000
FXUS61 KBOX 080757
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
357 AM EDT MON SEP 8 2008
.SYNOPSIS...
HIGH PRESSURE BUILDS OVER NEW ENGLAND TODAY AND SHIFTS OFFSHORE
TONIGHT AND TUESDAY. A COLD FRONT APPROACHES FROM THE GREAT LAKES
TUESDAY...CROSSING SOUTHERN NEW ENGLAND IN THE LATE AFTERNOON AND
EVENING. DRY...SEASONABLE WEATHER WILL RETURN WEDNESDAY AND THURSDAY
BEFORE A FRONTAL SYSTEM IMPACTS SOUTHERN NEW ENGLAND SOMETIME
BETWEEN FRIDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE IN PLACE TODAY WITH SUBSIDENCE AND DEWPOINTS IN THE
50S. SHOULD BE A PLEASANT DAY WITH WIDELY SCATTERED DIURNAL CUMULUS.
850 MB TEMPS 10-11C WOULD SUPPORT MAX TEMPS IN THE UPPER 70S AND
AROUND 80. WITH PLENTY OF SUNSHINE FOR MIXING TODAY...WE WILL EDGE
THE WARMER TEMPERATURES A LITTLE HIGHER TO BETTER COVER THE LOWER
80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
THE HIGH PRESSURE SETTLES OFFSHORE TONIGHT BUT CONTINUES TO MAINTAIN
SUBSIDENCE OVER SOUTHERN NEW ENGLAND. LOOK FOR MAINLY CLEAR SKIES AND
LIGHT WINDS...RESULTING IN RADIATIONAL COOLING. DEWPOINTS WILL
CONTINUE IN THE 50S...BUT EDGE UPWARD LATER IN THE NIGHT...SO THIS
WILL BE A GOOD TARGET RANGE FOR MIN TEMPS TONIGHT.
MODEL GUIDANCE SHOWS A WEAK FRONT SETTLING INTO NORTHERN NEW ENGLAND
OVERNIGHT. WITH THE UPPER FLOW WEST-SOUTHWEST THROUGH THE NIGHT THIS
FRONT WILL HAVE LITTLE CHANCE OF REACHING US. LOW PRESSURE MOVING UP
THE FRONT LATE AT NIGHT WILL ENCOURAGE WARM ADVECTION INTO NEW
ENGLAND WITH SOME CIRRUS OVERNIGHT.
TUESDAY LOOKS LIKE AN ACTIVE WEATHER DAY. LOW PRESSURE MOVING UP THE
ST LAWRENCE VALLEY SWINGS A COLD FRONT THROUGH THE NORTHEAST DURING
THE DAY. MINOR TIMING DIFFERENCES BUT ALL MODELS POINT TO COLD
FRONTAL PASSAGE DURING THE LATE AFTERNOON/EARLY NIGHT PERIOD. STRONG
WINDS ACROSS A DEEP LAYER ALOFT IN ADVANCE OF THIS FRONT WITH 45 TO 50
KNOTS FORECAST AT 850 MB AND 40 TO 60 KNOTS AT 500 MB. INSTABILITY
AVAILABLE WITH TOTAL TOTALS FORECAST IN THE LOWER 50S AND CAPE AROUND
1000 JOULES. PRECIPITABLE WATER VALUES ARE EXPECTED AT 1.5 TO 1.75
INCHES...MOIST ENOUGH FOR LOCALLY HEAVY DOWNPOURS BUT NOT THE
TORRENTIAL AMOUNTS WE SAW OVER THE WEEKEND WITH HANNA. THE PRIME
THREAT WOULD APPEAR TO BE WIND...ESPECIALLY STRAIGHT LINE WIND...IN
THE AFTERNOON AND EVENING. WE WILL GO WITH LIKELY POPS...APPEARING
FIRST IN THE WESTERN ZONES EARLY AFTERNOON AND SPREADING TO THE
EASTERN ZONES DURING THE AFTERNOON AND EVENING. THIS TIMING WILL BE
BASED ON A MIX OF GMOS...THE SHORT RANGE ENSEMBLES...AND CLIMATOLOGY.
WE WILL ALSO ADD EXTRA WORDING IN THE FORECAST TO THE CHANCE OF
THUNDERSTORMS.
850 MB TEMPS WILL BE AROUND 14C WHICH WOULD SUPPORT MAX TEMPS IN THE MID
80S. BUT WITH INCREASING CLOUDS FROM WEST TO EAST ESPECIALLY IN THE
AFTERNOON WE WILL CARVE MAX TEMPS BACK TO THE MID AND UPPER 70S IN
THE NORTHWEST AND LOWER 80S IN THE SOUTH AND EAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
TUESDAY NIGHT...WILL SEE THE COLD FRONT PUSH THROUGH THE REMAINDER
OF THE AREA OVERNIGHT...ALONG WITH THE SHOWERS AND THUNDERSTORMS.
EXPECT THE FRONT TO BE STRETCHED ALONG THE HIGHER TERRAIN OF CENTRAL
MASSACHUSETTS AND SOUTHERN NEW HAMPSHIRE AT 00Z. THE FRONT SHOULD
HAVE CLEARED ALL OF THE LAND ZONES INCLUDING THE CAPE AND ISLANDS BY
AROUND 09Z. WITH ALL THE MODELS SPITTING OUT QPF OVERNIGHT...EXPECT
THERE WILL BE RAIN THROUGH THE NIGHT ALONG AND AHEAD OF THE FRONT.
