-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBOX 180544
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
144 AM EDT SAT MAY 18 2013

.SYNOPSIS...
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HIGH PRESSURE PROVIDES DRY AND SEASONABLE WEATHER FOR MUCH OF THE
WEEKEND. AN APPROACHING WARM FRONT WILL INCREASE THE CHANCE OF
RAIN SUNDAY NIGHT INTO MONDAY. THE FRONT WILL LIFT NORTH OF THE
AREA BY TUESDAY THEN STALL. WEAK WAVES OF LOW PRESSURE WILL MOVE
ALONG THE FRONT LATE TUESDAY THROUGH AT LEAST THURSDAY...BRINGING
WARM...HUMID CONDITIONS WITH A CONTINUED THREAT OF SHOWERS AND
POSSIBLY A RUMBLE OF THUNDER.
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&&

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

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145 AM UPDATE...

TRANQUIL WEATHER EARLY THIS MORNING ACROSS SOUTHERN NEW ENGLAND AS
HIGH PRESSURE BUILDS INTO THE AREA FROM THE NORTH. WARM ADVECTION
CLOUDS STREAMING IN FROM NY STATE INTO WESTERN MA/CT AND RI
APPEARS THIN ENOUGH NOT TO IMPACT TEMPS FROM FALLING. GIVEN THE
LIGHT WINDS/DRY AIRMASS AND ONLY A THIN CANOPY OF MID/HIGH CLOUDS
TEMPS SHOULD FALL CLOSE TO DEW PT VALUES. THEREFORE COULD HAVE
SOME PATCHY FROST ACROSS INTERIOR SECTIONS AND POSSIBLY EVEN MVY.
OTHERWISE FORECAST IS STRAIGHT FORWARD.
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&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
SATURDAY...
HIGH PRES REMAINS IN CONTROL AS IT STRENGTHENS JUST E OF SNE. RH
CROSS SECTIONS SUGGEST ANOTHER PERIOD OF SCT-BKN CU DEVELOPING IN
SNE. THERE IS A VERY LOW PROB OF AN ISOLD SHOWER OR SPRINKLE FROM
S NH THROUGH E MA CLOSEST TO THE COLD POOL OVER MAINE...BUT IT IS
LIKELY TO REMAIN DRY ALL DAY. WE HAVE SLIGHT CHC POPS IN THIS
REGION. USED A BLEND OF TRADITIONAL MOS AND BIAS CORRECTED MOS FOR
MAX TEMPS WHICH YIELDS 70-75 DEGREES AWAY FROM THE IMMEDIATE
COAST. SEABREEZES ARE LIKELY TO DEVELOP GIVEN LIGHT WINDS IN THE
BOUNDARY LAYER WHICH WILL HOLD TEMPS IN THE 60S NEAR THE COAST.

SATURDAY NIGHT...
AN ISOLD SHOWER/SPRINKLE COULD SPILL INTO THE EVENING ACROSS NE
ZONES...OTHERWISE DRY CONDITIONS AS HIGH PRES BUILDS E OF NEW
ENG. THERE IS A BIT MORE MOISTURE IN THE COLUMN WHICH SUPPORTS
MORE CLOUDS SAT NIGHT. A MILDER NIGHT THAN TONIGHT WITH MINS
MOSTLY IN THE 40S...EXCEPT CLOSE TO 50 IN THE URBAN AREAS.

&&

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

 * CHANCE OF SHOWERS SUNDAY NIGHT INTO MONDAY
 * WARM AND MORE HUMID CONDITIONS WITH PERIODS OF SHOWERS FROM
   LATE TUESDAY THROUGH AT LEAST THURSDAY

