332  
FXUS61 KGYX 091416  
AFDGYX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAY ME  
1016 AM EDT FRI MAY 9 2025  
   
SYNOPSIS
 
 
A SLOW MOVING LOW PRESSURE BRINGS WIDESPREAD RAINFALL  
TODAY THROUGH SATURDAY. RAINFALL COULD BE HEAVY AT TIMES AND  
WITH ALREADY SATURATED CONDITIONS IN PARTS OF THE AREA, A MINOR  
FLOODING THREAT COULD DEVELOP. THIS RAINFALL WILL PUSH AREA  
RIVERS AND STREAMS TO NEAR BANKFULL AND IN SOME CASES INTO MINOR  
FLOOD STAGE. THIS COULD RESULT IN A MINOR FLOOD THREAT THROUGH  
THE WEEKEND AS RIVERS REMAIN HIGH. WARMER AND DRIER CONDITIONS  
RETURN WITH HIGH PRESSURE FOR SUNDAY AND EARLY NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
1000 AM UPDATE...CURRENT RADAR IMAGERY SHOWS SOME SCATTERED  
SHOWERS MOVING NORTHWARD ACROSS NORTHERN NH AND WESTERN ME, WITH  
THE BULK OF THE PRECIPITATION STILL TO OUR WEST IN VERMONT. THIS  
AXIS OF RAIN POSITIONED OVER THE GREEN MOUNTAINS IS MOVING  
EASTWARD SLOWER THAN PREVIOUSLY EXPECTED, LOWERED QPF AMOUNTS A  
LITTLE AND TRIMMED BACK POPS TO MATCH MOST RECENT GUIDANCE AND  
THE LATER ONSET OF THIS BATCH OF RAIN. IN ADDITION, ADDED PATCHY  
FOG TO THE FORECAST AND DAMPENED DOWN HIGH TEMPERATURES A  
BIT. THESE CHANGES WERE MADE MAINLY TO ACCOUNT FOR DENSE AND  
LOW CLOUDS OVER THE AREA, WITH FOG ALREADY BEING OBSERVED ACROSS  
MUCH OF SOUTHERN NH.  
 
625 AM UPDATE...MAINLY JUST REFINED POPS AS SHOWERS CONTINUE TO  
PUSH THROUGH THE AREA AHEAD OF THE MORE ORGANIZED AREA OF RAIN  
JUST TO OUR SOUTHWEST. OTHERWISE, JUST MINOR UPDATES TO REFLECT  
LATEST OBSERVATIONS.  
 
PREVIOUS DISCUSSION...  
IMPACTS AND KEY MESSAGES:  
* WIDESPREAD SHOWER ACTIVITY TODAY WILL CONTINUE TO PRIME CONDITIONS  
FOR A MINOR FLOOD THREAT HEADING INTO THE EVENING.  
 
A WEAKENING AREA OF SHOWERS CONTINUES TO MOVE NORTHWARD ALONG THE  
MAINE AND NEW HAMPSHIRE BORDER. RAIN RATES WERE MODERATE OVERNIGHT  
AT TIMES WITH A GOOD NUMBER OF GAUGES PICKING UP AROUND A HALF INCH  
OVER THE LAST 6 HOURS IN SOUTHERN AND CENTRAL NEW HAMPSHIRE. A FEW  
SHOWERS ARE PUSHING INTO SOUTHWESTERN NEW HAMPSHIRE, RATES AT THIS  
HOUR ARE LIGHT. MUCH OF THE AREA WILL ACTUALLY BE MOSTLY DRY THIS  
MORNING AS AN UPPER LOW CONTINUES IT'S APPROACH. CURRENT RAP13  
ANALYSIS PUTS IT OVER THE GREAT LAKES REGION, WITH THE SURFACE LOW  
JUST EMERGING OFF THE DELMARVA COAST. THE SHOWERS ASSOCIATED WITH  
THIS LOW ARE CURRENTLY IN EASTERN PENNSYLVANIA AND WILL BEGIN TO  
ENTER OUR AREA EARLY THIS AFTERNOON, OVERSPREADING THE AREA FROM  
WEST TO EAST. PWATS WON'T BE AS HIGH AS LATER IN THE EVENING AT THIS  
POINT, BUT MODERATE RAIN RATES ARE STILL LIKELY. WHILE FLOODING  
ISSUES AREN'T EXPECTED AT THE INITIAL ONSET OF THESE SHOWERS, THIS  
WILL BE A GOOD PRIMER AHEAD OF EXPECTED INCREASED RATES LATER.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/
 
 
IMPACTS AND KEY MESSAGES:  
* THE HEAVIEST RAINFALL RATES ARE EXPECTED TO OCCUR FRIDAY NIGHT.  
WITH VERY WET ANTECEDENT CONDITIONS MINOR FLOODING OF POOR  
DRAINAGE AREAS.  
* AREA RIVERS AND STREAMS ARE EXPECTED TO SEE RISES THROUGH SATURDAY  
WITH A COUPLE OF THEM REACHING MINOR FLOOD STAGE.  
 
