223
FXUS61 KBOX 040705
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
305 AM EDT SAT APR 4 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES; FORECAST REMAINS ON TRACK.
KEY MESSAGES
- AFTER MILD WEATHER FRIDAY, ANOTHER BACKDOOR FRONT BRINGS A
RETURN TO CHILLY WEATHER SATURDAY AFTERNOON, ESPECIALLY
EASTERN MA.
- SHOWERS SAT NIGHT AND SUNDAY, MILDER WITH HIGHS IN THE UPPER
50S AND LOWER 60S.
- COULD SEE A FEW RAIN/SNOW SHOWERS MONDAY NIGHT/ TUESDAY
MORNING,BUT OTHERWISE EXPECTING COOLER TEMPERATURES AND DRY
WEATHER FOR A GOOD PORTION OF NEXT WEEK.
- SECOND HALF OF NEXT WEEK LOOKS MAINLY DRY WITH TEMPERATURES ON
THE RISE.
DISCUSSION
KEY MESSAGE 1...AFTER MILD WEATHER FRIDAY, ANOTHER BACKDOOR
FRONT BRINGS A RETURN TO CHILLY WEATHER SATURDAY AFTERNOON.
MILD DURING THE PREDAWN HOURS OF SATURDAY ACROSS SNE, WITH
PREFRONTAL AIRMASS AND DEW PTS IN THE UPPER 40S AND LOWER 50S
ACROSS THE REGION. THIS MOIST AIRMASS (BY EARLY APRIL
STANDARDS), COURTESY OF A MODEST LOW LEVEL PREFRONTAL SOUTHWEST
JET, IS THE CULPRIT FOR THE LOW CLOUDS, FOG AND SPOTTY DRIZZLE
ALONG THE SOUTH COAST. AS A COLD FRONT APPROACHES FROM THE NW,
SURFACE WINDS OVER SNE WILL VEER TO THE WNW TOWARD DAYBREAK,
SHUNTING THIS LOW LEVEL MOISTURE OFFSHORE AND GIVING WAY TO
CLEARING/IMPROVING CONDITIONS ALONG THE SOUTH COAST TOWARD
SUNRISE.
AS NORTHERN STREAM JET ENERGY STREAMS ACROSS THE MARITIMES THIS
MORNING, ITS CORRESPONDING SURFACE BOUNDARY WILL TRAVERSE
ACROSS SNE IN THE FORM OF A BACKDOOR FRONT, FROM EAST TO WEST.
HENCE, WARMEST PART OF THE DAY WILL BE THIS MORNING, ALONG WITH
SUNSHINE THRU HIGH CLOUDS, WARMING TEMPS THROUGH THE 50S AND
60S. THEN FOLLOWED BY A NOTICEABLE TEMPERATURE DROP THIS
AFTERNOON FROM EAST TO WEST, AS WINDS SHIFT FROM THE NORTH INTO
THE EAST WITH THE FROPA. THIS WIND SHIFT WILL BE ABRUPT, WITH
GUSTS UP TO 30 MPH FROM THE ENE! THIS COLD AIR IS EVIDENT BY A
POCKET OF -2C TEMPS AT 925 MB ADVECTING DOWN THE COAST OF ME &
NH THIS MORNING, THEN INTO NE MA THIS AFTERNOON. THIS CHILLY
AIRMASS WILL BE ENHANCED BY STREAMING ACROSS OCEAN TEMPS IN THE
LOW TO MID 40S. AT THE SURFACE, THIS WILL TRANSLATE TO A VERY
LARGE TEMP DIFFERENCE ACROSS SNE THIS AFTERNOON, WITH HIGHS WELL
INTO THE 60S ACROSS WESTERN MA/CT, WHILE TEMPS FALL INTO THE
UPPER 30S AND LOWER 40S ACROSS EASTERN MA, INCLUDING BOSTON AND
CAPE COD.
KEY MESSAGE 2...SHOWERS SATURDAY NIGHT INTO SUNDAY, BUT TURNING
MILD SUNDAY, WITH HIGHS IN THE UPPER 50S AND LOWER 60S.
