000 FXUS61 KBOX 041547 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1147 AM EDT SAT JUL 4 2009 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION THIS AFTERNOON 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 FOR THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 10 PM THIS EVENING/... 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 /10 PM THIS EVENING THROUGH 6 PM SUNDAY/... 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 /SUNDAY NIGHT THROUGH FRIDAY/... SUNDAY NIGHT MODEL CROSS SECTIONS SHOW GENERALLY DRY AIR ALTHOUGH WITH A LAYER OF 60-70 PCT RH AROUND 850 MB. EXPECT FAIR WEATHER WITH LIGHT WINDS. DEWPOINTS UPSTREAM ARE IN THE 50S...SO THIS SHOULD WELL REPRESENT OUR MINS SUNDAY NIGHT. NORMAL WARM SPOTS SUCH AS THE LARGER CITIES MAY LINGER AROUND 60. MONDAY SURFACE LOW PRESSURE PASSES WELL SOUTH OF NEW ENGLAND. WEAK HIGH PRESSURE OVER THE REGION TO START THE DAY WITH SOLAR HEATING AND FULL MIXING. THE WEAK PRESSURE GRADIENT WILL ALLOW LOCAL SEA BREEZES TO DEVELOP. MIXING LAYER TEMPS WILL WORK OFF OF 11-12C...SO MAX TEMPS SHOULD REACH AROUND 80...COOLER IN THE HIGHLANDS AND COAST. UPPER LOW PRESSURE SWINGS ACROSS WITH COLD POOL ALOFT. 500 MB TEMPS FORECAST TO AROUND -16C. AFTERNOON CUMULUS IS EXPECTED WITH THE STRONGEST GROWTH IN OUR NORTHERN AND WESTERN AREAS. MODEL CAPES REACH 1000 J/KG WITH PATCHES OF 1500 J...TOTAL TOTALS 50-55 AND WET BULB ZERO 8500-9000 FT. LOOKS LIKE SCATTERED MID TO LATE AFTERNOON TSTMS WITH HAIL POTENTIAL. TUESDAY-WEDNESDAY UPPER TROF AND COLD POOL REMAIN IN PLACE BUT WITH SLIGHTLY COOLER SURFACE MAX TEMPS. BEST INSTABILITY AND CLOUD GROWTH SHOULD BE IN OUR NORTHERN AREAS...UNDER THE COLDER TEMPS ALOFT. WE WILL GO WITH DIURNAL CLOUD CYCLE EACH DAY. BASED ON 00Z GLOBAL AND 00Z ECMWF WE WILL GO WITH MORE CLOUDS THAN MOS INDICATES ON WEDNESDAY. FOR POPS WE WILL GO WITH CHANCE NORTH AND SLGT CHANCE EXTREME SOUTH TUESDAY...AND 5-10 PCT LOWER WEDNESDAY. THURSDAY-FRIDAY PER THE MODELS...HIGH PRESSURE BUILDS IN THURSDAY WITH THE RIDGE AXIS MOVING OFFSHORE FRIDAY. IF THIS ACTUALLY OCCURS THEN IT WILL BRING QUITE A CHANGE IN OUR WEATHER. FOR NOW WE WILL GO WITH CLEAR OR MOSTLY CLEAR SKIES AND NO POPS. TEMPS MIX FROM 12C THURSDAY WHICH WOULD SUPPORT LOWER 80S...MAYBE MID 80S IN THE WARMEST SPOTS. WITH THE RIDGE AXIS EAST AND WARM ADVECTION IN PLACE OVER US...TEMPS WOULD MIX FROM APPROX 16C WHICH WOULD SUPPORT MID TO UPPER 80S. && .AVIATION /16Z SATURDAY THROUGH WEDNESDAY/... TODAY...VFR. SCT SHRA/WDLY SCT TSRA BOS-MHT GENERALLY FROM 17Z-18Z. W SFC WINDS G25 KT 18Z-00Z. TONIGHT AND SUNDAY...VFR. OUTLOOK /SUNDAY NIGHT THROUGH WEDNESDAY/... GENERALLY VFR BUT WITH SCATTERED MVFR CIGS/VSBYS IN SHOWERS ESPECIALLY MONDAY-TUESDAY-WEDNESDAY AFTERNOONS. ALSO AREAS OF IFR/LIFR IN EARLY MORNING FOG. && .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 /SUNDAY NIGHT THROUGH WEDNESDAY/... WINDS AND SEAS REMAIN BELOW SMALL CRAFT LEVELS THROUGH THE PERIOD. && .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 FROM 4 PM THIS AFTERNOON TO 5 AM EDT SUNDAY FOR ANZ254-255. && $$ SYNOPSIS...WTB/STRAUSS NEAR TERM...DRAG/STRAUSS 1146A SHORT TERM...STRAUSS LONG TERM...WTB AVIATION...WTB/DRAG/STRAUSS 1146A MARINE...WTB/DRAG/STRAUSS 1146A