Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 260544
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
144 AM EDT THU MAR 26 2015

.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL BRING A ROUND OF PRECIPITATION
TODAY WHICH WILL START AS RAIN BUT MIX WITH WET SNOW AS COOLER
AIR BUILDS IN BEHIND THE SYSTEM. WINTER-LIKE WEATHER WILL RETURN FRIDAY
WITH BELOW NORMAL TEMPERATURES AND SOME SNOW SHOWERS.

&&

.NEAR TERM /THROUGH TODAY/...
THE MAINLY DRY WEATHER SHOULD CONTINUE OVERNIGHT WITH THE MAIN
FORECAST CHALLENGE HOW MUCH CLOUD COVER THERE WILL BE. DESPITE THE
DRIER AIR ALOFT...THE 00Z BUF SOUNDING SHOWS MOISTURE BENEATH 2K FT
WHICH IS PROBABLY BEING ENHANCED BY THE MOIST AIR MOVING ACROSS THE
ICE ON LAKE ERIE. THIS MAY RESULT IN A LOW STRATUS DECK IN SPOTS AS
DEPICTED BY THE HRRR AND NAM BUFKIT. OTHERWISE...EXPECT SOME
LINGERING MID AND HIGH CLOUDS WITH THE DEPARTING SYSTEM. IF SKIES
CLEAR LONG ENOUGH...SOME PATCHY FOG IS POSSIBLE.
OTHERWISE...TEMPERATURES SHOULD VERY SLOWLY DROP INTO THE MID TO
UPPER 30S LATE TONIGHT.

18-21Z NAM/GFS/SREF GUIDANCE HAS CONTINUED THE COOLING
TREND...WHICH INCREASES THE LIKELIHOOD THAT PRECIPITATION WILL MIX
WITH SNOW ON THURSDAY. PRECIPITATION WILL PROBABLY START AS
RAIN WITH A CONSENSUS QPF OF ABOUT A HALF INCH. TEMPERATURES WILL
COOL AS A COLD FRONT GRADUALLY SLIDES EAST OF THE REGION DURING
THE DAY WHEN LOW PRESSURE TRACKS ALONG THE FRONT AND PASSES SOUTH
OF THE REGION DURING THE DAY. SNOW WILL MIX IN FIRST IN NORTHERN
AND WESTERN PORTIONS OF THE CWA...INCLUDING THE NIAGARA
FRONTIER...EASTERN LAKE ONTARIO REGION...AND FAR WESTERN PORTIONS
OF THE SOUTHERN TIER. ACCUMULATION SHOULD BE LIGHT DUE TO THE
NEAR OR SLIGHTLY ABOVE FREEZING TEMPERATURES...BUT A WET INCH OR
TWO IS POSSIBLE IN STEADIER SNOWS MAINLY ON GRASSY SURFACES OR
ACROSS HIGHER TERRAIN.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
WHILE THE CONCERN DURING THE DAYS LEADING UP TO THIS PERIOD HAS BEEN
FOR ENOUGH RAIN TO CAUSE SOME FLOODING...THERE IS NOW A SUGGESTION
BY THE VARIOUS GUIDANCE PACKAGES THAT ENOUGH COLD AIR COULD MAKE IT
FAR ENOUGH SOUTH OF LAKE ONTARIO TO SUPPORT SOME ACCUMULATING SNOW.

