000
FXUS61 KBOX 112151
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
451 PM EST THU MAR 11 2010
.SYNOPSIS...
HIGH PRESSURE TO OUR NORTH WILL RESULT IN MAINLY CLOUDY AND COOL
WEATHER TONIGHT AND FRIDAY. A STRONG STORM WILL THEN MOVE OFF THE
MID ATLC COAST BRINGING MAINLY RAIN AND OCCASIONALLY WINDY WEATHER
THIS WEEKEND INTO MONDAY. MUCH NICER WEATHER FOLLOWS BY THE MIDDLE
OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
MAIN BATCH OF MID LEVEL LIFT WORKING ITS WAY THROUGH SOUTHERN
NH/NORTH CENTRAL AND NORTHEAST MA LATE THIS AFTERNOON. SCATTERED
RAIN SHOWERS WERE FALLING THIS REGION. THERE WAS EVEN A BIT OF
SLEET MIXED AS A VERY DRY BOUNDARY LAYER WAS YIELDING EVAPORATIONAL
COOLING. THIS ACTIVITY SHOULD PUSH OFFSHORE EARLY THIS EVENING AND
THE MAJORITY OF THE NIGHT WILL GENERALLY BE DRY. NONETHELESS...WILL
MAINTAIN 15 TO 30 POPS OVERNIGHT AS WEAK WARM ADVECTION MAY CONTINUE
TO PROMOTE A FEW BRIEF PASSING SPRINKLES/LIGHT RAIN SHOWERS.
ALSO...THERE IS A LOW PROBABILITY OF VERY ISOLATED PATCHY LIGHT
FREEZING DRIZZLE LATE TONIGHT OVER THE HIGHEST TERRAIN /EAST SLOPES
OF THE BERKSHIRES AND MONADNOCKS/. THE RECENT MILD WEATHER THOUGH
WILL BE A LIMITING FACTOR IN ANY ROAD PROBLEMS AND THE PRECIPITATION
LOOKS TO BE RATHER SPOTTY. NONETHELESS...THIS IS SOMETHING THAT
WILL HAVE TO BE WATCHED.
LOWS WILL MAINLY BE IN THE 30S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
FRIDAY...
A 1030 MB HIGH PRESSURE SYSTEM OVER EASTERN CANADA WILL BEGIN TO
NOSE DOWN INTO EASTERN NEW ENGLAND. THIS MAY TEMPORARILY SEND A BIT
OF DRIER AIR DOWN FROM THE NORTHEAST INTO OUR REGION.
THEREFORE...DO NOT SEE MUCH THREAT OF PRECIPITATION ON FRIDAY. WILL
GO WITH MAINLY A DRY FORECAST ACROSS OUR NORTHERN/EASTERN
ZONES...WITH JUST SOME 20 TO 30 POPS ACROSS OUR WESTERN/SOUTHERN
ZONES. THE BEST CHANCE OF ANY MEASURABLE LIGHT RAIN SHOWERS WILL BE
ACROSS THE EAST SLOPES OF THE BERKSHIRES...BUT ANY AMOUNTS THAT FALL
SHOULD BE QUITE LIGHT. IN FACT...WOULD NOT BE SURPRISED TO SEE SOME
PEEKS OF SUNSHINE ACROSS OUR NORTHERN AND EASTERN ZONES.
ONSHORE FLOW SHOULD KEEP HIGHS IN THE MID TO UPPER 40S. THE COOLEST
READINGS WILL BE FOUND NEAR SHORE.
FRIDAY NIGHT...
THERE ARE STILL SOME TIMING DIFFERENCES AMONGST THE MODELS.
HOWEVER...THE MODELS DO AGREE IN A DEVELOPING SOUTHEAST LOW LEVEL
JET OVERNIGHT. THIS WILL INDUCE MID LEVEL LIFT AND EXPECT STEADY
RAIN TO OVER SPREAD PORTIONS OF THE REGION FROM SOUTHWEST TO
NORTHEAST OVERNIGHT. WILL INCREASE POPS TO LIKELY ACROSS OUR
SOUTHWEST ZONES TOWARDS 12Z SATURDAY WITH CHANCE POPS BY THEN ACROSS
OUR NORTHEAST ZONES.
