Area Forecast Discussion
Issued by NWS Boston, MA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KBOX 281136
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
736 AM EDT SUN SEP 28 2014

.SYNOPSIS...
ANOTHER DAY OF SUMMERLIKE WARMTH IS AHEAD TODAY AS HIGH PRESSURE
HEADS OFF THE COAST. A FRONT WILL DROP SOUTH ACROSS THE REGION
LATE MONDAY...BRINGING A FEW SHOWERS. A COOLER NORTHEAST WIND WILL
CONTINUE THROUGH THE REMAINDER OF THE WEEK. THE PERSISTENT ONSHORE
FLOW MAY BRING A FEW ISOLATED SHOWERS INTO AT LEAST MID WEEK ALONG
WITH NIGHTTIME PATCHY DRIZZLE. A COASTAL LOW LOOKS TO PASS WELL
SOUTH OF THE REGION LATE THIS WEEK...BUT MAY CLIP SOUTH COASTAL
AREAS WITH A FEW SHOWERS.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...
PATCHY DENSE FOG CONTINUES ACROSS MOST OF THE CT VALLEY INTO THE
VALLEYS OF THE BERKSHIRES AT 11Z...PLUS A FEW MORE LOCALES ACROSS
SE AND INTERIOR E MA. EXPECT THE FOG TO DISSIPATE OVER THE NEXT
COUPLE OF HOURS AS THE SUN RISES AND MAINLY CLEAR SKIES ABOVE.
NOTING A BAND OF HIGH CLOUDS ON LATEST IR SATELLITE LOOP PUSHING
NE OUT OF CENTRAL NY/E PA.

TEMPS WERE LOWER THAN FORECAST OVER THE LAST SEVERAL HOURS...AND
DEWPTS NEEDED A LITTLE ADJUSTING ON THIS UPDATE. UPDATED THESE
ALONG WITH SKY GRIDS TO TAKE INTO ACCOUNT THE LOW CLOUDS
ASSOCIATED WITH THE PATCHY DENSE FOG...AND INCORPORATED INTO NEAR
TERM TRENDS. REMAINING GRIDS WERE IN GOOD SHAPE.

PREVIOUS DISCUSSION...
AFTER FOG BURNS OFF...ANOTHER DAY WITH PLENTY OF SUNSHINE IS
AHEAD. MORE OF S-SW FLOW IN PLACE TODAY WITH HIGH PRESSURE OFF
COAST...BUT GRADIENT LOOKS TO BE WEAK ENOUGH TO ALLOW FOR FEW
HOURS OF SEA BREEZES ALONG BOTH COASTS. HIGHS WILL RUN A FEW
DEGREES WARMER THAN YESTERDAY GIVEN TEMPERATURES ALOFT...WHICH
SHOULD REACH MID 80S AWAY FROM COAST. RECORD HIGHS AT
PROVIDENCE...WINDSOR LOCKS AND PERHAPS WORCESTER WILL BE
CHALLENGED TODAY /SEE CLIMATE SECTION BELOW/.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
SHOULD BE A MILDER NIGHT TONIGHT WITH BROAD S/SW FLOW IN PLACE...
OTHERWISE CLEAR SKIES WITH A RETURN OF PATCHY DENSE FOG IN LOW
LYING AREAS. LOWS WILL DROP BACK INTO 50S AND LOWER 60S.

TIMING OF COLD FRONT DROPPING S THROUGH REGION MON IS HANDLED WELL
BY 00Z MODELS. IT SHOULD REACH MA/NH BORDER 12Z-15Z...PUSH
THROUGH BOSTON AND MASS PIKE CORRIDOR BY 18Z THEN MUCH OF CT...RI
AND SE MA BY 21Z OR SO. INCREASING NE FLOW BEHIND FRONT WILL
AFFECT MUCH OF E MA MON AFTERNOON...SO HIGHS FROM BOSTON TO NE MA
WILL OCCUR LATE IN MORNING...BEFORE READINGS DROP DURING AFTERNOON.
IN FACT NAM 2M TEMPERATURES FALL INTO UPPER 50S BY EVENING AROUND
CAPE ANN. FARTHER INLAND...IT IS USUALLY DIFFICULT FOR COOLER AIR
TO PENETRATE MUCH PAST WORCESTER HILLS SO WARMEST READINGS WILL BE
FOUND IN WESTERN NEW ENGLAND.

