AFDBOX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 745 AM EDT MON APR 18 2011 .SYNOPSIS... HIGH PRESSURE WILL BRING DRY...SEASONABLE CONDITIONS THROUGH THIS AFTERNOON. UNSETTLED WEATHER WILL RETURN TONIGHT THROUGH WEDNESDAY...BRINGING PERIODS OF CLOUDS AND SHOWERS. A COLD FRONT WILL SWING THROUGH WEDNESDAY NIGHT. HIGH PRESSURE WILL BRING DRY BUT COOL CONDITIONS FROM THURSDAY THROUGH FRIDAY NIGHT. MORE UNSETTLED WEATHER IS FORECAST TO MOVE IN NEXT WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... SKIES HAVE DAWNED MAINLY SUNNY THIS MORNING...EXCEPT FOR A FEW CLOUDS ALONG THE S COAST AND ACROSS THE CT VALLEY INTO S NH. EXPECT PARTLY TO MOSTLY SUNNY SKIES INTO EARLY THIS AFTERNOON. HIGH TEMPERATURES SHOULD BE RATHER SEASONABLE FOR THIS TIME OF YEAR...GENERALLY BETWEEN 55 AND 60. IT WILL FEEL A TAD COOLER AS BUFKIT SHOWING GUSTY WEST TO SOUTHWEST WINDS DEVELOPING OF 25 TO 30 MPH AT TIMES. WE SHOULD SEE SKIES BECOME MOSTLY CLOUDY FROM WEST TO EAST DURING THE MID TO LATE AFTERNOON HOURS. A FEW SPOT SHOWERS MAY POP UP TOWARDS 00Z TUESDAY TO THE NORTHWEST OF A BOSTON TO PROVIDENCE LINE...SO INCLUDED A 20 TO 30 POP TOWARDS THIS TIME ACROSS THAT AREA. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... TONIGHT... A WEAK COLD FRONT WILL SLOWLY PUSH SOUTH AND PROBABLY BE LOCATED NEAR THE SOUTH COAST BY 12Z TUESDAY. A WEAK WAVE OF LOW PRESSURE WILL RIDE ALONG THE FRONT AND PROBABLY BRING A FEW SHOWERS. CERTAINLY NOT EXPECTING A WASHOUT AND MUCH OF THE TIME SHOULD BE DRY IN A GIVEN LOCATION. THEREFORE...WILL CARRY JUST CHANCE POPS. AS FOR LOW TEMPERATURES...SIDED WITH THE WARMER GUIDANCE WITH A FAIR AMOUNT OF CLOUDS AROUND THE REGION. LOWS SHOULD MAINLY BE IN THE LOWER TO MIDDLE 40S WITH A FEW UPPER 30S POSSIBLE IN SOUTHWEST NH/NORTHWEST MA. TUESDAY... A SECOND WAVE OF LOW PRESSURE WILL BE RIDING ALONG THE FRONT WHICH SHOULD BE TO THE SOUTH OF OUR REGION. THIS WILL RESULT IN A MAINLY CLOUDY DAY AND ALSO THE THREAT FOR SHOWERS AT TIMES. APPEARS TO BE SOMEWHAT BETTER FORCING WITH THIS SECOND WAVE SO WILL GO WITH SOME LIKELY POPS. HOWEVER...WERE NOT EXPECTING A HEAVY RAIN EVENT FROM THIS SYSTEM. WITH THE FRONT MAINLY TO THE SOUTH OF OUR REGION AND AN ABUNDANCE OF CLOUDS...THINK TEMPERATURES WILL BE A BIT COOLER THAN TODAY. HIGHS SHOULD MAINLY BE BETWEEN 50 AND 55...BUT SOME COASTAL LOCATIONS MAY HOLD IN THE UPPER 40S WITH AN ONSHORE FLOW. