Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 311843 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 243 PM EDT FRI JUL 31 2015 .SYNOPSIS... A WEAK COLD FRONT WILL CROSS THE AREA SATURDAY...BRINGING ANOTHER THREAT FOR SHOWERS AND THUNDERSTORMS. BEHIND THIS FRONT WE WILL SEE ANOTHER DROP IN TEMPERATURES AND HUMIDITY. WEAK LOW PRESSURE ALOFT...SITUATED OVER QUEBEC...WILL BRING A THREAT FOR SHOWERS OR STORMS MONDAY AND TUESDAY. COOLER AIR AND UNSETTLED CONDITIONS MOVE IN FOR THE MIDDLE TO END OF NEXT WEEK. BY LATE IN THE WEEK...LOW PRESSURE MAY FORM ALONG THE MID ATLANTIC SEABOARD...BRINGING MORE RAIN TO OUR REGION. && .NEAR TERM /THROUGH TONIGHT/... AT 18Z...A WEAK SURFACE TROUGH WAS EXITING THE COAST...WITH A SURFACE COLD FRONT SITUATED OVER THE GREAT LAKES. GOES WATER VAPOR SHOWED AN UPPER LOW CENTERED OVER HUDSON BAY. ANOTHER WARM DAY ACROSS THE AREA...BUT NOTICEABLY LESS HUMID AS WESTERLY FLOW INTRODUCED DRIER AIR BEHIND THE FRONT. INSTABILITY CLOUDS WILL MELT AWAY THIS EVENING WITH LOSS OF HEATING. OVER NIGHT...OUTSIDE OF A FEW STRAY CLOUDS FOR THE MOUNTAINS...MOSTLY CLEAR WITH [PATCHY LATE NIGHT VALLEY FOG. LOWS WILL RANGE FROM 50S IN THE MOUNTAINS TO LOWER AND MID 60S ELSEWHERE. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... ON SATURDAY...A SHORTWAVE IMPULSE PIVOTING AROUND THE UPPER LOW WILL CROSS THE AREA ALONG WITH AN ASSOCIATED COLD FRONT. HIGH TEMPERATURES WILL WARM INTO THE 70S AND 80S. WITH COOLER AIR MOVING IN ALOFT...AND LOWERING FREEZING LEVELS...SOME OF THE STRONGER CELLS MAY PRODUCE HAIL NEAR SEVERE THRESHOLD...ALONG WITH STRONG WIND GUSTS. THE BEST CONVECTIVE COVERAGE WILL BE FAR NORTHERN NEW HAMPSHIRE INTO THE MOUNTAINS AND FOOTHILLS OF MAINE. FOR NOW...I`VE LIMITED ENHANCED WORDING TO GUSTY WINDS AND SMALL HAIL AND CONFINED THE AREA TO FAR NORTHERN AND EASTERN SECTIONS OF THE FORECAST AREA GIVEN SOME CONTINUED UNCERTAINTIES. CONVECTION SHOULD END QUICKLY SATURDAY EVENING WITH LOSS OF HEATING AND AS COLD FRONT CLEARS THE COAST. SOME CLOUDS AND WIDELY SCATTERED SHOWERS COULD LINGER IN THE HIGHER TERRAIN...OTHERWISE A MAINLY CLEAR AND SEASONABLY COOL NIGHT WITH LOWS IN THE LOWER AND MID 50S IN THE MOUNTAINS...AND IN THE 50S TO AROUND 60 ELSEWHERE. && .LONG TERM /SUNDAY THROUGH FRIDAY/... A HIGHLY PERSISTENT PATTERN WILL CONTINUE ACROSS THE CONUS OVER THE NEXT WEEK OR SO. A LARGE UPPER LEVEL RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE WESTERN UNITED STATES WHILE A PERSISTENT CYCLONIC FLOW CONTINUES OVER THE NORTHEAST. A MORE SIGNIFICANT UPPER LEVEL LOW WILL BEGIN TO DIG SOUTHWARD FROM CANADA ON MONDAY. THIS...IN CONJUNCTION WITH A SLOW MOVING COLD FRONT WILL CROSS NEW ENGLAND LATE IN THE DAY AND IN THE EVENING HOURS. EXPECT ISOLATED SEVERE WEATHER WITH THE POTENTIAL FOR LARGE HAIL AND DAMAGING WINDS WHICH WILL CONTINUE INTO MONDAY NIGHT. STRONG CYCLONIC FLOW ALOFT WILL ALLOW FOR MORE SCATTERED SHOWERS ON TUESDAY WITH POSSIBLY A THUNDERSTORM. SIMILAR CONDITIONS WILL OCCUR ON WEDNESDAY...WITH MAINLY DIURNALLY DRIVEN SHOWERS DUE TO STEEP LAPSE RATES ASSOCIATED WITH VERY COLD AIR ALOFT. THE MORNINGS WILL LIKELY BEGIN WITH PLENTY OF SUNSHINE...WITH CLOUDS QUICKLY BUILDING AND THICKENING OVER THE REGION WITH THE DAYTIME HEATING. ON FRIDAY...CYCLOGENESIS WILL LIKELY OCCUR ALONG THE SOUTHERN NEW ENGLAND COASTLINE WITH YET MORE UPPER LEVEL ENERGY DIGGING SOUTH FROM CANADA. THIS SLOW MOVING SYSTEM IN COMBINATION WITH DEEP TROPICAL MOISTURE WILL LIKELY BRING PERIODS OF HEAVY RAINFALL NEXT WEEKEND. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... SHORT TERM /THROUGH 12Z SAT/...SCT MVFR PSBL BTW 08 - 12Z SAT IN VALLEY FOG AND STRATUS. SCT MVFR 16 SAT - 00Z SUN IN SHRA AND TSRA. SCT MVFR PSBL ONCE AGAIN BTW 08 - 12Z SUN IN VALLEY FOG AND STRATUS. LONG TERM...MAINLY VFR SAT NIGHT THROUGH TUESDAY... WITH VLY FOG POSSIBLE EACH NIGHT. SCT SHRA/TSRA WILL IMPACT MOST OF THE TERMINALS LATE MON AND MON NIGHT. && .MARINE... SHORT TERM /THROUGH SATURDAY NIGHT/...SOUTHERLY FLOW LATE SAT AND SAT EVENING MAY BRIEFLY APPROACH SMALL CRAFT OUTSIDE THE BAYS AHEAD OF A COLD FRONT...OTHERWISE QUIET WEATHER IS EXPECTED THIS PERIOD. LONG TERM...PERSISTENT SW FLOW SUNDAY AND MONDAY COULD BRING HIGHER SWELLS TO THE COASTLINE SUNDAY NIGHT....WHICH COULD LINGER THROUGH TUESDAY. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$

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