Area Forecast Discussion
Issued by NWS Portland, ME

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KGYX 171546 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 1146 AM EDT FRI APR 17 2015 .SYNOPSIS... A WEAK COLD FRONT WILL CROSS THE REGION TODAY. LOW PRESSURE WILL APPROACH FROM THE NORTHWEST TONIGHT THEN CROSS THE AREA ON SATURDAY. HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST SATURDAY NIGHT AND SUNDAY. A WARM FRONT WILL APPROACH FROM THE SOUTH ON MONDAY AND WILL STALL SOUTH OF THE REGION MONDAY NIGHT AND TUESDAY WHILE LOW PRESSURE DEVELOPS ALONG IT. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... ---1145AM UPDATE--- PRECIPITATION HAS CLEARED THE COAST SO WILL UPDATE TO DROP MENTION OF SHOWERS THIS AFTERNOON. CLOUD COVER AND CEILINGS WIDELY VARIED AND WILL CONTINUE TO COMPLICATE TAF FORECASTS THROUGH EARLY AFTERNOON. ---920AM UPDATE--- BACK EDGE OF PRECIPITATION MOVING INTO WESTERN PORTIONS OF CWA THIS MORNING. EXPECT PRECIPITATION TO MOVE OFFSHORE BY AROUND NOON. WILL UPDATE FORECAST PACKAGE TO ACCOUNT FOR THE TIMING AND MINOR TEMPERATURE ADJUSTMENTS. 605 AM...MINOR ESTF UPDATE TO REFLECT RADAR TRENDS AND TO INGEST THE LATEST MESONET INTO 1ST PERIOD GRIDS. PREV DISC... CLOUDS...AND AN AREA OF SHOWERS ON NWS DOPPLER RADAR MOSAIC...WERE RACING EASTWARD INTO NEW ENGLAND AHEAD OF AN IMPULSE EVIDENT ON GOES WATER VAPOR IMAGERY...ALONG WITH ASSOCIATED SURFACE SYSTEM. SHOWERS SHOULD END BY EARLY AFTERNOON AS WEAK SURFACE COLD FRONT AND UPPER SUPPORT SLIDES OFFSHORE...WITH DECREASING CLOUD COVER. HIGHS TODAY WILL BE UPPER 50S TO MID 60S...BUT A BIT COOLER MID COAST MAINE GIVEN AN ONSHORE TRAJECTORY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/... THE SECOND COLD FRONT WILL SAG SOUTH ACROSS THE REGION TONIGHT ALONG WITH A FEW CLOUDS. THIS SETS THE STAGE FOR SATURDAY WHEN A FAST MOVING IMPULSE AND ASSOCIATED SURFACE LOW WILL TRACK SOUTHEAST ALONG THIS BOUNDARY. CLOUDS WILL INCREASE QUICKLY FROM NORTHWEST TO SOUTHEAST AND SHOWERS EXPAND IN COVERAGE. GIVEN THE STEEPENING LAPSE RATES...WOULDN`T BE SURPRISED TO SEE SOME ISOLATED THUNDER. && .LONG TERM /SATURDAY THROUGH THURSDAY/... LOW PRESSURE WILL DEPART SATURDAY EVENING BRINGING AN END TO ANY RAIN OR SNOW SHOWERS ACROSS NORTHERN AND EASTERN ZONES. OUR ATTENTION THEN TURNS TOWARD POTENTIAL COASTAL LOW PRESSURE FOR EARLY NEXT WEEK. THE VARIOUS MODELS HAVE SHOWN VERY GOOD RUN TO RUN CONSISTENCY WITH THE TRACK OF LOW PRESSURE MONDAY AND TUESDAY AND THE POTENTIAL FOR A PERIOD OF HEAVY RAINFALL...ESPECIALLY LATE MONDAY NIGHT AND TUESDAY MORNING. 