Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 231231
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
731 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/...
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 FEW HUNDREDTHS OF AN INCH OF RAINFALL AT BEST AS IT
CROSSES 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 DURING THIS PERIOD REMAIN: 1) FLOODING ASSOCIATED
WITH WARM TEMPERATURES MELTING THE LAKE EFFECT SNOW AND 2) A
POSSIBLE HIGH WIND EVENT ON MONDAY AND MONDAY NIGHT.

COMPLEX DOUBLE BARRELED LOW PRESSURE WILL SHIFT ACROSS THE UPPER
GREAT LAKES MONDAY JUST TO THE WEST OF NEW YORK. EARLY MONDAY A
SHARP WARM FRONT SHOULD BE SHIFTING NORTH OF LAKE ONTARIO WITH RAIN
SHOWERS ALONG THE FRONT QUICKLY SHIFTING OFF TO THE NORTHEAST. A DRY
SLOT AND STRENGTHENING JET ALOFT WILL PUSH ACROSS WESTERN AND
CENTRAL NEW YORK WITH MOST LIKELY DRY CONDITIONS EXPECTED IN THE
AFTERNOON BUT COULD NOT QUITE RULE OUT A LOW CHANCE OF VERY PATCHY
SHOWERS WITHIN THE WARM SECTOR. DEEP SOUTHERLY FLOW WILL HELP
SURFACE TEMPERATURES TO RISE WELL ABOVE NORMAL INTO THE LOW 60S
BY EARLY AFTERNOON. A 950MB INVERSION SHOULD PREVENT ANY STRONG WIND
GUSTS FROM A 50-60KT LOW LEVEL JET FROM MIXING DOWN AND KEEP THE
POTENTIAL FOR WARMER SURFACE TEMPS IN CHECK UNTIL THE COLD FRONT ARRIVES.

SNOW MELT AND FLOODING POTENTIAL...
THIS WARM UP WILL CONTINUE THE RAPID SNOWMELT ACROSS AREAS WHICH
RECEIVED LAST WEEKS HEAVY LAKE EFFECT SNOWFALL. SNOW CORE
MEASUREMENTS FROM FRIDAY SHOWED THE SNOW PACK HAS AN AVERAGE OF 4-6
INCHES OF LIQUID LOCKED UP. SNOW MELT MODELING COVERING A TIME RANGE
FROM LATER TODAY 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 WARNING AND HYDROLOGY
SECTION BELOW. RIVER FLOODING IS ALSO LIKELY AT LEAST TO MINOR
STAGES SO RIVER FLOOD WARNINGS REMAIN IN EFFECT FOR BUFFALO CREEKS.

MODELS ARE SHOWING THE SYSTEMS COLD FRONT WILL CROSS OUR FORECAST
AREA MONDAY EVENING. THIS FRONT WILL BRING ANOTHER LIKELIHOOD OF
SHOWERS BUT THE BIGGEST CONCERN WILL BE WITH COLD ADVECTION ALLOWING
WIND ENERGY FROM A NOW STRONGER 60-75KT LOW LEVEL JET ALOFT TO BEGIN
MIXING DOWN TO THE SURFACE. THE LOW LEVEL INVERSION WILL ERODE WITH
THE COLD ADVECTION AND SURFACE WIND GUSTS SHOULD INCREASE. A HIGH
WIND WATCH REMAINS FOR A PORTION OF WESTERN NEW YORK COUNTIES WHICH
TYPICALLY SEEN HIGHER WIND GUSTS WHEN STRONG CUTTER LOWS PASS TO THE
WEST. HAVE HELD OFF ON THE DECISION TO GO WITH A WARNING VERSES
STICKING WITH A WIND ADVISORY FOR THIS SHIFT BUT WOULD AT LEAST
EXPECT ALL COUNTIES TO SEE ADVISORY LEVEL WIND GUSTS WITH THE BEST
POTENTIAL FOR WARNING LEVEL WIND GUSTS BEING THE COUNTIES UNDER THE
WATCH. CIPS ANALOGS FOR THIS PERIOD INDICATE THAT SIMILAR PATTERNS
HAVE SHOWN THE POTENTIAL FOR WIND GUSTS OVER 50KTS WHICH WOULD
INCREASE CONFIDENCE HOWEVER EXACTLY WHICH COUNTIES IS STILL MORE
UNCERTAIN AND WILL DEPEND ON THE EXACT TRACK OF THE STRONG LOW.

