FXUS61 KALY 242353 PAA
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
644 PM EST THU DEC 24 2009
.SYNOPSIS...
CANADIAN HIGH PRESSURE WILL SHIFT EASTWARD ACROSS THE REGION AND
TONIGHT BUT WILL DOMINATE OUR WEATHER INTO FRIDAY. A STRONG LOW
PRESSURE SYSTEM WILL MOVE NORTH FROM THE SOUTHERN PLAINS TOWARD THE
WESTERN GREAT LAKES INTO THIS WEEKEND WITH ITS ASSOCIATED FRONTAL
BOUNDARY MOVING TOWARD OUR REGION. A SECONDARY AREA LOW PRESSURE IS
EXPECTED TO DEVELOP ALONG THIS BOUNDARY SATURDAY. THIS SCENARIO WILL
BRING MIXED PRECIPITATION TO THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
THE BIG CHALLENGE INTO THIS IS WHEN (AND IF) THE REMAINING CLOUD
DECK WILL ERODE. THE CLOUDS HAVE ERODE ACROSS MUCH OF THE
ADIRONDACKS PARK AND MOST OTHER PLACES ACROSS OUR COUNTY WARNING
AREA (CWA). HOWEVER...CLOUDS CONTINUE TO HOLD TOUGH ACROSS
WASHINGTON COUNTY...IMMEDIATE CAPITAL DISTRICT AND THE MOHAWK
VALLEY. SATELLITE IMAGERY SUGGEST THE CLOUD SHIELD SLOWLY ERODING
SOME MORE. THE CONCERN IS HOWEVER...IF THE CLOUDS COULD REFORM LATER
ON THIS EVENING. BASED ON MODEL SOUNDINGS...CLOUDS COULD REFORM
SOMEWHAT UNDERNEATH THE SUBSIDENCE INVERSION. WE ARE LEANING IN THAT
DIRECTION FOR TONIGHT. THEREFORE WE HAVE LEANED WITH THE WARM MET
VALUES BUT THE CLOUDS NEED TO BE MONITORED. IF THEY
DISSIPATE...TEMPERATURES WOULD LIKELY GO CLOSE TO THE COLDER MAV
GUIDANCE AND WE MIGHT EVEN SEE A LITTLE FOG FORMING.
SFC HIGH PRESSURE CONTINUES TO RIDGE IN FROM SOUTH OF HUDSON BAY.
THIS HIGH HAS BEEN IN THIS VICINITY FOR THE PAST WEEK...AND WILL
CONTINUE TO RESIDE IN THIS AREA THROUGH EARLY FRIDAY. THE DIFFERENCE
IS NOW THIS ANTICYCLONE IS SHIPPING IN CANADIAN MARINE AIR (AS
OPPOSED TO CONTINENTAL AIR) OUR WAY. THIS HIGH PRESSURE WILL SLOWLY
RETREAT INTO THE CANADIAN MARITIMES ON FRIDAY NIGHT. AS IT DOES
SO...IT WILL ALLOW ENERGY FROM THE HUGE MID WEST STORM...TO BEGIN TO
MOVE INTO THE REGION. IT LOOKS AS IF IT WILL REMAIN DRY ALL DAY ON
CHRISTMAS DAY. ANY PARTIAL CLEARING WILL BE FOLLOWED BY INCREASING
HIGH CLOUDS BY LATE IN THE DAY.
WITH THIS MARINE AIR IN PLACE...HIGH TEMPERATURES ON FRIDAY LOOK TO
BE MAINLY IN THE 30S EVERYWHERE ACROSS THE REGION. THIS VALUES ARE
CLOSE TO SEASONABLE NORMALS...EXCEPT A LITTLE HIGHER ACROSS THE
MOUNTAINS.