THE STEADIEST AND HEAVIEST PCPN WILL HAVE MOVED OFF TO OUR EAST BY
THE START OF THIS PERIOD...BUT WE WILL STILL BE UNDER THE INFLUENCE
OF A VERY WET STORM SYSTEM. AN ELONGATED SFC LOW WILL MAKE ITS WAY
ACROSS NEW ENGLAND THURSDAY NIGHT...TAKING WITH IT THE DEEP LIFT
THAT WAS SUPPLIED BY A PAIR OF 150KT H25 JETLETS AND STRONG H925-70
FRONTOGENETIC FORCING FOUND WITHIN 100 MILES OR SO NORTH OF THE SFC
LOW TRACK. REMOVING THIS LIFT WHILE INTRODUCING MID LEVEL DRYING AND
SOME LOW LEVEL RIDGING WILL LEAD TO MIXED RAIN AND SNOW TAPERING OFF
TO SNOW SHOWERS DURING THE FIRST HALF OF THE NIGHT...WITH ONLY
NUISANCE SNOW SHOWERS EXPECTED DURING THE OVERNIGHT. ADDITIONAL QPF
WILL RANGE FROM LESS THAN A TENTH OF AN INCH OVER THE WESTERN
COUNTIES TO A COUPLE TENTHS OVER THE EASTERN LAKE ONTARIO REGION.
TOTAL RAINFALL FROM THE 12 HOUR EVENT WILL RANGE FROM A HALF TO
THREE QUARTERS OF AN INCH.

AS HAS BEEN ADVERTISED FOR SEVERAL DAYS...THIS AMOUNT OF RAINFALL
ALONG WITH CONTINUED SNOWMELT COULD LEAD TO PROBLEMS ON SOME
TRIBUTARIES...ESPECIALLY THE THREE MAIN WATERWAYS IN THE BUFFALO
AREA (CAZENOVIA, CAYUGA, BUFFALO CREEKS). FOR MORE INFORMATION ON
POTENTIAL HYDROLOGIC CONCERNS SEE THE HYDROLOGY SECTION BELOW.

ON FRIDAY...A SECONDARY COLD FRONTAL TROUGH WILL PUSH SOUTH ACROSS
THE LOWER GREAT LAKES. THIS WILL SUPPORT SCATTERED SNOW SHOWERS WITH
A BETTER CHANCE FOR STEADIER SNOWS ACROSS THE HIGHER TERRAIN IN THE
FAVORABLE COLD AIR ADVECTION/UPSLOPE REGIME. ACCUMULATIONS SHOULD BE
UNDER AN INCH...BUT HIGHER AMOUNTS WILL NOT BE OUT OF THE QUESTION
WEST OF THE FINGER LAKES. TEMPERATURES FRIDAY SHOULD BE A SOLID 10
DEG LOWER THAN THOSE FROM THE PREVIOUS DAY...AS MAX TEMPS ARE ONLY
EXPECTED TO TOP OUT WITHIN A COUPLE DEGREES OF FREEZING.

THE UPSLOPE...CYCLONIC FLOW WILL DELAY ANY REAL CLEARING FRIDAY
NIGHT AS THE MAIN UPPER LEVEL TROUGH WILL SWING ACROSS THE LOWER
GREAT LAKES. THERE SHOULD STILL BE SOME SCATTERED SNOW SHOWERS OVER
THE WESTERN COUNTIES...MAINLY WEST OF THE FINGER LAKES WHERE THE LOW
LEVEL FLOW WILL BE MORE CONDUCIVE FOR A LITTLE LAKE ENHANCEMENT OFF
ONTARIO. EVEN SO...ACCUMULATIONS WILL LIKELY BE MEASURED IN TENTHS
RATHER THAN INCHES. MEANWHILE...CONTINUED COLD ADVECTION SHOULD SEND
OVERNIGHT TEMPERATURES INTO THE TEENS AND PERHAPS EVEN THE SINGLE
DIGITS ACROSS PORTIONS OF THE SOUTHERN TIER AND EAST OF LAKE ONTARIO.

A SPRAWLING ARCTIC HIGH WILL DRIFT FROM THE UPPER GREAT LAKES TO THE
OHIO VALLEY ON SATURDAY. THIS WILL GUARANTEE AN ANOMALOUSLY COLD DAY
ACROSS OUR FORECAST AREA...AS TEMPERATURES ARE ONLY PROJECTED TO
REACH INTO THE MID AND UPPER 20S. THESE VALUES WILL BE SOME 20 DEG
BELOW NORMAL LATE MARCH VALUES. WHILE THE COLD AIR MAY BE
ACCOMPANIED BY SOME RESIDUAL LIGHT SNOW SHOWERS IN THE MORNING...
SKIES SHOULD CLEAR DURING THE COURSE OF THE DAY. THE INCREASED SUN
SHOULD HELP TO TEMPER AN OTHERWISE LATE JANUARY THERMOMETER.

