Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 171904
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
304 PM EDT FRI MAY 17 2013

.SYNOPSIS...
HIGH PRESSURE PROVIDES DRY AND SEASONABLE WEATHER FOR MUCH OF THE
WEEKEND. AN APPROACHING WARM FRONT WILL THEN INCREASE THE CHANCE
OF RAIN FROM LATE SUNDAY INTO MONDAY. THE FRONT LIFTS NORTH OF THE
AREA AROUND TUE OF NEXT WEEK YIELDING WARM...MORE HUMID AND
SHOWERY WEATHER MUCH OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AREA OF CU ACROSS EASTERN NEW ENG WILL GRADUALLY ERODE THROUGH
THIS EVENING. OTHERWISE...HIGH PRES WILL BE ACROSS NEW ENG
TONIGHT WITH MOCLEAR SKIES AND LIGHT WINDS. GOOD RADIATIONAL
COOLING WILL RESULT IN A CHILLY NIGHT WITH DROPPING IN THE THE
MID/UPPER 30S IN COLDER SPOTS OF NW MA AND SW NH WITH POSSIBLY A
TOUCH OF FROST. ELSEWHERE...MIN TEMPS WILL RANGE THROUGH THE 40S.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
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 THROUGH THURSDAY/...
HIGHLIGHTS...

 * CHANCE OF RAIN LATE IN THE WEEKEND
 * TREND TOWARD WARMER/MORE HUMID AND SHOWERY WEATHER NEXT WEEK

LOW CONFIDENCE FORECAST ON THE DETAILS NEXT WEEK AS MODELS ARE NOW
TRENDING TOWARD A MORE AMPLIFIED/BLOCK PATTERN...WITH THE NORTHERN
STREAM BECOMING MORE DOMINANT WITH TIME ACROSS SOUTHEAST CANADA AND
THE NORTHEAST. THE QUESTION THEN BECOMES HOW MUCH DOES THE NORTHERN
STREAM ERODE THE SUBTROPICAL RIDGE ALONG THE EASTERN SEABOARD NEXT
WEEK? THIS WILL DETERMINE THE LOCATION AND SOUTHEAST PROGRESSION OF
A FRONTAL BOUNDARY...WHICH WILL BE CRITICAL IN DETERMINING
TEMPERATURES AND PROBABILITY OF PRECIPITATION. INCREASING FORECAST
UNCERTAINTY HERE IS THE LONG WAVE PATTERN ALSO BECOMES MORE OF A
SPLIT FLOW REGIME...WHICH OFFERS LOW PREDICTABILITY  GIVEN THE
INCREASED FORECAST UNCERTAINTY WILL LEAN/FOLLOW ENSEMBLE GUID
/16-12Z ECENS AND 17-00Z GEFS/ MORE THAN THE DETERMINISTIC
MODELS FROM TUE ONWARD.

SAT NIGHT/SUN BEGINS WITH MID LEVEL CLOSED LOW OVER ATLANTIC CANADA
AND A CORRESPONDING MARITIME HIGH JUST EAST OF NEW ENGLAND. THIS
WILL PROVIDE DRY AND SEASONABLE COOL CONDITIONS SAT NIGHT INTO SUN.
SUN WILL BE COOLER THAN SAT. THEN BY LATE SUN INTO MON THE ATLANTIC
CANADA MID LEVEL LOW MOVES SEAWARD ALLOWING A WARM FRONT SOUTH AND
WEST OF NEW ENGLAND TO APPROACH THE AREA. THIS MAY RESULT IN SOME
WARM ADVECTION PRECIP ACROSS THE REGION FROM LATE SUN /ESP SUN
NIGHT/ INTO MON. A FEW HEAVIER SHOWERS ARE POSSIBLE DURING THIS TIME
AS THE 00Z GEFS INDICATES PWATS OF +2 STD MAY ADVECT INTO SOUTHERN
NEW ENGLAND.

BY TUE AND/OR WED SOUTHERN NEW ENGLAND SHOULD BE IN THE WARM SECTOR
SO A PERIOD OF WARMER MORE HUMID WEATHER IS LIKELY. THEN COMES THE
MORE DIFFICULT PART OF THE FORECAST...HOW FAR SOUTHEAST WILL A
FRONTAL BOUNDARY PROGRESS AS THE LONG WAVE TROUGH OVER SOUTHEAST
CANADA RELOADS WITH YET ANOTHER CLOSED LOW PIVOTING INTO QUEBEC. THE
16/12Z ECENS AND 17/00Z GEFS SUGGEST THE FRONTAL BOUNDARY WILL
REMAIN OVER OR JUST NORTHWEST OF SOUTHERN NEW ENGLAND MUCH OF NEXT
WEEK. THIS SHOULD YIELD WARM AND SOMEWHAT HUMID WEATHER ALONG WITH A
RISK OF MAINLY DIURNAL SHOWERS FROM TUE AND BEYOND.

SO WHILE THE FORECAST FOR NEXT WEEK CONTAINS CHANCE POPS JUST ABOUT
EVERY DAY...NOT EXPECTING A WASHOUT WITH MANY HOURS OF DRY WEATHER
ANTICIPATED ESPECIALLY DURING THE OVERNIGHTS AND INTO THE MORNING
HOURS. AS FOR TEMPS...WARMER THAN NORMAL FROM TUE ONWARD BUT NOT
EXPECTING ANY RECORD HEAT.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
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.

HIGH CONFIDENCE OF VFR CONDITIONS THROUGH SAT NIGHT. N/NW WINDS
WILL DIMINISH THROUGH THE AFTERNOON WITH LOCAL MID/LATE AFTERNOON
SEABREEZES STILL POSSIBLE.

KBOS TERMINAL...SEABREEZE STILL POSSIBLE BY 21Z AS LOW LEVEL
WINDS DIMINISH...BUT CONFIDENCE IS A BIT LOWER. SEABREEZE MORE
LIKELY SATURDAY.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF.

OUTLOOK...SUNDAY THROUGH TUESDAY...

SUN...VFR LIKELY ALONG WITH DRY WEATHER AND LIGHT WINDS. HIGH
CONFIDENCE.

SUN NIGHT THROUGH TUE....MVFR-IFR IN PERIODS OF LIGHT RAIN POSSIBLY
IMPROVING TO VFR TUE. MODERATE CONFIDENCE.

&&

.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 TUESDAY...

SAT NIGHT AND SUN...HIGH PRES OVER GULF OF ME PROVIDES DRY WEATHER
WITH LIGHT WINDS AND GOOD VSBY. HIGH CONFIDENCE.

SUN NIGHT AND MON...HIGH PRES MOVES OFFSHORE WITH SSW WINDS
INCREASING. PERIODS OF LIGHT RAIN AND FOG POSSIBLE. MODERATE
CONFIDENCE.

TUE...SOME IMPROVEMENT POSSIBLE AS WARM FRONT LIFTS NORTH OF THE
REGION. MODERATE CONFIDENCE.

&&

.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...40 TO 50 PERCENT WITH CONTINUED LIGHT
WINDS.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EDT THIS
     AFTERNOON FOR ANZ254-255.

&&

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



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