THEN...AS A LARGE AREA OF VORTICITY FROM THE LARGE STORM AS WELL AS
ITS ASSOCIATED WARM FRONT APPROACH THE REGION FRIDAY NIGHT...THE
THREAT FOR PRECIPITATION WILL INCREASE. AT THE SAME TIME
HOWEVER...RIDGING ALOFT WILL SERVE TO INHIBIT MOISTURE FROM
OVERSPREADING THE REGION. THEREFORE...IT LOOKS AS IF THE TIMING OF
THE PRECIPITATION WILL BE SLOWED DOWN A BIT...PROBABLY NOT REACHING
OUR EASTERN AREAS OF OUR CWA UNTIL LATE FRIDAY NIGHT OR AROUND 12Z
SATURDAY.
WITH PLENTY OF COLD AIR IN PLACE INITIALLY...THIS PRECIPITATION WILL
LIKELY START OUT AS A LITTLE SNOW OR SLEET. ANY WARMING LAYERS ABOVE
FREEZING WILL LIKELY BRIEFLY COOL BACK BELOW FREEZING DUE TO
EVAPORATIVE COOLING WITH ONSET OF PRECIPITATION. HOWEVER...AN
INCREASING LOW LEVEL JET OUT OF THE SOUTHEAST WILL BRING A WARM NOSE
ACROSS MOST OF OUR REGION ON SATURDAY. THIS SHOULD CHANGE ANY SLEET
AND SNOW FROM ALBANY SOUTHEASTWARD TO RAIN...POSSIBLY A BRIEF PERIOD
OF FREEZING RAIN. FURTHER WEST...FREEZING RAIN AND OR SLEET MIGHT
PERSIST FOR AWHILE IN THE HIGHER TERRAIN OF THE
CATSKILLS/ADIRONDACKS AND EVEN MOHAWK VALLEY. MEANWHILE TO OUR
EAST...STRONG EASTERLY WINDS SHOULD WARM THESE AREAS ENOUGH TO
PREVENT ANY SIGNIFICANT ICING.
THE 12Z GFS AND 12Z EUROPEAN ARE STILL ABOUT 12 HOURS APART WITH THE
TIMING OF THE MAX PRECIPITATION. THE EUROPEAN HAS THE HEAVIEST
RAINFALL OCCURRING SATURDAY NIGHT WHILE THE GFS HAS IT MORE LATE IN
THE DAY ON SATURDAY. FOR NOW...WILL CONTINUE TO COMPROMISE AND END
THE HEAVIEST RAINFALL AROUND 06Z SUNDAY.
THE 12Z MREF PLUMES INDICATE MOSTLY RAIN WITH ONLY ABOUT 0.35 INCHES
FOR THE AVERAGE RAINFALL...WITH A FEW MEMBERS INDICATING SOME
FREEZING RAIN AND SLEET. VERY FEW HAD ANY SIGNIFICANT SNOW.
THE 15Z SREF PLUMES INDICATE ALMOST ALL RAIN HERE AT ALBANY WITH A
SLIGHTLY HIGHER QPF...AROUND 0.50 INCHES. WE LEAN MORE WITH THIS
SOLUTION.
RAIN LOOKS TO ACCUMULATE BETWEEN 0.50 INCH AND AN INCH...WITH SOME
LOCALLY HIGHER AMOUNTS TO NEAR TWO INCHES ACROSS OUR CATSKILLS. MORE
ABOUT THE RAINFALL WILL BE FOUND IN HYDROLOGY SECTION.
RIGHT NOW...WE HAVE ONLY A FEW INCHES OF SNOW (AND SLEET)
ACCUMULATIONS ACROSS OUR HIGHER TERRAIN...ONLY UP TO A COUPLE INCHES
IN VALLEY LOCATIONS. UP TO A THIRD OF AN INCH OF ICE IS POSSIBLE
ACROSS OUR HIGHER TERRAIN TO THE WEST. ALL THESE VALUES POINT TO AN
ADVISORY EVENT (AS OPPOSED TO WINTER STORM) THEREFORE...NO WINTER
STORM HEADLINES WILL BE ISSUED AT THIS TIME.
THE OTHER CONCERN WITH THIS UPCOMING STORM WILL BE THE WIND...MAINLY
THE EASTERLY WIND AHEAD OF THE SYSTEM...THAT COULD REACH AT LEAST
ADVISORY CRITERIA...MAINLY ACROSS OUR ELEVATED TERRAIN TO THE EAST.