NOT EXPECTING MUCH IN WAY OF SHOWERS AS FRONT PUSHES THROUGH...
ESPECIALLY GIVEN LACK OF SIGNIFICANT LIFT AND DEEP MOISTURE AS
SEEN ON FORECAST CROSS SECTIONS. INCLUDED MENTION OF ISOLATED
SHOWERS BUT ANY ACTIVITY SHOULD BE BRIEF AND NOT PRODUCE MUCH IN
WAY OF RAINFALL.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
HEADLINES...

* A FEW SHOWERS POSSIBLE MONDAY NIGHT INTO TUESDAY
* UNCERTAIN FORECAST AFTER TUESDAY
* LOW PRESSURE MAY DEVELOP MIDWEEK OFF SOUTHEAST COAST WHICH SHOULD
  TRACK S OF THE REGION

OVERVIEW...

MEDIUM RANGE MODELS CONTINUE TO STRUGGLE WITH EVOLVING AMPLIFIED
UPPER LEVEL PATTERN ACROSS THE LOWER 48...WITH H5 TROUGH AND CUTOFF
LOW ACROSS THE WESTERN STATES. WEAK TROUGHING DEVELOPS ACROSS THE
OHIO VALLEY...WHICH ALLOWS A BROAD SURFACE REFLECTION TO BEING
FORMING OVER THE SE STATES THAT MOVES OFF THE COAST.

MODELS HAVING TROUBLE RESOLVING THE EVOLUTION OF THIS PATTERN
AFTER TUESDAY...AS THE WESTERN TROUGH TRIES TO OPEN UP AND BECOMES
NEGATIVELY TILTED...SLOWLY SHIFT E OVER TIME. MEANWHILE...THE
WEAKER EASTERN TROUGH TRIES TO SPIN UP A COASTAL LOW SOMEWHERE OFF
THE CAROLINAS BY MID WEEK. NOTING SOME GENERAL AGREEMENT BETWEEN
THE GFS AND GGEM...THOUGH THE 00Z EC APPEARS A BIT BETTER. ONE
THING THAT APPEARS TO BE WELL AGREED UPON...LARGE SURFACE HIGH
THAT BUILDS SE OUT OF CENTRAL CANADA ACROSS QUEBEC DURING THE
WEDNESDAY-FRIDAY TIMEFRAME...WITH RIDGING BUILDING DOWN THE COAST.

THE BIG PROBLEM WILL BE THE PERSISTENT NE WIND FLOW THAT WILL BE
IN PLACE BETWEEN THE HIGH TO THE N AND GENERAL LOW PRES/TROUGHING
TO THE S. THIS WILL KEEP COOL TEMPS IN PLACE ALONG WITH PERIODS OF
CLOUDS WITH A FEW ISOLD SHOWERS...ALONG WITH SOME POSSIBLE PATCHY
FOG AND DRIZZLE DURING THE NIGHTTIME HOURS AT LEAST AROUND MID
WEEK.

BY LATE THIS WEEK...THE WESTERN TROUGH LOOKS TO DIG AGAIN AS IT
WORKS EASTWARD IN RESPONSE TO SLOW PROGRESSION OF POSSIBLE H5
CUTOFF LOW SOMEWHERE OFF THE MID ATLC OR NEW ENGLAND COAST.
SO...WHILE ONSHORE WINDS CONTINUE...MAY SEE MORE SHOWERS TRY TO
MOVE IN BY EARLY NEXT WEEKEND. TIMING IS STILL VERY MUCH IN
QUESTION THOUGH DUE TO WIDE VARIANCE IN MODEL SOLUTIONS.

