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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBOX 171125
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
725 AM EDT MON JUN 17 2013

.SYNOPSIS...
A COLD FRONT FROM THE GREAT LAKES WILL SLIDE ACROSS SOUTHERN NEW
ENGLAND TONIGHT. A SECOND COLD FRONT MAY STALL ACROSS THE REGION
TODAY...THEN SLOWLY MOVE OFFSHORE LATE TUESDAY OR TUESDAY NIGHT.
LARGE HIGH PRESSURE WILL BRING MAINLY DRY AND SEASONABLE CONDITIONS
WEDNESDAY THROUGH FRIDAY...THEN WILL ANCHOR SOUTH OF NEW ENGLAND
SATURDAY. AN APPROACHING WARM FRONT MAY BRING WIDELY SCATTERED
SHOWERS AND THUNDERSTORMS NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
715 AM UPDATE...
CI SHIELD ALONG THE SOUTH COAST IS MOVING TO THE SOUTH. EXPECT
LOTS OF MORNING SUNSHINE...WITH SCT-BKN CU DEVELOPING THIS
AFTERNOON. SCT SHOWERS/TSTMS EXPECTED TO DEVELOP THIS AFTERNOON
AND GIVEN MAGNITUDE OF DEEP LAYER SHEAR WHICH IS RATHER
IMPRESSIVE...POTENTIAL EXISTS FOR ORGANIZED SEVERE WEATHER.
INSTABILITY WILL BE THE KEY AND LATEST FORECASTS SUGGEST MLCAPES
OF 1000+ J/KG WHICH WOULD BE MORE THAN SUFFICIENT FOR SEVERE WX.

PREVIOUS DISCUSSION...
THE OTHER ISSUE OF NOTE TODAY IS THE POTENTIAL FOR AFTERNOON
CONVECTION AS YET ANOTHER SHORTWAVE AND ATTENDANT SFC COLD FRONT
SLIDES S WITHIN CYCLONIC FLOW ALOFT. GUIDANCE HAS BEEN KIND OF
BACK AND FORTH ON THIS POTENTIAL BUT RECENT RUNS ARE ALL
BEGINNING TO  CONVERGE ON THE POSSIBILITY OF UP TO 1000 J/KG
SBCAPE BY THIS AFTERNOON SHOULD WITH SUNSHINE /WHICH IS EXPECTED
FOR MUCH OF THE DAY/. NAM IS A BIT MORE ROBUST HERE BUT IS KEYING
ON HIGHER DWPTS THAN MUCH OF THE MESOSCALE AND GFS/ECMWF
MODELS...SO LEANED AWAY FROM IT/S SOLUTION FOR NOW...BUT WILL HAVE
TO WATCH THIS BECAUSE DWPTS CLOSER TO THE MID 60S ARE CAPABLE OF
PRODUCING 1500+ J/KG INSTEAD. LAPSE RATES ARE MODEST AT ABOUT
6-6.5C/KM ALTHOUGH GFS HAS STEEPENED THESE SOMEWHAT.

WITH STRONG CYCLONIC FLOW ALOFT...AM NOTING UP TO 20-30 KT AND
40-50 KT OF SHEAR AT 0-3 AND 0-6 KM RESPECTIVELY. THEREFORE...EVEN
THOUGH INSTABILITY WILL NOT BE AS HIGH AS ONE MIGHT NORMALLY LOOK
FOR...THE SHEAR SUGGESTS STORMS COULD BECOME ORGANIZED INTO AT
LEAST ORGANIZED MULTI-CELLS STRUCTURES. COMBINE THIS WITH DECENT
D-CAPE IN THE AFTERNOON...AND WILL HAVE TO MONITOR FOR A WIND
THREAT WITH THESE STORMS. HELD OFF ON HAIL THREAT /ALTHOUGH ITS
NON-ZERO/ DUE TO SOUNDINGS SUGGESTING THEIR MAY BE A BIT OF A MID
LVL WARM LAYER LIMITING HAIL CAPE. PWAT VALUES OF 1.0 INCHES PLUS
COULD ALSO CREATE A THREAT FOR HEAVY RAIN.