ALL THESE CONCERNS...INCLUDING THE WINDS...WILL BE ADDRESSED IN OUR
HAZARDOUS WEATHER OUTLOOK. (HWO).
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
.A WINTRY MIX OF PRECIPITATION EXPECTED THIS WEEKEND...
SFC HIGH PRESSURE CONTINUED TO RIDGE IN FROM SOUTH OF HUDSON BAY.
THIS HIGH HAS BEEN IN THIS VICINITY FOR THE PAST WEEK...AND WILL
CONTINUE TO RESIDE IN THIS AREA THROUGH EARLY FRIDAY. THE DIFFERENCE
IS NOW THIS ANTICYCLONE IS SHIPPING IN CANADIAN MARINE AIR (AS
OPPOSED TO CANADIAN CONTINENTAL AIR) OUR WAY. THIS HIGH PRESSURE
WILL SLOWLY RETREAT INTO THE CANADIAN MARITIMES ON FRIDAY NIGHT. AS
IT DOES SO...IT WILL ALLOW ENERGY FROM THE HUGE MID WEST STORM...TO
BEGIN TO MOVE INTO THE REGION. IT LOOKS AS IF IT WILL REMAIN DRY ALL
DAY ON CHRISTMAS DAY. ANY PARTIAL CLEARING WILL BE FOLLOWED BY
INCREASING HIGH CLOUDS BY LATE IN THE DAY.
WITH THIS MARINE AIR IN PLACE...HIGH TEMPERATURES ON FRIDAY LOOK TO
BE MAINLY IN THE 30S EVERYWHERE ACROSS THE REGION. THIS VALUES ARE
CLOSE TO SEASONABLE NORMALS...EXCEPT A LITTLE HIGHER ACROSS THE
MOUNTAINS.
THEN...AS A LARGE AREA OF VORTICITY FROM THE LARGE STORM AS WELL AS
ITS ASSOCIATED WARM FRONT APPROACH THE REGION FRIDAY NIGHT...THE
THREAT FOR PRECIPITATION WILL INCREASE. AT THE SAME TIME
HOWEVER...RIDGING ALOFT WILL SERVE TO INHIBIT MOISTURE FROM
OVERSPREADING THE REGION. THEREFORE...IT LOOKS AS IF THE TIMING OF
THE PRECIPITATION WILL BE SLOWED DOWN A BIT...PROBABLY NOT REACHING
OUR EASTERN AREAS OF OUR CWA UNTIL LATE FRIDAY NIGHT OR AROUND 12Z
SATURDAY.
A SECONDARY LOW PRESSURE WILL FORM ALONG THE TRIPLE POINT OF THE
OCCLUDED FRONT NEAR VIRGINIA WHILE THE PRIMARY STORM INITIALLY
REMAINS ACROSS THE GREAT LAKES REGION. THE SECONDARY STORM WILL
ESTABLISH A WARM CONVEYOR ON SATURDAY (OR SATURDAY DAY NIGHT) WITH
PWAT VALUES NEAR THREE QUARTER INCHES NOSING INTO OUR SOUTHERN
AREAS.
WITH PLENTY OF COLD AIR IN PLACE INITIALLY...THIS PRECIPITATION WILL
LIKELY START OUT AS A LITTLE SNOW OR SLEET. ANY WARMING LAYERS ABOVE
FREEZING WILL LIKELY BRIEFLY COOL BACK BELOW FREEZING DUE TO
EVAPORATIVE COOLING WITH ONSET OF PRECIPITATION. HOWEVER...AN
INCREASING LOW LEVEL JET OUT OF THE SOUTHEAST WILL BRING THE WARM
NOSE ACROSS MOST OF OUR REGION ON SATURDAY. THIS SHOULD CHANGE ANY
SLEET AND SNOW FROM ALBANY SOUTHEASTWARD TO RAIN...POSSIBLY A BRIEF
PERIOD OF FREEZING RAIN. FURTHER WEST...FREEZING RAIN AND OR SLEET
MIGHT PERSIST FOR AWHILE IN THE HIGHER TERRAIN OF THE
CATSKILLS/ADIRONDACKS AND EVEN MOHAWK VALLEY. MEANWHILE TO OUR
EAST...STRONG EASTERLY WINDS SHOULD WARM THESE AREAS ENOUGH TO
PREVENT ANY SIGNIFICANT ICING.
