Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS61 KBOX 282352
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
752 PM EDT TUE JUL 28 2015

.SYNOPSIS...
ISOLATED TO SCATTERED THUNDERSTORMS WILL COME TO AN END THIS
EVENING. OTHERWISE...HOT AND HUMID CONDITIONS EXPECTED THROUGH
THURSDAY. A COLD FRONT WILL BRING SCATTERED THUNDERSTORMS LATE
THURSDAY AND THURSDAY NIGHT. WARM AND LESS HUMID WEATHER IS
EXPECTED FRIDAY INTO THE WEEKEND. THERE WILL BE CHANCES FOR MORE
SHOWERS AND THUNDERSTORMS LATE THIS WEEKEND INTO EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...

730 PM UPDATE...

LAST OF WEAKENING SHOWERS HAVE MOVED OFF THE RI COAST AND IN THE
VICINITY OF KBID AT 2330Z. THE ISOLD SHOWERS THAT DEVELOPED INLAND
W OF KORH AND NEAR KBED HAVE ALSO MOSTLY DISSIPATED. NOTING
LEFTOVER DEBRIS CLOUDS FROM THE CONVECTION HANGING ACROSS INTERIOR
MA/RI/NE CT ON LATEST IR SATELLITE IMAGERY. SHOULD SEE THOSE
CLOUDS TEND TO DISSIPATE. HOWEVER...MORE CLOUDS MOVE MAY TRAVERSE
ACROSS THE REGION IN THE N-NW FLOW ALOFT OUT OF N NEW ENGLAND AND
UPSTATE NY OVERNIGHT.

NOTING LOW CLOUDS ALREADY AT KACK...SO WILL LIKELY SEE LOW CLOUDS
EXPAND ALONG THE S COAST IN THE SOUPY AIRMASS. PATCHY FOG WILL
LIKELY DEVELOP ESPECIALLY IN AREAS WHERE RAIN FELL THIS AFTERNOON
INTO THE EVENING.

HAVE UPDATED NEAR TERM FORECAST TO BRING CONDITIONS CURRENT.

PREVIOUS DISCUSSION...

EXPECT DRY WEATHER TO PREVAIL FOR THE REST OF THE NIGHT. LOW
TEMPS WILL RANGE FROM THE LOWER TO MIDDLE 60S IN THE OUTLYING
LOCATIONS WITH UPPER 60S TO LOWER 70S IN THE URBAN HEAT ISLANDS OF
DOWNTOWN BOSTON AND PROVIDENCE.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
***HOT BUT DRY WEATHER ON WEDNESDAY***

UPPER LEVEL RIDING WILL BUILD ACROSS SOUTHERN NEW ENGLAND.  THIS
SHOULD RESULT IN PARTLY TO MOSTLY SUNNY SKIES...DESPITE SOME
DIURNAL CUMULUS CLOUDS.  850 MB TEMPS AROUND +18C WILL YIELD HIGHS
BETWEEN 90 AND 95 ACROSS MOST OF THE REGION.  WEAK PRESSURE GRADIENT
WILL RESULT IN TEMPS A BIT COOLER ALONG PORTIONS OF THE COAST.
WHILE THERE IS A LOW RISK OF A VERY ISOLATED
SHOWER/THUNDERSTORM...GIVEN UPPER LEVEL RIDGING OPTED FOR A DRY
FORECAST.  EVEN IF ONE WERE TO HAPPEN IT PROBABLY WOULD BE VERY
BRIEF AND COVER SUCH A SMALL AREA OF OUR REGION...NOT WORTH A
MENTION AT THIS POINT.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
SYNOPTIC OVERVIEW AND MODEL PREFERENCES...

