062
FXUS61 KGYX 180622
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
222 AM EDT SAT APR 18 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES NEEDED WITH THIS FORECAST PACKAGE AS
RAINFALL AND SNOWFALL TRENDS HAVE HELD STEADY FOR SUNDAY.
KEY MESSAGES
1. ONSHORE FLOW DEVELOPS TODAY BRINGING COOL TEMPERATURES AND
FOG, POSSIBLY DENSE, INTO THE FORECAST. HIGH ASTRONOMICAL TIDES
COMBINED WITH SOME SURGE MAY BRING WATER LEVELS NEAR MINOR FLOOD
STAGE DURING TONIGHT'S HIGH TIDE CYCLE.
2. WIDESPREAD RAIN, BRIEFLY HEAVY AT TIMES, ON SUNDAY WILL
TRANSITION TO LIGHT SNOW SHOWERS SUNDAY NIGHT. LIGHT SNOW
ACCUMULATIONS POSSIBLE ACROSS THE MOUNTAINS AND FAR NORTH.
3. COOL AND DRY CONDITIONS FOR THE MAJORITY OF NEXT WEEK, BUT THE
PATTERN REMAINS SOMEWHAT UNSETTLED.
DISCUSSION
KEY MESSAGE 1 DESCRIPTION...
VERTICALLY STACKED LOW PRESSURE DEVELOPS OFFSHORE TODAY WHICH
WILL START A FEED A COOLER MOIST AIR INTO THE REGION. HOWEVER
HIGH PRESSURE STAYS NOSED IN THROUGH AT LEAST THE AFTERNOON
KEEPING THE AREA MOSTLY DRY. TEMPERATURES ONLY TOP OUT IN THE
50S AS CLOUDS BECOME ABUNDANT SOUTH OF THE MOUNTAINS. AS THIS
MOIST FLOW CONTINUES SATURDAY NIGHT DENSE MARINE FOG WILL PUSH
ONSHORE, WITH DRIZZLE AND PATCHY FOG MAKING IT INLAND AS WELL AS
THE COLUMN CONTINUES TO MOISTEN. TEMPERATURES FALL INTO THE
UPPER 30S AND LOW 40S.
LOOKING AT COASTAL FLOOD GUIDANCE THERE IS SOME SUGGESTION THAT WITH
THIS LOW IN THE POSITION SOUTH OF THE GULF OF MAINE SATURDAY NIGHT,
WE COULD SEE AROUND A HALF FOOT OF SURGE WHICH COMBINED WITH THE
11.3 ASTROTIDE COULD BRING AREAS FROM PORTLAND SOUTH NEAR THEIR
MINOR FLOOD STAGES DURING THE SATURDAY NIGHT HIGH TIDE CYCLE. THIS
FLOOD GUIDANCE HAS SEEMED TO RUN HOT DURING RECENT EVENTS SO MY
CURRENT THINKING IS THAT WE WOULDN'T QUITE GET THERE, BUT SINCE
THERE IS STILL TIME I WILL LET THE NEXT SHIFT REVIEW SUBSEQUENT
GUIDANCE CYCLES AND MAKE A DECISION IF A PRODUCT IS NECESSARY.
KEY MESSAGE 2 DESCRIPTION...
