Area Forecast Discussion
Issued by NWS Buffalo, NY

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000
FXUS61 KBUF 291421
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1021 AM EDT SUN MAR 29 2015

.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY DRIFT AWAY FROM THE AREA TODAY AND STILL
SUPPORT PLENTY OF SUNSHINE. LOW PRESSURE WILL PASS JUST NORTH OF THE
GREAT LAKES TONIGHT AND MONDAY BRINGING GUSTY WINDS AND A LIGHT MIX
OF WET SNOW AND RAIN WITH SOME MINOR SLUSHY ACCUMULATIONS ACROSS
HIGHER TERRAIN. ANOTHER SYSTEM MAY BRING WET SNOW AND RAIN TO
WESTERN NY TUESDAY BEFORE HIGH PRESSURE BRINGS A RETURN TO DRY
WEATHER FOR WEDNESDAY. TEMPERATURES WILL REMAIN BELOW NORMAL EARLY
IN THE WEEK BEFORE A STRONG PUSH OF WARMING ARRIVES ON THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AT 1000 AM...BRIGHT SUNNY SKIES WERE IN PLACE ACROSS THE REGION
WITH CLOUDS ASSOCIATED WITH AN APPROACHING FRONT STILL BACK ACROSS
MICHIGAN. THESE WILL MOVE IN FROM WEST TO EAST THIS
AFTERNOON...BUT AHEAD OF THIS SUNSHINE WILL HELP WARM THINGS UP A
BIT. SOME OF THE TYPICALLY WARMER LOCATIONS IN THE GENESEE VALLEY
MAY JUST ECLIPSE THE 40F MARK...WITH MOST OTHER LOCATIONS TOPPING
OUT IN THE MID TO UPPER 30S.

THE WEATHER BECOMES MORE ACTIVE TONIGHT AS A POTENT MID LEVEL TROUGH
DIGS FROM NORTHWEST ONTARIO PROVINCE INTO WESTERN QUEBEC BY MONDAY
MORNING WITH AN ASSOCIATED MODERATELY STRONG SURFACE LOW TAKING A
SIMILAR TRACK. A TRAILING OCCLUDED FRONT WILL CROSS OUR REGION
OVERNIGHT AND FOCUS A PERIOD OF DEEPER MOISTURE AND STRONG LOW LEVEL
CONVERGENCE SUPPORTED BY A 50-60 KNOT LOW LEVEL JET. AN INITIAL LEAD
MID LEVEL SHORTWAVE WILL COMBINE WITH THE LOW LEVEL JET SUPPORTED
LOW LEVEL CONVERGENCE FIELD TO BRING A BAND OF PRECIP FROM WEST TO
EAST ACROSS THE AREA TONIGHT...MOVING INTO WESTERN NY AROUND MID
EVENING THEN REACHING THE EASTERN LAKE ONTARIO REGION SHORTLY AFTER
MIDNIGHT. BEHIND THE INITIAL AREA OF PRECIP THERE MAY BE A BRIEF
LULL...BUT ADDITIONAL STRONG DPVA AHEAD OF THE MAIN MID LEVEL TROUGH
AND TERRAIN INDUCED CONVERGENCE AND UPSLOPE EAST OF BOTH LAKES ERIE
AND ONTARIO WILL CONTINUE TO SUPPORT SOME LIGHT PRECIP IN MOST AREAS
OVERNIGHT.

PTYPE WILL BE SOMEWHAT COMPLEX AS THE BOUNDARY LAYER BECOMES FAIRLY
MILD OVERNIGHT. THE FIRST BAND OF PRECIP SHOULD BE MAINLY SNOW...
ALTHOUGH A FEW RAINDROPS MAY MIX IN ON THE LEADING EDGE. EVAPORATIVE
COOLING SHOULD COOL THE COLUMN ENOUGH TO FORCE ANY INITIAL RAIN/SNOW
TO CHANGE TO ALL SNOW IN MOST AREAS. BEHIND THE INITIAL BATCH OF
PRECIP LOW LEVEL WARM ADVECTION WILL ALLOW RAIN TO MIX IN AGAIN LATE
ACROSS LOWER ELEVATIONS AS SURFACE TEMPERATURES CREEP UPWARD THROUGH
THE 30S LATE TONIGHT.

