Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 281800
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
100 PM EST SAT FEB 28 2015

.SYNOPSIS...
HIGH PRESSURE PASSING OVER PENNSYLVANIA WILL PRODUCE BRIGHT SUNSHINE
ACROSS THE MAJORITY OF THE REGION TODAY...WITH ONLY SOME NUISANCE
LIGHT LAKE EFFECT FLURRIES FOUND EAST OF LAKE ONTARIO. AS THE HIGH
EXITS THE EAST COAST LATE TONIGHT AND SUNDAY...A WAVY FRONTAL
BOUNDARY WILL APPROACH THE REGION. THIS NEXT SYSTEM WILL GENERATE
WIDESPREAD LIGHT ACCUMULATING SNOW DURING THE SECOND HALF OF THE
WEEKEND...WITH A LITTLE GREATER AMOUNTS ACROSS THE WESTERN SOUTHERN
TIER. A WARMER...SECOND STORM SYSTEM WILL IMPACT OUR REGION BY MID
WEEK WITH A MIXED BAG OF PRECIPITATION AND POSSIBLY SOME STRONG
WINDS.

&&

.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE CENTERED OVER PENNSYLVANIA WILL SUPPLY PLENTY OF
BRIGHT SUNSHINE ACROSS THE WESTERN COUNTIES TODAY...BUT IT WILL
REMAIN COLD. H85 TEMPS IN THE MINUS TEENS CELSIUS WILL ONLY SUPPORT
AFTERNOON HIGHS IN THE UPPER TEENS TO LOWER 20S F...AND WHILE THESE
READINGS WILL BE HIGHER THAN THE PAST FEW DAYS...IT WILL STILL BE
SOME 15 TO 20 DEG F BELOW NORMAL.

WHILE WESTERN NEW YORK WILL BASK UNDER SUNNY SKIES THIS LAST DAY OF
FEBRUARY...A COLD WESTERLY FLOW WILL KEEP LIGHT LAKE EFFECT FLURRIES
IN PLACE EAST OF LAKE ONTARIO. THIS NUISANCE ACTIVITY WILL BE
SEVERELY LIMITED BY SEVERAL FACTORS...INCLUDING A LOW CAP OF UNDER
5K FT AND SIGNIFICANT ICE COVER AT THE EAST END OF THE LAKE. ALSO
WORKING AGAINST SIGNIFICANT SNOW ACCUMS WILL BE AN INCREASINGLY
SHEARED BOUNDARY LAYER. AS A RESULT...EXPECT NOTHING MORE THAN
FLURRIES ACROSS NORTHERN OSWEGO COUNTY AND THE TUG HILL SHIFTING
NORTH INTO JEFFERSON COUNTY THIS AFTERNOON AND DISSIPATING WITH
LITTLE OR NO ACCUMULATION.

TONIGHT...THE AFOREMENTIONED SFC HIGH WILL MAKE ITS WAY TO THE EAST
EAST COAST. THIS WILL ENCOURAGE THE LOW LEVEL WINDS TO BACK TO THE
SOUTH...THUS PUSHING ANY LIGHT LAKE INDUCED FLURRIES NORTHWARD
ACROSS THE NORTHERN PORTION OF JEFFERSON COUNTY WHERE THEY WILL END
COMPLETELY BY LATE EVENING. ELSEWHERE...CLEAR SKIES OVER THE WESTERN
COUNTIES DURING THE EVENING WILL GIVE WAY TO INCREASING CLOUDS LATE
AS A WAVY FRONTAL BOUNDARY WILL APPROACH FROM THE WEST. THE
THICKENING CLOUDS OVER THE FAR WESTERN COUNTIES COULD EVEN SUPPORT
SOME LIGHT SNOW BY DAYBREAK SUNDAY.

WARM ADVECTION AHEAD OF THE ILL DEFINED BAROCLINIC ZONE WILL LEAD TO
SLOWLY RISING TEMPERATURES AFTER MIDNIGHT. AFTER REACHING OVERNIGHT
LOWS WITHIN A FEW DEGREES OF ZERO DURING THE FIRST HALF OF NIGHT...
MOST AREAS SHOULD EXPERIENCE A 5 TO 10 DEG RISE IN THE MERCURY BY
DAYBREAK.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
HIGH PRESSURE WILL MOVE OFF THE MID ATLANTIC COAST EARLY SUNDAY AND
A RETURN FLOW OF MOISTURE AND WARMER OVERRUNNING AIR WILL SET THE
STAGE FOR THE NEXT ACCUMULATING SNOW EVENT.