LOW PRESSURE TRACKS JUST TO OUR SOUTHEAST ON SUNDAY AS A COLD
FRONT IS PROGGED TO MOVE THROUGH THE AREA. THIS COMBINATION
BRINGS WIDESPREAD RAINFALL TO MANY LOCATIONS. EVEN THOUGH
CONVECTION WON'T BE MUCH OF A FACTOR ALL THIS AFOREMENTIONED
ONSHORE FLOW IS GOING TO SURGE PWATS INTO THE 1-1.25" RANGE, SO
I WOULD ANTICIPATE EMBEDDED HEAVIER SHOWERS DEVELOPING WITHIN
THE LIGHTER STRATIFORM BAND. THE QPF TREND HAS BEEN HOLDING
STEADY WITH AMOUNTS GENERALLY IN THE 0.25-0.75 INCH RANGE, WITH
LOCALLY HIGHER AMOUNTS IN THE MOUNTAINS WHERE UPSLOPE SNOW WILL
BE CONTRIBUTING. SPEAKING OF THIS, RAIN SHOWERS WILL BE
TRANSITIONING TO SNOW SHOWERS FROM NORTHWEST TO SOUTHEAST
BEGINNING SUNDAY AFTERNOON AS COLD AIR RAPIDLY MOVES IN BEHIND
THE FRONT. THE TOTALS ARE GOING TO BE HIGHER IN THE MOUNTAINS
AND NEAR THE INTERNATIONAL BORDER, BUT WITH ABOUT HALF OF THE
EVENT OCCURING EARLY ENOUGH THAT SURFACE TEMPERATURES WON'T BE
CONDUCIVE TO ACCUMULATION A SLUSHY 1-2 INCHES IS ABOUT ALL IT IS
GOING TO AMOUNT TO, WITH LOCALLY HIGHER AMOUNTS NEAR 3 INCHES
AT HIGHER ELEVATIONS. BY THE TIME ANY SNOW SHOWERS GET SOUTH OF
THE MOUNTAINS SUNDAY NIGHT, FORCING WILL BE WEAKENING AS
RIDGING BEGINS TO BUILD ALOFT. THIS COMBINED WITH SURFACE
TEMPERATURES STILL ABOVE FREEZING MEANS ACCUMULATION IN THESE
LOCATIONS IS NOT LIKELY. SOME STRAY SHOWERS MAY LINGER INTO THE
LATER HOURS SUNDAY, BUT WITH THE AFOREMENTIONED HEIGHT RISES
ALOFT AND HIGH PRESSURE BEGINNING TO NOSE IN AT THE SURFACE, IT
LOOKS LIKE THE AREA COULD BE MOSTLY DRY NOT LONG AFTER SUNSET.
KEY MESSAGE 3 DESCRIPTION...
THE UPPER-LEVEL TROUGH THAT BRINGS SUNDAY'S PRECIPITATION CHANCES
WILL STALL OUT OVERHEAD FOR MOST OF NEXT WEEK DUE TO DOWNSTREAM
RIDGING OVER THE NORTHERN ATLANTIC. IT WILL BE QUITE COLD ALOFT
INITIALLY WITH 850 MB TEMPERATURE ANOMALIES PEAKING AT 10C
BELOW CLIMATOLOGY, BUT A MODERATING TREND IS EXPECTED DEEPER
INTO NEXT WEEK. ON FACE VALUE THERE IS A SIGNAL FOR COOLER THAN
NORMAL SURFACE TEMPERATURES, WHICH IS IN THE FORECAST.
MONDAY AND TUESDAY BOTH LOOK CHILLY BUT BRIGHT WITH HIGHS LARGELY IN
THE 40S OUTSIDE OF THE MOUNTAINS. A MODERATING TREND WILL COMMENCE
FOR THE SECOND HALF OF THE WEEK OWING TO HEIGHT RISES ALOFT AS THE
TROUGH FINALLY MOVES OUT. THE PATTERN GENERALLY LOOKS DRIER THAN
PREVIOUSLY THOUGHT, OWING TO PREVAILING WESTERLY FLOW, WHICH WILL
KEEP THINGS QUITE DRY DESPITE UPPER LEVEL TROUGHING. THERE MAY BE
CLOUDS AND ISOLATED PRECIPITATION IN THE MOUNTAINS WITH AN UPSLOPE
WIND COMPONENT. ONE CHANCE FOR MORE WIDESPREAD PRECIPITATION IS ON
