072
FXUS61 KGYX 280650
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
250 AM EDT SUN JUN 28 2026
WHAT HAS CHANGED
A DENSE FOG ADVISORY HAS BEEN ISSUED THROUGH 8AM THIS MORNING
FOR THE COAST ALONG WITH PORTIONS OF INTERIOR WESTERN ME.
OTHERWISE, NO SIGNIFICANT CHANGES WITH THIS FORECAST UPDATE
WITH THE MAIN FOCUS BEING THE POTENTIAL FOR EXTREME HEAT BY THE
MIDDLE OF THE WEEK.
KEY MESSAGES
1. SEASONABLE TEMPERATURES CONTINUE TODAY WITH SCATTERED
SHOWERS AND ISOLATED STORMS THIS AFTERNOON.
2. HEAT AND HUMIDITY WILL BUILD THROUGH MID WEEK BRINGING THE
POTENTIAL FOR EXTREME HEAT WEDNESDAY AND THURSDAY FOR
INTERIOR/COASTAL MAINE AND THE SOUTHERN HALF OF NEW HAMPSHIRE.
PREPARE COOLING SYSTEMS EARLY THIS WEEK, AND IF PLANS INCLUDE
STRENUOUS OUTDOOR ACTIVITIES, CONSIDER RESCHEDULING FOR THE
MORNING WHEN HEAT ISN'T AS INTENSE.
DISCUSSION
KEY MESSAGE 1 DESCRIPTION...
CYCLONIC FLOW ALOFT WILL PERSIST THROUGH TODAY BEFORE THE TROUGH
AXIS MOVES EAST TONIGHT. SURFACE HEATING TODAY WILL AGAIN ALLOW
FOR AN AXIS OF SB CAPE TO BUILD AROUND 1000 J/KG AWAY FROM THE
COAST. THIS INSTABILITY COMBINED WITH THE CYCLONIC FLOW WILL ALLOW
FOR SHOWERS AND PERHAPS A FEW THUNDERSTORMS TO DEVELOP IN THE
AFTERNOON WHILE THE LACK OF ANY SURFACE FORCING WILL LIMIT
COVERAGE. DEEP LAYER SHEAR AROUND 40 KTS WOULD SUGGEST THAT A
STRONG THUNDERSTORM CANNOT BE RULED OUT. HIGH TEMPERATURES WILL
GENERALLY BE IN THE MID TO UPPER 70S ACROSS THE NORTH AND ALONG
THE COAST, AND LOW 80S ELSEWHERE.
SHOWERS AND ANY STORMS DISSIPATE THIS EVENING WITH THE LOSS OF
HEATING. A LIGHT WEST IS EXPECTED TONIGHT THAT WILL LIKELY LIMIT
ANY FOG TO VALLEY LOCATIONS.
KEY MESSAGE 2 DESCRIPTION...
BY SEVERAL INDICATORS ENSEMBLES CONTINUE TO PORTEND TO A PERIOD
OF EXTREME HEAT PUSHING INTO AT LEAST SOUTH-CENTRAL NEW HAMPSHIRE
AND SOUTHWEST MAINE WEDNESDAY AND THURSDAY WITH HOT AND HUMID
CONDITIONS POTENTIALLY LASTING INTO FRIDAY. ENSEMBLES SHOW
ANOMALOUS DEEP LAYER RIDGING EXCEEDING 99TH PERCENTILE AT 500
MB PRESSING INTO THE NORTHEAST WEDNESDAY AND THURSDAY. THIS
RIDGE WILL BE ACCOMPANIED BY ANOMALOUS MOISTURE AND HEAT WITH
850 MB TEMPERATURES ALSO AROUND THE 99TH PERCENTILE. THEREFORE,
CONFIDENCE REMAINS HIGH FOR A PERIOD OF CUMULATIVE HEAT STRESS
WEDNESDAY INTO FRIDAY WITH DAY TIME HEAT INDICES IN THE 100S
AND OVERNIGHT LOWS STRUGGLING TO DROP BELOW 70 DEGREES.
