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[Printable]
861
FXUS61 KBUF 231012
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
512 AM EST SUN NOV 23 2014

.SYNOPSIS...
LOOK FOR WARMING TEMPERATURES AND SCATTERED SHOWERS TODAY AS WARMER
AIR SURGES NORTH ACROSS THE REGION AHEAD OF A RAPIDLY INTENSIFYING
LOW PRESSURE SYSTEM OVER THE CENTRAL MISSISSIPPI VALLEY.
TEMPERATURES WILL WARM FURTHER TONIGHT WITH MORE RAIN AS A WARM
FRONT LIFTS NORTH OUT OF THE OHIO VALLEY. THE WARMING TEMPERATURES
AND RAINFALL COMBINED WITH INCREASINGLY STRONG WINDS TONIGHT AND
ESPECIALLY MONDAY THROUGH MONDAY NIGHT WILL ACCELERATE MELTING OF
RECENT HEAVY SNOWS...CREATING A SIGNIFICANT FLOODING RISK ACROSS
PORTIONS OF WESTERN NEW YORK. A STRONG COLD FRONT WILL CROSS THE
REGION MONDAY EVENING...BRINGING A RETURN OF MORE WINTER-LIKE
TEMPERATURES AND A CHANCE OF SNOW BY LATER IN THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
THE FIRST ROUND OF SHOWERS THAT CROSSED THE REGION DURING THE
OVERNIGHT HOURS HAS EXITED WESTERN NY AND IS IN THE PROCESS OF
LEAVING THE NORTH COUNTRY AT THIS TIME...HOWEVER ANOTHER ROUND OF
SHOWERS LIFTING OUT OF NORTHERN OHIO IS EXPECTED TO IMPACT WESTERN
NY THIS MORNING AS ANOTHER SUBTLE UPPER LEVEL WAVE MAKES ITS WAY
ACROSS THE REGION ALONG WITH INCREASING WARM ADVECTION IN ADVANCE OF
A RAPIDLY DEEPENING LOW PRESSURE SYSTEM OVER THE CENTRAL MISSISSIPPI
VALLEY. THIS ROUND OF RAINFALL IS ONLY EXPECTED TO BRING A TENTH OF
AN INCH OR LESS AS IT CROSS THE REGION THIS MORNING. THE BIGGER
STORY WILL BE THE CONTINUED ABOVE-FREEZING TEMPERATURES THAT WILL
EXACERBATE MELTING OF THE RECENT HEAVY SNOWFALL ACROSS PORTIONS OF
WESTERN NEW YORK AND THE NORTH COUNTRY. THIS WARM ADVECTION WILL
PUSH TEMPERATURES INTO THE UPPER 40S ACROSS WESTERN NEW YORK AND THE
LOWER 50S NORTH OF THE FINGER LAKES...THOUGH HAVE KNOCKED THE TEMP
FORECAST BACK A COUPLE OF DEGREES DUE TO PERSISTENT CLOUD COVER THAT
WILL DOG THE REGION THROUGHOUT THE DAY.

