AP-CT--BOS-CT N Area Forecast Discussion, CT
000
FXUS61 KBOX 151309
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
909 AM EDT WED JUL 15 2015
.SYNOPSIS...
A COLD FRONT WILL BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
MAINLY THIS AFTERNOON INTO THE EARLY EVENING HOURS. LOCALLY HEAVY
RAINFALL IS POSSIBLE ESPECIALLY TO THE SOUTH OF THE MASSACHUSETTS
TURNPIKE. CANADIAN HIGH PRESSURE PROVIDES DRY AND SLIGHTLY COOLER
THAN NORMAL WEATHER THURSDAY AND FRIDAY. WARMER WEATHER IS LIKELY
NEXT WEEKEND INTO EARLY NEXT WEEK...BUT WITH AN INCREASED RISK FOR
SHOWERS OR THUNDERSTORMS EACH DAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
***SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MAY RESULT IN SOME
POOR DRAINAGE STREET FLOODING SOUTH OF MA TURNPIKE THIS
AFTERNOON AND EARLY THIS EVENING***
9 AM UPDATE...
VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS CONFIRM STRATUS
CONTINUES TO BURN OFF AND LIFT INTO A STRATOCU DECK ESPECIALLY
AWAY FROM THE COASTLINE. FRONTAL BOUNDARY HAS ADVANCED AS FAR
SOUTHEAST AS RI /SFZ-SMITHFIELD/...BID AND SOUTHEAST MA WITH GHG
/MARSHFIELD/ ALREADY WITH A WIND SHIFT TO THE N-NW! ALTHOUGH
DESTABILIZATION WILL TAKE PLACE DESPITE WIND SHIFT AS SURFACE DEW
PTS STILL IN THE 60S ON THE COOLER SIDE OF THE BOUNDARY. HOWEVER
THE RACE WILL BE ON BETWEEN DRIER AIR FROM THE NW /ALBANY N WND
G22KT/ AND WARM SOUPY AIRMASS CURRENTLY OVER THE REGION. FRONTAL
BOUNDARY SHOULD SLOW DOWN AS SURFACE WAVE INTENSIFIES OFF THE NJ
COAST. IS THIS REALLY A MID JULY PATTERN?
THIS AFTERNOON AND EARLY EVENING FORECAST WILL HINGE ON CONVECTION
OVER NJ...SPECIFICALLY DOES THIS CONVECTION ROB DEEP MOISTURE AND
INSTABILITY FROM ADVECTING NORTHEAST INTO SOUTHERN NEW ENGLAND?
HALF OF THE MODEL GUIDANCE SAYS YES WHILE THE OTHER HALF OF THE
GUIDANCE INDICATES A SECOND AREA OF CONVECTION FIRING OVER CT/RI
AND SOUTHEAST MA. WILL JUST HAVE TO SEE HOW WELL 12Z MODELS
SIMULATE NJ CONVECTION AND WATCH SATELLITE AND RADAR TRENDS HOUR
BY HOUR. THUS LOW CONFIDENCE FORECAST BUT HIGH IMPACT POTENTIAL
WITH VERY RAINFALL AND LOCALIZED FLOODING IN THE I95 CORIDOR
POSSIBLY. THIS IS WHERE THE GREATER INSTABILITY WILL LIKELY EXIST.
TIMING COULD IMPACT THE LATE DAY COMMUTE. THUS NOT MUCH CHANGE
FROM PREVIOUS FORECAST BUT STAY TUNED FOR ADDITIONAL DETAILS.
PREVIOUS DISCUSSION...
BY LATE MORNING AND ESPECIALLY THIS AFTERNOON A SHORTWAVE WILL
APPROACH FROM THE SOUTHWEST. AT THE SAME TIME...A COLD FRONT WILL
BE DROPPING DOWN FROM THE NORTHWEST. THIS WILL RESULT IN SCATTERED
SHOWERS AND A FEW THUNDERSTORMS TO INCREASE IN AREAL COVERAGE LATE
THIS MORNING AND ESPECIALLY THIS AFTERNOON. BULK OF ACTION WILL BE
SOUTH OF THE MA TURNPIKE FROM MID AFTERNOON INTO THE EARLY EVENING
HOURS.
