AREA FORECAST DISCUSSION
NWS GRAY ME
AFDGYX 950 AM EST SAT FEB 21 2004
.UPDATE...
AN UPDATE WILL COME OUT THIS MORNING...MAINLY TO ADDRESS TEMPERATURE
TRENDS...PRECIPITATION TYPES...AND ASSESS THE NEED FOR CHANGES TO
THE ADVISORIES.
CURRENTLY...WARM AIR ADVECTION PRECIPITATION SPOTTY ACROSS THE
FORECAST AREA. THE 12Z GYX SOUNDING SHOWED THE AIRMASS BELOW
FREEZING. AN ACARS SOUNDING FROM MHT AT 13Z SHOWED ABOUT THE SAME
THING. SINCE THE DEEP CLOUD PROCESSES IN THE WARM AIR ADVECTION
ARE SPOTTY...IN PLACES WHERE THE PRECIPITATION COMES DOWN LIGHTLY IT
IS SLEET OR LIGHT FREEZING RAIN. IN OTHER AREAS...SNOWFLAKES ARE
SURVIVING TO THE SURFACE. SNOWFALL AMOUNTS HAVE BEEN 2 INCHES OR
LESS FOR THE MOST PART SO FAR.
AT 14Z...TEMPERATURES WERE ABOVE FREEZING OVER A LARGE AREA OF
SOUTHEAST NEW HAMPSHIRE AND THE SOUTHERN THIRD OF MAINE. WINDS ARE
EAST TO SOUTHEAST.
FOR THE SHORT TERM...THE MAIN CONCERNS ARE TEMPERATURES AND
PRECIPITATION TYPE. THE AWIPS RADAR MOSAIC SHOWS AN AREA OF
PRECIPITATION MOVING NORTHEAST TOWARD THE FORECAST AREA...WITH THE
BEST VERTICAL MOTION HEADED TOWARD THE NORTHERN ZONES. FURTHER
SOUTH...IT APPEARS AS THOUGH THE PRECIPITATION WILL BE FAIRLY LIGHT
THROUGH 21Z.
FOR NORTHERN ZONES...THE PRECIPITATION SHOULD FALL IN THE FORM OF
SNOW (POSSIBLY MIXED WITH LIGHT FREEZING RAIN AT TIMES). FURTHER
SOUTH...IN THE SPOTTIER PRECIPITATION...THE TYPE WILL REMAIN
MIXED. WILL CONTINUE THE FAIRLY HIGH CHANCE OF PRECIPITATION AND
MENTION AS OCCASIONAL. WHILE THERE MAY BE SOME FREEZING RAIN IN
SPOTS THIS MORNING AND EARLY THIS AFTERNOON ACROSS PORTIONS OF
INTERIOR SOUTHERN NEW HAMPSHIRE AND INTERIOR SOUTHWEST MAINE...IT
SHOULD BECOME INCREASINGLY SPARSE.
THE SURFACE LOW DEVELOPING SOUTH OF LONG ISLAND NEW YORK THIS
MORNING WILL BECOME THE MAIN FORECAST PROBLEM LATE THIS AFTERNOON
AND TONIGHT. THIS SHOULD CUT OFF THE INFLOW OF WARM AIR AND CHANGE
THE PRECIPITATION BACK TO SNOW. FOR NOW...THE AMOUNTS SHOULD
REMAIN BELOW CRITERIA FOR MUCH OF SOUTHERN NEW HAMPSHIRE AND
SOUTHWEST MAINE. WHILE THE FINAL DECISION WILL BE MADE AFTER
EVALUATING 1000 AM OBSERVATIONS...THE ADVISORY WILL PROBABLY BE
DROPPED FOR MUCH OF WEST CENTRAL AND SOUTHEAST NEW HAMPSHIRE...AS
WELL AS SOUTHWEST MAINE.
