000
FXUS61 KBOX 110011
AFDBOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
711 PM EST WED MAR 10 2010

.SYNOPSIS...
WEAK HIGH PRESSURE WILL MAINTAIN DRY WEATHER TONIGHT AND MOST OF
THURSDAY ALONG WITH COOLER TEMPERATURES AS CLOUDS AND ONSHORE FLOW
GRADUALLY INCREASE THURSDAY. A LARGE INTENSIFYING LOW PRESSURE SYSTEM
DEVELOPING SLOWLY EAST FROM THE CENTRAL PLAINS WILL REACH THE MID
ATLC COAST THIS WEEKEND AND THEN PUSH EAST OF NEW ENGLAND EARLY NEXT
WEEK. THIS SYSTEM WILL PROBABLY DELIVER A NUMBER OF HAZARDOUS
CONDITIONS TO THE REGION THIS WEEKEND INTO NEXT MONDAY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...

OVERALL PREVIOUS FORECAST ON TRACK WITH CURRENT OBSERVATIONS. AS OF
630 PM MARINE LAYER HAS PENTRATED WELL INLAND ACROSS ALL OF RI AND
THE I495 CORRIDOR OF EASTERN MA. FARTHER INLAND TEMPS WILL ALSO FALL
FAIRLY QUICKLY THIS EVENING GIVEN LOW DEW PTS...LIGHT WINDS AND CLEAR
SKIES. ALTHOUGH THIS TREND WILL LIKELY LEVEL OFF LATER TONIGHT AS MID
AND HIGH CLOUDS OVERSPREAD THE REGION FROM THE SOUTHWEST. SO UPDATED
HOURLY TEMPS AND SKY GRIDS TO REFLECT THESE TRENDS. OTHERWISE
PREVIOUS FORECAST ON TRACK. PREVIOUS DISCUSSION BELOW...

ANOTHER QUIET NIGHT EXPECTED TONIGHT WITH CHILLY TEMPERATURES
AND DRY WEATHER AS HIGH PRESSURE SLIDES SLOWLY OFF THE COAST. EXPECT
INCREASING HIGH CLOUDS THROUGH THE NIGHT. COUPLED WITH HIGHER
DEWPOINTS /RANGING FROM THE SINGLE DIGITS TO THE MID 20S THIS
AFTERNOON/...THIS MAY RESULT IN SLIGHTLY WARMER TEMPERATURES
OVERNIGHT. LOWS WILL STILL BE IN THE UPPER 20S TO MID 30S. USED A
BLEND OF THE LAMP/MAV GUIDANCE FOR TEMPS.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
THE MID LEVEL RIDGE JUST TO THE WEST OF SOUTHERN NEW ENGLAND WILL
CONTINUE TO INFLUENCE OUR WEATHER THROUGH THURSDAY.  THURSDAY SHOULD
BE ANOTHER PLEASANT DAY.  EXPECTING INCREASING CLOUDS...DEPENDING ON
HOW QUICKLY THIS OCCURS TEMPERATURES MAY BE A COUPLE OF DEGREES
COOLER THAN CURRENTLY FORECAST.  WITH MODELS SLOWING DOWN THE
APPROACH OF LOW PRESSURE...KEEPING PRECIP OUT OF SOUTHERN NEW
ENGLAND THROUGH THE DAY.  HAVE CHANCE POPS /10/15Z SREF POPS/ MOVING
INTO THE AREA FROM THE SOUTHWEST AFTER MIDNIGHT THURSDAY NIGHT.
THICKENING CLOUD COVER WILL KEEP OVERNIGHT TEMPERATURES MAINLY IN
THE 30S.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
FORECAST CONFIDENCE REMAINS ABOVE AVERAGE ON LARGE COASTAL LOW
IMPACTING THE REGION THIS WEEKEND INTO EARLY NEXT WEEK. HOWEVER
FORECAST CONFIDENCE IS BELOW AVERAGE ON THE DETAILS REVOLVING AROUND
ONSET OF PRECIP...MAGNITUDE OF QPF AND PTYPE EARLY THIS WEEKEND AND
THEN AGAIN EARLY NEXT WEEK.

