Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 280000 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 700 PM EST SAT DEC 27 2014 .SYNOPSIS... HIGH PRESSURE MOVING OFF THE ATLANTIC COAST WILL CONTINUE MOVING TO THE EAST TONIGHT. A COLD FRONT WILL BRING RAIN SHOWERS SUNDAY. CANADIAN HIGH PRESSURE THEN BUILDS OVER THE NORTHEAST USA AND BRINGS COLDER WEATHER FOR MUCH OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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7 PM UPDATE...MADE ONLY MINOR UPDATES TO THE SKY AND TEMPERATURE FORECAST TO ACCOUNT FOR LATEST TRENDS. OTHERWISE...THE FORECAST IS ON TRACK WITH A FEW SCATTERED CLOUDS MOVING THROUGH SOUTHERN NEW ENGLAND. TONIGHT... CLOUDS OVER THE GREAT LAKES/OHIO VALLEY AREA WILL SPREAD EAST TONIGHT. LOW CLOUDS OVER THE EASTERN GREAT LAKES MAY BREAK UP AS THEY APPROACH THIS EVENING...BUT THE MORE SUBSTANTIAL CLOUDS OVER OHIO/KENTUCKY SHOULD HOLD TOGETHER. PER SATELLITE IMAGERY...THESE LATER CLOUDS EXTRAPOLATE INTO NEW ENGLAND AROUND/AFTER MIDNIGHT. LOW PRESSURE IN THE GREAT LAKES WILL PASS NORTH OF NEW ENGLAND LATER TONIGHT. IN THE PROCESS IT WILL SWING A COLD FRONT INTO NORTHERN AND WESTERN NEW ENGLAND TOWARD MORNING. WE ARE EXPECTING A FEW SHOWERS OUT AHEAD OF THIS FRONT LATE TONIGHT WITH THE BEST CHANCE IN THE HILLS WEST OF THE CT RIVER. FAIR SKIES WILL ALLOW TEMPS TO COOL THIS EVENING. AS CLOUDS MOVE IN THE COOLING WILL END AND TEMPS SHOULD RISE A LITTLE. WE FOLLOWED THIS NON DIURNAL TREND FOR HOURLY TEMPS.
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&& .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/... OVERVIEW...TROUGH DIGS OVER THE WESTERN USA MAKING ROOM FOR COLD AIR TO MOVE SOUTH INTO THE WESTERN USA. SHORTWAVE NORTH OF THE GREAT LAKES MOVES EAST...WITH THE SHORTWAVE AXIS CROSSING NEW ENGLAND SUNDAY NIGHT. THE UPPER FLOW REMAINS GENERALLY WESTERLY THROUGH THE PERIOD. SUNDAY...COLD FRONT MOVES ACROSS SOUTHERN NEW ENGLAND SUNDAY. MODEL CROSS SECTIONS SHOW DEEP MOISTURE DURING THE DAY WITH PRECIPITABLE WATER VALUES BRIEFLY RISING TO AROUND 1 INCH. THERE IS SUFFICIENT LIFT AND MOISTURE TO SUPPORT SHOWERS. WE HAVE BUMPED POPS UP TO 50-60 PERCENT. BEHIND THE FRONT...WINDS SHIFT TO WEST- NORTHWEST. VERTICAL PROFILES SUGGEST POTENTIAL MIXING OF 20 KNOT WINDS TO THE SURFACE IN GUSTS. TEMPS IN THE MIXED LAYER WOULD SUPPORT MAX SFC TEMPS IN THE 40S...MAYBE AROUND 50 ALONG THE SOUTH COAST. DEPENDING ON HOW FAST THE COLDER AIR MOVES IN IT IS POSSIBLE THAT EXTREME NW MASS MAY STAY IN THE 30S. SUNDAY NIGHT...THE LAST OF THE SHOWERS SHOULD MOVE SOUTH OF THE SOUTH COAST AND ISLANDS. DRIER AIR WILL MEAN A CLEARING TREND OVERNIGHT. WITH DEWPOINTS IN THE 20S AND LIGHT NORTHWEST WINDS...EXPECT TEMPS AWAY FROM THE COAST TO DIP BELOW FREEZING. && .LONG TERM /MONDAY THROUGH SATURDAY/... HIGHLIGHTS... * DRY WEATHER THROUGH MOST OF THE WORK WEEK * SEASONABLE TO PERHAPS SLIGHTLY BELOW NORMAL TEMPERATURES EXPECTED * NEXT SHOT OF PRECIP POTENTIALLY LATE FRIDAY INTO SATURDAY MODELS ARE IN GOOD AGREEMENT THROUGH MUCH OF THE LONG TERM WITH NORTHERLY FLOW AND COOLER TEMPERATURES TO START THE WEEK OFF. GENERAL FLOW SHIFTS TO THE SOUTHWEST AS LOW PRESSURE MOVES OVER HUDSON BAY WITH MODERATING TEMPERATURES EXPECTED WEDNESDAY AND THURSDAY. MODELS START TO SHOW SOME TIMING DISCREPANCIES FOR FRIDAY INTO THE WEEKEND WITH THE GFS A BIT FASTER THAN THE ECMWF WITH A LOW PRESSURE SYSTEM MOVING THROUGH QUEBEC AND INTO THE MARITIMES. THE GFS ALSO HINTS AT A SECONDARY LOW DEVELOPING OVER THE TRI-STATE AREA DURING