SEVERE WEATHER POTENTIAL IS RATHER LOW GIVEN VERY WEAK WIND FIELDS
AND LIMITED INSTABILITY. HOWEVER...WE SHOULD BE ABLE TO MUSTER
CLOSE TO 1000 J/KG OF CAPE. THIS WILL COMBINED WITH PWATS AROUND 2
INCHES TO BRING THE POTENTIAL OF LOCALLY HEAVY RAINFALL AND BRIEF
POOR DRAINAGE STREET FLOODING WITH ANY OF THE STRONGER ACTIVITY.
THE HIGHEST RISK FOR THIS IS AREAS SOUTH OF THE MA TURNPIKE...WHERE
THEY WILL BE CLOSER TO THE SHORTWAVE ALONG WITH BETTER INSTABILITY.
VERY WEAK WIND FIELDS ARE ALSO A CONCERN SINCE ANY ACTIVITY THAT
DEVELOPS WILL HAVE THE POTENTIAL TO MOVE RATHER SLOWLY OVER A
PARTICULAR LOCATION.
WHILE POCKETS OF BRIEF POOR DRAINAGE STREET FLOODING ARE A DECENT
BET...IT REMAINS UNCERTAIN IF AN ISOLATED LOCATION OR TWO ENDS UP
WITH A PERIOD OF MORE SIGNIFICANT URBAN FLOODING. SOME LIMITING
FACTORS FOR THAT ARE THAT LOW LEVEL FORCING IS NOT THAT IMPRESSIVE
AND BETTER INSTABILITY WILL RESIDE TO OUR SOUTH. HOWEVER...SOME OF
OUR MESOSCALE MODELS ARE SHOWING BULLSEYES OF 2 TO 3.50 INCHES OF
RAIN ACROSS PORTIONS OF NORTHERN CT/RHODE ISLAND AND SOUTHEAST MA.
WHILE WE WOULD LIKE TO SEE THE GLOBAL MODELS SHOWING A LITTLE BETTER
SIGNAL TO HAVE MORE CONFIDENCE IN THIS SCENARIO...THERE IS SOME
REASON TO BE CONCERNED. APPEARS WE MAY BE DEALING WITH SOME TYPE OF
SEA BREEZE FRONT OUT AHEAD OF THE MAIN COLD FRONT. IF THIS COMES TO
FRUITION...IT COULD PROVIDE SOME FOCUS FOR A VERY LOCALIZED AREA OR
TWO RECEIVING 2+ INCHES OF RAIN IN AN HOUR OR LESS. NO ACTION WILL
BE TAKEN AT THIS TIME...BUT BASED ON HOW THINGS LOOK LATER THIS
MORNING THE NEXT SHIFT MAY WANT TO ISSUE A SPECIAL WEATHER STATEMENT
OR PERHAPS EVEN A VERY LOCALIZED FLASH FLOOD WATCH IF CONFIDENCE IS
HIGH ENOUGH.
HIGH TEMPS WILL RANGE FROM THE UPPER 70S TO THE MIDDLE 80S AND IT
WILL BE RATHER HUMID.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EARLY THIS EVENING
SHOULD COME TO AN END BY LATE EVENING ACROSS THE SOUTHEAST NEW
ENGLAND COAST. THIS THE RESULT OF A FAIRLY STRONG COLD FRONT FOR
JULY STANDARDS PUSHING SOUTHEAST OF THE REGION. MUCH DRIER AND
COOLER AIR WILL WORK INTO THE REGION. LOW TEMPS BY DAYBREAK
THURSDAY WILL BE IN THE MIDDLE TO UPPER 50S ACROSS MUCH OF THE
INTERIOR...TO THE LOWER TO MIDDLE 60S ON THE COASTAL PLAIN.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* DRY AND COOLER ON THURSDAY AND FRIDAY
* UNSETTLED WEATHER FOR THE WEEKEND
* WARMING TREND THIS WEEKEND INTO NEXT WEEK
OVERVIEW AND MODEL PREFERENCES...
