376 FXUS61 KBOX 102250 AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 650 PM EDT SUN MAR 10 2013 .SYNOPSIS... DRY CONDITIONS AND MODERATING TEMPS EXPECTED THROUGH MON. THEN AN APPROACHING COLD FRONT WILL BRING WIDESPREAD WIND SWEPT SHOWERS TO THE REGION ON TUESDAY WITH LOCALLY HEAVY RAINFALL LIKELY. BEHIND THE FRONT...MAINLY DRY BUT CHILLY WEATHER FOLLOWS FOR THE REMAINDER OF THE WEEK AND INTO NEXT WEEKEND. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 7 PM UPDATE... BULK OF THE FORECAST REMAINS ON TAP FOR TONIGHT. HAVE ADJUSTED THE NEAR TERM SLIGHTLY TO REFLECT ONGOING CONDITIONS. ONLY MAJOR CHANGE WAS TO INSERT PATCHY FOG INTO THE FORECAST. BELIEVE MOISTURE WILL GET TRAP OVERNIGHT LEADING TO PATCHY GROUND FOG. USING THE UPS METHOD FOR FOG DEVELOPMENT...AKA THE CROSSOVER METHOD...HAVE A LITTLE MORE CONFIDENCE THEN LAST NIGHT TO INSERT THE FOG INTO THE FORECAST. TEMPS WILL DROP QUICKLY AFTER DARK BUT BECOME STEADY AFTERWARDS AS UPPER LEVEL CLD DECK WILL KEEP TEMPS FROM FULLY RADIATING OUT. PREVIOUS DISCUSSION... TONIGHT...BOTH THE SURFACE HIGH AND THE UPPER RIDGE MOVE OFFSHORE...ALLOWING A GREATER INFLUENCE FROM THE LOW PRESSURE SYSTEM IN THE GREAT LAKES. THIS WILL RESULT IN INCREASING MID TO HIGH CLOUDS OVERNIGHT. CLOUD COVER...WHILE HIGH...WILL CONTRIBUTE TO INSULATION...KEEPING OVERNIGHT TEMPERATURES A BIT WARMER THAN LAST NIGHT. ONCE AGAIN...WITH THE SNOW PACK...CLEAR SKIES...AND DEWPOINTS IN THE MID TO UPPER 20S...EXPECT FOG TO BE A POSSIBILITY AGAIN TONIGHT. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... MONDAY...EXPECT A MORE SOUTHERLY FLOW MONDAY WITH WARM ADVECTION BRINGING IN WARMER TEMPS. THIS WILL RESULT IN TEMPERATURES CLIMBING INTO THE LOW 50S MOST LOCATIONS. COOLER TEMPERATURES CAN BE EXPECTED IN AREAS WITH DEEPER SNOWPACK. WINDS INCREASE AT 925MB...WITH ENOUGH MIXING...COULD SEE SOME WIND GUSTS AT THE SURFACE TO 15 TO 20 MPH. MONDAY NIGHT...CLOUDS WILL BUILD IN AND THICKEN AHEAD OF THE NEXT LOW PRESSURE SYSTEM. IN ADDITION...RAIN SHOWERS MAY REACH THE WESTERN ZONES BY 12Z. WENT WITH A NON DIURNAL TEMPERATURE TREND OVERNIGHT AS SOUTHERLY WINDS BRING IN WARMER...MORE MOIST AIR. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE MID TO UPPER 30S WITH THE LOWEST TEMPERATURES BEFORE MIDNIGHT. && .LONG TERM /TUESDAY THROUGH SUNDAY/... HIGHLIGHTS... * MILD TEMPS BUT WIDESPREAD RAIN SHOWERS ON TUESDAY INTO TUES NIGHT. * BELOW NORMAL TEMPS FOR THE REST OF THE WEEK. CONFIDENCE LEVEL/MODEL GUIDANCE... HIGH CONFIDENCE IN OVERALL FORECAST...MODERATE CONFIDENCE ON TIMING. 