THE UPPER FLOW WILL BE QUASIZONAL WITH A SERIES OF DIFFUSE VORTICITY
MAXIMA...BUT THE DRIVING FORCES FOR THE SNOWFALL MAY BE FOUND IN THE
BOUNDARY LAYER AND EVEN FURTHER ALOFT AT JET STREAM LEVEL OF 300MB.

FORCING WILL ONLY INITIALLY BE ISENTROPIC WITH A BROAD REGION OF
WARM ADVECTION EARLIER SUNDAY...THEN FURTHER SUPPORTED BY A DEEPER
LAYER OF LIFT ASSOCIATED WITH THE LEFT EXIT OF A 160KT 300MB JET
STREAK OVER NORTHERN IL/IN/OH...PROVIDING ENOUGH LIFT TO SUPPORT A
WIDESPREAD LIGHT TO MODERATE SNOW FALL SUNDAY AFTERNOON AND EVENING.

WARMER PROFILES AHEAD OF THE SURFACE LOW AN EXPECTATION OF
RELATIVELY SMALL SNOWFLAKES SHOULD HOLD SNOW RATIOS DOWN TO AN
AVERAGE OF 12:1 DURING MUCH OF THE EVENT UNTIL COLDER AIR
CIRCULATES IN BEHIND THE SURFACE WAVE LATER SUNDAY NIGHT INTO
MONDAY. LATEST 12Z MODEL GUIDANCE HAS CONTINUED A SLIGHTLY WEAKER
AND FARTHER SOUTH TREND FROM MODEL GUIDANCE OF A DAY AGO...AND
THIS HAS PROMPTED FURTHER REDUCTIONS IN FORECAST SNOW AMOUNTS.
EXPECTING TOTALS OF 4-6 INCHES ACROSS THE WESTERN SOUTHERN TIER
WHERE AN ADVISORY IS IN EFFECT...WITH LESSER AMOUNTS FARTHER
NORTH.

TEMPERATURES SUNDAY WILL CLIMB TOWARD 30 THEN ONLY SLIP INTO THE
UPPER TEENS TO LOWER 20S SUNDAY NIGHT WITH FALLING SNOW AND CLOUD
COVER. WRAP AROUND MOISTURE AND DEFORMATION ON THE BACK SIDE OF THE
DEPARTING LOW ON MONDAY WILL CONTINUE CHANCES OF SOME LIMITED SNOW
TAPERING OFF THROUGH THE DAY. TEMPERATURES MONDAY WILL WARM TOWARD
THE UPPER 20S EARLY THEN FALL THROUGH THE AFTERNOON WITH THE COLD
ADVECTION BEHIND THE STORM. PACIFIC BASED HIGH PRESSURE WILL BUILD
OVER THE FORECAST AREA BEHIND THE DEPARTING STORM WITH CLEARING
SKIES GOING INTO MONDAY NIGHT. THE COLD ADVECTION...CLEAR SKIES AND
LIGHT WINDS WILL PROMOTE A RETURN TO BELOW NORMAL LOW TEMPERATURES
DROPPING TO AROUND 10.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
JUST AS WE ARE FINISHED CLEARING THE DRIVEWAYS AND SIDEWALKS FROM
SUNDAYS STORM...ANOTHER STRONGER AND WARMER STORM WILL QUICKLY
APPROACH FOR TUESDAY AND WEDNESDAY WITH A POTENTIAL FOR AN ICY MIX
FOLLOWED BY STRONG WINDS. SEVERAL STRONG SHORTWAVE DISTURBANCES WITH
ATTENDANT VORTICITY MAXIMUM WILL EJECT EASTWARD OUT OF A FULL
LATITUDE WESTERN STATES TROUGH TUESDAY TRIGGERING A RAPIDLY
DEEPENING GREAT LAKES CUTTER TYPE LOW. DEEP SOUTHERLY FLOW AHEAD OF
THIS SYSTEM WILL SPREAD A PLUME OF WARM MOIST GULF SOURCED AIR
NORTHWARD ACROSS THE OHIO VALLEY AND NORTHEAST TUESDAY NIGHT.

