000 FXUS61 KALY 251119 AFDALY AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 620 AM EST WED NOV 25 2009 .SYNOPSIS... WEAK HIGH PRESSURE WILL DRIFT TO THE GULF OF MAINE TODAY WHILE A VERY WEAK DISTURBANCE BRINGS A FEW VERY LIGHT SHOWERS TO SOME SPOTS BY AFTERNOON. OUR REGION WILL BE BETWEEN TWO STORM SYSTEMS ON THANKSGIVING DAY WHICH WILL YIELD A DRY MILD DAY. AN STRONG UPPER LEVEL STORM SYSTEM WILL ACROSS THE REGION ON FRIDAY BRINGING UNSETTLED WEATHER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... RADARS INDICATING SOME SPRITZ MOVING UP ACROSS THE ADIRONDACKS...WITH PERHAPS AN HUNDREDTH OF AN INCH OR TWO. WHILE A STORM SYSTEM IN THE OHIO VALLEY WILL MISS US BY GOING NORTH...A PIECE OF VORTICITY HAS BROKEN AWAY FROM THE MAIN FEATURE (ALONG WITH A VERY WEAK SURFACE TROUGH). THIS VERY WEAK DISTURBANCE IS RESPONSIBLE FOR THE VERY LIGHT SHOWERS WHICH WITH TIME...WILL ATTEMPT TO PROPAGATE EASTWARD ACROSS THE REMAINDER OF THE REGION BY AFTERNOON. AT MOST...SCATTERED LIGHT SHOWERS MIGHT BRING A COUPLE OF HUNDREDTHS OF AN INCH IN A FEW SPOTS BUT THIS SYSTEM SHOULD HAVE NO IMPACT ON TRAVEL. KEEP IN MIND...THAT MANY SPOTS WILL NOT RECEIVE ANY SHOWER ACTIVITY. HOWEVER...PATCHY DENSE FOG COULD BE A PROBLEM FOR SOME EARLY IN THE MORNING BEFORE BURNING OFF. WITH THE DISTURBANCE THERE WILL BE LOTS OF CLOUDS TODAY...BUT A FEW BREAKS OF SUNSHINE ARE POSSIBLE. WITH MORE CLOUDS AND THE WIDELY SCATTERED SHOWERS...LOWERED TEMPS A COUPLE OF POINTS COMPARED TO WHAT WE HAD YESTERDAY. ACTUALLY WENT A DEGREE HIGHER THAN THE MET/MAV BLENDS WHICH FOR A CHANGE...WERE CLOSE TO EACH OTHER. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... THE REASON THE OHIO STORM WILL MAINLY MISS US (EXCEPT FOR THE VORTICITY PIECE) IS BECAUSE ANOTHER SYSTEM WAS DIVING SOUTH FROM MANITOBA CANADA. THIS SYSTEM IS FORCING THE FIRST ONE TO EJECT NORTHWARD INTO ONTARIO. THIS SECOND SYSTEM IS THE ONE THAT WILL LIKELY IMPACT OUR REGION ON FRIDAY. HOWEVER...BEFORE THEN...OUR AREA WILL BE SANDWICHED BETWEEN A DEVELOPING OCEAN STORM WELL TO OUR EAST...AND THE IMPENDING UPPER AIR LOW SYSTEM TO OUR WEST ON THANKSGIVING DAY. THE AFOREMENTIONED WEAK DISTURBANCE MIGHT STILL BRING A SHOWER OR TWO THIS EVENING BEFORE LIFTING TO OUR NORTHEAST OVERNIGHT. BEHIND IT...WITH NO REAL HIGH PRESSURE IN PLACE...CLOUDS COULD BE SLOW TO BREAK UP (IF AT ALL). WITH DRYING IN THE MID LEVELS BUT MOISTURE POSSIBLY INCREASING IN THE LOWER LEVELS...A LITTLE PATCHY DRIZZLE MIGHT ENSUE OVERNIGHT TONIGHT. THEN ON THANKSGIVING DAY...THE