000 FXUS61 KBOX 021412 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 1012 AM EDT FRI OCT 2 2009 .SYNOPSIS... WEAK HIGH PRESSURE WILL COVER SOUTHERN NEW ENGLAND THIS AFTERNOON. A FRONTAL SYSTEM BRINGS UNSETTLED WEATHER TONIGHT THROUGH EARLY SUNDAY. DRY BUT COOL WEATHER PREVAILS EARLY NEXT WEEK. ANOTHER LOW PRESSURE AREA MAY BRING MORE UNSETTLED WEATHER BY WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MINOR CHANGES TO TEMPS AND SKY COVER BUT WITH THE SAME OUTCOME THIS AFTERNOON. CLOUDS ARE WORKING IN THROUGH THE CATSKILLS AND WILL INCREASE ACROSS OUR AREA DURING THE AFTERNOON AND EVENING. RADAR SHOWS LIGHT SHOWERS OVER NORTHEAST PA MOVING EAST...BUT WITH THE UPPER FLOW TURNING DURING THE AFTERNOON THESE SHOULD LIFT NORTH AND REMAIN MAINLY WEST OF SOUTHERN NEW ENGLAND...POSSIBLY CLIPPING THE WESTERN HILLS. AMDAR SOUNDINGS SHOW APPROX 1C AT 850 MB WITH MIXING TO THAT VICINITY. THAT WOULD SUPPORT MAX TEMPS IN THE LOW 60S...THE CURRENT FORECAST ARRAY LOOKS CONSISTANT WITH THIS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... THE HIGH PRESSURE SYSTEM IS FORECAST TO INTENSIFY AS IT MOVES EAST OF GEORGES BANK TONIGHT INTO SATURDAY WITH STRONG LOW PRESSURE MOVING ACROSS THE GREAT LAKES. THE GRADIENT BETWEEN THESE TWO SYSTEMS WILL CAUSE AN INCREASINGLY MOIST SOUTHERLY AIR FLOW ACROSS OUR REGION. MISCELLANEOUS AREAS OF RAIN SHOWERS ARE LIKELY TO MOVE EAST AND/OR DEVELOP FRIDAY NIGHT. NON DIURNAL TEMPERATURE PATTERN IS FORECAST...WITH TEMPERATURES RISING THROUGH THE 50S TONIGHT. THE MAIN RAIN EVENT WILL OCCUR ON SATURDAY AS STRONG UPPER LEVEL DYNAMICS HEAD TOWARD SOUTHERN NEW ENGLAND. WE WILL BE IN THE RIGHT REAR QUADRANT OF A 105 KNOT JET MAX AT 300 MB. THIS REGION IS FAVORABLE FOR STRONG UPWARD MOTION. ALL MODELS SHOW A BAND OF SHOWERS AND THUNDERSTORMS MOVING SLOWLY ACROSS THE REGION. K INDICES REACH MID 30S WITH TOTAL TOTALS INDICES IN THE UPPER 40S. WINDS NEAR THE SURFACE WILL BE E TO SE AT AROUND 10 MPH INLAND...BUT WILL BE FROM THE SOUTH AT 35-45 MPH AT ONLY 2000 FT. THIS SPEED SHEAR...COUPLED WITH DEW POINT TEMPERATURES RISING INTO THE LOWER TO MID 60S...COULD LEAD TO A FEW STRONG THUNDERSTORMS...WITH LOCALLY HEAVY DOWNPOURS. THE STORM PREDICTION CENTER MENTIONS THAT THE DEEP LAYER WIND SHEAR MAY BE ENOUGH TO POSSIBLY SPAWN A TORNADO BUT THEY ACKNOWLEDGE THAT INSTABILITY MAY BE TOO MARGINAL FOR SEVERE WEATHER TO OCCUR. TOTAL RAINFALL MAY REACH 1 TO 2 INCHES AT SEVERAL LOCATIONS. RIGHT NOW...THIS SYSTEM IS RATHER PROGRESSIVE AND EXCESSIVE RAINFALL TOTALS ARE NOT ANTICIPATED. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... LONG RANGE MODELS AND ENSEMBLE GUIDANCE INDICATE FAIRLY GOOD AGREEMENT THROUGH MONDAY WITH THE OVERALL SYNOPTIC SCALE PATTERN...WITH MORE SPREAD APPROACHING DAYS 5 THROUGH 7 OR TUESDAY THROUGH THURSDAY OF NEXT WEEK. THE NAO GFS BASED ENSEMBLES INDICATE A POSITIVE PHASE DEVELOPING WHICH WOULD GENERALLY FAVOR AN INCREASINGLY PROGRESSIVE H5 FLOW ACROSS THE EASTERN CONUS. THE DAILIES... SATURDAY NIGHT THROUGH SUNDAY MORNING...A COLD FRONT WILL SWING ACROSS SOUTHERN NEW ENGLAND. A SOUTHERLY LOW LEVEL JET WILL PROVIDE LEFTOVER MOISTURE CONVERGENCE WITH LINGERING EVENING SHOWERS AND PERHAPS A THUNDERSTORM ACROSS EASTERN SECTIONS. MEANWHILE HYBRID LOW PRESSURE DEVELOPING NEAR THE BAHAMAS WILL TRACK NORTHEAST ACROSS THE OFFSHORE WATERS SE OF THE REGION AND EAST OF THE FRONT. IT NOW APPEARS ITS WRAP AROUND MOISTURE WILL BE DIRECTED ACROSS EXTREME EASTERN PORTIONS OF SOUTHERN NEW ENGLAND LATE SATURDAY NIGHT INTO SUNDAY MORNING. THE CAPE AND ISLANDS SHOULD EXPERIENCE LEFTOVER SHOWERS SUNDAY MORNING WITH MUCH OF THE REMAINDER OF THE AREA DRY AT THAT TIME. A THUNDERSTORM CANNOT BE RULED OUT...MAINLY EAST. SUNDAY AFTERNOON THROUGH MONDAY... AN INVERTED TROUGH WILL ALLOW FOR CLOUDS TO PERSIST INTO SUNDAY AFTERNOON ALONG THE EAST COAST. OTHERWISE THE UPPER LEVEL TROUGH SWINGS THROUGH THE REGION SUNDAY NIGHT...FOLLOWED BY COOLER AIR MONDAY. DUE TO CYCLONIC FLOW AND STEEPENING LAPSE RATES...CLOUDS WILL DOMINATE MONDAY MAINLY ACROSS THE INTERIOR. A FEW LIGHT SHOWERS OR SPRINKLES WILL BE POSSIBLE WITH THE COLD POOL OVER THE AREA. H5 TEMPS ADVERTISED TO DROP BETWEEN -17 AND -22 CELSIUS. GIVEN THE COLD AIR ADVECTION PATTERN...CLOUD COVER AND 1000-500MB THICKNESSES ALMOST 10 DM LOWER THAN SUNDAYS....TEMPERATURES MONDAY SHOULD BE A GOOD 5 TO 7 DEGREES COOLER THAN SUNDAYS HIGHS. TUESDAY THROUGH THURSDAY...NEXT FRONTAL SYSTEM WILL APPROACH BY LATE TUESDAY. GFS LOOKS TO BE A BIT FAST WITH THE TIMING...SO HELD OFF CHANCE POPS UNTIL THE TUESDAY NIGHT AND WEDNESDAY TIMEFRAME...MORE IN LINE WITH THE ECMWF. COOL AND DRIER WEATHER SHOULD BE IN STORE FOR THURSDAY. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... THIS AFTERNOON...VFR WITH INCREASING CLOUDS ABOVE 10 KFT. TONIGHT...VFR DETERIORATING TO MVFR CEILINGS IN THE 03Z-08Z TIME FRAME WITH RAIN SHOWERS SPREADING EASTWARD. ISOLATED IFR CONDITIONS POSSIBLE TOWARD DAYBREAK IN SHOWERS AND PATCHY FOG. INTRODUCED THE POSSIBILTY OF LOW LEVEL WIND SHEAR AT BDL AFTER 07Z WITH LIGHT SE WINDS INCREASING TO 40 KNOTS FROM THE SSE AT 2000 FT. THESE CONDITIONS WILL AFFECT ALL TERMINALS TOWARD DAYBREAK BUT THE TAFS DO NOT YET EXTEND THAT FAR OUT IN TIME. SATURDAY...IFR CONDITIONS IN SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL. SOUTHERLY LOW LEVEL WIND SHEAR CONTINUING...ESPECIALLY OVER EASTERN TERMINALS DURING THE MORNING. OUTLOOK /SATURDAY NIGHT THROUGH TUESDAY/... SATURDAY NIGHT THROUGH SUNDAY MORNING...IFR WITH LOW CEILINGS AND SHOWERS SHOULD IMPROVE TO MVFR THEN VFR ACROSS THE INTERIOR LATE SATURDAY NIGHT...EXCEPT SUNDAY MORNING ALONG THE COAST. SUNDAY AFTERNOON THROUGH MONDAY...SHIFTING WINDS BEHIND THE FRONT WITH VFR CONDITIONS PREVAILING. DIURNAL BROKEN STRATOCUMULUS PREVAILS MONDAY. TUESDAY...VFR. && .MARINE... QUIET WEATHER IN THE SHORT TERM THIS AFTERNOON AND THIS EVENING. SOUTHEAST WINDS WILL INCREASE OVERNIGHT AND SMALL CRAFT ADVISORIES HAVE BEEN POSTED FOR SOUTHERN PORTIONS OF THE WATERS LATE TONIGHT FOR WIND GUSTS APPROACHING 25 KTS AND SEAS NEARING 5 FT. SMALL CRAFT ADVISORIES ARE POSTED FOR ALL WATERS EXCEPT NARRAGANSETT BAY FOR SATURDAY. EXPECT SOUTH TO SOUTHEAST WINDS 15 TO 20 KTS WITH GUSTS TO 25 TO 30 KTS AT TIMES. SEAS MAY BUILD TO 5 TO 6 FT OVER THE OUTER WATERS AND RHODE ISLAND AND BLOCK ISLAND SOUNDS. OUTLOOK /SATURDAY NIGHT THROUGH TUESDAY/... SATURDAY NIGHT THROUGH SUNDAY MORNING...A SMALL CRAFT ADVISORY WILL PROBABLY CONTINUE DUE TO SOUTHEAST SWELL WITH SIGNIFICANT WAVE HEIGHTS OF 4 TO 7 FT ACROSS THE OPEN WATERS. SOUTHERLY WINDS WILL GUST UP TO 20 KT SAT EVENING. WIND MOMENTUM TRANSFER WILL BE LIMITED DUE TO A LOW LEVEL INVERSION. SUNDAY AFTERNOON THROUGH MONDAY...SCA CONTINUES. SHIFTING WINDS SUNDAY MIDDAY BEHIND THE COLD FRONT WITH LOW PRES OFFSHORE. WNW WINDS GUSTING TO 20 TO 25 KT BEHIND THE DEPARTING COLD FRONT MONDAY. SEAS SUBSIDING TO 3 TO 5 FT. TUESDAY...WINDS AND SEAS SHOULD DROP BELOW SCA CRITERIA AS WEAK HIGH PRES PREVAILS. && .CLIMATE... SEP 2009 MONTHLY CLIMATE SUMMARIES HAVE BEEN ISSUED FOR BOS...PVD...BDL AND ORH. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FROM 8 AM TO 6 PM EDT SATURDAY FOR ANZ230>234-250-251-254. SMALL CRAFT ADVISORY FROM 1 AM TO 6 PM EDT SATURDAY FOR ANZ235- 237-255-256. && $$ SYNOPSIS...STRAUSS/GAF NEAR TERM...WTB SHORT TERM...GAF LONG TERM...STRAUSS AVIATION...STRAUSS/GAF MARINE...STRAUSS/GAF CLIMATE...STRAUSS