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... MEDIUM RANGE MODELS ARE IN PRETTY GOOD AGREEMENT WITH THEIR UPPER LEVEL PATTERN...WHICH FEATURES A PROGRESSIVE...BROAD ZONAL FLOW ACROSS THE LOWER 48 THROUGH THIS TIMEFRAME. WITH THE FAST FLOW ALOFT...OP MODELS ARE HANDLING MOVEMENT OF SURFACE SYSTEMS DIFFERENTLY...SO USED A BLEND OF THE 00Z GFS...12Z ECMWF AND THEIR ENSEMBLES...WHICH HELPED BRING THINGS INTO A BIT SOMEWHAT BETTER FOCUS FOR TIMING. TUESDAY NIGHT-WEDNESDAY...FRONTAL BOUNDARY STALLED S OF NEW ENGLAND WILL TO MOVE CLOSER TO THE REGION AS A WEAK WAVE OF LOW PRES MOVES ALONG IT TUESDAY NIGHT. THIS WILL BRING LOW LEVEL MOISTURE WITH SHOWERS AND FOG. IN THE MEANTIME...ANOTHER STRONGER H500 SHORTWAVE WITH AN ASSOCIATED SURFACE LOW WILL MOVE THROUGH THE OHIO VALLEY TUESDAY NIGHT. THIS WILL SEND MORE MOISTURE ALONG THE STALLED FRONT...EVENTUALLY HELPING IT MOVE BACK N AS A WARM FRONT DURING WEDNESDAY. AS THIS LOW MOVES NE...WINDS WILL SHIFT TO S-SW DURING WEDNESDAY. GOOD INSTABILITY ALSO HEADS IN AS THE LOW/S ASSOCIATED COLD FRONT STARTS TO APPROACH. K INDICES WILL INCREASE TO THE LOWER 30S...TOTAL TOTALS INTO THE LOWER 50S AND SHOWALTER INDICES BELOW ZERO WEDNESDAY AFTERNOON. SO...HAVE ALSO MENTIONED ISOLATED THUNDERSTORMS FOR MANY LOCATIONS. HAVE BROUGHT IN LIKELY POPS AS WELL. THERE IS STILL SOME QUESTION AS TO HOW FAR N THE WARM FRONT WILL MOVE ON WEDNESDAY...AND POSSIBLY HAVING A DRY SLOT WORK IN PRIOR TO THE APPROACH OF THE COLD FRONT WEDNESDAY AFTERNOON. FOR NOW...KEEP THE FRONT NOT TOO FAR TO THE N OF THE REGION WITH DAYTIME HIGHS ONLY IN THE 50S AS CLOUDS AND SHOWERS LINGER. HOWEVER...IF WHAT THE NEW 00Z OP ECMWF IS CLOSE...TEMPS MAY GO EVEN HIGHER WITH SOME BREAKS OF SUNSHINE. THIS WILL ALSO HELP INCREASE THE INSTABILITY FOR CONVECTION LATER IN THE DAY. WEDNESDAY NIGHT...HAVE CONTINUED TO CARRY LIKELY POPS FOR MOST OF THE REGION THROUGH AROUND MIDNIGHT AS THE COLD FRONT PASSES THROUGH. ALSO CONTINUED TO MENTION SCATTERED THUNDERSTORMS AHEAD OF THE FRONT. LOOKS LIKE THE FRONT SHOULD BE OFFSHORE BY AROUND 06Z OR SO. CLEARING BEHIND THE FRONT MAY WORK IN QUICKER THAN CURRENT THINKING...BUT STILL NOTING THE UPPER LEVEL TROUGH WORKING THROUGH INTO THURSDAY SO KEPT MENTION OF SHOWERS THROUGH THE NIGHT. THURSDAY...WITH THE UPPER TROUGH WORKING THROUGH THE REGION THROUGH MIDDAY...EXPECT LEFTOVER SCATTERED SHOWERS ACROSS MOST AREAS ESPECIALLY OVER S NH/E AND CENTRAL MA. WILL THEN SEE CLEARING BUT BRISK CONDITIONS WITH WEST WINDS GUSTING UP TO 25-30 MPH ESPECIALLY ACROSS THE HIGHER