DETAILS...

MONDAY NIGHT...COLD FRONT SETTLES S OF NEW ENGLAND WITH
INCREASING NE WIND FLOW ESPECIALLY ALONG THE E COAST OF MASS. MAY
SEE GUSTS UP TO AROUND 25 KT FOR A TIME ALONG THE E COAST
OVERNIGHT MAINLY FROM BOSTON UP TO CAPE ANN. EXPECT THE WINDS TO
DIMINISH DURING THE PRE DAWN HOURS. MAY SEE SOME SHOWERS AS A
PIECE OF AN H5 SHORT WAVE MOVES ACROSS. THE ONSHORE FLOW MAY ALSO
BRING SOME PATCHY DRIZZLE MAINLY AFTER MIDNIGHT. IT WILL BE MILD
WITH LOWS IN THE 50S.

TUESDAY THROUGH THURSDAY...AS THE COASTAL LOW TRIES TO TAKE SHAPE
OFF THE SE U.S. COAST...HIGH PRES REMAINS OVER EASTERN CANADA.
THIS WILL KEEP A PERSISTENT NE WIND IN PLACE...BRINGING COOL TEMPS
AND PERSISTENT CLOUDS AT LEAST TO MID WEEK. DAYTIME HIGHS WILL RUN
AROUND 5 DEGREES BELOW SEASONAL NORMALS TUE AND WED...THOUGH
EXTREME SOUTHERN AREAS MAY BE CLOSER TO NORMAL. CONDITIONS MAY BE
A BIT BETTER DURING THURSDAY AS ANOTHER WEAK RIDGE TRIES TO BUILD
S OUT OF QUEBEC...THOUGH NE WINDS CONTINUE. TEMPS WILL BE CLOSER
TO SEASONAL NORMS. HOWEVER...WILL SEE SOME POSSIBLE SHOWERS...WITH
THE BEST CHANCE ACROSS CAPE COD AND THE ISLANDS DURING THU AS THE
SE U.S. LOW MAY TRY TO PUSH OFFSHORE WELL S AND E OF NANTUCKET.

FRIDAY-SATURDAY...PERSISTENT NE WINDS CONTINUE...WHICH WILL KEEP
SOME CLOUDS AND EVEN AN ISOLD SHOWER OR TWO. ANOTHER FRONT TRIES
TO SLOWLY APPROACH FROM THE W LATE FRI OR SAT...BUT TIMING IS
STILL VERY MUCH IN QUESTION.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM...HIGH CONFIDENCE THROUGH MON.

LOCALIZED IFR/LIFR CIGS/VSBYS IN PATCHY DENSE FOG WILL DISSIPATE
BY 14Z. OTHERWISE...EXPECT VFR TODAY WITH LIGHT S-SW FLOW. SEA
BREEZES SHOULD DEVELOP AROUND MIDDAY ALONG BOTH COASTS...THOUGH IT
WILL BE WEAK ALONG E MA COAST AND PROBABLY WILL NOT GET VERY FAR
INLAND.

PATCHY FOG EXPECTED ONCE AGAIN TONIGHT BUT ANY IFR/LIFR WILL BE
LOCALIZED...LESS SO THAN THIS MORNING.

COLD FRONT DROPS S ACROSS REGION MON WITH WIND SHIFT TO N/NE.
TIMING IS 12Z-15Z ALONG MA/NH BORDER...AROUND 18Z BAF-ORH-BOS...
BY 21Z BDL-PVD-PYM AND CLOSER TO 00Z TUE ALONG S COAST...CAPE COD
AND ISLANDS. VFR CIGS 040-050 AHEAD OF FRONT BUT EXPECT CIGS TO
LOWER TO MVFR BEHIND IT...MAINLY LATE IN DAY ACROSS S NH AND N MA.
MAY ALSO BE ISOLD SHOWER.