THE WARMING TREND WILL CONTINUE THROUGH TONIGHT AS INCREASINGLY WARM
AIR SURGES NORTH ACROSS THE REGION WITH A STRONG WARM FRONT LIFTING
NORTHWARDS ON THE NOSE OF A 65KT LOW LEVEL JET. A STRONG TEMPERATURE
INVERSION ASSOCIATED WITH THIS WARM ADVECTION SHOULD SHIELD MUCH OF
THE FORECAST AREA FROM THE STRONG WINDS ALOFT...HOWEVER WITH THE
LOWER LEVELS OF THE ATMOSPHERE SHOWING SOUTH-SOUTHEASTERLY
ORIENTATION TO THE FLOW AND THE INVERSION SETTING UP NEAR THE
CHAUTAUQUA RIDGE-TOP...CONDITIONS ARE FAVORABLE FOR STRONG
DOWNSLOPING WINDS ALONG THE LAKE ERIE SHORELINE...WHERE A WIND
ADVISORY HAS BEEN POSTED FOR TONIGHT. OTHERWISE...THE OTHER FEATURE
ASSOCIATED WITH THE WARM FRONTAL PASSAGE WILL BE THE DEVELOPMENT OF
WIDESPREAD RAINFALL ACROSS THE REGION AS DEEP ISENTROPIC UPLIFT AND
MOISTURE TRANSPORT ON THE NOSE OF THE AFOREMENTIONED JET MOVES ACROSS
THE LOWER GREAT LAKES. DOWNSLOPING SHOULD DIMINISH RAINFALL AMOUNTS
ACROSS FAR WESTERN NEW YORK...KEEPING THOSE AMOUNTS TO AROUND A
QUARTER OF AN INCH ACROSS THE HEAVIEST-HIT SNOWFALL AREAS TONIGHT
WITH HIGHER AMOUNTS APPROACHING A QUARTER TO A HALF-INCH ACROSS THE
NIAGARA PENINSULA AND NEAR THE PA BORDER IN THE SOUTHERN TIER AND ON
THE TUG. NONETHELESS...THE SHEER VOLUME OF WATER FROM THE SNOWMELT
ACROSS PORTIONS OF WESTERN NEW YORK WILL CREATE A PERSISTENT FLOOD
THREAT...PARTICULARLY ALONG THE BUFFALO CREEKS AND AREAS WITH POOR
DRAINAGE...ESPECIALLY AS WE MOVE FROM TONIGHT INTO MONDAY.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
THE MAIN CONCERNS FOR MONDAY INTO TUESDAY REMAIN: 1) THE WARM UP
WITH SOME RAIN AND THE POTENTIAL FLOODING AND 2) A POSSIBLE HIGH
WIND EVENT ON MONDAY...FOR WHICH A HIGH WIND WATCH HAS BEEN ISSUED
FOR PORTIONS OF WESTERN NEW YORK.

PHASING BETWEEN THE SUBTROPICAL AND POLAR JETS OVER THE MIDWEST WILL
ALLOW FOR AN AMPLIFIED UPPER-LEVEL PATTERN...WITH DEEP SOUTHWESTERLY
WINDS OVER THE FORECAST AREA ON MONDAY. A RAPIDLY DEEPENING SURFACE
LOW WILL TRACK FROM THE MIDWEST ACROSS THE UPPER GREAT LAKES AND
INTO CANADA. THIS WILL ADVECT ABNORMALLY WARM TEMPERATURES ACROSS
NEW YORK STATE AS A WARM FRONT LIFTS ACROSS THE STATE SUNDAY NIGHT.
PRECIPITATION WILL PUSH FROM SOUTH TO NORTH ACROSS THE AREA WITH
THIS WARM FRONT PASSAGE. FORECAST MODELS ARE IN GOOD AGREEMENT WITH A
VERY STRONG LOW-LEVEL JET PUSHING ACROSS NEW YORK STATE...WITH A
CONSENSUS OF 70+ KNOTS AT 850 MB. THE SOUTHEASTERLY COMPONENT TO
THIS INITIAL LOW-LEVEL JET WILL BRING A STRONG WIND THREAT ALONG THE
LAKE ERIE SHORELINE...INCLUDING DUNKIRK...DUE TO DOWNSLOPE WINDS OFF
THE CHAUTAUQUA RIDGE. THE OTHER IMPACT OF THESE SOUTHERLY DOWNSLOPE
WINDS WILL BE TO EAT AWAY AT SOME OF THE PRECIPITATION ALONG THE WARM
FRONT...WHICH COULD HELP TO LIMIT QPF AMOUNTS SOMEWHAT. HOWEVER THE
WARM FRONT AND QG FORCING WILL LIKELY OVERWHELM THE DOWNSLOPE...SO
QPF AMOUNTS AROUND 0.25 OR SLIGHTLY MORE STILL SEEM REASONABLE.
ANOTHER IMPACT OF THE WARM AIR ADVECTION AND INCREASING WINDS WILL
BE TO KEEP TEMPERATURES FROM FALLING MUCH AT ALL SUNDAY NIGHT INTO
MONDAY MORNING...WHICH WILL HELP EXPEDITE THE SNOW MELT PROCESS.

DURING THE DAY MONDAY THE WINDS ALOFT VEER TO THE SOUTHWEST WITH A
MORE FAVORABLE ORIENTATION FOR A WIDESPREAD STRONG WIND EVENT AS
WINDS ALOFT ARE MIXED TO THE SURFACE. IN COMPARING THE FORECAST
PATTERN TO LOCAL RESEARCH ON HIGH WIND EVENTS ACROSS WESTERN NEW YORK
THIS EVENT MATCHES VERY WELL TO THE AVERAGE PATTERN SEEN DURING HIGH
WIND EVENTS. TEMPERATURES ON MONDAY WILL ALSO PUSH INTO THE
60S...AND LIKELY WELL INTO THE 60S IN THE FAVORED DOWNSLOPE
LOCATIONS FROM ROCHESTER ACROSS THE NORTHERN FINGER LAKES.

