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FXUS61 KBOX 060614
AFDBOX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TAUNTON MA
114 AM EST MON FEB 6 2012
.SYNOPSIS...
A WARM FRONT MOVES NORTHEAST OF NEW ENGLAND BRINGING A MILD WEST
TO SOUTHWEST WIND. A COLD FRONT WILL SLIDE ACROSS SOUTHERN NEW
ENGLAND ON TUESDAY. HIGH PRESSURE THEN BUILDS FROM CANADA ON
WEDNESDAY. LOW PRESSURE MOVING OUT OF THE SOUTHERN PLAINS MAY
BRING PRECIPITATION OUR WAY WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
10 PM UPDATE...
CLOUDS MOVING INTO NORTHERN NEW ENGLAND AND NORTHERN NEW YORK.
EXTRAPOLATION BRINGS THEM INTO CHESHIRE AND FRANKLIN COUNTIES 06Z
TO 08Z WITH 50 PCT SKY COVER NORTH OF THE MASS PIKE BY SUNRISE. WE
MADE MINOR ADJUSTMENTS TO TEMPS AND DEWPOINTS AS WELL AS SKY COVER
BUT THE THEME REMAINS THE SAME.
PREVIOUS DISCUSSION...
HIGH PRES PRESENTLY CENTERED OVER UPSTATE NY WILL SLIDE SWD IN
CONCERT WITH A RGN OF HIGHEST PRES RISES IN WAKE OF A MID-LVL POS
TILTED TROF AXIS SWEEPING SEWD OUT TO SEA. THIS WILL ALLOW A WEAK
WARM FRNT ATTENDANT TO A ERN CANADIAN SFC LOW TO SLIDE NEWD THRU
THE RGN AIDED BY RETURN W-SWLY FLOW ALONG THE N AND W PERIPHERY OF
THE RETREATING HIGH PRES. WLY FLOW WILL VEER OUT OF THE SW AT THE
SFC WITH PASSAGE. THE BETTER CHCS FOR CLOUDS WILL BE THRU NRN NEW
ENGLAND /COLLOCATED WITH BETTER THETAE MOIST TONGUE AND ISENTROPIC
LIFT ALONG THE 280-290K THETA SFCS/. MID-UPR LVL CLOUDS SHOULD
FILTER ACROSS CENTRAL NEW ENGLAND /N AND E MA AS WELL AS S NH/.
CONSIDER CLOUDS AND ONSHORE SW FLOW...MINS ARE NOT EXPECTED TO
CHANGE MUCH FOR THE S/E. UPR 20S TO LOW 30S CLOSER TO THE
WATERS...WITH UPR TEENS INTO THE MID 20S NW TO SE THRU THE
INTERIOR /RADIATIONAL COOLING LIMITED BY SFC WINDS AND MID-LVL
CLOUDS/.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
MONDAY...
SOUTHWEST FLOW CONTINUES UNDER THE INFLUENCE OF HIGH PRES. WAA ALOFT
WITH H925 TEMPS AVERAGING +2C AT MAX HEATING OF THE DAY. WITH THE
EXPECTATION OF ABUNDANT SUNSHINE...WENT WARM WITH MAX TEMPS RANGING
FROM THE UPR 40S TO LOW 50S /WILL KEEP IT SLIGHTLY COOLER S AND E
WITH ONSHORE FLOW...SEA SFC TEMPS RANGE AROUND THE LOW 40S/. A MAIN
CONCERN FOR THIS TIME PD WILL BE THE WIND. WITH AN APPROACHING TROF
AXIS OUT OF THE HUDSON BAY RGN AND A RIDGE OF HIGH PRES THRU THE
MID-ATLANTIC...THE PRES GRADIENT BETWEEN SHOULD TIGHTEN. MDL SOLNS
FCST H925 WINDS AROUND 35 MPH /EXPECTING LLVLS TO MIX TO H9/. HAVE SW
GUSTS THRU THE INTERIOR OF AROUND 25 MPH...WITH GUSTS OF AROUND 30
MPH OVER THE WATERS. WILL BE LOOKING AT A STRONG SUSTAINED FLOW
OVER THE WATERS /SEE THE MARINE DISCUSSION BELOW FOR FURTHER
DETAILS/.