TAKING ALL OF THIS INTO ACCOUNT...HAVE OPTED TO HOIST SOME
ENHANCED WORDING FOR GUSTY WINDS AND HEAVY RAIN WITH SOME
THUNDERSTORMS POSSIBLE THIS AFTERNOON/EVENING AS THE FRONT
APPROACHES. MASS FIELDS SAYS THIS FIELD RIGHT AROUND PEAK
HEATING. MAY NEED TO CONSIDER UPGRADING THIS WORDING AS NEW MESO-
SCALE GUIDANCE COMES IN AS THERE IS DEFINITE POTENTIAL FOR SOME
STRONG- SEVERE STORMS.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
TONIGHT...
COLD FRONT SLIDES THROUGH THE AREA THEN STALLS IN VICINITY OF
CT/RI AND SE MA AS IT PARALLELS UPPER LVL FLOW. ANY CONVECTION
THAT DEVELOP WILL LIKELY BECOME ELEVATED AND THEN DIMINISH TO
-SHRA AS THE BL DECOUPLES DUE TO LOSS OF HEATING. A FEW STORMS MAY
LINGER TO THE COAST LINES SO MAY NEED TO WATCH THE WATERS
OVERNIGHT EVEN AS STORMS WEAKEN OVERLAND. OTHERWISE...JUST EXPECT
A FAIR AMOUNT OF CLOUDINESS WITH AT LEAST ISOLATED -SHRA AROUND
GIVEN THE LIFT THE FRONT PROVIDES AND A FAIR AMOUNT OF COLUMN
MOISTURE. DWPTS REMAIN ELEVATED IN VICINITY OF AND S OF THE THE
FRONT...SO EXPECT SOME FOG TO DEVELOP ESPECIALLY IN AREAS THAT
HAVE RAIN RAISING SFC MOISTURE.

TUESDAY...
TRICKY FORECAST REGARDING POTENTIAL FOR ANOTHER STRONG-SEVERE
THUNDERSTORM DAY. SFC COLD FRONT WILL BE STALLED ALONG THE
SOUTHERN HALF OF SOUTHERN NEW ENGLAND DURING THE MORNING HOURS.
WHILE THIS WILL PROVIDE THE FOCUS FOR LIFT...AND DWPTS WILL REMAIN
HIGH WITH THE POTENTIAL FOR CAPE VALUES TO ONCE AGAIN REBOUND TO
1000+ J/KG...THE QUESTION WILL BE AVAILABLE SUNSHINE. THE FRONT
WILL LIKELY KEEP AT LEAST SOME BKN CLOUDS IN THE REGION THROUGH
SUNRISE WHICH WOULD SLOW DESTABILIZATION. HOWEVER...SHOULD THE SUN
BREAK OUT...THERE IS THE POTENTIAL FOR AT LEAST AS MUCH IF NOT
MORE INSTABILITY THAN MONDAY. SHEAR WILL BE MUCH THE SAME AS
WELL...40-50 KT FROM 0-6 KM. SPC STILL FOCUSES A SEE TEXT SO WILL
HAVE TO MONITOR FOR ANOTHER ROUND OF STORMS WHICH AT LEAST HAVE
THE POTENTIAL TO BECOME STRONG-SEVERE.

TEMPS UNDER BKN-OVC SKIES WILL BE A BIT COOLER THAN MON...IN THE
MID TO UPPER 70S ALTHOUGH UNDER SUNSHINE COULD REACH CLOSER TO 80+
ESPECIALLY S OF THE STALLED FRONT. HUMID CONDITIONS ALSO ARE
EXPECTED TO CONTINUE WITH DWPTS IN THE LOW TO MID 60S NEAR THE
FRONT...BUT IN NH THE DWPTS WILL BE LOWER FURTHER BEHIND THE
FRONT.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGHLIGHTS...

