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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KGYX 211605
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
1205 PM EDT MON JUL 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD TO OUR SOUTH THROUGH TUESDAY. WE`LL
BECOME PROGRESSIVE WARMER AND MORE HUMID THROUGH WEDNESDAY AHEAD
OF AN APPROACHING COLD FRONT. THE COLD FRONT WILL APPROACH LATE
WEDNESDAY AND BRING A CHANCE OF SHOWERS AND THUNDERSTORMS. THE
FRONT MOVES ACROSS THE REGION WEDNESDAY NIGHT AND EXITS OFFSHORE
THURSDAY MORNING. HIGH PRESSURE BUILDS IN FROM THE WEST FRIDAY AND
SATURDAY.

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...

1200 PM...ONLY MINOR ADJUSTMENT TO 1ST PERIOD GRIDS FOR THIS ESTF UPDATE.

940 AM...QUIET DAY WITH HIGH PRESSURE IN CONTROL. I MADE
ADJUSTMENTS TO 1ST PERIOD GRIDS TO REFLECT CURRENT MESONET FOR
THIS ESTF UPDATE.

PREV DISC...
625 AM...JUST SOME TWEAKS OF T/TD/SKY BASED ON CURRENT
OBS...OTHERWISE FORECAST REMAINS UNCHANGED FOR TODAY WITH ONSHORE
FLOW KEEPING THE COAST COOL...AND THE RISK OF A SHOWER OR TWO IN
THE MTNS.

PREVIOUSLY...THE WEAK OCEAN LOW WILL SLIDE WELL TO OUR S AND E
THIS MORNING... AND SURFACE HIGH...CENTERED TO OUR S...BEGINS TO
BUILD. THIS SHOULD ALLOW FOR A AN ONSHORE FLOW TO DEVELOP...AS
WEAK ONSHORE PGF DEVELOPS POLEWARD OF THE RIDGE. MAXES SHOULD BE
CLOSE TO NORMAL INLAND AREAS...AROUND 80...ALTHOUGH GIVEN THE
ONSHORE FLOW COASTAL AREAS WILL BE STUCK IN THE LOW TO MID 70S.

NAM CONTINUES TO PRODUCE SOME POPS OVER THE MOUNTAINS...WHILE ALL
OTHER MODELS KEEP THINGS DRY. NOT SURE IF ITS PICKING UP ON WEAK
UPSLOPE EASTERLY FLOW...OR THE LINGERING WEAK TROUGH AT 500
MB...OR A COMBINATION OF BOTH...BUT WITH DEW POINTS ON THE RISE
AND SOME INSTABILITY IN PLACE...FEEL THAT POPS OF 15-20 FOR A
FEW HOURS DURING PEAK HEATING ARE WARRANTED.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH 6 PM TUESDAY/...
WE START TO TO SEE THE W-SW FLOW BEGIN TO PICK UP A BIT IN THE
BOUNDARY LAYER TONIGHT AS THE HIGH BEGINS TO BUILD MORE TO OUR SE
THAN S...HELPING TO PUSH DEW POINTS UP A BIT...AND GENERALLY
LIMITING THE BEST RADIATIONAL COOLING...SO MINS NOT AS COLD AS
THIS MORNING...BUT STILL IN THE 50S TO AROUND 60. SHOULD SEE
ANOTHER ROUND OF VALLEY FOG...AS WE SEE INCREASING DEW POINTS...
BUT ALSO MORE FLOW IN THE BOUNDARY LAYER. STILL QUESTIONS ARISE AS
TO COASTAL STRATUS/FOG...BUT MODELS SUGGESTING IF IT DOES OCCUR
LOOKS TO BE AFTER SUNSET...WITH BETTER CHANCE ALONG THE MID-
COAST. HAVE THROWN SOME PARTLY CLOUDY CONDITIONS IN ON THE COAST
FOR NOW.

ON TUESDAY...WILL SE THAT VERY ARM MID LEVEL AIR ADVECTING IN FROM
THE WSW...GENERALLY REACHING 15-17C...WHICH WILL TRANSLATE INTO THE
HIGHS INTO THE MID-UPPER 80S ACROSS INLAND AREAS. DEW POINTS WILL
CREEP UP INTO THE MID TO UPPER 60S BY AFTERNOON...SO IT WILL BE
NOTICEABLY MORE HUMID AS WELL. SYNOPTIC FLOW SHIFTS TO SW BY
TUESDAY AFTERNOON...AND THIS WILL TURN ONSHORE ALONG THE E
FACING COASTS...KEEPING THEM A FEW DEGREES COOLER...WHILE THE MID-
COAST WILL MAX OUT IN THE MID 70S TO AROUND 80. MODELS SUGGESTING
SOME PRECIPITATION DEVELOPS VICINITY OF NH/MA BORDER TUESDAY AFTERNOON...
MAYBE ON SEA BREEZE BOUNDARY.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
WITH MORE MOISTURE AROUND... TUESDAY NIGHT WILL BE A MORE HUMID
NIGHT WITH LOWS IN THE 60S. ON WEDNESDAY... THE UPPER RIDGE AXIS
MOVES EAST OF THE AREA AND IS REPLACED BY A TROUGH MOVING IN FROM
THE NORTHWEST. SURFACE COLD FRONT WILL ALSO PUSH SOUTHEAST ACROSS
THE AREA ON WEDNESDAY... LIKELY REACHING THE COAST BY WEDNESDAY
EVENING. MODELS ARE IN BETTER AGREEMENT ON THE TIMING OF THIS
FRONT NOW.

