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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBOX 130802 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 402 AM EDT Fri Oct 13 2017 .SYNOPSIS...
-- Changed Discussion --
Strong high pressure over the Canadian Maritimes provides dry and seasonably cool weather today. Return flow around the high Saturday gives way to a warming trend along with increasing humidity into Sunday. A warm front will bring scattered showers to the area Saturday into Sunday morning, followed by a brief dry period late Sunday morning into the afternoon. Rain chances increase again Sunday evening and overnight as a cold front sweeps across the area. A few gusty showers are possible. Behind the front, dry and cooler weather much of next week.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/... 145 AM Update... Mainly clear skies continue through 05Z across most of the region. Still noting some patchy ocean effect low clouds across the mid and lower Cape and S Mass coast as well as on Martha`s Vineyard and Block Island with E-NE winds in place pushing low level moisture across the cooler air. Also seeing patchy fog across interior E Mass at times from KOWD-KTAN. Temps have fallen to the lower-mid 30s across interior E Mass from interior Cape Ann through the Route 128 beltway into interior SE Mass. So far, 34 degrees at both KTAN and KOWD, 35 at KORE and 37 at KBVY and KBED. With light/variable or calm winds, temps will probably fall a couple more degrees through the remainder of the pre dawn hours as high pressure ridge remains across interior southern New England. Will also see patchy frost through 12Z or so across the same normally prone inland areas. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... Today... High pressure starts from New Brunswick and Maine across the region, then the high slowly moves eastward during the afternoon. Model soundings indicate a subsidence inversion lasting thru the day. There should be some increase in mid to high deck clouds during the day. Then with the winds becoming more SE, we start to see an increase in low level moisture that would be trapped under the inversion. So anticipating sunny skies to start, then transitioning to partly/mostly sunny in the afternoon. Dry conditions thru the day. Highs will range from 60-65 at most locations, though could be a bit cooler across the higher inland terrain. Tonight... Increasing cloudiness expected as southern New England is positioned for a return flow/warm air advection pattern. An increase in moisture is expected as lower level winds shift to the S/SW, though models differ on the amount of moisture. NAM and GFS have backed off somewhat on shower potential, with just a low/slight chance pop for light QPF. Will continue to follow a model blend which produces slight chance pops Fri night. Overnight lows will be on the mild side thanks to increasing surface dew points and increasing cloud cover. Temps drop around 50 to the mid 50s. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
-- Changed Discussion --
Highlights... * Much warmer than normal and humid Sat night/Sunday * Scattered showers Sat into Sun morning, then again Sun night * Dry weather much of next week and chilly Mon night/Tuesday Saturday night... Anomalous 591 dam subtropical ridge over the southeast states builds into the Mid Atlc region and results in a warm front moving across southern New England. This boundary and associated moisture plume of PWATs +2 standard deviations above normal will result in a chance of showers. Very mild night for mid Oct given dew pts in the low to mid 60s! This will also yield a risk for patchy dense fog. Sunday... Chance of morning showers as warm front lifts northward across the area. Warm sector overspreads the area by late morning/early afternoon with 925 mb temps surging to +17C to +18C at 925 mb! This will support highs easily 75-80 away from the south coast with a low prob of a few interior locations getting into the low 80s, which will approach new record highs for the day. Quite anomalous when you consider the normal high temp for mid Oct is 60-65. After warm front exits late morning a period of dry weather is expected in the warm sector. It will become windy as 991 cyclone exits the northern Great lakes and intensifies to a sub 980 low as it tracks across southern Quebec during the day Sunday. This strengthening pres gradient combined with steepening low level lapse rates in the warm sector will support southwest wind gusts up to 40-45 mph, which may be strong enough for isolated wind damage given fully leaved trees. Greatest risk appears eastern MA given location of low level jet. Sunday night... Strong low level convergence along approaching cold front and robust upper level jet streak with RRQ over southern New England. This will support a deep layer of ascent accompanied by adequate deep layer moisture. This setup may provide a broken line of low top convection along and ahead of approaching cold front. Given strong wind fields a few of the heavier showers may produce gusty winds. Instability appears to be lacking but with dew pts in the mid 60s will have to monitor instability trends on later model runs. If instability is greater than what models are simulating this could be a sneaky low top convective event. Fropa occurs later Sun night with much drier/less humid post frontal airmass ovespreading the region 06z-12z Monday. Next Week... Dry and seasonably cool Monday behind initial cold front late Sun night/early Mon morning. Coolest air arrives Mon ngt/Tue morning with secondary/trailing short wave trough. Guidance has 850 mb temps cooling off to about -2C across New England. So slightly cooler than normal Mon ngt into Tue along with patchy frost possible as MOS guid offers lows in the 30s, some upper 20s possible. GFS and EC ensembles lower 850 temps to about -3C 12z Tue with deterministic guid as cool as -6C. Nonetheless a cool shot of air Mon ngt/Tue. Ensembles and deterministic guidance both indicate northern stream reloads middle of next week with new jet energy diving into the northeast mean trough. This will support a reinforcing shot of seasonably cool airmass. Regarding precip, this looks to be a rather dry pattern.
