Area Forecast Discussion
Issued by NWS Portland, ME

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000
FXUS61 KGYX 221308
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
908 AM EDT TUE JUL 22 2014

.SYNOPSIS...
HIGH PRESSURE CENTERED TO OUR SOUTH WILL TRANSPORT INCREASINGLY
HOT AND HUMID AIR INTO THE AREA THROUGH WEDNESDAY. A COLD FRONT
WILL APPROACH LATE WEDNESDAY AND BRING SHOWERS AND STRONG THUNDERSTORMS.
THE FRONT MOVES ACROSS THE REGION WEDNESDAY NIGHT AND EXITS OFFSHORE
THURSDAY MORNING. HIGH PRESSURE BUILDS IN FROM THE WEST FRIDAY AND
SATURDAY. A WARM FRONT WILL APPROACH FROM THE SOUTHWEST LATE SUNDAY
AND MONDAY.

&&

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

905 AM...QUIET WEATHER WITH HIGH PRESSURE BUILDING BY TO OUR
SOUTH. I MADE MINOR ADJUSTMENTS FOR THIS ESTF UPDATE TO 1ST PERIOD
GRIDS THAT REFLECT THE MESONET. HAV A GUD DAY.

PREV DISC...
640 AM...JUST SOME ADJUSTMENTS TO T/TD/SKY FOR THE NEXT FEW
HOURS...BUT ALL IN ALL THE FORECAST FOR A WARM AND MAINLY SUNNY
DAY WITH INCREASING HUMIDITY HOLDS.

PREVIOUSLY...AFTER SOME MORNING FOG...RIDGING BUILDS AT MID AND
AND UPPER LEVELS TODAY AS SFC HIGHS SHIFTS JUST TO OUR SE. THIS
WILL BRING IN THE WARMER AIR AROUND 850 MB...AND SW FLOW WILL INCR
BRINGING IN THE MORE HUMID SFC AIR. HIGHS SHOULD CLIMB INTO THE
MID TO UPPER 80S INLAND AREAS...WITH TDS REACHING INTO THE MID TO
UPPER 60S BY LATE IN THE DAY. COASTAL ZONES SHOULD MAKE IT INTO
THE LOWERS 80...ALTHOUGH THE BEACHES AND THE MID-COAST MAY BE
LIMITED TO THE MID TO UPPER 70S. ALSO...SOME OF THE BEACHES MAY BE
LOOKING AT FOG BANK SITTING JUST OFFSHORE...ALTHOUGH THINK IT
SHOULD STAY OFFSHORE TODAY.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
THE INCREASING TDS AND SW GRADIENT FLOWN WILL MAKE FOR A WARM AND
HUMID NIGHT WITH LOWS GENERALLY IN THE MID TO UPPER
60S...ALTHOUGH MAYBE A LITTLE COOLER IN THE MTNS. VLY FOG SHOULD
BE COMMON...AND WILL HAVE TO WATCH FOR FOG/STRATUS WORKING ONSHORE
AGAIN...ESPECIALLY ALONG THE MID-COAST.

WED SHOULD START OFF WITH ANOTHER ROUND OF FOG...BUT THE SW FLOW
SHOULD MIX IT OUT FAIRLY EASILY. VERY WARM AIR AT 850 MB /15-17C/
WILL BE IN PLACE IN THE MORNING...AND IT SHOULD MIX DOWN AND WARM
THINGS UP QUICKLY WITH MOSTLY SUNNY SKIES OUTSIDE OF THE
MTNS....WHERE SOME MID-HIGH CLOUDS WILL MOVE IN DURING THE MORNING
MAKING IT MORE P/SUNNY. HIGHS SHOULD CLIMB A COUPLE WARMER THAN
TUESDAY...AND SHOULD REACH AROUND 90 IN THE WARMER SPOTS OF SRN NH
AND SW ME. COASTAL AREAS WILL BE ABOUT 3-5F COOLER.