OVERVIEW AND MODEL PREFERENCES...
NOTING AN AMPLIFIED BUT PROGRESSIVE PATTERN AS UPPER LEVEL RIDGE
BUILDS ACROSS THE EASTERN U.S. ON SUNDAY. THE UPPER FLOW CONTINUES
TO SHOW SIGNS OF BLOCKING AROUND THE CENTRAL U.S. AS CUTOFF H5
LOW DEVELOPS ACROSS THE UPPER PLAINS STATES AND STALLS BY MID
WEEK. UPPER FLOW ACROSS THE NORTHEAST FLATTENS OUT AROUND LATE
MONDAY OR TUESDAY AS A WARM FRONT APPROACHES. MOST OF THE MEDIUM
RANGE MODELS IN GOOD AGREEMENT IN STALLING THIS FRONT...BUT BIG
QUESTION IS WHERE THIS WILL OCCUR. AT THIS POINT...LOOKS LIKE
CONDITIONS BECOME WARMER AND MORE HUMID STARTING MONDAY THROUGH
LATE NEXT WEEK. WEAK WAVES OF LOW PRES MOVE ALONG THE STALLED
FRONT...SO WILL ALSO SEE SCT SHOWERS FROM TIME TO TIME BUT EXACT
TIMING IS UNCERTAIN. BEYOND LATE WEDNESDAY...MODEL SOLUTIONS WIDEN
OUT ON TIMING THE MOVEMENT OF SURFACE FEATURES AS WELL AS THE
PROGRESSION OF THE CUTOFF SYSTEM.

USED A BLEND OF THE 12Z GFS/00Z ECMWF FOR MOST OF THE PERIOD...
BUT DID START TO LEAN MORE TOWARD THE GFS/EC ENSEMBLES LATE IN THE
PERIOD DUE TO THE TIMING ISSUES.

DETAILS...

SUNDAY-MONDAY...HIGH PRES CENTER WILL SHIFT S ACROSS EASTERN MAINE
AND ACROSS THE WESTERN ATLC ON SUNDAY BRINGING SE-S WINDS BUT
MAINLY DRY CONDITIONS EARLY IN THE DAY. WILL SEE DRY CONDITIONS TO
START OUT BUT CLOUDS WILL INCREASE AS MOISTURE WORKS IN. WARM
FRONT WILL APPROACH OUT OF THE MID ATLC AS THE HIGH SHIFTS E
DURING SUN NIGHT. UPPER LEVEL FLOW BACKS FROM NW TO W DURING
MONDAY INTO MONDAY NIGHT AS THE WARM FRONT STARTS TO STALL EITHER
OVER N MA/S NH OR A BIT FURTHER N. NOTING A WEAK WAVE STARTS TO
FORM ON THE FRONT LATE ACROSS THE EASTERN LAKES/NY STATE. THIS
WILL KEEP A CHANCE FOR SHOWERS FROM SUNDAY NIGHT THROUGH MONDAY
NIGHT.

TUESDAY-THURSDAY...UPPER LEVEL PATTERN FLATTENS OUT ACROSS THE
NORTHEAST U.S. AS THE FRONT HANGS UP SOMEWHERE ACROSS CENTRAL NEW
ENGLAND. WEAK WAVES OF LOW PRES EJECT OUT OF THE UPPER LEVEL
SYSTEM ACROSS THE CENTRAL U.S. AND WORK ALONG THIS FRONT. THIS
WILL BRING PERIODS OF SHOWERY CONDITIONS. FOR NOW...HAVE KEPT THIS
FRONT MAINLY N OF THE REGION WITH GOOD INSTABILITY IN PLACE.
TOTAL TOTALS HEAD UP TO THE LOWER-MID 50S...LIFTED INDICES ARE
WELL BELOW ZERO AS WELL. SO...DEPENDING UPON WHETHER ANY SUN
BREAKS THROUGH THE CLOUDS...COULD SEE WIDELY SCT THUNDER FROM LATE
MORNING INTO THE EVENING HOURS EACH DAY. TUESDAY AND WEDNESDAY
LOOK PRETTY MILD WITH HIGHS IN THE MID 70S TO AROUND 80 ALONG WITH
INCREASING DEWPTS.