BIGGEST CHALLENGE WILL BE PREDICTING THE SKY COVER. OTHERWISE...IT SHOULD BE A DRY DAY. OUR THINKING IS THE DAY WILL START OFF CLOUDY (OR MOSTLY CLOUDY) WITH SOME MIDDAY BREAKS BEFORE CLOUDS REDEVELOP AGAIN LATE IN THE DAY. THROUGH IT ALL...WE WILL ENJOY ONE MORE MILD DAY AS H850 TEMPERATURES REMAIN IN THE 1C-3C WITH AN OPPORTUNITY FOR LITTLE MORE MIXING COMPARED TO PREVIOUS DAYS. EVEN WITH MORE CLOUDS THAN SUNSHINE...TEMPERATURES WILL GENERALLY TOP OUT IN THE 50-55 RANGE...EXCEPT 45-50 IN MOUNTAIN AREAS. THESE VALUES ARE A GOOD 5-7 DEGS ABOVE SEASONAL AVERAGES. IT LOOKS AS IF NO THANKSGIVING WEATHER RECORDS WILL BE THREATEN IN THE ALBANY (RAINFALL/SNOWFALL/TEMPERATURES ETC.). IT WILL BE CONSIDERABLY MILDER THAN LAST YEAR WHEN THE HIGH WAS ONLY 43 DEGREES IN ALBANY. BY THANKSGIVING NIGHT...THE NEW UPPER AIR LOW WILL BE APPROACHING WESTERN NEW YORK STATE. AT THE SAME TIME...THE DEVELOPING COASTAL STORM...A SPIN OFF FROM THE SOUTHERN SUBTROPICAL JET WILL BE TO OUR EAST. THE HUGE WEATHER PROBLEM IS WHETHER OR NOT ENERGY FROM THE OCEAN STORM WILL PHASE WITH THE ENERGY FROM THE NORTHERN BRANCH (UPPER AIR LOW). IF IT WERE...A SIGNIFICANT PRE WINTER STORM WOULD ENSUE. HOWEVER...THE SIGNALS ARE NOT CLEAR THAT A FULL PHASING WILL HAPPEN. THE GFS/EUROPEAN/CANADIAN MODELS SUGGEST THAT A FULL PHASING WILL NOT OCCUR...UNTIL BOTH SYSTEM ARE NORTH AND EAST OF OUR REGION. THAT IS NOT TO SAY WE WILL ESCAPE PRECIPITATION. THERE IS A LOT OF MOISTURE WITH THE SOUTHERN STORM NOTED ON THE WATER VAPOR LOOP. IT DOES APPEARS THAT SOME OF THIS MOISTURE WILL BE EJECTED INTO THE UPPER LEVEL SYSTEM...WITH OR WITHOUT THE SURFACE STORM. THE NAM CONTINUES TO MORE OF AN OUTLIER...SUGGESTING MOISTURE WILL BE VERY LIMIT WITH THE UPPER AIR LOW...AS THE SURFACE LOW IS EVEN A LITTLE FURTHER AWAY FROM THE UPPER AIR STORM. THEE IS STILL A BIT SPREAD OF THE SURFACE TRACK ON THE GFS ENSEMBLES. BOTTOM LINE...A LOT UNCERTAINTY STILL CONTINUES WITH THE EVOLUTION OF THIS UPCOMING STORM. THE FIRST OHIO VALLEY STORM...THE ONE THAT WILL GET EJECTED NORTHWARD...MIGHT HAVE ENOUGH PUSH TO DISPLACE THE BAROCLINIC ZONE FURTHER SOUTH AND EAST WHICH WOULD FORCE THE COASTAL STORM TO STAY FURTHER TO OUR EAST. THUS FAR...THIS BAROCLINIC ZONE IS NOT IMPRESSIVE...BUT WILL BECOME MORE SO BY THURSDAY NIGHT. FOR THE ABOVE REASONS...WILL CONTINUE WITH LIKELY POPS LATE THANKSGIVING NIGHT AND FRIDAY (AS OPPOSED TO CATEGORICAL). MOST MODELS ARE PICKING UP ON SOME ELEVATION DIFFERENCE IN QPF...WHICH SEEMS VERY REASONABLE GIVEN PAST CSTAR RESEARCH