ON SUNDAY...HIGH PRESSURE NOSING NORTH FROM THE MID ATLANTIC STATES
WILL KEEP OUR FORECAST AREA PCPN FREE. THE INCREASED SOUTHERLY FLOW
ON THE BACKSIDE OF THE SFC HIGH WILL PROMOTE NOTABLY MILDER
CONDITIONS AS WELL...WITH TEMPERATURES EXPECTED TO REACH THE LOWER
40S FOR MANY AREAS. A SHORTWAVE DROPPING SOUTHEAST ACROSS THE LOWER
GREAT LAKES SUNDAY NIGHT WILL THEN INTRODUCE THE NEXT ROUND OF SNOW
SHOWERS TO THE REGION.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
A PROGRESSIVE...LOW AMPLITUDE PATTERN WILL BE IN PLACE ACROSS THE
COUNTRY DURING THIS PERIOD...WITH A PARADE OF PACIFIC BASED
SHORTWAVES CROSSING THE GREAT LAKES REGION. WHILE TEMPERATURES WILL
BE COMFORTABLY HIGHER THAN THOSE EXPERIENCED THE PAST COUPLE
WEEKS...THE MERCURY WILL STILL AVERAGE A FEW DEGREES BELOW LATE
MARCH NORMALS.

DEEP LOW PRESSURE WILL PASS BY TO OUR NORTH TO OPEN THIS PERIOD.
WHILE THE MAIN COLD FRONT ASSOCIATED WITH THIS FEATURE IS FORECAST
TO MOVE THROUGH OUR REGION SUNDAY NIGHT...A SECONDARY COLD FRONT
WILL MOVE THROUGH DURING THE DAY MONDAY. THE MINIMAL SYNOPTIC
FORCING FROM THIS FEATURE WILL COMBINE IN THE UNSTABLE CHILLY
AIRMASS TO PRODUCE SOME RAIN AND WET SNOW SHOWERS...ALTHOUGH THE
BULK OF THE DAY WILL LIKELY BE PCPN FREE. IT IS NOT EXPECTED TO BE
COLD ENOUGH TO GET ANY LAKE ENHANCEMENT IN THIS EVENT.

ON TUESDAY...A ROBUST SHORTWAVE IS FORECAST TO TRACK FROM THE MID
WEST AND LOWER OHIO VALLEY TO THE MID ATLANTIC REGION. WHILE THE
BASE OF THE SUPPORTING LONGWAVE TROUGH CROSS OUR REGION...THE
RESULTING SYNOPTIC FORCING IS NOT EXPECTED TO BE STRONG ENOUGH TO
WARRANT ANYTHING MORE THAN SLGT CHC POPS FOR RAIN SHOWERS.

A BURGEONING RIDGE WILL THEN CROSS THE LOWER GREAT LAKES TUESDAY
NIGHT AND WEDNESDAY. WHILE THIS WILL LEAD TO MORE WARMING...THERE
WILL ALSO BE THE CHANCE FOR SOME SHOWERS AHEAD OF THE NEXT COLD
FRONTAL BOUNDARY.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
THERE IS A LOT OF MOISTURE IN THE LOWEST 2KFT DUE TO MOIST AIR
MOVING ACROSS THE COLD OR FROZEN LAKES. THIS MAY RESULT IN IFR CIGS
AND FOG NORTHEAST OF THE LAKES BUT THIS WILL BE DIFFICULT TO TIME.
EXPECT SLIGHTLY DRIER AIR AND DIMINISHING WINDS LIKELY TO RESULT IN
IMPROVING CONDITIONS LATE TONIGHT.

