Area Forecast Discussion
Issued by NWS Boston, MA

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000 FXUS61 KBOX 070233 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 933 PM EST Mon Feb 6 2023 .SYNOPSIS... High pressure builds in from the west late tonight and Tuesday with colder conditions. Scattered rain/snow showers Tuesday night with a frontal system, then turning milder again through the end of the week with temperatures well above normal, especially Friday. Another frontal system will bring rain Thursday into Thursday night followed by drier and unseasonably mild weather Friday. Temperatures trend cooler along with unsettled conditions into the weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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9:30 PM Update: Both sky cover and winds have diminished more quickly than forecast as low pressure pulls to our north and east. Some lower clouds hang on across the Cape and Islands given their proximity to the low compared to the rest of the region. Minor adjustments were made to the timing of the forecast, but overall, the forecast remains in good shape. Given that winds have diminished rather quickly this evening, many of our Gale Warnings were converted to Small Craft advisories. The remaining Gales will be converted as they expire. Update 650 PM: Clouds continue to shift east and away from southern New England as a powerful surface low moves NE towards Nova Scotia. Gusts continue to come in from the N/NE generally around 30 to 40 mph along the coast. As the low shifts away, winds will begin to ease. No significant changes were made as the forecast continues to remain on track. Only made small changes to bring the forecast in line with the latest observations. Previous discussion below. Tonight A deep low pressure system off the southeast coast of southern New England continues east over The Atlantic maritimes overnight. As this system pulls away the pressure gradient driving gusty north/northeast wind gusts this evening will weaken substantially. This will eventually lead to the gusty north/northeast winds diminishing overnight. A drier air mass filters in from the west and results in skies clearing across most of interior southern New England. Clouds may linger over the coastal areas. As the atmosphere decouples after midnight we should see fairly efficient radiational cooling that will support chilly overnight lows in the upper teens to low 20s across the north and western areas. Along the coastal plain, some cloud cover and boundary layer mixing will support more mild overnight low temperatures ranging from the mid 20s to the low 30s over The Cape and Islands.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... Tomorrow Northeast winds continue for the first half of the day tomorrow. This will support cooler temperatures during the afternoon with highs struggling to escape the 30s. As high pressure shifts east of the region during the mid-afternoon hours, southerly flow will take over and support increasing cloud cover ahead of an approaching cold front. Tomorrow Night An upper-level short-wave trough propagates over southern New England tomorrow night. This will drag a surface cold front through the region with a period of scattered showers. The PType associated with these showers remains a forecast challenge, but as of now model soundings suggest a period of snow will be likely for most of the locations that experience precipitation after 7 pm. The high terrain of The Berkshires/Worcester hills will be the areas where wintry precipitation will be most likely, while the lower elevations/coastal plain are more likely to see rain. Also can`t rule the possibility of periods of freezing rain/sleet as model soundings reveal a shallow melting layer as this front rolls through the region. Any snow/ice accumulations will be limited to dusting/trace amounts, therefore impacts from any wintry precip will be little to none. Expect these showers to be clear of the region by day break on Wednesday. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Highlights... * Warming trend Wednesday into Friday, near record high temperatures possible on Friday, then trending cooler for the weekend. * Unsettled pattern Thursday into Friday and then possibly into this upcoming weekend. Temperatures: Ready or not, another mild stretch of weather is around the corner starting Wednesday. Looking at the mid-level, heights are increasing Wednesday, transitioning towards an amplified mid-level ridge Thursday and Friday. Much of the deterministic and ensemble guidance continues to support well above normal temperatures Wednesday, Thursday, and Friday... especially Friday. Mid to upper 40s would be pretty common Wednesday and Thursday, with lower 40s in the higher terrain. As for Friday, 850mb temperatures over southern New England range from +7C to +10C! May not sound impressive, but that is a +12C to +16C departure from normal. Friday appears to be the warmest day of this week with highs potentially in the middle and upper 50s. These temperatures could be under done by a few degrees if we breakout into more sunshine. That