WED AFT/EVE ARE STARTING TO COME TOGETHER FOR A ROUND OF SEVERE
STORMS AS THE WARM AND HUMID AIR GENERATES QUITE OF BIT OF
INSTABILITY /CAPES IN THE 1K-2K RANGE/ BY MIDDAY INTO THE
AFTERNOON. PRE-FRONTAL TROUGH SWINGS THROUGH BETWEEN 18-00Z AS
500MB TROUGH OUTPACES THE ACTUAL SFC FRONT...ALLOWING FOR DECENT
FALL WHICH WILL ERODE THE MID-LVL CAP. ALL THIS IS DECENT FOR
PRODUCING SEVERE STORMS IN NRN NEW ENGLAND. TWO ISSUES ARE WIND
PROFILES...WHICH LIMIT BULK SHEAR TO AROUND 30 KTS OR SO...AND MID
LVL LAPSE RATES...WHICH ARE 5-7 C/KM. STILL...CONFIDENCE IS HIGH
THAT THERE WILL BE AT LEAST A FEW SEVERE STORMS...MOSTLY
PRODUCING STRONG OR DAMAGING WINDS...ALTHOUGH LARGE HAIL CANNOT BE
RULED OUT. THE STORMS MAY NOT MOVE INTO COASTAL ZONES UNTIL EARLY
EVE...AND COULD SEE MARINE LYR WEAKEN THE STORMS BEFORE THEY GET
THERE.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
MODELS ARE SIMILAR IN MOVING A COLD FRONT OFF THE COAST EARLY
THURSDAY MORNING. USHERING IN DRIER AND MORE COMFORTABLE AIR.
THUNDERSTORMS WILL LINGER INTO WEDNESDAY NIGHT AHEAD OF THE COLD
FRONT. SOME THUNDERSTORMS COULD REACH SEVERE LEVELS. ACTIVITY WILL
DECREASE AS WE LOSE THE HEATING OF THE DAY. HIGH PRESSURE WILL
BUILD OVER THE AREA THURSDAY AFTERNOON THROUGH SATURDAY. MODELS
ARE INDICATING THAT A WEAK FRONT WILL TOUCH THE NORTHERN PORTIONS
OF THE FORECAST AREA LATE FRIDAY OR SATURDAY. CAN/T RULE OUT A
BRIEF SHOWER IN THE MOUNTAINS FRIDAY AFTERNOON OR SATURDAY AFTERNOON
DEPENDING ON THE EXACT TIMING OF THE FEATURE. THE GFS BRINGS THIS
FEATURE THROUGH EARLIER THAN THE ECMWF. WARMER AN MORE HUMID
WEATHER RETURNS ON SUNDAY AND MONDAY AS WINDS TURN TO THE
SOUTHWEST.

&&

.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
SHORT TERM...EXPECTING ANOTHER ROUND OF VLY FOG FOR A COUPLE HOURS
AROUND SUNRISE THIS MORNING. HAVE SEEN SOME FG/STRATUS AT
KRKD...BUT THIS LOOKS TO BE LOCAL EFFECT AS BULK OF FOG BANK STILL
HOLDING WELL OFFSHORE BASED ON 11-3.9 MU SAT PRODUCT. VFR WILL
RETURN BY 12-13Z AT ALL TERMINALS. MORE FLIGHT RESTRICTIONS IN
FOG/STRATUS AGAIN TONIGHT....ESPECIALLY INLAND VLYS. WED WILL SEE
A RETURN TO VFR IN THE MORNING...BUT SEVER TSRA ARE POSSIBLE AT
INLAND TERMINALS BY MID-LATE AFTERNOON.

LONG TERM...EXPECT MOSTLY VFR EXCEPT MVFR/IFR WEDNESDAY NIGHT IN
SHOWERS AND THUNDERSTORMS. VFR FRIDAY AND SATURDAY.

&&

.MARINE...
SHORT TERM...MAIN FOG BANK LOOKS TO SIT OVER THE OUTER WATERS
TODAY...ALTHOUGH SOME PATCHES OF FOG WILL BE POSSIBLE AWAY FROM
THE SHORE. SW WINDS WILL BEGIN TO PICK UP THIS AFTERNOON...WITH
SEAS FOLLOWING TONIGHT. MAY NEED SCA FOR BORDERLINE/WINDS SEAS ON
WED.

LONG TERM...SCA MAY BE NEEDED WEDNESDAY NIGHT PRIOR TO COLD
FRONTAL PASSAGE. SCA MAY BE NEEDED SUNDAY AND MONDAY.

&&

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

&&

$$
ES





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