Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 230325
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1025 PM EST SAT NOV 22 2014

.SYNOPSIS...
A SIGNIFICANT WARM UP IS ON TAP SUNDAY AND ESPECIALLY MONDAY...BUT
WITH A PERIOD OF RAIN SUNDAY NIGHT INTO MONDAY MORNING. QUIET AND
MILD TUESDAY. A COASTAL STORM ANTICIPATED WEDNESDAY INTO THURSDAY
MORNING. GRADUALLY TURNING COLDER INTO THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
1015 PM UPDATE...
NOSE OF 50 KT LOW LEVEL JET ACTING ON DEEPENING MOISTURE RESULTING
IN A FEW SHOWERS MOVING INTO WESTERN NEW ENG. COVERAGE OF PRECIP
IS SOMEWHAT LIMITED DUE TO VERY DRY AIR IN THE LOW LEVELS. MAIN
FOCUS FOR PRECIP OVERNIGHT WILL BE ALONG AND N OF THE PIKE WHERE
MOISTURE IN THE LOW LEVELS IS GREATER. MOISTURE IN THE LOW LEVELS
DECREASES FURTHER S FROM THE PIKE AND MOSTLY DRY CONDITIONS
EXPECTED THROUGH CT/RI AND SE MA. TEMPS IN WESTERN NEW ENG WELL
ABOVE FREEZING IN THE MID 30S TO LOWER 40S AS WESTERLY LOW LEVEL
JET INDUCING S FLOW UP THE CT VALLEY AND SW IN THE BERKSHIRES.
STILL CANT RULE OUT AN ISOLATED POCKET OF SOME LIGHT FREEZING RAIN
INTERIOR HIGH TERRAIN BUT THE THREAT IS DIMINISHING. GUSTY SW
WINDS TO 30-40 MPH ALONG THE COAST WILL BEGIN TO DIMINISH AFTER
MIDNIGHT. THE GUSTY SW WINDS HAVE PUSHED TEMPS TO 45-50 ALONG THE
S COAST AND EXPECT TEMPS TO HOLD IN THE 40S IN THE COASTAL
PLAIN...WITH MID 30S OVER THE INTERIOR HIGH TERRAIN.

UPDATED TEMPS/POPS TO REFLECT FORECAST TRENDS.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
***BRIEF PERIOD OF HEAVY RAIN VERY LATE SUN NIGHT/MON MORNING
  IMPACTING THE AM RUSH HOUR***

SUNDAY...

THE SHORTWAVE SHOULD EXIT THE REGION AND RESULT IN MID LEVEL DRYING.
THIS WILL RESULT IN AT LEAST PARTLY SUNNY SKIES AND MUCH MILDER
TEMPS. 850 MB TEMPS AROUND +5C SHOULD ALLOW HIGH TEMPS TO RECOVER
INTO THE LOWER TO MIDDLE 50S AND LEANED TOWARD THE WARMER GUIDANCE.
GIVEN MID LEVEL TEMPS ARE PRETTY MILD...WOULD NOT BE SHOCKED IF THE
NEXT SHIFT NEEDS TO INCREASE HIGHS A FEW MORE DEGREES. GUIDANCE
SEEMS A BIT COOL CONSIDERING THOSE FACTORS.

SUNDAY NIGHT AND MONDAY...