TEMPERATURES WEDNESDAY WILL BE WARMER THAN WE HAVE SEEN IN A
WHILE. 850 MB TEMPERATURES WARM TO AROUND +18C WHICH IF MIXED DRY
ADIABATICALLY TO THE SURFACE WOULD TRANSLATE TO AROUND 90F FOR A
MAXIMUM TEMPERATURE. MOST LIKELY AREAS TO SEE 90 WILL BE IN
SOUTHEAST NEW HAMPSHIRE AND SOUTHWEST MAINE. SOUTHWEST FLOW AT THE
SURFACE WILL NOT BE ENOUGH TO KEEP THE SEA BREEZE AWAY FROM THE
COAST... SO COASTAL AREAS (ESPECIALLY FROM PORTLAND EASTWARD) WILL
BE SIGNIFICANTLY COOLER.

OF COURSE WITH ALL THE HEAT AND HUMIDITY AROUND ON WEDNESDAY...
THERE WILL ALSO BE PLENTY OF INSTABILITY. THAT WARM AIR ALOFT WILL
ACTUALLY SERVE AS A CAP TO PREVENT THUNDERSTORMS FROM DEVELOPING
INITIALLY. BUT THIS CAP WILL BE ERODED FROM THE BOTTOM AND THE TOP
AS THE DAY GOES ON... WITH WARMING SURFACE TEMPERATURES AND
COOLING TEMPERATURES ALOFT WITH THE APPROACHING TROUGH COMBINE TO
OVERCOME THE CAP AND ALLOW ACCESS TO THE INSTABILITY. THROW IN
SOME SURFACE CONVERGENCE ALONG THE FRONT AND LIFT AHEAD OF THE
UPPER TROUGH AND THERE SHOULD BE A FAIRLY WIDESPREAD COVERAGE OF
THUNDERSTORMS BY WEDNESDAY AFTERNOON. WILL LIKELY SEE STORMS FORM
INITIALLY OVER THE MOUNTAINS AND IN SOUTHERN CANADA BEFORE MOVING
SOUTHEAST DURING THE AFTERNOON. WIND PROFILES WILL AT LEAST BE
SUPPORTIVE OF MULTICELL THUNDERSTORMS AND THE ASSOCIATED
CONVECTIVE WIND THREAT. BUT THERE MAY ALSO BE ENOUGH SHEAR FOR
SOME SUPERCELL STRUCTURE... DEPENDING ON THE TIMING OF THE SURFACE
AND UPPER LEVEL FEATURES. HAVE INCLUDED GUSTY WINDS AND SMALL HAIL
IN THE FORECAST FOR WEDNESDAY AND HAVE MENTIONED POTENTIAL SEVERE
WEATHER IN THE HAZARDOUS WEATHER OUTLOOK.

THE FRONT WILL PUSH OFFSHORE ON WEDNESDAY NIGHT... DECREASING RAIN
CHANCES AS IT DOES SO. BY THURSDAY A DRIER AND COOLER AIR MASS
WILL BE MOVING IN WITH HIGH TEMPERATURES ABOUT 10 DEGREES COOLER
THAN WEDNESDAY.

UPPER TROUGH REMAINS OVER QUEBEC AND NEW ENGLAND FRIDAY AND
SATURDAY... SO CANNOT COMPLETELY RULE OUT A STRAY SHOWER. BUT THE
GENERAL TREND WILL BE DRY AND COOLER WITH HIGHS IN THE 70S TO NEAR
80 AND LOWS IN THE 50S TO NEAR 60.

&&

.AVIATION /16Z MONDAY THROUGH FRIDAY/...
SHORT TERM...SEEING VALLEY FOG DEVELOPING AT NON-TERMINAL SITES...
BUT NOTHING YET AT THE TERMINALS. EXPECT KHIE/KLEB TO SEE SOME
FOG/STRATUS BY SUNRISE...WITH SOME FOG POSSIBLE FOR AN HOUR OR TWO
AT KCON AND MAYBE KAUG. VFR EXPECTED THROUGH THE DAY TODAY.
ANOTHER ROUND OF VALLEY FOG TONIGHT...AND THERE IS THE POSSIBILITY
OF COASTAL FOG STRATUS DEVELOPING LATER THIS EVENING. ALL
TERMINALS RETURN TO VFR BY TUESDAY MORNING.

LONG TERM...EXPECT SHOWERS AND THUNDERSTORMS TO MOVE FROM
NORTHWEST TO SOUTHEAST ACROSS THE AREA WEDNESDAY AFTERNOON AND
EVENING. COULD SEE SOME FOG LATE WEDNESDAY NIGHT AFTER THE RAIN
MOVES THROUGH. VFR CONDITIONS EXPECTED THE REST OF THE WEEK WITH
THE USUAL CAVEATS ABOUT NOCTURNAL FOG AT LEB AND HIE.

&&

.MARINE...
SHORT TERM...LIGHT WINDS AND SEAS EXPECTED THROUGH TONIGHT....WITH
SEA BREEZE DEVELOPING THIS AFTERNOON. WILL START TO SEE WSW WINDS
INCREASE TUESDAY AFTERNOON...BUT STAYING BELOW SCA LEVELS.

LONG TERM...SOUTHWEST FLOW AHEAD OF THE FRONT ON WEDNESDAY WILL
PEAK AT 20 OR 25 KT... WITH WAVE HEIGHTS RISING TO 4 TO 5 FEET.
COLD FRONT SHOULD BRING THE STRONGER WINDS TO AN END WEDNESDAY
NIGHT AND WAVE HEIGHTS SUBSIDE THROUGH THE REST OF THE WEEK.

&&

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

&&

$$
ES