POTENTIAL HAZARDS REMAIN THE SAME...HEAVY QPF AND ASSOCIATED
FLOODING...STRONG WINDS...COASTAL FLOODING AND BEACH EROSION ALONG
WITH SOME ICING NORTHWEST MA AND SOUTHWEST NH. HERE ARE THE DETAILS
REGARDING EACH HAZARD...

QPF AND FLOOD POTENTIAL...
UNFORTUNATELY MODELS CONTINUE TO DISPLAY LARGE SCALE DIFFERENCES ON
TRACK OF MID LEVEL CIRCULATION AND CORRESPONDING SURFACE LOW. 12Z
ECMWF IS FARTHEST NORTH WITH VERTICALLY STACKED LOW MOVING INTO
SOUTH COASTAL NEW ENGLAND. THIS SHIFTS THE STRONGEST WIND ANOMALIES
AND PWAT PLUME INTO FROM SOUTHERN NEW ENGLAND LATE SAT/SAT NGT TO NORTHERN
NEW ENGLAND SUN AND MON. THIS RESULTS IN ONLY A BRIEF 12 HR PERIOD OF
HEAVY QPF HERE FROM LATE SAT INTO EARLY SUN MORNING...THEN DRY
SLOTTING THEREAFTER WITH HEAVY QPF MOVING INTO NORTHERN NEW ENGLAND.
OBVIOUSLY THIS WOULD REDUCE THE FLOOD THREAT HERE. HOWEVER THE 12Z
ECMWF IS ON THE NORTHERN EDGE OF THE 12Z GUID WITH THE 12Z GFS ON THE
SOUTHERN EDGE AND THE 12Z GGEM AND UKMET IN THE MIDDLE OF THE PACK.
THE 12Z GEFS IS CLOSER TO THE 12Z ECMWF. SO IN A NUTSHELL THERE IS
ENOUGH MODEL SPREAD HERE TO PLAY THINGS CONSERVATIVE FOR THE MOMENT.

IN ADDITION...EVEN THE NORTHERN EC SOLUTION DOESN/T BRING WARM AIR
INTO THE INTERIOR WHERE A MODEST SNOW PACK EXIST.  THUS IT APPEARS A
LOW PROBABILITY THAT MUCH OF THE SNOW PACK WOULD BE RELEASED GIVEN
COOL SURFACE TEMPS. THEREFORE THE FLOOD THREAT MAY HINGE SOLELY ON
HEAVY QPF WITHOUT ANY CONTRIBUTION FROM SNOW MELT. FURTHERMORE THE
SNOW PACK ACROSS THE BERKSHIRES/NORTHERN WORCESTER HILLS INTO
SOUTHERN NH IS BELOW NORMAL FOR THIS TIME OF YEAR AND WILL LIKELY
CONTINUE TO ERODE OVER THE NEXT FEW DAYS BEFORE THE HEAVIEST QPF
ARRIVES LATE SAT INTO EARLY SUN. THEREFORE NOT EXPECTING MUCH
CONTRIBUTION FROM THE SNOW PACK.

AS MENTIONED ABOVE ANOTHER LIMITING FACTOR FOR FLOODING IS THE 12Z
ECMWF AND TO A LESSER EXTENT THE 12Z GEFS WITH WIND ANOMALIES AND
PWAT PLUME BEING PROGRESSIVE AND TRAVERSING FROM SOUTHERN NEW
ENGLAND INTO NORTHERN NEW ENGLAND SUNDAY...SHUTTING OFF THE HEAVY
QPF ACROSS SOUTHERN NEW ENGLAND.

