SHWRS BY MIDDAY TUE. PROJECTED MODEL SOUNDINGS DO SHOW A LITTLE MLCAPE IN AN ENVIRONMENT CHARACTERIZED BY STRONG MID TO UPPER LVL WIND SHEAR TUE AFTN. SO FOR NOW...WE WILL MENTION A CHC OF THUNDER TUE AFTN/EVE...BUT WILL HOLD OFF ON ENHANCED WORDING FOR NOW GIVEN HOW SKINNY THE FCST CAPE IS FOR THESE PDS. OTHERWISE...SHWRS WILL CONT OVRNGT TUE INTO WED MORN AS THE COLD FRONT CONTS IT SLOW MARCH WELL AHEAD OF AN UPPER TROF ADVCG EWRD FROM CNTRL CAN AND THE GREAT LKS. WITH FAIRLY HI PWS...CANNOT RULE OUT THE POTENTIAL OF LCLZD HVY RNFL...BUT TO PIN POINT THIS NOW WITH FCST 6HRLY QPF FCSTS WOULD BE DIFFICULT AT BEST...SO FOR NOW WILL CONT WITH MODEL CONSENSUS 6 HRLY QPF...WHICH WILL TRUNCATE LOCALIZED QPF BULLSEYE MAXS...BUT SHOULD GIVE A BETTER CHC OF GETTING RELATIVE TMG OF HIGHER POPS. BASED ON THE CONSENSUS OF MODELS...WE BEGIN SLOWLY ENDING SHWRS W TO E ACROSS THE FA MIDDAY WED THRU THE AFTN...WITH SCT SHWRS PERHAPS HOLDING ON ACROSS THE SE ME BOOT HEEL INTO WED NGT. WITH LITTLE IN THE WAY OF FCST CAPE FOR WED FROM MODELS ATTM...WE WILL HOLD OFF ANY MENTION OF THUNDER FOR WED THIS UPDATE. OTHERWISE...TEMPS THIS PD WILL FEATURE NEAR OR SLIGHTLY BELOW NORMAL HIGHS AND ABV NORMAL LOWS...TYPICAL OF A TROP SRLY WIND FLOW REGIME ARRIVING FROM THE GULF OF ME. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... WED NGT AND THU WILL FEATURE SLOW CLRG FROM WNW TO ESE ACROSS THE FA. BOTH HI AND LOW TEMPS WED NGT THRU THU NGT WILL BE A LITTLE BELOW NORMAL...WITH HI TEMPS RECOVERING TO NEAR SEASONAL NORMS ON FRI AND ABV NORMS MOST LCTNS ON SAT UNDER MCLR SKIES AS HIGH PERES ALF BEGINS TO BUILD OVR THE NE U.S. LONGER RANGE MODELS THEN INDICATE INCREASING CLDNSS ACROSS THE SW TWO THIRDS OF THE FA SAT NGT AND PERHAPS A CHC OF SHWRS AND A LITTLE COOLER TEMPS OVR THESE PTNS OF THE FA ON SUN AS A S/WV FROM THE OH VLY TRIES TO UNDERCUT THE UPPER RIDGE FROM THE SW. && .AVIATION /04Z MONDAY THROUGH FRIDAY/... NEAR TERM: EXPECT IFR/MVFR CONDITIONS DEVELOPING LATER TONIGHT THEN IMPROVING TO VFR AFTER DAWN MONDAY AND PERSISTING WITH VFR THROUGH MONDAY AFTERNOON. SHORT TO LONG TERM: VFR ALL TAF SITES XPCTD MON EVE...THEN CONDITIONS LOWERING FROM S TO N IN NS/SHWRS TO MVFR LATE MON NGT INTO TUE MORN...THEN LOWERING TO IFR/LIFR IN CONTD SHWRS AND PATCHY FOG TUE NGT. CONDITIONS SHOULD SLOWLY IMPROVE FROM W TO E TO VFR BEHIND A SLOW MOVG COLD FRONT ON WED THEN REMAIN VFR INTO THE LATE WEEK. && .MARINE... NEAR TERM: HAVE USED THE NAM12 TO INITIALIZE THE SUSTAINED WIND GRIDS. WILL LOWER MODEL WINDS BY 30 PERCENT. FOR WAVES: EXPECT HIGH BIAS FOR WAVE MODEL WINDS IN THE GULF OF MAINE RESULTING IN HIGH WAVE FORECAST. HAVE RUN THE NEAR SHORE WAVE MODEL ON FORECAST WIND GRIDS. THIS SHOULD ELIMINATE PART OF THE BIAS ISSUE HOWEVER SOME OF COLDER SEA SURFACE TEMPERATURES BEYOND THE BOUNDARY OF NEAR SHORE MODEL. BASED ON CURRENT SPECTRAL INFORMATION FROM 44027 AND WNA/SPECTRAL...LONG PERIOD WAVES APPEAR TO BE 1 FOOT OR LOWER SO THIS IS NOT BIG FACTOR AND GULF OF MAINE WIND PRIMARY SYSTEM... AT LEAST UNTIL FETCH LENGTHENS TO SOUTH BEYOND THIS FORECAST PERIOD. SHORT TO TERM: WITH A SSW 10 TO 20 KT WIND FETCH AHEAD OF A SLOW MOVING COLD FRONT...WE STILL THINK THERE WILL BE A PD OF HAZ SCA WV HTS OVR OUR OUTER MZS050-051 TUE AND TUE NGT. ONSET HOWEVER...WILL BE ABOUT 12 TO 18 HRS SLOWER THAN WW3 GUIDANCE... WHICH CONTS TO EXHIBIT ITS WARM SEASON SFC WIND SPEED HI BIAS. TO CORRECT FOR THIS...WE LEANED MORE TOWARD SWAN GUIDANCE...OR ABOUT 65 TO 80 PERCENT OF WW3 WV GUIDANCE HTS. WV HTS SHOULD FALL BLO SCA THRESHOLD (5 FT) DURING THE DAY WED AND THEN REMAIN SO FOR THE REST OF THE WEEK. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...NONE. && $$ NEAR TERM...BLOOMER
Posted on: Mon, 14 Jul 2014 04:08:27 +0000
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