-- End Changed Discussion --
&& .AVIATION /08Z FRIDAY 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 Saturday/...High confidence. Through 12Z...VFR. Light E-NE or calm winds. Patchy fog will develop, with brief MVFR-IFR CIGS/VSBYS in some of the locally prone inland areas, mainly portions of the CT valley and interior E Mass. Also patchy MVFR CIGS at times along portions of the mid and lower Cape, KEWB, KMVY and KBID. Today...Mainly VFR. Local MVFR VSBYS in patchy fog through 14Z across interior E Mass and parts of the CT valley. E wind gusts up to around 15 kt along immediate E coast and on the islands. May see MVFR CIGS move into S coastal areas around 22Z. Tonight and Saturday...Mainly VFR. CIGS lowering to MVFR to local IFR across central and western areas around or after midnight with MVFR VSBYS in patchy fog. Chance of showers central and western areas after midnight. KBOS TAF...High confidence in TAF. Mainly E winds around 10 kt through most of today, then becoming light SE-S this evening. Low risk of MVFR CIGS at times from around 08Z into the Saturday morning push. KBDL TAF...High confidence in TAF. May see brief patchy fog through 12Z-13Z with local MVFR VSBYS possible. MVFR CIGS after 04Z and MVFR VSBYS at times in patchy fog. Chance of showers around or after midnight. Outlook /Saturday Night through Tuesday/... Sat night/Sunday morning...MVFR with IFR possible in the higher terrain. Scattered showers and patchy fog. Moderate confidence with some uncertainty on areal coverage of IFR. Sunday afternoon...MVFR and VFR. Mainly dry but gusty SW winds up to 30 kt, possibly higher. High confidence. Sunday night...MVFR with scattered showers, a few gusty showers possible. SW winds up to 30 kt, possibly slightly higher. Moderate confidence with some uncertainty on areal coverage and intensity of showers. Mon and Tue...VFR and dry. High confidence.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Saturday/... Overnight and Friday... Winds and seas remain at or above small craft criteria across the open waters. Expect gusts up to 25 kt mainly on the southern waters, but seas remain around 5-7 ft through the remainder of the night though may gradually subside on the eastern outer waters after 06Z or so. While the wind gusts diminish Friday, seas of 4 to 6 feet will remain along the southern outer waters. Small crafts continue for most of the waters. Tonight... High pressure departs. Visibility may lower in patchy fog and spotty showers. S winds around 10 kts. Outlook /Saturday night through Tuesday/...high confidence except some uncertainty how strong southwest winds become Sun afternoon and evening. Saturday night...poor vsbys in areas of showers/drizzle and fog. Sunday...poor vsbys in areas of morning showers/drizzle and fog, improving by midday. SW winds become gusty especially near shore with gusts up to 30 kt, possibly higher. Cold frontal passage Sunday night. Mon and Tue...cold front moves offshore early Mon followed by dry weather and good vsby.
-- End Changed Discussion --
&& .BOX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...Frost Advisory until 8 AM EDT this morning for CTZ002>004. MA...Frost Advisory until 8 AM EDT this morning for MAZ002>006- 008>014-017-018-026. RI...None. MARINE...Small Craft Advisory until 7 AM EDT this morning for ANZ235- 237. Small Craft Advisory until 1 PM EDT this afternoon for ANZ254. Small Craft Advisory until 4 PM EDT this afternoon for ANZ255. Small Craft Advisory until 11 AM EDT Saturday for ANZ256.
-- End Changed Discussion --
&& $$ SYNOPSIS...Nocera/EVT NEAR TERM...EVT SHORT TERM...EVT LONG TERM...Nocera AVIATION...Nocera/EVT MARINE...Nocera/EVT

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