THIS PERIOD. WHETHER OR NOT THIS OCCURS WILL AFFECT TEMPERATURE PROFILES AS WELL AS LOCATIONS AND AMOUNTS OF PRECIPITATION. AT THIS POINT...WILL USE A BLEND OF THE MODELS FOR THIS TIME PERIOD WHILE THE NEXT FEW RUNS SHAKE OUT. MONDAY AND TUESDAY...DRY BUT MORE SEASONABLE WEATHER IS EXPECTED AS HIGH PRESSURE BUILDS INTO THE GREAT LAKES AND SURFACE WINDS ALLOW COLDER AIR TO DRAIN FROM THE NORTH. WEDNESDAY AND THURSDAY...WINDS SHIFT TO THE SOUTHWEST AS LOW PRESSURE MOVES OVER HUDSON BAY AND THEN EASTWARD THROUGH QUEBEC. WHILE THERE IS A COLD FRONT ASSOCIATED WITH THE LOW...MODELS ARE FORECASTING THIS TO STAY WELL TO OUR NORTH AT THIS TIME. THEREFORE...DRY WEATHER WILL PERSIST BUT TEMPERATURES WILL MODERATE A BIT. FRIDAY AND SATURDAY...AS STATED ABOVE THIS IS THE PERIOD OF GREATEST UNCERTAINTY. THERE ARE BOTH TIMING AND TRACK DIFFERENCES BETWEEN THE ECMWF AND THE GFS. A LOW PRESSURE SYSTEM AND/OR COLD FRONT WILL AFFECT SOUTHERN NEW ENGLAND DURING THIS TIME PERIOD...BRINGING A DECENT ROUND OF PRECIPITATION TO THE REGION. AS THE MODELS ARE INCONSISTENT WITH THE TRACK OF THE STORM...IT IS TOO EARLY TO TELL WHETHER THIS WILL BE MORE OF A WINTRY PRECIP OR RAIN. && .AVIATION /23Z SATURDAY THROUGH THURSDAY/...
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FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. TONIGHT...HIGH CONFIDENCE. MAINLY VFR. INCREASING CLOUDS FROM WEST TO EAST AFTER MIDNIGHT. LOW PROBABILITY OF MVFR CIGS/LOCAL MVFR VSBYS IN SCATTERED SHOWERS ACROSS WESTERN MA AND NW CT WELL AFTER MIDNIGHT. SUNDAY...HIGH CONFIDENCE. GENERALLY VFR BUT WITH MVFR CEILINGS AND VSBYS POSSIBLE IN ANY RAIN SHOWERS. SW WINDS 10 TO 20 KT SHIFTING TO THE NW. SUNDAY NIGHT...HIGH CONFIDENCE. VFR WITH A LIGHT NORTHWEST WIND. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. OUTLOOK...MONDAY THROUGH THURSDAY... MONDAY AND TUESDAY...HIGH CONFIDENCE. VFR. WEDNESDAY AND THURSDAY...MODERATE CONFIDENCE. VFR.
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&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH SUNDAY/...MODERATE TO HIGH CONFIDENCE. UNTIL 7 PM...WINDS AND SEAS BELOW SMALL CRAFT ADVISORY CRITERIA. TONIGHT...COLD FRONT APPROACHES FROM THE GREAT LAKES AND REACHES WESTERN NEW ENGLAND TOWARD MORNING. WINDS WILL INCREASE FROM THE SOUTHWEST WITH GUSTS NEAR 25 KNOTS POSSIBLE BY DAYBREAK. SUNDAY...COLD FRONT MOVES ACROSS NEW ENGLAND DURING THE MORNING AND ACROSS THE WATERS DURING THE AFTERNOON. SOUTHWEST WINDS BECOME WEST WITH FREQUENT GUSTS TO 25 KNOTS...AND SEAS BUILD TO AROUND 5 FEET ON THE OUTER WATERS. WINDS AND SEAS DIMINISH TOWARD EVENING. A SMALL CRAFT ADVISORY IS IN EFFECT FOR MOST OF THE WATERS FOR SUNDAY. SUNDAY NIGHT...WINDS AND SEAS DIMINISH. SEAS MAY LINGER NEAR 5 FEET ON THE OUTER PORTIONS OF THE OUTER WATERS OVERNIGHT. OUTLOOK...MONDAY THROUGH THURSDAY... MONDAY THROUGH WEDNESDAY...HIGH CONFIDENCE. QUIET BOATING CONDITIONS EXPECTED. NORTHERLY WINDS MONDAY WILL SHIFT TO THE SOUTHWEST AND WEST TUESDAY AND WEDNESDAY. THURSDAY...MODERATE CONFIDENCE. SEAS START TO BUILD AS HIGH PRESSURE MOVES AWAY FROM THE WATERS. WESTERLY WINDS INCREASE WITH LOW PRESSURE OVER THE GREAT LAKES AND HIGH PRESSURE MOVING OFF THE MID- ATLANTIC. SMALL CRAFT CONDITIONS ARE POSSIBLE DURING THIS TIME FRAME. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EST SUNDAY FOR ANZ232- 235-237-250-254>256. && $$ SYNOPSIS...WTB/RLG NEAR TERM...WTB/RLG SHORT TERM...WTB LONG TERM...RLG AVIATION...WTB/RLG MARINE...WTB/RLG

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