679
FXUS61 KBOX 180713
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOSTON/NORTON MA
313 AM EDT SAT APR 18 2026
WHAT HAS CHANGED
MORE GUIDANCE STARTING TO INDICATE THE CHANCE FOR SOME SCATTERED
SHOWERS MONDAY DUE TO THE PRESENCE OF A POSSIBLE WEAK LOW
PRESSURE.
KEY MESSAGES
- COOL, CLOUDY, AND MAINLY DRY TODAY. SPLASHOVER POSSIBLE FOR
THE EAST COAST DURING THE SUNDAY MORNING HIGH TIDE.
- STRONG COLD FRONT BRINGS A ROUND OF WIDESPREAD SHOWERS
SUNDAY, LEAVES COLDER TEMPERATURES AND DRIER CONDITIONS IN ITS
WAKE.
- COOLER THAN NORMAL MONDAY. WHILE GENERALLY DRY WEATHER IS
EXPECTED, A WEAK AREA OF LOW PRESSURE COULD BRING CLOUDS AND
SCATTERED SHOWERS.
- SEASONABLE TEMPERATURES WEDNESDAY, THOUGH ANOTHER COLD FRONT
ARRIVES AND TEMPERATURES FALL ONCE MORE FOR THE SECOND HALF OF
THE WEEK.
DISCUSSION
KEY MESSAGE 1...COOL, CLOUDY, AND MAINLY DRY TODAY. SPLASHOVER
POSSIBLE FOR THE EAST COAST DURING THE SUNDAY MORNING HIGH TIDE.
LOW PRESSURE REMAINS JUST OFFSHORE TODAY, MAINTAINING ONSHORE FLOW
AND ADVECTING IN MARINE STRATUS. THIS STRATUS HAS ALREADY STARTED TO
MAKE ITS WAY INTO SOUTHERN NEW ENGLAND AND WILL CONTINUE TO DO SO
FROM EAST TO WEST THROUGH THE DAY TODAY. WITH PERSISTENT CLOUD COVER
AND NE WINDS, TEMPERATURES TODAY WILL BE COOLER, MAXING OUT IN THE
UPPER 40S AND LOW 50S CLOSER TO THE EASTERN COAST. THE INTERIOR
CAN EXPECT ONLY SLIGHTLY WARMER HIGHS COMPARED TO THE EAST,
REACHING THE LOW 60S IN THE CT VALLEY AND THE UPPER 50S
ELSEWHERE. RIDGING OVERHEAD WILL HELP KEEP THE REGION DRY AS
WELL.
THERE IS A CHANCE THAT SPOTS ALONG THE EASTERN COASTLINE COULD SEE
SOME SPLASHOVER OR MINOR COASTAL FLOODING DURING THE SUNDAY MORNING
HIGH TIDE. HIGH ASTRONOMICAL TIDES COMBINED WITH PERSISTENT E/NE
WINDS ELEVATE THIS RISK DURING THIS PERIOD. WILL CONTINUE TO MONITOR
OVER THE NEXT FORECAST CYCLE AND ISSUE HEADLINES IF NEEDED.
KEY MESSAGE 2...STRONG COLD FRONT BRINGS A ROUND OF WIDESPREAD
SHOWERS SUNDAY, LEAVES COLDER TEMPERATURES AND DRIER CONDITIONS IN
ITS WAKE.
AN INCOMING STRONG COLD FRONT SUNDAY WILL LIKELY BRING A ROUND OF
WIDESPREAD SHOWERS. THIS FRONT IS PART OF A POTENT UPPER LEVEL
TROUGH THAT WILL BE SHIFTING EAST FROM THE GREAT LAKES SUNDAY INTO
MONDAY. AHEAD OF THIS FRONT AND TROUGH, PWAT VALUES CLIMB TO
ANOMALOUSLY HIGHER VALUES AROUND 1.25"-1.30" SUNDAY MORNING AFTER
DROPPING MOSTLY 0.5" DURING THE DAY TODAY. AS THE FRONT PUSHES
THROUGH, THE FORCING FROM IT INTERACTING WITH THIS ELEVATED MOISTURE
WILL LEAD TO WIDESPREAD SHOWERS SUNDAY. HIGH-RES GUIDANCE STILL HAS
HINTS OF MUCAPE AROUND 500 J/KG DURING THE DAY THAT COULD BE A
FACTOR IN SOME EMBEDDED THUNDERSTORMS WITH THESE SHOWERS. SOME
DOWNPOURS CANNOT BE RULED OUT AS WELL, ESPECIALLY IN ANY ISOLATED
THUNDERSTORMS THAT MAY DEVELOP. DESPITE CONTINUED RAIN TODAY, FLASH
FLOODING IS NOT A BIG CONCERN. AT MOST, WE COULD EXPECT SOME POOR
DRAINAGE AREAS TO SEE SOME PONDING.
