Area Forecast Discussion
Issued by NWS Boston, MA

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000
FXUS61 KBOX 230201
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1001 PM EDT FRI AUG 22 2014

.SYNOPSIS...
THE RISK FOR A FEW SHOWERS WILL LINGER INTO SATURDAY...OTHERWISE
DRY THIS WEEKEND AS HIGH PRESSURE BUILDS SOUTH INTO NEW ENGLAND
LATE SATURDAY INTO SUNDAY. DRY WEATHER WITH A WARMING TREND IS
LIKELY DURING THE EARLY AND MIDDLE PORTIONS OF NEXT WEEK. A FRONT
MAY APPROACH FROM QUEBEC LATE NEXT WEEK WITH A LOW CHANCE OF
UNSETTLED WEATHER.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
10 PM UPDATE...
BULK OF THE -SHRA ACTIVITY CONTINUES TO WAIN THIS EVENING THANKS
TO BOTH A LOSS OF DIURNAL HEAT SUPPORT AND THE FACT THAT SHORTWAVE
ENERGY BEGINS TO MOVE OFFSHORE. NOT OUT OF THE QUESTION AN
ISOLATED -SHRA MOVES THROUGH CENTRAL PORTIONS OF THE BOX
CWA...BUT WILL ONLY HIGHLIGHT ISOLATED CHANCES WITH THIS UPDATE.
OTHERWISE. CONTINUE TO NOTE LOW CLOUDS MOVING IN FROM THE E AND
INTERIOR CLOUDS LOWERING THANKS TO ONSHORE FLOW. THIS WILL LIKELY
MITIGATE FOG DEVELOPMENT SOMEWHAT AS IT WILL LIMIT RADIATIVE
PROCESSES. WILL STILL NEED TO MONITOR FOR FOG/DZ MOVING IN
OFFSHORE ALTHOUGH SOUNDINGS DO STILL HAVE A DRY LAYER JUST ABOVE
THE SFC AT 00Z...WHICH WOULD HAVE TO BE OVERCOME FOR DZ.
THEREFORE...WILL CONTINUE TO HOLD OFF ON DZ MENTION FOR THE TIME
BEING. OTHERWISE...FORECAST ON TRACK FOR THE MOST PART. WILL
MAINTAIN THE POPS THROUGH THE OVERNIGHT AS YET ONE LAST SHORTWAVE
WILL BE DIVING S DURING THE MORNING HOURS.

PREVIOUS DISCUSSION...
THE COLUMN BEGINS TO DRY FROM THE NORTH AS NOTED BY DECREASING
PWATS AND MUCH LOWER KI VALUES APPROACHING FROM THE NE. BEST
CHANCE OF ANY SHOWERS WILL BE BEFORE MIDNIGHT.

STRATUS WILL LIKELY REDEVELOP TONIGHT WITH PLENTIFUL LOW LEVEL
MOISTURE IN LIGHT EASTERLY FLOW. SOME FOG LIKELY AS WELL BUT WE
ARE NOT EXPECTING IT TO BE WIDESPREAD. CAN NOT RULE OUT SOME
PATCHY DRIZZLE IN EASTERN NEW ENG AS MID LEVEL DRYING MOVES IN
OVER LOW LEVEL MOISTURE.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
SATURDAY...
MID LEVEL TROF AXIS AND LAST SHORTWAVE SWINGS SOUTH ACROSS THE
REGION...BUT AT THE SAME TIME MID LEVEL DRYING IS MOVING IN SO
EXPECT LESS COVERAGE OF SHOWERS. BEST CHANCE WILL BE IN N/NW ZONES
AS A SECONDARY AREA OF HIGHER MOISTURE AND KI VALUES MOVES IN FROM
THE N. HOWEVER...IMPROVEMENT AND PARTIAL CLEARING EXPECTED
BY MID/LATE AFTERNOON AS THE TROF SHIFTS S OF THE REGION. TEMPS
EXPECTED TO BE SIMILAR TO TODAY...PERHAPS A FEW DEGREES WARMER IN
SOME INTERIOR LOCATIONS BUT STILL BELOW NORMAL.

