FXUS61 KBOX 041910 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 310 PM EDT SAT JUL 4 2009 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION BY THIS EVENING WHICH WILL BRING IN A DRY AND SEASONABLY WARM AIRMASS THROUGH SUNDAY. ANOTHER LOW PRESSURE AREA SWINGS ACROSS NEW ENGLAND LATE MONDAY THROUGH WEDNESDAY BRINGING DAYTIME CLOUDS AND SCATTERED SHOWERS. HIGH PRESSURE BRINGS DRIER AND WARMER WEATHER LATE IN THE WEEK. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... 220PM...HAVE REDUCED AREA OF POSSIBLE SHOWERS TO ESSENTIALLY S NH AND THE MERRIMACK RIVER AREA OF FAR NE MASS. YOU CAN SEE THE BACK EDGE ON THE RADAR COVERAGE AS DRIER AIR ENCROACHES...CUTTING OFF CONVECTION OR KEEPING IT SHALLOW WITH NO FURTHER GROWTH. THINK THE THREAT IS ENDED NOW EXCEPT MHT AREA. MANY MODELS WERE TOO ROBUST INTO SNE THIS AFTN AND PREV SEVERAL DAYS...THE UKMET THE BEST-MOST CONSERVATIVE. ALL PRODUCT UPDATES HAVE POSTED. 1146 AM: WE ARE HOLDING ONTO THE CHC TSTM FCST DUE TO CURRENT RADAR TRENDS... INSTABILITY AND 12Z GFS PROJECTED CONVECTIVE PARAMETERS EARLY THIS AFTN. WE TRIMMED THE SRN EDGE SLIGHTLY FURTHER BUT JUST DOING THESE UPDATES HOUR BY HOUR TIL SURE WE CANT HAVE A STRONG STORM. IN MY OPINION... IF IT DOESNT DEVELOP BY 2PM...WE ARE DONE IN MASS AND WOULD BE ALL DONE WITH THUNDER IN MHT REGION IF NIL PRIOR TO 330PM. WE HAD 30 KTS EARLIER AT ORH AND ARD 22 KTS BOS. WIND GUSTS SHOULD INCREASE BETWEEN 3PM AND 6PM AS DRIER AIR SINKS INTO OUR AREA. 915 AM: GRIDS WARMED SLIGHTLY. ADDED HAIL AND GUSTY WINDS TO THE T PTN OF S NH AND NE MASS TODAY AND TRIMMED THE POPS ON THE SRN FLANK S OF THE MA PIKE. PRODUCTS POSTED. 845 AM: EXAMINING ALB SOUNDING FOR 80/57 MIDDAY AND THERE IS A RISK OF A TSTM NE MA AND S NH. IF THEY DEVELOP... WE COULD SEE IT STRONG. MAX TT TDY IN SNE BE CLOSE TO 83F COASTAL PLAIN AND VALLEYS AND WILL ADJUST SHORTLY. HAVE BEEN IN TOUCH WITH SPC. 815 AM UPDATED GRIDS/NOWCAST/ZFP PRODUCTS FOR HIGHER GUSTS. ALREADY RUNNING 20-23 KTS IN PARTS OF OUR CWA. TODAY... A VIGOROUS SHORT WAVE DISTURBANCE...LAST ONE FOR THIS LONG WAVE TROUGH WAS LOCATED OVER NORTH BAY (CYYB) ONTARIO PROVINCE CANADA EARLY THIS MORNING. THIS SHORT WAVE WILL TRACK ACROSS NORTHERN NEW ENGLAND THIS AFTERNOON. GOOD SHEAR VORTICITY NOTED ACROSS THE NORTHERN ZONES FOR THIS AFTERNOON. COLDEST H5 TEMPS FROM -14 TO -16C ALSO LOCATED ACROSS SOUTHERN NEW HAMPSHIRE AND NORTHERN MASSACHUSETTS TODAY. BRIEF MARGINAL LOW LEVEL INSTABILITY AND AVAILABLE MOISTURE WILL BECOME CO-LOCATED WITH COLDEST H5 TEMPS LATE THIS MORNING AND EARLY THIS AFTERNOON AS THE SHORT WAVE APPROACHES. THEN DRIER AIR QUICKLY ARRIVES THIS AFTERNOON. OVERALL CONFINED CHANCE POPS WITH SLIGHT CHANCE OF THUNDERSTORMS ACROSS SOUTHERN NEW HAMPSHIRE AND NORTHEAST MASSACHUSETTS TODAY. GENERALLY MOST OF THE DAY WILL BE DRY AND IT WILL BECOME BREEZY. HIGH TEMPERATURES WILL BE APPROACHING SEASONAL NORMS...MID 70S ACROSS THE INTERIOR HIGH TERRAIN TO THE LOWER 80S ALONG THE COASTAL PLAIN. && .SHORT TERM /MIDNIGHT TONIGHT THROUGH SUNDAY NIGHT/... TONIGHT.... COOL AND DRY WESTERLY FLOW PREVAILS WITH CLEARING SKIES AND DIMINISHING WINDS BY MIDNIGHT. GENERALLY FOLLOWED MAVMOS GUIDANCE. SUNDAY... MOSTLY SUNNY AND DRY CONDITIONS EXPECTED WITH WEAK H5 RIDGING! SOUTHWESTERLY FLOW