FXUS61 KGYX 050304
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
1004 PM EST FRI DEC 4 2009
.SYNOPSIS...
LOW PRESSURE WILL DEVELOP IN THE GULF OF MEXICO TONIGHT. IT WILL
MOVE NORTHEAST...REACHING THE MID ATLANTIC COASTLINE LATE SATURDAY
AFTERNOON...BEFORE CROSSING EAST OF THE GULF OF MAINE SATURDAY
NIGHT. HIGH PRESSURE WILL BUILD SOUTH OF THE REGION SUNDAY. A WEAK
WEATHER DISTURBANCE WILL TRACK OVER NORTHERN NEW ENGLAND MONDAY.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
MINOR MODIFICATIONS TO THE GRIDS FOR THE OVERNIGHT...JUST FOR
TEMP/SKY...NOTHING TO RE-ISSUE THE ZONES FOR. LOCAL TEMP
ADJUSTMENTS TO REFLECT PARTIAL RAD COOLING...AND SKY ADJ JUST TO
SHOW LONGER PERIOD OF NON-OPAQUE CIRRUS...MOSTLY THRU THE WHOLE
NIGHT ACROSS CWA. ANY OTHER EFFECTS OF THE APPROACHING SYSTEM WILL
HOLD OFF UNTIL AROUND MIDDAY SAT.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
10 PM UPDATE...QUICK LOOK AT 00Z NAM SHOWS SFC LOW TRACKING JUST
OUTSIDE THE BENCHMARK...MORE IN LINE WITH 12Z GFS ENSEMBLE AND 12Z
RGEM...AND ITS QPF IS CUT ALMOST IN HALF...MAXING AROUND A THIRD
OF AN INCH IN SE NH AND COASTAL ME S OF CASCO BAY. THIS TREND WAS
SEEN IN THE 18Z NAM AND GFS...BUT CONFIDENCE IN THE OFF-HOUR RUNS
NOT AS HIGH. LOOKS LIKE ANY PRECIP WILL COME FROM N EDGE OF MID-
LVL DEFORMATION BAND JUST S OF CWA. NO CHANGES ATTM...WILL LET
MID- SHIFT LOOK OVER ALL 00Z GUIDANCE.
PREV DISC...THIS SYSTEM WILL MOVE QUICKLY NORTHEAST SATURDAY.
MODELS CONTINUE TO HAVE PROBLEMS RESOLVING TRACK OF THE LOW.
LATEST 12Z RUNS SUGGEST A MORE WESTWARD TRACK...ESPECIALLY THE
WRF. GFS AND EURO ARE FURTHER OUT TO SEA. WILL COMPROMISE WITH
THESE TRACKS. THIS WILL BRING PRECIPITATION INTO SOUTHERNMOST
MAINE AND NEW HAMPSHIRE LATE IN THE DAY SATURDAY.
PTYPE IS THE QUESTION. DURING THE MID/LATE AFTERNOON HOURS...THE
BOUNDARY LAYER WILL STILL BE ON THE MILD SIDE. HOWEVER...DECREASING
DEW POINTS MAY LEAD TO SOME EVAPORATIONAL COOLING. WITH THE
PRECIPITATION EXPECTED TO BE INITIALLY LIGHT AT THE
ONSET - WITH LITTLE VERTICAL MOTION...EXPECT A MIX OF SNOW AND
RAIN ALONG THE COAST...WITH ALL SNOW INLAND. THE PRECIPITATION
SHOULD TREND TOWARDS SNOW HOWEVER...AS WE HEAD INTO NIGHTFALL.
