057 FXUS61 KBOX 291106 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 706 AM EDT MON APR 29 2013 .SYNOPSIS... HIGH PRESSURE WILL REMAIN PARKED OVER NEW ENGLAND THROUGH THE UPCOMING WEEK. THIS WILL BRING SEASONABLY MILD DAYS...COOL NIGHTS...AND NO APPRECIABLE RAINFALL. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 700 AM UPDATE... MINOR CHANGES TO THE FORECAST...BUT OVERALL GENERALLY REMAINS THE SAME. WATCHING PRECIP MOVING ACROSS NJ AND NYC...THESE SHOWERS ARE GENERALLY STATIONARY WITH SLIGHT EASTWARD MOVEMENT. PLENTY OF DRY AIR IN PLACE ACROSS SNE THAT SHOWERS WILL ERODE. HOWEVER CANNOT RULE OUT A SPOT SHOWER ACROSS THE CT VALLEY REGION. THEREFORE HAVE SHIFTED POPS SLIGHTLY INTO CT. ALSO HAVE INCREASED SKY COVER TO ACCOUNT FOR THE HIGH CIRRUS AND APPROACH MID-LEVELS CLOUDS. OTHER CHANGES...AS MIXING BEGINS...DEWPOINTS WILL DROP AND WIND GUSTS WILL INCREASE. HAVE INCREASED GUSTS FOR THE AFTERNOON HOURS. PREVIOUS DISCUSSION... HIGH PRESSURE REMAINS IN PLACE SURFACE AND ALOFT. A SHORTWAVE FROM THE OHIO VALLEY TRIES TO MOVE THROUGH THE RIDGE. SURFACE PRESSURES ARE FORECAST TO FALL LATE MORNING THROUGH THE AFTERNOON...SUGGESTING THE TROUGH WILL MAKE SOME HEADWAY INTO NEW ENGLAND. HOWEVER THE LOWER LEVELS REMAIN RATHER DRY WITH DEWPOINTS IN THE 30S. THE MOIST LOW LEVEL DEWPOINTS ASSOCIATED WITH THE PCPN NEVER GET INTO OUR AREA. CONSENSUS OF MODEL PCPN FIELDS SHOW MEASURABLE PCPN TO THE NEW YORK BORDER AT 12Z...POSSIBLY GETTING ALL THE WAY TO HARTFORD COUNTY BY EVENING. WE ARE MAINTAINING SLIGHT CHANCE POPS OVER THE EXTREME WEST END OF HARTFORD COUNTY AND ALONG THE EAST SLOPES OF THE BERKSHIRES THIS AFTERNOON AND EVENING...BUT EXPECT THE BULK OF ANY MEASURABLE SHOWERS TO REMAIN BLOCKED TO OUR WEST AND SOUTHWEST. WITH THE HIGH TO OUR EAST...EXPECT A SOUTH TO SOUTHEAST FLOW. THIS WILL SUPPORT DEVELOPING SEABREEZES ALONG THE COASTS. MAX TEMPS ARE A BLEND OF MOS. WARMEST VALUES SHOULD WHERE THE HIGH CLOUDS ARE THINNEST AND COOLEST WHERE THE AIRFLOW COMES OFF THE OCEAN. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... TONIGHT... THE WEAK UPPER SHORTWAVE MOVES PAST DURING THE NIGHT. AT THIS POINT THE SURFACE PRESSURES ARE FORECAST TO RISE. SO THERE WILL REMAIN A WINDOW OF OPPORTUNITY FOR SHOWERS TONIGHT. MODEL QPF FIELDS DO SHOW VERY LIGHT BUT MEASURABLE AMOUNTS IN THE CT VALLEY. HOWEVER DEWPOINTS ARE EXPECTED TO REMAIN AS IS...SO DEWPOINT DEPRESSIONS WILL REMAIN WIDE ENOUGH FOR EVAPORATION TO