THE STRONG COLD FRONT WILL PUSH THROUGH THE AREA BY MONDAY
EVENING...AND WILL LIKELY RESULT IN A LINE OF PRECIPITATION MOVING
ACROSS THE FORECAST AREA...BRINGING AN ADDITIONAL 0.10 OR SO OF QPF.

TUESDAY WILL BE MUCH COOLER WITH HIGH TEMPERATURES RUNNING IN THE
UPPER 30S TO LOWER 40S...AND WILL CONTINUE TO BE FAIRLY WINDY BEHIND
THE MONDAY NIGHTS COLD FRONT PASSAGE...HOWEVER WINDS WILL LIKELY
REMAIN BELOW HIGH WIND CRITERIA.

SNOW MELT AND FLOODING POTENTIAL...
THE WARM UP AND PRECIPITATION EVENTS ARE STILL ON TRACK AND APPEAR
FAVORABLE TO PRODUCE FLOODING FROM THE SNOW MELT. ONCE SURFACE
DEWPOINTS RISE ABOVE FREEZING SUNDAY THE RIPENING SNOW PACK WILL
BEGIN TO LET LOOSE WITH RAPID SNOW MELT ACROSS AREAS WHICH RECEIVED
LAST WEEKS HEAVY LAKE EFFECT SNOWFALL. SNOW DEPTH MEASUREMENTS FROM
FRIDAY INDICATED SNOW PACK HAS COMPACTED DOWN TO BETWEEN 20 AND 40
INCHES WITH AN AVERAGE OF 4-6 INCHES OF LIQUID LOCKED UP. SNOW MELT
MODELING COVERING A TIME RANGE FROM LATER SUNDAY THROUGH MONDAY
INDICATED 50 INCHES OF SNOW COULD MELT UNDER FORECASTED CONDITIONS.
THEREFORE...ALL OF THE EXISTING SNOW PACK IS EXPECTED TO MELT AWAY
RAISING THE CONCERNS FOR FLOODING WITH FINER DETAILS HIGHLIGHTED IN
THE FLOOD WATCH AND HYDROLOGY SECTION BELOW.

HIGH WINDS...
ADDED A HIGH WIND WATCH FOR PORTIONS OF WESTERN NEW YORK TO
HIGHLIGHT THE HIGH WIND THREAT ON MONDAY. THE STRONG SOUTHEASTERLY
850MB JET MONDAY NIGHT IS FAVORABLE FOR STRONG DOWNSLOPE WINDS ALONG
THE LAKE ERIE SHORE AND ALONG OTHER NORTHWARD FACING SLOPES IN
WESTERN NY AND THE FINGER LAKES...AND POSSIBLY THE BLACK RIVER
VALLEY. FOLLOWING THE PASSAGE OF THE WARM FRONT THE LOW LEVEL JET
VEERS TO SOUTHWEST WHICH IS MORE FAVORABLE FOR WIDESPREAD STRONG
WINDS AS WIND ENERGY FROM 50-60KT 850MB WINDS MIX DOWN.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
TEMPERATURES WILL RETURN TO BELOW AVERAGE FOR THE BULK OF NEXT WEEK
INCLUDING THE THANKSGIVING HOLIDAY AS A DEVELOPING RIDGE OVER THE
ROCKIES WILL FORCE A DOWNSTREAM TROUGH TO CARVE INTO THE GREAT LAKES
AND NORTHEAST. THE AIRMASS LOOKS TO BE COLD ENOUGH TUESDAY/WEDNESDAY
FOR A RETURN OF CHANCES FOR LAKE EFFECT SNOW AS LAKE INDUCED
EQUILIBRIUM LEVELS CLIMB TO AROUND 10KFT. AT THIS POINT IT DOES NOT
LOOK UNSTABLE ENOUGH FOR A SIGNIFICANT EVENT.