1 TO 2 INCHES WILL BE POSSIBLE WITH LOCALLY HIGHER AMOUNTS. AT THIS TIME...HIGHEST AMOUNTS LOOK TO BE ACROSS SOUTHERN NH AND THE ME COASTAL PLAIN. THIS ALONG WITH SNOWMELT WILL CAUSE RIVER RISES...PERHAPS SOME SIGNIFICANT. ALONG WITH THE RAIN...THE MODELS ON AVERAGE HAVE COOLED FOR THE FAR INTERIOR. THE ECMWF REMAINS THE COLDEST MODEL WHICH HAS BEEN A CONSISTENT THEME FOR THE LAST 4 OR 5 RUNS. IF THE ECMWF WERE TO VERIFY...A HEAVY WET SNOW EVENT WOULD OCCUR IN THE WESTERN ME MOUNTAINS...AND PERHAPS PORTIONS OF THE FOOTHILLS MONDAY NIGHT INTO TUESDAY. WILL HAVE TO WATCH FOR THIS POSSIBILITY. FOR NOW HAVE BLENDED THE COLDER ECMWF IN BUT HAVE NOT TOTALLY BOUGHT IT LOCK STOCK AND BARREL. HOWEVER...THE RESULT WAS SEVERAL HOURS OF SNOW FOR THE WESTERN MAINE MOUNTAINS WITH PLOWABLE AMOUNTS FOR THE HIGHER ELEVATIONS. ANOTHER ISSUE OF NOTE IS THAT ASTRONOMICAL TIDES WILL BE QUITE HIGH MONDAY NIGHT AND TUESDAY. IF THE MODEL CONSENSUS HOLDS...EAST WINDS AND BUILDING SEAS WILL COMBINE WITH A 11.5 FT TIDE AT PORTLAND. THIS WILL HAVE TO BE WATCHED FOR THE POTENTIAL FOR COASTAL FLOODING...ESPECIALLY MONDAY NIGHT INTO TUESDAY MORNING. AFTER TUESDAY...ANOTHER WEAKER SYSTEM LOOKS TO AFFECT THE REGION WITH RAIN AND SNOW SHOWERS WEDNESDAY AND WEDNESDAY NIGHT. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... SHORT TERM...DEVELOPING MVFR WITH LCL IFR THIS MORNING IN SHOWERS...IMPROVING TO VFR THIS AFTERNOON AND TONIGHT. AREAS OF MVFR DEVELOPING SATURDAY IN SHOWERS WITH ISOLD THUNDERSTORMS PSBL. LONG TERM...VFR CONDITIONS SATURDAY NIGHT INTO MONDAY. THEREAFTER...IFR CONDITIONS IN RAIN ARE LIKELY STARTING MONDAY AFTERNOON AND LASTING THROUGH TUESDAY. && .MARINE... SHORT TERM...SCA`S CONTINUE THROUGH TODAY FOR OUR EASTERN OUTER WATERS. THIS WILL BE DUE TO A COMBINATION OF INCREASING SOUTH WINDS AND BUILDING SEAS. ELSEWHERE WINDS AND SEAS WILL REMAIN BELOW SCA CRITERIA. EXPECT WE`LL BE BELOW SCA THRESHOLD ACROSS THE AREA TONIGHT AND SATURDAY. LONG TERM...LOW PRESSURE AFFECTING THE WATERS MON NIGHT AND TUE WILL LIKELY BRING ROUGH SEAS AND SCA CONDITIONS...IF NOT LOW END GALES FOR A TIME. && .FIRE WEATHER... SHOWERS AND HIGH RELATIVE HUMIDITIES EXPECTED THIS MORNING. BY AFTERNOON CLEARING TAKES PLACE BUT RH VALUES REMAIN HIGH AS WINDS BECOME WEST BUT GENERALLY AROUND 10 MPH. COOLER TEMPERATURES AND SHOWERS RETURN ON SATURDAY. THE OUTLOOK FOR MONDAY INTO TUESDAY SHOWS POTENTIAL FOR A SOAKING RAIN BEGINNING LATE MONDAY AND CONTINUING INTO TUESDAY. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR ANZ150- 152. && $$ POHL

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.