THE 12Z GFS AND 12Z EUROPEAN ARE STILL ABOUT 12 HOURS APART WITH THE
TIMING OF THE MAX PRECIPITATION. THE EUROPEAN HAS THE HEAVIEST
RAINFALL OCCURRING SATURDAY NIGHT WHILE THE GFS HAS IT MORE LATE IN
THE DAY ON SATURDAY. FOR NOW...WILL CONTINUE TO COMPROMISE AND END
THE HEAVIEST PRECIPITATION AROUND 06Z SUNDAY.
THE 12Z MREF PLUMES INDICATE MOSTLY RAIN WITH ONLY ABOUT 0.35 INCHES
FOR THE AVERAGE RAINFALL...WITH A FEW MEMBERS INDICATING SOME
FREEZING RAIN AND SLEET. VERY FEW HAD ANY SIGNIFICANT SNOW.
THE 15Z SREF PLUMES INDICATE ALMOST ALL RAIN (WITH A FEW FREEZING
RAIN MEMBERS NOT AMOUNTING TO MUCH QPF) AT ALBANY. THE QPF IS
SLIGHTLY HIGHER QPF...AROUND 0.50 INCHES. WE LEAN MORE WITH THIS
WARMER AND SOMEWHAT WETTER SOLUTION.
RAIN LOOKS TO ACCUMULATE BETWEEN 0.50 INCH AND AN INCH ACROSS
CWA...WITH SOME LOCALLY HIGHER AMOUNTS TO NEAR TWO INCHES ACROSS OUR
CATSKILLS. MORE ABOUT THE RAINFALL WILL BE FOUND IN HYDROLOGY
SECTION.
RIGHT NOW...WE HAVE ONLY A FEW INCHES OF SNOW (AND SLEET)
ACCUMULATIONS ACROSS OUR HIGHER TERRAIN...ONLY UP TO A COUPLE INCHES
IN VALLEY LOCATIONS. UP TO A THIRD OF AN INCH OF ICE IS POSSIBLE
ACROSS OUR HIGHER TERRAIN TO THE WEST. ALL THESE VALUES POINT TO A
POTENTIAL ADVISORY EVENT (AS OPPOSED TO WINTER STORM) THEREFORE...NO
WINTER STORM HEADLINES WILL BE ISSUED AT THIS TIME.
THE OTHER CONCERN WITH THIS UPCOMING STORM WILL BE THE WIND...MAINLY
THE EASTERLY WIND AHEAD OF THE SYSTEM...THAT COULD REACH AT LEAST
ADVISORY CRITERIA LATE SATURDAY INTO SATURDAY..MAINLY ACROSS OUR
ELEVATED TERRAIN TO THE EAST.
ALL THESE CONCERNS...INCLUDING THE WINDS...WILL BE ADDRESSED IN OUR
HAZARDOUS WEATHER OUTLOOK. (HWO).
MOSTLY POPULATED WITH THE MET NOS (WITH A FEW TWEAKS) WHICH CONTINUE
TO USUALLY DO MUCH BETTER THAN THE MAV GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ON SUNDAY NIGHT INTO MONDAY...THE SLOW MOVING UPPER LEVEL LOW /THE
SAME LOW RESPONSIBLE FOR THE WEEKEND PRIMARY SFC SYSTEM ACROSS THE
MIDWEST/ WILL FINALLY MOVE ACROSS THE REGION. WITH 850 HPA TEMPS
SUFFICIENTLY COLD...THIS MAY LEAD TO SOME LIGHT SNOW SHOWERS ACROSS
THE REGION...ALTHOUGH IT/S POSSIBLE SOME RAIN MAY MIX IN EXTREME
SOUTHERN AREAS ON MON AFTN AS THE BOUNDARY LAYER WARMS UP A BIT.