THE MID LEVEL TROUGH AND A WEAK SURFACE LOW/SURFACE TROUGH MAY BRING
A FEW SNOW SHOWERS FOR THANKSGIVING THURSDAY BEHIND A POSSIBLE
NOREASTER` LIFTING ALONG THE EAST COAST. A FRESH BLAST OF COLD AIR
BEHIND THE WEAK LOW/SURFACE TROUGH LOOKS TO THEN AGAIN BRING RENEWED
CHANCES OF LAKE EFFECT FRIDAY INTO SATURDAY.

&&

.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
CONDITIONS HAVE IMPROVED TO VFR ACROSS THE MAJORITY OF THE TERMINALS
WITH THE EXCEPTION OF KART THIS MORNING AS THE INITIAL ROUND OF
SHOWERS HAS DEPARTED TO THE EAST...HOWEVER ANOTHER AREA OF
PRECIPITATION CURRENTLY OVER NRN OH IS EXPECTED TO TRACK ACROSS
PORTIONS OF WESTERN AND NORTH CENTRAL NEW YORK LATER THIS
MORNING...POTENTIALLY BRINGING ANOTHER PERIOD OF MVFR CONDITIONS.

A STRENGTHENING LOW LEVEL JET AHEAD OF A RAPIDLY DEEPENING LOW
PRESSURE SYSTEM OVER THE CENTRAL MS VALLEY WILL LEAD TO STRONG
DOWNSLOPING WINDS AND LOCALIZED TURBULENCE ALONG THE LAKE ERIE
SHORELINE TONIGHT WITH LLWS DEVELOPING ELSEWHERE AS A STRONG LLJ
MOVES OVERHEAD IN ADVANCE OF THE AFOREMENTIONED LOW.

OUTLOOK...
SUNDAY THROUGH MONDAY...PERIODS RAIN WITH MAINLY MVFR/VFR CIGS.
SIGNIFICANT LLWS POSSIBLE SUNDAY NIGHT AND INTO MONDAY MORNING.
TUESDAY...MAINLY VFR WITH A CHANCE OF RAIN/SNOW SHOWERS.
WEDNESDAY AND THURSDAY...MAINLY VFR/MVFR EXCEPT IFR POSSIBLE IN LAKE
EFFECT SNOW SHOWERS EAST OF BOTH LAKES.

&&

.MARINE...
WINDS HAVE DIMINISHED OVERNIGHT ON THE LAKES AND HAVE CANCELLED OR
ALLOWED TO EXPIRE ALL REMAINING ADVISORIES. THE RESPITE WILL BE
SHORT-LIVED HOWEVER AS SOUTH-SOUTHEASTERLY WINDS WILL FRESHEN ON
LAKE ERIE LATER TONIGHT AS A WARM FRONT LIFTS NORTH ACROSS THE
REGION AHEAD OF A RAPIDLY DEEPENING LOW PRESSURE SYSTEM THAT WILL
TRACK FROM THE CENTRAL MISSISSIPPI VALLEY ACROSS THE WESTERN GREAT
LAKES. THIS LOW WILL CONTINUE TO INTENSIFY AS IT CROSSES THE OTTAWA
VALLEY AND MOVES INTO QUEBEC MONDAY EVENING WHILE SWINGING A STRONG
COLD FRONT ACROSS THE LOWER GREAT LAKES. GALE WATCHES REMAIN IN
EFFECT FOR EASTERN LAKE ERIE AND LAKE ONTARIO FROM MONDAY THROUGH
TUESDAY DUE TO THE VERY STRONG WIND FIELD ACCOMPANYING THIS DEEP LOW.

GALES WILL SUBSIDE LATER ON TUESDAY AS THE LOW PRESSURE SYSTEM
RESPONSIBLE TRACKS OFF TO THE NORTHEAST ACROSS LABRADOR. A WEAK AREA
OF HIGH PRESSURE IS THEN EXPECTED TO SKIRT THE LAKES WITH LIGHTER
WINDS EXPECTED FOR THE MIDDLE PORTION OF THE WEEK BEFORE NORTHERLY
WINDS FRESHEN THURSDAY NIGHT AS A DEEPENING COASTAL LOW TRACKS UP
THE EASTERN SEABOARD.

&&

.HYDROLOGY...
A SNOW SURVEY WAS COMPLETED FRIDAY TO GET SNOW DEPTH AND SNOW WATER
EQUIVALENTS FROM THE HARDEST HIT AREAS. THE SURVEY CAME UP WITH A
GENERAL 4 TO 6 INCHES OF SWE IN THE HARDEST HIT AREAS. SEE
BUFPNSBUF FOR THE SPECIFICS.

