Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 162040 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 440 PM EDT SUN JUN 16 2013 .SYNOPSIS...
-- Changed Discussion --
A COLD FRONT FROM THE GREAT LAKES WILL SLIDE ACROSS SOUTHERN NEW ENGLAND TONIGHT. A SECOND COLD FRONT MAY STALL ACROSS THE REGION MONDAY...THEN SLOWLY MOVE OFFSHORE LATE TUESDAY OR TUESDAY NIGHT. LARGE HIGH PRESSURE WILL BRING MAINLY DRY AND SEASONABLE CONDITIONS WEDNESDAY THROUGH FRIDAY...THEN WILL ANCHOR SOUTH OF NEW ENGLAND SATURDAY. A WEAK FRONT MAY BRING WIDELY SCATTERED SHOWERS NEXT WEEKEND.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
-- Changed Discussion --
THROUGH MIDNIGHT... COLD FRONT IN CENTRAL NEW YORK WITH 1 MB/HOUR PRESSURE FALLS OVER THE HUDSON VALLEY AT MID AFTERNOON. RADAR SHOWS SHOWERS LEADING THIS FRONT...WITH MOST OF THE ACTION OVER THE ADIRONDACKS AND NORTHERN VT/NH MOVING EAST OR EAST-NORTHEAST. SHOWERS OVER SOUTHERN VT WILL CROSS CHESHIRE AND HILLSBOROUGH COUNTIES BY 6 PM. TRAILING SHOWERS MORE PROXIMATE TO THE COLD FRONT WILL CROSS SOUTHERN NH BETWEEN 7 AND 10 PM. FARTHER SOUTH...JUST SOME SPRINKLES/LIGHT SHOWERS UNTIL EVENING. AN AREA OF LIGHT SHOWERS CLOSE TO THE COLD FRONT WILL ENTER THE REGION WEST-EAST 6-9 PM AND EXIT WEST-EAST 7-10 PM. UPSTREAM RAINFALL FROM THE BROADER NORTHERN AREA HAS TOTALED 0.2 TO 0.5 INCHES. MEANWHILE RAINFALL SOUTH OF THE NY THRUWAY HAS BEEN LESS THAN 0.10 INCHES. OVERNIGHT... CLEARING IS ENTERING FAR WESTERN NY BUT WITH PLENTY OF LOW LEVEL MOISTURE IN THE FORM OF CUMULUS CLOUDS OVER SOUTHERN ONTARIO. EXPECT THIS CLEARING TO MOVE INTO SOUTHERN NEW ENGLAND AFTER MIDNIGHT. THE LOW LEVEL MOISTURE AND DIMINISHED WIND MAY ALLOW FOG PATCHES TO FORM OVERNIGHT. DEWPOINTS UPSTREAM ARE 55-60...WHICH IS A GOOD TARGET FOR OVERNIGHT MIN TEMPS. WE USED A BLEND OF MOS VALUES.
-- End Changed Discussion --
&& .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
-- Changed Discussion --
MONDAY... ONE SURFACE LOW MOVES OFF THROUGH THE MARITIMES. THE UPPER TROUGH LINGERS OVER QUEBEC AND EXTENDS THROUGH THE NORTHEAST USA. A 105 KNOT UPPER JET MOVES THROUGH THE TROUGH WITH THE RIGHT ENTRANCE REGION OVER SOUTHERN NEW ENGLAND DURING THE DAY. MEANWHILE A SHORTWAVE MOVES THROUGH THE CYCLONIC FLOW AND DRIVES A SECOND COLD FRONT THROUGH THE ST LAWRENCE VALLEY INTO NEW ENGLAND/NY. STABILITY PARAMETERS TELL A FAVORABLE STORY WITH LI AT -1/-2...TOTALS 46-50...SBCAPE REACHING 200-500 J/KG. THIS SHOULD SUPPORT SHOWERS/SCATTERED TSTMS DEVELOPING INLAND DURING THE AFTERNOON AND SPREADING SOUTH/EAST DURING THE EVENING. TEMPS AT 850 MB 12-14C AND GOOD MIXING DURING THE MORNING/AFTERNOON SHOULD SUPPORT MAX TEMPS IN THE LOW TO MID 80S. MONDAY NIGHT... THE COLD FRONT MOVES ACROSS THE REGION MONDAY NIGHT. DIURNAL INSTABILITY WILL BE FADING...BUT WE WILL CONTINUE TO HAVE THE UPPER JET NEARBY WITH FAVORABLE UPPER VENTING TO MAINTAIN SOME SUPPORT FOR CONVECTION. WE HAVE MAINTAINED CHANCE POPS THROUGH THE NIGHT.
