Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 240129 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 829 PM EST TUE DEC 23 2014 .SYNOPSIS... AN ONSHORE FLOW WILL CONTINUE TONIGHT. A SIGNIFICANT LOW PRESSURE SYSTEM WILL MOVE ACROSS THE GREAT LAKES WEDNESDAY INTO THURSDAY. THIS WILL BRING WINDY CONDITIONS AND THE POTENTIAL FOR HEAVY RAIN CHRISTMAS EVE INTO CHRISTMAS MORNING. ANOTHER LOW PRESSURE SYSTEM WILL APPROACH THE REGION EARLY NEXT WEEK POTENTIALLY BRINGING SOME WINTRY WEATHER. && 01Z UPDATE... UPDATING ZONES TO INCLUDE THE FOOTHILLS OF MAINE AND NEW HAMPSHIRE IN THE FREEZING RAIN ADVISORY FOR OVERNIGHT. SPOTTERS REPORTING SOME FREEZING DRIZZLE IN THESE AREAS AND MESO-NET OBS COMFIRMING FREEZING TEMPS IN VALLEY LOCATIONS. BAND OF RAIN SHOWERS CURRENTLY PUSHING NORTHEAST THROUGH CENTRAL NEW HAMPSHIRE AND SOUTHWEST MAINE AND EXPECT THIS AREA TO CONTINUE OFF TO THE NORTHEAST THROUGH MIDNIGHT. BEHIND THIS AREA JUST EXPECT MAINLY FREEZING DRIZZLE OVERNIGHT WITH SOME LIGHT ICE ACCUMULATIONS. OTHER THAN A FEW TEMP TWEAKS NO OTHER CHANGES PLANNED ATTM. PREVIOUS FORECAST DISCUSSION... .NEAR AND SHORT TERM /THROUGH WEDNESDAY NIGHT/... THE COMBO OF THE MOIST EASTERLY ONSHORE FLOW AND THE WAA ALOFT FROM THE SOUTH WILL ALLOW PERIODS OF RAIN AND DRIZZLE TO CONTINUE THROUGH TONIGHT. IN THE WESTERN MTNS OF MAINE SFC TEMPS WILL BE COLD ENOUGH TO ALLOW SOME FREEZING RAIN TO OCCUR SO A FREEZING RAIN ADVISORY REMAINS IN EFFECT FOR THOSE AREAS. AREAS OF FOG WILL ALSO BE NOTED AS THE INVERSIONS ALLOW THE LOW LEVELS TO BECOME SUPERSATURATED. ON WED A CONTINUED SHALLOW LOW LEVEL NELY FLOW WILL CONTINUE WHILE ALOFT VERY WARM AIR CONTINUES TO MOVE ACROSS THE AREA. RAIN WILL CONTINUE THROUGH THE DAY IN AL AREAS AND BY LATER IN THE DAY WILL BECOME HEAVY AT TIMES AND CONTINUE THROUGH WED NIGHT. THE SOURCE REGION FOR THE SYSTEM APPROACHING IS FROM THE GULF OF MEXICO AND MOVES NORTH UP THE EAST COAST. MODELS BRING ABOUT 1.5 INCHES OF QPF ACROSS THE AREA BUT THAT MAY BE LOW CONSIDERING THE LATEST LOOK AT THE WATER VAPOR AND ALSO CONSIDERING THE PWAT VALUES. NEEDLESS TO SAY, WENT CATEGORICAL POPS WED AND WED NIGHT. FOG WILL ALSO BECOME MORE OF AN ISSUE LATE WED AND WED NIGHT DUE TO SUPERSATURATION OF THE WARM TEMPS/HIGH DEWPTS RIDING OVER THE COOLER SFC. ANOTHER ISSUE WILL BE WHETHER THE STRONG LOW/MID LEVEL JET CAN MIX DOWN TO THE SFC AND CAUSE SOME STRONG GUSTY WINDS WED NIGHT...BUFKIT SHOWS THESE STRONG WINDS DOWN TO 1K FT ABOVE THE SFC. FOR TEMPS USED A BLEND OF THE CMC/NAMDNG5/LOCAL WRF WHICH DEPICTED TEMPS BETTER THAN THE SUPERBLEND. FOR QPF STAYED CLOSE TO THE RFCQPF GUIDANCE. && .LONG TERM /THURSDAY THROUGH TUESDAY/... STRONG COLD FRONT WILL CROSS THE REGION THURSDAY MORNING. WARM SECTOR SHOULD BE IN PLACE ACROSS AT LEAST SOUTHERN AND COASTAL ZONES BEFORE FROPA...SO HIGHS 55 TO 60 POSSIBLE. WIND GUSTS MAY BE STRONG PRIOR TO AND AFTER COLD FRONTAL PASSAGE...ESPECIALLY SOUTHERN AREAS THAT WARM SECTOR AND CAN MORE RAPIDLY MIX DOWN HIGHER MOMENTUM AIR. A FEW THUNDERSTORMS WILL BE POSSIBLE AHEAD OF THE FRONT LATE WED NIGHT INTO THURS MORNING AS WELL. FRONT SWEEPS OFFSHORE DURING THE MORNING ALLOWING FOR GUSTY AND CLEARING CONDITIONS FOR THURSDAY AFTERNOON. FAIR WEATHER FOLLOWS IN THE FRONT/S WAKE FOR FRI AND SAT. A COLD FRONT PASSING THROUGH THE AREA LATER SAT NIGHT AND SUN MAY BRING A PERIOD OF LIGHT RAIN AND/OR SNOW. THEREAFTER...WE/LL HAVE TO WATCH FOR A POTENTIAL WINTRY SITUATION EARLY NEXT WEEK. MODEL RUN TO RUN CONSISTENCY HAS BEEN A BIT SKETCHY WITH THIS SYSTEM UP TO THIS POINT...SO CONFIDENCE IS LOW. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... SHORT TERM...IFR TO LIFR CONDITIONS ARE EXPECTED TONIGHT THROUGH WEDNESDAY NIGHT IN RAIN/DRZL/AREAS OF FOG. LLWS EXPECTED WEDNESDAY NIGHT. LONG TERM...IFR CONDITIONS AND LLWS EXPECTED THURS MORNING. COLD FRONT SWEEPS OFFSHORE BY MIDDAY THURS ALLOWING CONDITIONS TO IMPROVE MARKEDLY. HOWEVER...SFC WIND GUSTS AROUND 40 KT WILL BE POSSIBLE THURS. VFR CONDITIONS ARE EXPECTED FRI AND SAT...WITH MVFR POSSIBLE WITH COLD FRONT SUN. && .MARINE... SHORT TERM...HAVE INCREASED WIND AND WAVE FIELDS FROM CURRENT OPERATIONAL GUIDANCE FOR TONIGHT THROUGH WED NIGHT FOR THE SHORT TERM PORTION OF THE FORECAST. MODELS CONTINUE TO BE OVERLY WEAK IN HANDLING WIND AND WAVE CONDITIONS FOR THIS EVENT. GALE WARNINGS HAVE BEEN ISSUED FOR BEGINNING WED EVENING. ALTHOUGH SCA CONDS WILL CONTINUE TONIGHT AND WED, WE HAVE DROPPED THE SCA TO AVOID A DOUBLE HEADLINE. LONG TERM... THU...GALE FORCE WINDS ARE LIKELY THU AND THU NIGHT IN THE WAKE OF A COLD FRONT. SCA WINDS AND SEAS WILL THEN BE POSSIBLE FRI INTO THE WEEKEND. && .HYDROLOGY... A FLOOD WATCH HAS BEEN ISSUED FROM 00Z/25TH-00Z/26TH. THE MODELS CONTINUE TO INDICATE AROUND 1.5 INCHES OF QPF WHICH IS IN LINE WITH THE RFCQPF FCST. HOWEVER...CONSIDERING THE SOURCE REGION FOR THIS SYSTEM COMING FROM THE GULF OF MEXICO AND MODEL TRAJS SHOWING THAT MUCH OF THIS TROPICAL AIR MASS WILL MOVE NORTH UP THE COAST INTO OUR REGION. CONSIDERING THE VERY HIGH PWATS FORECAST, THE MODELS MAY BE OFF BY AN INCH OR TWO. IF SO, RIVERS WILL RESPOND SO THE WATCH HAS BEEN ISSUED. CURRENTLY ALL OUR RIVERS ARE FORECAST TO REMAIN JUST BELOW FLOOD STAGES ASSUMING TOTAL RAINFALL OF AROUND 1.5 INCHES. URBAN AND POOR DRAINAGE FLOODING IS LIKELY. && .TIDES/COASTAL FLOODING... HAVE ISSUED A COASTAL FLOOD WATCH FOR THE 11.2 FT HIGH TIDE WEDNESDAY AT 1216 PM. THE PERSISTENT EASTERLY WINDS WILL BRING THE PORTLAND AND HAMPTON TIDES NEAR FLOOD STAGE AS WE APPROACH OUR HIGHEST ASTRONOMICAL TIDES OF THE MONTH. MINOR COASTAL FLOODING, SPLASHOVER AND BEACH EROSION IS POSSIBLE AT THE TIME OF HIGH TIDE DUE TO THE COMBINATION OF THE HIGH TIDES AND ALSO BUILDING SEAS. && .CLIMATE... RECORD HIGH TEMPERATURES COULD BE TIED OR SET AND PWM AND CON CHRISTMAS DAY. THE HIGHEST CHRISTMAS DAY TEMPERATURES ON RECORD ARE 56 FOR CONCORD IN 1889 AND 53 AT PORTLAND IN 1994. OUR CURRENT FORECAST HIGH TEMPERATURES BREAK BOTH RECORDS. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...FLOOD WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING FOR MEZ007>009-012>014-018>022. FREEZING RAIN ADVISORY UNTIL 8 AM EST WEDNESDAY FOR MEZ007>009- 012>014. COASTAL FLOOD WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON FOR MEZ023-024. NH...FLOOD WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY EVENING FOR NHZ001>013-015. FREEZING RAIN ADVISORY UNTIL 8 AM EST WEDNESDAY FOR NHZ001>004. COASTAL FLOOD WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY AFTERNOON FOR NHZ014. MARINE...GALE WARNING FROM 7 PM WEDNESDAY TO 7 PM EST THURSDAY FOR ANZ150>154. && $$

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