Area Forecast Discussion
Issued by NWS Portland, ME

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000
FXUS61 KGYX 220209
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
1009 PM EDT THU AUG 21 2014

.SYNOPSIS...
A WEAKENING DISTURBANCE FROM THE GREAT LAKES WILL PROVIDE THE
CHANCE FOR A FEW SHOWERS OVER NORTHERN AND WESTERN SECTIONS OF
OUR AREA THROUGH FRIDAY. OTHERWISE...A RIDGE OF HIGH PRESSURE WILL
ANCHOR OVER MAINE AND NEW HAMPSHIRE OVER THE WEEKEND AND EARLY
NEXT WEEK...WITH A GRADUAL WARMING TREND.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
10 PM UPDATE: NO ADDITIONAL CHANGES NEEDED ATTM. THE BAND OF RAIN
OVER SRN NH NOW MOVING INTO EXTREME SW MAINE. TIMING AND FORECAST
AMTS FROM PREVIOUS UPDATES ON TARGET.  SOME SCT SHWRS
ELSWHERE ACROSS THE FA CONTINUE AS WELL.

705 PM UPDATE: MADE FURTHER ADJUSTMENTS FOR TNGT AND INTO EARLY
FRI FOR ALL OF THE SOUTHERN HALF OF NH INTO XTRM SW MAINE. GOING
WITH CATEGORICAL POPS AND .5-1.0 INCHES OF QPF BY 12Z FRI. FURTHER
N+E POPS AND QPF WILL DROP OFF DRAMATICALLY. FOR FRI WITH UPPER
LOW OVER HEAD CREATING DIURNAL STEEP LAPSE RATES EXPECT SCT
CONVECTION TO DEVELOP OVER THE ENTIRE FA.

510 PM UPDATE: MADE MAJOR ADJUSTMENTS TO FORECAST FOR POPS/WX NOW
AND THROUGH THE REST OF THE NIGHT TO REFLECT WIDESPREAD SHWR
ACTIVITY. INCREASED THE POPS ACROSS THE FA AND INCREASED QPF. SOME
AREAS IN NH MAY SEE A GOOD SHOT OF QPF IN THE SHWRS LATE TONIGHT
WHILE MAINE PORTIONS QPF AMTS WILL REMAIN LIGHT. MORE SCT
CONVECTIONS IS EXPECTED FRI. ADJUSTMENTS FOR FRI WILL BE UPDATED
ON THE NEXT UPDATE.

PREV DISC: BAND OF PRECIP THAT CROSSED SW ME...AND
BROUGHT SOME MODERATE RAFL...HAS MOVED NE AND WEAKENED. THIS WAS
SET OFF BY SOME BRIEF MID-LVL FRONTOGENESIS. ALSO...SEEING SOME
CONVECTION DEVELOP ALONG SFC TD BOUNDARY IN THE ERN ZONES...WHERE
THERE HAS BEEN MORE SUN AND HEATING. THESE SHOULD TRACK NNW ALONG
THE BOUNDARY AND DIMINISH WITH DAYTIME HEATING.

FOR TONIGHT...COULD SEE ANOTHER ROUND OF SHRA MOVE INTO SRN AND
WRN NH THIS EVENING...BUT THESE SHOULD DIMINISH AS THEY HEAD EWD
TOWARD ME...WITH LITTLE CHC OF ANY PRECIP LATE TONIGHT. CLOUDS
AND MARINE AIR WILL KEEP MINS INTO THE UPPER 50S TO LOWER 50S ON
THE COASTAL PLAIN...AND COULD SEE SOME MID 50 READINGS IN THE
MTNS.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
ON FRIDAY...LOOK FOR A WEAK 500 MB WAVE TO ALLOW A PUSH OF COOLER
AIR IN FROM THE NE...WHICH COULD SET OFF OF SCT SHRA....ESPECIALLY
IN THE MTNS. GRADIENT FLOW WILL SHIFT TO EAST AND DEEPEN A
BIT...SO IT WILL BE CLOUDY AND COOL...WITH HIGHS ONLY IN THE
UPPER 60S OR LOW 70S.

EXPECT AT LEAST PARTIAL CLEARING FRI NIGHT WITH MINS GENERALLY IN
THE 50S ONCE AGAIN.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
BOUNDARY EVENTUALLY PUSHES SWD THRU THE REGION ON SAT. AS IT DOES
SO A STEADY CLEARING WILL WORK IN FROM N TO S. IF BOUNDARY HANGS
UP IN SRN NH...THERE COULD BE A FEW SHOWERS THAT POP UP DURING
PEAK HEATING. OTHERWISE...HIGH PRES MOVES IN AND DOMINATES THE WX
THRU MIDWEEK. RIDGE AXIS ALOFT MOVES EWD...BUT WILL REMAIN JUST
OFF TO THE W. THIS WILL PREVENT THE SERIOUS HEAT FROM WORKING ALL
THE WAY EWD...BUT WILL ALLOW FOR A GRADUAL WARMING TREND. MODEL
GUIDANCE AGREES THAT FOR THE SECOND HALF OF THE WEEK A COLD FNT
WILL APPROACH FROM THE W. HOWEVER...ATTM THEY DISAGREE ON TIMING.
PREFER THE SLOWER TIMING AT THIS POINT...WITH A VERY BLOCKY
PATTERN IN PLACE.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
SHORT TERM...
705 PM UPDATE: AREAS OF MVFR/IFR CIGS IN SHWRS AND ISOLD TSTMS
OVERNIGHT WITH THE MOST PREVAILING LWR CIGS/VSBYS OVER THE SRN
HALF OF NH AND INTO XTRM SWRN MAINE.

PREV DISC:
COULD SEE A PERIOD OF MVFR TO IFR CIGS LATE
TONIGHT INTO FRIDAY MORNING...PERHAPS DROPPING TO LIFR AT
KLEB/KAUG...WITH IMPROVEMENT TO VFR FRI AFTERNOON.

LONG TERM...MOSTLY VFR CONDITIONS EXPECTED WITH MORNING FOG IN
FAVORED VALLEY LOCATIONS.

&&

.MARINE...
SHORT TERM...ALTHOUGH WE COULD SEE A SURGE OF NE WINDS TO AROUND
15 KTS ON FRIDAY...WINDS AND SEAS REMAIN BLO SCA LVLS THROUGH FRI
NIGHT.

LONG TERM...WINDS AND SEAS EXPECTED TO BE BELOW SMALL CRAFT
CRITERIA.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...
NEAR TERM...MARINE
SHORT TERM...MARINE
AVIATION...MARINE



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