Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 200603 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 203 AM EDT SUN APR 20 2014 .SYNOPSIS... HIGH PRESSURE IN CONTROL WILL RESULT DRY WEATHER INTO TUESDAY. MILD AFTERNOON/S EXCEPT FOR CHILLY SEA BREEZES ALONG THE COAST SUNDAY. A LOW PRESSURE AND AN ASSOCIATED COLD FRONT WILL LIKELY BRING A PERIOD OF WET WEATHER TUESDAY AFTERNOON INTO WEDNESDAY. ANOTHER HIGH PRESSURE ARRIVES WITH MORE DRY...PLEASANT CONDITIONS FOR LATE NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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150 AM UPDATE... BAND OF HIGH CLOUDS CONTINUES ACROSS MOST OF THE REGION EARLY THIS MORNING...THE FAR NORTHERN EDGE OF HIGH LEVEL MOISTURE WORKING UP THE COAST AROUND STRONG LOW PRES OFF THE SE U.S. COAST AT 05Z. LOOKS LIKE CLOUDS ARE THIN ENOUGH TO ALLOW TEMPS TO DROP... ESPECIALLY ACROSS S NH/N AND W MA WHERE TEMPS HAVE ALREADY DROPPED TO THE LOWER-MID 30S. WINDS HAVE ALSO DIMINISHED TO LGT/VRBL OR CALM THERE AS WELL. BANDS OF THE HIGH CLOUDS WILL CROSS THE REGION THROUGH THE REMAINDER OF THE NIGHT...BUT EXPECT MOSTLY CLEAR CONDITIONS ON AVERAGE ESPECIALLY ACROSS E MA/RI INTO NE CT. KEPT SIMILAR TEMP DROP OVERNIGHT...THOUGH SOME SPOTS MAY NOT DROP QUITE AS FAST DEPENDING UPON HOW MUCH OF THE CLOUDS CROSS THE REGION. WILL CONTINUE TO MONITOR. HAVE UPDATED REMAINING GRIDS TO BRING CONDITIONS CURRENT.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/... HIGH PRESSURE OVER EASTERN CANADA WILL SHIFT TO A POSITION JUST SOUTH OF THE MARITIMES LATE SUNDAY NIGHT. THIS WILL RESULT IN MOSTLY CLEAR SKIES...BUT ALSO ONSHORE WINDS. SINCE THE WATER IS STILL RATHER COLD...TEMPERATURES ALONG THE IMMEDIATE COAST SHOULD HOLD IN THE 45-50 DEGREE RANGE. ELSEWHERE...PLENTY OF SUNSHINE SHOULD BOOST MAX TEMPERATURES WELL INTO THE 50S. A FEW LOCATIONS NEAR THE CT AND MERRIMACK RIVER VALLEYS MAY REACH AROUND 60 DEGREES. WINDS WILL BE MUCH LIGHTER THAN TODAY...SO IT WILL BE A PLEASANT AFTERNOON INLAND FROM THE COAST. NOT AS IDEAL RADIATIONAL COOLING CONDITIONS SUNDAY NIGHT...SO EXPECTING SEASONABLE TEMPERATURES. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... MODEL OVERVIEW... SPLIT FLOW DOMINATES THE BEGINNING OF THE COMING WEEK WITH MAINLY ZONAL FLOW. TOWARDS THE END OF THE WEEK...THE FLOW BECOMES PHASED ON THE BACK SIDE OF A WAVE MOVING THROUGH THE REGION MIDWEEK. THIS BECOMES NEGATIVELY TILTED...BUT SHOULD DO SO JUST OFF THE EAST COAST. DISAGREEMENT OCCURS AROUND THE TIME THE PHASED FLOW COMES IN AS TO HOW FAST THE WAVE MOVES THROUGH. USUAL MODEL BIASES...ENSEMBLE GUIDANCE AND THE WPC SOLUTION GUIDE THIS FORECAST AS TO THE SPEED OF THE PASSAGE. ANOTHER WAVE ARRIVES DURING THE EARLY WEEKEND. DAILIES... MONDAY TO TUESDAY...HIGH DOMINATING THE NORTHEAST USA FOR THE PAST FEW DAYS SLOWLY MEANDERS TO THE EAST. RETURN FLOW ON THE BACK OF THE HIGH ALLOWS THE AIRMASS TO GET MILDER. BOTH DAYS SEE 850MB TEMPS AROUND 8-10C AND MODEL MIXING UP TO AROUND 900MB SO COULD SEE IT APPROACH 70F ESPECIALLY SINCE MIXING MAY BE UNDERDONE. MONDAY...WITH ITS WEAK WINDS OF LESS THAN 10KTS AND WARMER TEMPS ON LAND...MAY SEE A WEAK SEA BREEZE DEVELOP. A COLD FRONT APPROACHES THE REGION TUESDAY NIGHT WITH MOIST COLUMNS...PWATS 1SD ABOVE NORMAL AND K- INDEX APPROACHING 30. WITH THE AFOREMENTIONED CONVECTIVE PARAMETERS AND TOTAL OF TOTALS NEARING 50 CAN/T RULE OUT THE POSSIBILITY OF THUNDER. PRECIP SHOULD AMOUNT TO AROUND 0.25". LLJ AT 850 MB APPROACHING 30KTS SO SOME GUSTY WINDS IN THE MID TO UPPER 20S SHOULD BE SEEN. WEDNESDAY AND THURSDAY...COLD FRONTAL PASSAGE OCCURS EARLY IN THE