TERRAIN AND ALONG THE COAST. HIGH PRES WILL WORK INTO NORTHERN AREAS THURSDAY NIGHT...WITH MOSTLY CLEAR AND CHILLY CONDITIONS. FRIDAY...HIGH PRES WILL BUILD OVERHEAD WITH MOSTLY SUNNY SKIES. EXPECT TEMPS TO RUN UP TO 5 DEGREES BELOW SEASONAL NORMALS FOR THIS TIME OF YEAR. HIGH CLOUDS MAY START TO WORK INTO WESTERN AREAS DURING THE AFTERNOON...WHICH WILL INCREASE AND THICKEN DURING FRIDAY NIGHT. NEXT SYSTEM STARTS TO APPROACH AFTER MIDNIGHT. HAVE MENTIONED CHANCE POPS INTO THE CT VALLEY AFTER MIDNIGHT. SATURDAY-SUNDAY...ANOTHER LOW MOVES OUT OF THE CENTRAL MISSISSIPPI RIVER VALLEY INTO THE GREAT LAKES. LOOKS LIKE THIS LOW WILL BRING ANOTHER WARM FRONT TO THE REGION DURING SATURDAY WITH ANOTHER THREAT OF SHOWERS. TIMING IS STILL IN QUESTION WITH PUSHING THIS LOW/S ASSOCIATED COLD FRONT THROUGH...BUT CURRENT THINKING IS FOR SOMETIME SUNDAY...POSSIBLY EARLY. CONTINUED LOW CONFIDENCE WITH THIS PORTION OF THE FORECAST. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... FORECASTER CONFIDENCE LEVELS... LOW...LESS THAN 30 PERCENT MEDIUM...30 PERCENT TO 60 PERCENT HIGH...GREATER THAN 60 PERCENT TODAY...HIGH CONFIDENCE IN VFR CONDITIONS. EXPECT WEST TO SOUTHWEST WIND GUSTS OF 20 TO 25 KNOTS. TONIGHT...MEDIUM CONFIDENCE. DESPITE AN ABUNDANCE OF MID LEVEL CLOUDINESS AND A FEW SHOWERS...VFR CONDITIONS WILL PROBABLY BE DOMINANT. HOWEVER...SOME MARGINAL MVFR CEILINGS AND VISIBILITIES MAY OCCUR AT TIMES MAINLY AFTER MIDNIGHT. TUESDAY...MEDIUM CONFIDENCE. VFR TO BORDERLINE MVFR BROKEN TO OVERCAST CEILINGS EXPECTED. THE BETTER CHANCE OF MVFR CONDITIONS WILL OCCUR IN THE AFTERNOON ALONG WITH SOME SHOWERS. KBOS TERMINAL...HIGH CONFIDENCE IN VFR TODAY. MEDIUM CONFIDENCE IN TAF TONIGHT AND TUESDAY. EXPECT VFR CONDITIONS TO DOMINATE TONIGHT AND TUESDAY...BUT A PERIOD OR TWO OF MVFR CEILINGS ARE POSSIBLE WITH THE BEST CHANCE ON TUESDAY. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUESDAY NIGHT-WEDNESDAY NIGHT...LOW TO MEDIUM CONFIDENCE. MVFR CIGS/VSBYS LIKELY...WITH PERIODS OF IFR CIGS/VSBYS IN SHOWERS AND FOG. MAY SEE ISOLD TO SCATTERED THUNDERSTORMS WEDNESDAY AFTERNOON AND EARLY WEDNESDAY NIGHT. E WINDS ON TUESDAY NIGHT WILL SHIFT TO S-SE WEDNESDAY THEN SW ON WEDNESDAY NIGHT. MAY SEE SOME GUSTS UP TO 20-25 KT DURING WEDNESDAY INTO WEDNESDAY NIGHT. THURSDAY...MEDIUM CONFIDENCE. LEFTOVER MVFR CIGS/VSBYS THURSDAY MORNING ACROSS S NH/E MA...OTHERWISE CONDITIONS SHOULD BE VFR. W WINDS WILL GUST TO 30-35 KT MAINLY OVER THE HIGHER TERRAIN