-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBOX 271516
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
1016 AM EST FRI FEB 27 2015

.SYNOPSIS...
HIGH PRESSURE SLOWLY BUILDING IN FROM THE WEST WILL BRING DRY BUT
UNSEASONABLY COLD WEATHER INTO SUNDAY MORNING. A LOW PRESSURE SYSTEM
WILL BRING A PERIOD OF SNOW LATE SUNDAY INTO MONDAY. ANOTHER
STORM IS LIKELY TUESDAY INTO WEDNESDAY...WITH PRECIPITATION TYPES
UNCERTAIN.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
1015 AM UPDATE...

NO MAJOR CHANGES TO PREVIOUS FORECAST. STILL EXPECTING A MAINLY
DRY DAY WITH TEMPS REBOUNDING INTO THE 20S...SO STILL WELL BELOW
NORMAL...BUT AS THE PREVIOUS FORECASTER NOTED THE LACK OF WIND AND
THE ADDITION OF SUN TODAY WILL MAKE IT MORE TOLERABLE THAN SOME
OF THE PREVIOUS COLD DAYS.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
TONIGHT...

LARGE HIGH PRESSURE WILL CONTINUE TO BUILD IN FROM THE WEST.  SKIES
WILL BECOME MOSTLY CLEAR ALONG WITH LIGHT WIND.  THE RESULT WILL BE
AN EXCELLENT NIGHT OF RADIATIONAL COOLING OVER THE DEEP SNOW PACK.
LOW TEMPS WILL BOTTOM OUT BETWEEN 5 AND 15 BELOW ZERO ACROSS THE
NORMALLY COLDEST OUTLYING LOCATIONS...WHILE OTHER LOCATIONS SEE
LOW TEMPS IN THE SINGLE DIGITS TO AROUND 10 ABOVE.

SATURDAY...

HIGH PRESSURE WILL REMAIN IN CONTROL OF THE REGION.  SUNNY SKIES
WILL ALLOW FOR HIGH TEMPS TO REBOUND INTO THE MIDDLE TO UPPER 20S
SAT AFTERNOON.  WINDS WILL ONCE AGAIN BE RATHER LIGHT...SO IT WILL
FEEL A BIT MORE TOLERABLE BY AFTERNOON WITH THE HELP OF THE LATE
FEBRUARY SUN ANGLE.  NONETHELESS...THESE HIGH TEMPS WILL STILL BE
ABOUT 15 DEGREES BELOW NORMAL.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
*  HIGH PRESSURE SATURDAY NIGHT INTO SUNDAY
*  COLD FRONT BRINGS SNOW SUNDAY NIGHT INTO MONDAY
*  ANOTHER STORM POSSIBLE TUESDAY...PTYPE LESS CERTAIN

OVERVIEW AND MODEL PREFERENCES...
NOTING LITTLE CHANGE IN THE OVERALL PATTERN THROUGH THE LONG TERM
WITH NAO/AO REMAINING PRIMARILY NEGATIVE. THE BIGGEST CHANCE IS IN
THE PNA WHICH LOOKS TO TREND NEGATIVE UNDER A NEGATIVE EPO.
THEREFORE..THIS IS SLIGHTLY DIFFERENT THAN THE OVERALL PATTERN
ACROSS NOAM DURING THE SNOW BLITZ PERIOD. AT ODDS PRIMARILY IS A
SPLIT FLOW REGIME AND THEIR MERGER /OR LACK THEREOF/ ACROSS THE
ERN HALF OF THE CONUS. THE FIRST WAVE TO WATCH ARRIVES VIA THE NRN
STREAM SUN NIGHT INTO MON...MANIFESTING AS LOW PRES THROUGH SRN
CANADA AND A COLD FRONTAL PASSAGE ACROSS NEW ENGLAND. THE SECOND
MAY BE A RESULT OF PHASING OF THESE TWO STREAMS AS WAVES MOVE
THROUGH...WHICH IS LIKELY WHY MODELS HAVE BEEN STRUGGLING TO
SETTLE ON A SOLUTION FOR THE SFC AND LOW LVL FEATURES.
HOWEVER...GIVEN THIS DOES INVOLVE THE SRN STREAM...WILL LIKELY SEE
MORE MOISTURE AND HIGHER LATENT HEAT RELEASE RESULTING IN A
STRONGER SYSTEM. MODELS ARE TRENDING WARMING IN THE LOW-MID
LVLS...HOWEVER WITH A DEEP SNOWPACK IN PLACE AND SOME AGEOSTROPHIC
DRAINAGE FLOW POSSIBLE...WILL NEED TO WATCH FOR MIXED P-TYPE
ISSUES. IN ANY CASE...A BLEND OF WARMER DETERMINISTIC ECMWF AND
GFS WITH THE COOLER MEMBERS FROM BOTH ECENS AND GEFS WILL SHOW THE
POTENTIAL RANGE. WILL USE THIS BLEND FOR THE REMAINDER OF THE
FORECAST AS WELL.