FURTHER EAST...THE ADVISORY WILL REMAIN IN PLACE. THERE COULD BE
ACCUMULATING SNOW HERE LATER THIS AFTERNOON AND TONIGHT. THE
TONIGHT PART OF THE FORECAST MAY NEED TO BE ADJUSTED...BUT MUCH OF
THIS WILL BE DOME THIS AFTERNOON. THE ADVISORY WILL REMAIN IN
PLACE FOR THE FOOTHILLS AND MOUNTAINS...AS A MENTION OF MIXED
PRECIPITATION WILL BE MAINTAINED. THE SNOW AMOUNTS WILL BE DROPPED
A BIT FOR THE NEW HAMPSHIRE PORTION OF THE REGION.
NO OTHER CHANGES AT THIS TIME. AS MENTIONED EARLIER...THE TONIGHT
FORECAST WILL HAVE TO BE REEVALUATED AS THE DEVELOPING LOW AND LIFT
WITH IT MAY CAUSE ADDITIONAL ACCUMULATIONS FOR EASTERN ZONES
TONIGHT. &&
.UPDATED MARINE...
WINDS AND SEAS HAVE BEEN BUMPED UP TO MATCH OBSERVATIONS AHEAD OF
THE LOW. SEAS WERE INCREASED FOR TONIGHT AS WELL TO ACCOUNT FOR THE
EASTERLY FLOW.
&&
.PREVIOUS DISCUSSION...
AN AREA OF LOW PRESSURE CENTERED OVER SOUTHERN ONTARIO WILL WEAKEN
TODAY AS A SECONDARY AREA OF LOW PRESSURE DEVELOPS OVER SOUTHERN
NEW ENGLAND. WARMER AIR MOVING NORTHWARD BOTH ALOFT AND AT GROUND
LEVEL WILL RESULT IN THE SNOW MIXING WITH OR CHANGING TO
SLEET...FREEZING RAIN...AND RAIN ACROSS SOUTHERN AND CENTRAL
PORTIONS OF THE GRAY MAINE FORECAST AREA. OVER THE FOOTHILLS AND
MOUNTAINS PRECIPITATION WILL REMAIN ALL SNOW. SNOW ACCUMULATIONS
WILL RANGE FROM 3 TO 6 INCHES IN THE MOUNTAINS AND FOOTHILLS TO LESS
THAN 2 INCHES ALONG THE SOUTHWEST COAST. THE PRECIPITATION WILL
TAPER OFF THIS AFTERNOON AS DRIER AIR MOVES IN ALOFT.
LOW PRESSURE WILL DEVELOP IN THE UPPER ATMOSPHERE TONIGHT AS THE
SURFACE LOW PRESSURE SYSTEM MOVES INTO THE GULF OF MAINE. THE
COMBINATION OF LOW AT THE SURFACE AND THE LOW ALOFT WILL BRING SNOW
SHOWERS TO THE MOUNTAINS AND FOOTHILLS WITH SCATTERED SNOW SHOWERS
ELSEWHERE.
THE SECONDARY AREA OF LOW PRESSURE WILL MOVE SLOWLY NORTHEAST
REACHING NOVA SCOTIA SUNDAY AFTERNOON AND THEN MOVE EAST OF NOVA
SCOTIA BY SUNDAY NIGHT. THIS WILL BRING AN END TO MOST OF THE SNOW
SHOWERS HOWEVER SOME LINGERING SNOW SHOWERS ARE POSSIBLE IN THE
MOUNTAINS.
A WEAK RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA MONDAY INTO
WEDNESDAY BRINGING DRY WEATHER AND NEAR NORMAL TEMPERATURES. THE
ONLY THREAT OF PRECIPITATION WILL BE JUST A CHANCE OF SNOW SHOWERS
IN THE MOUNTAINS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY TODAY MEZ007>009-012>014
MEZ020>022-025>028.
SCA.
NH...WINTER WEATHER ADVISORY TODAY NHZ001>004.
SCA.
$$
HAYES