BE A FACTOR. SO THE CHANCE OF MEASURABLE PCPN...WHILE NON- ZERO...WILL CONTINUE LOW AND MOSTLY FOCUSED IN THE WEST. WE WILL CONTINUE WITH SLIGHT CHANCE POPS IN THE CT VALLEY/EAST SLOPE AREAS WITH VALUES DIMINISHING AFTER MIDNIGHT. TEMPS ARE A BLEND OF MOS. TUESDAY... SHORTWAVE MOVES OFF TO THE SOUTHEAST...AND THE SURFACE AND UPPER RIDGE REBUILD OVER NEW ENGLAND. THIS POINTS TO A DRY DAY WITH INCREASING SUNSHINE AS THE SUBSIDENCE EATS AWAY AT THE MID AND HIGH LEVEL CLOUDS. THE SURFACE FLOW REMAINS LIGHT AND SOUTHEAST...WHICH WILL AGAIN ALLOW FOR ONSHORE FLOW AT THE COAST. TEMPS ARE A BLEND OF MOS WITH WARMEST VALUES INLAND AND COOLEST ALONG THE COAST. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... HIGHLIGHTS... * STRONG HIGH PRESSURE AND NEAR OR ABOVE AVG TEMPS. * POSSIBLE BACK DOOR COLD FRONT FRIDAY. * NO SIGN IN A PATTERN CHANGE IN THE PERIOD. CONFIDENCE LEVEL/MODEL GUIDANCE... NO MAJOR CHANGES IN THE FORECAST FOR THE EXTENDED. OVERALL 00Z MODEL GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT IN THE OVERALL PATTERN. MODELS CONTINUE TO ADVERTISE DIGGING TROUGH IN THE CENTRAL CONUS ALLOWING FOR A STRONG RIDGE TO DEVELOP OVER THE NORTHEAST. THIS RIDGE IS AT LEAST 3 STANDARD DEVIATIONS AWAY ALLOWING FOR HIGH CONFIDENCE IN THE FORECAST. BY FRIDAY AN OMEGA BLOCKING PATTERN WILL COME TO PLAY AS AN UPPER LEVEL LOW DROPS FROM NORTH TO SOUTH ACROSS THE ATLANTIC. MODELS SHOW VERY LITTLE IN OVERALL PATTERN CHANGE. APPEARS THAT HIGH PRESSURE WILL REMAIN OVER SNE FOR SOMETIME. DUE TO THE STRONG HIGH PRESSURE HAVE HIGH CONFIDENCE IN DRY WEATHER AND GENERALLY AT OR ABOVE AVG TEMPS. DETAILS... TUESDAY NIGHT THROUGH THURSDAY... DEEP TROUGH WILL DIG ACROSS THE CENTRAL CONUS BY THE MID WEEK ALLOWING FOR SNOW IN PART OF THE PLAINS AND MID-WEST. THIS LARGE TROUGH WILL EVENTUALLY DEVELOP A CUT OFF LOW ACROSS THE CENTRAL PLAINS REGION. HERE IN NEW ENGLAND...THIS ALLOWS FOR A STRONG RIDGE TO BUILD OVER THE EASTERN GREAT LAKES AND THEREFORE HIGH PRESSURE. EXPECT A DRY FORECAST AND TEMPS ABOVE AVG ACROSS THE INTERIOR...COOLER ALONG THE COAST DUE TO ONSHORE FLOW. MAIN WEATHER THREAT HOWEVER IS FIRE WEATHER CONCERNS...SEE BELOW FOR MORE DETAIL. FRIDAY INTO THE WEEKEND... OMEGA BLOCKING PATTERN WILL DEVELOP BY LATE THUS AND INTO FRIDAY. AS THE PATTERN SETS UP A LOW PRESSURE SYSTEM WILL DROP ON THE EASTERN SIDE OF THE RIDGE...JUST EAST OF SOUTHERN NEW ENGLAND. ALTHOUGH BELIEVE THAT DRY WEATHER WILL PREVAIL THIS SYSTEM