AND ALONG THE COAST DURING THE DAY...THEN DIMINISHING THU NIGHT. FRIDAY...MEDIUM CONFIDENCE FOR VFR CONDITIONS. && .MARINE... TODAY...SCA HEADLINES REMAIN POSTED FOR ALL WATERS AS BUFKIT SHOWS GOOD MIXING. THIS SHOULD YIELD WEST TO SOUTHWEST WIND GUSTS OF 25 KNOTS. TONIGHT...WINDS SHOULD DIMINISH BELOW SCA THRESHOLDS BY EARLY EVENING. HOWEVER...WILL NEED TO CONTINUE SCA FOR SEAS FOR ALL OF TONIGHT AS SEAS WILL REMAIN AT OR ABOVE 5 FEET IN THIS REGION. TUESDAY...WINDS SHOULD REMAIN BELOW SCA THRESHOLDS AS COLD FRONT PUSHES SOUTH OF MOST OF THE WATERS. HOWEVER...NORTH TO NORTHEAST WIND GUSTS UP TO 20 KNOTS ARE EXPECTED. SEAS WILL REMAIN AROUND 5 FEET ACROSS THE SOUTHERN OUTER-WATERS SO SCA HEADLINES MAY NEED TO BE EXTENDED. OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY... TUESDAY NIGHT-WEDNESDAY...EXPECT WINDS TO REMAIN BELOW SMALL CRAFT CRITERIA FOR THIS PERIOD. HOWEVER...SEAS WILL REMAIN AT OR ABOVE 5 FT ON THE SOUTHERN WATERS...WHILE INCREASING ON THE EASTERN WATERS TO SMALL CRAFT LEVELS BY WEDNESDAY WITH THE CONTINUED ONSHORE FLOW. ISOLATED TSTMS POSSIBLE WED AFTERNOON. WEDNESDAY NIGHT...WINDS AND SEAS WILL REMAIN ABOVE SMALL CRAFT CRITERIA. LOW PROBABILITY OF THUNDERSTORMS PRIOR TO WINDS SHIFTING FROM SW-W...MAINLY BEFORE MIDNIGHT. THURSDAY...WEST WINDS WILL GUST UP TO 30 KT. LOW PROBABILITY OF 35 KT GUSTS. SEAS WILL REMAIN AT OR ABOVE 5 FT OVER THE OPEN WATERS. FRIDAY...EXPECT WIND GUSTS AND SEAS UP TO SMALL CRAFT CRITERIA MAINLY ON THE EASTERN OUTER WATERS EARLY...THEN WILL DIMINISH. && .HYDROLOGY... THE HEAVY RAINFALL FROM THIS PAST WEEKEND ALONG WITH RECENT SNOWMELT FROM NORTHERN NEW ENGLAND HAS CONTINUED TO CAUSE RIVER RISES ALONG SOME OF THE MAINSTEM RIVERS AND TRIBUTARIES. MINOR FLOODING CONTINUES ALONG PORTIONS OF THE CONNECTICUT RIVER. A FLOOD WARNING CONTINUES FOR THE CONNECTICUT RIVER AT NORTHAMPTON...THOMPSONVILLE AND HARTFORD. THESE LOCATIONS ARE EXPECTED TO REMAIN IN MINOR FLOOD UNTIL FURTHER NOTICE. THE CONNECTICUT RIVER AT MIDDLETOWN MAY GO INTO LOW END MODERATE FLOODING THIS MORNING...SO WILL CONTINUE TO MONITOR CLOSELY. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...NONE. MA...NONE. NH...NONE. RI...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ230>234-236. SMALL CRAFT ADVISORY UNTIL 7 AM EDT TUESDAY FOR ANZ235-237- 254>256. SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR ANZ250. SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR ANZ251. && $$ SYNOPSIS...FRANK/EVT