AS H5 CUTOFF LOW SETS UP ACROSS HUDSON BAY/ONTARIO/W QUEBEC AND A
NEGATIVE NAO PATTERN IN PLACE...A FAST UPPER FLOW WILL CONTINUE
ACROSS THE NORTHERN STREAM THROUGH THIS PERIOD. SHORT WAVES IN THIS
FLOW WILL BRING CHANCES FOR SHOWERS/THUNDERSTORMS...THOUGH TIMING OF
EACH INDIVIDUAL SYSTEM IS IN QUESTION BEYOND FRIDAY DUE TO THE FAST
FLOW. MAY START TO SEE THIS LONG WAVE PATTERN BREAK DOWN EARLY NEXT
WEEK...THOUGH LOW CONFIDENCE ON THIS TIMING THIS FAR OUT.

NOTED VERY GOOD CONTINUITY AND TIMING OF APPROACHING SYSTEM LATE
THIS WEEK AMONGST THE MEDIUM MODEL SUITE...THEN TIMING AND PLACEMENT
OF SYSTEMS THIS WEEKEND INTO EARLY NEXT WEEK IN QUESTION.  SO...
WENT WITH A BLEND OF 12Z GFS/00Z ECMWF OP MODEL RUNS THROUGH FRIDAY
NIGHT...THEN TRANSITIONED OVER TO AN OVERALL BLEND OF AVAILABLE
GUIDANCE INCLUDING GEFS/ECENS LATER IN THE PERIOD WHICH GAVE GOOD
CONSISTENCY.

WEDNESDAY NIGHT...
WEAK SHORT WAVE RIDGING WILL CROSS THE REGION WED NIGHT. WILL SEE
SULTRY CONDITIONS...WHICH WILL LIKELY LEAD TO PATCHY FOG WHICH MAY
BECOME LOCALLY DENSE ALONG THE S COAST...CAPE COD AND THE ISLANDS
AFTER MIDNIGHT. EXPECT OVERNIGHT LOWS IN THE UPPER 60S TO LOWER
70S THOUGH A BIT MILDER IN THE URBAN CENTERS.

THURSDAY THROUGH FRIDAY NIGHT...
PRETTY VIGOROUS H5 SHORT WAVE MOVES ALONG IN W-NW FLOW ALOFT.
CURRENT TIMING SUGGESTS ARRIVING AFTER 18Z THU ACROSS THE E
SLOPES OF THE BERKSHIRES THAN PUSHING INTO THE CT VALLEY LATE IN
THE DAY. LOOKS LIKE MOST ACTION WILL OCCUR THU NIGHT INTO FRI AS
FRONT MOVES SLOWLY BUT STEADILY ACROSS. WITH GOOD PUSH OF DRIER
AIR BEHIND THIS FRONT...NOTING PWATS INCREASE TO 1.9 TO 2.1 INCHES
DURING THE NIGHT WITH HIGHEST VALUES ACROSS S COASTAL AREAS. ALSO
GOOD ELEVATED CONVECTION SIGNALS...WITH TQ VALUES IN THE LOW 20S
ALONG WITH K INDICES IN THE MID 30S. SPC HAS ALSO MENTIONED
MARGINALLY SEVERE CONDITIONS AS THE PRECIP MOVES INTO FAR WESTERN
AREAS LATE IN THE DAY. SOMETHING TO BE WATCHED.

HAVE LIKELY SHOWERS/SCT TSTMS MOVING ACROSS THE REGION OVERNIGHT.
ALSO USED ENHANCED WORDING FOR HEAVY RAINFALL.

EXPECT FRONT TO CLEAR THE COAST FRI MORNING. ISOLD THUNDER MAY
LINGER THROUGH MID MORNING AS BEST INSTABILITY MOVES OFFSHORE.
SOME SHOWERS MAY LINGER ACROSS THE CAPE AND ISLANDS UNTIL AROUND
MIDDAY THEN SHOULD EXIT. NOTING A BRIEF BREAK IN THE HUMID
CONDITIONS AS DEWPTS FALL BACK TO THE 50S AWAY FROM THE COAST.
TEMPS WILL STILL BE WARM THOUGH...WITH HIGHS MAINLY IN THE LOWER-
MID 80S.