THE VAST MAJORITY OF THE PRECIPITATION WILL BE IN THE FORM OF RAIN.
HOWEVER...THERE IS THE POTENTIAL FOR SOME FREEZING RAIN ACROSS THE
HIGHER TERRAIN OF THE EAST SLOPES OF THE BERSHIRES AND THE
MONADNOCKS IN SOUTHERN NH. THE MODELS ARE INDICATING 925 MB
TEMPERATURES BETWEEN 0 AND -2C TOWARDS 12Z SATURDAY WITH A COLD AIR
DAMNING SIGNATURE. SURFACE TEMPERATURES WILL BE MARGINAL AND A LOT
OF THE POTENTIAL WILL DEPEND ON WHEN EXACTLY THE PRECIPITATION
ARRIVES AND THE EXACT TEMPERATURE. HOWEVER...THERE IS A CHANCE THAT
A WINTER WEATHER ADVISORY MAY EVENTUALLY BE NEEDED FOR OUR DISTANT
INTERIOR HIGH TERRAIN.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
NOT MUCH CHANGE ANTICIPATED FROM PREV FCST WITH WEEKEND STORM.
THERE ARE STILL UNCERTAINTIES WITH HOW MID LEVEL LOW EVOLVES AND
THIS HAS IMPACTS ON WIND/QPF FIELD BUT WE HAVE HIGH CONFIDENCE OF
HEAVY RAINFALL EVENT HERE SAT THROUGH SUN. OTHER POTENTIAL HAZARDS
ARE STRONG WIND ALONG THE COAST...DISTANT INTERIOR ICE AND MINOR
COASTAL FLOODING.
VERY COMPLEX UPPER AIR PATTERN WITH NUMEROUS SHORTWAVES ROTATING
AROUND MID LEVEL LOW WHICH WILL MAKE IT VERY DIFFICULT TO RESOLVE
EVOLUTION OF PRIMARY AND SECONDARY LOWS. EVENTUALLY CONSOLIDATED
LOW WILL ORGANIZE NEAR OR SE OF THE BENCHMARK BY EARLY MON. EXACTLY
HOW WE GET THERE IS STILL UNCERTAIN.
WE DO NOT LIKE THE GFS DEPICTION OF STRONG LEAD WAVE ALONG MID ATLC
COAST FOR SAT AFTERNOON/EVENING WHICH RESULTS IN VERY STRONG LLJ
APPROACHING 100 KT AT 850 MB NEAR LONG ISLAND BY 00Z SUN. GFS
APPEARS TO BE DEALING WITH FEEDBACK ISSUES AND MODEL CONSENSUS SHOWS
STRONGER PRIMARY LOW AND WEAKER COASTAL LOW TO THE EAST. WE LARGELY
ARE RELYING ON ECMWF FOR THIS FORECAST WHICH HAS SHOWN GOOD RUN TO
RUN CONSISTENCY.
STEADY RAIN MOVES INTO SNE FROM SW TO NE DURING SAT. THERE IS A LOW
PROB OF SOME FREEZING RAIN/SLEET WHICH COULD REQUIRE WWA ACROSS FAR
NW MA AND SW NH LATE FRI NIGHT OR EARLY SAT IF PRECIP COMES IN BY
12Z SAT AS THERE IS ENOUGH LEVEL COLD AIR IN PLACE. BUT IF THERE IS
ANY DELAY IN THE PRECIP SHIELD...ICING PROBLEMS WOULD BE MINIMIZED
AS SOME WARMING OCCURS DURING THE DAY.
