512
FXUS61 KGYX 181821
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
221 PM EDT TUE AUG 18 2026
WHAT HAS CHANGED
NO CHANGES WERE NECESSARY TO THE ONGOING FORECAST.
KEY MESSAGES
1. SOME INSTABILITY MAY LEAD TO AN ISOLATED SHOWER ACROSS THE
INTERIOR THIS AFTERNOON. THE NEXT FEW NIGHTS WILL BE FOGGY AND
WEDNESDAY SHOULD STAY MOSTLY DRY.
2. A WEAK BOUNDARY MAY BRING A FEW SHOWERS THURSDAY, BUT OTHERWISE
MOSTLY DRY CONDITIONS ARE FORECAST THROUGH AT LEAST THE FIRST
PART OF SATURDAY WITH SEASONABLE TEMPERATURES.
3. THE NEXT CHANCE FOR RAIN ON A WIDESPREAD BASIS ARRIVES FOR THE
SECOND HALF OF THE WEEKEND.
DISCUSSION
KEY MESSAGE 1 DESCRIPTION...
LOW PRESSURE JUST OFFSHORE OF CAPE COD WILL ALLOW FOR GLOOMY
CONDITIONS TO CONTINUE ACROSS NORTHERN NEW ENGLAND. A FEW ISOLATED
SHOWERS ARE CURRENTLY SEEN ACROSS WESTERN MAINE ON THE RADAR. VERY
STABLE MID-LEVELS SHOULD LIMIT CONVECTIVE ACTIVITY THIS AFTERNOON,
BUT RESIDUAL INSTABILITY COULD ALLOW FOR A FEW MORE ISOLATED SHOWERS
OR THUNDERSTORMS TO POP UP ACROSS THE INTERIOR THIS AFTERNOON.
TONIGHT, CALM CONDITIONS PERSIST ACROSS NH AND WESTERN MAINE, WITH
MARINE FOG AND LOW STRATUS ADVECTING INTO COASTAL AREAS. FOG WILL
DEVELOP WELL INTO THE INTERIOR, AND CONTINUE THROUGH WEDNESDAY
MORNING.
A FRONT WILL MOVE IN FROM THE GREAT LAKES ON WEDNESDAY, AND WILL
APPROACH NH BY WEDNESDAY EVENING. MOST PLACES SHOULD STAY DRY, BUT
AN STRAY SHOWER OR STORM COULD FORM AHEAD OF THE FRONT. THE STORMS
ATTACHED TO THE COLD FRONT ITSELF WILL PROBABLY BE DEAD ON ARRIVAL
AS CAMS SHOW A DECAYING TREND IN THE STORMS WHEN THEY ARE OVER NEW
YORK STATE. IN ADDITION, THE FRONT MOST LIKELY WON'T CROSS INTO THE
REGION UNTIL AFTER SUNSET SO THERE WON'T BE MUCH ENERGY TO WORK WITH
EITHER. PATCHY FOG RETURNS WEDNESDAY NIGHT AND WILL CONTINUE THROUGH
THURSDAY MORNING.
KEY MESSAGE 2 DESCRIPTION...
THERE ARE A COUPLE OF FEATURES THAT MAY BRING A FEW SHOWERS TO THE
REGION ON THURSDAY. THE FIRST IS A WEAK FRONTAL BOUNDARY CROSSING
THROUGH THE DAY WHILE THE SECOND IS A SHORTWAVE CROSSING SOUTHERN
NEW ENGLAND THAT COULD BRING AN ADDITIONAL COUPLE OF SHOWERS ALONG
THE COAST AND SOUTHERN NH. MOST WILL PROBABLY NOT SEE ANY RAIN BUT
THOSE THAT DO WILL ONLY SEE LIGHT AMOUNTS AS QPF SIGNALS IN THE
MODEL GUIDANCE IS LIMITED TO ONLY A FEW HUNDREDTHS. OTHERWISE,
SEASONAL TEMPERATURES ARE EXPECTED WITH HIGHS IN THE MID 70S TO LOW
80S.
HIGH PRESSURE THEN BUILDS IN FRIDAY AND THE FIRST PART OF SATURDAY,
KEEPING THE WEATHER DRY FOR MUCH OF THE AREA. THE HIGH DOES MOVE
OFF TO THE NORTHEAST LATER SATURDAY AS LOW PRESSURE EMERGES OFF
THE MID-ATLANTIC COAST, AND MOISTURE WILL START TO INCREASE FROM
SOUTH TO NORTH OVER NORTHERN NEW ENGLAND, POTENTIALLY ENOUGH
FOR A FEW SHOWERS ALONG THE COAST AND SOUTHERN NH DURING THE DAY
SATURDAY. BUT AGAIN, MOST WILL BE DRY AS THE BETTER CHANCES
HOLD OFF UNTIL THE SECOND HALF OF THE WEEKEND. HIGHS WILL IN THE
70S TO LOW 80S AND LOWS MOSTLY IN THE 50S, EXCEPT SOME EMBEDDED
UPPER 40S.
