Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 311418 CCA AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 1015 AM EDT SUN AUG 31 2014 .SYNOPSIS... THE RETURN FLOW AROUND HIGH PRESSURE CENTERED OFFSHORE WILL BRING INCREASINGLY HUMID AIR INTO THE REGION THROUGH TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST TODAY PRODUCING SHOWERS AND THUNDERSTORMS WITH GUSTY WINDS AND LOCALLY HEAVY RAINFALL. THE FRONT IS EXPECTED TO STALL NEARBY ON MONDAY. ANOTHER FRONT WILL CROSS THROUGH THE REGION LATE TUESDAY AND TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE THROUGH THE END OF THE WORK WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 10 AM UPDATE...NO SIGNIFICANT CHANGES TO THE FORECAST AT THIS TIME. SHOWERS ACROSS THE NORTH HAVE WANED AS OF 10 AM. MODERATE HEATING IS NOW TAKING PLACE THROUGH BREAKS IN THE CLOUDS SOUTHERN AND COASTAL ZONES. AS SUCH...TEMPERATURES ARE RISING WELL INTO THE 70S WITH DEWPOINTS ON THE RISE AS WELL. THIS SHOULD AID IN THE DEVELOPMENT OF AROUND 1000 J/KG SBCAPE BY MID AFTERNOON. AS A SHORT WAVE TROUGH APPROACHES FROM THE WEST THIS AFTERNOON...FORCING FOR ASCENT SHOULD AID IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. SOME COULD BE STRONG. THE MAIN THREAT WOULD BE GUSTY WINDS AND TORRENTIAL RAINFALL. THE HIGHEST PROBABILITY FOR THIS LOOKS TO BE OVER SOUTHERNMOST MAINE AND SOUTHERN NH WHERE INSTABILITY AND PWATS WILL BE GREATEST. THERE IS A LOW PROB OF LOCALIZED FLASH FLOODING VERY LATE THIS AFTERNOON INTO THE EARLY EVENING ACROSS THIS AREA IF STORMS TRAIN. PWATS ARE EXPECTED TO EXCEED 2 INCHES IN THIS AREA. PREV DISC... AT 06Z...A FRONTAL BOUNDARY EXTENDED FROM CENTRAL QUEBEC THROUGH ONTARIO TO A 1008 MILLIBAR LOW VCNTY OF LK HURON WITH A TRAILING COLD FRONT THROUGH MICHIGAN AND TEH UPPER MIDWEST. A 1026 MILLOBAR HIGH WAS SITUATED WELL OFFSHORE TO OUR EAST. A BROAD SOUTHWEST RETURN FLOW BEHIND THE HIGH AND THE APPROACHING COLD FRONT WAS INTRODUCING INCREASINGLY HUMD AIR INTO THE FORECAST AREA. WE`LL SEE SOME LOW CLOUDS AND PATCHY FOG THIS MORNING...THEN MOSTLY CLOUDY SKIES WITH AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS. THE MODIFIED BUFKIT SOUNDINGS SHOW CAPES BETWEEN 1000 AND 1500 J/KG OVER SOUTHWEST MAINE AND SOUTHERN NEW HAMPSHIRE LATER TODAY WITH PRECIPITABLE WATER VALUES AROUND 2 INCHES. SOME STORMS WILL CONTAIN GUSTY WINDS THAT COULD APPROACH SEVERE CRITERIA...ALONG WITH TORRENTIAL RAIN THAT IF TRAINING OF ECHOES OCCURS WILL PROVIDE A RISK FOR LOCALIZED FLASH FLOODING. HIGHS TODAY WILL RANGE FROM 70S IN THE MOUNTAINS TO THE LOWER 80S ELSEWHERE. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... SHOWER AND THUNDERSTORM ACTIVITY WILL WANE BY MID TO LATE EVENING. HOWEVER...WITH THE FRONTAL BOUNDARY EXPECTED TO STALL NEARBY...A WARM AND MUGGY NIGHT SHOULD REMAIN IN THE CARDS TONIGHT. WITH BOUNDARY STALLED NEARBY...EXPECTED SCATTERED CONVECTION TO FIRE ONCE AGAIN ON MONDAY. ANOTHER COLD FRONT WILL CROSS NEW ENGLAND NEXT WEEKEND. THERE WILL BE ADDITIONAL MOISTURE ASSOCIATED WITH THIS FRONTAL PASSAGE. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... 00Z MODEL SUITE ARE IN GOOD AGREEMENT WITH THE TIMING AND PASSAGE OF ANOTHER COLD FRONT LATE TUESDAY AND TUESDAY NIGHT. THIS SYSTEM WILL TRIGGER MORE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. THEREAFTER...HIGH PRESSURE BUILDS IN FROM THE WEST. THIS WILL BRING A DRY PERIOD TO MAINE AND NEW HAMPSHIRE LATER IN THE WEEK. && .AVIATION /10Z SUNDAY THROUGH THURSDAY/... .SHORT TERM...SOME FOG AND STRATUS EARLY TODAY...ESPECIALLY NEAR THE COAST AND IN RIVER VALLEYS. THIS MAY LEAD TO A 3 TO 6 HOUR PERIOD OF IFR CONDITIONS IN SPOTS THIS MORNING. OTHERWISE... SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE DAY WITH THEIR ASSOCIATED LOWER CONDITIONS AND GUSTY SFC WINDS/HEAVY RAINFALL. FOG AGAIN TONIGHT WITH AREAS OF MVFR AND LCL IFR. ON MONDAY...VFR WITH LCL MVFR IN SCT SHOWERS AND TSTMS. .LONG TERM...SOME IFR CONDITIONS IN SCATTERED SHOWERS AND STORMS LATE TUESDAY AND TUESDAY NIGHT. OTHERWISE...VFR THROUGH THE PERIOD. && .MARINE... .SHORT TERM... WINDS AND SEAS SHOULD REACH MARGINAL SMALL CRAFT CONDITIONS TODAY OUTSIDE THE BAYS IN SOUTHWEST FLOW...BEFORE DIMINISHING THIS EVENING. .LONG TERM... WINDS AND SEAS WILL BE BELOW SCA CRITERIA THROUGH THE PERIOD. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ150-152- 154. && $$ NEAR TERM UPDATE...MLE

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