THIS IMPROVEMENT SHOULD BE SHORT LIVED AS ANOTHER WAVE OF LOW
PRESSURE TRACKS TO THE SOUTH AND BRINGS ABOUT 6 HOURS OF STEADY
PRECIPITATION DURING THE DAY THURSDAY. TEMPERATURES ALOFT WILL
LIKELY BE COLD ENOUGH FOR RAIN TO MIX WITH SNOW. THIS SHOULD LOWER
CIGS TO IFR OR LOWER...BUT THE WET SNOW AND RAIN MIX WILL PROBABLY NOT
LOWER VSBY AS MUCH AS AN EVENT WITH COLDER TEMPERATURES. CONDITIONS
WILL IMPROVE FROM SW-NE LATE IN THE DAY AS THE SYSTEM EXITS.

OUTLOOK...
THURSDAY NIGHT THROUGH FRIDAY NIGHT...MVFR WITH A CHANCE OF SNOW
SHOWERS.
SATURDAY AND SUNDAY...VFR.
MONDAY...MVFR IN RAIN/SNOW SHOWERS.

&&

.MARINE...
WEST TO NORTHWEST WINDS LATER THIS WEEK WILL INCREASE BEHIND A COLD
FRONT WITH SMALL CRAFT CONDITIONS POSSIBLE ON THE OPEN WATERS OF
LAKE ONTARIO LATER FRIDAY NIGHT.

&&

.HYDROLOGY...
A WARM FRONT BROUGHT ABOUT A TENTH OF AN INCH OF RAIN TO THE
RIVER AND CREEK BASINS. HIGH TEMPERATURES WERE ONLY IN THE LOWER TO MID
40S...AND EVEN A BIT COOLER THAN THAT IN THE SOUTHERN TIER. AS A
RESULT THE CREEK AND RIVER RESPONSE WILL PROBABLY BE A BIT LESS
THAN WHAT WAS EXPECTED.

THERE IS ANOTHER WAVE OF LOW PRESSURE WHICH SHOULD BRING ABOUT
ANOTHER HALF INCH OF QPF. HOWEVER...GUIDANCE HAS CONTINUED TO
TREND COLDER WITH THIS SYSTEM. TEMPERATURES ON THURSDAY MAY ONLY
BE IN THE UPPER 30S WHICH WOULD REDUCE RUN-OFF FROM SNOW MELT. THE
COOLER TEMPERATURE FORECAST HAS ALSO LOWERED THE EXPECTED THAWING
DEGREE HOURS TO ABOUT 250 TO 300.

ALTHOUGH THIS SHIFT IN MODEL GUIDANCE HAS DIMINISHED THE THREAT
FOR FLOODING...THE THREAT IS NOT COMPLETELY GONE. THERE WILL BE
SHARPLY WARMER AIR JUST TO THE SOUTH OF THE REGION...AND ANY
NORTHWARD SHIFT IN THIS WARM AIR COULD DRAMATICALLY INCREASE RUN-
OFF AND FLOWS. THERE IS ALSO QUITE A BIT OF ICE ALONG THE SHORES
OF THE CAZENOVIA AND BUFFALO CREEKS. IF LEVELS RISE TO ACTION
STAGE...THIS COULD CAUSE THIS ICE TO FLOAT AND BECOME JAMMED.
BECAUSE OF THIS...WE WILL CONTINUE TO KEEP A CLOSE EYE ON THE
SITUATION. IT IS STILL POSSIBLE THAT FLOOD WATCHES WILL BE NEEDED
FOR A PORTION OF THE AREA...ESPECIALLY IF THE LOW TAKES EVEN A
SLIGHTLY MORE NORTHWARD TRACK THAN WHAT IS CURRENTLY FORECAST.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...APFFEL/WCH
NEAR TERM...APFFEL/WCH
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...APFFEL
MARINE...CHURCH/WCH
HYDROLOGY...APFFEL/WCH






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