Area Forecast Discussion
Issued by NWS Buffalo, NY

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FXUS61 KBUF 231658
AFDBUF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BUFFALO NY
1258 PM EDT WED APR 23 2014

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL EXIT INTO NEW ENGLAND THIS
AFTERNOON. HIGH PRESSURE WILL DRIFT ACROSS THE LOWER LAKES
TONIGHT WHICH WILL BRING CLEAR SKIES BUT CHILLY OVERNIGHT
TEMPERATURES. TEMPERATURES WILL WARM OVER THE COURSE OF THE
WEEK...WITH THE NEXT CHANCE FOR RAIN ON FRIDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AN UPPER LEVEL DISTURBANCE WILL MOVE OFF THE EAST COAST TONIGHT WITH
PROGRESSIVELY DRIER AIR MOVING IN TO THE LOWER GREAT LAKES REGION.
PRECIPITATION IS DRYING UP AND CLEAR SKIES HAVE MOVED INTO LAKE
ERIE...THE NIAGARA PENINSULA AND FAR WESTERN LAKE ONTARIO.  RESIDUAL
LOW CLOUDS MAY INITIALLY HAVE A TOUGH TIME MIXING OUT EARLY THIS
AFTERNOON IN THE UPSLOPE NW FLOW...BUT EXPECT WIDESPREAD SUBSIDENCE
TO WIN OUT WITH RAPIDLY CLEARING SKIES INLAND LATER THIS AFTERNOON.
THIS SHOULD RESULT IN A CLEAR OR CLEARING PERIOD AROUND SUNSET WITH
PLENTY OF CLEAR SKIES OVERNIGHT.  EXPECT GOOD RADIATIONAL COOLING
WITH FALLING DEWPOINTS HELPING TEMPERATURES TO DIP INTO THE MID 20S
INLAND TO LOW 30S TOWARD THE LAKE SHORES OVERNIGHT.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
LOW AMPLITUDE RIDGING WILL SLIDE ACROSS THE GREAT LAKES THURSDAY.
UPPER LEVEL NORTHWEST CONFLUENT FLOW...WITH GOOD SUBSIDENCE/DRYING AS
PRECIPITABLE WATER VALUES LESS THAN QUARTER OF AN INCH...WILL
SUPPORT A DAY OF ABUNDANT SUNSHINE. THE AIRMASS WILL MODERATE A
BIT...BUT WITH THE SLOWLY DEPARTING 850 MB THERMAL TROUGH...850 MB
TEMPERATURES WILL STILL REMAIN IN THE NEGATIVE SINGLE DIGITS.
THEREFORE...DESPITE THE SUNSHINE HIGHS WILL LIKELY ONLY REACH THE
MID 50S IN MOST AREAS BY MID TO LATE AFTERNOON. A NORTHWEST
GRADIENT ONSHORE FLOW WILL KEEP AREAS ALONG BOTH THE LAKE ONTARIO
AND LAKE ERIE SHORELINE COOLER.

INCREASING MID/HIGH CLOUDINESS EXPECTED THURSDAY NIGHT WITH
DEVELOPING WARM AIR ADVECTION PATTERN AHEAD OF APPROACHING SURFACE
LOW AND MID LEVEL TROUGH. STILL SOME MODEL DIFFERENCES ON HOW MUCH
PRECIPITATION WILL BE REALIZED WITH THIS FIRST PUSH OF WARM AIR
ADVECTION LATE THURSDAY NIGHT. INITIALLY DRY AMBIENT AIRMASS...BUT
TOP DOWN MOISTENING DURING THE OVERNIGHT HOURS SHOULD RESULT IN
SHOWERS DEVELOPING INTO THE WEST BY FRIDAY MORNING.

AN AREA OF SHOWERS IS EXPECTED TO GROW IN COVERAGE DURING THE FIRST
HALF OF FRIDAY AS THE MID LEVEL TROUGH AND ASSOCIATED MOISTURE
PLUME/850-700 MB THETA-E RIDGE AXIS MOVES THROUGH. MEAGER MID LEVEL
LAPSE RATES/SLIGHTLY POSITIVE SHOWALTER INDEX SUPPORTS LEAVING OUT
THE MENTION OF THUNDER.

PRONOUNCED MID LEVEL DRY SLOT WITHIN WESTERLY FLOW DEVELOPS BY
FRIDAY AFTERNOON...SETTING US UP FOR SNEAKY MILDER DAY WITH GOOD
MIXING. HIGH TEMPERATURES COULD GET WELL INTO THE 60S...A FEW  70
PLUS READINGS ARE CERTAINLY IN PLAY IF SKIES CAN OPEN UP QUICKLY
ENOUGH...BUT THERE ARE SOME TIMING CONCERNS WITH THE APPROACH OF A
SECONDARY COLD FRONT.

