FXUS61 KALY 100237
AFDALY
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
937 PM EST WED DEC 9 2009
.SYNOPSIS...
AN AREA OF DEEP LOW PRESSURE OVER THE EASTERN GREAT LAKES
WEDNESDAY EVENING WILL MOVE NORTHEAST ACROSS EASTERN CANADA
THROUGH THURSDAY. WHILE ANOTHER AREA OF DEEP LOW PRESSURE ALONG
THE NEW ENGLAND COAST MOVES TOWARD THE CANADIAN MARITIMES. STRONG
AND GUSTY WESTERLY WINDS WILL DEVELOP ACROSS THE REGION OVERNIGHT
AND CONTINUE INTO SATURDAY USHERING IN A COLD AIRMASS. AS THE
COLDER AIR MOVES ACROSS THE RELATIVELY WARMER WATER OF LAKE
ONTARIO...LAKE EFFECT SNOW WILL DEVELOP OVERNIGHT AND CONTINUE
INTO EARLY SATURDAY IMPACTING THE WESTERN ADIRONDACKS. SIGNIFICANT
SNOWFALL IS EXPECTED.
&&
.NEAR TERM /THROUGH THURSDAY/...
SIGNIFICANT LAKE EFFECT EVENT SETTING UP...LAKE EFFECT SNOW
WARNING IN EFFECT FOR NORTHERN HERKIMER AND HAMILTON COUNTIES
WITH 1 TO 3 FEET OF SNOW EXPECTED TO ACCUMULATE FROM THURSDAY INTO
EARLY SATURDAY.
AN AREA OF DEEP LOW PRESSURE OVER THE EASTERN GREAT LAKES WILL
HEAD NORTHEAST INTO EASTERN CANADA OVERNIGHT...WHILE ANOTHER AREA
OF DEEP LOW PRESSURE ALONG THE NEW ENGLAND COAST HEADS TOWARD THE
CANADIAN MARITIMES. PRESSURE RISES SPREADING INTO WESTERN PORTION
OF THE FORECAST AREA AS OCCLUDED BOUNDARY PUSHES EASTWARD. WINDS
SHIFTED AT SYRACUSE BECOMING WESTERLY AROUND 23Z/WEDNESDAY. ADJUST
TEMPERATURES AS PREVIOUS FORECAST HAD THEM DROPPING TO MUCH TO
EARLY. COLDER AIRMASS WILL BE USHERED IN WESTERLY WINDS ON
BACKSIDE OF STORMS AS HIGH UNCUT THE LOWS BUILDING INTO
SOUTHEASTERN UNITED STATES CREATING A LONG WESTERLY FETCH.
NO CHANGES BEYOND TONIGHT PERIOD. HAVE STRONG AND GUSTY WESTERLY
WINDS HIGHLIGHTED IN HAZARDOUS WEATHER OUTLOOK THURSDAY FOR THE
POSSIBLE NEED FOR A WIND ADVISORY...WITH GUSTS UP TO AROUND 45 MPH.
WILL ALLOW MIDNIGHT SHIFT TO EXAMINE ALL THE NEW MODEL DATA...QUICK
LOOK AT THE NAM DOES NOT SUPPORT ISSUING A WIND ADVISORY AT THIS
TIME.
REFER TO PUBLIC INFORMATION STATEMENT FOR SNOWFALL REPORTS.
PREVIOUS DISCUSSION ISSUED AT 640 PM...SCATTERED SHOWERS ARE
MOVING ACROSS THE REGION...AHEAD OF THE SECOND COLD FRONT.
MEANWHILE TO OUR SOUTH...SCATTERED THUNDERSTORMS MOVED ACROSS THE
MID HUDSON VALLEY AND LITCHFIELD COUNTY. WE EVEN HAD A REPORT OF
SMALL HAIL IN LITCHFIELD COUNTY!