IT APPEARS HEAVIEST OF THE RAINFALL WILL OCCUR SAT NIGHT ACROSS SNE
AS LLJ AXIS MOVES NORTHWARD ACROSS THE REGION. HEAVIER RAINFALL MAY
BEGIN BY SAT AFTERNOON SW ZONES. LLJ BEGINS TO LIFT NORTHWARD LATE
SAT NIGHT SHIFTING TO NORTHERN NEW ENG DURING SUN. BUT SOUTHERN
EDGE OF THE JET REMAINS NEARLY STATIONARY ACROSS N ZONES DURING SUN
WHICH MAY KEEP PERIODS OF HEAVY RAIN ACROSS NE MA AND S NH WHILE DRY
SLOT BRINGS DIMINISHING RAINFALL SOUTH OF THE PIKE DURING SUN.
SOME ICING IS POSSIBLE FAR NW ZONES AGAIN SAT NIGHT AND EARLY SUN AS
LOW LEVEL COLD AIR REDEVELOPS AT NIGHT. ALSO LOW PROB OF SOME WET
SNOW HIGHER ELEVATIONS AS THE COLUMN COOLS AND LOW AND MID LEVEL
THICKNESS PROFILES BECOME MARGINALLY COLD ENOUGH FOR SNOW. BOTH
GFS AND ECMWF SHOW THIS AND IF THERE IS STRONG ENOUGH OMEGA MOVING
ACROSS THE REGION THIS COULD BE ENOUGH TO PRODUCE A PERIOD OF WET
SNOW WITH SOME ACCUM FOR NORTHERN BERKSHIRES AND MONADNOCKS.
CONFIDENCE IS LOW BUT THIS POSSIBILITY WILL NEED TO BE MONITORED
DURING LATER FORECASTS.
SUN NIGHT...MAY SEE SOME MINOR SNOW ACCUM FAR NW ZONES AS ATMOSPHERE
COOLS. ECMWF IS SUGGESTING THIS BUT GFS DRIES IT OUT.
QPF AND FLOOD POTENTIAL...
MOST OF THE MODEL GUIDANCE IS IN VERY GOOD AGREEMENT WITH AXIS OF
MAX RAINFALL NEAR THE I95 CORRIDOR. +4 SD EASTERLY INFLOW IS
IMPRESSIVE WHICH FAVORS HEAVY RAINFALL EVENT BUT PWAT ANOMALY +1/+2
SD NOT AS HIGH AS I WOULD TO SEE IT FOR REAL EXCESSIVE RAINFALL
AMOUNTS. LLJ IS FAIRLY PROGREEIVE WHICH MAY ALSO LIMIT DURATION OF
HEAVIEST RAINFALL TO SAT NIGHT. ALSO GEFS PROBS OF 3"/36HR HAVE
DECREASED AND ARE NOW ZERO. SREF SHOWING 30-50% PROB OF 3" EASTERN
NEW ENG. CURRENT THINKING IS 1-3" RAINFALL EVENT WITH ISOLD 4"
TOTALS. MAX RAINFALL CENTRAL AND EASTERN NEW ENG...POSSIBLY
EXTENDING NORTHWARD TO MERRIMACK BASIN IF HEAVY RAIN PERSISTS IN LLJ
AXIS DURING SUNDAY. CURRENT THINKING IS MODERATE TO HIGH PROB OF
MINOR FLOODING.
STRONG WIND POTENTIAL...
HIGH PROB OF WIND ADVISORY CRITERIA SAT NIGHT...ESPECIALLY NEAR THE
COAST AS EASTERLY LLJ /60-70 KT AT 925 MB/ MOVES NORTHWARD ACROSS
THE REGION. LOW PROB OF HIGH WIND WARNING CRITERIA IF GOOD PRES
FALLS DEVELOP.
COASTAL FLOODING/BEACH EROSION...