WILL HELP BOOST TEMPERATURES AROUND SEASONAL NORMS IN THE UPPER 70S TO LOWER 80S. && .LONG TERM /MONDAY THROUGH FRIDAY/... SLOW-MOVING SHORT WAVE TROUGH IS MODELED TO DROP SOUTHEASTWARD INTO THE NORTHEAST ON MONDAY AS WEAK SFC LOW PRESSURE MOVES WELL TO THE SOUTH OF NEW ENGLAND. COOLING MID LEVEL TEMPERATURES AND MARGINAL SFC MOISTURE MAY ALLOW FOR SOME SCT SHOWERS AND ISOLD TSTMS ACROSS THE NWRN ZONES MONDAY AFTERNOON AS WEAK INSTABILITY DEVELOPS. COULD SEE MOST IF NOT ALL THE CWA DRY HOWEVER. AS FAR AS TEMPS GO...KEPT TEMPS AT THE COAST COOLER THAN MOST MODEL GUIDANCE OFFERS DUE TO EXPECTED ONSHORE FLOW. TUESDAY...RELATIVELY COOL TEMPS ALOFT IN CYCLONIC FLOW ON TUE. MAY SEE SOME AFTERNOON STORMS WHERE POCKETS OF INSTABILITY DEVELOP. SMALL HAIL A POSSIBILITY. PLAYED DAYTIME MAX TEMPS A GOOD 10 DEGREES BELOW NORMAL SEASONAL LEVELS. MAY NEED TO RAISE POPS IN LATER FORECAST. NOT THINKING WASHOUT BY ANY MEANS...BUT THERE COULD BE A FAIR AMOUNT OF CONVECTIVE SHOWERS/STORMS AROUND. STINGY UPPER TROF HANGS AROUND ON WED. MAY HAVE TO GO WITH HIGHER POPS THAN CURRENTLY FORECAST...BUT DON/T WANT TO GO TOO OVERBOARD AT THIS TIME. TROF COULD BE A BIT MORE PROGRESSIVE...POSSIBLY OFFERING SUNNIER SKIES AND WARMER TEMPS. WE NOTE THAT 12Z ECMWF IS RATHER WET HOWEVER. MODELS AGREE THAT WARMER WEATHER COULD BE IN THE CARDS FOR THE END OF THE WEEK INTO THE WEEKEND...HOWEVER...NO CONFIDENT AT ALL ON ANYTHING HOT. GFS IS PROBABLY TOO FAST WITH COLD FRONT LATE IN THE WEEK...PREFER ECMWF TIMING OVER THE WEEKEND. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... TODAY...VFR. SCT SHRA/WDLY SCT TSRA MHT GENERALLY FROM NOW TO 1930Z. W SFC WINDS G25 KT 18Z-00Z. TONIGHT AND SUNDAY...VFR. OUTLOOK /MONDAY THROUGH THURSDAY/... GENERALLY VFR BUT WITH SCATTERED MVFR CIGS/VSBYS IN SHOWERS ESPECIALLY TUESDAY AFTN ...AND POSSIBLY AGAIN WED AFTN. EARLY MORNING FOG MAY LIMIT VSBYS AT TIMES...ESPECIALLY AT THE IMMEDIATE COAST AND ACROSS THE FAR INTERIOR. && .MARINE... TODAY AND TONIGHT...SFC WIND GUSTS 25-30 KT NEAR SHORE THIS AFTERNOON E MA COAST AND SCA HAS BEEN ISSUED ARD 915 AM FOR BOS HARBOR AND THE NR SHORE WATERS PYM-NBT. MAX GUSTS SHOULD OCCUR 3PM-6PM TODAY. WILL SEE SW WINDS 15-20 KT ACROSS THE OPEN WATERS. LOW LEVEL 1000-850MB LAPSE RATES DO NOT SUPPORT SUFFICIENT MIXING ACROSS THE OPEN WATERS UNTIL LATE THIS AFTERNOON AND EARLY EVENING AS DRIER DEWPOINT AIR FINALLY ADVECTS ACROSS MOST OF THE WATERS BEHIND A COLD FRONT. SMALL CRAFT ADVISORY BETWEEN 20Z AND 08Z THIS AFTERNOON THROUGH TONIGHT ACROSS THE SE OUTER WATERS. INCREASING SW FETCH COULD BRING 5 FT SEAS ACROSS THE SE OUTER WATERS AT THAT TIME. SUNDAY...SW WIND GUSTS TO 20 KT NEAR SHORE. OTHERWISE WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. OUTLOOK /MONDAY THROUGH THURSDAY/... WINDS AND SEAS LOOK TO REMAIN BELOW SMALL CRAFT LEVELS THROUGH THE PERIOD. HOWEVER...THERE MAY BE TIMES WHERE THUNDERSTORMS PROVIDE FOR BRIEF PERIODS OF HIGHER WINDS AND SEAS...ESPECIALLY NEARSHORE...PERHAPS TUE AND WED. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ230- 250. SMALL CRAFT ADVISORY UNTIL 5 AM EDT SUNDAY FOR ANZ254-255. && $$ SYNOPSIS...WTB/STRAUSS NEAR TERM...DRAG/STRAUSS SHORT TERM...STRAUSS LONG TERM...EKSTER AVIATION...DRAG/EKSTER/STRAUSS MARINE...DRAG/EKSTER/STRAUSS