12Z MODEL GUIDANCE IS IN OVERALL AGREEMENT SYNOPTICALLY WITH JUST A FEW DIFFERENCE IN THE MESOSCALE. HIGH CONFIDENCE BROAD UPPER LEVEL TROUGH PUSHING ACROSS THE EASTERN HALF OF THE CONUS. THIS TROUGH WILL BRING A WIDESPREAD RAIN SHOWERS TO SNE TUES INTO TUES NIGHT. HAVE HIGH CONFIDENCE THAT THE REGION WILL SEE PRECIP...MODERATE CONFIDENCE ON EXACT START AND END TIME. THIS TROUGH/UPPER LEVEL LOW WILL STAY PUT OVER SNE FOR QUITE SOMETIME PERHAPS INTO NEXT WEEK. THEREFORE HAVE HIGH CONFIDENCE IN BELOW AVERAGE TEMPS. OVERALL USED A BLEND OF GFS/HPC/EC AS THE MODELS SEEMS COMPARABLE TO EACH OTHER. DETAILS... TUESDAY... UPPER LEVEL TROUGH WILL PUSH A STRONG COLD FRONT ACROSS SNE BY BEGINNING ON TUESDAY LASTING INTO THE OVERNIGHT HOURS. EXPECT GOOD WAA AHEAD OF THE FRONT PUSHING 850MB TEMPS INTO THE 4C-6C. THIS WILL HELP AID IN SURFACE TEMPS INTO THE MID 50S. CAVEAT TO THE NICE WARM UP WILL BE THE GUSTY WINDS. MODELS SHOW A GOOD SOUTHERLY 50KT JET CORE AT 925 MB MOVING AHEAD OF THE FRONT WHICH WILL HELP AID IN THE GUSTY WINDS...PERHAPS 20-30 MPH AT THE SURFACE. THIS JET WILL ALSO HELP INCREASE THE MOISTURE ACROSS THE AREA FROM THE ATLANTIC. WITH SUCH A MOIST ATMOSPHERE COMBINED WITH GOOD JET DYNAMICS...HAVE HIGH CONFIDENCE THAT WIDESPREAD RAIN WILL OCCUR. PWAT VALUES ARE APPROX AN INCH ACROSS THE AREA...SO BELIEVE THAT PERHAPS AN INCH OF PRECIP WILL FALL. HOWEVER HAVE NOTICED THAT NCEP MODELS ARE TRYING TO GIVE US OVER 2 INCHES OF QPF. UNCERTAIN IF THAT IS REASONABLE OR NOT...BUT FOR NOW FEEL CONFIDENCE WITH AROUND AN INCH OF QPF...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. THIS MAY LEAD TO URBAN AND POOR DRAINAGE FLOODING...ALONG WITH STEADY RISES IN SOME OF THE SMALL AND MAIN STREAM RIVERS. MORE INFO/THOUGHTS BELOW IN THE HYRO SECTION. EXPECT PRECIP TO QUICKLY DIMINISH FROM WEST TO EAST OVERNIGHT TUESDAY INTO WEDNESDAY MORNING. WEDNESDAY THOUGH SATURDAY... UPPER LEVEL DISTURBANCE WILL PUSH THROUGH SNE PUSHING THE SURFACE LOW OFFSHORE TOWARDS THE MARITIMES. THIS WILL ALLOW FOR DRY AIR TO QUICKLY MOVE IN AND DROP DEWPOINTS. ALSO WINDS FROM THE SOUTH WILL SWITCH TO THE NW AND CAA WILL START TO FILTER IN. WED TEMPS WILL BE CLOSER TO AVG FOR THIS TIME OF YEAR BUT WITH THE BRISK NW WINDS...IT WILL FEEL A LOT CHILLIER. UPPER LEVEL LOW WILL GET CUT OFF AND ROTATE ACROSS NORTHERN NEW ENGLAND...KEEPING THE NW FLOW ACROSS THE REGION. DUE TO COLD POOL ALOFT AND SEVERAL SHORTWAVE ROTATING AROUND THE LOW...EXPECT CLOUDS OR EVEN A FEW ISOLATED SNOW/RAIN SHOWERS FOR THE END OF THE WEEK. TEMPERATURES WILL REMAIN BELOW AVG FOR THIS TIME FRAME...UPPER TO MID 30S FOR HIGHS WITH UPPER TEENS TO MID 20S FOR LOWS. PATTERN DOESNT LOOK TO BREAK UNTIL SOMETIME NEXT WEEK...JUST WAITING FOR A SYSTEM TO PUSH THE LOW OUT OF THE REGION. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT. MODERATE...30 TO 60 PERCENT. HIGH...GREATER THAN 60 PERCENT. TONIGHT...HIGH CONFIDENCE. VFR MOST LOCATIONS. LOW PROBABILITY OF MVFR FOG IN VALLEY LOCATIONS. MODELS TRY TO PRODUCE LOW MVFR/IFR CIGS AREA WIDE...BELIEVE THAT ITS OVERDONE WITH THE MOISTURE. MONDAY...HIGH CONFIDENCE. MAINLY VFR. MODERATE PROBABILITY OF MVFR CIGS ON THE SOUTH COAST WITH ONSHORE FLOW. MONDAY NIGHT...HIGH CONFIDENCE ON TRENDS...MODERATE CONFIDENCE ON TIMING. MVFR/IFR CIGS DEVELOPING FROM WEST TO EAST AFTER 04Z. RAIN SHOWERS OCCURRING FROM WEST TO EAST AFTER 09Z. KBOS TAF...HIGH CONFIDENCE ON TRENDS. MODERATE CONFIDENCE ON