DRY WEATHER EXPECTED THROUGH SUNDAY EVENING. STRONG LOW PRESSURE
WILL THEN BE PASSING WELL TO OUR WEST ACROSS THE GREAT LAKES VERY
LATE SUN NIGHT INTO MON MORNING. THE WILL CAUSE A STRONG LOW LEVEL
JET TO DEVELOP ALONG WITH PLENTY OF MOISTURE. GEFS IS SHOWING THAT
PWATS INCREASE TO AT LEAST 3 STANDARD DEVIATIONS ABOVE NORMAL.
EXPECT RAIN TO DEVELOP AFTER MIDNIGHT AND CONTINUE INTO MONDAY
MORNING. WITH STRONG FORCING AND HIGH PWATS IN PLACE...BRIEF HEAVY
RAIN IS EXPECTED BUT FORTUNATELY SYSTEM IS FAIRLY PROGRESSIVE.
EXPECT MOST RAINFALL AMOUNTS TO BE IN THE ONE HALF TO 1 INCH
TERRITORY ALTHOUGH LOCALLY HIGHER AMOUNTS ARE POSSIBLE. NOT TOO
CONCERNED ABOUT FLOODING...BUT SOME MINOR POOR DRAINAGE ISSUES ARE
POSSIBLE AND THIS WILL COINCIDE WITH THE MONDAY MORNING RUSH HOUR.
THERE ALSO IS A LOW RISK FOR AN ISOLATED THUNDERSTORM OR TWO
ACROSS THE SOUTHEAST NEW ENGLAND COAST.

THE OTHER CONCERN IS POTENTIAL FOR WINDS ON MONDAY. WE COULD SEE
SOUTH SOUTHEAST WIND GUSTS OF 30 TO 40 MPH DEVELOP ACROSS THE
SOUTHEAST NEW ENGLAND COAST TOWARDS 12Z MONDAY...BUT INVERSION
SHOULD KEEP THE STRONGEST WINDS JUST ABOVE OUR HEADS. THE ONE FLY
IN THE OINTMENT IS IF WE CAN GENERATE A LITTLE FINE LINE THAT
COULD ALLOW FOR A FEW LOCATIONS TO BRIEFLY TOUCH WIND ADVISORY
CRITERIA ACROSS THE SOUTHEAST NEW ENGLAND COAST MONDAY MORNING.

BULK OF THE RAIN IS OVER BY MON AFTERNOON...BUT A FEW LEFT OVER SPOT
SHOWERS ARE POSSIBLE. GUIDANCE APPEARS TOO COOL FOR HIGHS GIVEN
850 MB TEMPS REMAINING AROUND +10C. SHOULD SEE HIGHS CLIMB WELL
INTO THE 60S IN MANY LOCATIONS. NOT OUT OF THE QUESTION THAT SOME
LOCALES APPROACH 70 IF WE CAN MUSTER A FEW PEEKS OF SUN. GUSTY
SOUTHWEST WINDS POSSIBLE...ESPECIALLY IF WE CAN MIX OUT A BIT.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
*/ HIGHLIGHTS...

- DRY AND MILD AROUND TUESDAY
- STORM SYSTEM ANTICIPATED WEDNESDAY INTO THURSDAY MORNING
- GRADUALLY TURNING COLDER INTO THE FOLLOWING WEEKEND

*/ OVERVIEW AND MODEL CONSENSUS...

ECHO SIMILAR SENTIMENTS PER WPC: MEANINGFUL SHORT-WAVE DIFFERENCES
LEND TO LOW CONFIDENCE...SIGNIFICANT SPREAD DOWNSTREAM OF PACIFIC-
ORIGIN ENERGY LEND TO FORECAST UNCERTAINTY. WITH UPSTREAM ISSUES IN
HANDLING PACIFIC ENERGY...IT IS DIFFICULT TO RESOLVE DETAILS OFF THE
E-COAST AND WE MAY NOT KNOW THE TRUE IMPACTS / OUTCOMES UNTIL WE GET
WITHIN 2-3 DAYS OF THE TIMEFRAME.

HAVE ONLY A MODEST CONFIDENCE IN THE FORECAST...BELOW-AVERAGE
PREDICTABILITY. STILL BELIEVE THAT THE STORM ITSELF WILL REMAIN ON
THE W-SIDE OF THE ENVELOPE OF MODEL SOLUTIONS /AGREED UPON BY WPC/
IN THE VICINITY OF THE 40N / 70W BENCHMARK SO DO NOT PREFER A DRY
OUTCOME.

