051  
FXUS61 KGYX 252048  
AFDGYX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAY ME  
348 PM EST SAT JAN 25 2020  
   
SYNOPSIS
 
 
LOW PRESSURE WILL CROSS THE REGION THIS EVENING BRINGING A MIX  
OF SNOW NORTH AND RAIN IN THE SOUTH. NORTHWESTERLY FLOW WILL SET  
UP WITH CLOUDS AND SNOW SHOWERS LINGERING IN THE MOUNTAINS  
THROUGH TUESDAY. A FEW FLURRIES REMAIN POSSIBLE THROUGH  
WEDNESDAY, BUT THEN A STRONG HIGH WILL BUILD IN FOR THE SECOND  
HALF OF THE WEEK WITH CLEAR SKIES AND COLD OVERNIGHT  
TEMPERATURES.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
***SHORT DURATION HEAVY RAINFALL EXPECTED TONIGHT***  
 
A WEAKER ATMOSPHERIC RIVER OF MOISTURE AHEAD OF AN OCCLUDED  
FRONT WILL CROSS THE REGION LATE THIS AFTERNOON THROUGH LATE  
THIS EVENING. 25.12Z HREF IS FORECASTING 1 TO 2 INCHES OF  
RAIN...WITH THE MAJORITY OF THAT FALLING IN A 3 HOUR WINDOW.  
THIS IS SUPPORTED BY UPSTREAM OBSERVATIONS OF 1 INCH PER HOUR IN  
PARTS OF NY...PA...AND NJ. GIVEN THE FRESH SNOWPACK I EXPECT  
THAT IT WILL ABSORB MUCH OF THAT RAINFALL DESPITE THE HEAVY  
RATES. THE BIGGER CONCERN IS THAT SNOWBANKS ARE COVERING STORM  
DRAINS IN MANY AREAS AND THE FASTER RUNOFF ON STREETS IN THE  
URBAN AREAS MAY LEAD TO EXCESSIVE PONDING AND MINOR FLOODING.  
FLOOD WATCH REMAINS IN EFFECT FOR THIS REASON...MORE DETAILS IN  
HYDROLOGY SECTION BELOW.  
 
STILL SEEING POCKETS OF SUB-FREEZING AIR ACROSS NRN ZONES AND  
INTO THE FOOTHILLS. INCREASING ONSHORE FLOW AND INCREASING WINDS  
ON TOP OF THAT LAYER ARE LEADING TO MORE WIDESPREAD DRIZZLE AND  
FREEZING DRIZZLE. IT LOOKS LIKE THE WINTER WX ADVISORY COVERS  
THE FREEZING DRIZZLE AREAS WELL AND NO CHANGES WERE MADE TO  
HEADLINES. THE SRN ADVISORY AREAS WILL EVENTUALLY CHANGE TO  
RAIN. THE NRN ADVISORY AREAS WILL SEE SOME AREAS REMAIN BELOW  
FREEZING AND A SLIGHT LONGER PERIOD OF SLEET OR FREEZING RAIN  
AFTER INITIAL SNOW. OVERALL WARMING ALOFT AND SHORT DURATION ARE  
EXPECTED TO KEEP AMOUNTS ON THE LIGHT SIDE. WILL HAVE TO KEEP AN  
EYE ON FREEZING LEVELS...AS FORECAST SOUNDINGS INDICATE THE  
HIGHEST SUMMITS MAY HANG ON TO ALL SNOW. IF THAT LOWERS A BIT  
THAT COULD BRING THE WRN ME SUMMITS LIKE SUGARLOAF INTO PLAY FOR  
HIGHER SNOW TOTALS.  
 
FINALLY SE LLJ WILL INCREASE OVERNIGHT AND PEAK AROUND MIDNIGHT  
GIVE OR TAKE AN HOUR BASED ON LOCATION. NAM IS PROBABLY THE MOST  
AGGRESSIVE OF ANY MODEL...WITH 60 KNOTS BELOW 900 MB. EVEN IN  
THAT SCENARIO THE EXPECTATION WOULD BE FOR GUSTS IN THE 35 TO 40  
MPH RANGE. SO I HAVE KEPT WIND GUSTS OVERNIGHT GENERALLY BELOW  
30 KT OUTSIDE THE MIDCOAST.  
 

 
   
SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/
 
 
FORECAST AREA REMAIN IN CYCLONIC FLOW AND TRAPPED LOW LEVEL  
MOISTURE SHOULD KEEP PLENTY OF CLOUD COVER IN WLY UPSLOPE ZONES  
INTO MON MORNING. I EXPECT SNOW SHOWERS AS WELL...WITH AT LEAST  
LIGHT ACCUMULATIONS IN THE HIGHER TERRAIN.  
 
TEMPS WILL BE MILD SUN AS COLDER AIR DELAYS UNTIL UPPER TROF  
AXIS PASSES. GIVEN THAT OCCURS OVERNIGHT AND CAA SHOULD KEEP  
BOUNDARY LAYER SOMEWHAT MIXED I BLENDED IN RAW 2 M TEMPS TO  
TREND DOWN TO LOWS MON MORNING.  
 