WHILE WE SHOULDN/T DISMISS THE FLOOD POTENTIAL THREAT FOR THIS
WEEKEND WE NEED TO CONSIDER THESE POSSIBLE LIMITING FACTORS WHICH
WOULD SUGGEST A GREATER RISK FOR MINOR FLOODING. IN
ADDITION...TYPICALLY FLOOD EVENTS HERE IN SOUTHERN NEW ENGLAND
REQUIRE 2 HEAVY QPF EVENTS IN A SHORT PERIOD OF TIME WITH THE FIRST
EVENT BEING THE PRIMER FOR THE SECOND EVENT. OUR LAST LARGE QPF EVENT
IS NOW NEARLY 2 WEEKS AGO. THUS AN EXCESSIVE LONG DURATION QPF EVENT
WILL BE REQUIRED THIS WEEKEND FOR SIGNIFICANT FLOODING. IT REMAINS
POSSIBLE BUT ALL ELEMENTS WILL HAVE TO COME TOGETHER...ESPECIALLY
WITHOUT ANY OR VERY LITTLE CONTRIBUTION FROM SNOW MELT.

REGARDING POPS...MODELS CONTINUE TO TREND SLOWER WITH THE ONSET OF
QPF. THIS SEEMS REASONABLE GIVEN PERSISTENT MEAN TROF OVER SOUTHEAST
CANADA WHICH STALLS MID LEVEL RIDGE OVER NEW ENGLAND. IN
ADDITION...MODELS IN GOOD AGREEMENT ON HOLDING OFF HEAVY QPF HERE
UNTIL LATE SAT...ESPECIALLY EASTERN MA. SO WHILE THERE MAY BE SOME
LIGHT SPOTTY LIGHT RAIN HERE FRI/FRI NIGHT INTO EARLY SAT...OUTDOOR
PLANS MAY BE A GO FRI INTO EARLY SAT GIVEN A WASHOUT IS NOT EXPECTED.

STRONG WIND POTENTIAL...
HIGH LIKELIHOOD OF WIND ADVISORY CRITERIA OF EAST WINDS 30 TO 40 MPH
WITH GUSTS TO 50 MPH ALONG THE COAST. AS THE EVENT NEARS WILL HAVE TO
WATCH POTENTIAL FOR HIGH WIND CRITERIA /GUSTS 60 MPH AND HIGHER/ AS
SOME GUID INDICATING LOW LEVEL JET UP TO 70 KT.

PTYPE...
LOW RISK OF FREEZING RAIN CONTINUES ACROSS THE HIGHER TERRAIN OF
NORTHWEST MA INTO SOUTHWEST NH. RISK IS GREATEST LATE SAT AND SAT
NIGHT. BY SUNDAY SHALLOW COLD AIR SHOULD ERODE/WARM. THEN BY SUN NGT
INTO EARLY NEXT WEEK AS MID LEVEL LOW APPROACHES SOUTHERN NEW
ENGLAND COLUMNS BEGINS TO COOL. THIS MAY SUPPORT SOME WET SNOW
ACROSS THE HIGHER TERRAIN.

COASTAL FLOODING/BEACH EROSION...
WHILE ASTRO TIDES ARE RELATIVELY LOW AND THE GFS SURGE GUIDANCE ONLY
OFFERS 1 FT SURGE...IF WE GET A 2.5 FT SURGE ALONG WITH SEAS NEAR 20
FT THE RISK OF MINOR COASTAL FLOODING EXIST. GIVEN THE STRENGTH OF
THE LOW LEVEL JET AND DURATION OF ONSHORE FLOW...THINK A 2-2.5 FT
SURGE IS NOT OUT OF THE QUESTION ALONG WITH SEAS NEAR 20 FT. IN
ADDITION IF WATER LEVELS BECOME HIGHER THAN PREDICTED BY THE GFS
STORM SURGE MODEL COMBINED WITH LARGE SEAS POUNDING THE
SHORELINE...THERE MAY BE A GREATER RISK OF SIGNIFICANT BEACH
EROSION.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
TODAY...HIGH CONFIDENCE VFR. LOCAL SEABREEZES DEVELOP AFTER 18Z.

