Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 241753 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 153 PM EDT THU JUL 24 2014 .SYNOPSIS...
-- Changed Discussion --
HIGH PRESSURE CENTERED OVER THE OHIO VALLEY WILL BUILD EASTWARD AND PROVIDE SUNNY SKIES FRIDAY. THE HIGH SHIFTS OFFSHORE SATURDAY. THEN UNSETTLED CONDITIONS LATE IN THE WEEKEND AND INTO NEXT WEEK. A WARM FRONT APPROACHES SUNDAY BRINGING WARM HUMID AIR. A COLD FRONT THEN SWINGS ACROSS THE REGION MONDAY AND TUESDAY...AND LINGERS OFF THE EAST COAST THE MIDDLE OF NEXT WEEK.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
150 PM UPDATE... UPPER LEVEL DISTURBANCE MOVING THROUGH WILL RESULT IN CONTINUED VERY ISOLATED SPRINKLES/SHOWERS ACROSS EASTERN NEW ENGLAND THROUGH THE AFTERNOON. CERTAINLY FAR FROM A WASH OUT THOUGH...WITH DRY WEATHER DOMINATING ACROSS THE VAST MAJORITY OF THE REGION. A MIXTURE OF CLOUDS AND SUN EXPECTED ACROSS THE INTERIOR...WITH CLOUDS DOMINATING IN THE EASTERN SECTIONS. HIGH TEMPS WILL TOP OUT IN THE 70S TO THE LOWER 80S...A BIG RELIEF FROM THE HEAT AND HUMIDITY OF YESTERDAY!
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... A MOSTLY CLEAR NIGHT IS EXPECTED TONIGHT. THE ONLY EXCEPTION MAY BE ON THE ISLANDS WHERE MODELS ARE QUITE EMPHATIC ABOUT THE RETURN OF LOW CLOUDINESS AND FOG WITH LIGHT NORTHEASTERLY WIND FLOW AND DEWPOINT TEMPERATURES HANGING IN THE LOWER 60S. THE POSSIBILITY EXISTS FOR LOW VISIBILITIES ON NANTUCKET. LOWS WILL BE MUCH MORE COMFORTABLE...IN THE MID 50S TO LOWER 60S EXCEPT LOWER TO MID 60S ON THE ISLANDS. HIGH PRESSURE CENTERED OVER THE OHIO VALLEY WILL BUILD EASTWARD ON FRIDAY AND PROVIDE SUNNY SKIES TO SOUTHERN NEW ENGLAND WITH HIGHS REACHING INTO THE LOWER 80S...COOLER ON THE ISLANDS. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
-- Changed Discussion --
BIG PICTURE... MUCH OF THE UPPER FLOW REMAINS UNCHANGED THROUGH THE FORECAST PERIOD. DEEP RIDGES WILL EXTEND ACROSS WESTERN NORTH AMERICA AND THE WESTERN ATLANTIC. CLOSED LOW OVER NORTHERN QUEBEC ANCHORS A TROUGH OVER EASTERN NORTH AMERICA. SHORTWAVE EJECTING FROM THE PACIFIC NORTHWEST WILL PLOW OVER THE TOP OF THE WESTERN RIDGE...THEN MERGE WITH THE EASTERN NORTH AMERICA TROUGH OVER THE WEEKEND. THIS WILL DEEPEN THE TROUGH AND PULL ITS FEATURES FARTHER SOUTH. THE DEPTH OF THE TROUGH AND THE EXTENT OF THE RIDGES ON EITHER SIDE WILL MAKE STRAIGHT WEST-TO-EAST MOVEMENT DIFFICULT NEXT WEEK. THE MASS FIELDS AND THERMAL FIELDS OF THE GFS AND ECMWF LOOK SIMILAR IN OVERVIEW. SOME DIFFERENCES IN DETAILS EMERGE DURING THE FIRST HALF OF NEXT WEEK. THE SIMILARITY BUILDS CONFIDENCE IN THE OVERALL FLOW OF THE FORECAST. THE LONGER RANGE DIFFERENCES IN DETAIL SUPPORT USING A BLEND OF THE FORECAST DATA. THE DAILIES... FRIDAY NIGHT AND SATURDAY... THIS SHOULD BE A FAIR PERIOD BUT WITH SIGNS OF CHANGES TO COME. HIGH PRESSURE SHIFTS OFFSHORE AND THE SURFACE FLOW TURNS SOUTHWEST. ALSO INCREASING SOUTHWEST FLOW ALOFT WITH INCREASING MOISTURE AT THE CIRRUS LEVEL. CROSS SECTIONS DO SHOW SOME INCREASING MOISTURE TOWARD SATURDAY EVENING AROUND 5000 FEET AS WELL. EXPECT MOSTLY CLEAR SKIES AND LIGHT WINDS FRIDAY NIGHT. SKY COVER INCREASES SATURDAY BUT MOSTLY HIGH THIN CLOUDS UNTIL LATE IN THE DAY. TEMPS IN THE MIXED LAYER WILL BE 12-14C WHICH SUPPORTS MAX SFC TEMPS LOW TO MID 80S. SATURDAY NIGHT-SUNDAY... AS THE SHORTWAVE PHASES WITH THE EASTERN UPPER TROUGH...THE SUPPORTING UPPER JET