MONDAY NIGHT...
SW FLOW CONTINUING ALONG AND AHEAD OF AN APPROACHING SFC COLD FRNT
AND MID-LVL TROF AXIS. LOOKING AT FRNL PASSAGE AROUND THE EARLY
MORNING HRS TUE WITH SFC FLOW BACKING OUT OF THE W-NW. COLD FRNT
ITSELF EXHIBITS ANAFRONT CHARACTERISTICS PER MDL SOLNS AS CLOUDS
AND PRECIP REMAIN ALONG THE BACKSIDE OF THE FRNT. CROSS SECTIONS
INDICATE A FAIR AMOUNT OF LIFT AHEAD OF THE FRNT SLOPING BACK TO
TOWARDS THE REAR. WILL SEE INCREASING CLOUDS AS THE FRNT DRAWS
CLOSER /LOOKING AT A START TIME AROUND MIDNIGHT/. AIRMASS MAINLY
CONTINENTAL-POLAR SO SHOULD BE A DRY FCST /NOT EXPECTING ANY
PRECIP WITH THIS FRNT/. CAA BEGINNING AFTER MIDNIGHT. MIN TEMPS
IN THE MID 20S N/W WITH MID 30S S/E.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGHLIGHTS...
* QUIET WEATHER EXPECTED THROUGH MID-WEEK
* LOW PROBABILITY OF A STORM LATE NEXT WEEK
OVERVIEW AND MODEL PREFERENCES...
05/12Z GUIDANCE IS IN REASONABLE AGREEMENT THROUGH WEDNESDAY
NIGHT...THEN THE DIFFERENCES AMONGST THE GUIDANCE MEMBERS BECOMES
MORE SIGNIFICANT. THE PROBLEMS STEM FROM THE EVOLUTION OF A HIGHLY
AMPLIFIED MID-LEVEL FLOW OVER THE WESTERN USA AS WELL AS A POLAR
VORTEX OVER EASTERN CANADA. 05/12Z GFS IS THE SLOWEST TO BREAKDOWN
A LONGWAVE RIDGE IN THE NORTHERN STREAM ACROSS THE WESTERN USA
LATE THIS WEEK...WHICH RESULTS IN IT MAINTAINING A LOWER AMPLITUDE
MID-LEVEL TROUGH OVER THE EASTERN USA. BOTH THE 05/12Z GLOBAL CMC
AND ECMWF MODELS ARE MORE AMPLIFIED...WITH THE ECMWF BEING THE
MOST AMPLIFIED SOLUTION...EVEN DRAGGING A POLAR VORTEX AS FAR
SOUTH AS QUEBEC. SHOULD THIS SOLUTION VERIFY...IT WOULD BE VERY
COLD ACROSS SOUTHERN NEW ENGLAND LATE THIS WEEK INTO NEXT WEEKEND.
GIVEN THE WINTER PATTERN WE HAVE HAD THUS FAR ACROSS SOUTHERN NEW
ENGLAND...AS WELL AS THE ECMWF BIAS TO BE OVERLY AMPLIFIED TOWARD
THE LATER TIME PERIODS OF ITS RUNS...PREFER TO USE A SOLUTION MORE
AMPLIFIED THAN THE GFS AND LESS AMPLIFIED THAN THE ECMWF. THIS
WOULD MAINTAIN A PRIMARY STORM TRACK FARTHER SOUTH OR OFFSHORE
THAN RECENT PAST RUNS. WILL STILL HAVE TO CONTEND WITH A FEW COLD
FRONTS...BUT MOISTURE LOOKS TO BE A LIMITATION WITH MOST OF THEM.