 
   
LONG TERM /MONDAY THROUGH SATURDAY/
 
 
UPSLOPE FLOW CONTINUES THROUGH THE FIRST PART OF THE WEEK AS AN  
UPPER LEVEL LOW SLOWLY PULLS NORTHEASTWARDS INTO THE MARITIMES.  
NORTHWESTERLY FLOW WILL RESULT IN DOWNSLOPING INTO THE COASTAL  
PLAIN WITH CLEAR SKIES ACROSS THE SOUTH AND MOSTLY OVERCAST WITH  
SNOW FLURRIES IN THE NORTH.  
 
THROUGH THE MIDDLE PART OF THE WEEK SPLIT FLOW DEVELOPS OVER THE  
CENTRAL PART OF NORTH AMERICA. WHILE SOME WEAK WAVES PASS BOTH  
NORTH AND SOUTH OF US WE REMAIN LARGELY AVERAGE WITH JUST A  
CHANCE FOR PRECIP ON WEDNESDAY WHEN THE NORTHERN STREAM WAVE  
APPROACHES. HAVE INCREASED POP FOR THE MOUNTAINS ON WEDNESDAY AS  
SOUNDINGS SHOW ENOUGH LIFT TO EEK OUT SOME FLURRIES DESPITE THE  
DRY AIR MASS.  
 
STRONG HIGH PRESSURE WILL BUILD INTO THE REGION FOR THE END OF THE  
WEEK. WITH CLEAR, DRY, AND CALM CONDITIONS EXPECT OVERNIGHT  
LOWS TO DROP QUITE WELL IN THE MOUTNAINS AND HAVE LEANED TOWARDS  
THE COLDER STATISTICAL GUIDANCE FOR THIS.  
 
GLOBAL ENSEMBLES WOULD POINT TOWARDS A BREAKDOWN OF THIS PATTERN FOR  
THE END OF THE WEEK AS THE BLOCK IN THE PACIFIC BREAKS DOWN AND  
WE SEE A WAVE TRAIN PROPAGATE ALL THE WAY TO THE EAST COAST BY  
SATURDAY. WITH THIS TYPE OF SCENARIO THE MOST SUSPECT PART IS  
THE TIMING. THE SPLIT FLOW AND BLOCKS CAN'T LAST FOREVER, AND  
IT'S LIKELY A TROUGH WILL DEVELOP OVER THE EASTERN CONUS  
RETURNING US TO THE STORM TRACK, BUT THE TIME OF RETURN COULD BE  
AS LATE AS THE END OF THE WEEKEND OR EARLY NEXT WEEK. WITH LOW  
CONFIDENCE HAVE KEPT POPS TO UNDER 30 THROUGH THE WEEKEND TIME  
FRAME.  
 

 
   
AVIATION /20Z SATURDAY THROUGH THURSDAY/
 
 
SHORT TERM...WIDESPREAD MVFR CIGS CONTINUE TO GRADUALLY LOWER  
WITH SOME AREAS OF IFR NOW FILLING IN. THAT TREND WILL CONTINUE  
INTO THE EARLY EVENING WHERE WIDESPREAD IFR OR LOWER CIGS ARE  
EXPECTED S OF THE MTNS. ADDITIONALLY VIS WILL LOWER IN POCKETS  
OF DZ...ESPECIALLY WHERE SLIGHTLY UPSLOPING SE FLOW OCCURS.  
RA/+RA MOVES IN FROM W TO E TONIGHT GENERALLY BETWEEN 00Z AND  
06Z. LLWS IS ALSO EXPECTED BEGINNING LATE THIS AFTERNOON THRU  
LATE TONIGHT. LLWS AND +RA COME TO A QUICK END BEHIND THE  
OCCLUSION BETWEEN 06Z TO 09Z. VFR CONDITIONS EXPECTED S OF THE  
MTNS THRU SUN NIGHT...UPSLOPE SHSN AND MVFR CIGS EXPECTED N. HIE  
MAY SEE LOCAL IFR IN ANY SHSN.  
 
LONG TERM... MVFR CLOUDS AND SNOW SHOWERS WILL LINGER IN THE  
MOUNTAINS THROUGH THE FIRST PART OF THE WEEK. ELSEWHERE VFR WILL  
PREVAIL IN DOWNSLOPE NORTHWESTERLY FLOW. BY MIDWEEK A STRONG  
HIGH WILL BEING TO BUILD INTO THE REGION AND HOLD THROUGH THE  
END OF THE WEEK KEEPING CONDITIONS VFR.  
 