COLDER AND DRIER AIR IS LEFT IN THE FRONT'S WAKE, REINFORCED BY
BREEZY W TO NW WINDS STARTING SUNDAY AFTERNOON. GUSTS TO 25 MPH ARE
A POSSIBILITY POST-FRONT. SHOWERS MAY END WITH A MIX OF SOME SNOW IN
THE HIGHER ELEVATIONS OF THE BERKSHIRES SUNDAY EVENING AS THIS
COLDER AIRMASS TAKES HOLD, BUT ANY ACCUMULATIONS ARE NOT EXPECTED AT
THIS TIME. LOWS SUNDAY NIGHT WILL LIKELY FALL BELOW FREEZING OUTSIDE
OF URBAN AREAS, WHILE THE CITIES CAN EXPECT LOWS IN THE MID TO UPPER
30S.
KEY MESSAGE 3...COOLER THAN NORMAL MONDAY. WHILE GENERALLY DRY
WEATHER IS EXPECTED, A WEAK AREA OF LOW PRESSURE COULD BRING CLOUDS
AND SCATTERED SHOWERS.
THE UPPER LEVEL TROUGH SETTLES OVERHEAD MONDAY, AND WITH IT,
UNSEASONABLY COLD AIR MOVES IN IN THE MIDST OF CAA. 925 MB
TEMPERATURES FALL BELOW 0C AND MAY EVEN DIP TO -5C BY MONDAY
MORNING. BREEZY W TO NW WINDS CONTINUE, AND HIGHS MAY NOT CLIMB OUT
OF THE UPPER 40S AND LOW 50S MONDAY AFTERNOON. THESE WINDS WILL
START TO DIMINISH AS HIGH PRESSURE APPROACHES FROM THE WEST, AND
LOWS MONDAY NIGHT MAY FALL INTO THE 20S FOR MUCH OF SOUTHERN NEW
ENGLAND. EVEN WITH APPROACHING HIGH PRESSURE, MORE GUIDANCE HAS
STARTED TO LATCH ONTO A WEAK LOW PRESSURE MOVING INTO THE REGION
MONDAY THAT COULD BRING INCREASED CLOUDS AND SCATTERED SHOWERS.
ENSEMBLE MEMBERS (AND DETERMINISTIC MODELS) FROM DIFFERENT GUIDANCE
SUITES HAVE STARTED TO INDICATE SOME SHOWERS MONDAY AS A RESULT OF
THIS WEAK LOW, THOUGH CONFIDENCE IN THIS FEATURE DEVELOPING IS STILL
RELATIVELY LOW. OUTSIDE OF THIS, INCOMING HIGH PRESSURE SHOULD KEEP
THE REGION DRY FOR MUCH OF THE START OF THE WEEK BEFORE IT EXITS
HEADING INTO WEDNESDAY.
KEY MESSAGE 4...SEASONABLE TEMPERATURES WEDNESDAY, THOUGH ANOTHER
COLD FRONT ARRIVES AND TEMPERATURES FALL ONCE MORE FOR THE SECOND
HALF OF THE WEEK.
SOME SHOWERS ARE A POSSIBILITY ONCE AGAIN HEADING INTO WEDNESDAY
MORNING AS ANOTHER SHORTWAVE APPROACHES, BUT MORE SEASONABLE
TEMPERATURES MAKE A RETURN AS THE TROUGH EARLY IN THE WEEK EXITS.
925 MB TEMPERATURES RECOVER TO AROUND 5C WITH SW FLOW RETURNING,
SUPPORTING MORE SEASONABLE HIGHS IN THE UPPER 50S/LOW 60S. NW FLOW
MAKES A RETURN TOWARDS THURSDAY/FRIDAY IN THE WAKE OF ANOTHER FRONT
PASSING THROUGH SOMETIME LATE WEDNESDAY, AND HIGH PRESSURE BUILDS
BACK IN AS RIDGING APPROACHES, WHICH SHOULD KEEP THE REGION DRY YET
CHILLY.
AVIATION /07Z SATURDAY THROUGH WEDNESDAY/
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
06Z TAF UPDATE:
THROUGH 12Z...MODERATE TO HIGH CONFIDENCE ON STRATUS TIMING.