DETAILS...
TUESDAY...
STILL EXPECTING A ROBUST COLD FRONT TO CROSS SOUTHERN NEW ENGLAND
DURING THE AFTERNOON AND EVENING. MOISTURE IS QUITE SHALLOW WITH
THIS FRONT SO SHOULD ONLY SEE AN INCREASE IN CLOUDS AT MOST
LOCATIONS. THAT SAID CANNOT RULE OUT THE POSSIBILITY OF A FLURRY OR
SPRINKLE ACROSS THE HIGHER TERRAIN WHERE THE UPSLOPE FLOW PROVIDES
MORE ENHANCEMENT TO THE VERTICAL LIFT. CONFIDENCE IN THESE
FLURRIES/SPRINKLES DEVELOPING IS LOW...SO HAVE LEFT OUT OF THE
FORECAST FOR NOW.
TUESDAY NIGHT INTO THURSDAY....
EXPECTING A SURFACE HIGH PRESSURE TO BUILD INTO THE GREAT LAKES
DURING THIS PERIOD. SHORTWAVE ENERGY MOVING THROUGH THE SOUTHERN
STREAM OF THE MID- LEVEL FLOW FORECAST TO AMPLIFY A LONGWAVE
TROUGH OVER THE GULF COAST...WHICH IN TURN BACKS THE FLOW OVER THE
NORTH ATLANTIC TO MORE OF A SOUTHWEST DIRECTION. THIS SHOULD SHUNT
A WEAK LOW PRESSURE WELL SOUTH AND EAST OF NEW ENGLAND DURING THIS
TIME. 05/12Z ECMWF IS THE FARTHEST WEST AND SLOWEST WITH THE
TRACK AND TIMING OF ITS LOW PRESSURE...OWING TO ITS MORE AMPLIFIED
MID-LEVEL FLOW. STAYED CLOSER TO THE GREATER MODEL CONSENSUS WITH
THIS FEATURE.
THURSDAY NIGHT INTO SUNDAY...
THE HIGH PRESSURE WHICH SHOULD DOMINATE OUR MID-WEEK WEATHER IS
EXPECTED TO SHIFT FARTHER OFFSHORE THURSDAY NIGHT INTO FRIDAY...
OPENING THE DOOR FOR A COLD FRONT TO PASS THROUGH OUR REGION. THE
TIMING IS VERY MUCH IN QUESTION...BUT LOOKS MOST LIKELY TO HAPPEN
SOMETIME FRIDAY NIGHT INTO SATURDAY. THERE IS THE POSSIBILITY FOR
A WEAK LOW PRESSURE TO TRAVERSE THIS FRONT AS WELL. AT THIS POINT
ONLY WENT WITH A CHANCE OF SNOW OR RAIN SHOWERS UNTIL THE DETAILS
CAN BE BETTER DETERMINED. CONFIDENCE REMAINS LOW DURING THIS
PERIOD OF THE FORECAST...WHICH WILL LIKELY CHANGE IN THE COMING
DAYS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
REST OF TONIGHT...
HIGH CONFIDENCE VFR. WARM FRONT LIFTS NORTHEAST WITH AN AREA OF
CLOUDS AROUND 10 THOUSAND FEET...MAINLY AREAS NORTH OF THE MASS
TURNPIKE. THESE CLOUDS SHOULD MOVE OUT TOWARD MORNING. WINDS
VEERING GRADUALLY OUT OF THE WEST.
MONDAY...
VFR. HIGH CONFIDENCE. MOSTLY CLEAR. ENOUGH OF A PRESSURE GRADIENT
FOR 10 TO 15 KNOT WEST TO SOUTHWEST WINDS. DAYTIME HEATING WILL
ALSO DRAW SOME 25 KNOT GUSTS TO THE SURFACE.
MONDAY NIGHT...