-- End Changed Discussion --
&& .LONG TERM /TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
HIGHLIGHTS... * SCATTERED SHOWERS/ISOLATED TSTMS DURING TUESDAY AS FRONT SLOWLY MOVES ACROSS REGION. * DRY AND SEASONABLE WEATHER FOR THE MIDDLE AND END OF THE WEEK OVERVIEW AND MODEL PREFERENCES... MEDIUM RANGE MODELS SIGNALING BROAD UPPER LEVEL LOW PRES ACROSS QUEBEC AT THE START OF THE LONG TERM PERIOD...KEEPING A LONG WAVE TROUGH ACROSS NY STATE INTO PA WITH WEAK SHORT WAVES RIDING THROUGH THE BASE OF THIS LOW. GENERAL W-SW FLOW WILL CAUSE A COLD FRONT TO ONLY SLOWLY CROSS THE REGION...BUT SHOULD MOVE OFF AS THE UPPER LEVEL SYSTEM WEAKENS AND SHIFTS E BY ABOUT MID WEEK. LOOKS LIKE A DRY W-NW FLOW ALONG WITH LARGE SURFACE HIGH PRES WILL BRING SEVERAL DAYS OF DRY CONDITIONS WITH NEAR SEASONABLE TEMPS. NOTING INCREASING VARIANCE IN MODEL SOLUTIONS AS THE HIGH BUILDS OFF THE MID ATLC COAST AROUND NEXT WEEKEND AS THEIR HANDLING OF ANOTHER APPROACHING FRONT. WENT ALONG WITH WPC GUIDANCE IN KEEPING THE FRONT TO THE NW OF THE REGION...WHICH MEANS MODERATING TEMPS WITH INCREASING HUMIDITY AT THIS POINT. DETAILS... TUESDAY-TUESDAY NIGHT... SECOND FRONT TENDING TO RUN PARALLEL TO THE W-SW UPPER FLOW IN PLACE...SO WILL BE SLOW TO CLEAR THE REGION. KEPT CHANCE POPS GOING. WILL ALSO SEE MARGINAL INSTABILITY...SO KEPT MENTION OF ISOLD TSTMS AS WELL. DOES LOOK LIKE THE UPPER LEVEL SYSTEM WILL SHIFT E LATE TUE/TUE NIGHT...SO FRONT SHOULD MOVE OFFSHORE AS HIGH PRES MOVES OUT OF THE GREAT LAKES. SKIES SHOULD CLEAR FROM NW-SE TUE NIGHT...THOUGH MAY LINGER INTO WED ALONG THE S COAST...CAPE COD AND THE ISLANDS. WEDNESDAY THROUGH FRIDAY... LARGE HIGH PRES WILL BUILD ACROSS THE REGION OUT OF NY STATE. EXPECT DRY CONDITIONS DURING THIS TIMEFRAME. HIGHS WILL START OFF CLOSE TO OR A LITTLE BIT BELOW SEASONAL NORMS FOR WED...THEN WILL REBOUND TO THE LOWER 80S BY FRIDAY. THE HIGH WILL BUILD OFFSHORE DURING FRIDAY...SO WINDS WILL START TO SHIFT TO S-SW WHICH WILL HELP TO BRING MILDER AIR TO THE REGION. MAY SEE ISOLD SHOWER/TSTM ACTIVITY DURING THE AFTERNOON/EVENING ON FRI AS WEAK TROUGH TRIES TO MOVE THROUGH BUT WEAKENS. MAY BE JUST ENOUGH LL MOISTURE TO KICK OFF DIURNAL CONVECTION. ONLY MENTIONED SLIGHT CHANCE POPS