COLD AIR ADVECTION WILL CONTINUE TO DRIVE DOWN TEMPERATURES ON
TUESDAY AND TUESDAY NIGHT BEHIND THE COLD FRONT. GUSTY WINDS MAY
CONTINUE TO BE ELEVATED INTO PART OF TUESDAY AS THE LOW LEVEL JET IS
SLOW TO EXIT. 850MB TEMPS WILL STEADILY FALL BACK TO AROUND -10C BY
LATE TUESDAY WHICH WILL BRING AN INCREASE IN LAKE-850 INSTABILITY.
LAKE INDUCED EQUILIBRIUM LEVELS WILL RISE TO 8KFT AND A SECONDARY COLD
FRONT DROPPING ACROSS THE LOWER GREAT LAKES WILL BRING AN INCREASE
LOW LEVEL MOISTURE FOR THE DEVELOPMENT OF SOME LAKE EFFECT SNOW
BANDS EAST OF THE LAKES BY LATER TUESDAY AND TUESDAY NIGHT. SURFACE
TEMPERATURES ON TUESDAY MAY FALL INTO THE 30S THROUGH THE DAY WITH
CONTINUED COLD ADVECTION THEN DOWN INTO THE 20S TUESDAY NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
TEMPERATURES WILL REMAIN 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 WILL REMAIN COLD ENOUGH WEDNESDAY TO
CONTINUE CHANCES OF LAKE EFFECT SNOW. AT THIS POINT IT DOES NOT LOOK
UNSTABLE ENOUGH FOR A SIGNIFICANT EVENT.

THE MID LEVEL TROUGH AND A WEAK COLD FRONT/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 /13Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS CONTINUE TO PREVAIL ACROSS THE MAJORITY OF THE
TERMINALS WITH THE EXCEPTION OF KART THIS MORNING...WHICH IS SHOWING
GRADUAL IMPROVEMENT AND REMAINS MVFR. EXPECT CONTINUED IMPROVEMENT
TO VFR ACROSS THE FORECAST AREA TODAY IN SPITE OF AN AREA OF
WEAKENING SHOWERS CURRENTLY CROSSING INTO SW NY FROM NRN OH.
UPSTREAM OBS INDICATE VFR CONDITIONS IN THIS AREA OF SHOWERS AND
GIVEN MODEL TRENDS SUGGESTING THAT THE SHOWERS WILL CONTINUE TO
WEAKEN AS THEY CROSS WNY BETWEEN 15-19Z...SEE NO NEED TO DEVIATE FROM
THE VFR FORECAST.

LATER THIS EVENING...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 WITH LLWS DEVELOPING ELSEWHERE AS A STRONG
LLJ MOVES OVERHEAD IN ADVANCE OF THE AFOREMENTIONED LOW. THE NOSE OF
THIS JET WILL ALSO MARK THE LEADING A BROADER AREA OF RAINFALL
PROGGED TO MOVE INTO THE FORECAST AREA AFTER 06Z...BRINGING MVFR
CONDITIONS.

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...
WHILE WINDS HAVE DIMINISHED ON THE LAKES THIS MORNING...THE RESPITE
WILL BE SHORT-LIVED 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.
THESE SOUTHEASTERLY WINDS WILL AFFECT THE LAKE ERIE NEARSHORE
WATERS...LEADING TO ANOTHER ROUND OF SMALL CRAFT ADVISORIES FROM
BUFFALO TO RIPLEY TONIGHT. 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 COMPLETED ON FRIDAY CAME UP WITH A GENERAL 4 TO 6
INCHES OF SNOW WATER EQUIVALENT IN THE HARDEST HIT LAKE EFFECT
SNOW AREAS.

TEMPERATURES WILL RISE TO NEAR 50 TODAY...REMAIN VERY MILD TONIGHT
ONLY FALLING INTO THE MID 40S THEN RISING INTO THE 60S ON MONDAY.
DEW POINTS ACROSS THE REGION ARE ABOVE 32 AND WILL CONTINUE TO
STEADILY RISE INTO THE UPPER 40S TO AROUND 50 BY TONIGHT 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
TONIGHT...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
ANYTIME NOW WITH MELTING UNDER WAY....SO AN AREAL FLOOD WARNING
CONTINUES THROUGH AT LEAST MONDAY AFTERNOON TO ADDRESS THIS
THREAT.

THERE WILL ALSO BE THE RISK FOR THE FLOODING OF THE VARIOUS
CREEKS AND 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
A FLOOD WARNING IF WE SEE STEADY RISES. 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...SMITH
LONG TERM...SMITH
AVIATION...WOOD
MARINE...WOOD
HYDROLOGY...HITCHCOCK/RSH/SMITH






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