SATURDAY NIGHT...1035 MB SURFACE HIGH OVER THE MARITIMES,
COMBINED WITH THE BACKDOOR FRONT SOUTH OF NEW ENGLAND LIFTING
NORTH AS WARM FRONT, WILL SET THE STAGE FOR OVERRUNNING PRECIP
IN THE FORM OF SPOTTY LIGHT RAIN/DRIZZLE. CHILLY WITH LOWS IN
THE 30S, THEN TEMPS RISING OVERNIGHT INTO THE 40S AS WARM SECTOR
APPROACHES FROM THE SOUTH. GIVEN THE EASTERLY UPSLOPE FLOW UP,
THE EASTERN SLOPES OF THE BERKS MAY EXPERIENCE TEMPS AT OR BELOW
FREEZING. HENCE, SOME SPOTTY LIGHT FREEZING DRIZZLE CAN'T BE
COMPLETELY RULED OUT. HOWEVER, GIVEN MARGINAL TEMPS AND CONFINED
TO ELEVATION AOA 500 FT, LITTLE IF ANY IMPACT EXPECTED.
SUNDAY...LOW PRESSURE OVER THE GREAT LAKES EXITS INTO ONTARIO,
WITH ITS TRAILING COLD FRONT SWEEPING ACROSS SNE. MODEST JET
DYNAMICS COUPLED WITH AN AMPLE MOISTURE PLUME (PWATS 1.2-1.4
INCHES) WILL SUPPORT WIDESPREAD SHOWERS SUNDAY. ALTHOUGH, GIVEN
HOW PROGRESSIVE THIS SYSTEM IS, EXPECTING MODEST RAINFALL TOTALS
ON THE ORDER OF 0.2 TO 0.4 TENTHS OF AN INCH, WHICH IS
SUPPORTED BY BOTH DETERMINISTIC AND ENSEMBLE DATASETS. HENCE,
BENEFICIAL RAINS BUT FLOODING IS NOT EXPECTED. DESPITE THE
WIDESPREAD SHOWERS, ITS A MILD AIRMASS WITH DEW PTS IN THE 50S.
THEREFORE, NOT A CHILLY DAY WITH STRONG LOW LEVEL WAA PROVIDING
HIGHS IN THE UPPER 50S TO LOWER 60S. IT WILL BECOME BREEZY OVER
RI AND EASTERN MA GIVEN THE STRENGTHENING SOUTHWEST JET.
KEY MESSAGE 3...COULD SEE A FEW RAIN/SNOW SHOWERS MONDAY NIGHT/
TUESDAY MORNING, BUT OTHERWISE EXPECTING COOLER TEMPERATURES
AND DRY WEATHER FOR A GOOD PORTION OF NEXT WEEK.
BOTH ENSEMBLE AND DETERMINISTIC GUIDANCE CONTINUE TO BE IN GOOD
AGREEMENT THAT AN UPPER-LEVEL TROUGH PUSHES ACROSS THE GREAT
LAKES AND INTO NEW ENGLAND NEXT WEEK, LEADING TO MOSTLY DRY
WEATHER BUT COOLER TEMPERATURES. ENSEMBLE GUIDANCE IS INDICATING
850MB TEMPERATURES COULD GET TO BELOW -5C AND 500MB
TEMPERATURES BELOW - 30C TUESDAY AS A SHORTWAVE MOVES THROUGH,
WHICH WOULD SUPPORT SNOW SHOWERS DEVELOPING AND MIXING IN WITH
RAIN SHOWERS. GIVEN THAT SURFACE TEMPERATURES WILL REMAIN AT
LEAST IN THE MID 40S, NOT EXPECTING ANY ROAD OR TRAVEL IMPACTS.
OTHERWISE, DRY WEATHER WITH HIGH TEMPS MAINLY IN THE MIDDLE 40S
TO THE LOWER 50S AND OVERNIGHT TEMPERATURES RANGING FROM THE MID
20S TO MID 30S THROUGH WEDNESDAY NIGHT.
KEY MESSAGE 4...SECOND HALF OF NEXT WEEK LOOKS MAINLY DRY WITH
TEMPERATURES ON THE RISE.
A LARGE HIGH PRESSURE SYSTEM MOVES INTO THE MID-ATLANTIC REGION
BY THE SECOND HALF OF NEXT WEEK, BRINGING PREDOMINANTLY
SOUTHWESTERLY FLOW BACK TO SOUTHERN NEW ENGLAND. THE WARMER
AIRMASS ADVECTING INTO THE REGION WILL ALLOW TEMPERATURES TO
RECOVER BACK INTO THE 50S, LIKELY THE 60S, BY THE END OF THE
WEEK. EXPECTING CONDITIONS TO REMAIN MOSTLY DRY.