AT THIS POINT. SATURDAY-SUNDAY... WITH INCREASING SOLUTION SPREAD AMONG THE MODELS...NOT QUITE AS CONFIDENCE WITH THIS PORTION OF THE FORECAST. WITH RETURN SW FLOW IN PLACE AND INCREASING HUMIDITIES...COULD SEE WIDELY SCT DIURNAL SHOWERS DEVELOP ON SATURDAY. FOR NEXT SUNDAY...MAY SEE NEXT FRONTAL SYSTEM APPROACH. AGAIN...KEPT ONLY SLIGHT CHANCE POPS GOING BUT TIMING IS IN QUESTION.
-- End Changed Discussion --
&& .AVIATION /21Z SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. OVERVIEW...HIGH CONFIDENCE THROUGH MONDAY NIGHT. THROUGH 00Z... AREA OF SHOWERS OVER NEW YORK IS MOSTLY MOVING NORTHEAST INTO QUEBEC AND NORTHERN/CENTRAL VERMONT. ISOLATED SHOWERS SOUTH OF THERE WHICH MAY BRING BRIEF LIGHT PRECIP. BEST CHANCE OF THIS ALONG WITH BRIEF MVFR VSBYS WOULD BE LATE AFTN/EVENING. BEST CHANCE OF SHOWERS WILL BE AT MHT...LEAST CHANCE AT ACK. TONIGHT... LINGERING SHOWERS POSSIBLE EARLY TONIGHT. ENOUGH INSTABILITY FOR ISOLATED THUNDER. A COLD FRONT MOVES ACROSS SOUTHERN NEW ENGLAND AROUND 06Z WITH CLEARING BEHIND. THE CLEARING MAY ALLOW FOR SOME PATCHY MVFR FOG ESPECIALLY ALONG THE SOUTH COAST REGION. MONDAY AND MONDAY NIGHT... MAINLY VFR THROUGH THE DAY. ANOTHER WEAK FRONT APPROACHES DURING THE AFTERNOON AND MOVES THROUGH AT NIGHT. THIS MAY TRIGGER SCATTERED SHOWERS AND WIDELY SCATTERED TSTMS. AREAS OF MVFR/IFR POSSIBLE IN FOG MONDAY NIGHT...ESPECIALLY NEAR THE SOUTH COAST. KBOS TERMINAL...HIGH CONFIDENCE IN OVERALL TAF TRENDS...SLIGHTLY LOWER CONFIDENCE IN TIMING OF SHOWERS. KBDL TERMINAL...HIGH CONFIDENCE IN OVERALL TAF TRENDS...SLIGHTLY LOWER CONFIDENCE IN TIMING OF SHOWERS. OUTLOOK...TUESDAY THROUGH FRIDAY... TUESDAY THROUGH TUESDAY NIGHT...MODERATE CONFIDENCE. MVFR POSSIBLE AT TIMES IN SCT SHOWERS AND TSTMS. WEDNESDAY THROUGH FRIDAY...HIGH CONFIDENCE. VFR.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. THROUGH THIS EVENING... REPORTED WIND GUSTS HAVE BEEN 20 KNOTS OR LESS OVER THE NEAR SHORE WATERS. WE HAVE OPTED TO DROP SMALL CRAFT HEADLINES IN THOSE AREAS. TONIGHT...MODERATE TO HIGH CONFIDENCE. A COLD FRONT APPROACHES THE WATERS TONIGHT. THE STEADY SOUTHWEST WIND WILL BUILD SEAS ON THE SOUTHERN/SOUTHEAST OUTER WATERS WITH HEIGHTS REACHING 5-6 FEET. WINDS AHEAD OF THE FRONT