ON THE MATTER OF COLD CUTOFF LOWS. THE STUDIES HAVE INDICATE HIGHER TERRAIN COULD RECEIVE UP TO SEVERAL TIMES MORE PRECIPITATION THAN THE VALLEY AREAS. THE 00Z EUROPEAN DEVELOPS A DEFORMATION ZONE TO THE EAST OF THE HUDSON VALLEY WHILE THE 00Z GFS DEVELOPED IT TO THE WEST. EITHER WAY...IT WILL TAKE MORE TO DETERMINE WHERE ANY PRECIPITATION MAXIMA WOULD TAKE PLACE. PRECIPITATION IS LIKELY TO OVERSPREAD THE REGION LATE THURSDAY NIGHT INTO FRIDAY. INITIALLY THE AIR LOOKS WARM ENOUGH FOR ALL RAIN...EVEN IN THE MOUNTAINS. HOWEVER...WITH TIME...THE COLUMN WILL COOL ENOUGH FOR A CHANGEOVER TO SNOW ACROSS THE HIGHER TERRAIN. IT MIGHT TAKE MOST OF THE DAY FRIDAY FOR THIS TO HAPPEN. HOWEVER...IF PRECIPITATION AMOUNTS ARE HEAVIER THAN WHAT WE ARE CURRENTLY FORECASTING...COOLING FROM MELTING SNOWFLAKES COULD COOL THE COLUMN DOWN MUCH FASTER. RIGHT THOUGH...THE PROBABILITY OF A 24-HR ONE INCH PRECIPITATION AMOUNTS LOOKED SMALL ON THE 00Z MREFS AND EVEN SMALLER ON THE SREFS. OVERNIGHT LOW TEMPERATURES THANKSGIVING NIGHT LOOKS TO BE IN 30S BUT ABOVE FREEZING. THEN...THEY PROBABLY WILL NOT RISE MUCH ON FRIDAY...AND IN SOME CASES MIGHT ACTUALLY FALL...AS THE WIND TURNS NORTH TO NORTHWESTERLY AND THE H850 TEMPERATURE COOL BELOW 0C...WHILE H925 TEMPERATURES APPROACH ZERO IN THE MOUNTAINS. LEFT-OVER "WRAP AROUND" MAINLY UPSLOPE PRECIPITATION LOOKS TO LINGER INTO FRIDAY NIGHT. BY THIS TIME...TEMPERATURES WILL DROP AROUND THE FREEZING MARK IN VALLEY LOCATIONS....20S OVER THE MOUNTAINS. THERE IS A POTENTIAL FOR DUSTING OF SNOW EVEN IN VALLEY LOCATIONS...AND PERHAPS SEVERAL INCHES OVER THE HIGHER TERRAIN. THE OCEAN STORM SHOULD BE A FULL BLOWN NOR'EASTER BY FRIDAY NIGHT...SITTING OVER THE GULF OF MAINE. AS IT BEGINS TO PULL AWAY...A GUSTY NORTHWEST WIND WILL KICK IN. MORE ABOUT THAT WILL FOLLOW IN THE LONG TERM DISCUSSION. && .LONG TERM /SATURDAY THROUGH TUESDAY/... IN THE WAKE OF THE NOR-EASTER...COLD ADVECTION WILL PURSUE ON THE HEELS OF STRONG WESTERLY WINDS. MOMENTUM TRANSFER POTENTIAL SUGGESTS WE EFFECTIVELY TAP INTO THE MID-UPPER 40KT RANGE AS THIS WOULD QUALIFY FOR WIND HEADLINES ON SATURDAY. WE WILL CONTINUE TO HIGHLIGHT IN THE HWO THIS MORNING. FURTHERMORE...WITH THE COLDER AND MOIST CYCLONIC FLOW AND CONTRIBUTIONS FROM LAKE ONTARIO...RAIN/SNOW SHOWERS ARE EXPECTED. WITH FAVORABLE UPSLOPE AREAS SUCH AS THE DACKS...SOUTHERN GREENS AND PORTIONS OF THE CATSKILLS...POTENTIAL FOR ACCUMULATING SNOW AS THE BOUNDARY LAYER CONTINUES TO COOL OFF THROUGH THE DAY. SATURDAY NIGHT...WEATHER IMPROVES