WHILE ASTRO TIDES ARE LOW...THINK PERSISTENT GALE FORCE EASTERLY
FLOW WILL BRING STORM SURGE UP TO 2 FEET DURING HIGH TIDE CYCLES
FROM SAT NIGHT THROUGH SUN NIGHT. WITH 20+ FOOT SEAS DEVELOPING
OFFSHORE THIS WOULD BE ENOUGH TO GENERATE MINOR COASTAL FLOODING
ALONG THE EAST COAST WITH LOW PROB OF LOW END MODERATE FOR
SUCCESSIVE TIDE CYCLES.
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.
MONDAY THROUGH THURSDAY...
THE LOW PRESSURE SYSTEM PLAGUING US ALL WEEKEND IS MUCH SLOWER TO
DEPART ON THE ECMWF THAN ON THE GFS. HAVE OPTED FOR THIS SLOWER
SCENARIO WITH THE 990 MB LOW STILL WELL TO THE SOUTHEAST OF
NANTUCKET DURING THE AFTERNOON. SKIES MAY CLEAR OUT TO THE NORTH AND
WEST OF SOUTHERN NEW ENGLAND DURING THE DAY BUT FOR NOW AM EXPECTING
CLOUDINESS HERE WHICH WILL KEEP TEMPERATURES WELL BELOW MAVMOS
VALUES. GFS HAS HIGHS INTO LOWER 50S WITH SUNSHINE BUT HAVE GONE
WITH PREVIOUS FORECAST HIGHS OF 40 TO 45 MOST AREAS AND A CONTINUING
CHANCE OF RAIN...ESPECIALLY IN THE SOUTHEAST. ECMWF TEMPS AT 850 MB
ARE -1C TO -2C WITH AN ISOTHERMAL PROFILE IN THE LOW LEVELS WHICH
COULD MEAN SOME WET SNOWFLAKES TOO...BUT ITS SURFACE TEMPERATURES
ARE IN THE UPPER 30S MOST OF THE DAY WHICH WOULD MEAN MOSTLY RAIN
AND NOTHING STICKING TO THE GROUND. FOR NOW 40 TO 45 SEEMS BEST
COMPROMISE.
FORECAST GETS MUCH EASIER AFTER THAT. SKIES WILL CLEAR LATER MONDAY
NIGHT. HIGH PRESSURE BUILDS INTO THE AREA TUESDAY LEADING TO A FINE
ALMOST-SPRING DAY. WITH ABUNDANT SUNSHINE WE SHOULD REACH HIGHS FROM
53 TO 57 EXCEPT COOLER ON THE CAPE AND ISLANDS.
A COOL FRONT IS FORECAST TO MOVE THROUGH IN THE TUESDAY NIGHT OR
WEDNESDAY TIME FRAME BUT IT WILL BE DRY AND LARGELY UNNOTICED EXCEPT
FOR KICKING UP SOME NORTHERLY WIND GUSTS TO 20 KTS OVER THE WATERS.
HIGH PRESSURE FROM THE OHIO VALLEY TO THE EAST COAST WILL LEAD TO
SUNSHINE WEDNESDAY WITH HIGHS AGAIN NEAR 50. ON THURSDAY...WE ARE
FORECASTING PARTLY SUNNY CONDITIONS...JUST A BIT MORE HIGH
CLOUDINESS IN ASSOCIATION WITH A JET MAXIMUM PASSING ACROSS SOUTHERN
QUEBEC. OUR HIGHS SHOULD REACH 50 TO 55.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
TONIGHT...MODERATE CONFIDENCE IN VFR CONDITIONS DESPITE AN ABUNDANCE
OF MID LEVEL CLOUDINESS. WE MAY SEE SOME MARGINAL MVFR CEILINGS
DEVELOP ACROSS BDL/BAF/ORH TERMINALS AFTER MIDNIGHT.
FRIDAY...MODERATE CONFIDENCE IN MAINLY VFR CEILINGS ACROSS THE
MHT/BOS/FMH/HYA/ACK SITES DESPITE MID LEVEL CLOUDINESS. MODERATE
CONFIDENCE IN MARGINAL MVFR-VFR CEILINGS ACROSS BDL/BAF/ORH/PVD
TERMINALS. EASTERLY WIND GUSTS OF 20 TO 25 KNOTS MAY DEVELOP DURING
THE AFTERNOON TO THE SOUTH OF MA TURNPIKE.
