Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 150842
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
442 AM EDT TUE APR 15 2014

.SYNOPSIS...
A SHARP COLD FRONT WILL SLOWLY FINISH PUSHING ACROSS WESTERN AND
NORTH CENTRAL NEW YORK THIS MORNING...WITH PERIODS OF RAIN ALONG THE
FRONT CHANGING TO WET SNOW BEFORE GRADUALLY TAPERING OFF FROM WEST
TO EAST THIS AFTERNOON AND EVENING. HIGH PRESSURE AND DRIER AIR
BUILDING IN BEHIND THIS SYSTEM WILL THEN HELP BRING A RETURN TO DRY
WEATHER BY WEDNESDAY...THOUGH TEMPERATURES WILL REMAIN UNSEASONABLY
COLD THROUGH WEDNESDAY NIGHT BEFORE MODERATING BACK TO MORE NORMAL
LEVELS ON THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
08Z SURFACE ANALYSIS SHOWS THE SURFACE COLD FRONT DRAPED FROM THE
SAINT LAWRENCE VALLEY SOUTHWESTWARD ACROSS THE FINGER LAKES REGION
AND INTO THE WESTERN SOUTHERN TIER...THEN FURTHER SOUTHWEST TO THE
VICINITY OF THE NEXT SURFACE WAVE OVER SOUTHWESTERN PENNSYLVANIA.
WHILE AREA RADARS CONTINUE TO SHOW ONLY ISOLATED TO SCATTERED
SHOWERS ACROSS THE AREA AS OF THIS WRITING...A LARGER AREA OF MORE
WIDESPREAD RAIN ASSOCIATED WITH THE AFOREMENTIONED SURFACE WAVE
CONTINUES TO SLOWLY ENCROACH ON OUR WESTERN DOORSTEP...WITH THE
LEADING EDGE OF THIS NOW RUNNING FROM ABOUT SAINT CATHERINES ONTARIO
TO ERIE PENNSYLVANIA.

THROUGH THE COURSE OF TODAY...THE SURFACE WAVE TO OUR SOUTHWEST WILL
RIPPLE NORTHEASTWARD ALONG THE FRONTAL BOUNDARY INTO THE SAINT
LAWRENCE VALLEY...WHILE HELPING TO SHOVE THE SLOW-MOVING FRONT
EASTWARD INTO NEW ENGLAND. AS THIS OCCURS...THE LARGE AREA OF
STEADIER PRECIPITATION TO OUR WEST WILL SPREAD EASTWARD ACROSS THE
FORECAST AREA THIS MORNING...BEFORE SLOWLY DIMINISHING FROM WEST TO
EAST THIS AFTERNOON AND EVENING AS THE AXIS OF BEST SYNOPTIC-SCALE
LIFT AND DEEPEST MOISTURE DEPARTS OFF TO OUR EAST.

EXPECT BOUNDARY LAYER TEMPERATURES TO SUPPORT RAIN AT THE ONSET OF
THE STEADIER PRECIP...BEFORE STRENGTHENING COLD AIR ADVECTION TO THE
REAR OF THE FRONT FORCES A MIX WITH AND EVENTUAL CHANGEOVER TO WET
SNOW FROM WEST TO EAST. UPSTREAM OBSERVATIONAL TRENDS AND THE SHORT
TERM MODEL GUIDANCE SUGGEST THAT THIS TRANSITION WILL BEGIN EARLY
THIS MORNING WEST OF THE GENESEE VALLEY...BETWEEN LATE THIS MORNING
AND EARLY THIS AFTERNOON ACROSS THE FINGER LAKES...AND EARLY THIS
AFTERNOON ACROSS THE NORTH COUNTRY. DURING THIS TRANSITION
PERIOD...MODEL TEMPERATURE PROFILES SUGGEST THAT THERE MAY BE A
BRIEF WINDOW WHEN THE PRECIPITATION MAY BRIEFLY MIX WITH SOME SLEET
AND FREEZING RAIN... HOWEVER EVEN IF SUCH A MIX COMES TO FRUITION
EXPECT LITTLE TO NO IMPACT FROM THIS GIVEN BOTH THE HIGH MID APRIL
SUN ANGLE...AND WARMER GROUND CONDITIONS STEMMING FROM THE WARMER
WEATHER OF THE PAST 4-5 DAYS. ONCE THE PRECIP CHANGES OVER TO ALL
SNOW...EXPECT THE APRIL SUN AND WARMER GROUND CONDITIONS TO HAVE A
SIMILAR ADVERSE IMPACT ON ANY SUBSEQUENT SNOW ACCUMULATIONS...WITH
THESE LIKELY BEING LIMITED TO SLUSHY AMOUNTS OF AN INCH OR LESS ON
GRASSY/ ELEVATED SURFACES ACROSS THE LOWER ELEVATIONS...AND ACCUMS
OF 1-3" ACROSS THE HIGHER TERRAIN. WITH ALL OF THIS IN MIND...HAVE
HELD OFF ON ISSUING ANY WINTER WEATHER ADVISORIES AT THE PRESENT
TIME.