FRIDAY NIGHT WILL BE DRY AND COMFORTABLE ESPECIALLY ACROSS
CENTRAL AND W MA INTO N CT. EXPECT LOWS IN THE 60S...THOUGH MAY
LINGER AROUND 70 ACROSS THE OUTER CAPE AND ISLANDS.

SATURDAY-SUNDAY...
NOTING ANOTHER DIP IN THE LONG WAVE TROUGH ACROSS THE GREAT LAKES
AS A SHORT WAVE MOVES IN THE UPPER FLOW. OPERATIONAL MODELS HAVING
TROUBLE HANDLING THIS FEATURE...THOUGH DOES LOOK LIKE THERE MAY BE
SOME ISOLD SHOWER/TSTM ACTIVITY AS WEAK FRONT CROSSES SAT NIGHT
INTO SUN MORNING. LOOKS LIKE BEST SHOT FOR NOW WILL BE ACROSS THE
CT VALLEY AND ALONG E COAST...THOUGH COULD SEE ISOLD ACTIVITY
ANYWHERE. SOMEWHAT LOWER CONFIDENCE DURING THIS TIMEFRAME.

MONDAY-TUESDAY...
THE H5 CLOSED LOW OVER HUDSON/JAMES BAYS HINTS IN SHIFTING SLOWLY
E ACROSS N QUEBEC DURING THIS TIMEFRAME...BUT STILL SEEING LONG
WAVE TROUGHING ACROSS THE GREAT LAKES. MAY SEE PERIODS OF
SHOWERS/TSTMS MAINLY DURING THE DAYLIGHT HOURS BOTH MON AND
TUE...THOUGH SOME QUESTION ON EXACT TIMING THIS FAR OUT. WILL
REMAIN WARM AND HUMID DURING THIS TIMEFRAME.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH WEDNESDAY AFTERNOON/...

TONIGHT...MODERATE CONFIDENCE. EXPECT MAINLY VFR CONDITIONS. WILL
LIKELY SEE PATCHY FOG DEVELOP ALONG S COAST AND TYPICALLY PRONE
INLAND LOCATIONS WITH LOCAL MVFR-IFR VSBYS. MAY ALSO SEE IFR-LIFR
CIGS MAINLY ACROSS CAPE COD AND THE ISLANDS.


ANY ISOLATED TO SCATTERED CONVECTION
SHOULD COME TO AN END BY 7 OR 8 PM.  OTHERWISE...VFR FOR MOST SITES
EXCEPT FOR SOME PATCHY FOG IN THE TYPICALLY PRONE LOCATIONS.
ALSO...CANNOT RULE OUT IFR IN STRATUS AND FOG ACROSS FAR SE MASS
INCLUDING THE CAPE AND ISLANDS...BUT CONFIDENCE IN THAT IS LOW.

WEDNESDAY...HIGH CONFIDENCE IN VFR CONDITIONS.

KBOS TERMINAL...HIGH CONFIDENCE IN MAINLY VFR THROUGH TONIGHT.
CONVECTION WILL LIKELY REMAIN WEST OF THE BOSTON TERMINAL...BUT
STILL A LOW RISK THAT SOMETHING COULD DEVELOP THROUGH 8 PM

KBDL TERMINAL...HIGH CONFIDENCE IN MAINLY VFR THROUGH TONIGHT.  VERY
LOW RISK OF AN ISOLATED THROUGH 8 PM.

OUTLOOK /WEDNESDAY NIGHT THROUGH SUNDAY/...

WEDNESDAY NIGHT...MODERATE TO HIGH CONFIDENCE. WILL SEE PATCHY
FOG WITH MVFR-IFR CONDITIONS MAINLY NEAR OR AFTER MIDNIGHT.