ONCE THE VORT MAX REACHES THE COAST...IT MAY GET A WEAK SFC LOW
GOING OFF LONG ISLAND BY MONDAY AFTN...BUT THIS SHOULD BE TOO LATE
TO BRING ANY ADDITIONAL APPRECIABLE QPF TO OUR AREA. WOULD NOT
EXPECT MUCH QPF TOTAL ACROSS THE CWA...GENERALLY A TENTH OF AN INCH
OR LESS. TEMPS WILL REMAIN CLOSE TO SEASONAL AVGS FOR BOTH SUN
NIGHT/MON.
AN ARCTIC FRONT WILL DROP ACROSS THE REGION MON NIGHT. THIS MAY
BRING A FEW ADDITIONAL SNOW SHOWERS...MAINLY TO NORTHERN AREAS AND
THE HIGHER TERRAIN. THE MAIN IMPACT OF THIS BOUNDARY WILL BE TO
USHER A MUCH COLDER AIR MASS INTO THE REGION FOR THE MID WEEK
PERIOD. WITH 850 HPA TEMPS DROPPING TO -18 TO -22 DEGREES C BY
TUESDAY MORNING...THIS WILL ALLOW FOR MAX TEMPS ONLY IN THE TEENS
AND 20S ON TUES WITH A GUSTY W-NW WIND AS WELL. ON TUESDAY
NIGHT...VERY COLD TEMPS ARE EXPECTED WITH SINGLE DIGITS AND BELOW
ZERO READINGS IN THE HIGHER TERRAIN. WILL HAVE TO WATCH ACROSS THE
ADKS FOR SOME POTENTIAL FOR SOME WIND CHILLS TO REACH NEAR ADVISORY
CRITERIA IN A FEW OF THE HIGHEST ELEVATIONS. TUE SHOULD REMAIN DRY
IN MOST AREAS...BUT EXTREME WESTERN PARTS OF THE AREA COULD SEE SOME
LIGHT LAKE EFFECT SNOW SHOWERS.
COLD BUT DRY WEATHER WILL CONTINUE FOR WED INTO THURSDAY MORNING.
WITH HIGH PRESSURE MOVING OVER THE REGION...INVERSION HEIGHTS WILL
LOWER AND ANY LAKE EFFECT WILL SHUT OFF. TEMPS WILL REMAIN BELOW
NORMAL FOR WED INTO THURS AS WELL. WILL HAVE TO WATCH FOR THE
DEVELOPMENT OF A SOUTHERN STREAM SYSTEM FOR LATE THURSDAY INTO
FRIDAY. SOME RECENT RUNS OF THE GFS...AS WELL AS THE 12 UTC ECMWF
HAS SHOWN THIS LOW TO MOVE UP THE EASTERN SEABOARD TO SPREAD SNOW
ACROSS THE REGION. WITH A FAVORABLE +PNA AND -NAO THROUGH THE END OF
THE MONTH...AS WELL AS THE MJO LIKELY IN PHASE 1...TELECONNECTIONS
WOULD FAVOR THIS SCENARIO...SO WILL CAREFUL WATCH THE MODELS OVER
THE NEXT SEVERAL DAYS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 2350Z...AT KGFL AND KALB...THE STRATUS DECK PERSISTS...AFTER A
FEW BREAKS DEVELOPED EARLIER. LATEST SFC OBS...AS WELL AS IR
SATELLITE OBS INDICATE THAT THIS LOW CLOUD LAYER HAS ACTUALLY BEEN
EXPANDING OVER THE LAST HOUR...WITH BASES LOWERING SLIGHTLY. BASED
ON NAM/RUC13 BUFKIT FORECAST PROFILES...THIS STRATUS LAYER SHOULD
PERSIST OVERNIGHT...AND LOWER INTO THE IFR RANGE...AND THUS HAVE
INDICATED THIS IN CURRENT TAFS. CONFIDENCE LEVELS STILL ARE SOMEWHAT
LOW...HOWEVER...GIVEN SOME BREAKS NEARBY. SHOULD MORE BREAKS
DEVELOP/EXPAND...THEN IFR VSBYS FROM GROUND FOG WOULD BE
POSSIBLE...ESP LATE...GIVEN FAIRLY MOIST CONDITIONS WITHIN THE
BOUNDARY LAYER ALONG WITH LIGHT TO CALM WINDS.