* DRY AND SEASONABLE WEATHER THROUGH THE END OF THE WEEK
* MORE HUMID NEXT WEEKEND WITH A CHANCE OF SHOWERS/TSTMS

OVERVIEW...
MODELS IN AGREEMENT THROUGH THE END OF THE WEEK WITH POLAR JET
GRADUALLY LIFTING TO THE N BUT BROAD TROF REMAINING ACROSS THE
NE...RESULTING IN MAINLY DRY AND SEASONABLE CONDITIONS. GFS AND
ECMWF BEGIN TO DIVERGE A BIT DURING NEXT WEEKEND AS MIDWEST RIDGE
TRIES TO BUILD EWD.  GFS BRINGS A PIECE OF THIS HEAT INTO SNE AS IT
IS DEPICTING MORE OF A ZONAL FLOW ACROSS GT LAKES INTO NEW ENG...
WHILE ECMWF SHOWS A SLIGHTLY MORE AMPLIFIED DOWNSTREAM TROF AND NW
FLOW ACROSS SNE WHICH KEEPS THE WARM FRONT AND HEAT TO THE SW.
FORECAST CONFIDENCE IS BELOW NORMAL FOR NEXT WEEKEND BUT WE LEANED
TOWARD ECMWF SOLUTION.  THREAT OF SHOWERS/TSTMS WILL INCREASE BY
LATE IN THE WEEKEND AS WARM FRONT APPROACHES FROM THE SW.

TUE NIGHT AND WEDNESDAY...
CHC SHOWERS/TSTMS MAY LINGER INTO THE EVENING...ESPECIALLY S OF THE
MASS PIKE AS THE COLD FRONT MOVES TO THE COAST.  THE FRONT AND ANY
SHOWERS WILL PUSH OFFSHORE OVERNIGHT...BUT CLOUDS WILL LINGER NEAR
THE COAST FOR MUCH OF THE NIGHT AND POSSIBLY INTO WED MORNING AS
CLEARING MOVES INTO NORTHERN ZONES. THIS CLEARING WILL EVENTUALLY
PUSH SOUTH ACROSS REST OF SNE DURING WEDNESDAY.  NEAR SEASONABLE
TEMPS IN THE 70S EXPECTED FOR WEDNESDAY WITH NE FLOW AND SEABREEZES
DEVELOPING NEAR THE COAST.

THURSDAY AND FRIDAY...
MAINLY DRY AND SEASONABLE CONDITIONS EXPECTED TO CONTINUE WITH HIGH
PRES IN CONTROL.  TEMPS MOSTLY IN THE 70S...WITH COOLING SEABREEZES
EXPECTED EACH DAY WITH LIGHT BOUNDARY LAYER FLOW.

SATURDAY AND SUNDAY...
FORECAST CONFIDENCE DECREASES AS GFS/ECMWF DIFFER ON EWD EXTENT OF
WARM SECTOR AIRMASS. AS MENTIONED ABOVE WE LEANED TOWARD THE ECMWF
WHICH KEEPS THE WARM FRONT TO THE WEST WITH INCREASING CHC OF
SHOWERS/TSTMS FROM POSSIBLE MCS...BUT STILL A LOT OF UNCERTAINTY.
TEMP FORECAST ALSO UNCERTAIN AND WILL DEPEND ON POSITION OF WARM
FRONT.  WE UNDERCUT MEX GUIDANCE BY SEVERAL DEGREES MORE IN LINE
WITH ECMWF.

&&

.AVIATION /11Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...

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

OVERVIEW...HIGH CONFIDENCE IN OVERALL TRENDS THROUGH TUESDAY.
           LOWER CONFIDENCE IN SHRA/T-STORMS TODAY AND TUESDAY

VFR IS EXPECTED TO BE THE DOMINANT CATEGORY THROUGH THE DAY TODAY.
HOWEVER...SOME SHOWERS AND THUNDERSTORMS COULD POTENTIALLY FORM
AHEAD OF A COLD FRONT THIS AFTERNOON/EVENING PARTICULARLY INLAND
AND AWAY FROM THE COASTLINES WITH LOCALIZED MVFR CONDITIONS AND
WET RUNWAYS.

THE STORMS DISSIPATE OVERNIGHT TONIGHT BUT SOME SHOWERS ARE LIKELY
TO BE AROUND AS A COLD FRONT CROSSES THE REGION. EXPECT SOME
IMPROVEMENT BEHIND THE FRONT WITH WINDS SHIFTING TOWARD THE W
AGAIN. SOME FOG IS POSSIBLE OVER INTERIOR TERMINALS...WITH SOME
STRATUS AND FOG POSSIBLE ON THE CAPE/ISLANDS AND IMMEDIATE S COAST
PRODUCING IFR/MVFR CONDITIONS.

