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Area Forecast Discussion
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000
FXUS61 KGYX 222110
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
410 PM EST MON DEC 22 2014

.SYNOPSIS...
AN WEAK ONSHORE FLOW WILL CONTINUE THROUGH TUESDAY. A SIGNIFICANT
LOW PRESSURE SYSTEM WILL MOVE ACROSS THE GREAT LAKES WEDNESDAY
INTO THURSDAY. THIS COULD BRING WINDY CONDITIONS AND THE
POTENTIAL FOR HEAVY RAIN AROUND CHRISTMAS EVE INTO EARLY CHRISTMAS
MORNING. ANOTHER LOW PRESSURE SYSTEM WILL APPROACH THE REGION LATE
IN THE WEEKEND POTENTIALLY BRINGING SOME WINTRY WEATHER.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A PERSISTENT LIGHT ONSHORE FLOW FROM THE EAST COMBINE WITH SOME
WEAK WAA OVERRUNNING ALOFT FROM THE SOUTHWEST WILL COMBINE TO
BRING PERIODS OF LIGHT PCPN TONIGHT.  

A WINTER WX ADVISORY HAS BEEN ISSUED FOR SOUTHWEST NH FOR SOME
VERY LIGHT SNOW OR MIXED PCPN TONIGHT INTO EARLY TUE BEFORE
CHANGING TO RAIN TOWARD MORNING AS THE BOUNDARY LAYER TEMPS WARM
BACK ABOVE FREEZING. ELSEWHERE ACROSS CENTRAL AND NORTHERN NH AND
WESTERN MAINE ANY LIGHT PCPN WILL BE IN THE FORM OF SNOW. TOWARD
AND ALONG THE COASTAL AREAS BOUNDARY LAYER TEMPS WILL BE MARGINAL
DUE TO THE ONSHORE FLOW SO THE PCPN MAY BE IN THE FORM OF LIGHT
RAIN.

USED A BLEND OF THE MODELS FOR POPS AND OVERNIGHT TEMPS. STAYED
WITH RFCQPF VALUES WHICH CONFIRMED ONLY VERY LIGHT AMOUNTS OF QPF
EXPECTED OVERNIGHT. 

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
OVER SOUTHERN AREAS OF NH AND ME, LOW LEVEL TEMPS WILL SLOWLY
WARM ABOVE FREEZING SO ANY AREAS OF LGT SNOW OR MIXED PCPN SHOULD
CONVERT TO RAIN AS THE DAY PROGRESSES. OVER NORTHERN AREAS, SOME
LIGHT SNOW WILL CONTINUE BUT NO ACCUMULATIONS EXPECTED. OF NOTE:
BUFKIT SHOWS NICELY THE VERY SHALLOW INVERSIONS ACROSS NH AND SRN
ME TUE MORNING BUT WITH TIME THEY GET WIPED OUT DURING THE DAY.
ALL AREAS CHANGE TO RAIN TUE NIGHT AS THE WAA ALOFT FROM THE SOUTH
AND SOUTHWEST CONTINUES WHILE AT THE SAME TIME THE LOW LEVEL
ONSHORE FLOW STRENGTHENS. QPF AMOUNTS WILL REMAIN LIGHT THROUGH
TUE NIGHT AS PER RFCQPF. STAYED CLOSE TO A SUPERBLEND OF MODELS
FOR TEMPS WHICH SEEMED TO APPEAR RATHER REPRESENTATIVE FOR THE
SCENARIO.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
THE WEDNESDAY THROUGH THURSDAY MORNING PERIOD CONTINUES TO LOOK
LIKE A WET ONE. COLD AIR DAMMING WILL LIKELY HOLD TOUGH AT THE SFC
ON WEDNESDAY...HOLDING TEMPERATURES IN THE 30S. HAVE LOWERED HIGHS
FOR WEDNESDAY IN STEP WITH MESOSCALE GUIDANCE BUT THEY MAY NEED
TO BE LOWERED A LITTLE MORE MOVING FORWARD. IN A NUTSHELL...A COLD
RAIN IS EXPECTED WEDNESDAY WITH SOME ICING POSSIBLE IN THE MORNING
ACROSS THE NORTHERN MOUNTAINS.

THE WARM FRONT TO OUT SOUTH LOOKS TO PUSH NORTHWARD WEDNESDAY
NIGHT AS A STRONG SHORT WAVE TROUGH APPROACHES FROM THE SOUTHWEST.
THE COLD SFC AIR WILL BE TOUGH TO DISLODGE BUT IT LOOKS LIKE THE
WARM FRONT SHOULD MAKE IT INTO SOUTHERN NH WEDNESDAY NIGHT...THEN
CONTINUE TO PUSH NORTH THURSDAY BEFORE COLD FRONT/OCCLUSION MOVES
THROUGH. IT/S POSSIBLE THAT MANCHESTER/NASHUA NH CORRIDOR COULD BE
55-60 DEGREES LATER WED NIGHT WHILE AT THE SAME TIME CONCORD IS IN
THE 30S. SHOULD BE A TIGHT GRADIENT. 