SATURDAY NIGHT...
SFC HIGH BUILDS INTO SNE WHICH WILL BRING MOSTLY CLEAR SKIES AND
LIGHT WINDS. HOWEVER...PATCHY DENSE RADIATION FOG EXPECTED IN
NORMAL FOG PRONE LOCATIONS. A COOL NIGHT WITH MINS MOSTLY IN THE
50S.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
HIGHLIGHTS...

* DRY WEATHER EXPECTED FOR MOST OF THE PERIOD
* WARMER...MORE HUMID CONDITIONS MOVE IN AROUND EARLY TO MIDDLE
  PORTIONS OF NEXT WEEK
* UNCERTAINTY CONTINUES AS A COLD FRONT APPROACHES FROM QUEBEC
  LATE NEXT WEEK

OVERVIEW AND MODEL PREFERENCES...
MEDIUM RANGE MODELS REMAIN IN PRETTY GOOD AGREEMENT INTO EARLY
NEXT WEEK...THEN START TO DIVERGE AROUND THE THURSDAY INTO EARLY
FRIDAY TIMEFRAME DUE TO THE APPROACH OF A COLD FRONT OUT OF
QUEBEC. ALSO NOTING MODELS ARE TRYING TO BRING A SYSTEM AROUND
THE WESTERN PERIPHERY OF THE BERMUDA HIGH OUT OF THE TROPICS.

USED A BLEND OF AVAILABLE MODELS THROUGH WEDNESDAY...THEN
TRANSITIONED OVER TO THE ENSEMBLES WITH LESSER EMPHASIS PLACED ON
THE 00Z/12Z OP RUNS LATE NEXT WEEK. 00Z/12Z ECMWF RUNS SEEM A BIT
TOO FAST IN BRINGING THE FRONT ACROSS THE REGION ON THU...WHILE
THE 12Z GFS BRINGS THE FRONT ACROSS LATE THU NIGHT/FRI...KIND OF
CATCHING UP TO THE EC. AGREE WITH PREVIOUS FORECASTER WITH REGARDS
TO THE STRENGTH OF THE DEVELOPING RIDGE OVER THE REGION...WHICH
MAY SLOW THINGS DOWN FURTHER.

DETAILS...

SUNDAY...HIGH PRES AT SURFACE AND ALOFT WILL BUILD DOWN THE COAST
OUT OF EASTERN CANADA. ONSHORE FLOW WILL HOLD TEMPS IN THE LOWER
70S ALONG THE COAST...RANGING UP TO THE UPPER 70S ACROSS THE CT
VALLEY.

MONDAY THROUGH WEDNESDAY...HIGH PRES RIDGE BUILDS FROM THE
MARITIMES TO THE MID ATLC STATES OVER TIME...WITH THE RIDGE AXIS
OVER THE TOP OF THE REGION ON MONDAY THAT SLOWLY SINKS S. THIS
WILL CAUSE WINDS TO SHIFT TO S-SW...BRINGING MILDER AND MORE
HUMID AIR INTO THE REGION. EXPECT TO SEE HIGHS MAINLY IN THE
LOWER-MID 80S DURING THIS TIMEFRAME. WITH LIGHT PRES GRADIENT ON
MON AND TUE...SEA BREEZES WILL LIKELY DEVELOP KEEPING IT A BIT
COOLER ALONG THE SHORELINE. ONCE THE S-SW FLOW IS ESTABLISHED...
TEMPS ALONG THE S COAST MAY ALSO BE A BIT COOLER ON WED. SOME
CLOUDS MAY START TO MOVE IN WED NIGHT...BUT TIMING IN QUESTION.