TONIGHT...VFR CEILINGS SPREADING ACROSS THE AREA FROM 6000-12000FT
LOWER W.

THURSDAY...VFR CEILINGS 3000-5000FT. SPOTTY -SHRA IN THE AFTERNOON
MAINLY NW MASS AND SW NH.

THURSDAY NIGHT...VFR TO START. MVFR CONDITIONS MAY DEVELOP IN SCT
SHOWERS LATE.

OUTLOOK...

FRI...HIGH CONFIDENCE FOR MVFR WITH A LOW PROB OF IFR IN PERIODS OF
RAIN/DRIZZLE AND FOG.

SAT...MVFR LOWERING TO IFR FROM WEST TO EAST. E G30-40 KTS MASS
COAST WITH ASSTD LLWS. ICE POSSIBLE NORTHWEST MA AND SOUTHWEST NH.
LOW CONFIDENCE ON TIMING OF MVFR TO IFR.

SAT NIGHT...HIGH CONFIDENCE ON IFR IN WIND DRIVEN RAIN. STRONG EAST
WINDS 30-40 KT EASTERN MA ALONG WITH POSSIBLE LLWS.

SUN...HIGH CONFIDENCE IFR/LIFR IN RAIN/DRIZZLE FOG...POSSIBLY
CHANGING TO SNOW AT NIGHT ORH AND OTHER HIGH TERRAIN TERMINALS.

MON...MVFR/IFR IN PERIODS OF RAIN POSSIBLY MIXED WITH SNOW HIGH
TERRAIN TERMINALS.

&&

.MARINE...
A QUIET PERIOD OVER THE MARINE ZONES THROUGH WEDNESDAY NIGHT.  SEAS
WILL REMAIN WELL BELOW 5 FEET AND VARIABLE WINDS 10 TO 15 KTS WILL
PREVAIL.

THURSDAY...WINDS START INCREASING THURSDAY AFTERNOON WITH ISOLATED
WIND GUSTS TO 25KTS.  SEAS INCREASE TO NEAR 5 FEET LATE THURSDAY
NIGHT.

OUTLOOK...
FRI...SCA DEVELOPS LATE WITH INCREASING ESE WINDS AND SEAS.

WEEKEND-MON...EAST GALES LIKELY FROM TIME TO TIME BECOMING NE MONDAY.
SEAS EVENTUALLY BUILD TO 16 TO 22 FT. LOW PROB STORM FORCE GUSTS SAT
NIGHT OR SUN MORNING.

&&

.FIRE WEATHER...
THE CONTINUED DRY PATTERN WILL ALLOW THE MINIMUM RELATIVE HUMIDITY
TO DROP TO BETWEEN 25 AND 35 PERCENT THURSDAY. WINDS/GUSTS WILL
REMAIN BELOW 15 MPH SO NO FIRE WEATHER HEADLINES ANTICIPATED.

&&

.EQUIPMENT...
THE NOAA WEATHER RADIO TRANSMITTER AT BLUE HILL WILL BE OFF THE AIR
THROUGH MOST OF THIS WEEK DUE TO A BROKEN ANTENNA. NEEDED PARTS HAVE
BEEN ORDERED AND THE TRANSMITTER MAY RETURN TO SERVICE THE WEEK OF
MARCH 15TH.

&&

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

&&

$$
SYNOPSIS...NOCERA/RLG
NEAR TERM...NOCERA/RLG - UPDATED 711 PM
SHORT TERM...RLG
LONG TERM...NOCERA - UPDATED 711 PM
AVIATION...NOCERA/RLG
MARINE...NOCERA/RLG
FIRE WEATHER...RLG
EQUIPMENT...STAFF

NWS RAHNWS Office Area Forecast Discussion