Area Forecast Discussion
Issued by NWS Portland, ME

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KGYX 250937 AFDGYX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAY ME 437 AM EST SUN JAN 25 2015 .SYNOPSIS... A COLD FRONT WILL MOVE ACROSS THE WATERS THIS MORNING. LOW PRESSURE WILL BEGIN TO DEVELOP OFF THE MID ATLANTIC COAST ON MONDAY THEN RAPIDLY DEVELOP AS IT MOVES NORTHEASTWARD TO JUST SOUTH OF NANTUCKET MASSACHUSETTS ON TUESDAY. THE LOW WILL LINGER AROUND THROUGH WEDNESDAY BRINGING A SIGNIFICANT SNOWFALL TO OUR REGION. THERE IS ALSO THE POTENTIAL FOR ANOTHER STORM LATE WEEK OR EARLY IN THE WEEKEND BUT CONFIDENCE IS LOW AT THIS TIME. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A COLD FRONT WILL MOVE ACROSS THE REGION THIS MORNING BRINGING A PERIOD OF CLOUDS AND ALSO A CHANCE OF SNOW SHOWERS...MAINLY ACROSS THE INTERIOR. A FEW HEAVIER SQUALLS MAY BE EMBEDDED. THEREAFTER...JUST COLD AND WINDY FOR THE BALANCE OF THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... COLD NIGHT ON TAP TONIGHT AS HIGH PRESSURE BUILDS INTO THE REGION. WIND CHILLS MAY APPROACH 20 BELOW ZERO FOR A TIME ACROSS FAR NORTHERN REACHES OF OUR CWA. HOWEVER...ELECTED TO NOT ISSUE A WIND CHILL ADVISORY AT THIS TIME DUE TO SPORADIC COVERAGE...MAINLY AT HIGHER ELEVATIONS. INCREASING HIGH CLOUDS ON MONDAY AS STORM SYSTEM WELL TO OUR SOUTH STARTS TO GET UNDERWAY. IT SHOULD REMAIN DRY THROUGHOUT THE DAY. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... MAIN FOCUS OF THE EXTENDED IS ON STRONG LOW PRES FORECAST TO DEVELOP S OF NEW ENGLAND MON INTO TUE. STRONG S/WV TROF EXITING THE CANADIAN PRAIRIES TODAY WILL DEPART THE MID ATLANTIC COAST BY MON AFTERNOON. UPON REACHING THE RICH BAROCLINICITY OFFERED BY THE WARM ATLANTIC...THIS LOW PRES WILL RAPIDLY DEVELOP S OF NEW ENGLAND. DROPPING SOME 20 MB IN 24 HOURS THIS WILL BRING SIGNIFICANT IMPACTS TO THE REGION. THE INITIAL S/WV IS FORECAST TO DIG S TOWARDS THE CAROLINAS. THIS ALLOWS TIME FOR THE UPSTREAM KICKER TO CATCH UP AND PHASE WITH THE DEVELOPING SYSTEM LATE MON. THIS WILL ACT TO SLOW DOWN...STALL...AND PERHAPS LOOP THE LOW PRES S OF NEW ENGLAND...PROLONGING IMPACTS AS WELL. CONSIDERING HOW DYNAMIC THE SYSTEM IS...MODEL CLUSTERING ON QPF IS FAIRLY TIGHT. DETERMINISTIC MODELS ALL BRING AT LEAST 0.60 INCHES QPF TO THE INTERNATIONAL BORDER. GEFS AND ECMWF EPS ALSO BRING THE HALF INCH QPF LINE N OF THE BORDER. THIS IS A ROBUST SIGNAL FOR SOME MODERATE TO HEAVY ACCUMULATIONS THRU THE ENTIRE FORECAST AREA. DURING THE RAPID DEEPENING PHASE OF THE STORM...THE FIRST HALF OF TUE...STRONG ELY LOW LEVEL JET WILL DEVELOP. GEFS STANDARDIZED ANOMALIES ACTUALLY REACH -6 STANDARD DEVIATIONS FOR THE U WIND. THIS TYPE OF MAGNITUDE FOR THE LOW LEVEL JET WILL USUALLY FOCUS SIGNIFICANT ENHANCEMENT ALONG THE ERN SLOPES...WITH DOWNSLOPE PRECIP SHADOWING TO THE NW OF THE HIGH TERRAIN. SO SOME QPF MAY BE LOST TO THIS FOR PARTS OF GRAFTON AND COOS COUNTIES...BUT ENOUGH OF THOSE ZONES SEE HIGH ENOUGH QPF TO WARRANT A WINTER STORM WATCH FOR ALL ZONES IN THE FORECAST AREA. LOW PRES WILL BE OCCLUDING AT SOME POINT DURING THIS PERIOD...SO DETAILS ARE HARD TO PIN DOWN WITHOUT HAVING A BETTER IDEA OF EXACTLY WHEN AND WHERE THIS OCCURS. BUT IN GENERAL...A HEAVY BAND OF SN WILL LIFT N THRU THE AREA WITH THE INITIAL BURST OF INTENSE WAA ALOFT. THIS WILL BE TUE MORNING...IMPACTING THE COMMUTE...AND SNWFL MAY REACH 1 INCH PER HOURS AT TIMES. ONCE WAA LIFTS N OF THE AREA THE QUESTIONS BECOMES WHETHER ANY DEFORMATION CAN LINGER OVER THE AREA AND IF WE CAN MAINTAIN SATURATION ALOFT TO CONTINUE ACCUMULATING