KEY MESSAGE 3 DESCRIPTION...
THIS INITIAL LOW WILL KEEP A CHANCE FOR SHOWERS ALONG THE COAST AND
SOUTHERN NH SATURDAY NIGHT, BUT RAIN CHANCES FURTHER INCREASE
AREAWIDE SUNDAY INTO SUNDAY NIGHT AS A 500MB APPROACHES FROM
THE WEST AND ENCOMPASSES MUCH OF THE US EAST COAST. THERE'S A
STRONG SIGNAL IN THE ENSEMBLE FOR MOST OF THE AREA TO SEE
MEASURABLE RAIN, ALTHOUGH THERE ARE TIMING DIFFERENCES. IF THE
500 MB TROUGH REMAINS AN OPEN WAVE THE RAIN LOOKS MORE IN THE
SUNDAY-SUNDAY NIGHT TIMEFRAME, BUT IF IT CLOSES OFF, THEN A
SLOWER ONSET AND END WILL LIKELY BE THE RESULT, MAKING THE
HIGHER RAIN CHANCES MORE IN THE SUNDAY NIGHT AND MONDAY WINDOW.
BY TUESDAY, WE SHOULD SEE A RETURN TO DRIER CONDITIONS, EXCEPT
THERE MAY BE SOME UPSLOPE SHOWERS IN THE MOUNTAINS.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
VFR IS EXPECTED THIS AFTERNOON OUTSIDE OF ISOLATED SHOWERS THAT
DEVELOP ACROSS THE INTERIOR. CONDITIONS WILL SIGNIFICANTLY
DEGRADE THIS EVENING AS WIDESPREAD PATCHY FOG BUILDS ACROSS NH
AND MAINE. IFR AND PERHAPS SOME LIFR IS POSSIBLE TONIGHT IN
AREAS OF DENSER FOG. VISIBILITY SHOULD IMPROVE QUICKLY
WEDNESDAY MORNING, BUT LOW CIGS WILL HANG ON THROUGH MUCH OF THE
FIRST HALF OF WEDNESDAY. CONDITIONS LOOK TO IMPROVE TO VFR BY
THE END OF THE DAY, BUT THIS PERIOD OF VFR WILL BE SHORT LIVED
AS FOG REDEVELOPS OVER THE AREA WEDNESDAY NIGHT. IFR IS EXPECTED
WITH FOG ON WEDNESDAY NIGHT AND WILL NOT IMPROVE UNTIL AFTER
SUNRISE ON THURSDAY.
OUTLOOK:
THURSDAY: A FEW SHOWERS IN THE AFTERNOON COULD PRODUCE BRIEF
INSTANCES OF MVFR, BUT OTHERWISE VFR.
THURSDAY NIGHT-SATURDAY: MAINLY VFR, EXCEPT NIGHTTIME/EARLY
MORNING VALLEY FOG COULD PRODUCE IFR TO LIFR AT HIE AND LEB.
SATURDAY NIGHT-SUNDAY: INCREASING CHANCES FOR RAIN. IFR TO MVFR
POSSIBLE.
MARINE
WINDS AND SEAS GENERALLY STAY BELOW SCA LEVELS. WINDS WILL BE LIGHT
AND VARIABLE THROUGH THE END OF THE WEEK. A BRIEF WINDOW OF ELEVATED
SEAS ARE POSSIBLE LATE TONIGHT, BUT THE HIGHER SEAS WILL LIKELY BE
CONFINED TO THE OPEN WATERS OFFSHORE FROM PENOBSCOT BAY. SEAS RECEDE
ON WEDNESDAY. OUTSIDE OF THIS WINDOW, SEAS OF 2-4FT ARE EXPECTED
THROUGH THE REST OF THE WEEK.
THURSDAY-TUESDAY...SCA CONDITIONS ARE CURRENTLY NOT EXPECTED
THROUGH EARLY NEXT WEEK. A WEAK FRONT CROSSES THE WATERS
THURSDAY AND WILL BE FOLLOWED BY HIGH PRESSURE BUILDING IN
FRIDAY AND THE START OF THE WEEKEND. THE HIGH SHIFTS TO THE
NORTH AND EAST AS A COUPLE OF LOW PRESSURES APPROACH AND CROSS
THE WATERS FROM THE WEST AND SOUTHWEST DURING THE LATE SATURDAY
THROUGH MONDAY TIMEFRAME. HIGH PRESSURE RETURNS BY TUESDAY OF
NEXT WEEK.
GYX WATCHES/WARNINGS/ADVISORIES
ME...NONE.
NH...NONE.
MARINE...NONE.
DISCUSSION...PALMER/COMBS
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