SYNOPTIC SCALE FEATURES REMAIN IN FAIRLY GOOD AGREEMENT THROUGH
THE LONG TERM. THE UPPER LVL VORTEX ACROSS NRN CANADA WILL
ACTUALLY RETROGRADE SOMEWHAT AS IT PHASES WITH ANOTHER WAVE MOVING
OUT OF THE ALASKAN REGION. THIS ORIENTS THE ZONAL FLOW ACROSS THE
NRN CONUS /AND BY PROXY...SNE/ FROM W-E TO MORE OF A SW TO NE
DIRECTION. THIS MEAN-JET IS ON THE PERIPHERY OF A BUILDING
SUBTROPICAL RIDGE ACROSS THE SE CONUS. THIS SHIFT IN THE FLOW
PATTERN ALOFT HAS TWO CONSEQUENCES...IT ALLOWS FOR A CONDUIT OF
SEVERAL WEAK SHORTWAVES WHICH WILL MOVE ACROSS THE REGION FROM
DURING THE EXTENDED AND ALSO ALLOWS MORE DESTABILIZED AIR...AND
POSSIBLY EVEN AN EML FROM THE WRN CONUS TO MOVE ACROSS THE AREA.
THEREFORE...EXPECT THE DRY LATE WEEK PERIOD TO TRANSITION TO A
WETTER AND MORE UNSETTLED PERIOD FROM THE LATTER HALF OF THE
WEEKEND INTO EARLY NEXT WEEK. MODERATING TEMPERATURES ARE EXPECTED
THROUGH THE LONG TERM...STARTING MAINLY BELOW NORMAL THEN TRENDING
ABOVE BY EARLY NEXT WEEK. A BLEND OF GUIDANCE SEEMS REASONABLE
GIVEN THE LARGER SCALE AGREEMENT. SLIGHT ADJUSTMENTS WILL BE MADE
AS NEEDED FOR SENSIBLE WX.
DETAILS...
THU INTO FRI NIGHT...
HIGH PRES BUILDS ACROSS THE REGION THROUGH THE PERIOD WITH MAINLY
DRY WX. TEMPS ON THU WILL BE MAINLY BELOW NORMAL...ESPECIALLY NEAR
THE E COAST WHERE 10-20 KT N-NE WINDS ASSISTED BY SEA BREEZE WILL
KEEP HIGHS ONLY IN THE LOW 70S. WARMER FURTHER W...BUT H85 TEMPS
ARE ONLY ABOUT +12C...WHICH WOULD CORRESPOND TO NEAR OR SLIGHTLY
BELOW NORMAL HIGHS. BY FRI...HIGHS WILL REBOUND A BIT TO NEAR
NORMAL...ALTHOUGH LIGHT FLOW SUGGESTS SEA BREEZES ONCE AGAIN AT
THE COASTLINES.
SAT...
STRONG WAVE/COLD POOL WHICH APPEARS TO BE THE REMNANT OF A NRN
PLAINS MCS WILL BE APPROACHING THE REGION FROM THE W. DEVELOPING
BAROCLINICITY AS IT APPROACHES THE IMPACT ON SRN NEW ENGLAND WILL
BE WHERE THE WARM FRONTAL BOUNDARY ENDS UP. BEST CHANCES APPEAR TO
BE ACROSS THE W...BUT THE INSTABILITY GRADIENT MAINLY TO THE W AND
SW. THEREFORE...EXPECT MOST OF THE CONVECTION TO BE RIGHT TURNING
AWAY FROM THE REGION. STILL...ENOUGH UNCERTAINTY WITH THIS UPDATE
TO INCLUDE A RISK FOR T-STORMS MAINLY IN THE W. HIGHEST RISK IS
HEAVY RAIN THANKS TO MODERATELY HIGH PWATS. IN ANY
CASE...AFTERNOON/EVENING SHOWERS ARE LIKELY EVERYWHERE AS THE
UPPER LVL WAVE CONTINUES IT/S PROGRESSION TO THE E.
SUN INTO MON...