INCREASING NE WINDS DRAWS MARINE STRATUS AND FOG LAYER
WESTWARD, APPEARING TO ARRIVE AT BOS AROUND 07-08Z AND
CONTINUING TO EXPAND WESTWARD TO BDL THROUGH 11-12Z. THIS WILL
BRING IFR-LIFR CEILINGS AND VISBYS IN THE 1-3 SM RANGE (POSSIBLY
1/2SM TO 1/4SM AT TIMES AT BOS AND THE CAPE). LIGHT AND
VARIABLE WINDS WILL CONTINUE TO BECOME NE AT 5-10 KT THROUGH
THE EARLY MORNING HOURS.
TODAY...MODERATE CONFIDENCE.
IFR-LIFR CEILINGS EARLY, WITH IMPROVING VISBYS IN FOG. LATEST
GUIDANCE STILL HAS SOME IFR-MVFR OPTIMISM AROUND 15-18Z, BUT
CEILINGS THEN TREND DOWNWARD AGAIN AS WE MOVE INTO THE
OVERNIGHT PERIOD. NE WINDS 6-12 KT, STRONGEST EASTERN MA.
TONIGHT...MODERATE CONFIDENCE.
CEILINGS DETERIORATE DOWN TO IFR/LIFR LEVELS AGAIN TONIGHT. FOG
MAY RETURN AS WELL, BRINGING VISBYS DOWN TO 2SM AND POSSIBLY
LOWER. NE WINDS VEER AROUND TO SE/S 5-10 KT.
SUNDAY...MODERATE CONFIDENCE.
MAINLY IFR-MVFR WITH STEADY RAIN AND MIST. OUTSIDE CHANCE AT A
RUMBLE OF THUNDER AS STRONG COLD FRONT MOVES THROUGH 18-00Z. SW
WINDS AROUND 10 KT, BECOMING W/NW AND INCREASING TO 10-15 KT
WITH GUSTS 20-25 KT POST-FRONTAL PASSAGE.
KBOS TERMINAL...MODERATE CONFIDENCE IN TAF. BASED ON LATEST
SATELLITE IMAGERY, STRATUS SHOULD MOVE IN AROUND 08Z.
SURROUNDING TERMINALS ALREADY SEEING SOME FOG; WOULD EXPECT FOG
TO MOVE IN BY THE TIME STRATUS ARRIVES. FOG DISPERSES IN THE
MORNING, BUT IFR CEILINGS GENERALLY PERSIST WITH SOME GUARDED
OPTIMISM ON IMPROVEMENT TO IFR/MVFR LEVELS. LIGHT WINDS BECOME
NE 5-10 KT. FOG RETURNS HEADING INTO TONIGHT.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...
SUNDAY NIGHT: VFR. BREEZY. CHANCE RA.
MONDAY: VFR. BREEZY. SLIGHT CHANCE SHRA.
MONDAY NIGHT THROUGH TUESDAY: VFR.
TUESDAY NIGHT THROUGH WEDNESDAY: VFR. BREEZY. SLIGHT CHANCE
SHRA.
MARINE
FORECASTER CONFIDENCE LEVELS...
LOW - LESS THAN 30 PERCENT.
MODERATE - 30 TO 60 PERCENT.
HIGH - GREATER THAN 60 PERCENT.
HIGH CONFIDENCE THROUGH THE WEEKEND.
SEAS 2-4 FT AND WINDS LESS THAN 25 KTS OUT OF NORTHEAST TODAY.
WINDS SHIFT SE TO S TONIGHT AND SHOULD REMAIN LESS THAN 25 KTS.
PASSAGE OF STRONGER COLD FRONT SUN MAY BRING SCA CONDITIONS TO
AT LEAST OUTER WATERS SUN INTO MON. WIND GUSTS MAY LOCALLY
APPROACH 25 KT LATE SUNDAY IN THE OUTER WATERS. WINDS SHIFT NW
FOLLOWING THIS FRONTAL PASSAGE.
OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/...
SUNDAY NIGHT: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT. RAIN LIKELY.
MONDAY: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING 5 FT.
MONDAY NIGHT THROUGH TUESDAY: WINDS LESS THAN 25 KT.
TUESDAY NIGHT: WINDS LESS THAN 25 KT. SEAS LOCALLY APPROACHING
5 FT. SLIGHT CHANCE OF RAIN SHOWERS.
WEDNESDAY: WINDS LESS THAN 25 KT. AREAS OF SEAS APPROACHING
5 FT. SLIGHT CHANCE OF RAIN SHOWERS.
BOX WATCHES/WARNINGS/ADVISORIES
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
DISCUSSION...HRENCECIN
AVIATION...HRENCECIN
MARINE...HRENCECIN
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