WHILE SNOW LOOKS TO BEGIN ARRIVING ACROSS THE FORECAST AREA TUESDAY
WITH SUB-FREEZING TEMPERATURES IN PLACE...WARM AIR ALOFT UNDER
SOUTHERLY FLOW WILL OVERRIDE COLDER SUB-FREEZING SURFACE
TEMPERATURES LATER TUESDAY INTO TUESDAY NIGHT PRODUCING A WARM NOSE
IN VERTICAL TEMPERATURE PROFILES. THIS WILL LIKELY CAUSE SNOW TO
CHANGE TO AN ICY MIX OVERNIGHT WITH SOME SECTIONS POSSIBLY EVEN
GOING OVER TO PLAIN RAIN AS TEMPERATURES PUSH TOWARD 40 DEGREES.

THE MATURE LOW WILL SHIFT JUST NORTHWEST OF WESTERN NEW YORK ON
TUESDAY NIGHT INTO WEDNESDAY WITH THE SYSTEMS COLD FRONT AND
POSSIBLE TRAILING STRONG WINDS CROSSING THE FORECAST AREA THROUGH
WEDNESDAY. AFTER A SHORT PERIOD OF PLAIN RAIN AHEAD OF THE FRONT THE
RAIN WILL MIX WITH SNOW AS THE FRONT SHIFTS EAST. THE TRACK OF THIS
DEEPENING LOW CUTTING JUST TO THE NORTHWEST IS A FAVORABLE PATTERN
FOR STRONG WINDS ACROSS OUR FORECAST AREA. MODELS SHOW A SIGNIFICANT
PRESSURE FALL-RISE COUPLET CROSSING DIRECTLY ACROSS WESTERN AND
NORTH-CENTRAL NEW YORK INDICATING THE START OF THE DOWNWARD TRANSFER
OF A 40-50KT LOW LEVEL JET JUST ABOVE THE SURFACE. THIS SYSTEM WILL
NEED TO CONTINUE TO BE CLOSELY WATCHED IN THE COMING DAYS WITH THE
WINTRY MIX AND POTENTIAL FOR STRONG WINDS. COLD AIR WILL CONTINUE TO
FILTER ACROSS THE REGION THURSDAY AND FRIDAY WITH A WESTERN CANADIAN
SOURCED HIGH WORKING ACROSS THE CENTRAL STATES. EXPECTING MAINLY DRY
DRY WEATHER TOWARD THE END OF THE WEEK WITH A RETURN TO SUB-FREEZING
TEMPS.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
HIGH PRESSURE OVER THE REGION THIS AFTERNOON WILL DRIFT OFF THE
EASTERN SEABOARD TONIGHT AND CONTINUE TO PROVIDE VFR FOR MOST OF THE
REGION THROUGH THIS EVENING. THE ONE EXCEPTION WILL BE EAST OF LAKE
ONTARIO WHERE A PLUME OF LAKE EFFECT CLOUDS WILL CONTINUE TO PRODUCE
AREAS OF MVFR CIGS THROUGH THIS EVENING. THERE WILL ALSO BE A FEW
FLURRIES...BUT THEY SHOULD REMAIN LIGHT ENOUGH TO KEEP VSBY MAINLY
VFR. OVERNIGHT BOUNDARY LAYER FLOW BECOMES SSW...SO ANY REMAINING
LAKE EFFECT CLOUDS WILL BE CARRIED NORTH INTO CANADA.

OVERNIGHT MID LEVEL CLOUDS WILL INCREASE AND LOWER FROM SOUTHWEST TO
NORTHEAST IN ADVANCE OF THE NEXT SYSTEM. LIGHT SNOW WILL BEGIN TO
OVERSPREAD THE WESTERN SOUTHERN TIER BY AROUND 09Z OR SO WITH VSBY
DETERIORATING TO IFR AS THE SNOW DEVELOPS. THE LIGHT SNOW WILL
SLOWLY OVERSPREAD THE REST OF THE AREA ON SUNDAY WITH VSBY COMING
DOWN TO IFR AS IT DOES SO. THE SNOW WILL SLOWLY SATURATE THE LOW
LEVELS WITH CIGS DROPPING TO MVFR FROM SOUTHWEST TO NORTHEAST ON
SUNDAY...WITH SOME IFR DEVELOPING ACROSS HIGHER TERRAIN.