EXTENDS EAST TOWARD NEW ENGLAND. MEANWHILE WEST TO SOUTHWEST LOW LEVEL WINDS WILL BRING INCREASING HUMIDITY. THIS WILL MEAN INCREASING CLOUDS AND AN INCREASING CHANCE OF SHOWERS/THUNDER OVERNIGHT INTO SUNDAY AS THE RESULTING WARM FRONT APPROACHES. EXPECT DEWPOINTS TO INCREASING DURING THIS TIME AND REACH 65-70. MONDAY-TUESDAY-WEDNESDAY... SURFACE LOW ASSOCIATED WITH THE SHORTWAVE PIVOTS OVER THE GREAT LAKES SUNDAY NIGHT/MONDAY AND SWINGS A COLD FRONT TOWARD THE EAST COAST. AT THIS SAME TIME...THE UPPER TROUGH DEEPENS AND TURNS THE UPPER FLOW OVER THE EAST COAST MORE SOUTH-SOUTHWEST. AS A RESULT OF THIS...THE COLD FRONT WILL SLOW ITS EASTWARD PROGRESS MONDAY AS IT BECOMES PARALLEL TO THE UPPER FLOW. WE WILL BE IN THE WARM SECTOR LEADING THE COLD FRONT MONDAY AND PROBABLY TUESDAY. THIS SHOULD SUPPORT A CHANCE OF SHOWERS/TSTMS EACH DAY...ALTHOUGH LESS CONFIDENCE IN THE AREAL COVERAGE OF CHANCE POPS TUESDAY. LONG RANGE GUIDANCE SUGGESTS DRY WEATHER WEDNESDAY EVEN WITH THE UPPER LOW OVER THE LAKES AND BROAD CYCLONIC FLOW OVER NEW ENGLAND. WE WENT ALONG WITH THIS IDEA FOR NOW...BUT WITH LOW CONFIDENCE.
-- End Changed Discussion --
&& .AVIATION /18Z THURSDAY THROUGH TUESDAY/...
-- Changed Discussion --
FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY NIGHT/...HIGH CONFIDENCE. THIS AFTERNOON THROUGH FRIDAY NIGHT... MAINLY VFR CONDITIONS RIGHT THROUGH FRIDAY NIGHT...OTHER THAN VERY LOCALIZED OVERNIGHT GROUND FOG. THE EXCEPTION WILL BE ACROSS THE CAPE AND PARTICULARLY NANTUCKET...WHERE MVFR CIGS MAY HOLD ON INTO THIS EVENING BEFORE ENOUGH DRY AIR SCOURS THEM OUT. THEN EXPECT VFR CONDITIONS THE REST OF THE TIME IN THESE LOCATIONS AS WELL. KBOS TAF...HIGH CONFIDENCE. SEA BREEZE DIMINISHES THIS EVENING BUT EXPECT IT TO RETURN BY FRIDAY AFTERNOON. KBDL TAF...HIGH CONFIDENCE. OUTLOOK...SATURDAY THROUGH MONDAY...MODERATE CONFIDENCE. SATURDAY...VFR. LOCAL IFR POSSIBLE IN EARLY MORNING FOG/LOW CLOUDS. SATURDAY NIGHT-SUNDAY-MONDAY... VFR BUT WITH AREAS OF MVFR IN SHOWERS/TSTMS.
-- End Changed Discussion --
&& .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. SHORT TERM /THROUGH FRIDAY/...MODERATE CONFIDENCE. WINDS AND SEAS ARE FORECAST TO BE BELOW SMALL CRAFT ADVISORY THRESHOLDS THROUGH FRIDAY. NORTHWEST TO NORTHEAST WINDS ARE FORECAST FOR TODAY...GRADUALLY SHIFTING TO THE SOUTHWEST BY FRIDAY AFTERNOON. LOCAL SEA BREEZES ARE EXPECTED ON FRIDAY. LOCALLY DENSE FOG AT TIMES TODAY AND TONIGHT...ESPECIALLY OVER THE WATERS SOUTHEAST OF MA WITH VISIBILITIES 1 MILE OR LESS AT TIMES. OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE. FRIDAY NIGHT-SATURDAY... LIGHT SOUTHWEST WINDS FRIDAY NIGHT INCREASE ON SATURDAY BUT SHOULD REMAIN BELOW 25 KNOTS. SEAS ALSO BUILD BUT SHOULD REMAIN BELOW 5 FEET. SATURDAY NIGHT-SUNDAY...A WARM FRONT APPROACHES THE WATERS WITH WARMER MORE HUMID AIR AND WITH CLOUDS/SHOWERS/TSTMS. INCREASING SOUTHWEST WINDS WITH GUSTS NEAR 25 KNOTS SUNDAY AFTERNOON AND SEAS BUILD TO 5-6 FEET ON THE EXPOSED WATERS. A SMALL CRAFT ADVISORY MAY BE NEEDED. MONDAY...WARM HUMID AIR OVER THE WATERS WITH SOUTHWEST WINDS GUSTING 20-22 KNOTS. THIS SHOULD KEEP SEAS AT 5-7 FEET ON THE EXPOSED WATERS. THE POTENTIAL FOR SMALL CRAFT ADVISORY WILL CONTINUE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...WTB/GAF NEAR TERM...FRANK SHORT TERM...GAF LONG TERM...WTB AVIATION...FRANK/WTB MARINE...WTB/GAF

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