HAVE UPDATED THE ZONES TO DROP THE WIND ADVISORY FOR OUR
NORTHEASTERN ELEVATED AREAS. THE STRONG LOW LEVEL WIND JET HAS
SHIFTED NORTHEAST OF THIS REGION. WIND GUSTS HAVE QUITE COME DOWN
QUITE A BIT IN THE PAST FEW HOURS. ALSO UPDATED THE HOURLY GRIDS.
TEMPERATURES IN SOME CASES HAVE GONE UP A DEGREE OR TWO...AND MIGHT
INCREASE A FEW MORE BEFORE THE COLD FRONT...STILL LOCATED IN CENTRAL
NEW YORK...MOVES IN.
IMPRESSIVE PRESSURE RISES (AND WINDS) OUT NEAR BUFFALO. THE BEST
PRESSURE RISES LOOK TO LIFT NORTHEAST INTO CANADA SO THAT IS WHERE
THE STRONGEST WIND GUSTS WILL LIFT TO AS WELL. THE 18Z NAM INDICATES
NO PENNANTS IN THE 30 AGL OR 925 MB LEVEL ANYWHERE OVER OUR REGION
SO WE FEEL MORE CONFIDENT ABOUT NOT ISSUING ANOTHER WIND ADVISORY.
NO CHANGES TO OVERNIGHT LOWS OR ANYTHING LATER IN PERIOD.
PREVIOUS DISCUSSION ISSUED AT 520...DOUBLE BARRELED LOW PRESSURE...ONE
OVER MICHIGAN AND THE OTHER NEAR CAPE COD...CONTINUES TO SLOWLY
LIFT NORTHWARD.
UPSTREAM...IT LOOKS MORE LIKE SUMMER IN THAT THERE IS ACTUALLY
CONVECTION WITH CLOUD TO GROUND LIGHTNING STRIKES ASSOCIATED WITH A
COLD FRONT AND MUCH COLDER AIR ALOFT ACROSS WESTERN PA AND EVEN INTO
SW NY! SOME OF THE THUNDERSTORMS HAVE BEEN LOCALLY SEVERE.
THE GOOD NEWS IS THAT THE NUMBER OF LIGHTNING STRIKES HAS
DIMINISHED AS IT MOVES FURTHER INTO WESTERN PA AND WESTERN NY.
HOWEVER...THERE WERE ALSO A FEW STRIKES IN NW JERSEY.
WE DON'T BELIEVE THIS INSTABILITY WILL IMPACT MOST OF OUR COUNTY
WARNING AREA AS THE INSTABILITY WEAKENS. HOWEVER...WE WILL HAVE
TO CLOSELY MO NITER THIS SITUATION. THE ONLY EXCEPTION MIGHT BE OUR
LOWER CATSKILLS/MID HUDSON VALLEY/LITCHFIELD COUNTY WERE THE
OCCLUDED FRONT WILL MOVE THROUGH. FOR NOW...WILL COVER THIS THREAT
WITH A NOWCAST/SPS SINCE ANY CONVECTION ASSOCIATED WITH THE
CONVECTION OVER NW JERSEY WILL DONE BY 600 PM.
THIS WAS QUITE A SNOW EVENT...ESPECIALLY CONSIDERING MOST OF THE
SNOW FELL IN A SIX HOUR WINDOW INCLUDING THE MORNING DRIVE. PLEASE
REFER TO OUR PUBLIC STATEMENTS (PNS) FOR ALL THE LATEST SNOWFALL
TOTALS.
THE OTHER CONCERN IN THE NEAR TERM IS THE WIND ADVISORY...STILL
OUT FOR OUR ELEVATED TERRAIN TO OUR EAST. WIND GUSTS OVER 40 MPH
WERE STILL COMMON IN THIS AREA AND WILL BE FOR THE NEXT FEW HOURS.
WE EXTENDED THE WIND ADVISORY UNTIL 700 PM. AFTER THAT...THE
STRONG LOW LEVEL JET WILL BEGIN TO LIFT OFFSHORE AS THE SECONDARY
LOW...CURRENTLY NEAR CAPE COD...SHIFTS OFFSHORE.