 
   
MARINE
 
 
SHORT TERM...GALES WARNINGS REMAIN IN EFFECT FOR ALL WATERS WITH  
STRONG SELY LLJ EXPECTED TONIGHT. GALES SHOULD BE RELATIVELY  
SHORT DURATION...WITH A ROUGHLY 6 HOUR WINDOW OF STRONGEST WIND  
GUSTS. WINDS AND SEAS GRADUALLY DIMINISH AS OFFSHORE SCA GUSTS  
SUN KEEP SEAS CONFUSED.  
 
LONG TERM... NORTHWESTERLY FLOW WILL DEVELOP IN THE WAKE OF THE  
DEPARTING LOW FOR THE START OF THE WEEK, WITH A FEW GUSTS TO SCA  
ON THE OUTER WATERS POSSIBLE. HIGH PRESSURE WILL BUILD IN FOR  
THE END OF THE WEEK WITH CALM SEAS AND WINDS.  
 

 
   
HYDROLOGY
 
 
QUICK HITTING HEAVY RAINFALL WILL MOVE THROUGH THE SOUTHERN  
PORTION OF THE REGION TONIGHT WITH WIDESPREAD 1-2 INCHES  
EXPECTED IN JUST OVER 6 HOURS. WATER VAPOR IMAGERY SHOWS A DEEP  
MOISTURE PLUME EXTENDING WELL SOUTH INTO THE CAPE HATTERAS  
REGION AHEAD OF A COLD FRONT. THIS MOISTURE PLUME WILL MEET BOTH  
THE TOPOGRAPHY OF THE MOUNTAINS, AS WELL AS THE CONVERGENCE  
ALREADY SEEN IN THE SURFACE OBSERVATIONS ALONG THE COASTAL FRONT  
AND THE COMBINATION WILL FOCUS PRECIPITATION JUST INLAND OF THE  
COAST. WITH FROZEN GROUND AND DRAINS BLOCKED BY SNOW THE IMPACT  
WILL BE MORE THAN NORMAL FOR THIS RAINFALL AMOUNT AND A FLOOD  
WATCH HAS BEEN ISSUED FOR THE COASTAL AREAS.  
 
FOR THE RIVERS EXPECT MOST POINTS TO STAY BELOW ACTION AS THE  
SNOWPACK ACROSS THE REGION REMAINS AT AROUND 20-25% DENSITY AND  
WILL BE ABLE TO ABSORB QUITE A BIT OF THE RAIN. POINTS TO WATCH  
IN SOUTHERN NH INCLUDE THE LAMPREY WHICH MAY REACH ACTION AND  
SUNCOOK AT NORTH CHICHESTER WHERE BOTH THE HEAVY RAIN AND ICE  
AFFECTS MAY COMBINE TO REACH ACTION. ACROSS SOUTHERN MAINE, THE  
PRESUMPSCOT AT WESTBROOK IS EXPECTED TO PEAK AROUND 10FT, BUT  
WITH THE FOCUS OF THE MESOSCALE RAINFALL WITHIN THE BASIN IT HAS  
THE POTENTIAL TO REACH ACTION AS WELL. A FINAL NOTE IS THAT THE  
ICE JAM REMAINS IN PLACE ON THE KENNEBEC AT AUGUSTA. ALTHOUGH  
WATER LEVELS HAVE CONTINUED TO DROP AND NOT A LOT OF RUNOFF IS  
EXPECTED TO REACH THE MAINSTEM KENNEBEC THE ICE JAMS COULD MOVE  
AT ANY TIME.  
 

 
   
TIDES/COASTAL FLOODING
 
 
EAST FLOW INCREASING TODAY BROUGHT STORM SURGE ABOVE A HALF FOOT  
THIS MORNING. WITH INCREASING WINDS EXPECTED TONIGHT I EXPECTED  
AT LEAST A FOOT OF SURGE ON TOP OF THE TIDE. GIVEN THIS IS THE  
LOWER OF THE DAILY TIDES I DO NOT ANTICIPATE ANY FLOODING...BUT  
SPLASHOVER IS LIKELY WITH BUILDING NEARSHORE WAVES. THE 10.0 FT  
NOON TIDE SUNDAY MAY ALSO SEE ADDITIONAL SPLASHOVER...BUT  
OFFSHORE WINDS SHOULD AGAIN MITIGATE THE FLOODING THREAT.  
 

 
   
GYX WATCHES/WARNINGS/ADVISORIES
 
 
ME...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR MEZ012>014.  
FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH LATE TONIGHT  
FOR MEZ018-019-023>026.  
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST  
SUNDAY FOR MEZ007>009.  
NH...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR NHZ001>005.  
FLOOD WATCH FROM 7 PM EST THIS EVENING THROUGH LATE TONIGHT  
FOR NHZ010-012>014.  
MARINE...GALE WARNING FROM 7 PM THIS EVENING TO 7 AM EST SUNDAY FOR  
ANZ150>154.  
 

 
 

 
 
SYNOPSIS...CURTIS  
NEAR TERM...LEGRO  
SHORT TERM...LEGRO  
LONG TERM...CURTIS  
 
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