AT KPOU...SKIES ARE INITIALLY CLEAR. HOWEVER...SOME STRATUS MAY
DEVELOP HERE LATER TONIGHT...ALONG WITH MVFR/IFR VSBYS AS MOIST
BOUNDARY LAYER LINGERS. THUS...HAVE FORECAST MVFR/IFR
CONDITIONS...MAINLY FOR AFTER MIDNIGHT.
LOW CLOUDS...AND ASSOCIATED IFR/MVFR CONDITIONS MAY LINGER THROUGH
MUCH OF FRI MORNING...AND IN SOME AREAS...SUCH AS KGFL...COULD EVEN
LINGER INTO THE EARLY AFTERNOON GIVEN VERY LIGHT LOW LEVEL
WINDS...AND EXPECTED WEAK MIXING. THE BEST CHANCE FOR VFR CONDITIONS
WOULD BE LATE IN THE TAF PERIOD...ESP AT KPOU.
OUTLOOK...
FRI NGT...VFR DETERIORATING TO MVFR AS WINTRY MIX MOVES IN.
SAT-SAT NGT...MVFR-IFR...WITH A WINTRY MIX. A CHANGE OVER TO
RAIN...AT KPOU MID TO LATE MORNING...AT KALB BY EARLY AFTERNOON
AND AT KGFL EARLY IN THE EVENING.
SUN...VFR...MVFR POSSIBLE WITH CHC -SHRA/-SHSN.
MON...VFR...MVFR POSSIBLE WITH CHC -SHSN.
TUE...VFR...NO SIG WX.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS THROUGH FRIDAY. THEN...THE NEXT SYSTEM WILL BRING
A POTPOURRI MIX OF PRECIPITATION STARTING LATE FRIDAY NIGHT OR EARLY
SATURDAY. IT LOOKS LIKE RAIN WILL BE THE PRIMARY PRECIPITATION TYPE
FROM ALBANY SOUTHWARD. UP TO 1.5 INCHES IS POSSIBLE ACROSS OUR
DACKS/LITCHFIELD HILLS AND BERKS. THIS MIGHT BE ENOUGH TO PRODUCE
SOME EXCESSIVE RUNOFF FROM MELTING SNOW (WITH A WATER EQUIVALENT OF
GENERALLY AROUND AN INCH). SOME SIGNIFICANT RISES ARE POSSIBLE ON
THE HOUSATONIC BASIN AND MAYBE THE SCHOHARIE AND ESOPUS.
HOWEVER...AT THIS TIME...IT DOES NOT APPEARS THE LEVELS WILL QUITE
REACH FLOOD LEVELS. FURTHER NORTH...WITH MORE MIXED PRECIPITATION
AND COLDER TEMPERATURES ANY SNOWMELT SHOULD BE NEGLIGIBLE AND ANY
RUNOFF MINIMAL.
WE WILL CONTINUE TO MONITOR THE SITUATION AS THE EVENT NEARS.
AFTER THE SYSTEM WINDS DOWN ON SUNDAY...IT WILL BE MAINLY DRY INTO
EARLY NEXT WEEK. IT WILL TURN COLDER SO THAT ANY PRECIPITATION THAT
FALLS AFTER THAT...WOULD FALL AS MAINLY SNOW.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...HWJIV
NEAR TERM...HWJIV
SHORT TERM...HWJIV
LONG TERM...FRUGIS
AVIATION...KL/KGS
HYDROLOGY...RCK