THE WARM FRONT WILL MAKE A SLOW ATTEMPT AT PROGRESSING NE AS THE
UPPER LVLS TEND TOWARD RIDGING FOLLOWING THE FIRST WAVE PASSAGE ON
SAT. WITH MODERATE PWAT AIR /AVERAGING AROUND 1.5 INCHES/ AND THE
SLOW MOVING /POSSIBLY EVEN STALLING/ FRONT IN THE
VICINITY...SUSPECT THAT IN SPITE OF THE UPPER LVL RIDGE...THE RISK
FOR DIURNALLY DRIVEN CONVECTIVE SHOWERS/STORMS ARE POSSIBLE EACH
DAY. THE T-STORM RISK WILL DEPEND MOSTLY ON WHERE THE FRONT STALLS
/LATEST GFS ACTUALLY PUSHES IT BACK W AS A BACKDOOR COLD FRONT ON
MON/. WILL GO WITH MAINLY -SHRA...BUT INCLUDE A LOW END CHANCE OF
T-STORMS AS WELL. ALTHOUGH H85 TEMPS INCREASE TO NEAR +15C BY THIS
POINT...ACTUAL TEMPS WILL BE DEPENDENT ON CLOUD COVER AND FRONTAL
BOUNDARY MOVEMENT.
TUE AND WED...
AFTER A BRIEF PERIOD IN THE WARM SECTOR POSSIBLE A SECONDARY
UPPER LVL WAVE WILL APPROACH FROM THE W WITH AN ASSOCIATED COLD
FRONT. THIS WILL HAVE TO BE WATCHED AS GUIDANCE INDICATES THE
POSSIBILITY OF A REMNANT EML AND FAIRLY DESTABILIZED COLUMN WITH
WARM LOW LVL TEMPS AND REASONABLY HIGH MOISTURE. STILL TIMING
ISSUES AND OVERALL COLUMN STATIC STABILITY TO WORK OUT...BUT THIS
PERIOD MAY NEED TO BE WATCHED.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /TODAY AND TONIGHT/...
9 AM UPDATE...NOT MUCH CHANGE FROM 12Z TAFS. VFR AWAY FROM THE
COASTLINE WITH SLOWLY IMPROVING CONDITIONS ALONG THE COAST.
GREATEST RISK FOR HEAVY AFTERNOON SHOWERS AND THUNDERSTORMS WILL
BE ACROSS CT/RI AND SOUTHEAST MA. EARLIER DISCUSSION BELOW.
TODAY...MODERATE CONFIDENCE.
CONDITIONS ARE ALREADY IMPROVING TO VFR AND EXPECT THIS TREND TO
CONTINUE AWAY FROM THE SOUTH COAST THIS MORNING. LOW CLOUDS WITH
MAINLY MVFR /ALTHOUGH PERIODIC IFR NOT OUT OF THE QUESTION/ MAY
HANG IN MOST OF THE DAY ESPECIALLY S OF A WST-TAN-PYM LINE.
OTHERWISE...AFTERNOON SHOWERS AND THUNDERSHOWERS POSSIBLE
ESPECIALLY THIS AFTERNOON AND ESPECIALLY AT TERMINALS S OF THE
MASS PIKE. LOCALLY HEAVY RAINFALL WITH BRIEF IFR CONDITIONS
POSSIBLE.
TONIGHT...HIGH CONFIDENCE IN TRENDS...LOWER CONFIDENCE IN EXACT
TIMING.
EVENING MVFR/IFR CONDITIONS IN LEFTOVER FOG/SHOWERS/T-STORMS WILL
GRADUALLY GIVE WAY TO CLEARING AND IMPROVING CONDITIONS DURING THE
OVERNIGHT HOURS WITH VFR EXPECTED PRETTY MUCH EVERYWHERE BY 04Z
OR MIDNIGHT LOCAL. WINDS WILL BE SHIFTING MAINLY TO THE N...WITH
GUSTS 20-30 KT POSSIBLE ESPECIALLY ACROSS E MA AND RI LATE.
KBOS TERMINAL...HIGH CONFIDENCE FOR VFR NOW THAT LOW CLOUDS HAVE
CLEARED. SCATTERED SHOWERS AND PERHAPS AN ISOLATED THUNDERSTORM
WILL BE IN THE VICINITY OF THE TERMINAL THIS AFTERNOON.
