Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 271008 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 608 AM EDT WED AUG 27 2014 .SYNOPSIS... A COLD FRONT WILL DROP SOUTH THROUGH THE REGION TODAY AND COULD SET OFF SOME SHOWERS AND THUNDERSTORMS...BUT NOT BEFORE TEMPERATURES WARM TO NEAR 90 DEGREES AGAIN IN MANY SPOTS. COOLER HIGH PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST THURSDAY AND FRIDAY AND SHIFT OFFSHORE ON SATURDAY. A WARM FRONT CROSSES THE AREA SATURDAY NIGHT INTO SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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605 AM...FORECAST UPDATE TO COVER SHRA MOVING ACROSS FAR NRN ZONES BEING FORCED BY WEAK 500MB WAVE AND PRE-FRONTAL TROUGHING. A FEW SHRA WILL BE POSSIBLE HERE THROUGH ABOUT 12Z. OTHERWISE TWEAKED T/TD/SKY FOR THE MORNING BASED ON CURRENT OBS...BUT OVERALL FORECAST THINKING UNCHANGED FOR THE REST OF THE DAY. PREVIOUSLY FOR TODAY...WILL LKLY SEE A MAINLY DRY DAY AFTER SUNRISE THROUGH EARLY TO MID AFTERNOON WHEN THE ACTUAL SFC FRONT BEGINS TO DROP SE ACROSS THE CWA. WHILE A SHRA OR TSRA CANNOT BE RULE OUT ANYWHERE WITH THE FROPA...GIVEN DECENT INSTABILITY...THE LACK OF ANY DYNAMICS AND A REAL TRIGGER DOES NOT BODE WELL FOR ANY WIDESPREAD CONVECTION. NAM12 AND MESOSCALE MODELS CONTINUE TO FOCUS CONVECTION DEVELOPMENT MID TO LATE AFTERNOON CLOSER TO THE COAST...PROBABLY ON THE SEA BREEZE BOUNDARY...AND THIS WHERE THE 30ISH CHC POPS ARE...FROM ABOUT 19-23Z. THERE ARE DECENT SHEAR PROFILES AHEAD OF THE FRONT...AND INSTABILITY GETS IN THE 1000-1500 J-KG RANGE...SO THERE IS AN OUTSIDE CHC THAT AN ORGANIZED CELL CAN GET A LITTLE ROTATION...ASSUMING A SUSTAINED UPDRAFT CAN GET GOING. MAX TEMPS ON THE COASTAL PLAIN AWAY FROM THE IMMEDIATE COAST SHOULD MAKE A RUN AT 90 AGAIN...GIVEN INCREASED WSW FLOW...WHICH WILL DOWNSLOPE AND HELP OUT THE HEATING. COASTAL AREAS THAT DO WELL WITH DOWNSLOPE...KPWM...COULD GET CLOSE TO 90...DEPENDING ON TIMING OF FROPA AND WHETHER ANY CONVECTION DEVELOPS IN THE AREA.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... ANY LINGERING SHRA/TSRA SHOULD WIND DOWN OR MOVE OFFSHORE BY 01-02Z. GIVEN THAT MID-UPPR LVL FLOW WILL NOT SHIFT THAT MUCH BEHIND THE FRONT IT IS UNLIKELY THAT WINDS WILL MIX DOWN ONCE THE FRONT MOVES THROUGH COASTAL AREAS. THIS WILL MEAN THAT LOW LVL MOISTURE WILL LINGER THRU THE NIGHT...AND NOT ONLY WILL KEEP MINS IN THE LOW TO MID 60S...BUT COULD SEE SOME FOG OR LOW STRATUS DEVELOPING IN SPOTS ON THE COAST. IN THE MTNS AND FOOTHILLS LOOK FOR MINS TO DROP OFF INTO THE 50S...WITH SOME PARTIAL CLEARING. COOLER DRIER WILL MIX DOWN AFTER SUNRISE THU MORNING...AND SHOULD SEE GOOD CLEARING WITH MOSTLY SUNNY SKIES ON THE COAST...AND ENOUGH OF A NW WIND FOR DOWNSLOPING TO PUSH TEMPS INTO THE MID TO UPPER 70S. IN THE MTNS UPSLOPE FLOW WILL PROVIDE A FAIR AMT OF CLOUDS...AND PERHAPS A FEW SHRA WITH HIGHS ONLY REACHING TO AROUND 70. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... THE MODELS ARE IN GENERAL AGREEMENT ON THE LONG WAVE PATTERN THROUGH EARLY NEXT WEEK. A RIDGE WILL SLIDE EAST ACROSS THE AREA FOR THURSDAY ND FRIDAY. THE RIDGE WILL SLIDE OFFSHORE BY SATURDAY WITH THE RETURN FLOW USHERING WARMER AND MORE HUMID AIR INTO THE REGION FOR THE HOLIDAY WEEKEND. A SLOW-MOVING COLD FRONT WILL DROP SOUTHEAST AND PROVIDE AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS AS WE HEAD THROUGH THE HOLIDAY WEEKEND. THE FRONT WILL STALL ACROSS THE REGION EARLY NEXT WEEK BEFORE RETURNING NORTH AS A WARM NEXT WEDNESDAY. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... .SHORT TERM...GIVEN AN INCREASING SW FLOW ABV THE BOUNDARY LYR...MAY NOT SEE TOO MUCH IN THE WAY OF FOG THIS AM...BUT CANNOT RULE OUT KLEB/KCON/KHIE DROPPING TO IFR FOR A COUPLE HRS AROUND SUNRISE. OTHERWISE MAINLY VFR TODAY WITH A CHC OF A TSRA MID TO LATE AFTERNOON AT THE COASTAL TERMINALS. OUTSIDE CHC OF SOME FOG AND STRATUS AT THE COASTAL TERMINALS LATER TONIGHT. .LONG TERM... SAT NIGHT - SUN...AREAS OF MVFR IN SHOWERS AND TSTMS. && .MARINE... .SHORT TERM...HAVE DROPPED THE SCA FOR TODAY ACROSS ALL BUT THE WATERS S OF PENOBSCOT BAY...WHERE INCREASING SWELL WILL PUSH SEAS UP TO 5 FT TODAY AND WITH SW WINDS APPROACHING 15 KTS...COULD BE QUITE CHOPPY. SWELL FROM CRISTOBAL COULD INCREASE TO CLOSER TO 6 FT LATE TONIGHT INTO THU...AND MAY NEED TO PUSH SCA FURTHER WEST LATER. .LONG TERM... SAT NIGHT - SUN...SMALL CRAFT WINDS AND SEAS ARE POSSIBLE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THURSDAY FOR ANZ150. && $$ SYNOPSIS... NEAR TERM...CEMPA SHORT TERM... LONG TERM... AVIATION... MARINE...

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