TIMING. EXPECT MAINLY VFR OVERNIGHT WITH LOW PROB OF MVFR CIGS. WINDS WILL BE LIGHT AND VARIABLE OVERNIGHT. KBDL TAF...HIGH CONFIDENCE VFR. LOW PROBABILITY OF MVFR FOG OVERNIGHT. OUTLOOK...TUESDAY THROUGH FRIDAY... TUESDAY INTO EARLY WED...MODERATE CONFIDENCE. CONDITIONS DETERIORATING TO IFR WITH AREAS OF LIFR POSSIBLE FOR MOST OF TUESDAY IN HEAVY SHOWERS AND AREAS OF FOG. GUSTY WINDS AS WELL UP TO 35KTS POSSIBLE. CONDITIONS SHOULD RAPIDLY IMPROVE TO VFR FROM WEST TO EAST LATE TUESDAY NIGHT INTO WEDNESDAY. WED THROUGH FRIDAY. MODERATE CONFIDENCE. VFR AND DRY WEATHER LIKELY BUT CAN/T RULE OUT MARGINAL MVFR-VFR CIGS DURING THE AFTN AND EARLY EVENING. LOW PROB OF ISOLATED RAIN/SNOW SHOWER. && .MARINE... HIGH CONFIDENCE. SMALL CRAFT ADVISORIES FOR HAZARDOUS SEAS CONTINUE THROUGH MONDAY NIGHT. SEAS OF 10 TO 15 FEET INITIALLY OVER THE OUTER WATERS GRADUALLY DIMINISHING TO 5 TO 8 FEET INTO MONDAY NIGHT. WINDS SHIFT TO THE SOUTHEAST THIS EVENING BUT WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS. OUTLOOK...TUESDAY THROUGH FRIDAY... MODERATE CONFIDENCE IN FORECAST. STRONG COLD FRONT WITH SHOWERS AND GUSTY WINDS WILL IMPACT THE WATERS TUESDAY INTO EARLY WED MORNING. EXPECT LOW VSBYS...SEAS 7-10 FT...AND STRONG SOUTHERLY WINDS...NEAR GALES. WINDS WILL SWITCH TO THE NW ON WED AND CONTINUE THROUGH THE REST OF THE WEEK. EXPECT SCA CONDITIONS THROUGH FRIDAY...ESP FOR THE SOUTHERN WATERS. && .HYDROLOGY... A STRONG COLD FRONT WILL IMPACT THE AREA ON TUESDAY LASTING INTO TUESDAY NIGHT. THIS FRONT IS EXPECTED TO BRING WIDESPREAD PRECIP AS WELL AS SOME LOCALLY HEAVIER SHOWERS ALONG THE FRONT. EVEN THOUGH NCEP MODELS ARE TYING TO PRODUCE 2.5 INCHES OF QPF...BELIEVE AMOUNTS WILL BE A LITTLE LESS PER THE EC. MAIN QUESTION HOWEVER IS WHERE THE AXIS OF PRECIP WILL FALL. RIGHT NOW BELIEVE THE HEAVIER AXIS WILL FALL ACROSS THE CT VALLEY...PRODUCING NEAR AN INCH OF QPF. HOWEVER THE AXIS OF HEAVIER PRECIP COULD BE ACROSS THE BERKSHIRES...OR ACROSS EASTERN MASS. WITH THE GRADUAL SNOW MELT OVER THIS WEEKEND COMBINED WITH HEAVY RAINFALL...EXPECT SOME URBAN AND POOR DRAINAGE FLOODING ACROSS THE MORE VULNERABLE AREAS. IF 1.5 INCHES OR PRECIP FALLS OVER THE EASTERN HALF OF THE AREA...WE COULD EVEN SEES SOME FLOODING IN THE MAIN STREAM RIVERS. MOST OF THE FORECAST POINTS WILL REACH INTO ACTION STAGE PER HELP FROM THE NERFC. HOWEVER WE WILL HAVE TO KEEP AN EYE OUT FOR THE MORE SUSCEPTIBLE RIVERS INCLUDING THE CHARLES RIVER AT DOVER...THE PAWTUXET AT CRANSTON...AND THE ASSABET RIVER AT MAYNARD. RIGHT NOW THE FEELING IS THAT SOME OF THESE RIVER MAY JUST HIT ACTION STAGE...BUT WE WILL HAVE TO WATCH CLOSELY AND SEE HOW MUCH QPF FALLS WITHIN THEIR BASINS. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT MONDAY FOR ANZ231-232. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 AM EDT TUESDAY FOR ANZ235-237-250-251-254>256. && $$ SYNOPSIS...DUNTEN/RLG NEAR TERM...DUNTEN/RLG SHORT TERM...RLG LONG TERM...DUNTEN AVIATION...DUNTEN/RLG MARINE...DUNTEN/RLG HYDROLOGY...DUNTEN