ONE LAST THING. TEMPERATURES THIS EVENING MIGHT ACTUALLY RISE A
LITTLE BEFORE FALLING AHEAD OF THE SECOND COLD...WITH SOME SPOTS
TAKING A SHOT AT 40 DEGREES.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
THE LINE OF SHOWERS TO OUR SOUTH WITH OCCLUDED FRONT WILL HAVE LIFTED
OUT OF THE AREA...WHILE THE WEAKENING LINE OF SHOWERS ASSOCIATED
WITH THE SECONDARY COLD FRONT...WILL STILL BE MOVING ACROSS THE
REGION. PRECIPITATION TYPES WILL BE MIXED WITH MAINLY RAIN...BUT
COULD BE MIXED WITH SLEET...FREEZING RAIN AND EVEN SOME WET SNOW
FLAKES...ESPECIALLY NORTH OF ALBANY. LITTLE OR NO ACCUMULATION IS
EXPECTED WITH THESE SHOWERS ANYWHERE.
COLDER AIR WILL FILTER BEHIND THIS SYSTEM. THE WIND
FLOW WILL BE WSW AND THE FLOW DID NOT LOOK QUITE STRONG FOR US TO
ISSUE A WIND ADVISORY. HOWEVER...THERE WILL BE WIND GUSTS...FROM THE
WEST OR SOUTHWEST AT LEAST TO 30 MPH...POSSIBLY UP TO 40 MPH...BUT
STILL FALLING SHORT OF WIND ADVISORY CRITERIA.
A STRONG FETCH OF WESTERLY COLDER WIND WILL SET UP AS THE 975 MB LOW
LIFTS SLOWLY INTO EASTERN CANADA ON THURSDAY...AND BEGIN POTENTIALLY
IMPRESSIVE LAKE EFFECT SNOW EVENT OFF OF LAKE ONTARIO. WATER
TEMPERATES THERE ARE STILL IN THE UPPER 40S...MUCH WARMER THAN THE
H850 TEMPERATURE WHICH WILL DROP TO ABOUT -15C BY FRIDAY AND 700 MB
TEMPS TO ABOUT -25C! CROSS SECTIONS INDICATE IMPRESSIVE DENDRITIC
GROWTH OF SNOW CRYSTALS AS THE STRONGEST UPWARD MOTION INTERSECTS
THE -12 TO -18C TEMPERATURE RANGE. LOW LEVEL CAPES OFF THE BUFKIT
EXCEED 500 J/KG...ABOUT AS HIGH AS THEY GET.
THE LATEST NAM RUNS INDICATE THAT A BAND OF HEAVY SNOW WILL SET UP
INITIALLY JUST TO THE NORTH OF HERKIMER COUNTY...THEN SLOWLY SINK
INTO THE AREA NORTH OF ROUTE 28 IN BOTH HERKIMER AND HAMILTON
COUNTIES. A SERIES OF SHORT WAVES WILL SERVE TO FOCUS BURST OF
EXTREMELY HEAVY SNOWFALL...PERHAPS EXCEEDING RATES OF 4 INCHES AN
HOUR AT TIMES...OFF LAKE ONTARIO INTO AT LEAST HERKIMER
COUNTY...NEAR OR JUST NORTH OF OLD FORGE. KITHING COULD ACCOMPANY
THE HEAVY SNOW BURSTS. A GUSTY WEST WIND OF UP 35 MPH WILL PRODUCE
LOCALIZED WHITEOUTS AND PRODUCE VERY DANGEROUS TRAVELING CONDITIONS.
ONE TO LOCALLY THREE FEET OF SNOW COULD FALL OVER THIS AREA BY
SATURDAY MORNING. WE DECIDED TO GO AHEAD AND ISSUE A LAKE EFFECT SNOW
WARNING FOR THIS AREA FROM THURSDAY UNTIL EARLY SUNDAY MORNING.
