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 141950 AFDBOX Area Forecast Discussion National Weather Service Taunton MA 350 PM EDT Sat Oct 14 2017 .SYNOPSIS...
-- Changed Discussion --
Showers will move offshore today. Showers, drizzle and fog will occur tonight ahead of approaching warm front. Very warm and humid conditions will occur on Sunday. A sharp cold front will sweep the region Monday behind which it will be breezy as temperatures drop to around freezing. Gradual warm-up through the week, possibly into the weekend, overall dry and quiet.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --
400 PM Update... Inverted trough and area of showers continue to move offshore this afternoon. Clouds continue to erode from the NW to the SE resulting in a significant temperature difference. Fitchburg has warmed to 75F while hear in Taunton it is 65F. Despite clouds continue to erode, believe that since peak heating has passed, temperatures could only warm just a few degrees. Still WAA aloft will help keep temps from truly radiating out during the later afternoon into the early evening hours. Aside from a few updates, the overall forecast remains on track this afternoon. Tonight... Bermuda high pressure will continue to take hold south and east of the region keeping the region in a more southerly flow. Weak inverted trough at the surface will spin offshore by this evening resulting in a dry trend in the forecast. Approaching surface warm front tonight combined with warming 850 mb temps may result in some overrunning precip during the overnight into early Sunday morning. In fact, hi-res guidance continues to indicate come spotty qpf which increases confidence in light precip. Persistent low level flow with higher theta-e values streaming will help increase dewpoints and with overnight temps remaining steady, cloud see fog development. Low confidence on how dense the fog will be but latest NARRE guidance as well as others do show the potential for dense fog across the South Coast, Cape and Islands. Will hold off on issuing a dense fog advisory for now and will let later shifts get another look. Overall fog, drizzle and low clouds will be the story for tonight as moist low-level flow takes hold of the region.
-- End Changed Discussion --
&& .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
-- Changed Discussion --
Sunday... Showers and drizzle will slowly come to an end after daybreak on Sunday as surface warm front push through the area. Behind the front, 850 mb temps warm to 17C and 925 mb LLJ strengthens to near 30-40 kts. If clouds break during the afternoon, and mixing increases up to 850 mb, then temperatures could warm into the low 80s. Aside from warm temperatures, we could see gusts to near 25 MPH or higher if true mixing occurs. Highest gusts will be across the eastern half of the region, which is closer to the strengthen LLJ. Sunday will continue to trend dry, but still cannot rule out a few isolated showers developing across the south coast. Sunday night... Strengthening low pressure system over the Great Lakes will move eastwards towards northern New England by Monday morning. This surface low will drag a cold front through upstate NY and southern New England during the overnight hours. The main story however is the secondary shortwave rounding the trough late Sunday pushing this front through the region during the predawn hours of Monday morning. Ahead of this front, cannot rule out a few isolated showers across the south coast with continue low level moisture and dewpoints near the mid to upper 60s. Overnight lows will remain warm as WAA continues to stream into the region. Some showers will develop along the front, but mid-levels are still on the dry side so do not expect much in the way of heavy rainfall. After midnight, the cold front will begin to approach the region resulting in a surge of southerly winds with gusts near 25 MPH. The front appears to quickly push through around 2-6 AM. Stout CAA behind the front will result in a quick drop in temperatures and a surge of wind. Temperatures could from 60F to 45F within a 3 hour span. BUKFIT soundings show good mixing behind the front with 850 mb LLJ increasing to 50-55 kts. This could result in a quick 35-40 MPH gusts with some higher gusts across the higher elevations right behind the front. This could result in down tree and wires during the overnight hours. There is the potential for wind headlines but will let later shifts take another look.