AVIATION /07Z SATURDAY THROUGH WEDNESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z UPDATE...
HIGH CONFIDENCE IN FORECAST TRENDS, ALTHOUGH, SOME UNCERTAINTY
ON EXACT TIMING OF DETAILS.
SATURDAY...ANY IFR CIGS AT 06Z ACROSS SOUTHERN RI/MA, WILL EXIT
OFFSHORE AND TRANSITION TO VFR CONDITIONS, AS WINDS SHIFT FROM
SW TO N EARLY THIS MORNING. WINDS BECOME EASTERLY AFTER SUNRISE.
VFR AND DRY WEATHER PREVAIL, WITH MVFR CIGS POSSIBLE CAPE COD
AND ISLANDS LATE IN THE DAY. MARGINAL LLWS 06Z-09Z ACROSS
EASTERN MA, WITH WS020/27040KT.
SATURDAY NIGHT...BOUNDARY SOUTH OF NEW ENGLAND LIFTS NORTH AS A
WARM FRONT. THIS WILL SUPPORT VFR/MVFR CONDITIONS AT 00Z SUN TO
TRANSITION TO IFR/LIFR OVERNIGHT, IN SPOTTY LIGHT RAIN/DRIZZLE
AND AREAS OF DENSE FOG. EAST WINDS BECOME SOUTHEAST.
SUNDAY...WIDESPREAD SHOWERS AND AREAS OF FOG SUPPORTING
IFR/LIFR IN THE MORNING, IMPROVING TO MVFR/VFR LATE IN THE DAY
FROM WEST TO EAST, AS SHOWERS EXIT THE REGION.
KBOS TERMINAL...HIGH CONFIDENCE IN TRENDS. VFR AND DRY WEATHER.
SW WINDS AT PREDAWN, SHIFT TO THE NORTH BY DAYBREAK, THEN
EASTERLY THEREAFTER. VFR AND DRY WEATHER THROUGH SATURDAY
EVENING PUSH, THEN IFR/LIFR OVERNIGHT INTO SUNDAY MORNING, IN
AREAS OF DRIZZLE AND DENSE FOG.
KBDL TERMINAL...HIGH CONFIDENCE.
VFR AND DRY WEATHER TODAY. SSW WINDS AT PREDAWN, BECOME NORTH
TOWARD DAYBREAK, THEN EASTERLY THIS AFTERNOON.
OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...
SUNDAY NIGHT: VFR. BREEZY.
MONDAY: BREEZY.
MONDAY NIGHT: SLIGHT CHANCE SHSN.
TUESDAY: BREEZY. CHANCE SHRA, CHANCE SHSN.
TUESDAY NIGHT: BREEZY.
WEDNESDAY:
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
HIGH CONFIDENCE.
SATURDAY...SW WINDS 15-20 KT WITH GUSTS UP TO 25 KT AT TIMES
AHEAD OF AN APPROACHING COLD WILL VEER TO THE WEST AROUND
DAYBREAK AND THEN NORTH, ALONG WITH SLACKING SPEEDS. THIS WILL
IMPROVE ALL VSBYS BEFORE SUNRISE. AS THE BACKDOOR FRONT MOVES
ACROSS THE MA/RI WATERS, WINDS WILL SHIFT ABRUPTLY FROM NORTH TO
EAST, WITH GUSTS UP TO 30 KT AT TIMES.
OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...
SUNDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF ROUGH SEAS.
CHANCE OF RAIN SHOWERS.
MONDAY: WINDS LESS THAN 25 KT. LOCAL ROUGH SEAS.
MONDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT.
TUESDAY: WINDS LESS THAN 25 KT. CHANCE OF RAIN SHOWERS, CHANCE
OF SNOW SHOWERS.
TUESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT.
WEDNESDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EDT EARLY THIS MORNING FOR
ANZ231>235-237.
GALE WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON FOR
ANZ231>235-237-254>256.
SMALL CRAFT ADVISORY UNTIL 7 AM EDT THIS MORNING FOR ANZ250.
SMALL CRAFT ADVISORY UNTIL 1 PM EDT THIS AFTERNOON FOR
ANZ254>256.
DISCUSSION...MCMINN/NOCERA
AVIATION...MCMINN/NOCERA
MARINE...NOCERA
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