325  
FXUS61 KGYX 192352  
AFDGYX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAY ME  
752 PM EDT WED SEP 19 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL BUILD IN FROM THE NORTHEAST TONIGHT AND WILL  
HOLD OVER THE REGION ON THURSDAY. A WARM FRONT WILL LIFT NORTH  
TO THE WEST OF THE FORECAST AREA THURSDAY NIGHT AND FRIDAY. A  
COLD FRONT WILL CROSS THE REGION FRIDAY NIGHT FOLLOWED BY HIGH  
PRESSURE ON SATURDAY. A SECONDARY COLD FRONT WILL PUSH SOUTH  
THROUGH THE REGION SUNDAY. HIGH PRESSURE WILL BUILD OVER THE  
REGION SUNDAY NIGHT AND MONDAY.  
 

 
   
NEAR TERM /UNTIL 6 AM THURSDAY MORNING/
 
 
745 PM...NE FLOW BELOW INVERSION IS ALLOWING NOT ONLY FOR CLOUDS  
BUT A FEW LIGHT SHRA AND SPRINKLES IN THE UPSLOPE AREAS OF THE  
MTNS AND FOOTHILLS /WHICH WERE SHOWING UP ON RADAR BEFORE THE  
BIOLOGICAL ECHOES APPEARED/. THE PRECIP SHOULD WANE AS THE  
EVENING PROGRESSES AND FLOW BEGINS TO SUBSIDE. OTHERWISE IT'LL  
STAY MAINLY CLOUDY OVERNIGHT, WITH LOWS IN THE MID TO UPPER 40S  
IN THE MTNS TO LOW TO MID 50S IN SRN NH AND ALONG THE COAST.  
SOME VALLEY FOG COULD FORM IN THE SRN HALF OF THE CT VLY IN OUR  
CWA, GIVEN THE CLEARER SKIES.  
 
PREVIOUSLY...MOIST FLOW OFF THE MARITIMES WILL CONTINUE  
OVERNIGHT AS HIGH PRESSURE BUILDS IN FROM THE NORTHEAST. SHARP  
TEMP INVERSION AROUND 2500 FT WILL KEEP LOW CLOUDS ACROSS MUCH  
OF THE REGION INTO THURSDAY MORNING. ANY AREAS IN THE  
CONNECTICUT VALLEY WHICH SCATTER OUT WILL LIKELY SEE FOG  
DEVELOPING AFTER MIDNIGHT. LOWS OVERNIGHT WILL RANGE FROM THE  
MID 40S NORTH TO THE MID 50S SOUTH.  
 

 
   
SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/
 
 
LOW LEVEL MOISTURE WILL LINGER OVER THE REGION ON THURSDAY BUT  
EXPECT SUNNY BREAKS TO DEVELOP DURING THE MORNING AND EARLY  
AFTERNOON THROUGHOUT THE FORECAST AREA. HIGH TEMPS WILL AVERAGE  
OUT BELOW NORMAL WITH HIGHS IN THE LOWER TO MID 60S.  
 
A WARM FRONT LIFTING BY TO THE NORTHWEST OF THE REGION THURSDAY  
NIGHT WILL BRING INCREASING HIGH AND MID LEVEL CLOUDS INTO THE  
REGION AND MAY SCRAPE NORTHERN ZONES WITH A FEW SHOWERS AFTER  
MIDNIGHT. LOWS WILL RANGE FROM THE MID 40S NORTH TO THE MID 50S  
SOUTH.  
 

 
   
LONG TERM /FRIDAY THROUGH WEDNESDAY/
 
 
GLOBAL MODELS ARE IN REASONABLY GOOD AGREEMENT THROUGH THE  
PERIOD. A WARM FRONT WILL LIFT NORTH EARLY ON FRIDAY. LOOKS  
LIKE BEST MOISTURE AND LIFT WILL BE FROM CENTRAL NH OVER TO  
THE MAINE FOOT HILLS AND MOUNTAINS. THEREFORE THE BEST CHANCE  
OF MORNING SHOWERS WILL BE OVER THESE AREAS. FRIDAY AFTERNOON A  
TIGHTENING SW GRADIENT SHOULD RESULT IN BREEZY AND MILD  
CONDITIONS.  
 