CONSIDER OVER THE PAST COUPLE OF MONTHS ANOMALOUSLY WARM CONDITIONS
HAVE PREVAILED S OF NOVA SCOTIA. LATELY THE TREND HAS BEEN COLD AIR
SURGING S THROUGH THE C-CONUS TO THE GULF WITH NEW ENGLAND AVERAGING
WITHIN THE E-PERIPHERY OF THE BROADER TROUGH. FEEL TREND CONTINUES
WITH THIS FORECAST. LACK OF ARCTIC AIR INTO THE REGION...BELIEVE
RIDGING OVER THE W-ATLANTIC WILL KEEP THE BULK OF SYNOPTICS ACROSS
OUR REGION.

SO FROM MONDAY NIGHT INTO TUESDAY NIGHT...

DRY FORECAST. BLUSTERY W/SW FLOW ACROSS THE WATERS / SHORES WITH THE
WARMER OCEAN. OVER THE INTERIOR DURING THE DAY TUESDAY AS MOSTLY
CLEAR TO PARTLY CLOUDY CONDITIONS ALLOW FOR BOUNDARY-LAYER MIXING UP
TO H9. GUSTS OF AROUND 30 TO 35 MPH... STRONGEST OVER THE SHORES AND
ADJACENT WATERS. WILL REMAIN MILD BENEATH THE SW-FLOW. HIGHS TO NEAR-
60S AS A WARMER AIRMASS LINGERS ALOFT.

NOW AS TO THE STORM...

SYNOPTICALLY...SERIES OF PACIFIC WAVES INVOKE / MAINTAIN A H5 OPEN-
WAVE TROUGH STRETCHING S INTO THE GULF. NO UPSTREAM BLOCKING WITH
TELECONNECTIONS OF +AO/+NAO INDICATING A PROGRESSIVE FLOW OF MID-
LEVEL IMPULSES. INTERACTING WITH THE OFFSHORE SW-NE FRONTAL BOUNDARY-
BAROCLINIC ZONE AS IT BECOMES NEGATIVELY-TILTED RESULTS IN DEEPENING
SFC-H85 LOW PRESSURE UP ALONG THE W-ATLANTIC PASSING WITHIN VICINITY
OF THE 40N / 70W BENCH-MARK AROUND MIDNIGHT THURSDAY UP AGAINST AN
INTERIOR REGION LACKING OF CANADIAN HIGH PRESSURE / ARCTIC AIR.

INITIALLY...BAROCLINIC LEAF / OVER-RUNNING PATTERN OF BROADSCALE
ASCENT YIELDS TOP-DOWN MOISTENING OF MID- TO LOW-LEVELS DYNAMICALLY
COOLING TOWARDS EVENING SETTING UP THE ENVIRONMENT AHEAD OF THE MAIN
STORM. UNDERCUTTING MARGINALLY COLD AIR AIDED BY SURFACE N/NE-FLOW
WITH W/NW AGEOSTROPHIC FLOW OF INTERIOR ORIGIN LOOK TO KEEP THE N/W
INTERIOR AROUND THE FREEZING MARK...MILD ACROSS THE COASTAL PLAIN.
THERMAL FIELDS DIFFICULT TO DIAGNOSE WITH FORECAST UNCERTAINTY.
KEY IS THE TRACK AND LOCATION OF H85 LOW / H925 < -2C. WHILE
LIKELY TO SEE LOWER DEWPOINTS AND DRIER AIR N/W...ANOTHER KEY TO
THE FORECAST TO THE TOP-DOWN MOISTENING IS WETBULBING AT THE
SURFACE.