QUICKLY AS SURFACE PRESSURE GRADIENT RELAXES AND DECOUPLING OCCURS AS SURFACE TEMPS ARE EXPECTED TO COOL OFF RATHER QUICKLY DURING THE EVENING. SUBSIDENCE WILL ALSO INCREASE WHICH WILL AID IN THE REDUCTION OF CLOUD COVER FOR A CHILLY NIGHT. DEPENDING ON WHERE SNOW COVER SETS UP WILL DICTATE THE OVERNIGHT LOWS. FOR NOW...WE WILL GENERALLY FAVORS THE 20S FOR THE MAJORITY OF THE CWA. FOR THE SECOND HALF OF THE WEEKEND...UPSTREAM THE NEXT TROUGH EVOLVES AS STRONG PACIFIC SYSTEM COMES ASHORE. THE UPPER PATTERN FAVORS A MORE ELONGATED LONG WAVE TROUGH THIS TIME AROUND WHICH WILL ALLOW FOR MORE POSITIVE RESPONSE FROM THE GULF OF MEXICO. SUNDAY SHOULD REMAIN DRY AND SEASONABLE AS THIS UPSTREAM FEATURE/S/ UNFOLD. FOR EARLY NEXT WEEK...MODELS WILL NATURALLY HAVE DIFFICULTY WITH RESOLVING WAVES AND STRENGTH OF THESE SYSTEMS. CONSENSUS FAVORS AN INCREASE IN CLOUD COVER AND PRECIPITATION AS GULF MOISTURE TRANSPORT INCREASES OVER THE EASTERN US. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... VARIETY OF FLIGHT CATEGORIES THIS MORNING ACROSS THE TAF SITES WITH A SOLID STRATUS DECK SOUTH OF THE CAPITAL REGION /MVFR CIG/ AND POCKETS OF IFR FROM THE CAPITAL REGION AND POINTS NORTH DUE TO FOG. WITH AN INFLUX OF MOISTURE CONTINUING THROUGH THE DAY...TAF SITES ARE EXPECTED TO BECOME MORE UNIFORM WITH MVFR CIGS WITH A LIGHT SOUTH-SOUTHEAST WIND. THERE COULD BE SOME LIGHT RAIN SHOWERS...AS SEEN ON THE RADAR THIS MORNING OVER CENTRAL NY AND THE DACKS...APPROACHING THIS AFTERNOON FOR THE HUDSON RIVER VALLEY AND WILL PLACE VCSH AT THIS TIME. LOW LEVEL MOISTURE IS EXPECTED TO QUICKLY INCREASE TOWARD THIS EVENING WITH THE CHANCE FOR EITHER LIGHT RAIN/DRIZZLE. THIS TOO WILL LOWER THE CIGS DOWN TO AT LEAST IFR...PERHAPS LOWER...AND WE WILL CONTINUE TO MONITOR TRENDS. OUTLOOK... THANKSGIVING DAY...VFR TO MVFR...CIG...NO SIG WX AT THIS TIME. THU NGT-FRI...MVFR/IFR...-SHRA/PDS -RA. CHC LLWS. FRI NGT-SAT...MVFR/IFR...-SHRA CHG TO -SHSNRA. POSS LLWS. WINDY. SUN...VFR. NO SIG WX. && .HYDROLOGY... NO HYDRO PROBLEMS THROUGH THANKSGIVING DAY. THE NEXT CHANCE OF WIDESPREAD PRECIPITATION WILL BE FROM LATE THURSDAY NIGHT INTO THE EARLY PART OF THE WEEKEND...AS A POTENTIALLY STRONG STORM MAY IMPACT THE REGION. HOWEVER...AT THIS POINT... ENOUGH RAINFALL TO SIGNIFICANTLY IMPACT AREA STREAMS AND RIVERS DOES NOT APPEAR LIKELY AS RIVER BASIN AVERAGE ARE FORECASTED TO REMAIN BELOW AN INCH REGION WIDE. 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...BGM AVIATION...BGM HYDROLOGY...HWJIV/GJM WWW.WEATHER.GOV/ALBANY