FXUS61 KGYX 291425
AFDGYX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
925 AM EST SUN NOV 29 2009
.SYNOPSIS...
A WEAK RIDGE OF HIGH PRESSURE WILL MOVE ACROSS THE AREA
TODAY...PROVIDING A DRY AND MAINLY SUNNY DAY. LOW PRESSURE WITH A
TRAILING COLD FRONT WILL MOVE NORTHEAST ALONG THE ST LAWRENCE
VALLEY LATER TONIGHT AND INTO THE MARITIMES BY LATER
MONDAY...BRINGING SOME PRECIPITATION WITH IT...IN THE FORM OF A
MIXED BAG IN THE MOUNTAINS...AND RAIN SHOWERS EVERYWHERE BETWEEN
THE MOUNTAINS AND THE COAST. HIGH PRESSURE WILL BUILD ACROSS THE
AREA TUESDAY AND WEDNESDAY. ANOTHER COASTAL STORM MAY AFFECT THE
AREA LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MINOR UPDATE TO FORECAST...OF WHICH MOST SIGNIFICANT CHANGE WAS TO
KEEP SKIES CLEARER LONGER INTO THE AFTERNOON AND EVENING.
OTHERWISE...JUST SOME MINOR TEMP/WIND ADJUSTMENTS MADE THROUGH
THIS EVENING. STILL ON TRACK FOR A SEASONABLY MILD AND MAINLY SUNNY
DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM MONDAY/...
IN ADVANCE OF THE SFC LOW MOVING E ACROSS THE ST LAWRENCE VLY
TNGT...A WAA PATTERN WILL DEVELOP AND CAUSE SOME LGT PCPN TO
BREAK OUT ACROSS OUR NRN AREAS OF NH AND WRN ME. INITIALLY SFC
TEMPS WILL BE PLENTY COLD WITH ONLY MARGINALLY COLD AIR ALFT BUT
EVAPO COOLING SHOULD OFFSET ANY WARM LYRS ABV SFC AT THE ONSET. AS
TIME WEARS ON LATER MON NGT 1000-850 THICKNESSES APPEAR TO BECOME
TOO WARM FOR SNOW AND PTYPE WILL BE A MIX WITH EVEN SOME FRZG RN
PSBL IN THE FOOTHILLS. QPF AMTS TO BE VERY LGT FM 06Z-12Z MON SO
ONLY LGT ACCUMS OF SNOW AND MIX EXPECTED. DAY SHIFT MAY NEED TO
CONSIDER A WINTER WX ADVSRY FOR THE NRN MOST AREAS FOR AFT 06Z IN
THE MAINE PORTION OF THE CWA. STAYED CLOSE TO MET TEMPS FOR
OVERNIGHT LOWS.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
SHORTWAVE WILL PIVOT THROUGH THE NORTHEAST ON MONDAY PUSHING A COLD
FRONT THROUGH AROUND MIDDAY. HAVE DEPICTED THE HIGH TEMPERATURES
OCCURRING IN THE MORNING WITH DECREASING READINGS THEREAFTER. SNOW
WILL BE CONFINED TO THE HIGHER ELEVATIONS AS TEMPERATURES ALONG
THE COAST AND INLAND LOOK TOO WARM. QPF AMOUNTS WILL GENERALLY BE
LESS THAN A QUARTER INCH WITH HIGHER AMOUNTS TO THE NORTH. COLD AIR
DRAINS INTO THE ENTIRE CWA SOON AFTER THE COLD FRONT AND THE BULK
OF THE PRECIP MOVE OFFSHORE. UPSLOPE SNOW SHOWERS WILL CONTINUE IN
THE HIGHER TERRAIN TUE AND WED AS SURFACE WINDS MAINTAIN A WESTERLY
COMPONENT.
THE NEXT SYSTEM OF CONSEQUENCE WILL BE THE COASTAL LOW WHICH
APPROACHES FROM THE SSW WED NIGHT INTO THU. THE MEAN UPPER LEVEL
TROF AXIS WILL SWING EAST AS A SOUTHERN STREAM SHORTWAVE MOVES UP
THE COAST. AS THIS OCCURS...THE SURFACE LOW WILL UNDERGO EXPLOSIVE
CYCLOGENESIS. THE GFS AND ECMWF ARE GOOD AGREEMENT AND BOTH SHOW
THE LOW PASSING JUST OFF THE NEW ENGLAND COAST. DEPENDING ON WHERE
THE SURFACE LOW DOES TRACK...IMPRESSIVE DYNAMICS WILL BE PRESENT
TO SUPPORT MESOSCALE PRECIP BANDS IN THE FORM OF RAIN AND SNOW.
ISENTROPIC LIFT SHUTS OFF QUICKLY FRI...ENDING THE BULK OF THE
PRECIP ACROSS THE AREA...HOWEVER MORE OROGRAPHIC SNOW SHOWERS ARE
IN STORE FOR THE NORTHERN ZONES OVER THE WEEKEND. THE TRAJECTORY
OF NEXT WEEK'S AIRMASS COMES FROM NORTHERN CANADA...AND MODELS
LIKELY DO NOT HAVE A HANDLE ON THE DEPTH OF THE COLD AIR. AS A
RESULT WENT SLIGHTLY BELOW GUIDANCE FOR TEMPS NEAR THE END OF THE
FORECAST.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...VFR TODAY. AFT 06Z TNGT SOME OVERUNNING LGT MIXD
PCPN WILL OVERSPREAD NRN NH AND THE WRN MTNS...HOWEVER TERMINALS
TO REMAIN VFR THROUGH MOST OF TONIGHT...WITH POSSIBLE EXCEPTION OF
KLEB WHICH COULD SEE SOME MVFR CIGS LATE TONIGHT.
LONG TERM...ALL TERMINALS WILL LOWER TO MVFR CONDITIONS AS RAIN
AND FOG SPREAD ACROSS THE AREA MONDAY. LEB AND CON WILL SEE A
BETTER CHANCE FOR SNOW AND IFR CIGS. CONDITIONS WILL IMPROVE LATE
MON NIGHT.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...NO FLAGS NEEDED. WINDS/SEAS TO
CONTINUE TO DIMINISH TODAY INTO TNGT.
LONG TERM...WINDS WILL REACH SCA CRITERIA MON MORNING INTO TUE
AHEAD OF AND BEHIND A FRONTAL PASSAGE. WINDS WILL INCREASE TO AT
LEAST SCA CRITERIA THU AS A COASTAL LOW APPROACHES.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...CEMPA