THE RAINFALL FROM THIS SYSTEM DOES NOT LOOK LIKE IT WILL BE AS
HEAVY AS WAS ADVERTISED BY THE MODELS THE PREVIOUS SEVERAL DAYS.
THIS LIKELY DUE TO THE ABSENCE OF A STRONG SOUTHEASTERLY INFLOW
BELT JUST ABOVE THE SFC. INSTEAD...IT/S MAINLY DEEP LAYER
SOUTHERLY/SOUTHWESTERLY FLOW JUST ABOVE THE BOUNDARY LAYER WHICH
SHOULD KEEP STORM TOTAL RAINFALL AMOUNTS IN THE 1-2.25 INCH
RANGE. THIS SHOULD KEEP ANY FLOODING PROBLEMS TO THE URBAN/POOR
DRAINAGE KIND...WITH THE RIVERS REMAINING OK. THE HEAVIEST
RAINFALL IS EXPECTED WED AFTERNOON INTO THU MORNING. A RUMBLE OF
THUNDER CANNOT BE RULED OUT AS MARGINAL INSTABILITY DEVELOPS ABOVE
THE COOL BOUNDARY LAYER.

WILL ALSO HAVE TO WATCH OUT FOR GUSTY WINDS LATE WED NIGHT AND THU
MORNING WHERE WE WARM SECTOR...AS THE LOW LEVEL JET COULD MIX
DOWN. THIS WOULD BE ESPECIALLY POSSIBLE IN CONVECTION.

OTHERWISE...FAIR WEATHER RETURNS THU AFTERNOON AND NIGHT. ECMWF
HAS BEEN ADVERTISING A SNOWSTORM LATE IN THE WEEKEND OVER THE LAST
FEW RUNS...SO WE/LL HAVE TO CONTINUE TO MONITOR THAT POTENTIAL.

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
SHORT TERM...MVFR CONDS EXPECTED TONIGHT THROUGH TUE AND MAY
BECOME IFR AT TIMES IN ANY LIGHT PCPN. CONDS TO BECOME WIDESPREAD
IFR CONDS TUE NIGHT.  

LONG TERM...EXTENDED PERIOD OF FLIGHT RESTRICTIONS WED INTO THU
MORNING. LOOK FOR IFR OR LOWER DURING THIS TIME. EXPECT
IMPROVEMENT TO VFR THU AFTERNOON...WHICH SHOULD HOLD THRU
SATURDAY.

&&

.MARINE...
SHORT TERM...WINDS WILL REMAIN BELOW SCA CRITERIA TONIGHT THROUGH
TUE NIGHT BUT THE CONTINUE EASTERLY FETCH WILL ALLOW SEAS TO BUILD
ABOVE 5 FT OVER THE OUTER WATERS BEGINNING THIS EVENING AND
CONTINUING THROUGH TUE NIGHT AS PER THE SWAN NAMSWAN GUID
SUGGESTS. 

LONG TERM...MODELS CONTINUE TO BACK OFF THE STRONG WINDS WED INTO
THU...BUT STILL A PERIOD OF GALES POSSIBLE IN THE S FLOW LATE WED
AND WED NIGHT...BUT MORE LKLY IN STRONG W FLOW THU INTO THU NIGHT.

&&

.HYDROLOGY...
MODELS CONTINUE TO BACK OFF ON RAINFALL TOTALS FOR
THE CHRISTMAS EVE/EARLY CHRISTMAS MORNING EVENT...BUT ARE STILL
AROUND 2 INCHES. IN ANY CASE...WHILE THE THREAT OF FLOODING IS
LOWER...IT STILL REMAINS A POSSIBILITY WED NIGHT INTO THU...MAINLY
THE URBAN AND POOR DRAINAGE VARIETY. RIVER FLOODING DOESN/T LOOK
LIKE A BIG THREAT AT THIS TIME SINCE IT LOOKS LIKE TEMPERATURES
WON/T GET UP HIGH ENOUGH IN THE MOUNTAINS TO ALLOW FOR SUBSTANTIAL
MELTING OF SNOW.

&&

.TIDES/COASTAL FLOODING...
ASTRONOMICAL TIDES ARE AT THEIR PEAK FOR THE MONTH. THIS...IN
COMBINATION WITH STRONG SOUTHERLY WINDS LATE WED INTO EARLY THU
WILL LIKELY ALLOW FOR SOME STORM SURGE. THERE IS SOME POTENTIAL
FOR MINOR COASTAL FLOODING OR SPLASH OVER AND BEACH EROSION AROUND
THE TIMES OF HIGH TIDE WED NIGHT INTO EARLY THU AFTERNOON.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 8 AM EST 
     TUESDAY FOR NHZ007-008-011-015.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 8 PM THIS EVENING 
     TO 6 AM EST WEDNESDAY FOR ANZ150-152-154.

&&

$$

LONG TERM...MLE
 



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