DETAILS...

SAT NIGHT INTO SUN...
DRY WX PREVAILS AS 1030+ HPA HIGH PRES CRESTS ACROSS THE REGION
EARLY SUN. OVERNIGHT MINS ARE LIKELY TO DIP INTO THE SINGLE DIGITS
BLOW AND ABOVE ZERO UNDER THE WEAK WINDS AND DEEP SNOWPACK.
MODERATING TEMPS UNDER WEAK WARM ADVECTION SUN...BUT HIGHS ARE
STILL LIKELY TO BE BELOW NORMAL...MAINLY IN THE 30S.

SUN NIGHT INTO MON...
LOW PRES WILL PASS THROUGH NRN NEW ENGLAND...ALLOWING A COLD
FRONTAL PASSAGE SUN NIGHT INTO MON THROUGH SRN NEW ENGLAND. NOTING
MODERATE ISENTROPIC LIFT IN ADVANCE OF THE FRONT...ALONG WITH MID
LVL F-GEN ASSOCIATED WITH THE FROPA ITSELF. THESE TWO SOURCES OF
LIFT LOOK TO ACT JUST BELOW /BUT ALSO SOMEWHAT WITHIN/ THE PEAK
DENDRITE ZONE AND THERMAL PROFILES IN THE LOWER LVLS ARE ALL COLD
ENOUGH FOR SNOW. THEREFORE...GIVEN QPF VALUES RANGE FROM ABOUT 0.2
INCHES TO ABOUT 0.5...ADVISORY LEVEL SNOWFALLS ARE LIKELY. IT IS
LIKELY THAT ACCUMULATION WILL HAVE BEGUN BEFORE...AND CONTINUE
DURING THE MONDAY MORNING COMMUTE.

MON NIGHT INTO TUE...
ANOTHER BRIEF RIDGE OF HIGH PRES MOVES OVER THE REGION. FAST
MOVING EMBEDDED WITHIN CONFLUENT FLOW ALOFT. LOW LVL THERMAL
PROFILES SUPPORT TEMPS REMAINING BELOW NORMAL.

TUE NIGHT INTO WED NIGHT...
AS MENTIONED ABOVE...AND NOTED BY THE PREVIOUS FORECASTER...THERE
REMAINS A FAIR AMOUNT OF UNCERTAINTY WITH YET ANOTHER LOW PRES
SYSTEM PASSING TO THE NW. WITH THE POTENTIAL FOR PHASING OF THE
STREAMS ALOFT...IT IS DIFFICULT TO DETERMINE EXACTLY WHERE THE LOW
PRES WILL MOVE OR WHETHER A SECOND LOW WILL FORM. ANY SLIGHT
ADJUSTMENT IS LIKELY TO MAKE SIGNIFICANT CHANGES IN THE THERMAL
PROFILES...BUT THE RECENT TRENDS SUGGEST MID LVL WARMING WITH H85
TEMPS LIKELY EXCEEDING 0C THROUGHOUT MUCH OF SRN NEW ENGLAND. WITH
DEEP SNOWPACK...THIS IS LIKELY TO LEAD TO MIXED PRECIP TYPES AND A
POTENTIAL FOR ICING. IT COULD START AS SNOW THOUGH...AS EVEN THE
WARMEST OF THE AVAILABLE GUIDANCE BEGINS COLD ENOUGH FOR SNOW AT
THE FIRST QPF ONSET. GIVEN THIS DOES SEEM TO HAVE SOME CONNECTION
TO THE SRN STREAM...THE INFUSION OF MOISTURE WITH PWATS
POTENTIALLY 2-3 STD DEVIATIONS ABOVE NORMAL SUGGESTS THAT WARNING
LEVEL SNOW IS NOT OUT OF THE QUESTION FOR AREAS THAT MAINTAIN SNOW
LONGER...WITH SOME ICE ACCRETION. WILL NEED TO CONTINUE TO WATCH
THIS STORM AS WE APPROACH. HEAVY RAIN NOT OUT OF THE QUESTION
EITHER IF A FULL CHANGE OVER IS ALLOWED /THE FURTHER SRN REACHES
HAVE THE BEST CHANCE OF THIS/.