FRIDAY NIGHT...MODERATE CONFIDENCE THAT MVFR-IFR CONDITIONS WILL
OVERSPREAD THE REGION IN RAIN FROM SOUTHWEST TO NORTHEAST.
OUTLOOK...
SAT...MVFR LOWERING TO IFR FROM SW TO NE. E G35 KTS DEVELOPING NEAR
THE COAST. ICE POSSIBLE NORTHWEST MA AND SOUTHWEST NH EARLY SAT.
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 PROBABLE LLWS.
SUN...HIGH CONFIDENCE IFR/LIFR IN RAIN/DRIZZLE FOG...POSSIBLY
CHANGING TO SNOW AT NIGHT ORH AND OTHER HIGH TERRAIN TERMINALS.
MON...MVFR CIGS BECOMING VFR NW HALF. MVFR CIGS AND AREAS OF RAIN OR
RAIN MIXED WITH SOME WET SNOW SE HALF WITH LOCAL IFR CIGS/VSBY IN
THE MORNING. MODERATE CONFIDENCE.
MON NIGHT...HIGH CONFIDENCE OF BECOMING VFR.
TUESDAY...HIGH CONFIDENCE VFR.
&&
.MARINE...
TONIGHT...
WINDS AND SEAS WILL REMAIN BELOW SCA THRESHOLDS WITH WEAK PRESSURE
GRADIENT IN PLACE.
FRIDAY AND FRIDAY NIGHT...
LOW PRESSURE MOVING EAST INTO THE MID ATLANTIC STATES WILL COMBINE
WITH HIGH PRESSURE OVER EASTERN CANADA. THIS WILL RESULT IN AN
INCREASED PRESSURE GRADIENT WITH EASTERLY SCA WIND DEVELOPS
DEVELOPING FRIDAY AND CONTINUING FRIDAY NIGHT ACROSS THE OPEN WATERS.
OUTLOOK...
SAT-MON...E/NE GALES LIKELY FROM TIME TO TIME. SEAS EVENTUALLY BUILD
TO 16 TO 22 FT OUTER WATERS. LOW PROB STORM FORCE GUSTS SAT NIGHT
AND EARLY SUN ASSOCD WITH THE LLJ AND AGAIN MONDAY AS THE ENVELOPE
OF STRONG WINDS WHICH LIFTED N DURING SUNDAY COLLAPSES SEWD WITH THE
DEPARTING STORM.
MON NIGHT-TUE...SEAS SUBSIDE TO 8 TO 12 FT MON NIGHT AND TO 6 TO 10 FT
OVER THE OUTER WATERS TUE. WINDS WILL FINALLY DIMINISH TO BELOW SMALL
CRAFT ADVISORY LEVELS BY LATE TUE AFTERNOON.
&&
.EQUIPMENT...
THE ANTENNA HAS BEEN REPLACED AND NOAA WEATHER RADIO AT BLUE HILL IS
NOW BACK ON THE AIR. AGAIN WE APOLOGIZE FOR ANY INCONVENIENCE WHILE
THIS TRANSMITTER WAS OFF THE AIR FOR THE PAST SEVERAL DAYS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...GALE WATCH FROM SATURDAY MORNING THROUGH SUNDAY MORNING FOR
ANZ231>235-237-254>256.
SMALL CRAFT ADVISORY FROM 10 AM FRIDAY TO 6 AM EST SATURDAY
FOR ANZ231>235-237-250-251-254>256.
GALE WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING FOR
ANZ230-236-250-251.
&&
$$
SYNOPSIS...KJC
NEAR TERM...FRANK
SHORT TERM...FRANK
LONG TERM...KJC/GAF
AVIATION...KJC/FRANK/GAF
MARINE...KJC/FRANK/GAF
EQUIPMENT...GAF