WEDNESDAY, BUT OVERALL A WEAK SIGNAL AT THIS RANGE WITH
PROBABILITIES GENERALLY 20-50% OF MEASURABLE PRECIPITATION AT THIS
RANGE. GIVEN THE COLD AIRMASS, THERE IS A CHANCE OF SNOWFLAKES IF
ANY PRECIPITATION CHANCE COMES TO FRUITION.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
THROUGH 06Z SUNDAY...MARINE FOG WILL BE PUSHING INTO COASTAL
TERMINALS TO START THE TAF PERIOD WITH LOW CEILINGS AND POSSIBLY
SOME PATCHY FOG MAKING IT INLAND TO AUG, MHT, AND CON. IFR
CONDITIONS SEEM LIKELY BY 09Z. HIE AND LEB ARE EXPECTED TO
REMAIN GENERALLY VFR WITH LEB POTENTIALLY SEEING BRIEF MVFR AS
IT ENDS UP JUST ON THE OUTSKIRTS OF THE MARINE LAYER. THESE
RESTRICTIONS CONTINUE TO AROUND 15Z WHEN TERMINALS SHOULD SEE
IMPROVEMENT TO AT LEAST MVFR FOR THE AFTERNOON, WITH SOME EVEN
BRIEFLY SCATTERING TO VFR FOR AN HOUR OR TWO. HOWEVER, THIS WILL
BE SHORT LIVED AS AFTER 20Z CONDITIONS LOOK TO GO DOWNHILL
AGAIN RETURNING TERMINALS TO IFR. DENSE FOG DEVELOPING SEEMS
LIKE A GOOD BET AFTER 00Z SUNDAY, ESPECIALLY AT COASTAL
TERMINALS.
OUTLOOK...
REST OF SATURDAY NIGHT: IFR TO LIFR CONDITIONS IN LOW
CEILINGS AND DENSE FOG.
SUNDAY: SOME IMPROVEMENT TO CEILINGS AND VISIBILITIES AS RAIN ENTERS
THE REGION, BUT ONLY MVFR AT BEST. RAIN TRANSITIONS TO LIGHT SNOW
SHOWERS SUNDAY EVENING.
SUNDAY NIGHT: PRECIPITATION TAPERS OFF AND DRIER AIR MOVES IN
RAPIDLY IMPROVING CONDITIONS TO VFR.
MONDAY: LARGELY VFR CONDITIONS WITH NW WINDS AT 10-15 KTS DURING THE
DAYTIME BEFORE BECOMING LIGHT AND VARIABLE AT NIGHT. MVFR OR LOWER
POSSIBLE ONLY AT HIE.
TUESDAY: VFR CONDITIONS WITH LIGHT WINDS. LOWERING CEILINGS POSSIBLE
AT NIGHT.
WEDNESDAY: PRECIPITATION IS POSSIBLE (20-50%), RESULTING IN MVFR OR
LOWER, OTHERWISE VFR CONDITIONS CONTINUE.
MARINE
CONDITIONS REMAIN GENERALLY BELOW SCA LEVELS IN THE COASTAL
WATERS THROUGH SUNDAY. LOW PRESSURE CROSSING EAST OF THE GULF OF
MAINE MAY BRING SOME 5FT SEAS IN BRIEFLY, BUT THIS MAY NOT
REQUIRE AN SCA AS SPATIAL EXTENT LOOKS MARGINAL. SIMILARLY, A
FEW WIND GUSTS AROUND 25 KNOTS ARE POSSIBLE SUNDAY NIGHT AS A
STRONG COLD FRONT CROSSES THE WATERS, BUT MAINLY IN THE AREA
BORDERING THE OUTER WATERS.
FROM MONDAY AFTERNOON ONWARD, WIND AND SEAS WILL RELAX AND ARE
EXPECTED TO REMAIN BELOW SCA CRITERIA THROUGH THE PERIOD. HIGH
PRESSURE SHOULD THEN ALLOW CONDITIONS TO FALL BELOW SCA LEVELS BY
TUESDAY. THE ONLY POSSIBLE EXCEPTION IS ON WEDNESDAY WHERE HIGHER
WAVES ARE POSSIBLE WITH BRIEFLY UNSETTLED CONDITIONS.
GYX WATCHES/WARNINGS/ADVISORIES
ME...NONE.
NH...NONE.
MARINE...NONE.
DISCUSSION...BARKER/BARON
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