AFTER PRECIPITATION FROM THE COLD AND OCCLUDED FRONT MOVE ON BY
LATER TONIGHT...THE VAST MAJORITY OF OUR REGION WILL BE MAINLY
DRY. THERE WILL BE LIGHTER SCATTERED SNOW SHOWERS AROUND THE AREA
SOUTH OF THE ADIRONDACK PARK...WITH LITTLE OR NO ACCUMULATION
EXPECTED. THE FLOW LOOKS TOO WEST TO SOUTHWESTERLY (AS OPPOSED TO
NORTHWEST) TO PRODUCE SIGNIFICANT UPSLOPE ACROSS THE SOUTHERN GREENS.
LATER...AS THE FLOW TURNS MORE NORTHWESTERLY BY SATURDAY
MORNING...THERE MIGHT BE A BETTER CHANCE OF UPSLOPE SNOW ACROSS THE
GREENS. HOWEVER...BY THAT POINT...MOISTURE CONTENT LOOKS QUITE LOW
AS THE FLOW REMAINS MORE ANTICYCLONIC THERE.
TEMPERATURES WILL BE GOING BELOW AVERAGE. OVERNIGHT LOWS WILL BE
25-30 TONIGHT...RISING ONLY INTO THE 30S TOMORROW (25-30 HIGHER
TERRAIN). TEMPERATURES WILL DROP INTO THE TEENS THURSDAY
NIGHT...AND RISE ONLY INTO THE 20S (TO NEAR 30 NEAR POUGHKEEPSIE)
ON FRIDAY.
WENT WITH A MAV/MET BLEND TONIGHT THROUGH TOMORROW NIGHT.
HOWEVER...BY FRIDAY...WENT WITH THE COLDER MET NOS...EXCEPT A LITTLE
HIGHER TO THE LEE OF THE CATSKILLS...TRENDING CLOSER TO THE BLEND.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
WE STILL MIGHT DEALING WITH SOME RESIDUAL LAKE EFFECT EVEN INTO
SATURDAY BEFORE THE GRADIENT BETWEEN HIGH PRESSURE TO THE
SOUTHWEST AND LOW PRESSURE UP IN CANADA...RELAXES. HIGH PRESSURE
WILL BUILD OVER THE REGION BY LATE SATURDAY. AFTER THAT...THE
MODELS...AT LEAST THE OPERATIONAL GFS DIVERGES FROM THE REMAINDER
OF THE SOLUTIONS.
THE 12Z OPERATIONAL GFS STILL INDICATES A STORM MOVING THROUGH THE
SOUTHERN BRANCH...OFF THE MID ATLANTIC...WILL PRODUCE SOME
SNOW....ESPECIALLY SOUTH OF ALBANY. NOT SO MUCH FROM THE ACTUAL
STORM...BUT AN INVERTED TROUGH ALONG WITH A NORTHEASTERLY FETCH
PRODUCING MOISTURE OFF THE OCEAN. THE STORM NEVER PHASES WITH
ENERGY FROM THE NORTHERN BRANCH...UNTIL BOTH ARE SAFELY OFF THE
COAST. WE HAVE SEEN THIS SETUP QUITE A BIT IN A FEW EVENTS THE
PAST MONTH...AND STILL ENDED UP WITH QPF MUCH HIGHER THAN ANY
OTHER MODEL INDICATED.
FOR NOW...SINCE THIS IS THE ONLY MODEL INDICATING THIS
SCENARIO...WITH THE EUROPEAN/CANADIAN GEM AND EVEN THE ENSEMBLES
FURTHER SOUTH (OR NON-EXISTENT) WITH THIS SOUTHERN STORM...WE WILL
CONTINUE TO INDICATE ONLY SLIGHT CHANCES IN THE GRIDS FOR
SATURDAY. HOWEVER...THIS SITUATION NEEDS TO BE CLOSELY MONITORED
SINCE THIS SCENARIO HAS HAPPENED WITH RECENT SYSTEMS.