SNWFL. MODEL HEIGHT FIELDS SUGGEST A BACK BENT WARM FNT ALOFT...AND STRONG DYNAMICS ASSOCIATED WITH FEATURES LIKE THIS CAN THROW A WRENCH IF YOU TRY AND GET TOO SPECIFIC AT THIS TIME RANGE. TUE NIGHT INTO WED UPPER LOW WILL DRIFT THRU THE GULF OF ME...AND LIGHT SNWFL WILL CONTINUE THRU THIS TIME PERIOD. THE LAST MAJOR CONCERN IS THE WIND FORECAST. STRONG..BUT WEAKENING...LOW LEVEL JET WILL BE LIFTING N ACROSS THE AREA TUE. GFS FORECAST IS MOST AGGRESSIVE WITH MIXING...BUT DEEP COLD AIR IN PLACE AHEAD OF THE STORM SUGGESTS THAT SIGNIFICANT MIXING IS POSSIBLE. IF MIXING TO ABOUT H9 IS ASSUMED...A PERIOD OF 40 TO 45 KT GUSTS IS POSSIBLE ALONG THE COAST TUE. HOWEVER CONFIDENCE WAS TOO LOW TO GO WITH ANY BLIZZARD HEADLINES AT THIS TIME. THAT BEING SAID...POTENTIAL IS THERE FOR AT LEAST NEAR-BLIZZARD OR WHITEOUT CONDITIONS DURING THE DAY TUE. THERE IS AT LEAST ONE MORE MODEL CYCLE TO ANALYZE TO ASSESS ANY TRENDS IN THIS WIND FORECAST FOR ANY POSSIBLE UPGRADES TO THE WATCH HEADLINES. PUTTING ALL THIS INFORMATION TOGETHER YIELDS A WIDESPREAD DOUBLE DIGIT SNWFL FOR THE AREA. BASED ON HEIGHT FIELDS...WINDS ALOFT...AND EXPECTED QPF ENHANCEMENT...HIGHEST AMOUNTS LOOK LIKELY ACROSS SRN NH AND ESPECIALLY THE MONADNOCKS. BEYOND THIS STORM SYSTEM A MUTLI-MODEL CONSENSUS WAS USED THRU THE REST OF THE EXTENDED. THERE WAS A FAIR AMOUNT OF AGREEMENT...THOUGH ENOUGH TIMING DIFFERENCE EXIST TO MAKE NAILING DOWN EXACT WINDOWS FOR THE NEXT STORM SYSTEMS DIFFICULT. HOWEVER BOTH THE ECMWF AND GFS APPEAR FAVORABLE FOR SNWFL LOVERS THRU THE END OF JAN...OFFERING ADDITIONAL CHANCES TO BOOKEND THE WEEKEND. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... SHORT TERM...VFR TODAY WITH SFC WIND GUSTS AROUND 25 KT. VFR TONIGHT AND MONDAY WITH LIGHTER WINDS AS HIGH PRESSURE MOVES INTO THE AREA. LONG TERM...HIGH CONFIDENCE IN A PERIOD OF IFR AND LOWER CONDITIONS BEGINNING MON NIGHT THRU TUE...AS COASTAL LOW PRES SPREADS SNWFL ACROSS THE AREA. HEAVY SNWFL AND WIDESPREAD IFR OR LOWER CONDITIONS WIND DOWN TUE EVENING...BUT SN LINGERS INTO WED MORNING WITH SCT IFR CONDITIONS POSSIBLE. COASTAL TERMINALS MAY SEE NE GUSTS NEAR 30 KTS DURING THE DAY TUE. && .MARINE... SHORT TERM...SCA FOR THE BAYS AND GALE THE OCEAN WATERS FOR TODAY AS CAA IN THE WAKE OF A COLD FRONT SHOULD BE STRONG. WINDS AND SEAS DIMINISH TONIGHT AND MONDAY AS HIGH PRESSURE BUILDS OVER THE WATERS. LONG TERM...STRONG LOW PRES S OF NEW ENGLAND WILL LIKELY BRING A PERIOD OF STORM FORCE WIND GUSTS TO THE OUTER WATERS TUE INTO TUE NIGHT. GALES LIKELY FOR THE BAYS DURING THIS TIME...WITH A LOW PROB OF STORM FORCE GUSTS THERE AS WELL. && .COASTAL FLOODING... HIGHEST TIDES EARLY TUE MORNING WILL LIKELY OCCUR PRIOR TO STRONGEST WINDS AND WAVE ACTION. HOWEVER DEPENDING ON STRENGTH AND DURATION OF NE FLOW...MINOR OR NEAR-MINOR FLOODING IS POSSIBLE. GIVEN THE HIGH SEAS EXPECTED...SPLASH OVER AND EROSION LOOKS LIKELY...ESPECIALLY S OF PORTLAND. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...WINTER STORM WATCH FROM MONDAY EVENING THROUGH LATE TUESDAY NIGHT FOR MEZ007>009-012>014-018>028. NH...WINTER STORM WATCH FROM MONDAY EVENING THROUGH LATE TUESDAY NIGHT FOR NHZ001>015. MARINE...GALE WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY EVENING FOR ANZ151-153. SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR ANZ151- 153. STORM WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY EVENING FOR ANZ150-152-154. GALE WARNING UNTIL 7 PM EST THIS EVENING FOR ANZ150-152-154. && $$ NEAR TERM...EKSTER SHORT TERM...EKSTER LONG TERM...LEGRO

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.