AN UPPER LEVEL TROUGH AND SECONDARY FRONT PUSH ACROSS THE EASTERN
GREAT LAKES ON FRIDAY NIGHT. THIS WILL HELP TO ENHANCE RAIN SHOWER
ACTIVITY ACROSS WESTERN AND CENTRAL NEW YORK...ESPECIALLY IN FAVORED
UPSLOPE AREAS DOWNWIND OF THE LAKES.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
MEDIUM RANGE MODEL GUIDANCE CONTINUES TO STRUGGLE WITH THE SYNOPTIC
SCALE DETAILS FOR NEXT WEEKEND...WITH BOTH THE GFS AND ECMWF SHOWING
FAIRLY WIDE SWINGS FROM RUN TO RUN. GIVEN THE MODEL DISAGREEMENT...
THE BEST COURSE OF ACTION IS TO STAY FAIRLY CLOSE TO THE PREVIOUS
FORECAST UNTIL BETTER MODEL CONSISTENCY IS SEEN.

LOOKING IN MORE DETAIL...THE GFS REMAINS MUCH FARTHER SOUTH WITH A
STRONG MID LEVEL TROUGH FRIDAY NIGHT AND SATURDAY AS IT SWINGS
THROUGH THE GREAT LAKES AND NEW ENGLAND. THE GFS IS ALSO MUCH
STRONGER WITH A SURFACE REFLECTION. THE ECWMF IS FARTHER NORTH WITH
THE MID LEVEL TROUGH AND MUCH WEAKER WITH THE SURFACE SYSTEM...
ALTHOUGH IT WOULD STILL PRODUCE A FEW SHOWERS SATURDAY. THE GEFS
ENSEMBLE MEMBERS SHOW A VARIETY OF SOLUTIONS RANGING FROM THE
OPERATIONAL GFS AND OPERATIONAL ECMWF TO EVERYTHING IN BETWEEN. IN
SHORT...CONFIDENCE IS FAIRLY HIGH ON SOME SORT OF SYSTEM FOR
SATURDAY BUT THE TRACK AND INTENSITY IS STILL VERY UNCERTAIN. WITH
THIS IN MIND HAVE JUST KEPT POPS IN THE HIGH CHANCE RANGE.
TEMPERATURES WILL BEGIN TO PULL BACK ON SATURDAY...WITH THE CORE OF
THE COOL DOWN LIKELY TO ARRIVE SATURDAY NIGHT AND SUNDAY. BY THIS
TIME THE NEW 12Z ECMWF HAS MADE A DRAMATIC CHANGE TO PREVIOUS
FORECASTS AND BECOMES OUT OF PHASE WITH THE GFS AND MOST ENSEMBLE
MEMBERS. THE NEW ECMWF BECOMES MUCH LESS AMPLIFIED WITH ITS
NORTHEAST CONUS TROUGH...WHICH ALLOWS THE CENTRAL CONUS CUTOFF TO
GET CLOSE ENOUGH TO PRODUCE SHOWERS SUNDAY AND MONDAY. GIVEN THE
MAJOR CHANGE FROM PREVIOUS RUNS...WE WILL DISCARD THE 12Z ECMWF
SOLUTION AND KEEP SUNDAY AND MONDAY MAINLY DRY. SUNDAY WILL LIKELY
BE THE COOLEST DAY BEFORE SOME MODERATION EARLY NEXT WEEK ALTHOUGH
TEMPERATURES WILL STILL REMAIN BELOW AVERAGE.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
RESIDUAL LOW LEVEL MOISTURE WILL BE REPLACED BY DRY AIR AT ALL
LEVELS LATE THIS AFTERNOON/EVENING WITH MVFR CONDITIONS BECOMING VFR
ACROSS ALL OF WESTERN AND CENTRAL NY THROUGH THURSDAY.

OUTLOOK...
FRIDAY THROUGH SUNDAY...VFR/MVFR. A CHANCE OF SHOWERS.
MONDAY...VFR.

&&

.MARINE...
LOW PRESSURE WILL DRIFT ACROSS MAINE THIS MORNING BEFORE MAKING ITS
WAY ACROSS NOVA SCOTIA LATER TODAY WHILE HIGH PRESSURE OVER THE
MISSISSIPPI VALLEY WILL SLOWLY MOVE EAST. THE RELATIVELY TIGHT SFC
PRESSURE GRADIENT BETWEEN THE TWO SYSTEMS WILL PROMOTE MODERATE TO
FRESH NORTHWESTERLIES...RESULTING IN SMALL CRAFT ADVISORIES FOR
LAKE ONTARIO INTO TONIGHT.

AS THE SFC HIGH DRIFTS ACROSS THE LOWER GREAT LAKES TONIGHT...WINDS
WILL WEAKEN WITH ADVISORIES EXPIRING FROM WEST TO EAST. LIGHT WINDS AND
NEGLIGIBLE WAVES WILL BE FOUND ON THE LOWER GREAT LAKES ON THURSDAY.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THURSDAY FOR LOZ043>045.
         SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
         LOZ042.

&&

$$

SYNOPSIS...SMITH/ZAFF
NEAR TERM...APFFEL/SMITH/ZAFF
SHORT TERM...TMA
LONG TERM...HITCHCOCK
AVIATION...APFFEL/ZAFF
MARINE...APFFEL/RSH/SMITH








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