MORNING. NEGATIVELY ANOMALOUS TROUGH FOLLOWS IT INDICATING COLD AIR 1SD BELOW NORMAL TO FOLLOW THE FRONT FOR THURSDAY. HOWEVER...RISING HEIGHTS FROM MIDLEVEL RIDGE OVER THE EASTERN HALF OF THE COUNTRY SHOULD KEEP TEMPS FROM FALLING TOO MUCH. GUSTY WINDS SHOULD BE SEEN DUE TO A LLJ FROM THE NORTHWEST AND FROM THE PHASED WINDS MIXING DOWN. FRIDAY...WITH HIGH PRESSURE MOVING EAST FROM THE SOUTHEASTERN STATES HAVE KEPT THE REGION DRY AND SLIGHTLY ABOVE AVERAGE WITH THE HIGH PRESSURE/S RETURN FLOW. SATURDAY...A BIT OF A MODEL DISCREPANCY AS TO WHEN THE LOW PRESSURE SHOULD MAKE ITS WAY INTO THE REGION...BUT HAVE GONE WITH CHANCE POPS TO COVER THE AREA. ALSO LOOKS TO BE SOME CONVECTIVE NATURE TO THIS STORM. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM...THROUGH SUNDAY NIGHT...HIGH CONFIDENCE. THROUGH 12Z...VFR. EXPECT LIGHT/VRBL OR CALM WINDS. TODAY AND TONIGHT...VFR CONDITIONS. WINDS BECOME NE AROUND 10 KT THIS MORNING...SHIFTING TO E-SE AND DIMINISHING THIS AFTERNOON...THEN TO S TONIGHT. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...MONDAY THROUGH THURSDAY... MONDAY INTO TUE...HIGH CONFIDENCE. MAINLY VFR. MAINLY SOUTHWEST WINDS. TUESDAY NIGHT INTO WEDNESDAY... MODERATE CONFIDENCE...PERIODS OF MVFR/IFR IN LOW CIGS AND VSBYS DUE TO RAIN. CONDITIONS LOOKS TO IMPROVE ON WEDNESDAY BEHIND THE FRONT. W/NW WIND GUSTS TO AROUND 30 KTS POSSIBLE. THURSDAY... VFR CONDITIONS ON CLEAR SKIES AND NW WINDS AROUND 15 KTS. GUSTS TO AROUND 35 KTS OVER THE WATERS TO THE NORTH.
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&& .MARINE...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE. TONIGHT... LOOKS LIKE WE MAY SEE A PERIOD OF NORTH TO NORTHEAST 25 KNOT WIND GUSTS OVER THE EASTERN WATERS IN A SURGE OF COLD ADVECTION. KEPT THE EASTERN ATLANTIC WATERS WITH SMALL CRAFT ADVISORY HEADLINES. ITS POSSIBLE WE MAY NEED TO EXTEND THEM INTO CAPE COD BAY AND NANTUCKET SOUND FOR A TIME. SUNDAY AND SUNDAY NIGHT... WINDS SHOULD REMAIN BELOW ADVISORY THRESHOLDS ACROSS MOST OF THE WATERS. HOWEVER...MARGINAL 5 FOOT SEAS EXPECTED TO LINGER INTO THE LATE MORNING/EARLY AFTERNOON ACROSS PORTIONS OF THE EASTERN ATLANTIC WATERS BEFORE FINALLY SUBSIDING. OUTLOOK...MONDAY THROUGH THURSDAY... MONDAY INTO TUE...HIGH CONFIDENCE. HIGH PRESSURE DOMINATES THE WEATHER FOR THIS PERIOD WITH FEW S/SW GUSTS AROUND 25KTS POSSIBLE. TUE NIGHT INTO WED...MODERATE CONFIDENCE. COLD FRONT MOVES THROUGH THE REGION FROM WEST TO EAST BRINGING PERIODS OF RAIN. WAVES SHOULD REMAIN BELOW 5FT. WINDS SHOULD REMAIN BELOW 15 KTS FOR THIS PERIOD. RAIN SHOULD END AT ABOUT LATE MORNING TO MIDDAY. THURSDAY...POTENTIAL NW WINDS GUSTING TO 35 KT. EXPECT SEAS TO BUILD TO 5-8 FEET DURING THIS TIME. WILL MONITOR FOR POTENTIAL GALE CONDITIONS.
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&& .FIRE WEATHER... SUNDAY...ALTHOUGH THE DRY WEATHER CONTINUES...WINDS WILL BE MUCH LIGHTER AND HIGH TEMPERATURES A BIT LOWER. NO HEADLINES PLANNED. && .HYDROLOGY... MINOR FLOODING CONTINUES ALONG PORTIONS OF THE MAINSTEM CT RIVER. ALL POINTS HAVE FINALLY CRESTED AND ARE NOW RECEDING. SEE THE LATEST FLOOD STATEMENT FOR DETAILS. FLOOD WARNINGS REMAIN POSTED ALONG CT RIVER AT... HARTFORD AND MIDDLE HADDAM && .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ250-255. SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR ANZ254.
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&& $$ SYNOPSIS...BELK/HR NEAR TERM...EVT SHORT TERM...BELK LONG TERM...WTB/HR AVIATION...WTB/EVT/HR MARINE...BELK/EVT/HR FIRE WEATHER...STAFF HYDROLOGY...STAFF

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