Area Forecast Discussion
Issued by NWS Portland, ME

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000 FXUS61 KGYX 121021 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 621 AM EDT SAT JUL 12 2014 .SYNOPSIS... HIGH PRESSURE MOVES OFF THE COAST TODAY GIVING US ANOTHER PLEASANT SUMMER DAY. A WARM FRONT PUSHES TO THE NORTHEAST TONIGHT BRINGING IN MORE HUMID AND UNSTABLE AIR ON SUNDAY WITH AN INCREASING RISK OF SHOWERS AND THUNDERSTORMS. THE WARM HUMID AIRMASS WILL LINGER FOR MONDAY AND TUESDAY IN ADVANCE OF A SLOW-MOVING COLD FRONT. THE COLD FRONT IS EXPECTED TO EXIT THE COAST BY LATE WEDNESDAY. HIGH PRESSURE WILL BUILD TO THE SOUTH OF THE AREA THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... UPDATED TO INPUT LATEST OBSERVED DATA RESULTING IN NO MORE THAN A FEW MINOR TWEAKS TO THE PREVIOUS FCST. SOME PATCHY F AROUND IN CT VALLEY AND A FEW OTHER ISOLATED SPOTS...BUT SHOULD BURN OFF OVER THE NEXT COUPLE HOURS. THE SFC HIGH SLIDES OFFSHORE TODAY GIVING US LOTS OF SUNSHINE TODAY. A RETURN FLOW OF S SW WINDS WILL BRING IN WARMER AIR OVER INLAND AREAS...ESPECIALLY NH INTO THE ME MT/FOOTHILL ZONES...WITH HIGHS EXPECTED TO REACH THE 80S WITH SOME UPPER 70S IN THE MOUNTAINS. THE S SW FLOW WILL BE ENHANCED BY A SEA BREEZE BRINGING IN COOLER OCEAN AIR ALONG THE COAST. THIS WILL LIMIT HIGHS IN THE 70S ALONG THE COAST...WITH THE MID COAST THE COOLEST WITH HIGHS BARELY REACHING THE LOWER 70S ALONG THE IMMEDIATE SHORELINE. WITH THE PRESSURE GRADIENT FROM THE S SW THE COOL OCEAN AIR WILL PUSH INLAND...JUST SHORT OF THE FOOTHILLS THIS AFTERNOON WHICH WILL LEVEL OFF TEMPS AT PLACES LIKE LEW...AUG AND WVL. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/... A WARM FNT SURGES TO THE NE TNGT AS THE HIGH DRIFTS FURTHER OUT TO SEA. THUS CLOUDS WILL BE ON THE INCREASE TNGT WITH LOW TEMPS MILDER THAN LAST NGT...EXPECTING LOWS IN THE 50S N AND UPPER 50S TO LOWER 60S S. DEW POINTS WILL BE ON THE RISE AS WELL SUCH THAT TEMP DEW POINT SPREADS WILL BE VERY SMALL WHICH MAY ALLOW FOR SOME F TO FORM...THOUGH INCREASING CLOUDS WILL OFFSET THAT TO SOME DEGREE. THE WARM FNT WILL USHER IN A WARMER...MORE HUMID AND UNSTABLE AIR MASS FOR SUNDAY. THE INSTABILITY AS BEST SHOWN BY CAPE VALUES AND NEGATIVE LI VALUES REACHES THE N/MT/FOOTHILL AND WRN NH ZONES MORE SO THAN ALONG THE COAST. THE AXIS OF THE HIGHEST 850 MB THETA E VALUES SURGES TO THE NE ACROSS THE ENTIRE FCST AREA ON SUNDAY AS THE LOW LVL FLOW FROM THE SFC TO 700 MB INCREASES ALONG WITH VEERING WINDS. THIS WILL INCREASE THE SHEAR TO ENHANCE TSTM ACTIVITY. SPC IS INDICATING A RISK OF TSTMS BEING STRONG TO MAYBE SVR. WILL PUT IN ENHANCE WORDING OF GUSTY WINDS, HEAVY RAIN AND SMALL HAIL WITH ANY TSTMS IN THE MID TO LATE AFTERNOON HOURS AWAY FROM THE COAST. THE INCREASING CLOUDS AND SCT SHRA/TSTMS WILL HOLD TEMPS BACK ON SUNDAY WITH HIGHS MOSTLY IN THE 70S WITH SOME LOWER 80S S. IF THERE IS MORE SUNSHINE THEN HIGHS COULD END UP BEING A BIT WARMER... ESPECIALLY AWAY FROM THE COAST. ALONG THE COAST ONSHORE S SW WINDS WILL HAVE A COOLING AFFECT...AND WILL ALSO OFFSET TSTM ACTIVITY ALONG THE COAST AS IS ALSO INDICATED BY FCST INSTABILITY PARAMETERS /CAPE AND LI/. SFC DEW POINTS WILL BE ON THE RISE... INTO THE 60S JUST ABOUT EVERYWHERE...WITH THE POTENTIAL OF REACHING 70. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... THE MODELS ARE IN GENERAL AGREEMENT ON THE LONGWAVE PATTERN WELL INTO NEXT WEEK. WE BEGIN THE PERIOD WITH A WEST-SOUTHWEST UPPER FLOW THAT INTRODUCES A BRIEF WARM UP ALONG WITH RISING HUMIDITY LEVELS...FOLLOWED QUICKLY BY AN EASTERN TROUGH AND COOLER UNSETTLED WEATHER. IN THE DAILIES...A WARM FRONT WILL CROSS THE AREA SUNDAY WITH A WARM HUMID AIRMASS TO FOLLOW FOR MONDAY AND TUESDAY IN ADVANCE OF A SLOW-MOVING COLD FRONT. THE COLD FRONT IS EXPECTED TO EXIT THE COAST BY LATE WEDNESDAY. HIGH PRESSURE WILL BUILD TO THE SOUTH OF THE AREA THURSDAY AND FRIDAY. && .AVIATION /10Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM /THROUGH SUNDAY/...VFR TODAY AND TNGT...EXCEPT PATCHY VALLEY F EARLY THIS MORNING MAY AFFECT LEB. AREAS OF F POSSIBLE TNGT WHICH MAY IMPACT TAF SITES LIKE LEB...HIE AND CON. LONG TERM... MON - TUE...IFR IN COASTAL AM FOG...OTHERWISE AREAS OF MVFR IN SHOWERS AND TSTMS. && .MARINE... SHORT TERM /TODAY THROUGH SUNDAY/...UPDATED TO INPUT LATEST OBSERVED DATA RESULTING IN NO REAL CHANGES TO THE PREVIOUS FCST. HIGH PRESSURE MOVING OFFSHORE TODAY WITH A WARM FNT PUSHING NE INTO THE REGION TNGT. S SW FLOW ENHANCED BY A SEA BREEZE TODAY. STILL EXPECT WINDS/SEAS BELOW SCA LEVELS. THE S SW FLOW INCREASES SUNDAY AS THE WARM FNT MOVES TO THE NE AND THE SFC PRESSURE GRADIENT INCREASES. WIND GUSTS MAY REACH MINIMAL SCA LEVELS OVER THE OPEN WATERS. THIS WILL FORCE SEAS TO BUILD...AND THEY MAY ALSO REACH SCA LEVELS SUNDAY AFTERNOON OVER THE OPEN WATERS. LONG TERM... MON - TUE...SMALL CRAFT WINDS AND SEAS ARE POSSIBLE. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...NONE. NH...NONE. MARINE...NONE. && $$

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