AS FAR AS ACCUMULATIONS GO...LIMITED QPF AND MARGINAL TEMPERATURES
WILL ONLY SUPPORT A SLUSHY COATING IN MOST AREAS. HIGHER TERRAIN MAY
SEE AN INCH OR SO OF ACCUMULATION.

IT WILL BECOME WINDY OVERNIGHT AS THE PRESSURE GRADIENT RAPIDLY
TIGHTENS AND THE LOW LEVEL JET PASSES OVERHEAD. EVAPORATE COOLING
FROM THE FIRST WAVE OF PRECIP MAY HELP TO BRING SOME STRONGER
MOMENTUM DOWN TO THE SURFACE. EXPECT GUSTS OF 25-35 MPH TO BE COMMON
LATER TONIGHT...WITH GUSTS OF 40-45 MPH NORTHEAST OF LAKES ERIE AND
ONTARIO WITH TYPICAL FUNNELING DOWN THE LAKES. A FEW GUSTS TO NEAR
ADVISORY LEVELS CANNOT BE RULED OUT...BUT GIVEN THE LACK OF COLD
ADVECTION AND RELATIVELY POOR LOW LEVEL LAPSE RATES EXPECT MOST OF
THE STRONGER MOMENTUM TO REMAIN ALOFT.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
TROUGHING OVERHEAD ON MONDAY WILL MAKE FOR A SHOWERY AND COOLER DAY.
STEEP LAPSE RATES UNDER THE UPPER-LEVEL TROUGH WILL SUPPORT SOME
SCATTERED...LOW-TOPPED CONVECTIVE RAIN AND SNOW SHOWERS THROUGH THE
DAY MONDAY. AN EMBEDDED VORTICITY MAX IS PROGGED TO SWING THROUGH
THE BASE OF THE TROUGH / AND ACROSS WESTERN NY / BY MID-DAY MONDAY.
THIS SHOULD HELP TO REINVIGORATE SHOWER ACTIVITY AND MAKE IT BRIEFLY
MORE WIDESPREAD. PRECIPITATION TYPE REMAINS SOMEWHAT OF A QUESTION
GIVEN THE RELATIVELY WARM SURFACE TEMPERATURES. HOWEVER WITH STEEP
LAPSE RATES ABOVE THE SURFACE...THE MAJORITY OF THE COLUMN WILL BE
BELOW FREEZING. GIVEN ANY ENHANCED PRECIPITATION RATES IN THE
CONVECTIVE SHOWERS /AND DYNAMICAL COOLING/ EXPECT SNOW WILL LIKELY
BE THE DOMINATE P-TYPE...BUT WILL NOT RULE A LITTLE RAIN MIX AT
TIMES. NEVERTHELESS...SNOW ACCUMULATIONS ARE MAINLY OUT OF THE
QUESTION THROUGH THE DAY MONDAY...EXCEPT FOR A BRIEF LIGHT DUSTING
UNDER A HEAVIER SNOW SHOWER.

WINDS WILL BE NOTICEABLY STRONGER ON MONDAY...AS THE SURFACE LOW
TRACKS JUST NORTH OF THE FORECAST AREA TIGHTENING THE PRESSURE
GRADIENT ACROSS THE AREA. A CORE OF 40 KT WINDS AT 925 - 850 MB WILL
TRACK ACROSS THE FORECAST AREA...HOWEVER WITH ASCENT ASSOCIATED WITH
THE UPPER-LEVEL LOW AND WEAK CAA...IT WILL BE DIFFICULT TO MIX THESE
STRONGER WINDS TO THE SURFACE FOR MUCH OF THE DAY. SOME WIND GUSTS
UP TO 40 MPH COULD BE MIXED DOWN THROUGH THE CONVECTIVE
SHOWERS...AND POTENTIALLY LATER IN THE DAY BEHIND THE VORT MAX
ROTATING ACROSS THE AREA. OTHERWISE WINDS OF 20 TO 30 MPH WILL BE
COMMON ON MONDAY.