TONIGHT: THE UPPER LEVEL LOW BEGINS TO PHASE WITH SURFACE LOW  
PRESSURE JUST TO OUR SOUTH. THIS WILL HELP TO AMPLIFY THE SURFACE  
LOW INCREASING COVERAGE AND INTENSITY OF SHOWERS. A 35KT LOW LEVEL  
WILL ALSO HELP TO INCREASE RATES BY STARTING THE MOISTURE SURGE  
DURING THIS PERIOD. LATEST HI-RES GUIDANCE SUGGESTS WIDESPREAD PWATS  
AROUND AN INCH OVER THE SOUTHERN HALF OF NEW HAMPSHIRE AND THE  
COASTAL PLAIN. THE OVERNIGHT PERIOD IS LIKELY TO BE WHERE WE WOULD  
SEE THOSE MINOR FLOODING ISSUES BEGIN IN URBAN AND POOR DRAINAGE  
AREAS AS AN UPPER LEVEL LOW MOVING OVERHEAD LEADS TO SHOWERS  
ORIENTING THEMSELVES IN A SOUTH TO NORTH FASHION. WITH ALREADY VERY  
WET CONDITIONS ACROSS SOUTHERN NEW HAMPSHIRE, TRAINING OR JUST  
REPEATED ROUNDS OF HEAVY SHOWERS COULD BEGIN TO CAUSE SOME AREAL  
FLOOD ISSUES. FOR FURTHER DETAILS ON THE GENERAL FLOOD THREAT SEE  
THE HYDROLOGY SECTION BELOW.  
 
SATURDAY: WIDESPREAD RAIN SHOWERS WILL BE ONGOING SATURDAY MORNING  
AS LOW PRESSURE BECOMES VERTICALLY STACKED OVER THE AREA. THE  
MOISTURE AXIS CONTINUES MOVING NORTH AND EAST AS WELL SO HEAVY  
RAINFALL RATES WILL REMAIN PRESENT WITH SOUTHEASTERLY FLOW DIRECTLY  
OFF THE ATLANTIC PUSHING PWATS UP TOWARD 1.25" ON THE COASTAL PLANE.  
HEADING TOWARD THE AFTERNOON WE WILL BEGIN TO SEE RAINFALL RATES  
DECREASE AND SHOWERS CLEAR FROM SOUTHWEST TO NORTHEAST AS LOW  
PRESSURE MAKES A SWIFT EXIT AND FLOW TURNS NORTHWESTERLY. WHEN ALL  
IS SAID AND DONE QPF AMOUNTS LOOK TO BE A WIDESPREAD 1.5-2 INCHES  
WITH LOCALLY HIGHER AMOUNTS NEARING 3 INCHES POSSIBLE. THE EXCEPTION  
WILL BE NORTH OF THE MOUNTAINS WHERE SOME SHADOWING MAY KEEP AMOUNTS  
MORE IN THE 1-1.5 INCH RANGE. PLENTY OF CLOUDS AND RAIN WILL LIMIT  
HIGH TEMPERATURES TO THE UPPER 40S AND LOW 50S. BY SATURDAY EVENING  
THE AREA LOOKS PRETTY MUCH PRECIPITATION FREE, BUT RUNOFF FROM THE  
RECENT RAINS WILL CONTINUE TO DUMP INTO AREA RIVERS PUSHING THEM TO  
BANKFULL OR EVEN INTO MINOR FLOOD STAGE IN A COUPLE CASES. BREEZY  
NORTHWESTERLY WINDS FOLLOW IN THE WAKE OF THE DEPARTING LOW ALONG  
WITH CLEARING SKIES.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/
 
 
LONG TERM UPDATE...VERY LITTLE CHANGE TO THE LONG TERM FORECAST  
AT THIS TIME. 01Z NBM IS IN LINE WITH PREVIOUS FORECASTS AND  
OTHER ENSEMBLE DATASETS AS WE CAN EXPECT DRYING AND WARMING FOR  
SUNDAY INTO EARLY NEXT WEEK.  
 