-- End Changed Discussion --
&& .LONG TERM /MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
*/ Highlights... - Sharp cold front Monday, turning cold - Gradual warm-up through the week, possibly into the weekend - Perhaps a pattern change into late October, more active, cooler */ Overview... Struggles with the synoptic pattern interpretation for the rest of October. Presently the preferred region of deeper vortex development lies across the state of Alaska. Energy earlier this week has become displaced and is now shooting E over S Canada / N CONUS, amplifying the mid-level flow, creating a see-saw pattern of airmasses through the week into the following weekend over the NE CONUS via trailing influences with a shot of cooler air Monday through as late as Friday with a potentially considerable warm-up thereafter through the weekend (dependence upon the influence of an offshore sub- tropical low). This as a deeper vortex re-emerges over Alaska shearing and cutting off downstream energy over the SW CONUS. Hereafter the synoptic set-up is a bit tricky to diagnose. A dynamic shift is plausible as indicated by the change in atmospheric tele- connections. Perhaps the near-tropopause polar vortex shifting away from Alaska towards N Asia, or rather the warmer tropical pineapple connection into the W CONUS as indicated via a rather good consensus forecast of the MJO going from a moderate to strong phase 4 through phase 5 into phase 6 indicating tropical activity along the ITCZ is shifting gradually W. Subsequently we could see a reversion in the mid- latitude pattern over the E CONUS from one of preferred ridging to that of deeper troughing towards late October. Too early to say but at least for the foreseeable future expect seasonable conditions and generally quiet weather. Will hit the specifics in the details below. */ Discussion... Monday into Monday night... Sweeping sharp cold front early. Chance to likely PoPs. Pressure rises behind the front along with cold air advection allow for deeper boundary layer mixing, likely gusty NW winds immediately in wake at least to 30 mph, possibly as high as 40 mph. Could be set with a non-diurnal trend in temperatures. Highs just prior to cold frontal passage with temperatures steady or falling with passage during the day. Dropping out overnight with continued cold air advection, lows falling into the 30s, requiring frost / freeze head- lines, more likely across N/W MA and CT with light NW winds. Else- where, breezy winds would prevent frost development however not so much freezing conditions. Tuesday through Wednesday... Gradual warm-up. Westerly interior winds as high pressure builds S/E of our region. Temperatures slowly climb day by day. Dry. Quiet. Thursday into Friday... Dry cold frontal passage. A subtle change in the airmass with winds becoming more W/NW instead of SW. However the warm-up continues. Temperatures rebounding to seasonable values for mid to late October in the 60s and 70s for highs. Weekend into early next week... Some question as to the magnitude and position of high pressure up against a sub-tropical low offshore. From the consensus of the model guidance the warm-up continues with a westerly flow, however with a shift to the W we could be under more E flow associated with the off- shore low. Will keep with a seasonable pattern in the 60s and 70s with westerly winds.
-- End Changed Discussion --
&& .AVIATION /20Z SATURDAY THROUGH THURSDAY/...
-- Changed Discussion --
Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Short Term /through Sunday Night/...Moderate confidence. Rest of the day...Improving to VFR this afternoon with MVFR/IFR conditions lingering for the Cape and Islands. Tonight...Any VFR/MVFR cigs/vsbys will drop after midnight to IFR/LIFR in light showers, fog and drizzle. Tomorrow...Conditions will slowly improve from west to east during the morning hours. Still a few spotty showers are possible for the southern half of the area. Mainly VFR w/ occasional MVFR cigs. Southerly winds will be on the increase during the day with gusts near 25 kts. Tomorrow Night...Mix of VFR/MVFR conditions to start. Stout cold front will push through switching southerly winds to the west. Strong gusty winds will develop behind the front with gusts near 30-35 kts into early Monday morning. KBOS TAF...Moderate confidence in TAF. VFR cigs/vsbys today will drop to IFR for the overnight hours. KBDL TAF...Moderate confidence in TAF. VFR with sct MVFR cigs this afternoon. IFR conditions in low CIGS/fog by around midnight. Outlook /Monday through Thursday/...Moderate confidence. Monday... Initially MVFR / low-end VFR mix with -SHRA, clearing and lifting with SCT low-end VFR becoming SKC. Initial SW winds reverting NW and immediately breezy with gusts up around 30 kts possible. Tuesday through Thursday... VFR. W winds. Quiet.
-- 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 Sunday Night/... Tonight...Moderate confidence. Southerly flow will low vsbys in fog, drizzle and sct showers. Seas around 5 feet for the outer waters. Sunday...Moderate confidence. Passing warm front will increase southerly winds to 25-30 kts by the afternoon. Seas will being to strengthen, SCA will continue for all waters. Sunday night...Moderate confidence. Increasing southerly LLJ will aid in wind gusts to near 30 kts. Stout cold front will approach the waters switching the winds to a more westerly direction. Low prob for gale force winds for just an hour or two behind the front. Outlook /Monday through Thursday/...Moderate confidence. Sharp cold front sweeping the waters early Monday. Initial SW winds will turn immediately NW with passage and become blustery. Can`t rule out near-gale force gusts immediately behind the front, then diminishing. Seas already 5 to 7 feet at the start of the forecast period then diminishing through Tuesday. Quiet boating weather under high pressure the rest of the period.
-- End Changed Discussion --
&& .CLIMATE... Min temperatures Saturday night could be rather close the record maximum low temperatures for our four long term climate sites. October 15 Record maximum low temperatures Boston 64/1954 Worcester 64/1954 Hartford 63/2014 Providence 63/2014 && .BOX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 1 PM Sunday to 9 AM EDT Monday for ANZ231>234. Small Craft Advisory from 2 PM Sunday to 9 AM EDT Monday for ANZ230-236-251. Small Craft Advisory from 11 AM Sunday to 9 AM EDT Monday for ANZ235-237-250. Small Craft Advisory until 9 AM EDT Monday for ANZ254>256.
-- End Changed Discussion --
&& $$ SYNOPSIS...Dunten/Sipprell NEAR TERM...Dunten SHORT TERM...Dunten LONG TERM...Sipprell AVIATION...Dunten/Sipprell MARINE...Dunten/Sipprell CLIMATE...Staff

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