BY MONDAY NIGHT...THE TROUGH AXIS PIVOTS OFF THE NEW ENGLAND COAST
AND DRIER AIR WILL FILTER IN FROM THE WEST. GIVEN THE LACK OF
SIGNIFICANT COLD AIR CONNECTION BEHIND THE SURFACE LOW...LOW
TEMPERATURES MONDAY NIGHT INTO TUESDAY MORNING WILL MAINLY BE IN THE
UPPER 20S.

BY TUESDAY...MODELS ARE IN GOOD AGREEMENT ABOUT A CLIPPER SHORTWAVE
DIVING FROM THE UPPER GREAT LAKES INTO PENNSYLVANIA. DISCREPANCIES
BETWEEN THE MODELS ARISE IN THE NORTH-SOUTH POSITION OF THE WAVE AS
IT PASSES BY THE FORECAST AREA. THE NAM REMAINS ON THE MORE
NORTHERLY EDGE OF THE MODEL SPREAD...WHILE THE ECMWF REMAINS ON THE
MORE SOUTHERLY EDGE OF THAT SPREAD. A MORE SOUTHERLY TRACK MEANS
LESS IMPACT TO THE FORECAST AREA...SUPPRESSING THE BULK OF THE
PRECIP INTO PA...AND ALSO COOLER TEMPERATURES ON TUESDAY AS THE
BAROCLINIC ZONE IS SET UP FARTHER SOUTH. HAVE TAKEN A CONSENSUS
APPROACH TO THIS PORTION OF THE FORECAST...WITH THE OFFICIAL FORECAST
USING A BLEND OF THE GFS/NAM/EC/GEM/SREF SOLUTIONS. KEPT LOW END
LIKELY POPS LIMITED TO THE SOUTHERN TIER...WHICH IS THE ONLY PORTION
OF THE FORECAST AREA THAT IS IMPACTED BY BOTH ENDS OF THE MODEL
SPECTRUM. OTHERWISE...POPS TAPER OFF TO CHANCE TOWARD LAKE
ONTARIO...AND NEAR ZERO IN THE NORTH COUNTRY WHICH SHOULD REMAIN OUT
OF THE IMPACT OF THIS SYSTEM. PRECIPITATION TYPE IS AGAIN TRICKY
WITH THIS SYSTEM...AS THE COLD AIR TAP IS LIMITED. FORECAST
SOUNDINGS AGAIN INDICATE A SHALLOW LAYER OF ABOVE FREEZING
TEMPERATURES AT THE SURFACE...AND THUS P-TYPE MAY BECOME DEPENDED ON
RATE / DYNAMICAL COOLING PROCESSES. THUS HAVE CONTINUED TO MAINTAIN
A RAIN / SNOW MIX IN THE FORECAST.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
WEDNESDAY INTO THURSDAY...MODELS ARE IN GOOD AGREEMENT FOR SOME
LOW-AMPLITUDE RIDGING WORKING ACROSS THE AREA. THIS WILL BRING
TEMPERATURES WARMING INTO MID 40S ON WEDNESDAY / WHICH LOOKS LIKE
THE ONLY CERTAIN DRY DAY IN THE EXTENDED FORECAST. AS THE RIDGE AXIS
WORK ACROSS THE AREA ON THURSDAY AND SOUTHWESTERLY FLOW BECOMES
ESTABLISHED ALOFT...TEMPERATURES COULD PUSH WELL INTO 50S / IF NOT
THE LOW 60S IN PORTIONS OF THE AREA. THE TRADE OFF FOR THESE WARMER
TEMPERATURES WILL BE INCREASING CLOUD COVER AND CHANCES FOR
PRECIPITATION TO CLOSE OUT THE WEEK.

MODELS ARE IN GOOD AGREEMENT ABOUT THE WEATHER PATTERN BECOMING MORE
UNSETTLED BY LATE THURSDAY THROUGH SATURDAY AS OVERALL TROUGHING
LOOKS LOOKS TO BE A SURE BET. HOWEVER MODELS CONTINUE TO STRUGGLE
WITH THE EXACT DETAILS AND TIMING OF ANY WEATHER SYSTEMS THAT
DEVELOP OUT OF THIS PATTERN.