PREVIOUSLY...  
 
OTHER THAN A FEW SHOWERS ACROSS NORTHERN AREAS LATE MONDAY INTO  
MONDAY NIGHT, A RIDGE OF HIGH PRESSURE BUILDS TOWARD THE  
NORTHEASTERN US SUNDAY INTO EARLY NEXT WEEK, OFFERING A STRETCH  
OF DRY AND WARMER WEATHER. SUNDAY'S TEMPS EXPECTED TO BE THE MID  
60S TO LOW 70S, BUT THEN THE LOW-LEVEL HIGH SHIFTS TO THE SOUTH  
AND EAST EARLY NEXT WEEK, BRINGING A RETURN TO MORE SOUTH TO  
SOUTHWEST FLOW THAT WILL USHER IN EVEN WARMER TEMPERATURES THAT  
MAY STICK AROUND THROUGH MIDWEEK. FOR MONDAY, EXPECTING  
GENERALLY 70S OVER MUCH OF THE AREA, EXCEPT THE ONSHORE  
COMPONENT WILL PROBABLY KEEP THE COAST AND EASTERN AREAS IN THE  
60S. GUIDANCE HAS THEN TRENDED WARMER FOR TUES-WEDS WITH 70S  
LOOKING MORE LIKELY ACROSS THE INTERIOR WITH LOW 80S EVEN  
POSSIBLE AS HEIGHTS CONTINUE TO RISE, BUT THE COAST WILL  
PROBABLY STAY A BIT COOLER WITH THE SEA BREEZE.  
 
FOR WEDNESDAY AND THURSDAY, THERE'S GOOD AGREEMENT IN BRINGING  
AN UPPER TROUGH TOWARD THE EAST COAST, BUT THE DIFFERENCES ARE  
WHERE. THERE'S SUPPORT FOR THE RIDGE HOLDING STRONG OVER NEW  
ENGLAND TO KEEP THE TROUGH SOUTH, WHICH WOULD PROLONG THE DRY  
AND WARM STRETCH. ON THE OTHER HAND, THERE'S ALSO SOME SUPPORT  
WITHIN THE ENSEMBLES TO WEAKEN THE RIDGE AND SHIFT IT TO THE  
EAST, WHICH BRING THE NEXT CHANCE OF SHOWERS. THE NBM 20% POPS  
WEDNESDAY AND THEN 30% FOR NEXT THURSDAY ARE GOOD FOR NOW GIVEN  
THE UNCERTAINTY.  
 

 
   
AVIATION /14Z FRIDAY THROUGH TUESDAY/
 
 
SHORT TERM...NOT MUCH IN THE WAY OF IMPROVEMENT IS EXPECTED  
TODAY AS CEILINGS REMAIN LOW BETWEEN ROUNDS OF RAIN. THE NEXT  
ROUND OF RAIN ARRIVES LATE/MORNING EARLY AFTERNOON AND WILL  
BRING ABOUT VISIBILITY RESTRICTIONS AS IT WILL BE HEAVY AT TIMES  
THROUGH TOMORROW. SATURDAY EVENING IS WHEN RAIN WILL TAPER OFF  
AND CEILINGS WILL TREND TOWARD VFR.  
 
LONG TERM...LINGERING SHOWERS AND RESTRICTIONS ARE POSSIBLE  
INTO SATURDAY EVENING TOWARD RKD/AUG AND THEN HIE THROUGH  
SATURDAY NIGHT, BUT IN GENERAL CONDITIONS CONTINUE TO IMPROVE AS  
LOW PRESSURE DEPARTS THE REGION. THAT SAID, WILL HAVE TO WATCH  
FOR FOG DEVELOPMENT SATURDAY NIGHT GIVEN THE WIDESPREAD RAIN  
FRIDAY INTO SATURDAY. VFR EXPECTED SUN-TUES.  
 

 
   
MARINE
 
 
SHORT TERM...LOW VISIBILITIES IN HEAVY RAIN AND FOG WILL  
PERSIST THROUGH SATURDAY AS LOW PRESSURE MOVES THROUGH THE  
REGION. THIS WILL ALSO BRING ABOUT SEAS BUILDING TO AROUND 6FT.  
NORTHEASTERLY WIND GUSTS WILL NEAR 25KTS TODAY AND SATURDAY  
BEFORE SHIFTING TO WESTERLY BY THE END OF THE DAY SATURDAY AS  
LOW PRESSURE MAKES ITS JOURNEY UP THE COAST.  
 