AROUND MIDNIGHT THURSDAY INTO THURSDAY MORNING...SURFACE LOW LOOKS
TO TRACK WITHIN THE VICINITY OF 40N / 70W BENCHMARK. UNCERTAIN AS TO
DEPTH / STRENGTH / EXACT TRACK. EXPECT STRONG DEEP-LAYER ASCENT BUT
FEEL BEST MOISTURE WILL BE E OF THE LOW WITHIN THE ANTI-CYCLONIC
BRANCH OF THE WARM-CONVEYER-BELT /WCB/. THOUGH FORCING THROUGH A
MOIST DENDRITIC GROWTH ZONE NW OF THE H85 LOW BENEATH THE RRQ OF THE
UPPER-LEVEL-JET...HEAVIEST PRECIPITATION LOOKS TO REMAIN E/NE WITH
THE LACK OF A STRONG H7 CLOSED LOW AND LITTLE EVIDENCE OF BANDING
NOR -EPV /CYCLONIC BRANCH OF THE WCB LACKING/. COLD AIR CONTINUES TO
UNDERCUT BUT MARGINAL /AROUND UPPER-20S TO LOW-30S/. NO NEIGHBORING
ARCTIC AIRMASS IN PLACE. WETBULBING LIKELY CONTINUES. SNOWS N/W OF
THE H85 LOW WITH RAIN ELSEWHERE. REMAIN UNCERTAIN AS TO AMOUNTS /
HEADLINES AS MODEL RUNS /WHILE PERSISTENT/ CONTINUE TO WOBBLE WITH
THE LOW AND POTENTIAL OUTCOMES. ACTIVITY CONCLUDING THANKSGIVING DAY
MORNING REARWARD OF WHICH SOME STRONG SW-FLOW IS POSSIBLE. SEE THE
ADDITIONAL DETAILS BELOW:

SNOWS / HEAVY RAIN...HIGHEST CONFIDENCE ACROSS THE N/W INTERIOR FOR
SNOW WITH HEAVY RAIN OVER SE MA...BUT STILL A LOT OF UNCERTAINTY AS
HIGHLIGHTED IN THE DISCUSSION ABOVE. NOT EVEN DOES CIPS ANALOGS
PROVIDE SIGNIFICANT CONFIDENCE...AND WITH THE WOBBLING OF MODEL
SOLUTIONS CONCERNING THE TRACK / STRENGTH OF THE LOW...IT IS ANYONES
GUESS AS TO SNOWFALL AMOUNTS.

WINDS...SOME CONCERN DEPENDING THE DEPTH OF THE LOW. NE-FLOW AHEAD
OF THE LOW WILL BE STRONG...BUT SOME CONCERN AFTER THE LOW PASSES
WITH SW-FLOW IMPACTING THE S-COAST. LIKELY TO BE AN ACCOMPANYING
STRONG LOW-LEVEL-JET. WITH THE 22.12Z GFS...CIPS ANALOGS HAVE A
ROBUST CONFIDENCE OVER SE NEW ENGLAND /MAINLY THE CAPE AND
ISLANDS/ FOR GUSTS EXCEEDING 35 MPH...POSSIBLY 40 MPH. BEARS
MONITORING.

COASTAL FLOODING...INCREASING WINDS OUT OF THE NE ALONG E MA INTO
CAPE COD BAY. A BRIEF SURGE ANTICIPATED AS WINDS INCREASE AHEAD OF
THE LOW-CENTER PASSAGE AROUND MIDNIGHT THURSDAY. THOUGH HIGH TIDES
SHORTLY AFTER MIDNIGHT ARE FORECAST TO BE ASTRONOMICALLY LOW /10 FT
FOR BOSTON/. WITH THE SHORT RESIDENCY TIME...AM NOT ANTICIPATING AT
THIS TIME MUCH IN THE WAY OF IMPACTS BASED ON THE FORECAST MODEL
PREFERENCE.

THANKSGIVING AND BEYOND...

CONTINUED PACIFIC ENERGY ROTATING THROUGH THE BROADER OPEN-WAVE H5
TROUGH WILL TO NEED TO BE MONITORED AS TO WHETHER MID-LEVEL IMPULSES
INVOKE ANOTHER OFFSHORE LOW AROUND FRIDAY. ONCE THE H5 TROUGH PUSHES
THROUGH THE REGION...EXPECT THE RETURN OF BELOW-AVERAGE TEMPERATURES
USHERED BY NW-FLOW.