OTHERWISE...IT WILL BE CONTINUE TO BE SEASONABLY COLD THROUGH THIS
PERIOD. STORM OR NOT...HIGH PRESSURE RETREATING OFFSHORE WILL
PRODUCE A SOUTHERLY FLOW OF ONLY SLIGHTER MILDER AIR BY EARLY
NEXT WEEK. A SERIES OF CLIPPERS MIGHT IMPACT THE AREA WITH LIGHT
PRECIPITATION. THE LAST OF THE SERIES MIGHT DELIVER A REALLY COLD
BLAST JUST BEYOND THE FORECAST PERIOD. FOR NOW...WENT WITH
SLIGHT/LOW CHANCES OF MAINLY SNOW SHOWERS AS TEMPERATURES RISE TO
NO BETTER THAN NORMAL AVERAGES...GENERALLY 30S BY DAY...20S AT
NIGHT.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
DEEP LOW PRESSURE MOVING ACROSS EASTERN GREAT LAKES WITH SECONDARY
LOW ALONG THE NEW ENGLAND COAST. AS THE LOWS MOVE NORTH OCCLUDED
BOUNDARY WILL MOVE ACROSS AREA. WITH THE FRONTAL PASSAGE WINDS
WILL SHIFT TO THE SOUTHWEST-WEST AND INCREASE IN SPEED AND BECOME
GUSTY AND REMAIN STRONG THROUGH THROUGH THE TAF PERIOD...00Z/FRIDAY.
LOW LEVEL WINDS...AROUND 2000 FEET...HAVE SHIFTED TO THE SOUTHWEST
AND REMAIN STRONG AT 35 TO 45 KNOTS. THE WINDS AT SURFACE ARE
LIGHT SO HAVE LOW LEVEL WIND SHEAR IN TAFS UNTIL SURFACE WINDS
SHIFT AND PICK UP IN SPEED.
HAVE RAIN SHOWERS MOVING ACROSS AREA IN ADVANCE OF THE OCCLUDED
BOUNDARY. WITH THE PASSAGE OF THE BOUNDARY WINDS WILL BECOME
WESTERLY AND COLDER AIR WILL BE USHERED IN CHANGING PRECIPITATION
TYPE TO SNOW.
OUTLOOK...
THU-FRI...WINDY. VFR-MVFR FOR MAINLY CIGS WITH CHC -SHSN AND LAKE
EFFECT SNOW DOWNWIND FROM LAKE ONTARIO.
SAT...VFR...NO SIG WX.
SUN-MON...MAINLY VFR WITH A SLIGHT CHC -SHSN.
&&
.HYDROLOGY...
THE SNOW DOWN SOUTH ALONG WITH LESS RAIN THAN FORECAST...PRODUCED
NO HYDRO PROBLEMS. EXCEPT FOR THIS EVENING...WE WILL STAY COLD
ENOUGH FOR LITTLE OR NO SNOW MELT. RAIN SHOWERS THIS EVENING COULD
PRODUCE SOME MINOR RISES DOWN SOUTH OF ALBANY BUT WELL UNDER
BANKFULL. OTHERWISE...NO HYDRO PROBLEM ARE FORESEEN FOR THE NEXT
WEEK.
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.
&&
.CLIMATE...
WE BROKE OUR DAILY SNOW FALL RECORD HERE IN ALBANY WITH 7.3 INCHES.
THE OLD RECORD WAS 6.3 INCHES SET BACK IN 1995 FOR THIS
DATE...DECEMBER 9TH.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR NYZ054-061.
LAKE EFFECT SNOW WARNING FROM 7 AM THURSDAY TO 7 AM EST
SATURDAY FOR NYZ032-033.
MA...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR MAZ001-025.
VT...WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR VTZ013-014.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW WARNING FROM 7 AM THURSDAY TO 7 AM EST
SATURDAY FOR NYZ032-033.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...IAA/HWJIV
NEAR TERM...IAA/HWJIV/WASULA
SHORT TERM...HWJIV
LONG TERM...HWJIV
AVIATION...IAA
HYDROLOGY...HWJIV/RCK
CLIMATE...HWJIV