OUTLOOK...
SUNDAY NIGHT...IFR IN WIDESPREAD SNOW.
MONDAY...AREAS OF MVFR/IFR WITH SNOW SHOWERS...THEN IMPROVING TO
VFR.
TUESDAY...VFR DETERIORATING TO MVFR/IFR LATE WITH A WINTRY MIX
DEVELOPING.
TUESDAY NIGHT...MVFR/IFR WITH A WINTRY MIX CHANGING TO RAIN.
BECOMING WINDY.
WEDNESDAY...WINDY. MVFR WITH A CHANCE OF SNOW SHOWERS.
THURSDAY...MVFR WITH A CHANCE OF SNOW SHOWERS.

&&

.MARINE...
HIGH PRESSURE CENTERED OVER PENNSYLVANIA TODAY WILL PUSH EAST TO THE
COAST TONIGHT. THE RELATIVELY WEAK SFC PRESSURE GRADIENT WILL THUS
KEEP WINDS AND WAVES (IN ICE FREE AREAS) BELOW SMALL CRAFT ADVISORY
CRITERIA.

SUNDAY AND SUNDAY NIGHT...A WAVY FRONTAL BOUNDARY WILL GRADUALLY
PUSH ACROSS THE LOWER GREAT LAKES. WHILE GENERATING WIDESPREAD LIGHT
TO MODERATE SNOW...THIS SCENARIO WILL CONTINUE TO PROMOTE LIGHT
WINDS THROUGH AT LEAST THE FIRST HALF OF SUNDAY NIGHT. WINDS WILL
THEN FRESHEN AHEAD OF A STRONG AREA OF HIGH PRESSURE THAT WILL PUSH
SOUTHEAST FROM THE NORTHERN PLAINS. SMALL CRAFT ADVISORY CONDITIONS
WILL BE LIKELY ON LAKE ONTARIO BY MIDDAY MONDAY.

&&

.HYDROLOGY...
OUR REGION WILL SEE THE FIRST ABOVE FREEZING TEMPERATURES IN OVER
A MONTH AROUND THE MIDDLE OF THE WEEK AS A MODERATELY STRONG AREA
OF LOW PRESSURE CUTS THROUGH THE CENTRAL GREAT LAKES...ALLOWING A
BRIEF SURGE OF WARM AIR TO ENTER OUR REGION TUESDAY NIGHT. EXPECT
A WINTRY MIX INITIALLY LATE TUESDAY AFTERNOON AND EVENING AS WARM
AIR ALOFT MOVES IN OVER STUBBORN COLD AIR AT THE SURFACE. A BRIEF
SURGE OF NEAR SURFACE WARMING JUST AHEAD OF THE COLD FRONT WILL
CHANGE ALL THE PRECIP OVER TO RAIN FOR A BRIEF TIME TUESDAY NIGHT
BEFORE COLD AIR COMES RUSHING BACK INTO THE AREA WEDNESDAY
MORNING.

QPF POTENTIAL WITH THIS SYSTEM APPEARS TO BE IN THE HALF TO THREE
QUARTER OF AN INCH RANGE...BUT AT LEAST A PORTION OF THAT WILL
FALL IN SOME SORT OF FROZEN WINTRY PRECIP. THE DEEP SNOWPACK WILL
LIKELY ABSORB A GOOD PORTION OF THE PRECIPITATION...AND HELP TO
REDUCE RUNOFF. ALL OF THE AREA CREEKS AND RIVERS HAVE VERY
EXTENSIVE ICE PACK...HOWEVER IT DOES NOT APPEAR IT WILL BE WARM
ENOUGH FOR A LONG ENOUGH PERIOD OF TIME TO ALLOW THE ICE TO BREAK
UP AND BEGIN TO MOVE.

GIVEN THE ABOVE EXPECTATIONS...FLOODING POTENTIAL APPEARS LOW FOR
THE MIDWEEK PERIOD. THE ONLY POTENTIAL ISSUE MAY BE MINOR FLOODING
IN POOR DRAINAGE AREAS...ESPECIALLY WHERE SNOW IS BLOCKING STORM
DRAINS.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...WINTER WEATHER ADVISORY FROM 4 AM SUNDAY TO 7 AM EST MONDAY
     FOR NYZ019>021.
MARINE...NONE.

&&

$$

SYNOPSIS...HITCHCOCK/RSH
NEAR TERM...HITCHCOCK/RSH
SHORT TERM...SMITH/WCH
LONG TERM...SMITH
AVIATION...HITCHCOCK
MARINE...RSH
HYDROLOGY...HITCHCOCK




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