VFR ONCE AGAIN DOMINATES TUE OUTSIDE OF FOG/STRATUS...BUT EXPECT
ANOTHER ROUND OF SHOWERS AND STORMS POSSIBLE...THIS TIME IT MAY
APPROACH THE COASTLINES.

KBOS TERMINAL...HIGH CONFIDENCE IN OVERALL TAF TRENDS...SLIGHTLY
LOWER CONFIDENCE IN POTENTIAL FOR SHOWER/T-STORM LATE TODAY OR
OVERNIGHT.

KBDL TERMINAL...HIGH CONFIDENCE IN OVERALL TAF TRENDS...SLIGHTLY
LOWER CONFIDENCE IN TIMING OF ANY SHOWERS/T-STORMS LATE TODAY AND
OVERNIGHT.

OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...

TUESDAY NIGHT...MODERATE CONFIDENCE. MVFR POSSIBLE IN SCT
SHOWERS/TSTMS IN THE EVENING. PATCHY MVFR/IFR FOG/STRATUS POSSIBLE
NEAR THE SOUTH COAST.

WEDNESDAY THROUGH FRIDAY...HIGH CONFIDENCE. VFR.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

HIGH CONFIDENCE THROUGH TUESDAY..

TODAY AND TONIGHT...

WINDS SHIFT TO THE SW TODAY WITH GUSTS GENERALLY 10-15 KT ALTHOUGH
MAY NEED TO MONITOR FOR 20-25 KT AGAIN NEAR THE CAPE AND ISLANDS
THIS AFTERNOON. OTHERWISE...THE SOUTHERLY COMPONENT WILL ALLOW THE
5-6 FT SEAS ON THE OCEAN WATER S OF RI/MA TO PERSIST SO WILL
CONTINUE THE SMALL CRAFT ADVISORY THROUGH 00Z. OTHERWISE...WILL
NEED TO MONITOR FOR SOME T-STORMS WHICH MAY REACH THE COASTLINE
BY THE EVENING AND CONTINUE INTO THE OVERNIGHT HOURS. FOG AND
STRATUS MAY DEVELOP LATE TONIGHT WITH SOME REDUCTION IN VSBYS.

TUESDAY...
A STALLED FRONT COULD ALLOW FOR MORE SHOWERS AND STORMS ACROSS THE
WATERS DURING THE DAY...BUT OUTSIDE OF ANY OF THESE STORMS MAINLY
QUIET BOATING WEATHER IS EXPECTED.

OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...

HIGH CONFIDENCE.

WINDS AND SEAS BELOW SMALL CRAFT CRITERIA THROUGH THE PERIOD. NE
WINDS MAY GUST TO 20 KT WED.

&&

.HYDROLOGY...
-- Changed Discussion --
RIVERS CONTINUE TO RECEDE ACROSS THE REGION...WITH MOST FALLING
BELOW FLOOD STAGE YESTERDAY AND OVERNIGHT. ONLY THE CHARLES RIVER
AT DOVER AND THE PAWCATUCK AT WESTERLY REMAIN ABOVE FLOOD STAGE.

THERE IS THE THREAT FOR SHOWERS AND STRONG THUNDERSTORMS TODAY AND
TUESDAY WHICH COULD PROVIDE HEAVY RAIN. THIS MAY LEAD TO SOME
LOCALIZED URBAN AND POOR DRAINAGE FLOOD AND MAY ALTER THE TIMING
OF RIVERS OR EVEN ALLOW THEM TO RISE AGAIN AS WELL. THIS WILL HAVE
TO BE MONITORED.

RIVER FORECAST POINTS WHERE FLOOD WARNINGS ARE STILL IN EFFECT AS
OF 400AM.

IN MA... CHARLES RIVER AT DOVER AT CREST AND REMAINS STEADY

THE AREAL FLOOD WARNING FOR SOUTHWESTERN WASHINGTON COUNTY IN RI
HAS BEEN CANCELLED AS THE LOWER PAWCATUCK RIVER HAS FALLEN BELOW
FLOOD STAGE.

REFER TO THE LATEST FLOOD STATEMENTS FOR SPECIFIC FORECASTS.
-- End Changed Discussion --

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
     ANZ254>256.

&&

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