&&

.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT-TERM /THROUGH MONDAY/...

0Z UPDATE...HIGH CONFIDENCE.

TONIGHT...

LOW-END VFR CIGS AT WORST. MAINLY MID-LEVEL CLOUD DECK. ISO-SCT
-SHRA. ISO -FZRA POSSIBLE ACROSS N/W MA AND S NH. NOT TO BE
WIDESPREAD.

MAIN CONCERN: GUSTY W/SW WINDS 25-30 KTS OVER THE HIGH TERRAIN
AND E-SHORELINE WHILE 30-35 KTS ACROSS THE S/SE SHORELINE. LLWS A
FACTOR WITH W/SW JET 2 KFT AGL AROUND 40-45 KTS...ESPECIALLY OVER
THE INTERIOR WITH DIMINISHED WINDS AND MORE S-FLOW TRAJECTORY.

SUNDAY...HIGH CONFIDENCE. VFR.

SUNDAY NIGHT INTO MONDAY...MODERATE CONFIDENCE.

DETERIORATING CONDITIONS TO MVFR-IFR WITH WIDESPREAD RAIN AND
EMBEDDED +RA BEGINNING AROUND MIDNIGHT MONDAY INTO THE MORNING...
TAPERING BY AFTERNOON. LOW RISK TSRA MONDAY MORN ALONG S-COAST.
S-WINDS BY DAYBREAK GUSTING 30-40 KTS OVER E/SE MA...RI...AND E/SE
CT...PERHAPS STRONGER WITH ANY +RA/TSRA. LLWS WILL BE A CONCERN
WITH S JET 2 KFT AGL AROUND 50 KTS.

WHILE WET WEATHER EXITS INTO THE AFTERNOON AND CONDITIONS IMPROVE
TO VFR...S/SW WINDS REMAIN BRISK WITH 30-40 KT GUSTS OVER SE MA
AND S RI.

KBOS TERMINAL...HIGH CONFIDENCE. -SHRA TOO ISOLATED TO WARRANT A
MENTION. COLLABORATION WITH CWSU...WILL CONTINUE LLWS THREAT INTO
THE EARLY MORNING PERIOD. TDWR / AMDAR SOUNDINGS OBSERVING WINDS
2-3 KFT AGL AROUND 50 KTS.

KBDL TERMINAL...HIGH CONFIDENCE. -SHRA TOO ISOLATED TO WARRANT A
MENTION. S-FLOW PREVAILING...WARMER CONDITIONS...DO NOT BELIEVE
-FZRA WILL BE AN ISSUE FOR THE TERMINAL.

OUTLOOK...MONDAY NIGHT THROUGH THURSDAY.

MONDAY NIGHT THROUGH TUESDAY NIGHT...MODERATE CONFIDENCE.

W/SW-FLOW DIMINISHING THROUGH TUESDAY WITH GUSTS OF AROUND 30 KTS
OVER SE-COASTAL TERMINALS THROUGHOUT MONDAY NIGHT. VFR.

WEDNESDAY INTO THURSDAY MORNING...LOW CONFIDENCE.

STORM WILL BRING SIGNIFICANT IMPACTS TO THE TERMINALS. THREATS
CONSIDERED ARE STRONG WINDS AND THE THREAT OF +RA ALONG THE SHORES
WITH SNOW SOMEWHERE ACROSS THE INTERIOR. EXACT SPECIFICS UNCERTAIN
BUT EXPECTING A MIX OF IFR-VLIFR CONDITIONS. HEIGHT OF THE STORM
WILL BE AROUND MIDNIGHT THURSDAY.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /THROUGH MONDAY/...

7 PM UPDATE...

TONIGHT...HIGH CONFIDENCE.

