Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 161925 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 325 PM EDT Sat Mar 16 2024 .SYNOPSIS...
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A cold front will bring a brief round of showers early tomorrow morning along with gusty winds into tomorrow afternoon. Mainly dry Sunday afternoon and evening with mild temperatures. Temperatures trending near to cooler than seasonable for much of the upcoming week. Isolated showers possible Monday through Thursday along with gusty winds. Drier on Friday.
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&& .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
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Vertically stacked upper level trough and surface low over the Great Lakes brings a warm front through the region tonight followed by a cold front tomorrow morning. The warm frontal passage wont include much more then just increased cloud cover due to very dry mid level air above 700mb. Winds begin to increase out of the SW overnight as a 925mb LLJ strengthens as it moves east. expecting wind gusts of 20- 30mph inland and 25-35mph near the coasts. Overnight lows stay on the milder side due to cloud cover and gusty winds only dropping into the upper 30s to low 40s.
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&& .SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
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Tomorrow A cold frontal passage will bring a period of light rain showers early tomorrow morning. Showers should enter from the NW after 5am and move offshore to the east by noon. With weak forcing aloft, quick moving front, and PWATS only around 0.5-0.6 inches, QPF amounts will remain very light around 1/10th of an inch with isolated areas of a quarter inch. Behind the front, skies begin to quickly clear. This should help high temperatures jump into the upper 50s to low 60s before surface winds turn NW and start advecting in colder air. Winds remain gusty at 20-30mph out of the SW initially, but turning WNW in the afternoon. Tomorrow night Upper level trough and cold pool begin to work in. Winds decrease a bit overnight as the boundary layer tries to decouple, however, cold air advection will promote mixing overnight and winds could remain gusty at 10-20mph. Even with gusty winds, overnight lows will drop near or below freezing away from the immediate coastlines with clear skies and cold air advection.
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&& .LONG TERM /MONDAY THROUGH SATURDAY/...
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Key Points... * Temperatures seasonable this week with highs in the 40s. * Spotty showers possible Mon/Tue and more widespread on Wednesday, lingering into Thursday; not a washout. * Dry on Friday before another system next weekend. The bulk of this week will be influenced mainly by a broad mid/upper level trough which lingers over the northcentral/northeast U.S. Several disturbances will round the base of the trough through the week providing enhanced lift and rain chances along with it before more zonal flow returns briefly to end the week. Temperatures will dip down to normal or just below thanks to this trough, with highs staying in the 40s. Given our close proximity to a series of lows just to our north and east much of the week, winds will remain gusty each day. This week won`t be a washout, with only slight chances of rain or graupel showers Monday and Tuesday thanks mostly to the cold pool aloft with 500 mb temps in the -20 to -30C range. This, combined with surface temps in the 40s to near 50 will lead to diurnal clouds and spotty showers. We`re also getting into that season where steep lapse rates like these (6-8c/km) may lead to graupel showers. Best chance between Monday and Tuesday looks to be on Tuesday. By Wednesday we`ll see an expansion in shower coverage as a more significant shortwave disturbance rounds the broader trough and crosses New England with a surface reflection to our north. Dynamics aren`t super impressive nor is the moisture (PWATs near 0.3") so not expecting to see rain all day or everywhere, but showers will be around potentially into Thursday. Not until Friday do we finally get some rising heights and surface high pressure which will keep things dry ahead of what looks to be our next widespread/heavier rainfall system next weekend. Still a large spread in the ensemble guidance at this timeframe but odds of widespread precip are increasing.
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&& .AVIATION /19Z SATURDAY THROUGH THURSDAY/...
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Forecast Confidence Levels: Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Rest of Today...High confidence. Mainly VFR with isolated pockets of high end MVFR due to a strato cumulus field that formed. Strato cu will diminish this evening. Winds will slowly increase out of the SW today. Tonight...Moderate Confidence. VFR to start tonight with SW winds. An area of IFR status may form overnight across RI and SE MA. Otherwise, MVFR CIGS work in ahead of a cold front. light rain showers move NW to SE tonight beginning around 08-10z in the west and 09-11z in the east. Tomorrow...High Confidence MVFR/IFR with light rain showers ahead of the cold front through 12-14z, lagging until 14-16z for the Cape and Islands. Behind the cold front, quick improvements to VFR with winds shifting from SW to NW. Winds remain gusty all day at 20-30 knots. Sunday Night...High Confidence VFR. Light west winds. KBOS TAF...High confidence in the overall TAF. Sea breeze continues this afternoon kicking out around 22-23z. VFR this evening. MVFR late tonight with a low chance at IFR. Light rain showers are possible from 10-13z tomorrow. VFR behind the cold front with gusty SW winds turning NW by the afternoon. KBDL TAF...High confidence in TAF. VFR today. MVFR tonight with light rain showers between 09-11z VFR tomorrow with gusty SW winds turning NW by the afternoon. Outlook /Monday through Thursday/... Monday through Monday Night: VFR. Breezy. Tuesday: VFR. Windy with gusts up to 30 kt. Slight chance RA. Tuesday Night: VFR. Windy with local gusts up to 30 kt. Wednesday: VFR. Breezy. Slight chance RA. Wednesday Night: VFR. Breezy. Thursday: VFR. Windy with local gusts up to 30 kt.
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&& .MARINE...
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Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. Tonight... High Confidence Winds slowly increase out of the SW gusting 20-30 knots. Seas increase to 3-5 feet. Tomorrow... High Confidence Periods of light rain showers starting around sunrise and lasting through about noon. Winds turn WNW but remain gusty at 20-30 knots. Seas increase to 4-7 feet. Tomorrow night... High Confidence Decreasing winds overnight but still gusting 15-20 knots out of the WNW. Seas decrease to 3-5 feet. Outlook /Monday through Thursday/... Monday through Monday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Tuesday through Tuesday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Wednesday: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain. Wednesday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of seas approaching 5 ft. Thursday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from 5 AM to 11 AM EDT Sunday for ANZ230- 236. Small Craft Advisory from 2 AM to 2 PM EDT Sunday for ANZ231- 251. Small Craft Advisory from midnight tonight to 5 PM EDT Sunday for ANZ232>235-237. Small Craft Advisory from 10 PM this evening to 2 AM EDT Monday for ANZ250. Small Craft Advisory from 10 PM this evening to 8 AM EDT Monday for ANZ254>256.
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&& $$ SYNOPSIS...BW/KP NEAR TERM...KP SHORT TERM...KP LONG TERM...BW AVIATION...BW/KP MARINE...BW/KP

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