THURSDAY...MODERATE CONFIDENCE. PATCHY MVFR-IFR IN FOG IMPROVING
TO VFR BY MID MORNING. HOWEVER...LOW PROB THAT MVFR-IFR IN LOW
CLOUDS AND PATCHY FOG MAY LINGER ALONG THE SOUTH COAST. CHANCE OF
SHOWERS AND THUNDERSTORMS MOVE INTO WESTERN AREAS AFTER 18Z...THEN
SHIFTING E BY EVENING.

THURSDAY NIGHT...MODERATE CONFIDENCE. PATCHY MVFR CIGS/VSBYS IN
SCATTERED SHOWERS/THUNDERSTORMS. LOCALLY HEAVY RAINFALL LIKELY...
ESPECIALLY ACROSS RI/SE MA AROUND OR AFTER MIDNIGHT. IMPROVING
CONDITIONS AFTER MIDNIGHT ACROSS N CENTRAL AND W MA INTO N CENTRAL
CT.

FRIDAY AND SATURDAY...MODERATE TO HIGH CONFIDENCE. LINGERING
SHOWERS/ISOLD THUNDERSTORMS AND PATCHY FOG ALONG S COAST...
OTHERWISE MAINLY VFR THROUGH THE REMAINDER OF FRIDAY THROUGH SAT.
ISOLD SHOWERS/TSTMS POSSIBLE SAT NIGHT WITH LOCAL MVFR CONDITIONS.
LOWER CONFIDENCE ON TIMING.

SUNDAY...MODERATE CONFIDENCE. MAINLY VFR.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TONIGHT THROUGH WEDNESDAY AFTERNOON/...HIGH CONFIDENCE.

WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS
THROUGH WEDNESDAY AFTERNOON.  MAIN CONCERN WILL BE A FEW STRONG TO
SEVERE  STORMS ACROSS THE ADJACENT SOUTH COASTAL WATERS THROUGH 7 OR
8 PM.  LOCALLY STRONG WIND GUSTS AND PERHAPS ISOLATED HAIL ARE THE
MAIN CONCERNS.  ALSO...SOME PATCHY FOG IS POSSIBLE THIS EVENING NEAR
THE ISLANDS BUT VISIBILITIES SHOULD IMPROVE AFTER MIDNIGHT AS WINDS
TURN WEST.

OUTLOOK /WEDNESDAY NIGHT THROUGH SATURDAY/...

WEDNESDAY NIGHT AND THURSDAY...EXPECT LIGHT SW WINDS WED NIGHT
INTO THU...THEN PICKING UP DURING THU AFTERNOON. MAY SEE GUSTS TO
20 KT. SEAS 4 FT OR LESS. PATCHY FOG WED NIGHT INTO THU MORNING
LOWERING VSBYS.

THURSDAY NIGHT...SW WINDS GUSTING TO 20 KT MAINLY OVER THE OPEN
WATERS. SEAS REACHING AROUND 5 FT. PATCHY FOG ALONG WITH SCT
SHOWERS/TSTMS LOWERING VSBYS.

FRIDAY AND SATURDAY...COLD FRONT SLOWLY MOVES OFFSHORE. ANOTHER
WEAK FRONT MAY ENTER THE WATERS LATE SAT OR SAT NIGHT. SEAS OVER
THE OPEN WATERS UP TO AROUND 5 FT DURING FRI...SUBSIDING FRI
NIGHT BUT MAY BUILD AGAIN SAT NIGHT.

SUNDAY...WINDS AND SEAS BELOW SMALL CRAFT CRITERIA.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...AIR QUALITY ALERT FROM 11 AM TO 11 PM EDT WEDNESDAY FOR
     MAZ017>024.
RI...AIR QUALITY ALERT FROM 11 AM TO 11 PM EDT WEDNESDAY FOR
     RIZ005>008.
MARINE...NONE.

&&

$$
SYNOPSIS...FRANK/EVT
NEAR TERM...FRANK/EVT
SHORT TERM...FRANK
LONG TERM...EVT
AVIATION...FRANK/EVT
MARINE...FRANK/EVT


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.