LONG TERM...LOW PRESSURE DEPARTS INTO THE CANADIAN MARITIMES  
SATURDAY NIGHT, AND NORTHWEST WINDS ON THE BACKSIDE OF THE LOW  
COULD EXCEED SCA LEVELS DURING THIS PERIOD. CONDITIONS REMAIN  
BELOW SCA LEVELS SUNDAY AND SUNDAY NIGHT AS HIGH PRESSURE BUILDS  
IN. IN GENERAL, FLOW LOOKS TO REMAIN SOUTH OR SOUTHWESTERLY FOR  
THE EARLY TO MIDDLE PART OF NEXT WEEKEND AS THE HIGH BECOMES  
CENTERED SOUTHEAST OF THE WATERS. THERE MAY BE ANOTHER PERIOD OF  
SCA CONDITIONS MONDAY INTO MONDAY NIGHT AS THE GRADIENT  
TIGHTENS BETWEEN THE HIGH AND A WEAK DISTURBANCE PASSING TO THE  
NORTH.  
 

 
   
HYDROLOGY
 
 
1000 AM UPDATE...ADDED ROCKINGHAM AND STRAFFORD COUNTIES TO THE  
FLOOD WATCH, MAINLY TO DUE TO THE MEASURABLE RAINFALL SEEN THERE LAST  
NIGHT. THE ADDITIONAL RAIN COULD INCREASE CHANCES FOR SMALL  
STREAM FLOODING AND LOCALIZED MINOR MAINSTEM RIVER FLOODING AS  
MORE SOAKING RAIN ARRIVES THIS EVENING.  
 
PREVIOUSLY...RECENT SHOWERS HAVE BROUGHT AN AVERAGE OF 1 TO 2  
INCHES OF RAINFALL FROM THE MOUNTAINS NORTHWARD, AND 2 TO 4+  
INCHES SOUTHWARD OVER THE LAST 7 DAYS. AS A RESULT, STREAMFLOWS  
ARE RUNNING ABOVE NORMAL, PARTICULARLY IN THE CONNECTICUT AND  
MERRIMACK WATERSHEDS. SOIL MOISTURE LEVELS ARE NEAR 75-95%, AND  
DESPITE GREEN-UP THERE REMAINS A LIMITED CAPACITY OF ABSORPTION.  
RAINFALL OVERNIGHT THURSDAY WAS GENERALLY 0.25-0.50" WITH SOME  
LOCALLY HIGHER AMOUNTS AND WAS HEAVIEST NEAR THE CONNECTICUT  
RIVER AND PARTS OF SOUTHERN NEW HAMPSHIRE. CONFIDENCE IS  
INCREASING THAT THE TODAY-SAT SYSTEM WILL PRODUCE A WIDESPREAD 1  
TO 3 INCHES WITH LOCALLY HIGHER AMOUNTS. REFINEMENT IS NEEDED  
ON THE SYSTEM TIMING AND POTENTIAL FOR A DRY SLOT SAT MORNING.  
DESPITE THESE DETAILS, THE OVERALL EFFECT WILL BE ADDITIONAL  
STREAM RISES WHICH IS LIKELY TO CAUSE SMALL STREAM FLOODING AND  
LOCALIZED MINOR MAINSTEM RIVER FLOODING. CONFIDENCE IS HIGH THAT  
THE RAINFALL WILL BE INSUFFICIENT TO CAUSE ANY SIGNIFICANT  
FLOODING OF MODERATE SEVERITY OR HIGHER. PONDING ON ROADWAYS,  
PARTICULARLY IN URBAN, LOW LYING, OR POOR DRAINAGE AREAS COULD  
BECOME PROBLEMATIC FRIDAY NIGHT INTO SATURDAY.  
 

 
   
GYX WATCHES/WARNINGS/ADVISORIES
 
 
ME...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH SATURDAY  
EVENING FOR MEZ012.  
NH...FLOOD WATCH FROM 2 PM EDT THIS AFTERNOON THROUGH SATURDAY  
EVENING FOR NHZ003>013-015.  
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT SATURDAY FOR ANZ150-152-  
154.  
 

 
 

 
 
NEAR TERM UPDATE...PALMER  
NEAR / SHORT TERM...BARON  
LONG TERM...COMBS/EKSTER  
HYDROLOGY...BARON/JAMISON/PALMER  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab ME Page
The Nexlab NH Page Main Text Page