LATE NEXT WEEK...
ONCE AGAIN IT/S DEPENDENT ON WHETHER EACH OF THE STREAMS PHASE.
IF THEY DO SO...IT/S POSSIBLE THE LOW PRES/FRONTAL SYSTEM WILL BE
RATHER SLOW MOVING AND MAY LINGER INTO THU POTENTIALLY. IN ANY
CASE...IT APPEARS ANOTHER INTRUSION OF ARCTIC AIR WILL IMPACT THE
REGION TOWARD THE END OF THE WEEK.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TODAY THROUGH SATURDAY AFTERNOON/...

THROUGH TONIGHT...HIGH CONFIDENCE.
VFR. A FEW MID AND HIGH CLOUDS TODAY...WITH SOME BKN LOW END VFR
CIGS POSSIBLE NEAR THE CAPE.

SATURDAY...HIGH CONFIDENCE. VFR

KBOS TAF...HIGH CONFIDENCE. VFR.

KBDL TAF...HIGH CONFIDENCE. VFR.

OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...

SATURDAY NIGHT INTO SUNDAY...HIGH CONFIDENCE.
MAINLY VFR. CIGS SLOWLY DIMINISH DURING THE DAY ON SUN.

SUN NIGHT INTO MON NIGHT...MODERATE CONFIDENCE.
A COLD FRONTAL PASSAGE WILL BRING ABOUT ACCUMULATING SNOWFALL AT
AREA TERMINALS. EXPECTING 2-5 INCHES AT THIS TIME. PERIODS OF
IFR/MVFR LIKELY WITH GUSTY NW WINDS ON MON...20-30 KT AT TIMES.

TUE...HIGH CONFIDENCE.
MAINLY VFR.

&&

.MARINE...
FORECASTER CONFIDENCE LEVELS...

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

SHORT TERM /TODAY THROUGH SATURDAY AFTERNOON/...HIGH CONFIDENCE.

TODAY THROUGH SATURDAY AFTERNOON...HIGH PRESSURE WILL CONTINUE TO
BUILD IN FROM THE WEST.  THIS WILL KEEP WIND GUSTS GENERALLY UNDER
20 KNOTS THROUGH SAT AFTERNOON.  HOWEVER...WILL NEED TO CONTINUE
SMALL CRAFT ADVISORIES FOR HAZARDOUS SEAS ACROSS OUR OUTER-WATERS
INTO EARLY SAT MORNING.  THIS IS FOR 3 TO 6 FOOT SEAS AS A RESULT OF
LEFT OVER EASTERLY SWELL.

OUTLOOK...SATURDAY NIGHT THROUGH TUESDAY...

SATURDAY NIGHT INTO SUNDAY...HIGH CONFIDENCE.
HIGH PRES OVER THE WATERS. WINDS AND SEAS GENERALLY BELOW SMALL
CRAFT ADVISORY CRITERIA.

SUN NIGHT INTO MON NIGHT...MODERATE CONFIDENCE.
A COLD FRONT CROSSES THE WATERS ON MONDAY. THIS WILL BRING A
PERIOD OF SNOW /MIXING WITH RAIN ON THE SOUTH COAST/. EXPECT
SOUTHERLY WINDS AND BUILDING SWELL SUN NIGHT INTO EARLY MON...WITH
SMALL CRAFT ADVISORY CONDITIONS LIKELY. HOWEVER AFTER THE FRONTAL
PASSAGE AND WINDS SHIFTING TO THE W-NW GALE FORCE WINDS POSSIBLE.

TUESDAY...MODERATE CONFIDENCE.
CONDITIONS IMPROVE BUT SMALL CRAFT ADVISORIES ARE LIKELY TO
CONTINUE.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST SATURDAY FOR ANZ250-
     254>256.

&&

$$
SYNOPSIS...FRANK/DOODY
NEAR TERM...FRANK/DOODY/RLG
SHORT TERM...FRANK
LONG TERM...DOODY
AVIATION...FRANK/DOODY
MARINE...FRANK/DOODY