THURSDAY-FRIDAY...LOWER CONFIDENCE ON THIS PORTION OF THE
FORECAST. FOR NOW...MAY SEE FRONTAL SYSTEM TRY TO WORK S OUT OF
QUEBEC AROUND LATE THU/THU NIGHT TIMEFRAME. QUESTION WILL ALSO BE
HOW MUCH AVAILABLE MOISTURE WILL BE ASSOCIATED WITH THIS SYSTEM.
DID KEEP ONLY LOW CHANCE POPS MAINLY FOR THE INTERIOR FOR THU
AFTERNOON/EVENING. VERY LITTLE INSTABILITY WITH THIS...BUT CAN
NOT RULE OUT AN ISOLD TSTM SO DID MENTION THIS. CURRENT FORECAST
SUGGESTS A DRIER AND COOLER DAY ON FRIDAY.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

SHORT TERM...THROUGH SATURDAY NIGHT...MODERATE CONFIDENCE.

TONIGHT...MAINLY VFR CONDITIONS THROUGH 03Z-04Z...THEN EXPECT
LOWERING CIGS BACK TO MVFR-IFR OVERNIGHT. SCT SHOWERS LINGERING
INTO THE EVENING...ESPECIALLY W...WHICH WILL TEND TO DISSIPATE
OVERNIGHT. FAIRLY CONFIDENT OF TREND...BUT TIMING IS LESS
CERTAIN. ALSO LOWER CONFIDENCE ON EXTENT OF FOG DEVELOPMENT
TONIGHT. AT THIS TIME...BEST CHANCE FOR FOG APPEARS TO BE IN THE
CT VALLEY...AND COULD SEE SOME ALONG IMMEDIATE E COAST.

SATURDAY...CONDITIONS IMPROVE TO VFR BY MIDDAY WITH AT LEAST
PARTIAL CLEARING DEVELOPING DURING THE AFTERNOON FROM THE NORTH
AND EAST. A FEW SHOWERS STILL POSSIBLE...MAINLY NW.

SATURDAY NIGHT...MAINLY VFR...BUT PATCHY LATE NIGHT FOG
DEVELOPING IN NORMAL FOG PRONE LOCATIONS.

KBOS TERMINAL...MODERATE CONFIDENCE. EXPECT CIGS TO LOWER TO MVFR
THIS EVENING. TIMING UNCERTAIN AND COULD BE A FEW HOURS EARLIER OR
LATER THAN FORECAST INDICATES.

KBDL TERMINAL...MODERATE CONFIDENCE. EXPECT CIGS TO LOWER TO MVFR
TONIGHT. TIMING UNCERTAIN AND COULD BE A FEW HOURS EARLIER OR
LATER THAN FORECAST INDICATES.

OUTLOOK...SUNDAY THROUGH WEDNESDAY...

HIGH CONFIDENCE VFR. LOW PROBABILITY OF PATCHY MVFR/IFR FOG EACH
NIGHT. SEA BREEZES POSSIBLE MONDAY AND TUESDAY.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.

SHORT-TERM...THROUGH SATURDAY NIGHT...HIGH CONFIDENCE.

E/NE FLOW WILL PERSIST THROUGH THE PERIOD. WINDS COULD GUST TO
15-20 KT TONIGHT INTO SAT GIVEN MODEST GRADIENT IN PLACE...BUT A
DECREASE IN WIND EXPECTED LATE SAT AND ESPECIALLY SAT NIGHT AS
THE SFC HIGH BUILDS INTO REGION.

OUTLOOK...SUNDAY THROUGH WEDNESDAY...

HIGH CONFIDENCE.

HIGH CONFIDENCE. QUIET BOATING WEATHER IS EXPECTED FOR MUCH OF
THIS PERIOD WITH HIGH PRESSURE ACROSS THE REGION. LOW PROBABILITY
OF PATCHY OVERNIGHT FOG LIMITING VISIBILITIES.

SEAS MAY APPROACH 5 FT ACROSS THE OUTERMOST SOUTHERN COASTAL
WATERS ON WEDNESDAY WITH INCREASING S SWELL.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...KJC/EVT
NEAR TERM...KJC/DOODY
SHORT TERM...KJC
LONG TERM...EVT
AVIATION...KJC/EVT
MARINE...KJC/EVT


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