FRIDAY NIGHT A SHARP COLD FRONT WILL SWEEP THROUGH THE REGION.  
EXPECT FRONTAL PASSAGE AROUND 4 UTC OVER THE MOUNTAINS AND  
AROUND 9 UTC ALONG THE COASTLINE. STRONG WIND DYNAMICS ARE  
ASSOCIATED WITH THIS FRONT BUT AS PREVIOUSLY DISCUSSED THE  
TIMING OF THE THE EVENT MEANS THAT MUCH OF THE DAYTIME HEATING  
AND INSTABILITY WILL NOT BE PRESENT. STILL CAN'T RULE OUT SOME  
STRONGER WIND GUSTS WITH THE FROPA (FRONTAL PASSAGE) AND ANY  
ASSOCIATED CONVECTION. HAVE USED THE GYX PEAK WIND GUST TOOL  
FROM 21 UTC FRIDAY THROUGH 15 UTC SATURDAY. THIS YIELDS WIND  
GUSTS IN THE 40 TO 50 MPH RANGE OVER HIGH TERRAIN WITH GUSTS  
OVER 90 MPH OVER THE HIGHER PEAKS OF THE WHITE MOUNTAINS. OVER  
THE LOWER TERRAIN THE GUSTS LOWER SIGNIFICANTLY PEAKING IN THE  
20 TO 30 MPH RANGE. IF SUBSEQUENT GUIDANCE INCREASES WINDS  
SPEEDS WE MAY NEED TO CONSIDER WIND HEADLINES...SINCE IT IS IN  
THE 48 TO 60 HOUR RANGE THERE IS TIME TO EVALUATE THIS.  
 
POST FRONTAL, A LARGE COOL CANADIAN HIGH PRESSURE SYSTEM WILL  
START TO BUILD SOUTH. INITIALLY WE WILL BE IN A COOL NW FLOW OF  
AIR AHEAD OF THE HIGH. THERE WILL BE A TROUGH/SECONDARY SHOT OF  
COOL AIR CROSSING AHEAD OF THE HIGH SATURDAY NIGHT. THE HIGH  
WILL BUILD OVER THE AREA LATE SUNDAY AND MONDAY. THE HIGH WILL  
PUSH EAST OF THE REGION TUESDAY ALLOWING FOR MODERATING  
TEMPERATURES AS A SW FLOW DEVELOPS. ANOTHER WARM FRONT-COLD  
FRONT COUPLET WILL RETURN THE THREAT OF SHOWERS LATE TUESDAY AND  
WEDNESDAY.  
 

 
   
AVIATION /00Z THURSDAY THROUGH MONDAY/
 
 
SHORT TERM...WIDESPREAD MVFR/IFR CEILINGS TONIGHT WITH AREAS OF  
LIFR IN PATCHY FOG AFTER MIDNIGHT. BECOMING VFR ON THURSDAY AND  
THURSDAY NIGHT.  
 
LONG TERM...VFR TO MVFR SOUTH OF THE MOUNTAINS FRIDAY...AREAS OF  
IFR IN SHOWERS FRIDAY MORNING OVER THE MOUNTAINS. A COLD FRONT  
WILL CROSS THE REGION FRIDAY NIGHT WITH SHOWERS AND  
THUNDERSTORMS RESULTING IN AREAS OF IFR TO LIFR IN ANY  
THUNDERSTORMS. HIGH PRESSURE WILL RETURN VFR TO MVFR CONDITIONS  
SATURDAY THROUGH MONDAY. THE ONLY EXCEPTION WOULD BE OVER THE  
MOUNTAINS WHERE MVFR TO IFR CONDITIONS ARE POSSIBLE SATURDAY  
MORNING.  
 

 
   
MARINE
 
 
SHORT TERM...NORTHEASTERLY FLOW WILL CONTINUE TONIGHT INTO  
THURSDAY BUT WINDS WILL REMAIN BELOW SCA LEVELS.  
 
LONG TERM...WINDS AND WAVES HEIGHTS WILL LIKELY REACH SCA LEVELS  
FRIDAY AFTERNOON THROUGH FRIDAY NIGHT AND INTO EARLY SATURDAY AS  
A STRONG COLD FRONT APPROACHES AND CROSSES THE WATERS. ANOTHER  
ROUND OF SCA WINDS AND WAVES ARE POSSIBLE TUESDAY INTO  
WEDNESDAY.  
 

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

 
 

 
SYNOPSIS...  
NEAR TERM...CEMPA/SINSABAUGH  
SHORT TERM...SINSABAUGH  
LONG TERM...LULOFS  
AVIATION...  
MARINE...  
 
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