&&

.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
VFR WILL PREVAIL THROUGH EARLY THIS EVENING ACROSS THE ENTIRE
REGION. HIGH PRESSURE OVER THE OHIO VALLEY AND LOWER LAKES WILL
SLOWLY DRIFT TO THE EAST COAST TODAY...AND CONTINUE TO PROVIDE CLEAR
SKIES. THIN HIGH CIRRUS LEVEL CLOUDINESS WILL BEGIN TO INCREASE
LATER TODAY AHEAD OF THE NEXT SYSTEM.

THIS EVENING A SHARP MID LEVEL TROUGH AND OCCLUDED FRONT AT THE
SURFACE WILL APPROACH THE AREA. A NARROW ZONE OF FOCUSED ASCENT
ALONG THIS FEATURE WILL PRODUCE A PERIOD OF LIGHT SNOW...ENTERING
WESTERN NY AROUND 02Z THEN OVERSPREADING THE REST OF THE AREA
OVERNIGHT. THE SNOW MAY BRIEFLY MIX WITH RAIN AT THE ONSET...BUT
EVAPORATIVE COOLING SHOULD QUICKLY CHANGE ANY MIX BACK TO ALL SNOW.
THIS WILL PRODUCE AREAS OF IFR VSBY...WITH CIGS INITIALLY STAYING
MAINLY VFR. LATE TONIGHT THE BOUNDARY LAYER MAY AGAIN BECOME MILD
ENOUGH TO ALLOW SOME RAIN TO MIX IN ACROSS THE LAKE PLAINS. BY THIS
TIME THE STEADIER PRECIP WILL HAVE MOVED EAST AND WEAKENED...LEAVING
MORE INTERMITTENT RAIN AND WET SNOW SHOWERS WITH MAINLY MVFR VSBY
EAST OF THE LAKES. WINDS WILL INCREASE THIS EVENING AS THE PRESSURE
GRADIENT TIGHTENS...WITH GUSTS OF OVER 20 KNOTS IN MOST AREAS AND
OVER 30 KNOTS NORTHEAST OF LAKE ERIE DUE TO FUNNELING DOWN THE LAKE.

OUTLOOK...
MONDAY THROUGH TUESDAY...AREAS OF MVFR AND SPOTTY IFR IN RAIN/SNOW
SHOWERS.
WEDNESDAY...VFR.
THURSDAY...VFR/MVFR. A CHANCE OF RAIN SHOWERS.

&&

.MARINE...
HIGH PRESSURE WILL DRIFT AWAY FROM THE REGION AND TOWARDS THE
EASTERN SEABOARD TODAY. SSW WINDS WILL INCREASE TO 15-20 KNOTS IN
THE WAKE OF THE DEPARTING HIGH...BUT THAT WIND DIRECTION WILL KEEP
THE GREATER WAVE ACTION IN THE CANADIAN WATERS OF LAKE ONTARIO.

A MODERATELY STRONG AREA OF LOW PRESSURE WILL PASS BY JUST NORTH OF
THE GREAT LAKES TONIGHT AND MONDAY. THIS WILL BRING A RAPID INCREASE
IN SOUTHWEST WINDS TONIGHT...BECOMING WEST ON MONDAY. THE STRONGER
WINDS WILL BRING AT LEAST HIGH END SMALL CRAFT ADVISORY CONDITIONS
TO THE OPEN PORTIONS OF LAKE ONTARIO...WITH SUSTAINED WINDS REACHING
AROUND 30 KNOTS ON BOTH LAKES. THE GFS REMAINS STRONGER THAN THE NAM
OR CANADIAN GEM GUIDANCE...AND IF IT WERE TO VERIFY LOW END GALES
MAY BE POSSIBLE ON LAKE ONTARIO FOR A FEW HOURS ON MONDAY. FOR NOW
WE HAVE PEAKED THE WINDS AT 30 KNOTS WITH A HIGH END SMALL CRAFT.
WINDS WILL QUICKLY DIMINISH MONDAY NIGHT AS THE SYSTEM MOVES INTO
THE CANADIAN MARITIMES.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 5 AM EDT
         TUESDAY FOR LOZ042-043.

&&

$$

SYNOPSIS...HITCHCOCK
NEAR TERM...APFFEL/HITCHCOCK
SHORT TERM...CHURCH
LONG TERM...CHURCH
AVIATION...HITCHCOCK
MARINE...HITCHCOCK






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