KBDL TERMINAL...EXPECT SOME IMPROVEMENT FROM THE MVFR CIGS LATER
THIS MORNING. SCATTERED SHOWERS AND PERHAPS AN ISOLATED
THUNDERSTORM WILL BE IN THE VICINITY OF THE TERMINAL THIS
AFTERNOON.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THU THROUGH FRI....HIGH CONFIDENCE. MAINLY VFR. NORTHERLY WINDS
APPROACH 20-25 KT ESPECIALLY OVER E MA TERMINALS ON THU...SEA
BREEZES LIKELY WITH WEAKER FLOW ELSEWHERE FRI.
SAT INTO SUNDAY...MODERATE CONFIDENCE.
MAINLY VFR. COULD SEE SCT MVFR IN ISO -SHRA/-TSRA. HIGHEST
CONFIDENCE IS ACROSS WESTERN TERMINALS. SOME FOG POSSIBLE DURING
THE OVERNIGHTS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /TODAY THROUGH WEDNESDAY/...
***NORTHEAST WIND GUSTS OF 20 TO 30 KNOTS EXPECTED LATE THIS EVENING
AND INTO THE FIRST HALF OF THURSDAY***
TODAY...MODERATE TO HIGH CONFIDENCE. WEAK PRESSURE GRADIENT WILL
KEEP WINDS BELOW SMALL CRAFT ADVISORY THRESHOLDS. HOWEVER...SMALL
CRAFT ADVISORIES GO INTO EFFECT THIS MORNING FOR OUR SOUTHERN WATERS
FOR 3 TO 6 FOOT SOUTHERLY SWELL. BY LATE AFTERNOON AND EARLY
EVENING...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL LIKELY
AFFECT THE WATERS NEAR THE SOUTH COAST.
TONIGHT...MODERATE TO HIGH CONFIDENCE. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS EXPECTED THIS EVENING ACROSS OUR SOUTHERN
WATERS. IN ADDITION...AREAS OF FOG MAY ALSO REDUCE VISIBILITIES
DURING THE FIRST HALF OF THE NIGHT. OTHERWISE...STRONG COLD FRONT
FOR JULY STANDARDS WILL BRING NORTHEAST WIND GUSTS OF 20 TO 30 KNOTS
BY LATE EVENING. SMALL CRAFT HEADLINES POSTED FOR ALL WATERS EXCEPT
BOSTON HARBOR AND NARR BAY.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THU...HIGH CONFIDENCE.
WITH HIGH PRES APPROACHING FROM THE W...EXPECT N-NE WIND GUSTS
APPROACHING 25 KT AT TIMES THROUGH THE DAY. SEAS WILL REMAIN
ELEVATED...5-6 FT ON THE OCEAN WATERS. THEREFORE...SMALL CRAFT
ADVISORIES WILL BE EXTENDED INTO THU...AND MAY NEED TO LINGER INTO
THU NIGHT UNTIL SEAS ARE ALLOWED TO SUBSIDE.
FRI AND SAT...HIGH CONFIDENCE.
MAINLY QUIET BOATING WEATHER UNDER HIGH PRES. ALTHOUGH A FEW
SHOWERS OR T-STORMS ARE POSSIBLE ON SAT.
SUN...MODERATE CONFIDENCE.
SHOWERS AND STORMS MAY LINGER. WIND DIRECTIONS WILL DEPEND ON THE
LOCATION OF A FRONT BY THIS TIME. HOWEVER...EXPECT WINDS AND SEAS
TO GENERALLY REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM EDT
THURSDAY FOR ANZ231>234-250-251.
SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 4 PM EDT
THURSDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 8 PM EDT
THURSDAY FOR ANZ254.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THURSDAY FOR ANZ255-256.
&&
$$
SYNOPSIS...FRANK/DOODY
NEAR TERM...FRANK/NOCERA/DOODY
SHORT TERM...FRANK
LONG TERM...DOODY
AVIATION...FRANK/NOCERA/DOODY
MARINE...FRANK/DOODY
Delivered by Weather Underground Inc. Wed Jul 15 2015 9:09AM EDT