said, afternoon high temperatures will be close to the daily record high for Friday. Record high for Boston is 60F set in 1990, Worcester is 55F set in 1909, Providence is 58F set in 1909, and Hartford is 55F set in 1909. As a reminder, normal highs for early February are mid to upper 30s and lows upper teens and low 20s. Precipitation: Those yearning for winter conditions will not appreciate the forecast for the second-half of the week. A few showers do linger Wednesday morning in the wake of a passing cold front. But, high pressure settles in for the rest of Wednesday and first-half of Thursday. Forecast soundings point to a fairly dry atmosphere along with deterministic and ensemble forecasts. PWATs are generally less than two tenths of an inch through Wednesday night, not expecting any real weather during this period. Sky cover remains mainly clear Wednesday through Wednesday night, increasing clouds by Thursday morning. Weather becomes unsettled Thursday into Friday as a vertically stacked low pressure system travels through the Great Lakes and moves northeast into southern Canada. Given how far inland the system is, once again to be a mainly rain event. Isolated snow or wintry mix are possible Thursday afternoon as a frontal boundary lifts north. Areal coverage at this time would be limited to the higher elevation of northern and western Massachusetts. For what it is worth, forecast sounding at KORE [Orange, MA] does have an hour or two of -SN before changing over. Lower confidence in coverage of showers on Friday, deterministic guidance would support the precipitation ending in the morning... But the ensembles would continue it. Given lower confidence during the day Friday, left POPs at chance. Looking ahead at the upcoming weekend, guidance would like to place a surface low off the coast of southern New England. GFS running a bit on the warmer side, versus a colder Euro solution. Pounds of time, so stay tuned! && .AVIATION /03Z TUESDAY THROUGH SATURDAY/...
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Forecaster Confidence Levels: Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent. 00Z update... Tonight... High confidence. Mainly VFR, but areas of MVFR cigs may develop over Cape/Islands. N wind gusts 25 kt near the coast but up to 35 kt Cape/Islands. Winds diminishing overnight. Tuesday... High confidence. VFR, but may see some MVFR cigs Cape/Islands in the morning. N wind gusts to 25 kt Cape/Islands diminishing by mid morning. Winds turn southerly in the afternoon, increasing late in the day. Tuesday Night...Moderate Confidence. Rain/snow showers move through the region with a cold front tomorrow night.This may bring periods of MVFR ceilings over the western areas during the frontal passage, but otherwise VFR conditions should prevail. South winds from 10 to 20 knots becoming westerly by Wednesday morning. KBOS Terminal...High Confidence in TAF. KBDL Terminal...High Confidence in TAF. Outlook /Wednesday through Saturday/... Thursday: Mainly VFR, with local IFR possible. Breezy. RA likely. Thursday Night: Mainly VFR, with areas IFR possible. Windy with gusts up to 30 kt. RA likely, patchy BR. Friday: VFR. Breezy. Chance RA. Friday Night: Mainly VFR, with local MVFR possible. Breezy. Chance RA. Saturday: Mainly VFR, with local IFR possible. Windy with local gusts up to 30 kt. Chance RA. Saturday Night: VFR. Windy with gusts up to 30 kt. Sunday: Windy with 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. Marine Tonight through Tuesday night Gale force wind gusts gradually diminish during the hours following midnight. Northeast winds continue to weaken throughout the day tomorrow as high pressure builds over the region. A cold front will push through the region late tomorrow night with scattered showers and 20 to 30 knot wind gusts out of the west. Outlook /Wednesday through Saturday/... Thursday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain. Thursday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Rain, patchy fog. Friday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Chance of rain. Friday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Chance of rain, patchy fog. Saturday: Moderate risk for Small Craft Advisory winds with areas of gusts up to 30 kt. Areas of rough seas. Chance of rain. Saturday Night: Moderate risk for gale force winds with gusts up to 35 kt. Rough seas up to 9 ft. Slight chance of rain. Sunday: Low risk for gale force winds with gusts up to 35 kt. Areas of rough seas.
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&& .BOX WATCHES/WARNINGS/ADVISORIES...
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CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 1 PM EST Tuesday for ANZ230-233>237. Small Craft Advisory until 7 PM EST Tuesday for ANZ231-232-251. Gale Warning until 5 AM EST Tuesday for ANZ250-254-255. Gale Warning until 3 AM EST Tuesday for ANZ256.
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&& $$ SYNOPSIS...Gaucher/RM NEAR TERM...Gaucher/RM/KS SHORT TERM...RM LONG TERM...Gaucher AVIATION...Gaucher/RM MARINE...Gaucher/RM

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