MAY APPROACH 25 KNOTS BUT THIS IS LESS CERTAIN. WE HAVE MAINTAINED THE SMALL CRAFT ADVISORY FOR THE SOUTHERN WATERS AND EXPANDED IT INTO THE WATERS EAST OF CAPE COD. MONDAY...MODERATE TO HIGH CONFIDENCE. THE COLD FRONT MOVES OFFSHORE AND DISSIPATES. ANOTHER FRONT WILL APPROACH FROM THE GREAT LAKES LATE IN THE DAY. WEATHER ON THE WATERS WILL BE QUIET MUCH OF THE DAY WITH DIMINISHING SEAS. SCATTERED SHOWERS/TSTMS WILL DEVELOP INLAND AND MAY BECOME A FACTOR ON THE WATERS LATE IN THE DAY/EVENING. MONDAY NIGHT...MODERATE CONFIDENCE. SHOWERS/SCATTERED TSTMS WILL AFFECT THE WATERS DURING THE NIGHT. THE COLD FRONT WILL MOVE TO THE SOUTH NEW ENGLAND COAST BY TUESDAY MORNING AND STALL. SEAS SHOULD REMAIN BELOW 5 FEET. WINDS SHOULD REMAIN BELOW 25 KNOTS EXCEPT IN THE VICINITY OF ANY TSTMS. OUTLOOK...TUESDAY THROUGH FRIDAY... MODERATE CONFIDENCE THROUGH THE PERIOD. WINDS AND SEAS BELOW SMALL CRAFT CRITERIA FOR THE MAJORITY OF THE PERIOD. N-NE WIND GUSTS MAY APPROACH 25 KT LATE TUE NIGHT AND WED ON THE OUTER WATERS E AND S OF CAPE COD ALONG WITH MARGINAL 5 FOOT SEAS.
-- End Changed Discussion --
&& .HYDROLOGY... DRY WEATHER IS ALLOWING RIVERS ACROSS SOUTHERN NEW ENGLAND TO CREST AND RECEDE. WE WILL NEED TO MONITOR FOR ANY SHOWERS/TSTMS MONDAY WHERE RUNOFF COULD CHANGE THE TIMING FOR THE RECEDING WATERS. RIVER FORECAST POINTS WHERE FLOOD WARNINGS ARE STILL IN EFFECT AS OF 330 PM. ALL EXCEPT THE CHARLES RIVER MAY BE ENDED SOMETIME THIS EVENING OR TONIGHT. IN CT... FARMINGTON RIVER AT SIMSBURY IS NEAR FLOOD STAGE AND FALLING CONNECTICUT RIVER AT MIDDLE HADDAM ABOVE FLOOD STAGE AND FALLING IN MA... CHARLES RIVER AT DOVER AT CREST AND STEADY IN RI... PAWTUXET RIVER AT CRANSTON ABOVE FLOOD STAGE AND FALLING IN ADDITION...AN AREAL FLOOD WARNING REMAINS IN EFFECT FOR SOUTHWESTERN WASHINGTON COUNTY IN RI WHERE THE LOWER PAWCATUCK RIVER REMAINS IN FLOOD. REFER TO THE LATEST FLOOD STATEMENTS FOR SPECIFIC FORECASTS. && .BOX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EDT MONDAY FOR ANZ254>256.
-- End Changed Discussion --
&& $$ SYNOPSIS...WTB/EVT NEAR TERM...WTB/EVT SHORT TERM...WTB/EVT LONG TERM...EVT AVIATION...WTB/EVT MARINE...WTB/EVT HYDROLOGY...WTB

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.