MODEL TIMING IS SUSPECT BY THURSDAY NIGHT IN TRYING TO MOVE A COLD
FRONT THROUGH THE REGION.

FRIDAY...LOW CONFIDENCE ON THIS PORTION OF THE FORECAST...BUT DID
LEAN TOWARD WPC GUIDANCE IN SLOWLY BRINGING A COLD FRONT ACROSS
THE REGION WITH HIGH PRES BUILDING IN FROM CENTRAL CANADA.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
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FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH SUNDAY NIGHT/...MODERATE CONFIDENCE.

HIGH CONFIDENCE FOR VFR CONDITIONS INTO SUN MORNING BUT THEN LOWER
CONFIDENCE ON TIMING OF MVFR CONDITIONS AND SHOWERS LATER SUN.
ISOLATED AFTN SHOWER POSSIBLE TODAY OTHERWISE DRY INTO SUN AM.
THEN CHANCES INCREASE LATER SUN FROM WEST TO EAST AS WARM FRONT
APPROACHES FROM THE SOUTHWEST. SEA BREEZE DEVELOPS EARLIER TODAY
THAN FRIDAY. MODEL GUIDANCE....BASICALLY FOLLOWED AN EVEN BLEND OF
THE 00Z NAM AND GFS.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEABREEZE DEVELOPS EARLIER
TODAY THAN FRI. ISOLATED AFTN/EARLY EVENING SHOWER. OTHERWISE DRY
WEATHER PREVAILS INTO SUNDAY.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF. LOW RISK OF AN ISOLATED
SHOWER THIS AFTERNOON/EARLY EVENING. THEN HIGHER CHANCES OF RAIN MID
TO LATE AFTN SUNDAY.

OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...

SUNDAY NIGHT THROUGH WEDNESDAY....MVFR-IFR CIGS/VSBYS IN PERIODS
OF LIGHT SHOWERS. PATCHY LATE NIGHT/EARLY MORNING FOG EACH DAY
ESPECIALLY ALONG S COAST. LOW PROB OF THUNDER LATE MORNING
THROUGH THE EVENING MON- WED. MODERATE CONFIDENCE.
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&&

.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.

LIGHT WINDS AND SEAS TROUGH THE PERIOD AS HIGH PRES BUILDS OVER
THE WATERS.

OUTLOOK...SUNDAY THROUGH WEDNESDAY...

SUNDAY...HIGH CONFIDENCE. LIGHT SE WINDS TO START BECOME S AND
PICK UP BUT REMAIN BELOW SMALL CRAFT CRITERIA. SEAS ALSO REMAIN
BELOW SMALL CRAFT.

SUNDAY NIGHT THROUGH TUESDAY...MODERATE CONFIDENCE. S-SW WINDS
PICK UP WITH GUSTS TO 20-25 KT HIGHEST ACROSS THE SOUTHERN OUTER
WATERS. SEAS BUILD TO 5-7 FT...HIGHEST ON THE OUTER WATERS.

WEDNESDAY...MODERATE CONFIDENCE. WINDS DIMINISH BUT REMAINING
GENERALLY S-SW. SEAS REMAIN AOA 5 FT ON THE SOUTHERN OUTER
WATERS.

&&

.FIRE WEATHER...
DRY CONDITIONS WILL CONTINUE THIS WEEKEND. MINIMUM RELATIVE
HUMIDITIES SATURDAY WILL BE BELOW 30 PERCENT IN THE INTERIOR BUT
WINDS WILL BE RATHER LIGHT. ON SUNDAY...HIGHER RELATIVE
HUMIDITIES ARE EXPECTED...FROM 45 TO 60 PERCENT WITH S-SE WINDS
AROUND 10 MPH.

&&

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

&&

$$
SYNOPSIS...KJC/EVT/THOMPSON
NEAR TERM...KJC/NOCERA/EVT
SHORT TERM...KJC
LONG TERM...EVT
AVIATION...NOCERA/EVT
MARINE...KJC/EVT
FIRE WEATHER...STAFF