BEHIND THE STEADIER SYNOPTIC-SCALE SNOWS...EXPECT SCATTERED TO
NUMEROUS LAKE-ENHANCED/LAKE-EFFECT SNOW SHOWERS TO LINGER THROUGH
THE EVENING SOUTHEAST OF LAKE ONTARIO THIS EVENING...THANKS TO A
WEST-NORTHWESTERLY FLOW OF -15C AIR CROSSING THE LAKE AT 850 MB.
WHILE THESE WILL NOT BE LIKELY TO PRODUCE SIGNIFICANT ACCUMULATIONS
GIVEN INVERSION HEIGHTS OF ONLY AROUND 5-6 KFT...THESE COULD STILL
PUT DOWN A COUPLE OF INCHES OR SO BEFORE DIMINISHING OVERNIGHT AS
INVERSION HEIGHTS LOWER AND THE ATMOSPHERE DRIES OUT. ELSEWHERE...
SOME ADDITIONAL OROGRAPHICALLY-DRIVEN SNOW SHOWER ACTIVITY MAY
LINGER INTO THIS EVENING ACROSS THE HIGHER TERRAIN...BEFORE
SIMILARLY DYING OUT.

AS FOR TEMPS...THE MUCH COLDER AIRMASS ADVECTING IN BEHIND THE COLD
FRONT WILL RESULT IN TEMPERATURES PLUMMETING BACK TO WELL BELOW
NORMAL TODAY AND TONIGHT...WITH ALL AREAS SEEING READINGS PLUNGE
TO THE LOWER TO MID 30S BY MID AFTERNOON...BEFORE FURTHER DROPPING
TO THE MID TEENS TO LOWER 20S TONIGHT. RECORD LOWS FOR APRIL 16TH
ARE 20 IN BUFFALO...22 IN ROCHESTER...AND 25 IN WATERTOWN...AND
ALL APPEAR TO HAVE A GOOD CHANCE AT BEING BROKEN.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY...AND THEN
SHIFT INTO NEW ENGLAND WEDNESDAY NIGHT. THIS WILL BRING FAIR WEATHER
BUT CONTINUED COLD TEMPERATURES...WITH HIGHS ON WEDNESDAY ONLY IN
THE UPPER 30S TO LOWER 40S. AS THE HIGH SLIDES FURTHER EAST ON
THURSDAY...A SOUTHERLY FLOW WILL BRING IN WARMER AIR WITH MORE
SEASONABLE HIGHS IN THE 50S.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
FOLLOWING THE EXTREMES OF EARLY THIS WEEK...THE LATTER PORTION OF
THE WEEK WILL BE FAIR WITH QUITE SEASONABLE TEMPERATURES. MODEL
GUIDANCE KEEPS IT DRY THROUGH FRIDAY...WITH NEAR NORMAL
TEMPERATURES. AFTER THIS...A CONSENSUS OF THE 12Z GGEM/ECMWF/GFS ARE
A BIT FASTER WITH A CLIPPER LOW WHICH IS NOW FORECAST TO CROSS LATE
FRIDAY NIGHT INTO SATURDAY. THE GGEM IS A MOIST OUTLIER...BUT MOST
GUIDANCE IS FAIRLY WEAK WITH THE SYSTEM SUPPORTING HIGH CHANCE POPS.

AFTER THIS...A FAIRLY ZONAL FLOW BECOMES ESTABLISHED WHICH WILL
BRING SEASONABLE TEMPERATURES AND FREQUENT WEAK SYSTEMS WHICH MAY
BRING SOME LIGHT SHOWERS. CONFIDENCE IN MODEL TIMING WEAK SHORTWAVES
AT THIS TIMEFRAME IS LOW...WITH FORECAST REFLECTING AN EXTENDED
PERIOD OF LOW CHANCE POPS AND MOSTLY CLOUDY SKIES.

&&

.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
AS OF 06Z...THE SURFACE COLD FRONT WAS DRAPED FROM THE SAINT
LAWRENCE VALLEY SOUTHWESTWARD ACROSS THE FINGER LAKES REGION...AND
INTO THE WESTERN SOUTHERN TIER. SEVERAL BATCHES OF RAIN SHOWERS THAT
HAD BEEN AFFECTING THE CWA ARE NOW IN THE PROCESS OF EXITING TO OUR
NORTHEAST...WITH THE BACK EDGE OF ONE OF THESE HAVING JUST CLEARED
NIAGARA COUNTY...AND THE OTHER NOW LIFTING ACROSS THE NORTH COUNTRY.
IN THEIR WAKE...RELATIVELY SCATTERED SHOWERS WILL FOLLOW FOR A
COUPLE OF HOURS...BEFORE THE NEXT AREA OF STEADIER RAIN BEGINS
PUSHING INTO FAR WESTERN NEW YORK AFTER ABOUT 08Z. THIS SHOULD
REMAIN ALL RAIN THROUGH ABOUT 10 OR 11Z...AFTER WHICH TIME COOLING
OF THE COLUMN WILL BEGIN TO INDUCE A MIX WITH SLEET AND SNOW ACROSS
EXTREME FAR WESTERN NEW YORK. IN TERMS OF FLIGHT CONDITIONS...EXPECT
IFR TO MVFR TO PREDOMINATE THROUGH THE REMAINDER OF THE NIGHT AND
INTO THE EARLY MORNING HOURS...WITH PERHAPS A FEW AREAS OF LOW VFR
STILL MIXED IN EAST OF THE GENESEE VALLEY.