BEFORE THE HEAT AND OPPRESSIVE HUMIDITY ARRIVES, NORTHWEST FLOW
ALOFT AND HIGH PRESSURE WILL BRING FAIR WEATHER MONDAY. LOW
PRESSURE TRACKING ACROSS JAMES BAY WILL LIFT A WARM FRONT
THROUGH NORTHERN NEW ENGLAND LATE TUESDAY BRINGING INCREASING
CHANCES FOR SHOWERS AND STORMS THAT WILL PERSIST INTO TUESDAY
NIGHT. BEHIND THE WARM FRONT TEMPERATURES AT 850 MB WILL CLIMB
TO +20C TO +23C WEDNESDAY AND THURSDAY THAT WILL SUPPORT HOT
SURFACE TEMPERATURES IN THE MID 90S AND APPROACHING THE LOW 100S
THURSDAY. ALL THE WHILE, INCREASING MOISTURE WILL BRING DEW
POINTS TO OPPRESSIVE LEVELS INTO THE 70S. WINDS MAY HAVE A
STURDY ONSHORE COMPONENT WEDNESDAY THAT MAY ALLOW FOR SOME
RELIEF NEAR THE COAST. ON THURSDAY, STEADY WEST WINDS MAY KEEP
THE SEA BREEZE AT BAY ALLOW FOR HOT TEMPERATURES TO THE
COASTLINE. THE LATEST NBM CONTINUES THE HEAT AND HUMIDITY FRIDAY
WITH HIGHS IN THE UPPER 90S AND DEW POINTS IN THE 70S SO
PRECAUTIONS SHOULD BE TAKEN FOR A PROLONGED HEAT EVENT.
ENSEMBLES SUGGEST THE RIDGE WILL WEAKEN OR RETROGRADE WEST INTO
NEXT WEEKEND THAT WOULD ALLOW FOR THE EXTREME HEAT TO ABATE.
A FACTOR THAT MAY LIMIT TEMPERATURES FROM REALIZING THEIR FULL
POTENTIAL WILL BE ANY RIDGE ROLLING CONVECTION THAT BRINGS
CLOUDS AND CHANCES FOR SHOWERS AND STORMS. THERE IS A MODEST
SIGNAL FOR A REMNANT ELEVATED MIXED LAYER (EML) OVER THE UPPER
MIDWEST TO ROUND THE RIDGE AND BE IN THE VICINITY OF NORTHERN
NEW ENGLAND WEDNESDAY INTO WEDNESDAY NIGHT. WERE A REMNANT EML
MOVE ATOP THE HOT AND HUMID AIRMASS, CAPE WOULD BE ANOMOUSLY
HIGH FOR THIS PART OF THE COUNTRY AND WOULD SUPPORT SEVERE
STORMS. MACHINE LEARNING GUIDANCE OUT OF CSU HAS A RATHER ROBUST
SIGNAL FOR SEVERE STORMS WEDNESDAY AND THURSDAY WHILE ANY FINER
DETAILS WILL REMAIN UNCLEAR FOR A COUPLE MORE DAYS.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
THROUGH 06Z MONDAY: FOG AND LOW CEILINGS WILL RESULT IN IFR-LIFR
RESTRICTIONS THROUGH 12-14Z THIS MORNING, ESPECIALLY AT COASTAL
AND VALLEY TAF SITES. VFR CONDITIONS ARE THEN EXPECTED LATER
TODAY WITH LIGHT AND VARIABLE WINDS. A FEW SHRA ARE POSSIBLE
THIS AFTERNOON, PERHAPS BRINGING LOCALIZED BRIEF RESTRICTIONS.
ADDITIONAL FG IS POSSIBLE AGAIN TONIGHT, ALTHOUGH COVERAGE IS
EXPECTED TO BE LOWER.
OUTLOOK:
MONDAY: LOWER CEILINGS/VIS SHOULD CONSOLIDATE TO THE COASTAL
WATERS, WITH INLAND TERMINALS BECOMING VFR.
MONDAY NIGHT: RETURN OF LOWERED CEILINGS POSSIBLE OVERNIGHT FOR
COASTAL ME. MVFR TO IFR POSSIBLE.
TUESDAY AND TUESDAY NIGHT: IMPROVEMENT TO VFR IN THE MORNING,
BUT SHRA ARRIVE FROM THE WEST IN THE AFTERNOON, THESE MAY
CONTINUE INTO THE OVERNIGHT FOR ALL TERMINALS.
WEDNESDAY AND WEDNESDAY NIGHT: SHRA WITH SOME TS POSSIBLY
DEVELOP INLAND THROUGH THE AFTERNOON. THESE SHOULD REDUCE IN
COVERAGE OVERNIGHT.
MARINE
PATCHY DENSE FOG LINGERS THROUGH THE DAY TODAY, AND THEN
DISSIPATES WITH A WEST WIND TONIGHT. OTHERWISE, FAIR CONDITIONS
PREVAIL WITH BROAD HIGH PRESSURE SLOWLY BUILDING ACROSS THE
WATERS.
HIGH PRESSURE CONTINUES TO RESIDE OVERHEAD THROUGH TUESDAY
MORNING. A WEAK WARM FRONT MAY DRAPE OVER THE WATERS THROUGH
MIDWEEK WITH STRONG HIGH PRESSURE REMAINING OVER THE DEEP SOUTH.
GYX WATCHES/WARNINGS/ADVISORIES
ME...NONE.
NH...NONE.
MARINE...NONE.
DISCUSSION...SCHROETER/TUBBS
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