VFR. HIGH CONFIDENCE. COLD FRONT DROPS THROUGH NORTHERN NEW
ENGLAND AND APPROACHES NORTHERN PARTS OF OUR AREA TOWARD MORNING.
LIMITED MOISTURE...SO FEW CLOUDS AND NO PRECIPITATION.
TUESDAY...
VFR. HIGH CONFIDENCE. POTENTIAL FOR CLOUDS BETWEEN 3000 AND 5000
FEET.
KBOS TERMINAL...
HIGH CONFIDENCE VFR. WEST TO SOUTHWEST WINDS TODAY AND
TONIGHT...BECOMING NORTHWEST AROUND 10 KNOTS TUESDAY.
OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...
WEDNESDAY...MODERATE CONFIDENCE VFR. LOW CONFIDENCE IFR CIGS
DEVELOP ALONG THE EAST COAST...POSSIBLY IMPACTING KBOS...KFMH...
KHYA AND KACK.
THURSDAY...MODERATE CONFIDENCE VFR. LOW PRESSURE MAY BRING SOME
MVFR CIGS AND VSBYS IN SNOW/RAIN DURING THE DAY...ESPECIALLY
TOWARD CAPE COD AND NANTUCKET.
FRIDAY...MODERATE CONFIDENCE VFR.
&&
.MARINE...
TONIGHT...
WINDS AND SEAS REMAINING BELOW SMALL CRAFT ADV. HIGH PRESSURE WITH
LIGHT AND VARIABLE FLOW.
MONDAY...
STRONG PRES GRADIENT ACROSS THE WATERS WILL INVOKE MODEST SWLY FLOW
BEGINNING BY MORNING WITH GUSTS 25 TO 30 KTS /ALL WATERS AFFECTED/.
CANT RULE OUT AN ISOLATED GALE FORCE GUST OVER THE OUTER WATERS.
SEAS BUILDING 6-8 FEET ALONG THE OUTER WATERS BY DUSK...WITH 3-5
FEET FOR THE BAYS AND SOUNDS. INNER HARBORS SHOULD REMAIN 1-3 FEET.
MONDAY NIGHT...
WHILE WINDS WILL DIMINISH CLOSER TO SHORE...EXPECTING CONTINUED SWLY
GUSTS AROUND 25 KTS FOR THE OUTER WATERS AS A SFC COLD FRNT
APPROACHES THE WATERS BY TUE MORN. SEAS TO REMAIN CHOPPY...LESSENING
FOR THE E WATERS SOONER WITH EARLIER FRNTL PASSAGE. LOOKING FOR 5-7
FEET ALONG THE OUTER WATERS...WITH 2-4 FEET FOR BAYS AND SOUNDS.
OUTLOOK...TUESDAY THROUGH FRIDAY...
RELATIVELY TRANQUIL WINDS AND SEAS EXPECTED FOR MOST OF THIS PERIOD
AS A HIGH PRESSURE BUILDS ACROSS THE WATERS. ROUGH SEAS COULD
LINGER ACROSS THE OUTER COASTAL WATERS TUESDAY MORNING IMMEDIATELY
BEHIND A COLD FRONT. WINDS SHOULD START TO INCREASE FROM THE
SOUTHWEST FRIDAY AS ANOTHER COLD FRONT APPROACHES THE COASTAL
WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 1 AM EST
TUESDAY FOR ANZ231-232.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR ANZ230-233-234-236.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 8 AM EST
TUESDAY FOR ANZ235-237-256.
SMALL CRAFT ADVISORY FROM 4 AM EARLY THIS MORNING TO 4 AM EST
TUESDAY FOR ANZ250.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR ANZ251.
SMALL CRAFT ADVISORY FROM 4 AM EARLY THIS MORNING TO 8 AM EST
TUESDAY FOR ANZ254-255.
&&
$$
SYNOPSIS...WTB/BELK
NEAR TERM...WTB/BELK/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...BELK
AVIATION...WTB/BELK
MARINE...BELK/SIPPRELL