WILL ALLOW FOR THE OPPORTUNITY OF A BACKDOOR COLD FRONT TO DROP THROUGH ON FRIDAY. THIS WILL ALLOW FOR TEMPS TO DROP BACK TO OR JUST BELOW AVERAGE DUE TO THE ONSHORE FLOW COMBINED WITH COOLER TEMPS ALOFT. FOR NOW CONTINUED TO TREND THE TEMPS DOWN IN THE FORECAST. AFTER THE FRONT PUSHES THROUGH HIGH PRESSURE WILL BUILD AGAIN AND TEMPS WILL JUMP BACK TO OR ABOVE AVERAGE FOR THE WEEKEND AND INTO EARLY NEXT WEEK. DRY WEATHER WILL CONTINUE. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE FOR VFR CONDITIONS THROUGH TUESDAY. EXPECT SOUTHERLY AIRFLOW WILL BE GENERALLY LIGHT ENOUGH FOR A SEA BREEZE TODAY. LOW PROBABILITY OF MVFR CONDITIONS IN LATE NIGHT FOG TONIGHT...MAINLY SOUTH COAST/ISLANDS. KBOS TERMINAL...HIGH CONFIDENCE IN TAF. HIGH CONFIDENCE IN TIMING OF SEA BREEZE. KBDL TERMINAL...HIGH CONFIDENCE IN TAF. LOW PROB OF AN ISOLATED SHOWER. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUESDAY NIGHT-FRIDAY...HIGH CONFIDENCE. VFR THROUGH THE PERIOD WITH ONSHORE FLOW. LOW PROBABILITY OF MVFR VSBYS IN LATE NIGHT VALLEY FOG. && .MARINE... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. HIGH CONFIDENCE THROUGH TUESDAY. HIGH PRESSURE OVERHEAD WILL KEEP WINDS/SEAS BELOW SCA THRESHOLDS THROUGH THE PERIOD. LOW CONFIDENCE THAT FOG WITH VSBYS OF 1 MILE OR LESS ON THE WATERS SOUTH OF RHODE ISLAND MAY REDEVELOP FOR TONIGHT/EARLY TUESDAY. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... HIGH CONFIDENCE THROUGH THE PERIOD. TUESDAY NIGHT INTO THURS...EXPECT CONDITIONS BELOW SMALL CRAFT CRITERIA. HIGH PRESSURE REMAINS WITH DRY WEATHER AND GOOD VSBYS. THURS NIGHT INTO FRIDAY...OFFSHORE LOW PRESSURE WILL INCREASE THE EASTERLY SWELL ALLOWING FOR SEAS TO BUILD ABOVE 5FT. HIGHEST CONFIDENCE FOR SCA IS ACROSS THE OUTER WATERS. OTHERWISE HIGH PRESSURE REMAINS WITH DRY WEATHER AND GOOD VSBYS. && .FIRE WEATHER... MAINLY DRY WEATHER WITH NO APPRECIABLE RAINFALL IS ANTICIPATED THROUGH THE UPCOMING WEEK AS HIGH PRESSURE WILL DOMINATE ACROSS THE REGION. MINIMUM AFTERNOON RELATIVE HUMIDITIES FOR THE WEEK SHOULD REACH BETWEEN 20 AND 35 PERCENT ACROSS THE INTERIOR. UPPER LEVEL RIDGING WILL KEEP WIND SPEEDS BELOW FIRE WEATHER HEADLINE CRITERIA MUCH OF THE TIME...BUT CAN/T RULE OUT A DAY OR TWO WHERE IT GETS CLOSE. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...NONE. && $$ SYNOPSIS...WTB/DUNTEN NEAR TERM...WTB/DUNTEN SHORT TERM...WTB LONG TERM...DUNTEN AVIATION...WTB/DUNTEN MARINE...WTB/DUNTEN FIRE WEATHER...