DURING THE DAYTIME HOURS OF TUESDAY...PROGRESSIVELY COLDER AIR WILL
ADVECT INTO THE BACKSIDE OF THIS SYSTEM AND FORCE RAIN TO CHANGE
OVER TO SNOW FROM WEST TO EAST. THERE MAY EVEN BE A LITTLE SLEET OR
FREEZING RAIN MIXED IN DURING THE TRANSITION PERIOD...HOWEVER
CONFIDENCE IN THIS REMAINS LOW. EXPECT LOWER VSBYS TO DEVELOP FROM
WEST TO EAST AS THE RAIN CHANGES TO SNOW...WITH CIGS GENERALLY
RUNNING IFR TO MVFR.

EXPECT THE SNOW TO TAPER OFF TO SOME SCATTERED LEFTOVER SNOW SHOWERS
TUESDAY AFTERNOON AND EVENING AS HIGH PRESSURE AND DRIER AIR BUILDS
IN BEHIND THE SLOWLY DEPARTING FRONT. THIS WILL ALLOW VSBYS TO
RETURN BACK TO VFR...THOUGH SOME MVFR CIGS WILL LINGER INTO AT LEAST
TUESDAY EVENING.

OUTLOOK...
WEDNESDAY THROUGH FRIDAY...VFR.
SATURDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.

&&

.MARINE...
IN THE WAKE OF A SLOW MOVING COLD FRONT...ADVISORY-LEVEL WINDS AND
WAVES WILL RETURN TO THE LOWER LAKES REGION TODAY...BEFORE GRADUALLY
SUBSIDING TUESDAY NIGHT AND WEDNESDAY MORNING AS HIGH PRESSURE
BUILDS INTO THE AREA FROM THE UPPER GREAT LAKES.

LOOKING A BIT FURTHER AHEAD...EXPECT MORE TRANQUIL CONDITIONS FROM
WEDNESDAY AFTERNOON RIGHT ON THROUGH FRIDAY AS THE AFOREMENTIONED
HIGH SLOWLY DRIFTS FROM NEW YORK STATE TO THE NEW ENGLAND COAST.

&&

.HYDROLOGY...
CONCERNS CONTINUE FOR PORTIONS OF THE EASTERN LAKE ONTARIO
REGION. THERE IS STILL A SIGNIFICANT SNOW PACK ON THE TUG
HILL...HOWEVER THIS HAS BEEN MELTING AND WILL CONTINUE TO
MELT THROUGH THIS MORNING. AS A RESULT...SMALLER CREEKS FED BY
THE TUG HILL AND THE HIGHER TERRAIN OF THE ADIRONDACKS WILL
CONTINUE TO FLOW NEAR BANKFULL DURING THIS PERIOD. ADDITIONALLY...
UP TO AN INCH OF RAINFALL IS EXPECTED IN THE EASTERN LAKE ONTARIO
REGION THROUGH TODAY. THIS WILL ALSO CAUSE BOTH CREEKS AND MAIN
STEM RIVERS TO RISE.

THE BLACK RIVER IS ALREADY AT FLOOD STAGE AT WATERTOWN. RAIN AND SNOW
MELT WILL PUSH THIS GRADUALLY HIGHER...WITH MORE SIGNIFICANT RISES
LIKELY FOLLOWING TODAY/S RAINS. THIS IS LIKELY TO PRODUCE MINOR
FLOODING ON THE BLACK RIVER FROM LOWVILLE TO WATERTOWN...WITH THE
RIVER LIKELY TO REMAIN ABOVE FLOOD STAGE FOR AN EXTENDED PERIOD OF
TIME...PROBABLY UNTIL THURSDAY OR FRIDAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FLOOD WATCH THROUGH LATE WEDNESDAY NIGHT FOR NYZ006>008.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 11 PM EDT
         THIS EVENING FOR LEZ020.
         SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 11 PM EDT
         THIS EVENING FOR LEZ040-041.
         SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 11
         PM EDT THIS EVENING FOR LOZ030.
         SMALL CRAFT ADVISORY UNTIL 2 PM EDT WEDNESDAY FOR
         LOZ043>045.
         SMALL CRAFT ADVISORY UNTIL 11 AM EDT WEDNESDAY FOR LOZ042.

&&

$$

SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...APFFEL/FRANKLIN
LONG TERM...APFFEL
AVIATION...JJR/THOMAS
MARINE...JJR
HYDROLOGY...APFFEL/JJR







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