STRONG W/SW FLOW CONTINUES EXCEEDING GALE FORCE. BOATS ACROSS THE
S-WATERS REPORTING GUSTS UP TO AROUND 40 KTS AT TIMES. GALE FORCE
WARNINGS CONTINUE WITH THE THREAT OF AVERAGE WIND GUSTS AROUND 35
KTS...ONLY SMALL-CRAFTS FOR NARRAGANSETT BAY AND BOSTON HARBOR
WHICH SHALL REMAIN SHELTERED FROM THE WINDS. SEAS BUILDING 6-10
FEET OVER THE S-WATERS.

SUNDAY...HIGH CONFIDENCE.

GUSTY SW WINDS 25-30 KT IN THE MORNING WILL BE DIMINISHING
THROUGH THE AFTERNOON DROPPING BELOW SCA DURING AFTERNOON AS LOW
LEVEL JET WEAKENS. LEFT OVER SWELL WILL KEEPS SEAS ABOVE SMALL
CRAFT ADVISORY THRESHOLDS ACROSS THE SOUTHERN WATERS THROUGH THE
AFTERNOON.

SUNDAY NIGHT AND MONDAY...MODERATE CONFIDENCE.

WIND WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS SUNDAY
EVENING. LOW PRESSURE WILL THEN LIFT TOWARDS THE GREAT LAKES
ALLOWING A STRONG LOW LEVEL JET TO DEVELOP VERY LATE SUN NIGHT
INTO MON. THERE WILL BE AN INVERSION AND ITS ALWAYS UNCERTAIN AS
TO HOW MUCH OF THIS WIND WILL BE ABLE TO MIX DOWN. AT THE VERY
LEAST WILL HAVE STRONG SCA TO PERHAPS GALE FORCE SOUTHERLY WIND
GUSTS VERY LATE SUN NIGHT INTO MON. SEAS WILL LIKELY BUILD TO
BETWEEN 10 AND 15 FEET ACROSS THE SOUTHERN WATERS WITH VERY LONG
FETCH.

OUTLOOK...MONDAY NIGHT THROUGH THURSDAY.

MONDAY NIGHT THROUGH TUESDAY...MODERATE CONFIDENCE.

WINDS TURNING W/SW REMAINING BLUSTERY WITH GUSTS AROUND 30 KTS FOR
MONDAY NIGHT...RELAXING THROUGH THE DAY TUESDAY THOUGH GUSTS UP TO
30 KTS EXPECTED. WAVES AROUND 10 FEET ON THE OUTER WATERS EXPECTED
INITIALLY INTO TUESDAY MORNING...DIMINISHING THEREAFTER.

WEDNESDAY INTO THURSDAY...LOW CONFIDENCE.

STORM WILL BRING SIGNIFICANT IMPACTS TO THE WATERS. THREATS
CONSIDERED ARE GALE-FORCE WINDS AND THE THREAT OF HEAVY RAIN ACROSS
THE WATERS. EXACT SPECIFICS UNCERTAIN BUT EXPECTING SEAS TO ENHANCE
AROUND THE STORM CENTER WHICH LOOKS TO PASS IN VICINITY OF THE 40N /
70W BENCHMARK AROUND MIDNIGHT THURSDAY...VISIBILITIES REDUCED WITH
HEAVY RAIN.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WARNING UNTIL 4 AM EST SUNDAY FOR ANZ231-232.
     GALE WARNING UNTIL 3 AM EST SUNDAY FOR ANZ233>235-237-256.
     SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ230-236-251.
     GALE WARNING UNTIL 6 AM EST SUNDAY FOR ANZ250-254-255.

&&

$$
SYNOPSIS...FRANK/SIPPRELL
NEAR TERM...KJC/FRANK
SHORT TERM...FRANK
LONG TERM...SIPPRELL
AVIATION...FRANK/SIPPRELL
MARINE...FRANK/SIPPRELL



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