TEMPERATURES WILL RISE TO NEAR 50 ON SUNDAY...THEN INTO THE LOWER
60S ON MONDAY WITH VERY MILD LOWS SUNDAY NIGHT. DEW POINTS ARE
ALREADY WELL ABOVE 32 THIS EVENING AND WILL CONTINUE TO STEADILY RISE
INTO THE UPPER 40S TO AROUND 50 BY SUNDAY NIGHT AND MONDAY. THE
HIGHER DEWPOINTS COMBINED WITH STRONG WINDS WILL BE VERY EFFICIENT
AT RAPIDLY MELTING THE DEEP SNOW PACK. THIS...ALONG WITH RAINFALL
AMOUNTS OF GENERALLY UNDER A QUARTER INCH THROUGH SUNDAY
NIGHT...WILL RESULT IN SIGNIFICANT RISES ON LOCAL TRIBUTARIES WITH
AREAL FLOODING EXPECTED FOR THE AREAS IN FAR WESTERN NEW YORK THAT
RECEIVED THE TWO LAKE EFFECT SNOW STORMS THIS PAST WEEK.

THE FLOOD POTENTIAL WILL BE TWO FOLD. FIRST...THERE IS A GENERAL
RISK OF URBAN FLOODING IN THE TOWNS HARDEST HIT BY THE SNOW AS
MELT WATER POOLS IN LOW LYING AND POOR DRAINAGE AREAS. EXCESSIVE
SNOW PILES AND LEAVES BENEATH THE SNOW MAY BLOCK STORM DRAINS.
FLOODING OF SOME STREETS AND RESIDENTIAL BASEMENTS COULD BEGIN AS
EARLY AS THIS EVENING....SO HAVE ISSUED AN AREAL FLOOD WARNING
THROUGH AT LEAST MONDAY AFTERNOON TO ADDRESS THIS THREAT.

THERE WILL ALSO BE THE RISK FOR THE FLOODING OF THE VARIOUS
TRIBUTARIES ACROSS FAR WESTERN NEW YORK. THE GREATEST THREAT IS
ON THE BUFFALO CREEKS WHICH DRAIN THE HARDEST HIT AREAS FROM THIS
WEEKS LAKE EFFECT SNOW. THIS INCLUDES CAZENOVIA...BUFFALO...
CAYUGA...AND ELLICOTT. INDIVIDUAL FLOOD WARNINGS FOR THESE CREEKS
HAVE BEEN ISSUED...AS ALL ARE NOW FORECAST TO REACH AT LEAST MINOR
FLOOD LEVELS. THERE MAY ALSO BE SOME FLOOD RISK FOR CATTARAUGUS
CREEK AND SOME OF THE SMALLER CREEKS THAT FLOW THROUGH DUNKIRK AND
SILVER CREEK.

THERE IS ALSO A FAIRLY HEAVY SNOW PACK IN THE UPPER REACHES OF THE
OATKA WATERSHED...BUT NOT AS HIGH AS THE BUFFALO CREEKS. WE WILL
CONTINUE TO MONITOR THIS BASIN FOR POSSIBLE FUTURE INCLUSION IN
THE FLOOD WATCH. THE EASTERN LAKE ONTARIO REGION HAD LESS SNOW...
WITH TOTALS OF 2 TO 2.5 FEET ON THE TUG HILL. THIS SNOW PACK IS NOT
EXCESSIVE FOR THAT AREA...SO HAVE NOT INCLUDED THE NORTH COUNTRY
IN A FLOOD WATCH AT THIS TIME.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...HIGH WIND WATCH FROM MONDAY MORNING THROUGH MONDAY EVENING FOR
     NYZ001>003-010>012-019-085.
     WIND ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST MONDAY FOR
     NYZ019-085.
MARINE...GALE WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR
         LEZ040-041.
         SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EST
         MONDAY FOR LEZ040-041.
         GALE WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
         EVENING FOR LOZ042>045-062>065.

&&

$$

SYNOPSIS...WOOD
NEAR TERM...WOOD
SHORT TERM...CHURCH
LONG TERM...CHURCH
AVIATION...WOOD
MARINE...WOOD
HYDROLOGY...HITCHCOCK/RSH








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