MAV/MET MOS VERY CLOSE. DROPPED SATURDAY'S HIGHS DOWN A DEGREE OR
TWO AS MODEL RUNS HAVE BEEN CONSISTENTLY TRENDING COLDER EACH DAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
RATHER COMPLEX FORECAST FOR SAT NIGHT AS ECM/GFS NOW FURTHER W AND
SLOWER WITH DEVELOPMENT OF COASTAL LOW MORE IN LINE WITH PRIOR
RUNS OF THE NAM. QPF AMTS FROM NAM ARE .5-.75 OVER SERN NH AND
SWRN CSTAL ME WHILE GENERALLY .25-.50 AMTS OFF THE GFS. INITIALLY
ANY RN OR MIX SHOULD QUICKLY CHG TO SNOW DUE TO EVAPO COOLING AND
CAA ON NLY LOW LEVEL WINDS. RATHER INTERESTING WITH THIS SYSTEM IS
ITS POINT OF ORIGIN WITH A LARGE BUNDLE OF ENERGY/MSTR...CONSIDERING
ITS DVLPMNT IN THE LOW LATITIUDES MODELS MAY HAVE A TUFF TIME
BRINGING IT OUT OF THE GULF OF MEXICO TO THE SERN US WITH A PROPER TRACK.
VERY LOW CONFIDENCE ON TRACK WHICH WILL BE CRITICAL...IF TREND
ENDS UP FURTHER W A DECENT SNOWFALL WILL OCCUR BUT IF IT ENDS UP A
TAD FURTHER E THEN LESSER AMTS WILL ENSUE. A WINTER STM WATCH MAY
BE NEEDED FOR XTRM SERN NH/SWRN ME FOR SAT NIGHT BUT DUE TO
UNCERTAINTY WILL HOLD OFF AT THIS TIME.
THE SYSTEM WILL EXIT QUICKLY BY SUN MRNG FOLLOWED BY HIGH PRES AND
COLDER TEMPS. ON LATE MON/MON NGT A FAST MOVING S/WV WITH SOME
WEAK OVERUNNING LGT SNOWS EXPECTED BUT WILL ALSO QUICKLY EXIT BY
TUES MRNG. ANOTHER SIGNIFICANT SYSTEM IS EXPECTED FOR LATER WED
AND WED NIGHT AS A STRONG STORM SYSTEM IS EXPECTED TO TRACK TO OUR
W BUT IN ADVANCE A STG WAA PATTERN WILL OVERRIDE THE ARCTIC DOME
IN PLACE OVER NRN NEW ENGL. SNOW WILL OVERSPREAD ME/NH LATE WED
BUT THEN PTYPE WILL BECOME A MIX AND PSBLY CHG TO FRZG RN OVER THE
SOME AREAS. COLDER AND DRIER RETURNS FOR THE LATTER PART OF THE
WEEK.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...CONDITIONS WILL BE VFR FOR TONIGHT AND SATURDAY
MORNING. LATER SATURDAY AFTERNOON...CEILING/VSBYS WILL BEGIN TO
LOWER IN A RAIN/SNOW MIX...TOWARDS MVFR AND IFR BY SAT EVENING.
LONG TERM...IFR TO LIFR CONDS EXPECTED SAT NIGHT IN
SNOW...BECOMING VFR EARLY SUN AND CONTINUING INTO EARLY MON. BY
LATE MON AND MON NGT CONDS WILL LOWER TO MVFR OR IFR AS AN UPPER
TROF MOVES CROSSES THE AREA SPREADING SOME LIGHT SNOW AND LOWER
CIGS...CONDS WILL IMPROVE TO VFR ONCE AGAIN ON TUES.
&&
.MARINE...
SHORT TERM...NO FLAGS. AWAITING NEXT SYSTEM IN THE LONG TERM.
LONG TERM...LATEST INDICATIONS ARE THAT THE OFFSHORE STORM WILL
TRACK CLOSER TO THE WATERS MEANING WITH IT STONGER WINDS ARE
EXPECTED THAN EARLIER THOUGHT SO A GALE WATCH HAS BEEN ISSUED FOR
SAT NGT. THE LOW QUICKLY MOVES E ON SUN WITH WINDS DIMINISHING IN
ITS WAKE FOLLOWED BY HIGH PRES FOR MON.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR
ANZ150-152-154.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...CEMPA
LONG TERM...
AVIATION...
MARINE...