KBOS TERMINAL...HIGH CONFIDENCE IN TAF. SEA BREEZE ONSET SHOULD BE
A BIT LATER THAN USUAL...MORE LIKE 16Z-18Z...AND IT MAY BE WEAK
ENOUGH THAT IT MAY REMAIN OVER BOS HARBOR OR ON E END OF AIRPORT.

KBDL TERMINAL...HIGH CONFIDENCE IN TAF.

OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...

MONDAY NIGHT-TUESDAY...MODERATE CONFIDENCE. VFR. LEFTOVER SCT
SHOWERS POSSIBLE BEHIND COLD FRONT WITH LOCAL MVFR CIGS/VSBYS
POSSIBLE. PATCHY LATE NIGHT/EARLY MORNING FOG AND DRIZZLE ALSO
POSSIBLE. NE WINDS MAY PICK UP ALONG THE IMMEDIATE E COAST
OVERNIGHT...GUSTS TO 20-25 KT POSSIBLE FROM KBOS TO KBVY MON NIGHT
INTO EARLY TUE.

TUESDAY NIGHT THROUGH THURSDAY...MODERATE CONFIDENCE. MAINLY VFR...
THOUGH COULD SEE PATCHY MVFR CIGS ESPECIALLY ALONG THE COAST WITH
PERSISTENT ONSHORE WINDS. WIDELY SCT SHOWERS MAY LINGER ACROSS
REGION WITH THE MOIST AIRMASS IN PLACE. PATCHY DRIZZLE ALSO POSSIBLE
TUE NIGHT.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM...HIGH CONFIDENCE THROUGH MON.

HIGH PRESSURE MOVES OFFSHORE TODAY WITH LIGHT S/SW FLOW AND FLAT
SEAS THROUGH TONIGHT. WEAK SEA BREEZES DEVELOP AROUND MIDDAY.

COLD FRONT PUSHES S ACROSS WATERS MON...FIRST NEAR MERRIMACK RIVER
IN MORNING AND PROBABLY NOT REACHING S COAST UNTIL LATE AFTERNOON.
SW WINDS GIVE WAY TO WIND SHIFT TO N/NE BEHIND FRONT...AND MAY
REACH 25 KT LATE IN DAY FROM BOSTON TO MERRIMACK RIVER AS SEAS
BUILD TO 3 TO 5 FT. SCA MAY BE NEEDED FOR THESE AREAS.

OUTLOOK...MONDAY NIGHT THROUGH THURSDAY...

MONDAY NIGHT...MODERATE CONFIDENCE. COLD FRONT MOVES S INTO THE
REGION. NE WINDS WILL INCREASE ACROSS THE EASTERN WATERS...GUSTING
UP TO 25-30 KT /HIGHEST WELL OFFSHORE/. SEAS WILL ALSO BUILD OVER
THE OPEN WATERS...UP TO 5-6 FT E OF CAPE ANN TO E OF BOSTON HARBOR.
SMALL CRAFT WILL LIKELY BE CONTINUED.

TUESDAY THROUGH THURSDAY...MODERATE CONFIDENCE. PERSISTENT NE WINDS
REMAIN IN PLACE. LONG NE GROUND SWELLS WILL BUILD UP DURING THE WEEK
ESPECIALLY ACROSS THE EASTERN WATERS. THE SWELLS MAY BUILD UP TO 7-
12 FT BY THURSDAY. VSBY RESTRICTIONS ALSO POSSIBLE ON THE SOUTHERN
OUTER WATERS IN SCT SHOWERS AND PATCHY FOG.

&&

.CLIMATE...
RECORD HIGHS FOR TODAY 9/28

BOSTON.......... 90 IN 1881 AND PREVIOUS YEARS
PROVIDENCE...... 84 IN 1943
WORCESTER....... 84 IN 1916
WINDSOR LOCKS... 83 IN 1959

&&

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

&&

$$
SYNOPSIS...EVT/JWD
NEAR TERM...EVT/JWD
SHORT TERM...JWD
LONG TERM...EVT
AVIATION...EVT/JWD
MARINE...EVT/JWD
CLIMATE...STAFF



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.