WITH THE LOSS OF DAYTIME HEATING...AND ANY RESULTANT INSTABILITY AM
UNSURE ABOUT CONTINUING THE MENTION OF THUNDER OVERNIGHT. THERE IS
STILL QUITE A BIT OF SHEAR /AROUND 50 KTS 0-6KM/ WHICH COULD BE
ENOUGH TO KEEP THUNDER IN THE FORECAST. WILL LEAVE THUNDER IN
OVERNIGHT BUT KEEP IT AS ISOLATED.
WEDNESDAY AND THURSDAY...HIGH PRESSURE BUILDS BACK INTO THE AREA
BEHIND THE FRONT. DRY...MORE AUTUMN-LIKE WEATHER IS EXPECTED...WITH
HIGH TEMPERATURES SLIGHTLY BELOW NORMAL.
FRIDAY THROUGH SUNDAY...ANOTHER SERIES OF FRONTS COULD MOVE THROUGH
SOUTHERN NEW ENGLAND. THERE IS SOME DISCREPANCY AMONGST THE MODELS
ON BOTH THE IMPACT OF A WARM FRONT FRIDAY NIGHT AND THE TIMING OF
THE COLD FRONT SATURDAY OR SUNDAY. WITH HIGH PRESSURE REMAINING
JUST OFFSHORE FRIDAY...THE WARM FRONT MAY HAVE TROUBLE MAKING IT TO
SOUTHERN NEW ENGLAND UNTIL LATER FRIDAY EVENING. THE COLD FRONT
SHOULD MOVE THROUGH BETWEEN SATURDAY MORNING AND SUNDAY AFTERNOON.
THERE IS STILL QUITE A BIT OF DIFFERENCE IN THE MODELS ON THIS. AT
THIS POINT...WILL ONLY MAKE SMALL ADJUSTMENTS TO THE GRIDS FOR THESE
DAYS SINCE THE PICTURE REMAINS SO UNCLEAR.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
PATCHY MVFR IN FOG THROUGH 11Z THIS MORNING...OTHERWISE VFR TODAY.
CONTINUED VFR TONIGHT EXCEPT MVFR IN PATCHY FOG LATE AT NIGHT.
TUESDAY WILL MAINLY BE VFR. SHOWERS AND THUNDERSTORMS ARE LIKELY IN
THE AFTERNOON AND EVENING...WITH EPISODES OF MVFR/IFR CIGS AND VSBYS
AT ANY SITES THEY MOVE OVER. THE THUNDERSTORMS WILL HAVE A GOOD POTENTIAL
FOR PRODUCING STRONG STRAIGHT LINE WINDS AND AS SUCH SHOULD BE GIVEN
EXTRA RESPECT BY AVIATION INTERESTS.
OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
TUESDAY NIGHT...MVFR IN SHOWERS AND THUNDERSTORMS AS THE FRONT
FINISHES MOVING THROUGH SOUTHERN NEW ENGLAND. A GRADUAL RETURN TO
VFR FROM THE WESTERN TERMINALS BEFORE MIDNIGHT...TO ALONG THE CAPE
AND ISLANDS NEAR SUNRISE.
WEDNESDAY THROUGH FRIDAY...VFR.
FRIDAY NIGHT...VFR WITH SOME MVFR POSSIBLE IN SHOWERS ASSOCIATED
WITH A WARM FRONT.
SATURDAY...DEPENDING ON THE TIMING OF THE FRONT...POSSIBLY MVFR IN
SHOWERS AND POSSIBLE THUNDERSTORMS. OTHERWISE...VFR.
&&
.MARINE...
STILL 10 FOOT SEAS OFF NANTUCKET AND 5 FOOT SEAS AT MONTAUK. SO WHILE
WINDS HAVE DIMINISHED FOR THE WHILE...ROUGH SEAS WILL CONTINUE TO BE
A PROBLEM TODAY. WE WILL CONTINUE A SMALL CRAFT ADVISORY FOR
SEAS...ENDING FROM NORTH TO SOUTH DURING MIDDAY AND THE AFTERNOON.
ALL QUIET TONIGHT WITH LIGHT WINDS AND SEAS.
INCREASING SOUTH TO SOUTHWEST GRADIENT WILL BRING WINDS UP...WITH
POTENTIAL FOR GUSTS OF 25 TO 30 KNOTS IN THE AFTERNOON. A COLD FRONT
WILL BRING THUNDERSTORMS TO THE WATERS LATE IN THE DAY CONTINUING
INTO THE EVENING. THESE THUNDERSTORMS WILL HAVE A POTENTIAL FOR
STRONG STRAIGHT LINE WINDS.
OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...
TUESDAY NIGHT...SMALL CRAFT CRITERIA LIKELY AS A COLD FRONT SWEEPS
ACROSS THE COASTAL WATERS.
WEDNESDAY...WINDS AND WAVES WILL FALL BELOW SMALL CRAFT CRITERIA
WEDNESDAY AFTERNOON.
THURSDAY THROUGH FRIDAY...WINDS AND WAVES WILL REMAIN BELOW SMALL
CRAFT CRITERIA.
FRIDAY NIGHT THROUGH SATURDAY...WINDS AND WAVES WILL INCREASE TO
SMALL CRAFT CRITERIA WITH THE APPROACH OF ANOTHER FRONTAL SYSTEM.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON EDT TODAY
FOR ANZ235-254.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM EDT THIS
AFTERNOON FOR ANZ255.
&&
$$
SYNOPSIS...WTB/RLG
NEAR TERM...WTB
SHORT TERM...WTB
LONG TERM...RLG
AVIATION...WTB/RLG
MARINE...WTB/RLG
